1, 3-butanediol product and method for producing 1, 3-butanediol

Abstract

Provided is a high-purity 1, 3-butanediol product which is colorless and odorless (or almost colorless and odorless), is not susceptible to the occurrence of coloration and odor due to the passage of time, and is not susceptible to the occurrence of an increase in acid concentration due to the passage of time even in a water-containing state. The invention discloses a 1, 3-butanediol product. At least one of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butyraldehyde, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), and the total content of the compound represented by formula (4) and the compound represented by formula (5) is less than 8 ppm.

Description

[0001] This application is a divisional application of an application filed on December 23, 2020, with application number 202080090582.0 and invention name “1,3-Butanediol products and methods for producing 1,3-Butanediol”. Technical Field

[0002] The present disclosure relates to a method for producing 1,3-butanediol and a 1,3-butanediol product. This application claims priority to Japanese Patent Application Nos. 2019-239974, 2019-239975, 2019-239976, 2019-239977, 2019-239978, and 2019-239979, filed in Japan on December 28, 2019; Japanese Patent Application No. 2020-006660, filed in Japan on January 20, 2020; and Japanese Patent Application No. 2020-018910, filed in Japan on February 6, 2020, the contents of which are incorporated herein by reference. Background Art

[0003] 1,3-Butanediol is a colorless, transparent, and odorless liquid with low volatility, low toxicity, high hygroscopicity, and excellent chemical stability. As a result, 1,3-Butanediol's applications range from raw materials for various synthetic resins and surfactants to cosmetics, desiccant, high-boiling-point solvents, and antifreeze. In recent years, 1,3-Butanediol has particularly attracted attention for its excellent properties as a humectant, boosting demand in the cosmetics industry.

[0004] 1,3-Butanediol obtained by existing production methods has the problem of increasing its acid concentration (acidity) when stored for long periods of time while still containing water. The cause of this increase in acid concentration is unclear, but it is believed to be related to byproducts contained in the crude 1,3-butanediol. Cosmetics typically contain water, and a long period of time is required between production and actual use by ordinary consumers. Furthermore, cosmetics require strict control of their liquid properties for reasons such as storage stability. When 1,3-butanediol obtained by existing methods is used in cosmetics, the increased acid concentration can disrupt the cosmetic's liquid balance, potentially losing its intended effects. Furthermore, the increased acid concentration in cosmetics can cause the user's skin to become rough. Furthermore, even cosmetics that do not contain water can sometimes increase their acid concentration due to moisture absorption during use and storage. Therefore, there is a demand to remove byproducts from crude 1,3-butanediol and purify it to a high degree.

[0005] In addition, the 1,3-butanediol obtained by the existing production method sometimes has an odor due to the influence of by-products. In addition, even if the product is transparent immediately after production, it may sometimes be colored due to the passage of time, which becomes a problem during long-term storage. For example, when using cosmetics and storing them after use, the cosmetics are exposed to the air. In addition, when manufacturing cosmetics, the work is usually carried out in an air atmosphere, and heating is sometimes used for the purpose of sterilization. When the 1,3-butanediol obtained by the existing method is used in cosmetics, it may be colored due to the presence of air and the influence of heating. In order to solve such problems, it is required to remove by-products from crude 1,3-butanediol and purify the 1,3-butanediol.

[0006] As a method for obtaining high-purity 1,3-butanediol, a method has been proposed in which crude 1,3-butanediol obtained by hydrogen reduction of aldols is distilled by adding caustic soda. Furthermore, a method has been proposed in which an alkali metal base is added to the crude 1,3-butanediol from which high-boiling-point substances have been removed, followed by heat treatment, the 1,3-butanediol is distilled off, the alkali metal compound and high-boiling-point substances are separated as a residue, and low-boiling-point substances are subsequently removed by distillation from the 1,3-butanediol fraction (Patent Documents 1 to 6). Various methods for purifying 1,3-butanediol have been proposed in this manner to obtain high-purity 1,3-butanediol.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 7-258129

[0010] Patent Document 2: International Publication No. 00 / 07969

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2001-213822

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2001-213824

[0013] Patent Document 5: Japanese Patent Application Laid-Open No. 2001-213825

[0014] Patent Document 6: Japanese Patent Application Laid-Open No. 2001-213828 Summary of the Invention

[0015] Problems to be solved by the invention

[0016] However, 1,3-butanediol products obtained by these purification methods still have the following problems: they contain by-products and have an odor; if they contain water, the acid concentration increases over time; and they are prone to coloration over time.

[0017] 1,3-Butanediol can be produced, for example, by the following methods: (1) reduction (hydrogenation) of butanediol aldehydes; (2) hydrolysis of 1,3-butylene oxide; (3) selective hydrocracking of erythritol; (4) selective water addition of butadiene; (5) hydrogenation of n-butyraldehyde-3-one; (6) hydrogenation of 1-butanol-3-one; (7) hydrogenation of 3-hydroxy-1-butyric acid; (8) hydrogenation of β-butyrolactone; (9) hydrogenation of diketene, etc.

[0018] Among the above-mentioned production methods, the method of obtaining 1,3-butanediol by (1) reduction (hydrogenation) of aldols is preferred. Among them, in terms of yield, the method of reducing aldols in a liquid phase is preferred. The reason is that aldols have a high boiling point; aldols are unstable to heat and easily undergo dehydration reaction at high temperature to produce crotonaldehyde, etc.; and, between the dehydration reaction and the reduction reaction (hydrogenation reaction) at high temperature, the reaction rate of the former is faster. That is, when reducing aldols in a gas phase, it is necessary to set the reaction system to a high temperature, but if a high temperature is applied to the aldols, a dehydration reaction occurs to produce crotonaldehyde, etc., and by-products such as butanol are produced through the subsequent reduction reaction. Therefore, the yield of the target 1,3-butanediol is relatively reduced. Therefore, in order to obtain a high-purity 1,3-butanediol product, liquid phase reduction is more preferable than gas phase reduction.

[0019] When producing 1,3-butanediol, byproducts are often generated during the production process. For example, when producing 1,3-butanediol through hydrogen reduction of aldols, the following byproducts are produced: low-boiling-point substances (low-boiling-point compounds) with unsaturated bonds, such as acetaldehyde, butyraldehyde, crotonaldehyde, acetone, and methyl vinyl ketone; their condensates (e.g., trimers of acetaldehyde); hydrides of these condensates; and condensates of 1,3-butanediol and these low-boiling-point substances (e.g., acetals of 1,3-butanediol and aldols). Furthermore, the following byproducts are produced: acetals of crotonaldehyde and 1,3-butanediol; acetals of acetaldehyde and 1,3-butanediol; and acetals of hydrogenated products of aldols, acetaldehyde, and the trimer of acetaldehyde. In addition, the following by-products are produced: acetic acid, which is contained as an impurity in the aldols used as raw materials, and the condensation product of acetic acid and 1,3-butanediol (ester of acetic acid and 1,3-butanediol) used to neutralize the caustic soda used in the production of aldols. These by-products have the properties of causing coloration, odor, and acidity.

[0020] As for the above-mentioned acetal body, it is not certain whether it is a substance that causes coloration, a substance that causes odor, or a substance that causes acidity. It is also believed that it has all the properties, but it is believed that it strongly has the properties of a substance that causes odor. Specifically, although the possibility of the above-mentioned acetal body itself being a substance that causes odor is low, it may produce a substance that causes odor due to changes over time or heating. In addition, the above-mentioned acetal body sometimes produces butanol due to hydrolysis. This butanol is a substance that causes odor and has an oxidation (coloration) promoting effect. Therefore, this butanol can also be said to be a substance that causes coloration. Here, the substance that causes coloration is defined as: not only a substance that currently has a hue itself, but also a substance that changes over time to a substance that has a hue. The substance that causes odor is defined as: not only a substance that currently emits an odor itself, but also a substance that changes over time to a substance that emits an odor. The substance that causes acidity is defined as: a substance whose acid concentration increases over time when it contains water.

[0021] It is unclear whether the ester is a substance that causes coloration, odor, or acidity, and while it is believed to possess all of these properties, it is believed to possess strong properties of both. This is because when the ester is hydrolyzed by water, acetic acid is produced.

[0022] It should be noted that when producing 1,3-butanediol, byproducts produced during the production process are believed to include, in addition to the aforementioned acetals and esters, various other byproducts corresponding to substances that cause coloration, odor, or acidity. For example, the aforementioned hydrogenated product of the trimer of acetaldehyde is believed to be any of these substances.

[0023] Even using existing purification methods such as distillation, these byproducts are difficult to completely remove. This is believed to be because during the purification steps for crude 1,3-butanediol, the crude 1,3-butanediol is subjected to high temperatures and alkaline treatment, which generates new byproducts. For these reasons, as described above, the 1,3-butanediol products described in Patent Documents 1 to 6 contain large amounts of byproducts, resulting in odor, coloration over time, and, in the presence of water, an increase in acid concentration over time.

[0024] Therefore, an object of the present disclosure is to provide a high-purity 1,3-butanediol product that is colorless and odorless (or almost colorless and odorless), is less likely to discolor or generate odor over time, and is less likely to increase in acid concentration over time even in a water-containing state.

[0025] Furthermore, another object of the present disclosure is to provide a moisturizing agent and a cosmetic material that have excellent moisturizing performance and can maintain high quality for a long period of time.

[0026] Furthermore, another object of the present disclosure is to provide a method for efficiently and industrially producing high-purity 1,3-butanediol having the following characteristics: it is colorless and odorless (or almost colorless and odorless), is less likely to discolor over time, and is less likely to increase in acid concentration over time even in a water-containing state.

[0027] Technical Solution

[0028] The inventors of the present disclosure have conducted in-depth research to achieve the above-mentioned purpose and have found that nine specific compounds, in addition to acetaldehyde and crotonaldehyde, are the causative substances of coloration, odor, coloration increase over time, odor generation over time, and acid concentration increase. In addition, a method for suppressing the mixing of these compounds into 1,3-butanediol products has been found. More specifically, it has been found that by adjusting the content of specific impurities and the 1,3-butanediol concentration in the charge liquid of the product tower and the high-boiling tower so as to be within a specific range, and further adjusting the reaction conditions in the reaction process (for example, the hydrogenation process of butanediol aldehydes, etc.) (especially, increasing the hydrogen partial pressure in the reactor), 1,3-butanediol with the following characteristics can be obtained: colorless, odorless (or, almost colorless, odorless), not prone to coloration and odor generation caused by time, and not prone to acid concentration increase caused by time even in a water-containing state. The present disclosure is based on these insights and has been completed through further research.

[0029] That is, the present disclosure provides a 1,3-butanediol product, wherein at least one of the eight contents including the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanediol, the content of the compound represented by the following formula (1), the content of the compound represented by the following formula (2), the content of the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5) is less than 8 ppm.

[0030]

[0031] For the 1,3-butanediol product, the sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4), and the content of the compound represented by formula (5) may be less than 71 ppm.

[0032] For the 1,3-butanediol product, it is preferred that at least the aldol content is less than 8 ppm.

[0033] In the 1,3-butanediol product, it is preferred that the content of at least the compound represented by formula (3) is less than 8 ppm.

[0034] In the 1,3-butanediol product, it is preferred that the total content of methyl vinyl ketone, acetone, and butyraldehyde is 24 ppm or less.

[0035] In the 1,3-butanediol product, it is preferred that the total content of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (4), and the compound represented by formula (5) is 24 ppm or less.

[0036] Furthermore, for the 1,3-butanediol product, it is preferred that the acetaldehyde content is less than 4 ppm and the crotonaldehyde content is less than 2 ppm.

[0037] Furthermore, the 1,3-butanediol product preferably has an acid concentration (calculated as acetic acid) of less than 11 ppm, and an acid concentration (calculated as acetic acid) of less than 23 ppm after a 90 wt% aqueous solution is maintained at 100° C. for one week.

[0038] Furthermore, the 1,3-butanediol product preferably has an APHA of 6 or less, and an APHA of 78 or less after being kept at 180° C. for 3 hours in an air atmosphere.

[0039] Furthermore, the 1,3-butanediol product preferably has an initial boiling point higher than 203° C. and / or a dry point of 209° C. or lower.

[0040] Furthermore, it is preferred that the 1,3-butanediol product have a potassium permanganate test value of 30 minutes or more.

[0041] The present disclosure also provides a moisturizer comprising the 1,3-butanediol preparation.

[0042] The present disclosure also provides a cosmetic comprising the moisturizing agent.

[0043] Furthermore, the present disclosure provides a method for producing 1,3-butanediol (hereinafter sometimes referred to as "production method 1 of the present disclosure"), which obtains purified 1,3-butanediol from a crude reaction liquid containing 1,3-butanediol. The method for producing 1,3-butanediol comprises: a dehydration step for removing water by distillation; a high-boiling point removal step for removing high-boiling point components by distillation; and a product distillation step for obtaining purified 1,3-butanediol, wherein in the product distillation step, a 1,3-butanediol charge liquid is distilled in a product column at a reflux ratio of 0.3 or higher, the 1,3-butanediol charge liquid having an acetaldehyde content of 500 ppm or less, a crotonaldehyde content of 200 ppm or less, and a water content of 0.7 wt% or less, and a 1,3-butanediol concentration of 97.6 area % or higher as determined by gas chromatography analysis under the following conditions.

[0044] (Gas chromatography analysis conditions)

[0045] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0046] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0047] Sample introduction temperature: 250°C.

[0048] Carrier gas: Helium.

[0049] Column gas flow rate: 1 mL / min.

[0050] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0051] In the above production method, at least a portion of the distillate from the product column may be reused in a dehydration step, a dealcoholization step / low boiling point removal step, or a step before these steps, which are steps before the product distillation step.

[0052] The present disclosure also provides a method for producing 1,3-butanediol (hereinafter sometimes referred to as "production method 2 of the present disclosure"), which obtains purified 1,3-butanediol from a crude reaction liquid containing 1,3-butanediol, the method for producing 1,3-butanediol comprising: a dehydration step of removing water by distillation; and a high-boiling point removal step of removing high-boiling point components by distillation, wherein a charge liquid containing 1,3-butanediol is distilled in a high-boiling point removal column used in the high-boiling point removal step under conditions of a reflux ratio of 0.03 or higher, the charge liquid containing 1,3-butanediol has an acetaldehyde content of 500 ppm or less, a crotonaldehyde content of 200 ppm or less, and a water content of 3 weight % or less, and a 1,3-butanediol concentration obtained by gas chromatography analysis under the following conditions is 96.7 area % or higher.

[0053] (Gas chromatography analysis conditions)

[0054] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0055] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0056] Sample introduction temperature: 250°C.

[0057] Carrier gas: Helium.

[0058] Column gas flow rate: 1 mL / min.

[0059] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0060] In each of the above-mentioned production methods, the crude reaction liquid containing 1,3-butanediol may be a crude reaction liquid obtained by hydrogen reduction of aldols.

[0061] In each of the above-mentioned production methods, the production method of 1,3-butanediol may also include at least one step selected from the following steps: an alkali treatment step of treating a process stream containing 1,3-butanediol with an alkali; a desalting step of removing salt from the process stream containing 1,3-butanediol; and a dealcoholization step of removing low-boiling substances including alcohol from the process stream containing 1,3-butanediol.

[0062] In the present disclosure, a "1,3-butanediol product" refers to a composition in which 1,3-butanediol accounts for the majority of the constituent components (for example, a 1,3-butanediol content of 95% by weight or more, preferably 98% by weight or more).

[0063] Effects of the Invention

[0064] The present disclosure provides a high-purity 1,3-butanediol product that is colorless and odorless (or nearly colorless and odorless), is less likely to discolor or odor over time, and is less likely to increase in acid concentration over time even in a water-containing state.

[0065] Furthermore, according to the present disclosure, a moisturizing agent and a cosmetic material are provided that have excellent moisturizing performance and can maintain high quality for a long period of time.

[0066] Furthermore, according to the method for producing 1,3-butanediol disclosed herein, high-purity 1,3-butanediol can be produced industrially and efficiently, having the following characteristics: it is colorless and odorless (or almost colorless and odorless), is less likely to discolor or generate odor over time, and is less likely to increase in acid concentration over time even in a water-containing state. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a flow chart of a method for producing (purifying) a 1,3-butanediol product according to the present disclosure.

[0068] Figure 2 This is a gas chromatography analysis spectrum of the 1,3-butanediol product in Example 1.

[0069] Figure 3 This is a gas chromatography analysis spectrum of the 1,3-butanediol product in Example 12.

[0070] Figure 4 This is a gas chromatography analysis spectrum of the 1,3-butanediol product in Comparative Example 2. DETAILED DESCRIPTION

[0071] [1,3-Butanediol products]

[0072] In the 1,3-butanediol product of the present disclosure, at least one of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanediol, the content of the compound represented by the following formula (1), the content of the compound represented by the following formula (2), the content of the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5) is less than 8 ppm.

