1,3-butanediol product and use thereof

Abstract

Provided are a 1,3-butanediol product and use thereof. The 1,3-butanediol product has an improved odor and lower skin irritation, and after long-term storage, the crotonaldehyde content thereof remains at a relatively low level. In gas chromatography analysis of the 1,3-butanediol product, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the area ratios of peaks appearing within the relative retention time range of 1.32 to 1.38 is greater than 0 and less than or equal to 750 ppm.

Description

A 1,3-butanediol product and its application Technical Field

[0001] This invention relates to a 1,3-butanediol product and its application. Background Technology

[0002] 1,3-Butanediol is a colorless and odorless liquid with good moisturizing properties and low skin irritation. It is widely used in cosmetics as a moisturizer and solvent.

[0003] There are various processes and methods for manufacturing 1,3-butanediol. (1) British Patent GB853266A discloses a method for generating 1,3-butanediol by aldol condensation in an alkaline solution using acetaldehyde as a raw material, followed by hydrogen reduction of 3-hydroxybutane to produce 1,3-butanediol. (2) Chinese Patent CN103102229B9 discloses a method for preparing 1,3-butanediol by Prins reaction using formaldehyde and propylene as raw materials under the action of an acidic oxide catalyst. (3) Japanese Patent JP3290 466B2 discloses a three-step process for preparing 1,3-butanediol, which includes condensing acetaldehyde hydroxyl to generate 2,6-dimethyl-1,3-dioxane-4-ol, then decomposing 2,6-dimethyl-1,3-dioxane-4-ol to obtain dimeric paraldol, followed by hydrogenation to obtain 1,3-butanediol; (4) Canadian patent CA2759994C discloses a method for synthesizing 1,3-butanediol using non-naturally occurring microorganisms. Other methods include: (5) laser irradiation of ethanol containing hydrogen peroxide and saturated with nitrogen to directly synthesize 1,3-butanediol; (6) reaction of acrolein with 2,2-dimethyl-1,3-propanediol, followed by carbonyl synthesis, hydrolysis, and hydrogenation to obtain 1,3-butanediol.

[0004] Considering factors such as economy and product quality, most currently use (1) acetaldehyde condensation and hydrogenation method to prepare it, the specific process is as follows:

[0005] 1) Acetaldehyde condensation: In alkaline solution, acetaldehyde condenses to produce 3-hydroxybutyraldehyde;

[0006] 2) Hydrogenation process: 3-hydroxybutyraldehyde is hydrogenated to produce 1,3-butanediol;

[0007] 3) Separation and purification: Impurities are removed through processes such as extraction and distillation;

[0008] Chinese patent application CN110790634A discloses a method for producing 1,3-butanediol with a purity greater than 99.5% by using segmented hydrogenation and adding modifiers to the hydrogenation catalyst, thereby reducing the content of odor-causing impurity 1,3-dioxane to below 0.01 wt%. Chinese patent application CN117940397A uses a heating method to remove the odor-causing substance methyl vinyl ketone. Chinese patent application CN117940396A employs Pd / C catalytic hydrogenation to reduce the odor-causing substance 6-hydroxy-2-hexanone.

[0009] The presence or absence of odor is an important indicator for the application of 1,3-butanediol in cosmetics. However, even more important is that cosmetics come into contact with the skin and may even be used in oral hygiene, tableware cleaning, etc., potentially entering the human digestive system. Therefore, safety is also a more crucial indicator for cosmetic applications. Although the aforementioned patent controls impurities that produce odor, it does not consider the impact of residual impurities on human safety. Currently used methods for producing 1,3-butanediol, whether it is the acetaldehyde condensation method, the propylene carbonylation method, or the 2,6-dimethyl-1,3-dioxane-4-ol decomposition method, all produce the intermediate product 3-hydroxybutyraldehyde, along with a small amount of crotonaldehyde. 3-hydroxybutyraldehyde is easily dehydrated to produce crotonaldehyde. Crotonaldehyde has an LC50 of 240 mg / kg (oral in mice), and is irritating to the human eye at concentrations above 45 ppm. China's "Cosmetic Technical Specifications-2015" lists it as a prohibited substance.