[0073]

[0074] The contents of the above-mentioned methyl vinyl ketone, acetone, butyraldehyde, butyral, the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5) can be quantified by GC-MS analysis under the following conditions. In GC-MS analysis, even very small peaks are all subjected to mass analysis to quantify each component. Since a specific mass is analyzed, even if other impurities overlap with the peak, substances with different masses are not sensed, and the sensitivity is higher than that of the GC analysis described later. In this specification, the unit "ppm" of the content of each component obtained by GC-MS analysis means "weight ppm".

[0075] (GC-MS Analysis Conditions)

[0076] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0077] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0078] Sample introduction temperature: 250℃.

[0079] Carrier gas: Helium.

[0080] Column gas flow rate: 1 mL / min.

[0081] Ion source temperature: EI 230°C, CI 250°C.

[0082] Q-pole temperature: 150°C.

[0083] Sample: Provided directly for analysis.

[0084] Under the above analysis conditions, the retention time of the peaks of methyl vinyl ketone, acetone, butyraldehyde, aldol [CH3CH(OH)CH2CH(=O)], and the compound represented by the following formula (1) is generally shorter than the retention time of the peak of 1,3-butanediol. Under the above analysis conditions, the retention time of the peak of 1,3-butanediol is generally 5.5 to 7 minutes. Under the above analysis conditions, when the relative retention time of the peak of 1,3-butanediol is set to 1.0, the relative retention time of the peak of methyl vinyl ketone is 0.3 to 0.5, the relative retention time of the peak of acetone is 0.3 to 0.5, the relative retention time of the peak of butyraldehyde is 0.3 to 0.5, the relative retention time of the peak of aldol is 0.4 to 0.6, and the relative retention time of the peak of the compound represented by the formula (1) is 0.6 to 0.8. It should be noted that the compound represented by the formula (1) is an acetal compound obtained by the reaction of acetaldehyde and 1,3-butanediol.

[0085] Under the above analysis conditions, the peak retention times of the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5) are generally longer than the peak retention time of 1,3-butanediol. Under the above analysis conditions, when the relative retention time of the peak of 1,3-butanediol is set to 1.0, the relative retention time of the peak of the compound represented by formula (2) is 1.3 to 1.7, the relative retention time of the peak of the compound represented by formula (3) is 1.0 to 1.2, the relative retention time of the peak of the compound represented by formula (4) is 1.6 to 2.0, and the relative retention time of the peak of the compound represented by formula (5) is 1.3 to 1.7. It should be noted that the compound represented by formula (2) is an acetal compound obtained by the reaction of crotonaldehyde and 1,3-butanediol. The compound represented by formula (3) is 1,3-butanediol monoacetate obtained by the reaction of acetic acid and 1,3-butanediol. The compound represented by formula (4) and the compound represented by formula (5) are acetals of acetaldehyde polymers [the compound represented by formula (4) has a hydroxyl group, and the compound represented by formula (5) does not have a hydroxyl group].

[0086] In the 1,3-butanediol product of the present disclosure, at least one of the eight contents, namely, the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanediol, the content of the compound represented by the following formula (1), the content of the compound represented by the following formula (2), the content of the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5), is less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, and still more preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less). Therefore, among the eight contents, one content may be less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), two contents may be less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), three contents may be less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), or four contents may be less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less). or less), or five contents are less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), or six contents are less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), or seven contents are less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less), or all eight contents are less than 8 ppm (for example, 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0087] In the 1,3-butanediol product, it is preferred that at least four (four, five, six, seven, or eight) of the eight contents, namely, the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of aldol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), and the total content of the compound represented by formula (4) and the compound represented by formula (5), are less than 8 ppm (e.g., 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less). It is particularly preferred that all of the eight contents are less than 8 ppm (e.g., 7 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, further preferably 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0088] Furthermore, the 1,3-butanediol product may be the sum of two of the eight contents, namely, the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of aldol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), and the total content of the compound represented by formula (4) and the compound represented by formula (5) (for example, the sum of the content of methyl vinyl ketone and the content of acetone; the sum of the content of methyl vinyl ketone and the content of butyraldehyde; the sum of the content of methyl vinyl ketone and the content of aldol; the sum of the content of methyl vinyl ketone and the content of the compound represented by formula (1); the sum of the content of methyl vinyl ketone and the content of the compound represented by formula (2); the sum of the content of methyl vinyl ketone and the content of aldol); At least one (for example, one, two, three, four, ... or all) of the following (for example, the sum of the content of methyl ketone and the content of the compound represented by formula (3); the sum of the content of methyl vinyl ketone and the total content of the compound represented by formula (4) and the compound represented by formula (5); the sum of the content of acetone and the content of butyraldehyde, etc.) is less than 16 ppm (for example, 15 ppm or less, preferably 14 ppm or less, more preferably 13 ppm or less, further preferably 12 ppm or less, particularly preferably 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less or 0.5 ppm or less).

[0089] Furthermore, the 1,3-butanediol product may be the sum of three of the eight contents, namely, the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butyral, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), and the total content of the compound represented by formula (4) and the compound represented by formula (5) (for example, the sum of the content of methyl vinyl ketone, the content of acetone, and the content of butyraldehyde; the sum of the content of methyl vinyl ketone, the content of butyral, and the content of the compound represented by formula (1); the content of acetone At least one (for example, one, two, three, four, ... or all) of the above (for example, the content of butyraldehyde and the sum of the content of butyral) is less than 24 ppm (for example, 20 ppm or less, preferably 18 ppm or less, more preferably 16 ppm or less, further preferably 14 ppm or less, particularly preferably 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less or 0.5 ppm or less).

[0090] In addition, the 1,3-butanediol product may be the sum of four contents among the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of aldol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), and the total content of the compound represented by formula (4) and the compound represented by formula (5) (for example, the sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, and the content of aldol; the content of acetone, the content of butyraldehyde, the content of aldol, and the total content of the compound represented by formula (1)). At least one (for example, one, two, ... or all) of the above (the sum of the contents of the compounds shown, etc.) is less than 32 ppm (for example, 30 ppm or less, preferably 25 ppm or less, more preferably 20 ppm or less, further preferably 18 ppm or less, particularly preferably 16 ppm or less, 14 ppm or less, 12 ppm or less, 10 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less or 0.5 ppm or less).

[0091] Furthermore, for the 1,3-butanediol product, the sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanediol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4), and the content of the compound represented by formula (5) may be less than 71 ppm (for example, 60 ppm or less, preferably 50 ppm or less, more preferably 40 ppm or less, further preferably 30 ppm or less, particularly preferably 20 ppm or less, 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 10 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0092] Furthermore, in the case of the 1,3-butanediol product, it is preferred that the sum of the content of methyl vinyl ketone, acetone, butyraldehyde, aldol, and the content of the compound represented by formula (1), which are impurities generally having a shorter GC retention time than that of 1,3-butanediol, is less than 47 ppm (e.g., 40 ppm or less, preferably 30 ppm or less, more preferably 25 ppm or less, further preferably 20 ppm or less, particularly preferably 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 10 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less). m or less), and the sum of the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4), and the content of the compound represented by formula (5), which are impurities that generally have a longer GC retention time than 1,3-butanediol, is less than 24 ppm (for example, 20 ppm or less, preferably 18 ppm or less, more preferably 16 ppm or less, further preferably 14 ppm or less, particularly preferably 13 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0093] Furthermore, for the 1,3-butanediol product disclosed herein, it is preferred that the aldol content is at least less than 8 ppm. Aldol generates crotonaldehyde upon heating. Crotonaldehyde may be a substance that causes coloration, odor, or acidity. The aldol content is more preferably 7 ppm or less, and further preferably 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less.

[0094] In the 1,3-butanediol product disclosed herein, it is preferred that the content of at least the compound represented by formula (3) be less than 8 ppm. The compound represented by formula (3) produces acetic acid upon hydrolysis, generating an acetic acid odor. Furthermore, the acid concentration (acid content) of the product is increased. The content of the compound represented by formula (3) is more preferably 7 ppm or less, and even more preferably 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less.

[0095] In the 1,3-butanediol product disclosed herein, the combined content of methyl vinyl ketone, acetone, and butyraldehyde is preferably 24 ppm or less. These compounds all have carbonyl groups and may be substances that cause coloration, odor, or acidity. The combined content of methyl vinyl ketone, acetone, and butyraldehyde is more preferably 20 ppm or less, and even more preferably 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less.

[0096] In the 1,3-butanediol product disclosed herein, the total content of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (4), and the compound represented by formula (5) is preferably 24 ppm or less. These compounds are all acetal compounds and produce acetaldehyde upon hydrolysis. Acetaldehyde may be a substance that causes coloration, odor, or acidity.

[0097] In addition, in the 1,3-butanediol product disclosed herein, it is preferred that the acetaldehyde content is less than 4 ppm (in particular, less than 2 ppm). In addition, it is preferred that the crotonaldehyde content is less than 2 ppm (in particular, less than 1.2 ppm). As described above, acetaldehyde and crotonaldehyde may be substances that cause coloration, substances that cause odor, or substances that cause acidity. In addition, the potassium permanganate test value of the product is reduced. The acetaldehyde content and crotonaldehyde content in the 1,3-butanediol product can be quantified by the GC-MS analysis (gas chromatography-mass spectrometry).

[0098] Under the above GC-MS analysis conditions, when the relative retention time of the 1,3-butanediol peak is set to 1.0, the relative retention time of the acetaldehyde peak is 0.3 to 0.5, and the relative retention time of the crotonaldehyde peak is 0.3 to 0.5.

[0099] The acetaldehyde content in the 1,3-butanediol product is more preferably 1.8 ppm or less, further preferably 1.7 ppm or less, 1.5 ppm or less, 1.4 ppm or less, 1.3 ppm or less, 1.2 ppm or less, 1.1 ppm or less, 1.0 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, or 0.5 ppm or less, and particularly preferably 0.3 ppm or less (e.g., 0.2 ppm or less). Furthermore, the crotonaldehyde content in the 1,3-butanediol product is more preferably 1.0 ppm or less, further preferably 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.4 ppm or less, or 0.3 ppm or less, and particularly preferably 0.2 ppm or less (e.g., 0.1 ppm or less).

[0100] Furthermore, the 1,3-butanediol product preferably has an acid concentration (calculated as acetic acid) of less than 11 ppm, and preferably has an acid concentration (calculated as acetic acid) of less than 23 ppm after a 90 wt% aqueous solution is maintained at 100° C. for one week.

[0101] The 1,3-butanediol product of the present disclosure preferably has an acid concentration (calculated as acetic acid) of, for example, 10 ppm or less (preferably 9 ppm or less, more preferably 8 ppm or less, even more preferably 7 ppm or less, particularly preferably 6 ppm or less, and most preferably 5 ppm or less, 4 ppm or less, or 3 ppm or less). Furthermore, after a 90 wt% aqueous solution is maintained at 100°C for one week, the acid concentration (calculated as acetic acid) is, for example, 20 ppm or less (preferably 19 ppm or less, 18 ppm or less, 17 ppm or less, or 16 ppm or less, more preferably 15 ppm or less, even more preferably 14 ppm or less, 13 ppm or less, 12 ppm or less, or 11 ppm or less, and particularly preferably 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, or 2 ppm or less). The 90 wt% aqueous solution refers to an aqueous solution prepared by mixing the 1,3-butanediol product with water (e.g., pure water) to adjust the 1,3-butanediol product to 90 wt%.

[0102] Regarding the acid concentration (in terms of acetic acid) of a 90 wt% aqueous solution of the 1,3-butanediol product of the present disclosure, the ratio of the acid concentration after holding at 100°C for one week to the acid concentration before holding [(acid concentration after holding at 100°C for one week) / (acid concentration before holding) × 100 (%)] is preferably 200% or less, more preferably 150% or less, and even more preferably 120% or less.

[0103] With respect to the 1,3-butanediol product disclosed herein, it is ideal that the APHA (Hasson color) is, for example, 6 or less (preferably 5 or less, more preferably 4 or less, further preferably 3 or less, and particularly preferably 2 or less), and the APHA after being kept at 180° C. for 3 hours in an air atmosphere is, for example, 78 or less (preferably 65 or less, more preferably 60 or less, further preferably 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, and particularly preferably 18 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, or 7 or less). In addition, the APHA after maintaining at 100°C for 75 days in an air atmosphere is, for example, 42 or less (preferably 35 or less, 30 or less, 25 or less, 20 or less, 18 or less, 16 or less, 15 or less, 14 or less, or 13 or less, more preferably 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, or 6 or less, further preferably 5 or less, 4 or less, 3 or less, or 2 or less).

[0104] Regarding the APHA content of the 1,3-butanediol product of the present disclosure, the ratio of APHA after holding at 100°C for 75 days to APHA before holding [(APHA after holding at 100°C for 75 days) / (APHA before holding)] is not particularly limited, but is preferably 10 or less, more preferably 8 or less, even more preferably 7 or less, and particularly preferably 6 or less (e.g., 5 or less, 4 or less, or 3 or less). The above ratio may be 1 or greater and may be 2 or greater.

[0105] Furthermore, the 1,3-butanediol product of the present disclosure preferably has an initial boiling point higher than 203° C. The initial boiling point is preferably 204° C. or higher, more preferably 205° C. or higher, further preferably 206° C. or higher or 207° C., and particularly preferably 208° C. or higher.

[0106] Furthermore, the 1,3-butanediol product of the present disclosure preferably has a dry point of 209° C. or lower.

[0107] Further, in the 1,3-butanediol product of the present disclosure, it is preferable that the potassium permanganate test value (PMT) be 30 minutes or more. The potassium permanganate test value (PMT) is more preferably more than 30 minutes (e.g., 32 minutes or more), further preferably 35 minutes or more (e.g., 40 minutes or more), particularly preferably 50 minutes or more (especially 60 minutes or more).

[0108] Further, in the 1,3-butanediol product of the present disclosure, it is preferable that the peak area ratio (GC area ratio) of 1,3-butanediol be higher than 98.7% in the gas chromatography analysis (GC analysis) under the following conditions. Further, it is preferable that the total peak area ratio of peaks having a shorter retention time than 1,3-butanediol be lower than 0.3%. Further, it is preferable that the total peak area ratio of peaks having a longer retention time than 1,3-butanediol be lower than 1.2%.

[0109] (Conditions of gas chromatography analysis)

[0110] Analysis column: column having a stationary phase of dimethylpolysiloxane (membrane thickness 1.0 μm x length 30 m x inner diameter 0.25 mm).

[0111] Temperature rising conditions: rising from 80°C to 120°C at 5°C / minute, rising to 160°C at 2°C / minute and maintaining for 2 minutes, and further rising to 230°C at 10°C / minute and maintaining for 18 minutes at 230°C.

[0112] Sample introduction temperature: 250°C.

[0113] Carrier gas: helium.

[0114] Column gas flow rate: 1 mL / minute.

[0115] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0116] In the present disclosure, the "peak area ratio" of a peak refers to the proportion of the area of a specific peak appearing in a spectrum to the sum of the areas of all peaks. Further, all peaks refer to, for example, all peaks appearing when analysis is continued until the relative retention time is 7.8 and stopped when the relative retention time of the peak of 1,3-butanediol is set to 1.0. By the peak area ratio being in the above range, there is a tendency that the generation of odor is reduced, the increase in acid concentration over time in a water-containing state is reduced, and discoloration over time is reduced.

[0117] The area ratio of the 1,3-butanediol peak is preferably 98.8% or higher, more preferably 98.9% or higher, further preferably 99% or higher, 99.1% or higher, 99.2% or higher, 99.3% or higher, 99.4% or higher, 99.5% or higher, 99.6% or higher, or 99.7% or higher, and particularly preferably 99.8% or higher.

[0118] The total area ratio of peaks having a shorter retention time than the peak of 1,3-butanediol is preferably 0.28% or less, more preferably 0.25% or less, further preferably 0.23% or less, 0.2% or less, 0.17% or less, 0.15% or less, 0.12% or less, 0.1% or less, 0.07% or less, 0.04% or less, 0.03% or less, 0.02% or less, 0.01% or less, or 0.007% or less, and particularly preferably 0.005% or less (e.g., 0.002% or less).

[0119] The total area ratio of the peaks having a longer retention time than the peak of 1,3-butanediol is preferably 1% or less, more preferably 0.9% or less, further preferably 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less, and particularly preferably 0.1% or less.

[0120] In the 1,3-butanediol product disclosed herein, the water content is preferably less than 0.4% by weight. The water content is preferably 0.3% by weight or less, more preferably 0.2% by weight or less, further preferably 0.1% by weight or less, 0.07% by weight or less, 0.05% by weight or less, 0.03% by weight or less, 0.02% by weight or less, or 0.01% by weight or less, and particularly preferably 0.005% by weight or less. It should be noted that the water content can be quantified using a Karl Fischer moisture analyzer.

[0121] In addition to suppressing the contents of the above-mentioned nine specific compounds, by ensuring that the acetaldehyde content and the crotonaldehyde content are within the above-mentioned ranges, by ensuring that the initial distillation point and the dry point are within the above-mentioned ranges, and by ensuring that the potassium permanganate test value, the area ratio of the 1,3-butanediol peak, the total area ratio of peaks having a shorter retention time than the 1,3-butanediol peak, and the total area ratio of peaks having a longer retention time than the 1,3-butanediol peak are within the above-mentioned ranges, a 1,3-butanediol product with high purity and high quality and little degradation of quality over time can be provided.

[0122] [Moisturizers and cosmetics]

[0123] The moisturizing agent disclosed herein contains the aforementioned 1,3-butanediol product. Therefore, it has excellent moisturizing properties. The moisturizing agent disclosed herein may also contain ingredients other than the aforementioned 1,3-butanediol product, for example, moisturizing agent ingredients other than the aforementioned 1,3-butanediol product. In the moisturizing agent disclosed herein, the content of the aforementioned 1,3-butanediol product is, for example, 10% by weight or greater, preferably 30% by weight or greater, more preferably 50% by weight or greater, further preferably 80% by weight or greater, and particularly preferably 90% by weight or greater. The moisturizing agent may also be composed solely of the aforementioned 1,3-butanediol product.

[0124] The cosmetic disclosed herein includes the aforementioned moisturizing agent. Depending on the type and form of the cosmetic, the amount of the aforementioned 1,3-butanediol product incorporated into the cosmetic disclosed herein may be any amount sufficient to exhibit moisturizing properties. The amount of the aforementioned 1,3-butanediol product incorporated into the cosmetic disclosed herein is, for example, 0.01% to 40% by weight, preferably 0.1% to 30% by weight, more preferably 0.2% to 20% by weight, further preferably 0.5% to 15% by weight, and particularly preferably 1% to 10% by weight.

[0125] In addition to the above-mentioned 1,3-butanediol products, the cosmetics disclosed herein may also contain, for example: other moisturizers; oils such as vegetable oils, hydrocarbon oils, higher fatty acids, higher alcohols, and silicones; surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants; preservatives, metal ion capping agents, thickeners, powders, ultraviolet absorbers, ultraviolet shielding agents, fragrances, and pH adjusters; and medicinal ingredients and physiologically active ingredients such as vitamins, skin activators, blood circulation promoters, whitening agents, antibacterial agents, and anti-inflammatory agents.

[0126] The cosmetics disclosed herein can be formulated into skin cosmetics such as lotions, emulsions, creams, gels, facial masks (packs), and facial masks; and hair cosmetics such as shampoos, conditioners, and hair tonics. Furthermore, they can be formulated into sunscreen cosmetics, makeup cosmetics, and other cosmetics. Furthermore, they can be formulated into pharmaceuticals and quasi-drugs containing medicinal ingredients.

[0127] The cosmetic disclosed herein can be produced by a method known per se.

[0128] [Method for producing 1,3-butanediol]

[0129] The 1,3-butanediol product disclosed herein can be produced using the production method disclosed herein. Production method 1 disclosed herein is a method for producing 1,3-butanediol, which produces purified 1,3-butanediol from a crude reaction solution containing 1,3-butanediol (1,3BG) (hereinafter sometimes referred to as "crude 1,3-butanediol"). The 1,3-butanediol production method comprises: a dehydration step for removing water by distillation; a high-boiling point removal step for removing high-boiling point components by distillation; and a product distillation step for obtaining purified 1,3-butanediol. In the product column used in the product distillation step, a 1,3-butanediol feed liquid is distilled at a reflux ratio of 0.3 or higher, with a liquid concentrated in low-boiling components being distilled from the upper portion of the feed section and 1,3-butanediol being withdrawn from the lower portion of the feed section. The 1,3-butanediol feed liquid has an acetaldehyde content of 500 ppm or less, a crotonaldehyde content of 200 ppm or less, and a water content of 0.7% by weight or less, and a 1,3-butanediol concentration of 97.6 area % or higher as determined by gas chromatography under the following conditions. The 1,3-butanediol thus obtained is colorless and odorless (or nearly colorless and odorless), is less susceptible to coloration over time, and, even in a water-containing state, is less susceptible to an increase in acid concentration over time, thereby enabling the production of a 1,3-butanediol product.

[0130] (Gas chromatography analysis conditions)

[0131] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0132] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0133] Sample introduction temperature: 250℃.

[0134] Carrier gas: Helium.

[0135] Column gas flow rate: 1 mL / min.

[0136] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0137] Production Method 2 of the present disclosure provides a method for producing 1,3-butanediol, comprising obtaining purified 1,3-butanediol from a crude reaction liquid containing 1,3-butanediol. The method comprises: a dehydration step for removing water by distillation; and a high-boiling point removal step for removing high-boiling point components by distillation. In the high-boiling point removal step, a charge liquid containing 1,3-butanediol is distilled in a high-boiling point removal column at a reflux ratio of 0.03 or higher, 1,3-butanediol of further improved purity is distilled from the upper portion of the charge section, and a liquid concentrated in high-boiling point components is withdrawn from the lower portion of the charge section. The charge liquid containing 1,3-butanediol has an acetaldehyde content of 500 ppm or less, a crotonaldehyde content of 200 ppm or less, and a water content of 3% by weight or less, and a 1,3-butanediol concentration of 96.7 area % or higher as determined by gas chromatography analysis under the following conditions. The 1,3-butanediol obtained in this manner is colorless and odorless (or almost colorless and odorless), is less likely to color over time, and is less likely to increase in acid concentration over time even in a water-containing state, thus enabling the production of 1,3-butanediol products.

[0138] The “production method 1 of the present disclosure” and the “production method 2 of the present disclosure” may be collectively referred to as the “production method of the present disclosure”.

[0139] [Crude 1,3-butanediol]

[0140] Examples of crude 1,3-butanediol include: (1) a crude reaction liquid obtained by reduction (hydrogenation) of butanediols; (2) a crude reaction liquid obtained by hydrolysis of 1,3-butylene oxide; (3) a crude reaction liquid obtained by selective hydrocracking of erythritol; (4) a crude reaction liquid obtained by selective water addition of butadiene; (5) a crude reaction liquid obtained by hydrogenation of n-butyraldehyde-3-one; (6) a crude reaction liquid obtained by hydrogenation of 1-butanol-3-one; (7) a crude reaction liquid obtained by hydrogenation of 3-hydroxy-1-butyric acid; (8) a crude reaction liquid obtained by hydrogenation of β-butyrolactone; and (9) a crude reaction liquid obtained by hydrogenation of diketene, etc. In the present disclosure, the crude 1,3-butanediol may be one or a mixture of two or more of the above (1) to (9). As the crude 1,3-butanediol, a crude reaction liquid obtained by the reduction (particularly, liquid-phase reduction) of aldols (1) is preferred.

[0141] Hereinafter, the case where the crude reaction liquid obtained by reducing (hydrogenating) aldols is used as crude 1,3-butanediol will be mainly described. In addition, the step of reducing (hydrogenating) aldols may be referred to as a "hydrogenation step."

[0142] The aldols used as a raw material in the hydrogenation step are not particularly limited as long as they are compounds that can be converted to 1,3-butanediol by hydrogen reduction. Examples of the raw aldols include aldol, its cyclic dimer, dimeric metahydroxybutyraldehyde (paraldol), 2,6-dimethyl-1,3-dioxane-4-ol (aldoxane), a cyclic trimer of acetaldehyde, and mixtures thereof.

[0143] The method for producing aldols (e.g., aldol and dimer-m-hydroxybutyraldehyde) is not particularly limited. For example, they can be obtained by an aldol condensation reaction of acetaldehyde in the presence of a basic catalyst, or by thermal decomposition of 2,6-dimethyl-1,3-dioxane-4-ol. It should be noted that the process of producing aldols is sometimes referred to as an "aldol production process" or an "acetaldehyde polymerization process."

[0144] Alternatively, the crude reaction solution containing aldols obtained by the above-mentioned reaction may be neutralized with acid to produce 1,3-butanediol. In addition to aldols, such a crude reaction solution may also contain acetaldehyde (AD), crotonaldehyde (CR), other aldehyde components, low boiling point substances, high boiling point substances such as aldehyde dimers or trimers, water, salt, etc. It should be noted that in this specification, compounds with a boiling point lower than that of 1,3-butanediol are sometimes referred to as "low boiling point substances" or "low boiling point substances", and compounds with a boiling point higher than that of 1,3-butanediol are sometimes referred to as "high boiling point substances" or "high boiling point substances".

[0145] The above-mentioned reaction crude liquid that comprises the aldols can also be used to implement pre-treatments such as dealcoholization distillation, dehydration distillation, desalination, alkali treatment and dealkalization treatment, decontamination as required to remove the material of by-products such as unreacted acetaldehyde, crotonaldehyde. As the method for pre-treatment, distillation, adsorption, ion exchange, heating high boiling point physicochemical reaction, decomposition etc. can be enumerated. Distillation can use various distillation methods such as decompression, normal pressure, pressurization, azeotropic, extraction, reaction. Particularly, preferably single evaporation, distillation, hydrogenation are implemented to the reaction crude liquid that comprises the aldols, after having removed aldehydes such as acetaldehyde, crotonaldehyde, the hydrogenation process is implemented.

[0146] The content of aldols in the hydrogenation raw material is not particularly limited, but is, for example, 30% by weight or more (e.g., 30% to 99% by weight), more preferably 40% by weight or more (e.g., 40% to 98% by weight), 50% by weight or more (e.g., 50% to 97% by weight), or 60% by weight or more (e.g., 60% to 95% by weight), further preferably 65% ​​to 90% by weight, particularly preferably 70% to 90% by weight, and most preferably 75% to 90% by weight. When the content of aldols is within the above range, there is a tendency for impurities contained in the crude reaction liquid containing 1,3-butanediol (crude 1,3-butanediol) to be reduced.

[0147] The hydrogenation raw material may contain water or not contain water, but from the viewpoint of the purity of the 1,3-butanediol product, it is preferably water-containing. The water content in the hydrogenation raw material is not particularly limited, for example, preferably 2% by weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, and particularly preferably 15% by weight or more. It should be noted that its upper limit may also be, for example, 90% by weight, 80% by weight, 70% by weight, 60% by weight, 50% by weight, 40% by weight, 30% by weight or 20% by weight. When the water content is within the above range, the acetal body of 1,3-butanediol and aldol contained in the obtained crude 1,3-butanediol is reduced, so there is a tendency for the purity of the finally obtained 1,3-butanediol product to become higher. The reason is that by including a certain degree of water in the hydrogenation raw material, the above-mentioned acetal body is hydrolyzed to become 1,3-butanediol, and the symbiotic aldol is reduced to become 1,3-butanediol.

[0148] As a hydrogenation catalyst, for example, Raney nickel etc. can be cited. The hydrogenation catalyst can be used in a suspended state or filled into a reaction vessel for use. The amount of the hydrogenation catalyst used is not particularly limited, but relative to 100 parts by weight of the hydrogenation raw material, for example, it is preferably 1 part by weight to 30 parts by weight, more preferably 4 parts by weight to 25 parts by weight, further preferably 8 parts by weight to 20 parts by weight, and particularly preferably 12 parts by weight to 18 parts by weight. The amount of hydrogen used for the reduction reaction is not particularly limited, but relative to 100 parts by weight of the hydrogenation raw material, for example, it is preferably 0.5 parts by weight to 40 parts by weight, more preferably 1 part by weight to 30 parts by weight, further preferably 4 parts by weight to 20 parts by weight, and particularly preferably 8 parts by weight to 12 parts by weight. The pressure (total pressure; gauge pressure) in the reaction system during the reduction reaction is not particularly limited, for example, it is 9MPa to 70MPa, and preferably 10MPa to 40MPa. The hydrogen pressure (hydrogen partial pressure) in the reaction system is not particularly limited, for example, 7MPa~60MPa, preferably 10MPa~30MPa. It should be noted that, from the viewpoint of reducing reducing substances such as acetaldehyde and crotonaldehyde, the hydrogen pressure in the reaction system can be increased, preferably more than 10MPa, or 100MPa. The reaction temperature in the reduction reaction is not particularly limited, for example, 40°C~150°C, preferably 50°C~140°C, more preferably 60°C~130°C. The reaction time (residence time) in the reduction reaction is not particularly limited, for example, 10 minutes~500 minutes, preferably 20 minutes~400 minutes, more preferably 30 minutes~300 minutes, further preferably 50 minutes~280 minutes, particularly preferably 80 minutes~250 minutes. This reaction can be carried out by any of batch, semi-batch or continuous methods.

[0149] The crude 1,3-butanediol obtained in this manner contains low-boiling-point substances (low-boiling-point compounds) with unsaturated bonds, such as acetaldehyde (AD), butyraldehyde, crotonaldehyde (CR), acetone, and methyl vinyl ketone; their condensates; condensates of 1,3-butanediol and these low-boiling-point substances (for example, acetals of 1,3-butanediol and aldol); alcohols such as ethanol, isopropanol, and butanol; water (solvent, etc.); salts generated by neutralization treatment, etc.; and catalysts (when used in a suspended state). By removing these impurities in the purification process, a 1,3-butanediol product (purified 1,3-butanediol) can be obtained.

[0150] [Purification of crude 1,3-butanediol]

[0151] Production method 1 of the present disclosure comprises at least a dehydration step for removing water by distillation, a high-boiling-point removal step (high-boiling-point distillation step) for removing high-boiling-point components by distillation, and a product distillation step for obtaining purified 1,3-butanediol. Production method 2 of the present disclosure comprises at least a dehydration step for removing water by distillation, and a high-boiling-point removal step (high-boiling-point distillation step) for removing high-boiling-point components by distillation.

[0152] In the manufacturing method disclosed herein, the order of the dehydration step and the high-boiling-point removal step is not limited. In the manufacturing method 1 disclosed herein, the dehydration step and the high-boiling-point removal step are both provided before the product distillation step. In the manufacturing method disclosed herein, in addition to these steps, it may also include: a desalination step, an alkali reaction step (alkali treatment step), and a dealkalization step. In addition, a catalyst separation step, a neutralization step using alkali, and a dealcoholization step (low-boiling-point removal step) may also be provided before the dehydration step. The steps may be carried out in the order described, and except that the dealkalization step is provided after the alkali reaction step, the order of the steps may also be appropriately changed. For example, the dealcoholization step (low-boiling-point removal step), the desalination step, the alkali reaction step, and the dealkalization step may be provided at appropriate locations, but are generally provided after the hydrogenation step. It should be noted that, among the above-mentioned steps, the catalyst separation step, the neutralization step using alkali, the dealcoholization step (low-boiling-point removal step), the desalination step, the alkali reaction step, and the dealkalization step may be provided as needed, or may not be provided.

[0153] Figure 1This is a flow chart of an apparatus representing an example of an implementation scheme of the method for producing 1,3-butanediol disclosed herein. A is a dehydration tower, which is related to the dehydration process. B is a desalination tower, which is related to the desalination process. C is a high-boiling-point substance removal distillation tower (high-boiling-point substance removal tower), which is related to the high-boiling-point substance removal distillation process (high-boiling-point substance removal process). D is an alkali reactor, which is related to the alkali reaction process. E is a dealkalization tower, which is related to the dealkalization process. F is a product distillation tower (product tower), which is related to the product distillation process. A-1, B-1, C-1, E-1, and F-1 are condensers. A-2, C-2, and F-2 are reboilers. Below, this flow chart is used to illustrate an example of an implementation scheme of the method for producing 1,3-butanediol disclosed herein.

[0154] The crude 1,3-butanediol (corresponding to "X-1") obtained by hydrogenation of the raw material is supplied to the dehydration column A. The crude 1,3-butanediol (corresponding to "X-1") may be supplied to the dehydration column A after undergoing a dealcoholization step (distillation step using a dealcoholization column) to remove alcohols such as ethanol and low-boiling-point substances.

[0155] In the production method of the present disclosure, in the dehydration tower A used in the dehydration step, for example, a charge liquid containing 1,3-butanediol and water is distilled, and a liquid (equivalent to 1,3-butanediol) in which a low-boiling-point component containing water is concentrated is distilled from the upper portion of the charge section (preferably the top of the tower). Figure 1 In addition, a crude 1,3-butanediol stream containing 1,3-butanediol is obtained from the lower portion of the charging section (preferably the bottom of the column).

[0156] Dehydration tower A and other distillation towers for separating 1,3-butanediol can use, for example, perforated plate towers and bubble cap towers, but towers packed with products such as Sulzer Packings and Mellapak (both trade names of Sumitomo Heavy Industries, Ltd.) are more preferred, as they offer low pressure drop. This is because 1,3-butanediol and trace amounts of impurities undergo thermal decomposition at high temperatures (e.g., 150°C or higher), generating low-boiling-point substances that are coloring components, thereby lowering the distillation temperature. A long thermal history (residence time) of 1,3-butanediol also has a similar effect. Therefore, the reboiler used is preferably one with a short residence time for the process-side fluid, such as a natural falling film evaporator or a forced stirring thin-film evaporator.