[0010] Chinese patent application CN114340586A provides a 1,3-butanediol product that specifies the acetal of 3-hydroxybutanal and 1,3-butanediol. The provided 1,3-butanediol product is colorless and transparent with minimal color change over time. Summary of the Invention

[0011] This invention provides a 1,3-butanediol product and its application. The 1,3-butanediol product provided by this invention has an improved odor and lower skin irritation, and its crotonaldehyde content can still be maintained at a low level after a long period of storage.

[0012] To achieve its objective, the present invention provides the following technical solution:

[0013] In one aspect, the present invention provides a 1,3-butanediol product, wherein, in gas chromatography analysis, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the peak area ratios appearing in the range of 1.32-1.38 relative retention time is >0 and ≤750ppm.

[0014] The analytical conditions for the gas chromatography method are as follows:

[0015] Gas chromatograph: Agilent 7890 gas chromatograph;

[0016] Detector: Flame Ionization Detector (FID);

[0017] Chromatographic column: HP-VOC column, column length 60m × inner diameter 0.32mm × film thickness 1.8μm;

[0018] Carrier gas: nitrogen, flow rate 1.5 ml / min;

[0019] Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min;

[0020] Vaporization chamber temperature: 260℃;

[0021] Detector temperature: 280℃.

[0022] Preferably, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention time is 5-700 ppm, for example 10-700 ppm.

[0023] Furthermore, after adjusting the pH of a 50wt% aqueous solution of the 1,3-butanediol product to 6 and storing it at 50°C for 90 days, the crotonaldehyde content does not exceed 10ppm.

[0024] Another aspect of the present invention provides a humectant comprising the 1,3-butanediol product described above.

[0025] Another aspect of the present invention provides a cosmetic product comprising the moisturizer described above.

[0026] In another aspect, the present invention provides a method for improving the odor and / or skin irritation of a composition containing a 1,3-butanediol article, wherein the added 1,3-butanediol article needs to meet the following requirements to improve the odor and / or skin irritation of the composition:

[0027] In the gas chromatography analysis of the 1,3-butanediol product, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0,

[0028] The sum of the area fractions of peaks appearing in the range of relative retention time of 1.32-1.38 is >0 and ≤750ppm;

[0029] The analytical conditions for the gas chromatography method are as follows:

[0030] Gas chromatograph: Agilent 7890 gas chromatograph;

[0031] Detector: Flame Ionization Detector (FID);

[0032] Chromatographic column: HP-VOC column, column length 60m × inner diameter 0.32mm × film thickness 1.8μm;

[0033] Carrier gas: nitrogen, flow rate 1.5 ml / min;

[0034] Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min;

[0035] Vaporization chamber temperature: 260℃;

[0036] Detector temperature: 280℃.

[0037] Preferably, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention time is 5-700 ppm, for example 10-700 ppm.

[0038] The present invention also provides a method for preparing the 1,3-butanediol product described above, comprising the following steps:

[0039] S1. Using a feed solution containing 3-hydroxybutyraldehyde as a hydrogenation feed solution, a hydrogenation reaction is carried out to obtain a reaction solution containing 1,3-butanediol.

[0040] S2. The reaction solution containing 1,3-butanediol is separated and purified to obtain 1,3-butanediol product;

[0041] In step S1, before the hydrogenation reaction is carried out, the acid value of the hydrogenation feed solution is controlled to be 5-200 ppm;

[0042] Preferably, in the 3-hydroxybutyraldehyde-containing solution, the content of 3-hydroxybutyraldehyde is >20wt%, more preferably >55wt%;

[0043] Preferably, the water content in the 3-hydroxybutyraldehyde-containing solution is 1-42 wt%, more preferably 5-42 wt%.