[0157] The theoretical number of stages in the dehydration column A is, for example, 1 to 100, preferably 2 to 80, 3 to 80, 4 to 60, 5 to 40, 6 to 30, or 7 to 20, and more preferably 8 to 15. The feed liquid is supplied downward from the top of the column, for example, at 10% to 90%, preferably 20% to 80%, more preferably 30% to 70%, and even more preferably 40% to 60% of the column height. During distillation in the dehydration column A, the pressure (absolute pressure) at the top of the column is, for example, 101 kPa or less, preferably 0.1 kPa to 90 kPa, more preferably 0.5 kPa to 70 kPa, even more preferably 1 kPa to 50 kPa, 2 kPa to 30 kPa, or 3 kPa to 20 kPa, and particularly preferably 4 kPa to 10 kPa. The distillation in the dehydration column A may be performed under pressure. In this case, the pressure (gauge pressure) at the top of the column may be, for example, 0.2 MPaG or less, or 0.1 MPaG or less.

[0158] The concentration of 1,3-butanediol in the feed liquid in dehydration column A is, for example, 9% by weight or greater, preferably 10% by weight or greater, more preferably 15% by weight or greater, still more preferably 20% by weight or greater, 25% by weight or greater, 30% by weight or greater, 35% by weight or greater, 40% by weight or greater, 45% by weight or greater, 50% by weight or greater, 55% by weight or greater, or 60% or greater, and particularly preferably 70% or greater. The upper limit of the concentration of 1,3-butanediol in the feed liquid in dehydration column A is, for example, 90% by weight, 85% by weight, or 80% by weight. However, considering the hydrogenation reaction in a step preceding the dehydration step, a higher water concentration in the feed liquid in dehydration column A may be preferable. Taking all of these into account, the concentration of 1,3-butanediol in the feed liquid in the dehydration tower A may be, for example, 1% by weight or more, 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. Furthermore, the concentration of 1,3-butanediol in the feed liquid in the dehydration tower A may be, for example, 99% by weight or less, 95% by weight or more, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, or 45% by weight or less. The concentration of 1,3-butanediol in the feed liquid in the dehydration column A can be adjusted to the above range by, for example, adjusting the reaction conditions in the hydrogenation step (e.g., the concentration of the aldols used as a raw material) and the distillation conditions of the dealcoholization column (low-boiling-water removal column) provided as needed before the dehydration column.

[0159] The above-mentioned 1,3-butanediol concentration (weight %) is the ratio of the 1,3-butanediol peak area to the total peak area (GC area %) in gas chromatography analysis under the following conditions, and is calculated using the following formula. The water concentration (weight %) in the feed liquid in dehydration column A is a value measured by the method described below (Karl Fischer method).

[0160] Concentration of 1,3-butanediol in the charge liquid in dehydration column A (weight %)

[0161] =(1-water concentration in the feed liquid in the dehydration column A (weight %) / 100)×GC area % of the above 1,3-butanediol

[0162] (Gas chromatography analysis conditions)

[0163] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0164] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0165] Sample introduction temperature: 250°C.

[0166] Carrier gas: Helium.

[0167] Column gas flow rate: 1 mL / min.

[0168] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0169] In the production method of the present disclosure, the acetaldehyde content in the charge liquid in the dehydration tower A is, for example, 1000 ppm or less, preferably 900 ppm or less, more preferably 800 ppm or less, 700 ppm or less, 600 ppm or less, or 500 ppm or less, further preferably 400 ppm or less, 300 ppm or less, 200 ppm or less, 155 ppm or less, or 140 ppm or less. It may also be 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less.

[0170] The content of crotonaldehyde in the charge liquid in the dehydration tower A is, for example, 400 ppm or less, preferably 300 ppm or less, more preferably 200 ppm or less, further preferably 150 ppm or less, 130 ppm or less, 117 ppm or less, or 100 ppm or less, and may be 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less.

[0171] The acetaldehyde content and crotonaldehyde content in the charge liquid in the dehydration tower A can be reduced by, for example, setting a dealcoholization tower (removal of low boiling tower) upstream of the dehydration tower A and adjusting the distillation conditions of the dealcoholization tower (removal of low boiling tower). For example, the acetaldehyde content and crotonaldehyde content in the charge liquid in the dehydration tower A can be reduced by increasing the reflux ratio, number of stages, and distillation rate of the dealcoholization tower (removal of low boiling tower). Moreover, the conditions of the hydrogenation reaction in the hydrogenation process can also be adjusted. When hydrogenation is fully carried out, the concentrations of acetaldehyde and crotonaldehyde can be reduced to below the detection limit, but this will result in unfavorable conditions such as increased reaction pressure or enlarged reaction tank.

[0172] It should be noted that the acetaldehyde content and crotonaldehyde content in the charge liquid in the dehydration column A can be quantified by GC-MS analysis (gas chromatography-mass spectrometry).

[0173] In the manufacturing method disclosed herein, the content of water in the charging liquid in the dehydration tower A is, for example, 90% by weight or less, 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, or 40% by weight or less, preferably 35% by weight or less, more preferably 30% by weight or less, and further preferably 25% by weight or less. The lower limit of the content of water in the charging liquid in the dehydration tower A is, for example, 15% by weight or 10% by weight. It should be noted that, considering the hydrogenation reaction in the hydrogenation process, the solubility and dispersion of hydrogen in the liquid with high water concentration and low viscosity increase, so it is conducive to the hydrogenation reaction. The content of water in the charging liquid in the dehydration tower A can be reduced by, for example, setting a dealcoholization tower (removal of low boiling tower) upstream of the dehydration tower A and adjusting the distillation conditions of the dealcoholization tower (removal of low boiling tower). For example, the water content in the feed liquid in the dehydration column A can be reduced by increasing the reflux ratio, number of stages, and distillation rate of the dealcoholization column (low-boiling removal column). It should be noted that the water content in the feed liquid in the dehydration column A can be quantified using a Karl Fischer moisture analyzer.

[0174] In the production method disclosed herein, the content of low-boiling components (excluding water) in the feed liquid to dehydration tower A is, for example, 20% or less, preferably 10% or less, more preferably 8% or less, even more preferably 5% or less, particularly preferably 3% or less or 2% or less, and may also be 1% or less, 0.5% or less, or 0.1% or less. The content of low-boiling components (also referred to as "low boiling substances" or "low boiling substances") excluding water in the feed liquid to dehydration tower A is the ratio (area %) of the total area of ​​peaks with a shorter retention time than the 1,3-butanediol peak in gas chromatography analysis under the above-described conditions. The content of low-boiling components (excluding water) in the feed liquid to dehydration tower A can be reduced, for example, by installing a dealcoholization tower (low boiling point removal tower) upstream of dehydration tower A and adjusting the distillation conditions of the dealcoholization tower (low boiling point removal tower). For example, the concentration of low-boiling components (excluding water) in the feed liquid in the dehydration column A can be reduced by increasing the reflux ratio, number of stages, or distillation rate of the dealcoholization column (low-boiling removal column). Furthermore, the concentration of low-boiling components (excluding water) in the feed liquid in the dehydration column A can also be reduced by, for example, adjusting the reaction conditions (e.g., reaction temperature) in the hydrogenation step.

[0175] The content of high-boiling-point components in the feed liquid to dehydration column A is, for example, 20% or less, preferably 10% or less, more preferably 7% or less, 4% or less, 3% or less, or 2% or less, further preferably 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less, and particularly preferably 0.01% or less. The content of high-boiling-point components in the feed liquid to dehydration column A can be adjusted, for example, by adjusting the reaction conditions (e.g., reaction temperature) during the hydrogenation step. The content of high-boiling-point components in the feed liquid to dehydration column A is the ratio (area %) of the total area of ​​peaks with a longer retention time than the 1,3BG peak, relative to the total peak area, as determined by gas chromatography analysis under the aforementioned conditions.

[0176] In the production method of the present disclosure, from the viewpoint of reducing the content of low-boiling substances (including water) in the crude 1,3-butanediol stream containing 1,3-butanediol withdrawn from the lower portion of the charging section of the dehydration column A (preferably the column bottom), the reflux ratio in the dehydration column A [dehydration column reflux amount / dehydration column distillate amount (amount discharged to the outside of the distillation column)] is, for example, greater than 0.3, preferably 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 15 or more, 20 or more, or 25 or more, and more preferably 30 or more (e.g., 40 or more). In particular, in the production method 2 of the present disclosure, the reflux ratio in the dehydration tower A is preferably 10 or greater, more preferably 20 or greater, even more preferably 30 or greater, and particularly preferably 50 or greater. From the perspective of energy cost, the upper limit of the reflux ratio is, for example, 100, preferably 50. It should be noted that when the theoretical number of stages of the dehydration tower A is large, sufficient separation can be achieved even if the reflux ratio is 10 or 20 or less.

[0177] In the production method disclosed herein, the distillation rate in dehydration tower A can be appropriately set depending on the water concentration in the feed liquid in dehydration tower A. The distillation rate is preferably a sufficient distillation rate to distill off all the water in the feed liquid. For example, when the water concentration in the feed liquid in dehydration tower A is X weight %, the distillation rate in dehydration tower A is preferably set to X weight % or higher. Thus, the distillation rate in dehydration tower A is, for example, 95 weight % or lower, 90 weight % or lower, 85 weight % or lower, 80 weight % or lower, 75 weight % or lower, 70 weight % or lower, 65 weight % or lower, 60 weight % or lower, 55 weight % or lower, 50 weight % or lower, 45 weight % or lower, 40 weight % or lower, 35 weight % or lower, 30 weight % or lower, 25 weight % or lower, 20 weight % or lower, 15 weight % or lower, 10 weight % or lower, or 5 weight % or lower. The distillation rate is the ratio (weight %) of the amount of liquid extracted from the upper portion of the charging section of the dehydration column A (e.g., the top) to the amount of material loaded in the dehydration column A.

[0178] In the production method disclosed herein, the 1,3BG recovery rate in the dehydration tower A is, for example, 99.3% or higher. In this specification, the 1,3BG recovery rate in the dehydration tower A is a value (%) calculated using the following formula.

[0179] {1 - [1,3BG concentration in distillate (weight %) × (distillate amount (parts) - recycled amount (parts))] / (1,3BG concentration in charge liquid (weight %) × charge amount (parts))} × 100. It should be noted that low-boiling and high-boiling substances may be hydrolyzed by water to produce 1,3BG, while high-boiling substances may also be produced by polymerization of 1,3BG. Furthermore, trace amounts of impurities may be generated and lost, so the material balance in the dehydration column may not always be achieved. This situation can also occur in other distillation columns such as the dealcoholization column (low-boiling removal column), the high-boiling removal column, and the product column.

[0180] Next, the crude 1,3-butanediol stream containing 1,3-butanediol withdrawn from the lower portion of the charging section of dehydration column A (preferably the bottom portion) is fed to demineralization column B. In demineralization column B, a desalted crude 1,3-butanediol stream is obtained from the top of the column by distillation, while salts, high-boiling substances, and the like are discharged from the bottom portion as a residue. The residue rate (%) of demineralization column B [(amount of demineralization column residue (parts) / amount of demineralization column charge (parts)) × 100] is, for example, 0.1% to 40% by weight, preferably 1% to 35% by weight, more preferably 2% to 30% by weight, even more preferably 3% to 25% by weight, particularly preferably 5% to 20% by weight, and may also be 7% to 15% by weight. It should be noted that at least a portion of the residue from the demineralization column may be reused in a process prior to the desalination step.

[0181] The desalted crude 1,3-butanediol stream is fed to the high-boiling removal column C. In the high-boiling removal column C, high-boiling components (high boilers) are discharged from the lower portion of the charging section (preferably from the bottom of the column). Meanwhile, a crude 1,3-butanediol stream (1,3-butanediol of further improved purity) from which high boilers have been removed is obtained from the upper portion of the charging section.

[0182] As the high-boiling tower C, for example, a porous plate tower, a bubble cap tower, etc. can be used, but a packed tower with low pressure loss such as Sulzer Packings or Mellapak (both are trade names of Sumitomo Heavy Industries, Ltd.) is more preferable. The reason is that 1,3-butanediol and trace impurities are thermally decomposed at high temperatures (for example, above 150°C) to produce low-boiling substances as coloring components, thereby lowering the distillation temperature. In addition, the same influence is also exerted when the thermal history (residence time) of 1,3-butanediol is long. Therefore, the reboiler used is preferably one with a short residence time of the process side fluid, for example, a thin film evaporator such as a natural falling film evaporator or a forced stirring thin film evaporator is preferred.

[0183] As the number of stages of the high-boiling component removal column C, the number of theoretical stages is, for example, 1 to 100 stages, preferably 2 to 90 stages, more preferably 3 to 80 stages, further preferably 4 to 70 stages, 5 to 60 stages, 8 to 50 stages, or 10 to 40 stages, and particularly preferably 15 to 30 stages. The supply position of the charge liquid is a position that is, for example, 10% to 90% of the height of the column from the top of the high-boiling component removal column, preferably 20% to 80%, more preferably 30 stages to 70 stages, and further preferably 40% to 60%. In the distillation in the high-boiling component removal column C, the pressure at the top (absolute pressure) is, for example, 0.01 kPa to 50 kPa, preferably 0.1 kPa to 30 kPa, more preferably 0.3 kPa to 20 kPa, and further preferably 0.5 kPa to 10 kPa.

[0184] In the production method 1 of the present disclosure, the concentration of 3BG in the charge liquid in the high-boiling component removal column C is, for example, 95% or more, preferably 96% or more (for example, 96.7% or more), more preferably 97% or more, further preferably 98% or more, and particularly preferably 99% or more. In the production method 2 of the present disclosure, the concentration of 1,3BG in the charge liquid in the high-boiling component removal column C is 96.7% or more, preferably 97% or more, more preferably 98% or more, and further preferably 99% or more. The concentration of 1,3BG in the charge liquid in the high-boiling component removal column C can be increased by adjusting the distillation conditions of the dehydration column A and the desalination column B. For example, the concentration of 1,3BG in the charge liquid in the high-boiling component removal column C can be increased by increasing the reflux ratio of the dehydration column A or increasing the kettle liquid ratio of the desalination column B. Note that the concentration of 1,3BG described above is the proportion of the area of the peak of 1,3BG to the total peak area (area %) in gas chromatography analysis (GC analysis) under the following conditions.

[0185] (Gas chromatography analysis conditions)

[0186] Analysis column: column with dimethylpolysiloxane as stationary phase (membrane thickness 1.0 μm x length 30 m x inner diameter 0.25 mm).

[0187] Temperature rising conditions: temperature was raised at 5°C / min from 80°C to 120°C, then raised at 2°C / min to 160°C and maintained for 2 minutes. Further, temperature was raised at 10°C / min to 230°C and maintained at 230°C for 18 minutes.

[0188] Sample introduction temperature: 250°C.

[0189] Carrier gas: helium.

[0190] Column gas flow rate: 1 mL / min.

[0191] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0192] The content of high-boiling-point components in the feed liquid to the high-boiling column C is, for example, 4% or less, preferably 3% or less, more preferably 2% or less, further preferably 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less, and particularly preferably 0.01% or less. In particular, in the production method 2 of the present disclosure, the content of high-boiling-point components in the feed liquid to the high-boiling column C is preferably 3% or less, more preferably 2% or less, further preferably 1.5% or less, 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less, and particularly preferably 0.01% or less. The content of high-boiling-point components in the feed liquid to the high-boiling column C can be reduced by adjusting the distillation conditions of the demineralization column B. For example, the content of high-boiling-point components in the feed liquid to the high-boiling column C can be reduced by increasing the stillage rate of the demineralization column B. The content of high boiling point components in the feed liquid in the high boiling point removal column C is the ratio (area %) of the total area of ​​peaks having a longer retention time than the 1,3BG peak to the total peak area in the gas chromatography analysis under the above conditions.

[0193] In the production method disclosed herein, the acetaldehyde content in the charge liquid in the high-boiling column C is, for example, 500 ppm or less, preferably 205 ppm or less (e.g., 200 ppm or less), more preferably 100 ppm or less, further preferably 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less, particularly preferably 5 ppm or less, and may be less than 2 ppm or less than 1 ppm. The crotonaldehyde content in the charge liquid in the high-boiling column C is, for example, 200 ppm or less, preferably 110 ppm or less, more preferably 100 ppm or less, further preferably 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, or 3 ppm or less, particularly preferably 2 ppm or less, and may be less than 1 ppm. The acetaldehyde content and crotonaldehyde content in the charge liquid of the high-boiling tower C can be reduced by, for example, setting a dealcoholization tower (low-boiling tower) and a dehydration tower upstream of the high-boiling tower C and adjusting the distillation conditions of the dealcoholization tower (low-boiling tower) and the dehydration tower. For example, the acetaldehyde content and crotonaldehyde content in the charge liquid of the high-boiling tower C can be reduced by increasing the reflux ratio, number of stages and distillation rate of the dealcoholization tower (low-boiling tower) and the dehydration tower. It should be noted that the acetaldehyde content and crotonaldehyde content in the charge liquid of the high-boiling tower C can be quantified by GC-MS analysis (gas chromatography-mass spectrometry).

[0194] In the production method disclosed herein, the water content in the feed liquid in the high-boiling column C is, for example, 3% by weight or less, preferably 2% by weight or less, more preferably 1.2% by weight or less, further preferably 1.1% by weight or less, 1.0% by weight or less, 0.95% by weight or less, 0.9% by weight or less, 0.8% by weight or less, 0.7% by weight or less, 0.6% by weight or less, 0.5% by weight or less, 0.4% by weight or less, 0.3% by weight or less, or 0.2% by weight or less, and particularly preferably 0.1% by weight or less. The water content in the feed liquid in the high-boiling column C can be reduced by adjusting the distillation conditions of the dehydration column A. For example, the water concentration in the feed liquid in the high-boiling column C can be reduced by increasing the reflux ratio, number of stages, or distillation rate of the dehydration column A. It should be noted that the water content in the feed liquid in the high-boiling column CF can be quantified using a Karl Fischer titrator. It should be noted that in the production method 2 of the present disclosure, the water content in the charge liquid in the high boiling point removal column C is 3 wt% or less, preferably 2 wt% or less, 1.2 wt% or less, 0.4 wt% or less, 0.3 wt% or less, or 0.2 wt% or less, and particularly preferably 0.1 wt% or less, 0.05 wt% or less, or 0.03 wt% or less.

[0195] In the production method disclosed herein, the content of low-boiling components (excluding water) in the feed liquid to the high-boiling removal column C is, for example, 1.8% or less, preferably 1.6% or less, more preferably 1.4% or less, further preferably 1.2% or less, 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less, and particularly preferably 0.1% or less. The content of low-boiling components (also referred to as "low boiling substances" or "low boiling substances") excluding water in the feed liquid to the high-boiling removal column C is the ratio (area %) of the total area of ​​peaks having a shorter retention time than the 1,3-butanediol peak to the total peak area in gas chromatography analysis under the above-described conditions. The content of low-boiling-point components (excluding water) in the feed liquid in the high-boiling-point removal column C can be reduced, for example, by installing a dealcoholization column (low-boiling-point removal column) upstream of the high-boiling-point removal column C and adjusting the distillation conditions of the dealcoholization column (low-boiling-point removal column). For example, the concentration of low-boiling-point components (excluding water) in the feed liquid in the high-boiling-point removal column C can be reduced by increasing the reflux ratio, number of stages, and distillation rate of the dealcoholization column (low-boiling-point removal column).

[0196] In the production method disclosed herein, from the viewpoint of lowering the dry point of the 1,3-butanediol product, the reflux ratio in the high-boiling column C [high-boiling column reflux rate / high-boiling column distillate rate (rate discharged to the outside of the distillation column)] is 0.03 or more, preferably 0.05 or more, more preferably 0.1 or more, further preferably 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.2 or more, 1.5 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 10 or more, and particularly preferably 20 or more. In particular, in the production method 2 of the present disclosure, the reflux ratio in the high boiling point removal column C is preferably 0.1 or higher, more preferably 0.2 or higher, 0.3 or higher, 0.4 or higher, 0.5 or higher, 0.6 or higher, 0.7 or higher, 0.8 or higher, 0.9 or higher, 1 or higher, 1.2 or higher, 1.5 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher, or 10 or higher, and particularly preferably 20 or higher. Note that, from the perspective of energy cost, the upper limit of the reflux ratio is, for example, 100, preferably 50. When the theoretical number of stages of the high boiling point removal column C is large, sufficient separation can be achieved even if the reflux ratio in the high boiling point removal column C is approximately 1 or lower.

[0197] In the production method of the present disclosure, by setting the reflux ratio in the high boiling point removal column C to the above range, high-purity 1,3BG having a very low content of high boiling point components and a low dry point can be produced at a high recovery rate.

[0198] In the production method disclosed herein, the stillage rate of the high-boiling column C is, for example, less than 30% by weight. However, when the stillage from the high-boiling column is further distilled in a distillation column to commercialize the depleted 1,3BG, this is not limiting. By limiting the final amount of high-boiling contents removed from the system to less than 30% by weight relative to the charge to the high-boiling column C, 1,3BG can be obtained at a high yield. The stillage rate refers to the ratio (in weight %) of the amount of liquid removed from the lower portion of the charge section (e.g., the bottom of the column) of the high-boiling column C (including the amount reused, if this liquid is reused in a previous step, as described below) relative to the charge to the high-boiling column C. It should be noted that, when this liquid is reused in a previous step, as the rate of discharge from the system decreases, the recovery rate of 1,3BG increases.

[0199] To improve the recovery rate of 1,3BG, the bottoms fraction of the high boiling column C is preferably 25% by weight or less, more preferably 20% by weight or less, even more preferably 15% by weight or less, 10% by weight or less, 7% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, or 2% by weight or less, and may be 1% by weight or less. Furthermore, from the perspective of lowering the dry point of the 1,3-butanediol product, the bottoms fraction of the high boiling column C is, for example, 0.01% by weight or more, preferably 0.1% by weight or more, 0.5% by weight or more, or 1% by weight or more, more preferably 2% by weight or more, 3% by weight or more, 4% by weight or more, 5% by weight or more, 6% by weight or more, 7% by weight or more, 8% by weight or more, 9% by weight or more, 10% by weight or more, or 15% by weight or more, and particularly preferably 20% by weight or more.

[0200] Alternatively, at least a portion ( Figure 1 The 1,3BG recovery rate can be increased by reusing at least a portion of the kettle liquid in the process prior to the high-boiling removal step (as indicated by the dashed arrow in the lower portion of the high-boiling removal column C). In this specification, the 1,3BG recovery rate in the high-boiling removal column C is the value (%) calculated using the following formula.

[0201] {1-[GC area % of 1,3BG in the kettle liquid × (amount of kettle liquid (parts) - amount of recycled (parts))] / (GC area % of 1,3BG in the charge liquid × charge amount (parts))}×100

[0202] It should be noted that low-boiling and high-boiling substances may be hydrolyzed by water to produce 1,3BG. On the other hand, high-boiling substances may be produced by polymerization of 1,3BG. There is also the generation and disappearance of trace impurities. Therefore, the material balance in the high-boiling removal column may not always be achieved.

[0203] The recovery rate of 1,3BG in the high boiling point removal column C is, for example, more than 80%, preferably 85% or more, more preferably 90% or more, further preferably 95% or more, and particularly preferably 99% or more.

[0204] Examples of the steps preceding the high-boiling-point removal step include an acetaldehyde polymerization step (acetaldehyde aldol condensation step), a reaction step (hydrogenation step), a dealcoholization step (low-boiling-point removal step), a dehydration step, and a desalination step. Of these, reuse in the acetaldehyde polymerization step (acetaldehyde aldol condensation step) is preferred because high-boiling-point substances can be hydrolyzed to produce 1,3BG. Furthermore, 1,3BG can sometimes be produced by hydrogenation reduction, and from this perspective, it can also be reused in the hydrogenation step.

[0205] The amount of reuse in the process before the high-boiling removal process of the still liquid can be appropriately selected within the range of the amount of the still liquid. The amount of reuse in the process before the high-boiling removal process of the still liquid is, for example, less than 30% by weight, preferably 25% by weight or less, relative to the amount of charge in the high-boiling removal column C. Note that the amount of reuse described above can also be set to 20% by weight or less, 15% by weight or less, 10% by weight or less, 7% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, or 1% by weight or less, relative to the amount of charge in the high-boiling removal column C. Furthermore, from the viewpoint of the 1,3BG recovery rate in the high-boiling removal column and the yield through the entire 1,3BG production process, the amount of reuse in the process before the high-boiling removal process of the still liquid is, for example, 0.01% by weight or more, preferably 0.1% by weight or more, further preferably 2% by weight or more, 3% by weight or more, 4% by weight or more, 5% by weight or more, 7% by weight or more, or 10% by weight or more, particularly preferably 20% by weight or more, relative to the amount of charge in the high-boiling removal column C. Note that even if not reused in the previous process, 1,3BG can be recovered at a high yield in the case of reducing the amount of still liquid to the limit.

[0206] The crude 1,3-butanediol stream taken out from the upper part of the charge section of the high-boiling removal column C can be directly made into a 1,3-butanediol product in the production method 2 of the present disclosure. Furthermore, the crude 1,3-butanediol stream taken out from the upper part of the charge section of the high-boiling removal column C can be subjected to alkali treatment in the alkali reactor D described later, evaporated (or distilled) in the alkali removal column E, and the overhead of the alkali removal column E can be made into a 1,3-butanediol product.

[0207] According to the production method 2 of the present disclosure, the acetaldehyde and crotonaldehyde content in the high-boiling removal column charge liquid is set to a specific range, and the reflux ratio of the high-boiling removal column is set to a specific range, and thus a colorless and odorless (or almost colorless and odorless), high-purity 1,3-butanediol product that is less likely to cause coloring, odor generation, and an increase in acid concentration over time even in a water-containing state can be industrially efficiently produced.

[0208] In the manufacturing method 1 disclosed in the present invention, the crude 1,3-butanediol stream taken out from the upper portion of the charging section of the high-boiling tower C is supplied to an alkali reactor (e.g., a flow-through tubular reactor) D, for example, for alkaline treatment. By alkali treatment, by-products contained in the crude 1,3-butanediol can be decomposed. The alkali can be added to the alkali reactor D or the piping upstream thereof. The amount of alkali added is, for example, 0.05% to 10% by weight, preferably 0.1% to 1.0% by weight, relative to the crude 1,3-butanediol stream to be alkali-treated. If the amount of alkali added exceeds 10% by weight, the alkali may precipitate in the distillation tower, piping, etc., causing blockage. In addition, a decomposition reaction of high-boiling-point compounds may occur, and by-products may be produced instead. When the amount of alkali added is less than 0.05% by weight, the effect of decomposing by-products is small.

[0209] There is no particular limitation on the alkali added to the alkali reactor D or its upstream piping, and for example, an alkali metal compound is preferred. Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, (heavy) sodium carbonate, and (heavy) potassium carbonate. In addition, as the alkali, a basic ion exchange resin can be used. As the alkali, sodium hydroxide and potassium hydroxide are preferred from the viewpoint of reducing the by-products contained in the final 1,3-butanediol product. The alkali can be added directly to the solid substance, but for the purpose of operation and promoting contact with the treated liquid, it is preferably added as an aqueous solution. It should be noted that the above-mentioned alkalis can be used alone or in combination of two or more.

[0210] The reaction temperature in the alkali reactor D is not particularly limited, but is preferably 90°C to 140°C, more preferably 110°C to 130°C. When the reaction temperature is lower than 90°C, a long reaction residence time is required, so the reactor capacity becomes large and uneconomical. If the reaction temperature exceeds 140°C, the coloration of the 1,3-butanediol product finally obtained may increase. The reaction residence time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 30 minutes. When the reaction residence time is less than 5 minutes, the reaction becomes insufficient, and the quality of the 1,3-butanediol product finally obtained may deteriorate. If the reaction residence time exceeds 120 minutes, a large reactor is required and the equipment cost becomes high, which is disadvantageous from an economic point of view.

[0211] After leaving the alkali reactor D, the crude reaction liquid flow is supplied to the dealkalization tower (for example, a thin film evaporator) E as needed, and the alkali and the like are removed from the bottom of the tower by evaporation. On the other hand, a dealkalized crude 1,3-butanediol flow (in the manufacturing method 2 disclosed herein, a 1,3-butanediol product) is obtained from the top of the dealkalization tower E. For the purpose of suppressing the thermal process of the process fluid, a natural falling film evaporator and a forced stirring thin film evaporator with a short residence time are suitable for the evaporator used in the dealkalization tower E. It should be noted that a demister can also be provided in the space above the loading position of the dealkalization tower (for example, a thin film evaporator) E to remove droplets of alkali and the like. In this way, alkali and the like can be prevented from mixing into the 1,3-butanediol product.

[0212] In the evaporator used in the dealkalization column E, evaporation is performed under reduced pressure at an absolute pressure of 20 kPa or less, preferably 0.5 kPa to 10 kPa, at the top of the column. The temperature of the evaporator is preferably 90°C to 120°C, for example. The crude 1,3-butanediol stream containing low-boiling substances distilled from the top of the column is supplied to the product distillation column (product column) F. It should be noted that, as described above, in the production method 2 of the present disclosure, the distillate from the top of the dealkalization column E (equivalent to E-1) can be converted into a 1,3-butanediol product.

[0213] It should be noted that the alkali reactor D and the dealkalization tower E may also be provided between the demineralization tower B and the high-boiling tower C, between the dehydration tower A and the demineralization tower B (in this case, the demineralization tower may also serve as the dealkalization tower), or before the dehydration tower A. In addition, the alkali reactor D and the dealkalization tower E may not be provided, and the alkali may be charged into the high-boiling tower charging line, or into the dehydration tower charging line, or added to the reaction liquid after hydrogenation [and then charged into the dealcoholization tower (low-boiling tower)] to perform the alkali treatment.

[0214] In the production method 1 of the present disclosure, in the product column F used in the product distillation step, a charge liquid having a 1,3-butanediol concentration of, for example, 97.6 area % or more as determined by GC analysis is distilled, and a liquid (equivalent to 1,3-butanediol) concentrated in low-boiling-point components is distilled from the upper portion of the charge section. Figure 1 "X-6"), extract 1,3-butanediol (equivalent to Figure 1 The extracted 1,3-butanediol can be made into 1,3-butanediol products.

[0215] As the product tower F, for example, a porous plate tower or a bubble cap tower can be used, but a packed tower with low pressure loss, such as Sulzer Packings or Mellapak (both are trade names of Sumitomo Heavy Industries, Ltd.), is more preferable. The reason for this is that 1,3-butanediol and trace impurities are thermally decomposed at high temperatures (for example, above 150°C) to produce low-boiling-point substances as coloring components, thereby lowering the distillation temperature. In addition, the same influence is also exerted when the thermal history (residence time) of 1,3-butanediol is long. Therefore, the reboiler used is preferably one with a short residence time of the process side fluid, for example, a thin film evaporator such as a natural falling film evaporator or a forced stirring thin film evaporator is preferred.

[0216] The theoretical number of stages in product column F is, for example, 1 to 100, preferably 2 to 90, 3 to 80, 4 to 70, 5 to 60, 8 to 50, or 10 to 40, and more preferably 15 to 30. The feed liquid is supplied downward from the top of the column, for example, at 10% to 90%, preferably 20% to 80%, more preferably 30% to 70%, and even more preferably 40% to 60% of the column height. During distillation in product distillation column F, the pressure (absolute pressure) at the top of the column is, for example, 20 kPa or less, preferably 0.1 kPa to 10 kPa, more preferably 0.3 kPa to 8 kPa, and even more preferably 0.5 kPa to 5 kPa.

[0217] exist Figure 1 Regarding the charging of the product tower F, the liquid after condensing the top vapor of the dealkalization tower E using the condenser E-1 can be fed, or the top vapor from the dealkalization tower E can be fed directly to the product tower F.

[0218] The concentration of 1,3-butanediol in the charge liquid (1,3-butanediol charge liquid) in product column F is 97.6% or more, preferably 97.8% or more, more preferably 98% or more, further preferably 98.2% or more (for example, 98.4% or more, 98.6% or more, or 98.8% or more), and particularly preferably 99% or more (for example, 99.1% or more, 99.2% or more, 99.3% or more, 99.4% or more, 99.5% or more, 99.6% or more, 99.7% or more, 99.8% or more, or 99.9% or more).

[0219] The concentration of 1,3-butanediol in the feed liquid in product column F can be increased, for example, by adjusting the distillation conditions of dehydration column A; by installing a dealcoholization column (low-boiling column) before dehydration column A and adjusting its distillation conditions; or by adjusting the distillation conditions of high-boiling column C. For example, the purity of 1,3-butanediol in the feed liquid in product column F can be increased by increasing the reflux ratio of the dealcoholization column (low-boiling column), dehydration column A, and / or high-boiling column C; or by increasing the number of stages.

[0220] The concentration of 1,3-butanediol in the feed liquid in the product column F is the ratio (area %) of the peak area of ​​1,3-butanediol to the total peak area in gas chromatography analysis under the following conditions.

[0221] (Gas chromatography analysis conditions)

[0222] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0223] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0224] Sample introduction temperature: 250°C.

[0225] Carrier gas: Helium.

[0226] Column gas flow rate: 1 mL / min.