[0044] The technical solution provided by this invention has the following beneficial effects:

[0045] 1,3-Butanediol products that meet the specific peak area ratio requirements of this invention have significantly improved odor and significantly reduced skin irritation, and do not show a significant increase in crotonaldehyde content during long-term storage, but can still maintain a low content level. Detailed Implementation

[0046] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0048] This invention provides a 1,3-butanediol product, wherein, in gas chromatography analysis, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the peak area ratios appearing in the range of 1.32-1.38 relative retention time is >0 and ≤750ppm.

[0049] The analytical conditions for the gas chromatography method are as follows:

[0050] Gas chromatograph: Agilent 7890 gas chromatograph;

[0051] Detector: Flame Ionization Detector (FID);

[0052] Chromatographic column: HP-VOC column, column length 60m × inner diameter 0.32mm × film thickness 1.8μm;

[0053] Carrier gas: nitrogen, flow rate 1.5 ml / min;

[0054] Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min;

[0055] Vaporization chamber temperature: 260℃;

[0056] Detector temperature: 280℃.

[0057] In some examples, when the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0 in gas chromatography analysis, the sum of the peak area fractions appearing in the range of relative retention time 1.32-1-38 is 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 750 ppm, etc. More preferably, when the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0, the sum of the peak area fractions appearing in the range of relative retention time 1.32-1.38 is 5-700 ppm, for example, 10-700 ppm.

[0058] Specifically, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the molecular weight of the substance with a relative retention time in the range of 1.32-1.35 is 188, and it is an acetal formed by 3-hydroxybutyraldehyde and a saturated six-carbon diol, having the following structural formula (I) or (II):

[0059] Specifically, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the molecular weight of the substance with a relative retention time in the range of 1.35-1.38 is 186, and it is an acetal formed by 3-hydroxybutyraldehyde and an unsaturated six-carbon diol, having the following structural formula (III) or (IV):

[0060] In the production of 1,3-butanediol, particularly through the acetaldehyde condensation and hydrogenation process, acetaldehyde and 3-hydroxybutyraldehyde are typically produced. This process involves acetaldehyde, 3-hydroxybutyraldehyde, and byproducts such as formaldehyde, acetone, butyraldehyde, crotonaldehyde, methyl vinyl ketone, 6-hydroxy-2-hexanone, and methyl hydroxyethyl ketone, all containing carbonyl groups. These substances negatively impact the product's odor, color, and skin irritation. Subsequent hydrogenation and separation processes reduce their concentrations. For example, the boiling points of crotonaldehyde and 3-hydroxybutyraldehyde differ significantly from those of 1,3-butanediol, making them easily separated through distillation. Furthermore, butyraldehyde and acetaldehyde, as well as crotonaldehyde and acetaldehyde, react to produce 1,3-dihydroxy diols. These diols readily react with the aforementioned carbonyl-containing compounds to produce acetals and ketals containing a 1,3-dioxane structure, such as those with structural formulas (I)-(IV). The inventors have discovered that these substances are difficult to separate and remove in subsequent processes by means of hydrogenation or distillation, and are contained in 1,3-butanediol. In downstream applications, they are introduced into cosmetics along with the use of 1,3-butanediol. Moreover, these substances are unstable, especially under acidic conditions, and are prone to decomposition to produce aldehydes and ketones, which affect the odor, color, and skin irritation of 1,3-butanediol products. The inventors discovered that, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0 according to the analytical conditions of the gas chromatography method described above, the sum of the peak area ratios appearing in the range of 1.32-1.35 and the peak area ratios appearing in the range of 1.35-1.38 is greater than 0 and does not exceed 750 ppm. That is, the sum of the peak area ratios appearing in the range of 1.32-1.38 is greater than 0 and does not exceed 750 ppm, for example, 5-750 ppm, 5-700 ppm, 10-750 ppm, 10-700 ppm, for example, <500 ppm, preferably <50 ppm. Such 1,3-butanediol products have significantly improved odor and significantly reduced skin irritation compared to products with higher peak area ratios in the above-mentioned relative retention time range. Specifically, the improved odor is manifested in a significant reduction or weakening of the pungent odor.

[0061] The 1,3-butanediol product provided by this invention does not show a significant increase in crotonaldehyde content during prolonged storage, maintaining a low content level. Specifically, a 50wt% aqueous solution of the 1,3-butanediol product provided by this invention, after adjusting the pH to 6 and storing at 50°C for 90 days, has a crotonaldehyde content of no more than 10 ppm, more preferably no more than 1 ppm.

[0062] In the text, "peak area ratio" refers to the proportion of the area of ​​a specific peak in the total area of ​​all peaks.

[0063] Among them, "specific peak area" refers to the integral area of ​​the peak corresponding to a certain relative retention time in gas chromatography testing; "total peak area" refers to the sum of the integral areas of all peaks in gas chromatography testing.

[0064] In the 1,3-butanediol product of the present invention, under the analytical conditions of the above-mentioned gas chromatography, the peak area ratio of 1,3-butanediol is preferably greater than 99.5%, more preferably greater than 99.7%, and even more preferably greater than 99.8%.

[0065] The 1,3-butanediol products provided by this invention are particularly suitable for use in moisturizers and cosmetics, and have significant improvements in terms of odor and skin irritation.

[0066] The present invention also provides a humectant comprising the 1,3-butanediol product described above.

[0067] The present invention also provides a cosmetic product comprising the moisturizer described above.

[0068] The present invention also provides a method for improving the odor and / or skin irritation of a composition containing a 1,3-butanediol product, wherein the added 1,3-butanediol product must meet the following requirements to improve the odor and / or skin irritation of the composition:

[0069] In the gas chromatography analysis of the 1,3-butanediol product, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the peak area ratios appearing in the range of relative retention time of 1.32-1.38 is >0 and ≤750ppm.

[0070] The analytical conditions for the gas chromatography method are as follows:

[0071] Gas chromatograph: Agilent 7890 gas chromatograph;

[0072] Detector: Flame Ionization Detector (FID);

[0073] Chromatographic column: HP-VOC column ((6% cyanopropyl-phenyl)-methylpolysiloxane column), column length 60m × inner diameter 0.32mm × film thickness 1.8μm;

[0074] Carrier gas: nitrogen, flow rate 1.5 ml / min;

[0075] Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min;

[0076] Vaporization chamber temperature: 260℃;

[0077] Detector temperature: 280℃.

[0078] Furthermore, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention time is 5-700 ppm, for example 10-700 ppm.

[0079] The present invention also provides a method for preparing the 1,3-butanediol product described above, comprising the following steps:

[0080] S1. Using a feed solution containing 3-hydroxybutyraldehyde as a hydrogenation feed solution, a hydrogenation reaction is carried out to obtain a reaction solution containing 1,3-butanediol.

[0081] S2. The reaction solution containing 1,3-butanediol is separated and purified to obtain 1,3-butanediol product;

[0082] In step S1, before the hydrogenation reaction is carried out, the acid value of the hydrogenation feed solution is controlled to be 5-200 ppm.

[0083] The preparation of 1,3-butanediol by hydrogenation of 3-hydroxybutyraldehyde is well known in the art. The main improvement of the preparation method of the present invention lies in the fact that the inventors have discovered that by controlling the acid value of the hydrogenation feed solution in step S1 to 5-200 ppm, it is beneficial to obtain a 1,3-butanediol product that meets the specific peak area ratio requirements of the present invention. All acid values ​​mentioned above are based on acetic acid content.

[0084] In some examples, the acid value of the hydrogenation feed solution is controlled to be, for example, 5 ppm, 10 ppm, 20 ppm, 30 ppm, 50 ppm, 70 ppm, 90 ppm, 100 ppm, 120 ppm, 150 ppm, 170 ppm, 200 ppm, etc.