[0227] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0228] In the production method 1 of the present disclosure, the acetaldehyde content in the charge liquid in the product column F is 500 ppm or less, preferably 205 ppm or less (e.g., 200 ppm or less), more preferably 150 ppm or less, further preferably 120 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less, particularly preferably 5 ppm or less, and may be less than 2 ppm. The crotonaldehyde content in the charge liquid in the product column F is 200 ppm or less, preferably 150 ppm or less, more preferably 130 ppm or less, further preferably 110 ppm or less, 100 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, or 3 ppm or less, particularly preferably 2 ppm or less, and may be less than 1 ppm. The acetaldehyde content and crotonaldehyde content in the charging liquid in product tower F can be reduced by, for example, arranging a dealcoholization tower (removing low boiling tower) and a dehydration tower in the upstream of product tower F, adjusting the distillation conditions of the dealcoholization tower (removing low boiling tower) and the dehydration tower. For example, the acetaldehyde content and crotonaldehyde content in the charging liquid in product tower F can be reduced by increasing the reflux ratio, the number of stages and the distillation rate of the dealcoholization tower (removing low boiling tower) and the dehydration tower. In addition, with regard to the acetaldehyde content and crotonaldehyde content in the charging liquid in product tower F, the acetaldehyde content and crotonaldehyde content in the charging liquid in product tower F can be reduced by increasing the reaction temperature, or lengthening the residence time or increasing the addition amount of alkali in the alkali reaction process. It should be noted that the acetaldehyde content and crotonaldehyde content in the charging liquid in product tower F can be quantitatively analyzed by GC-MS (gas chromatography-mass spectrometry).

[0229] In the production method 1 of the present disclosure, the water content in the charge liquid in product column F is 0.7 wt% or less, preferably 0.6 wt% or less, 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, or 0.2 wt% or less, and particularly preferably 0.1 wt% or less. The water content in the charge liquid in product column F can be reduced by adjusting the distillation conditions of the dehydration column A. For example, the water concentration in the charge liquid in product column F can be reduced by increasing the reflux ratio, number of stages, or distillation rate of the dehydration column A. It should be noted that the water content in the charge liquid in product column F can be quantified using a Karl Fischer titrator.

[0230] The content of low-boiling components (excluding water) in the feed liquid to product column F is, for example, 1.8% or less, preferably 1.6% or less, more preferably 1.4% or less, still more preferably 1.2% or less, 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less, and particularly preferably 0.1% or less. The content of low-boiling components (also referred to as "low boilers") excluding water in the feed liquid to product column F is the ratio (area %) of the total area of ​​peaks with a shorter retention time than the 1,3-butanediol peak in gas chromatography analysis under the above-described conditions to the total peak area. The content of low-boiling components (excluding water) in the feed liquid to product column F can be reduced, for example, by installing a dealcoholization column (low-boiling removal column) upstream of product column F and adjusting the distillation conditions of the dealcoholization column (low-boiling removal column). For example, the concentration of low-boiling components (excluding water) in the feed liquid in the product column F can be reduced by increasing the reflux ratio, number of stages, and distillation rate of the dealcoholization column (low-boiling removal column).

[0231] The content of high-boiling-point components (excluding water) in the feed liquid in product column F is, for example, 1.8% or less, preferably 1.6% or less, more preferably 1.4% or less, further preferably 1.2% or less, 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less, and particularly preferably 0.1% or less. The content of high-boiling-point components (also referred to as "high boiling substances" or "high boilers") excluding water in the feed liquid in product column F is the ratio (area %) of the total area of ​​peaks having a longer retention time than the 1,3-butanediol peak in gas chromatography analysis under the above-described conditions to the total peak area. The content of high-boiling-point components (excluding water) in the feed liquid in product column F can be reduced, for example, by adjusting the distillation conditions of the high-boiling column. For example, the concentration of high-boiling-point components (excluding water) in the feed liquid in the product column F can be reduced by increasing the reflux ratio, the number of stages, and the kettle liquid rate of the high-boiling-point removal column.

[0232] In the production method 1 of the present disclosure, from the viewpoint of increasing the initial distillation point of the 1,3-butanediol product, the reflux ratio [product column reflux amount / product column distillate amount (amount discharged to the outside of the distillation column)] in product column F is 0.3 or greater, preferably 0.4 or greater, more preferably 0.5 or greater, 1 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, 6 or greater, 7 or greater, 8 or greater, 9 or greater, 10 or greater, 20 or greater, or 50 or greater, and particularly preferably 400 or greater (e.g., 500 or greater). From the perspective of energy cost, the upper limit of the reflux ratio in product column F is, for example, 700 or 1000.

[0233] In the production method 1 of the present disclosure, from the perspective of improving the recovery rate of 1,3-butanediol, the distillation rate of the product column F is, for example, less than 30% by weight, preferably 29% by weight or less, more preferably 28% by weight or less, further preferably 27% by weight or less, 26% by weight or less, 25% by weight or less, 24% by weight or less, 23% by weight or less, 22% by weight or less, 21% by weight or less, 20% by weight or less, 19% by weight or less, 18% by weight or less, 17% by weight or less, 16% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, or 0.6% by weight or less, and particularly preferably 0.4% by weight or less. The distillation rate is the ratio (weight %) of the amount of liquid extracted from the upper portion of the charging section of the product column F (e.g., the top portion) to the outside of the distillation column (including the amount recycled in the case of recycling in a previous step described later) relative to the amount of liquid charged to the product column F.

[0234] Alternatively, at least a portion ( Figure 1 The distillate is then recycled (as indicated by the dotted arrow on the right side of the product column F) in a step preceding the product distillation step. Reusing at least a portion of the distillate in a step preceding the product distillation step improves the recovery rate of 1,3-butanediol.

[0235] Examples of the steps before the product distillation step include a dehydration step, a dealcoholization step (low boiling point removal step), etc. The dealcoholization step (low boiling point removal step) is preferably provided before the dehydration step.

[0236] The amount of distillate reused in the steps preceding the product distillation step can be appropriately selected within the range of the distillate amount. The amount of distillate reused in the steps preceding the product distillation step is, for example, less than 30% by weight relative to the charge to product column F. Furthermore, from the perspective of improving the 1,3BG recovery rate in the product column and the overall process yield, the amount of distillate reused in the steps preceding the product distillation step is, for example, 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 1.5% by weight or more, 2% by weight or more, 3% by weight or more, 4% by weight or more, 5% by weight or more, 7% by weight or more, or 10% by weight or more, and particularly preferably 20% by weight or more, relative to the charge to product column F.

[0237] In the production method 1 disclosed herein, by setting the contents of acetaldehyde and crotonaldehyde in the charge liquid in the product column F to below a specific value and setting the reflux ratio in the product column F to a specific range, a high-purity 1,3-butanediol product can be produced industrially and efficiently. The product is colorless and odorless (or almost colorless and odorless), is less likely to discolor or generate odor over time, and is less likely to increase in acid concentration over time even in a water-containing state.

[0238] The recovery rate of 1,3BG in the product column F is, for example, more than 80%, preferably 85% or more, more preferably 90% or more, further preferably 95% or more, and particularly preferably 99% or more.

[0239] In addition, in this specification, the recovery rate of 1,3BG in the product column F is a value (%) calculated|required by the following formula.

[0240] {1-[GC area % of 1,3BG in the distillate × (distillate amount (parts) - recycled amount (parts))] / (GC area % of 1,3BG in the charge liquid × charge amount (parts))} × 100. As described above, low-boiling-point substances and high-boiling-point substances may be hydrolyzed by water to produce 1,3BG. On the other hand, high-boiling-point substances may be produced by polymerization of 1,3BG. Therefore, the material balance in the product column may not always be achieved.

[0241] It should be noted that the various solutions disclosed in this specification can be combined with any other features disclosed in this specification. In addition, the various components and combinations of components in the various embodiments are examples, and appropriate additions, omissions, and other modifications can be made without departing from the scope of the present disclosure. The present disclosure is not limited by the embodiments but only by the claims.

[0242] Example

[0243] The present disclosure is further described below using examples, but the present disclosure is not limited to these examples. It should be noted that "parts" used in the examples refer to "parts by weight" unless otherwise specified. Gas chromatography analysis (GC analysis), determination of initial boiling point, and determination of water content were performed using the methods described below.

[0244] [Example 1]

[0245] use Figure 1 The method for producing 1,3-butanediol will be described.

[0246] A liquid-phase hydrogen reduction reactor was charged with 100 parts of a 30% by weight aldol solution (a mixed solution of 69 parts of aldol and 29 parts of water, containing a total of 2 parts of low-boiling and high-boiling impurities and less than 0.1 parts of sodium salt) containing 30% by weight of water as a raw material. 10 parts of hydrogen gas and 15 parts of Raney nickel as a catalyst were added. The reactor was maintained at 120°C and 10 MPa (gauge pressure) to carry out liquid-phase hydrogen reduction. After the catalyst was separated from the liquid after the reaction, it was neutralized with caustic soda to obtain crude 1,3-butanediol (1) containing low-boiling impurities and water.

[0247] It should be noted that the aldol solution containing 30% by weight of water used as a raw material was produced in the following manner [acetaldehyde polymerization step (acetaldehyde aldol condensation step)]: acetaldehyde and water were stirred at 30°C in the presence of 100 wtppm of NaOH for a residence time of 10 hours to reduce the acetaldehyde to a dilution.

[0248] The crude 1,3-butanediol (1) (equivalent to Figure 1 "X-1" in the dehydration tower A) was charged into the dehydration tower A. The concentration of 1,3-butanediol in the charge liquid in the dehydration tower A was 56 wt%, the concentration of water was 40 wt%, the content of acetaldehyde (AD) was 130 ppm, the content of crotonaldehyde (CR) was 89 ppm, and in the GC analysis described later, the total area ratio of the impurity peaks with a shorter retention time (RT) than that of 1,3-butanediol was 3%, and the total area ratio of the impurity peaks with a longer retention time than that of 1,3-butanediol was 1%. In the dehydration tower A, distillation was carried out under the conditions of a top pressure of 10 kPa (absolute pressure) and a reflux ratio of 1, and water was extracted from the top of the tower. With respect to 100 parts of the charge liquid, 43 parts (distillate) were discharged and removed to the outside of the system (equivalent to Figure 1 From the bottom of the column, the following crude 1,3-butanediol (2) was obtained: the concentration of 1,3-butanediol was 96.9 GC area %, the content of water was 0.9 wt %, the total area ratio of the impurity peaks with a shorter retention time than that of 1,3-butanediol in the GC analysis described later was 0.8%, the total area ratio of the peaks with a longer retention time than that of 1,3-butanediol was 2.3%, the acetaldehyde content was 18 ppm, and the crotonaldehyde content was 17 ppm.

[0249] Next, the crude 1,3-butanediol (2) is fed into the demineralization tower B. In the demineralization tower B, salts, high boiling point substances, and a portion of the 1,3-butanediol are discharged from the bottom of the tower as evaporation residue (equivalent to Figure 1 The amount of the evaporation residue discharged was 5 parts relative to 100 parts of the feed liquid. On the other hand, crude 1,3-butanediol (3) containing 1,3-butanediol, low-boiling substances, and a portion of high-boiling substances was obtained from the top of the column.

[0250] Next, the crude 1,3-butanediol (3) was fed into the high-boiling removal column C. In the high-boiling removal column C, distillation was carried out under the conditions of a top pressure of 5 kPa (absolute pressure) and a reflux ratio of 0.05, and high boiling point substances and a portion of 1,3-butanediol (equivalent to Figure 1 The amount of the column bottom discharge was 20 parts relative to 100 parts of the feed liquid. On the other hand, 80 parts of crude 1,3-butanediol (4) containing low-boiling substances was obtained as a distillate from the top of the column.

[0251] Next, crude 1,3-butanediol (4) was charged into the alkali reactor D. At this time, a 20 wt% aqueous caustic soda solution was added so that the concentration of caustic soda relative to the charged solution became 0.1 wt%. The reaction temperature in the alkali reactor D was maintained at 120°C, and the reaction was carried out with a residence time of 20 minutes.

[0252] Next, the crude reaction liquid from the alkali reactor D is fed into the dealkalization tower E. In the dealkalization tower E, caustic soda, high boiling point substances and a portion of 1,3-butanediol (relative to Figure 1 "X-5" in the column). The amount of discharge from the bottom of the column was 10 parts relative to 100 parts of the loading liquid. On the other hand, 90 parts of crude 1,3-butanediol (5) containing 1,3-butanediol and low-boiling-point substances were obtained from the top of the column. The crude 1,3-butanediol (5) containing 1,3-butanediol and low-boiling-point substances was subjected to moisture measurement, GC analysis and GC-MS analysis. The results showed that the moisture concentration was 1% by weight, the area ratio of 1,3-butanediol was 99%, the total area ratio of impurity peaks with a shorter retention time than 1,3-butanediol was 0.4%, the total area ratio of impurity peaks with a longer retention time than 1,3-butanediol was 0.6%, the acetaldehyde content was 20 ppm, and the crotonaldehyde content was 9 ppm.

[0253] Next, crude 1,3-butanediol (5) was charged into the product column F. In the product column F, 10 parts of low-boiling-point substances and a portion of 1,3-butanediol (equivalent to 100 parts of the charged liquid) were distilled from the top of the column. Figure 1 The reflux ratio (reflux amount / distillate amount) at this time was operated at 0.5, and 90 parts of 1,3-butanediol products (distillate amount was 10 parts) were obtained from the bottom of the tower (equivalent to Figure 2 in the .

[0254] The resulting 1,3-butanediol product was subjected to initial boiling point (IBP) and moisture content measurement, GC analysis, and GC-MS analysis. The results showed an IBP of 203.3°C, a dry point of 209°C, a moisture concentration of 0.2% by weight, an area fraction of 99.2% for 1,3-butanediol, a total area fraction of impurity peaks with shorter retention times than 1,3-butanediol of 0.08%, and a total area fraction of impurity peaks with longer retention times than 1,3-butanediol of 0.7%. The acetaldehyde content was 1.5 ppm, and the crotonaldehyde content was 0.9 ppm. The potassium permanganate test value was 35 minutes. The 1,3-butanediol recovery rate in product column F was 90%.

[0255] [Example 2]

[0256] The same procedures as in Example 1 were followed, except that the reflux ratio of dehydration column A was changed to 50. A 1,3-butanediol product was obtained from the bottom of product column F. It should be noted that the changed conditions in dehydration column A altered the composition of the dehydration column bottoms liquid, and the composition of the feed liquids in dehydration column C and product column F, respectively, resulting in changes in product quality.

[0257] The resulting 1,3-butanediol product was subjected to initial boiling point (IBP) and moisture content measurement, as well as GC and GC-MS analysis. The results showed an IBP of 206.7°C, a dry point of 208.9°C, a moisture concentration of 0.1% by weight, an area fraction of 99.3% for 1,3-butanediol, a total area fraction of impurity peaks with shorter retention times than 1,3-butanediol of 0.05%, and a total area fraction of impurity peaks with longer retention times than 1,3-butanediol of 0.7%. The acetaldehyde content was 0.7 ppm, and the crotonaldehyde content was 0.7 ppm. The potassium permanganate test value was 45 minutes. The 1,3-butanediol recovery rate in product column F was 90%.

[0258] [Examples 3 to 27]

[0259] Dehydration Column A, High Boiling Point Removal Column C, and Product Column F were operated under the conditions shown in Tables 1 and 2. Note that in Examples 4-22 and 24-27, the entire distillate from Product Column F was reused in the hydrogen reduction reactor. In Example 23, Product Column F was omitted, and the overhead distillate from Dealkalization Column E (with a demister installed in the space above the loading point) was used to produce the 1,3-butanediol product. The concentration of the caustic soda solution in the alkali reactor D was increased to 1.5 times, and the amount of caustic soda added was reduced to half that of Example 1 to minimize moisture increase caused by the alkali treatment. Note that excessively high alkali concentrations in the caustic soda solution can cause crystal precipitation, so heating to 40°C or above is preferred. The composition and physical properties of the overhead distillate from Dealkalization Column E are reported in the "Product Column F Bottom Liquid" column of Example 23 in Table 2. It should be noted that in Example 16, 8 parts of the 10 parts of the high-boiling tower bottom liquid were reused in the hydrogenation process, and 2 parts were discharged outside the system. In addition, in Example 25, the pressure of the hydrogenation reaction was reduced to 7MPaG (gauge pressure). Therefore, the acetaldehyde content and crotonaldehyde content in the dehydration tower charging liquid were high. In Example 26, the reflux ratio of the dehydration tower was reduced to 0.3, the purity of 1,3-butanediol in the product tower charging liquid was reduced, and the reflux ratio of the product tower was increased to 20. In Example 27, the pressure of the hydrogenation reaction was increased to 40MPaG (gauge pressure) (the remaining conditions were the same as in Example 18).

[0260] [Comparative Example 1]

[0261] The same method as in Example 1 was used, except that the reflux ratio of dehydration column A was changed to 0.5 and the distillate output was changed to 42 parts; the reflux ratio of high-boiling column C was changed to 0.02; and the reflux ratio of product column F was changed to 0.05 and the distillate output was changed to 20 parts. 80 parts of 1,3-butanediol product were obtained from the bottom of product column F. The resulting 1,3-butanediol product had an initial boiling point of 193.2°C, a dry point of 210.3°C, and a water concentration of 0.6% by weight. The area fraction of 1,3-butanediol was 98.3%, the total area fraction of impurity peaks with shorter retention times than 1,3-butanediol was 0.2%, and the total area fraction of impurity peaks with longer retention times than 1,3-butanediol was 1.5%. The acetaldehyde content was 5 ppm, and the crotonaldehyde content was 4 ppm. The potassium permanganate test value was 0 minutes. The 1,3-butanediol recovery rate in product column F was 80%.

[0262] [Comparative Example 2]

[0263] The same method as in Example 1 was used to obtain 80 parts of a 1,3-butanediol product from the bottom of product column F, except that the charge composition of dehydration column A was changed to 0.5, the distillate yield was changed to 32 parts, the reflux ratio of high-boiling column C was changed to 0.02, and the reflux ratio of product column F was changed to 0.05, and the distillate yield was changed to 20 parts. The resulting 1,3-butanediol product had an initial boiling point of 199.0°C, a dry point of 210.1°C, a water concentration of 0.4% by weight, an area fraction of 1,3-butanediol of 98.5%, a total area fraction of impurity peaks with shorter retention times than 1,3-butanediol of 0.1%, and a total area fraction of impurity peaks with longer retention times than 1,3-butanediol of 1.4%. The acetaldehyde content was 4 ppm, and the crotonaldehyde content was 2 ppm. The potassium permanganate test value was 5 minutes. The recovery rate of 1,3-butanediol in product column F was 80%.

[0264] [Comparative Example 3]

[0265] The same method as in Example 1 was used to obtain 70 parts of a 1,3-butanediol product from the bottom of product column F, except that the charge composition of dehydration column A was changed to 0.5, the distillate yield was changed to 32 parts, the reflux ratio of high-boiling column C was changed to 0.02, and the reflux ratio of product column F was changed to 0.05, and the distillate yield was changed to 30 parts. The 1,3-butanediol product had an initial boiling point of 203.0°C, a dry point of 210.2°C, and a water concentration of 0.2% by weight. The area fraction of 1,3-butanediol was 98.4%, the total area fraction of impurity peaks with shorter retention times than 1,3-butanediol was 0.1%, and the total area fraction of impurity peaks with longer retention times than 1,3-butanediol was 1.5%. The acetaldehyde content was 2 ppm, and the crotonaldehyde content was 1.3 ppm. The potassium permanganate test value was 30 minutes. The recovery rate of 1,3-butanediol in product column F was 70%.

[0266] [Comparative Example 4]

[0267] The same method as in Example 1 was used to obtain 80 parts of 1,3-butanediol product from the bottom of product column F, except that the charge composition of dehydration column A was changed to 23 parts of distillate, the reflux ratio of high-boiling column C was changed to 0.02, and the reflux ratio of product column F was changed to 0.1, resulting in a distillate of 20 parts. The 1,3-butanediol product had an initial boiling point of 203.1°C, a dry point of 209.5°C, and a water concentration of 0.2% by weight. The area fraction of 1,3-butanediol was 98.8%, the total area fraction of impurity peaks with shorter retention times than 1,3-butanediol was 0.1%, and the total area fraction of impurity peaks with longer retention times than 1,3-butanediol was 1.1%. The acetaldehyde content was 2 ppm, and the crotonaldehyde content was 1.3 ppm. The potassium permanganate test value was 30 minutes. The 1,3-butanediol recovery rate from product column F was 80%.

[0268] [Gas chromatography analysis]

[0269] The gas chromatography analysis of the target 1,3-butanediol product was carried out under the following conditions. The gas chromatography analysis spectrum of the 1,3-butanediol product in Example 12 is shown in FIG. Figure 3 In addition, the gas chromatography analysis spectrum of the 1,3-butanediol product in Comparative Example 2 is shown in ​ .

[0270] (Gas chromatography analysis conditions)

[0271] Analytical equipment: Shimadzu GC2010.

[0272] Analytical column: a column having a dimethylpolysiloxane stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm) (“Agilent J&W GC column-DB-1”, manufactured by Agilent Technologies, Inc.).

[0273] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0274] Sample introduction and temperature: split sample introduction method, 250°C.

[0275] Gas flow rate of the slit and carrier gas: 23 mL / min, helium.

[0276] Column gas flow rate and carrier gas: 1 mL / min, helium.

[0277] Detector and temperature: flame ionization detector (FID), 280°C.

[0278] Injection sample: 0.2 μL of 80 wt% 1,3-butanediol product aqueous solution.

[0279] [Determination of initial boiling point and drying point]

[0280] The test was conducted in accordance with the atmospheric distillation test method specified in JIS K2254 "Petroleum products - Distillation test methods".

[0281] [Determination of moisture]

[0282] The water content was determined using a Karl Fischer water titration apparatus.

[0283] [GC-MS analysis]

[0284] Analytical equipment: Agilent 6890A-GC / 5973A-MSD.

[0285] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0286] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0287] Sample introduction temperature: 250°C.

[0288] Carrier gas: Helium.

[0289] Column gas flow rate: 1 mL / min.

[0290] Ion source temperature: EI 230°C, CI 250°C.

[0291] Q-pole temperature: 150°C.

[0292] Sample: Provided directly for analysis.

[0293] [Potassium permanganate test]

[0294] In this specification, the potassium permanganate test value (PMT) is a value measured according to the procedure of the visual colorimetry method of JIS K1351 (1993).

[0295] [Coloration test 1 over time]

[0296] The 1,3-butanediol product was placed in a wide-mouth bottle, sealed with a stopper, and held in a thermostat set at 180°C for 3 hours. The Hazen color (APHA) of the 1,3-butanediol product after holding at 180°C for 3 hours was measured using a colorimeter ("ZE6000" manufactured by Nippon Denshoku Industries Co., Ltd.) using a quartz cell with a 10 mm optical path length. The Hazen color (APHA) of the 1,3-butanediol product before the test was also measured in the same manner.

[0297] [Coloration test 2 over time]

[0298] The 1,3-butanediol product was placed in a wide-mouth bottle, sealed with a stopper, and maintained in a thermostatic chamber set at 100°C for 75 days. The Hazen color (APHA) of the 1,3-butanediol product after 75 days at 100°C was measured using a colorimeter ("ZE6000" manufactured by Nippon Denshoku Industries Co., Ltd.) using a quartz cell with a 10 mm optical path length.

[0299] [Water Addition Heating Test (Acid Concentration Analysis)]

[0300] The 1,3-butanediol product under test was prepared as a 90 wt% aqueous solution and maintained at 100°C for one week. The sample was then analyzed for acid concentration using the following method. The 1,3-butanediol product before the test was also analyzed for acid concentration using the following method.

[0301] (Acid concentration analysis)

[0302] Measurements were made using a potentiometric titrator (AT-510, manufactured by Kyoto Denshi Kogyo). 50 g of the sample was diluted with 50 g of distilled water and titrated with 0.01 N sodium hydroxide solution from a burette while stirring until the automatic endpoint was reached. The acid concentration (acid content) in terms of acetic acid was then calculated using the following formula.

[0303] Acid concentration (weight %) = titration amount (ml) × F × A × (100 / sample amount (g)).

[0304] F: 1.0 (factor of 0.01N sodium hydroxide aqueous solution).

[0305] A: 0.0006 (the number of grams of acetic acid equivalent to 1 ml of sodium hydroxide aqueous solution).

[0306] [Odor test]

[0307] The 1,3-butanediol product (100 ml) to be tested was placed in a wide-mouth reagent bottle (content: 100 ml), sealed with a stopper, and allowed to stand at room temperature for a short period (approximately 120 minutes). The bottle was then unstopped and transferred to a 300 ml wide-mouth beaker. 100 ml of pure water was added to the bottle, making a total of 200 ml. The sample was shaken manually to mix, and the odor was quickly smelled and scored according to the following evaluation. The same odor test was also conducted on samples after undergoing the above-described Time-Dependent Coloration Test 1 and the above-described Water Addition and Heating Test.

[0308] 1: No smell is detected.

[0309] 2: Slightly smelly.

[0310] 3: The smell is clearly felt.

[0311] [Inspection of results]

[0312] The results of the comparative examples and examples are shown in Tables 1, 2, and 3.

[0313]

[0314]

[0315]

[0316]

[0317] [Table 3]

[0318]

[0319]

[0320] According to Comparative Example 1, Comparative Example 2, Example 1, Example 5, and Example 7, it can be seen that the lower the content of acetaldehyde, crotonaldehyde, and other impurities (quantitative limit 10 ppm) detected by gas chromatography; and the lower the content of methyl vinyl ketone, acetone, butyraldehyde, butyral, the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5) detected by GC-MS analysis, the better the long-term storage stability with respect to coloring, acid concentration, and odor.

[0321] The same applies to Examples 7, 12, and 18. However, according to Examples 12 and 18, reducing the contents of methyl vinyl ketone, acetone, butyraldehyde, aldol, and the compound represented by formula (1), which have lower boiling points than 1,3BG, as well as reducing the contents of the compound represented by formula (2), the compound represented by formula (3), the compound represented by formula (4), and the compound represented by formula (5), which have higher boiling points than 1,3BG, all had an effect on long-term stability. However, reducing not only the contents of these impurities but also the combined contents of acetaldehyde, crotonaldehyde, and other impurities (quantitative limit 10 ppm) detected by gas chromatography analysis was most effective for improving the long-term stability of the quality of the 1,3BG product. In Example 7, the stability of the product quality was significantly improved. It should be noted that, overall, there was no clear correlation between the contents of impurities other than 1,3BG detected by gas chromatography analysis (around the quantitative limit 10 ppm) and the contents of impurities less than 10 ppm, from methyl vinyl ketone to the compound represented by formula (5), detected by GC-MS analysis. This is considered to be the result of subtle changes in the concentration of each component due to the reaction conditions and the distillation conditions.

[0322] Example 24 is a case where the water content of the dehydration tower feed liquid is very high, but the tendency is the same as above. The relationship between the overall behavior of impurities and the APHA and acid concentration (acid content) shows the same tendency as Example 7.

[0323] Example 26 reduces the 1,3-butanediol concentration in the product column feed liquid. However, it can be seen that the quality of the 1,3BG product can be maintained as long as the reflux ratio of the product column is kept high.

[0324] Examples 18 and 27 show that by increasing the hydrogenation pressure to fully react unsaturated compounds such as aldehydes, olefins, and acetals in the reaction system, and further adjusting the distillation conditions in each distillation column, the quality of the 1,3BG product can be further improved.

[0325] As a summary of the above, the configuration of the present disclosure and its variations are supplementally described below.

[0326] [1] A 1,3-butanediol product, wherein at least one of the eight contents of methyl vinyl ketone, acetone, butyraldehyde, butyral, the compound represented by the following formula (1), the compound represented by the following formula (2), the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5) is less than 8 ppm (or less than 7 ppm, less than 6 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm, less than 1 ppm, or less than 0.5 ppm).

[0327]

[0328] [2] The 1,3-butanediol product according to [1], wherein two (or three, four, five, six, seven, or eight) of the eight contents of methyl vinyl ketone, acetone, butyraldehyde, butyral, the compound represented by the following formula (1), the compound represented by the following formula (2), the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5) are each less than 8 ppm (or less than 7 ppm, less than 6 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm, less than 1 ppm, or less than 0.5 ppm).

[0329] [3] The 1,3-butanediol product according to [1] or [2], wherein at least four (four, five, six, seven, or eight) of the eight contents of methyl vinyl ketone, acetone, butyraldehyde, aldol, the compound represented by the following formula (1), the compound represented by the following formula (2), the compound represented by the following formula (3), and the total content of the compound represented by the following formula (4) and the compound represented by the following formula (5) are each less than 8 ppm (or less than 7 ppm, less than 6 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm, less than 1 ppm, or less than 0.5 ppm).

[0330] [4] The 1,3-butanediol product according to any one of [1] to [3], wherein the sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butanediol, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4), and the content of the compound represented by formula (5) is less than 71 ppm (or, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 10 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0331] [5] The 1,3-butanediol product according to any one of [1] to [4], wherein the sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of aldol, and the content of the compound represented by formula (1) is less than 47 ppm (or, 40 ppm or less, 30 ppm or less, 25 ppm or less, 20 ppm or less, 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 10 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or less than 0.5 ppm), and the sum of the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4), and the content of the compound represented by formula (5) is less than 24 ppm (or, less than 20 ppm, less than 18 ppm, less than 16 ppm, less than 14 ppm, less than 13 ppm, less than 12 ppm, less than 11 ppm, less than 10 ppm, less than 9 ppm, less than 8 ppm, less than 7 ppm, less than 6 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm, less than 1 ppm, or less than 0.5 ppm).

[0332] [6] The 1,3-butanediol product according to any one of [1] to [5], wherein the content of at least butanediol is less than 8 ppm (or, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0333] [7] The 1,3-butanediol product according to any one of [1] to [6], wherein the content of at least the compound represented by formula (3) is less than 8 ppm (or, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0334] [8] The 1,3-butanediol product according to any one of [1] to [7], wherein the total content of methyl vinyl ketone, acetone, and butyraldehyde is 24 ppm or less (or 20 ppm or less, 18 ppm or less, 16 ppm or less, 14 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less).

[0335] [9] The 1,3-butanediol product according to any one of [1] to [8], wherein the total content of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (4), and the compound represented by formula (5) is 24 ppm or less.

[0336]

[10] The 1,3-butanediol product according to any one of [1] to [9], wherein the acetaldehyde content is less than 4 ppm (or, less than 2 ppm, 1.8 ppm or less, 1.7 ppm or less, 1.5 ppm or less, 1.4 ppn or less, 1.3 ppm or less, 1.2 ppm or less, 1.1 ppm or less, 1.0 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.3 ppm or less, or 0.2 ppm or less).

[0337]

[11] The 1,3-butanediol product according to any one of [1] to

[10] , wherein the crotonaldehyde content is less than 2 ppm (or less than 1.2 ppm, 1.0 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.4 ppm or less, 0.3 ppm or less, 0.2 ppm or less, or 0.1 ppm or less).

[0338]

[12] The 1,3-butanediol product according to any one of [1] to

[11] , wherein the acid concentration (calculated as acetic acid) is less than 11 ppm (or, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, or 3 ppm or less), and the acid concentration (calculated as acetic acid) after a 90 wt% aqueous solution is kept at 100°C for one week is less than 23 ppm (or, 20 ppm or less, 19 ppm or less, 18 ppm or less, 17 ppm or less, 16 ppm or less, 15 ppm or less, 14 ppm or less, 13 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, or 2 ppm or less).

[0339]

[13] The 1,3-butanediol product according to any one of [1] to

[12] , wherein the APHA is 6 or less (or 5 or less, 4 or less, 3 or less, or 2 or less), and the APHA after being kept at 180°C in an air atmosphere for 3 hours is 78 or less (or 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 18 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, or 7 or less).

[0340]

[14] The 1,3-butanediol product according to any one of [1] to

[13] , wherein the APHA after being kept at 100°C in an air atmosphere for 75 days is 42 or less (or 35 or less, 30 or less, 25 or less, 20 or less, 18 or less, 16 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less).

[0341]

[15] The 1,3-butanediol product according to any one of [1] to

[14] , wherein the initial boiling point is higher than 203°C (or, higher than 204°C, higher than 205°C, higher than 206°C, higher than 207°C, or higher than 208°C), and / or the dry point is lower than 209°C.

[0342]

[16] The 1,3-butanediol product according to any one of [1] to

[15] , wherein the potassium permanganate test value is 30 minutes or more (or more than 30 minutes, 32 minutes or more, 35 minutes or more, 40 minutes or more, 50 minutes or more, or 60 minutes or more).

[0343]

[17] The 1,3-butanediol product according to any one of [1] to

[16] , wherein the area ratio of the 1,3-butanediol peak (GC area ratio) in gas chromatography analysis (GC analysis) under the following conditions is higher than 98.7% (or, 98.8% or more, 98.9% or more, 99% or more, 99.1% or more, 99.2% or more, 99.3% or more, 99.4% or more, 99.5% or more, 99.6% or more, 99.7% or more, or 99.8% or more).

[0344] (Gas chromatography analysis conditions)

[0345] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0346] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0347] Sample introduction temperature: 250°C.

[0348] Carrier gas: Helium.

[0349] Column gas flow rate: 1 mL / min.

[0350] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0351]

[18] The 1,3-butanediol product according to any one of [1] to

[17] , wherein, in gas chromatography analysis (GC analysis) under the conditions, the total area ratio of peaks having a shorter retention time than the 1,3-butanediol peak is less than 0.3% (or, 0.28% or less, 0.25% or less, 0.23% or less, 0.2% or less, 0.17% or less, 0.15% or less, 0.12% or less, 0.1% or less, 0.07% or less, 0.04% or less, 0.03% or less, 0.02% or less, 0.01% or less, 0.007% or less, 0.005% or less, or 0.002% or less).

[0352]

[19] The 1,3-butanediol product according to any one of [1] to

[18] , wherein, in the gas chromatography analysis (GC analysis) under the conditions, the total area ratio of peaks that are retained for a longer time than the peak of 1,3-butanediol is less than 1.2% (or, less than 1%, less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1%).

[0353]

[20] The 1,3-butanediol product according to any one of [1] to

[19] , wherein the water content is less than 0.4 wt% (or, 0.3 wt% or less, 0.2 wt% or less, 0.1 wt% or less, 0.07 wt% or less, 0.05 wt% or less, 0.03 wt% or less, 0.02 wt% or less, 0.01 wt% or less, or 0.005 wt% or less).

[0354]

[21] A moisturizing agent comprising the 1,3-butanediol product described in any one of [1] to

[20] .

[0355]

[22] The moisturizing agent according to

[21] , wherein the content of the 1,3-butanediol product described in any one of [1] to

[20] is 10% by weight or more (or 30% by weight or more, 50% by weight or more, 80% by weight or more, or 90% by weight or more).

[0356]

[23] A cosmetic comprising the moisturizing agent described in

[21] or

[22] .

[0357]

[24] The cosmetic according to

[23] , wherein the content of the 1,3-butanediol product described in any one of [1] to

[20] is 0.01 to 40 weight % (or 0.1 to 30 weight %, 0.2 to 20 weight %, 0.5 to 15 weight %, or 1 to 10 weight %).

[0358]

[25] The cosmetic according to

[23] or

[24] , wherein the cosmetic is a skin cosmetic, a hair cosmetic, a sunscreen cosmetic, or a makeup cosmetic.

[0359]

[26] A method for producing 1,3-butanediol, wherein purified 1,3-butanediol is obtained from a crude reaction solution containing 1,3-butanediol, the method comprising: a dehydration step for removing water by distillation; a high boiling point removal step for removing high boiling point components by distillation; and a product distillation step for obtaining purified 1,3-butanediol, wherein in a product column used in the product distillation step, the following 1,3-butanediol charge liquid is subjected to a reflux ratio of 0.3 or more (or 0.4 or more, 0.5 or more, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 20 or more, 50 or more, 400 or more, or 500 or more), the acetaldehyde content of the 1,3-butanediol charge liquid is 500 ppm or less (or, 205 ppm or less, 200 ppm or less, 150 ppm or less, 120 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, or less than 2 ppm), crotonaldehyde The content of is 200 ppm or less (or, 150 ppm or less, 130 ppm or less, 110 ppm or less, 100 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or less than 1 ppm), and the content of water is 0.7 wt % or less (or, 0.6 wt % or less, 0.5 wt % or less, 0.4 wt % or less, 0.3 wt % or less, 0.2 wt % or less, or less than 1 ppm). 0.1 wt % or less), and a 1,3-butanediol concentration as determined by gas chromatography under the following conditions is 97.6 area % or more (or, 97.8 area % or more, 98 area % or more, 98.2 area % or more, 98.4 area % or more, 98.6 area % or more, 98.8 area % or more, 99 area % or more, 99.1 area % or more, 99.2 area % or more, 99.3 area % or more, 99.4 area % or more, 99.5 area % or more, 99.6 area % or more, 99.7 area % or more, 99.8 area % or more, or 99.9 area % or more).

[0360] (Gas chromatography analysis conditions)

[0361] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0362] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0363] Sample introduction temperature: 250°C.

[0364] Carrier gas: Helium.

[0365] Column gas flow rate: 1 mL / min.

[0366] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0367]

[27] The method for producing 1,3-butanediol according to

[26] , wherein the distillation rate in the product column is less than 30 weight % (or, 29 weight % or less, 28 weight % or less, 27 weight % or less, 26 weight % or less, 25 weight % or less, 24 weight % or less, 23 weight % or less, 22 weight % or less, 21 weight % or less, 20 weight % or less, 19 weight % or less, 18 weight % or less, 17 weight % or less, 16 weight % or less, 15 weight % or less, 12 weight % or less, 10 weight % or less, 8 weight % or less, 5 weight % or less, 3 weight % or less, 2 weight % or less, 1 weight % or less, 0.8 weight % or less, 0.6 weight % or less, or 0.4 weight % or less).

[0368]

[28] The method for producing 1,3-butanediol according to

[26] or

[27] , wherein at least a portion of the distillate from the product column is reused in a process prior to the product distillation process (e.g., a dehydration process, a dealcoholization process, a low boiling point removal process, or a process prior to these processes).

[0369]

[29] The method for producing 1,3-butanediol according to

[28] , wherein the amount of the distillate of the product column recycled in the process before the product distillation process is 0.01 weight % or more (or, 0.05 weight % or more, 0.1 weight % or more, 0.5 weight % or more, 1 weight % or more, 1.5 weight % or more, 2 weight % or more, 3 weight % or more, 4 weight % or more, 5 weight % or more, 7 weight % or more, 10 weight % or more, or 20 weight % or more) relative to the charge amount in the product column, and is less than 30 weight %.

[0370]

[30] The method for producing 1,3-butanediol according to any one of

[26] to

[29] , wherein the recovery rate of 1,3-butanediol in the product column exceeds 80% (or, 85% or more, 90% or more, 95% or more, or 99% or more).

[0371]

[31] The method for producing 1,3-butanediol according to any one of

[26] to

[30] , wherein in the high boiling point removal tower used in the high boiling point removal step, the following charge liquid containing 1,3-butanediol is subjected to a reflux ratio of 0.03 or more (or, 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.2 or more, 1.5 or more, 2 or more, 3 or more, 4 or more, The distillation is carried out under the conditions of 5 or more, 10 or more, or 20 or more), the acetaldehyde content of the charge liquid containing 1,3-butanediol is 500 ppm or less (or, 205 ppm or less, 200 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, less than 2 ppm, or less than 1 ppm), the crotonaldehyde content is 200 ppm or less (or, 110 ppm or less, 100 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or less than 1 ppm), and the water content is 3 weight % or less (or, 2 weight % or less, 1.2 weight % or less, 1.1 weight % or less, 1.0 weight % or less). % or less, 0.95 wt % or less, 0.9 wt % or less, 0.8 wt % or less, 0.7 wt % or less, 0.6 wt % or less, 0.5 wt % or less, 0.4 wt % or less, 0.3 wt % or less, 0.2 wt % or less, or 0.1 wt % or less), and a 1,3-butanediol concentration obtained by gas chromatography analysis under the above conditions is 95 area % or more (or, 96 area % or more, 96.7 area % or more, 97 area % or more, 98 area % or more, or 99 area % or more).

[0372]

[32] The method for producing 1,3-butanediol according to any one of

[26] to

[31] , wherein the kettle liquid rate in the high-boiling-acid removal tower used in the high-boiling-acid removal step is less than 30 weight % (or, less than 25 weight %, less than 20 weight %, less than 15 weight %, less than 10 weight %, less than 7 weight %, less than 5 weight %, less than 4 weight %, less than 3 weight %, less than 2 weight %, or less than 1 weight %).

[0373]

[33] The method for producing 1,3-butanediol according to any one of

[26] to

[32] , wherein the bottom liquid rate in the high boiling point removal tower used in the high boiling point removal step is 0.01 weight % or more (or, 0.1 weight % or more, 0.5 weight % or more, 1 weight % or more, 2 weight % or more, 3 weight % or more, 4 weight % or more, 5 weight % or more, 6 weight % or more, 7 weight % or more, 8 weight % or more, 9 weight % or more, 10 weight % or more, 15 weight % or more, or 20 weight % or more).

[0374]

[34] The method for producing 1,3-butanediol according to any one of

[26] to

[33] , wherein the recovery rate of 1,3-butanediol in the high-boiling-water removal tower used in the high-boiling-water removal step exceeds 80% (or, 85% or more, 90% or more, 95% or more, or 99% or more).

[0375]

[35] The method for producing 1,3-butanediol according to any one of

[26] to

[34] , wherein at least a portion of the bottom liquid of the high boiling point removal tower used in the high boiling point removal step is reused in a step before the high boiling point removal step.

[0376]

[36] The method for producing 1,3-butanediol according to any one of

[35] , wherein the amount of the kettle liquid of the high-boiling tower recycled in the process before the high-boiling tower is less than 30 weight % (or, 25 weight %, less than 20 weight %, less than 15 weight %, less than 10 weight %, less than 7 weight %, less than 5 weight %, less than 4 weight %, less than 3 weight %, less than 2 weight %, or less than 1 weight %) relative to the charge amount in the high-boiling tower.

[0377]

[37] The method for producing 1,3-butanediol according to

[35] or

[36] , wherein the amount of the kettle liquid of the high-boiling tower recycled in the process before the high-boiling tower is 0.01 weight % or more (or 0.1 weight % or more, 2 weight % or more, 3 weight % or more, 4 weight % or more, 5 weight % or more, 7 weight % or more, 10 weight % or more, or 20 weight % or more) relative to the amount of material loaded in the high-boiling tower.

[0378]

[38] A method for producing 1,3-butanediol, wherein purified 1,3-butanediol is obtained from a crude reaction solution containing 1,3-butanediol, the method comprising: a dehydration step of removing water by distillation; and a high-boiling point removal step of removing high-boiling point components by distillation, wherein in a high-boiling point removal tower used in the high-boiling point removal step, the following charge solution containing 1,3-butanediol is subjected to a reflux ratio of 0.03 or more (or 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0 ... The distillation is carried out under the conditions of 0.001 ppm or more, 0.05 ppm or more, 0.06 ppm or more, 0.07 ppm or more, 0.08 ppm or more, 0.09 ppm or more, 1 ppm or more, 1.2 ppm or more, 1.5 ppm or more, 2 ppm or more, 3 ppm or more, 4 ppm or more, 5 ppm or more, 10 ppm or more, or 20 ppm or more), and the acetaldehyde content of the charge liquid containing 1,3-butanediol is 500 ppm or less (or 205 ppm or less, 200 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less). The content of crotonaldehyde is 200 ppm or less (or 110 ppm or less, 100 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or less than 1 ppm), the content of water is 3 wt % or less (or 2 wt % or less, 1.2 wt % or less, 0.4 wt % or less, 0.3 wt % or less, 0.2 wt % or less, 0.1 wt % or less, 0.05 wt % or less, or 0.03 wt %), and the concentration of 1,3-butanediol obtained by gas chromatography analysis under the following conditions is 96.7 area % or more (or 97% or more, 98% or more, or 99% or more).

[0379] (Gas chromatography analysis conditions)

[0380] Analytical column: a column with dimethylpolysiloxane as the stationary phase (film thickness 1.0 μm×length 30 m×inner diameter 0.25 mm).

[0381] Heating conditions: After heating from 80°C to 120°C at 5°C / min, the temperature was then increased to 160°C at 2°C / min and held for 2 minutes. The temperature was then increased to 230°C at 10°C / min and held at 230°C for 18 minutes.

[0382] Sample introduction temperature: 250°C.

[0383] Carrier gas: Helium.

[0384] Column gas flow rate: 1 mL / min.

[0385] Detector and detection temperature: hydrogen flame ionization detector (FID), 280°C.

[0386]

[39] The method for producing 1,3-butanediol according to any one of

[26] to

[38] , wherein in the dehydration tower used in the dehydration step, the following charge liquid containing 1,3-butanediol is subjected to a reflux ratio exceeding 0.3 (or, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, The distillation is carried out under the conditions of 1,3-butanediol (15 or more, 20 or more, 25 or more, 30 or more, or 40 or more), and the acetaldehyde content of the charge liquid containing 1,3-butanediol is 1000 ppm or less (or, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 300 ppm or less, 200 ppm or less, 155 ppm or less, 140 ppm or less, 100 ppm or less, 90 ppm or less, 80 ppm or less, 70 ppm or less, 60 ppm or less, 50 ppm or less, 40 ppm or less). The content of crotonaldehyde is 400ppm or less (or 300ppm or less, 200ppm or less, 100ppm or less, 150ppm or less, 130ppm or less, 117ppm or less, 100ppm or less, 90ppm or less, 80ppm or less, 70ppm or less, 60ppm or less, 50ppm or less, 40ppm or less, 30ppm or less, 20ppm or less, 10ppm or less, 5ppm or less). m or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less), the water content is 90 wt % or less (or, 85 wt % or less, 80 wt % or less, 70 wt % or less, 60 wt % or less, 50 wt % or less, 40 wt % or less, 35 wt % or less, 30 wt % or less, 25 wt % or less, 15 wt % or less, or 10 wt % or less), and the 1,3-butanediol concentration obtained by gas chromatography analysis under the said conditions is 95 area % or more (or, 96 area % or more, 96.7 area % or more, 97 area % or more, 98 area % or more, or 99 area % or more).

[0387]

[40] The method for producing 1,3-butanediol according to any one of

[26] to

[39] , wherein the distillation rate in the dehydration tower used in the dehydration step is 95 weight % or less (or, 90 weight % or less, 85 weight % or less, 80 weight % or less, 75 weight % or less, 70 weight % or less, 65 weight % or less, 60 weight % or less, 55 weight % or less, 50 weight % or less, 45 weight % or less, 40 weight % or less, 35 weight % or less, 30 weight % or less, 25 weight % or less, 20 weight % or less, 15 weight % or less, 10 weight % or less, or 5 weight % or less).

[0388]

[41] The method for producing 1,3-butanediol according to any one of

[26] to

[40] , wherein the recovery rate of 1,3-butanediol in the dehydration tower used in the dehydration step is 99.3% or more.

[0389]

[42] The method for producing 1,3-butanediol according to any one of

[26] to

[41] , wherein the crude reaction liquid containing 1,3-butanediol is a crude reaction liquid obtained by hydrogen reduction of butanediol.

[0390]

[43] The method for producing 1,3-butanediol according to any one of

[26] to

[42] , wherein the method for producing 1,3-butanediol further comprises at least one process selected from the following processes: an alkali treatment process, in which a process material stream containing 1,3-butanediol is treated with an alkali; a desalting process, in which salt is removed from the process material stream containing 1,3-butanediol; and a dealcoholization process, in which low-boiling substances containing alcohol are removed from the process material stream containing 1,3-butanediol.

[0391] Industrial applicability

[0392] The 1,3-butanediol products disclosed herein are highly pure, colorless, and odorless (or nearly colorless and odorless). They are less susceptible to coloration and odor generation over time, and / or are less susceptible to an increase in acid concentration over time, even in a water-containing state. These 1,3-butanediol products can be used as raw materials for moisturizers and cosmetics that exhibit excellent moisturizing properties and maintain high quality over a long period of time.

[0393] Description of Reference Numerals

[0394] A: Dehydration tower

[0395] B: Desalination tower

[0396] C: High boiling point removal distillation tower (high boiling point removal tower)

[0397] D: Alkali Reactor

[0398] E: Dealkalization Tower

[0399] F: Product distillation tower (product tower)

[0400] A-1, B-1, C-1, E-1, F-1: Condensers

[0401] A-2, C-2, F-2: Reboiler

[0402] X-1: Crude 1,3-butanediol

[0403] X-2: Water (wastewater)

[0404] X-3: salt, high boiling point substances and part of 1,3-butanediol

[0405] X-4: high boiling point substances and part of 1,3-butanediol

[0406] X-5: caustic soda, high boiling point substances and part of 1,3-butanediol

[0407] X-6: low boiling point substances and part of 1,3-butanediol

[0408] Y: 1,3-Butanediol products

Claims

1. A 1,3-butanediol product, wherein The 1,3-butanediol product contains at least one of methyl vinyl ketone, acetone, butyraldehyde, butyral, a compound represented by the following formula (1), a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula (4), and a compound represented by the following formula (5), and at least one of the eight contents is less than 8 ppm.

2. The 1,3-butanediol product according to claim 1, wherein The sum of the content of methyl vinyl ketone, the content of acetone, the content of butyraldehyde, the content of butyral, the content of the compound represented by formula (1), the content of the compound represented by formula (2), the content of the compound represented by formula (3), the content of the compound represented by formula (4) and the content of the compound represented by formula (5) is less than 71 ppm.

3. The 1,3-butanediol product according to claim 1 or 2, wherein At least the aldol content is less than 8 ppm.

4. The 1,3-butanediol product according to claim 1 or 2, wherein At least the content of the compound represented by formula (3) is less than 8 ppm.

5. The 1,3-butanediol product according to claim 1 or 2, wherein The total content of methyl vinyl ketone, acetone and butyraldehyde was 24 ppm or less.

6. The 1,3-butanediol product according to claim 1 or 2, wherein The total content of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (4), and the compound represented by formula (5) is 24 ppm or less.

7. The 1,3-butanediol product according to claim 1 or 2, wherein The acetaldehyde content is less than 4ppm, and the crotonaldehyde content is less than 2ppm.

8. The 1,3-butanediol product according to claim 1 or 2, wherein The acid concentration was less than 11 ppm in terms of acetic acid, and the acid concentration after a 90 wt % aqueous solution was kept at 100° C. for one week was less than 23 ppm in terms of acetic acid.

9. The 1,3-butanediol product according to claim 1 or 2, wherein The APHA is 6 or less, and the APHA after being kept at 180° C. for 3 hours in an air atmosphere is 78 or less.

10. The 1,3-butanediol product according to claim 1 or 2, wherein The initial boiling point is higher than 203°C and / or the dry point is lower than 209°C.

11. The 1,3-butanediol product according to claim 1 or 2, wherein The potassium permanganate test value is more than 30 minutes.

12. A moisturizing agent comprising the 1,3-butanediol product according to claim 1 or 2.

13. A cosmetic comprising the moisturizing agent according to claim 12.

Images