[0085] The composition of the hydrogenation feedstock is not particularly limited. It can be an acetaldehyde condensate, a reaction solution obtained by stripping an acetaldehyde condensate (i.e., stripper), a 3-hydroxybutyraldehyde solution, or purified 3-hydroxybutyraldehyde. The stripper obtained by stripping an acetaldehyde condensate or a condensate containing 3-hydroxybutyraldehyde obtained from acetaldehyde condensation mainly comprises 3-hydroxybutyraldehyde, and may also include one or more of 2,6-dimethyl-1,3-dioxane-4-ol (aldoxane) and di-m-polybutyraldehyde, and may further contain condensation byproducts such as crotonaldehyde, butyraldehyde, and acetaldehyde. Preferably, the hydrogenation feedstock is a reaction mixture containing 3-hydroxybutyraldehyde obtained from acetaldehyde condensation. The stripper, obtained by stripping to remove unreacted acetaldehyde, can recover unreacted acetaldehyde through stripping, which helps reduce manufacturing costs.

[0086] In some examples, the steps for preparing 1,3-butanediol products include an acetaldehyde condensation step to obtain a hydrogenation feedstock. In the acetaldehyde condensation step, a reaction mixture containing 3-hydroxybutyraldehyde is prepared by the condensation reaction of acetaldehyde. Preferably, unreacted acetaldehyde is removed from this reaction mixture before it is used as the hydrogenation feedstock. The acetaldehyde condensation step can be carried out in the presence of an alkaline catalyst. The alkaline catalyst can be any appropriate catalyst suitable in the art, and there are no particular limitations. For example, as long as the system can be controlled under alkaline conditions, inorganic bases such as sodium hydroxide or sodium carbonate can be used; organic quaternary ammonium bases can also be used, and further, solid composite catalysts such as MgO-MgAl2O4 solid composite catalysts can also be used. For the condensation reactor, a batch reactor or a fixed-bed reactor can be used. The amount of alkaline catalyst relative to the mass of acetaldehyde can be 0.05-5%, preferably 0.5-2%. In the condensation reaction, the condensation reaction temperature can be 0–30°C, preferably 10–15°C (e.g., 12°C, 13°C, 14°C); the reaction time can be 2–20 h, preferably 3–10 h. The unreacted acetaldehyde can be removed by stripping, such as nitrogen stripping, or short-path evaporation.

[0087] The hydrogenation reaction can be carried out in the presence of a hydrogenation catalyst, and any appropriate catalyst suitable for the art can be selected without particular limitation. For example, a catalyst containing nickel or cobalt, such as Raney nickel, can be selected. There are no particular limitations on the hydrogenation reaction pressure, catalyst dosage, etc., and conventional process conditions in the art can be used. Specifically, for example, the hydrogenation reaction temperature is 80-140°C, more preferably 90-120°C, and even more preferably 100-120°C; the reaction pressure can be 2-20 MPa (gauge pressure); and the catalyst dosage relative to the mass of 3-hydroxybutyraldehyde can be 1-5%.

[0088] The separation and purification steps used in step S2 can be, but are not limited to, dehydration, desalination, extraction, heavy removal, and light removal processes; furthermore, adsorption, stripping, and other processes can be selected.

[0089] In some examples, in step S2, the separation and purification are performed using the following method:

[0090] The reaction liquid obtained from the hydrogenation reaction is separated by distillation. The distillation column has 20-40 plates. First, low-boiling-point compounds such as ethanol and water are removed under a pressure of 5-50 kPa. After removal, the pressure is reduced to 0.5-3 kPa and the product with a purity of ≥99.7% is collected.

[0091] The 1,3-butanediol obtained by distillation is extracted. Specifically, 1,3-butanediol, water, and methyl isobutyl ketone are mixed and shaken, with the weight of water being 1-5 times that of 1,3-butanediol and the weight of methyl isobutyl ketone being 0.2-3 times. The mixture is then allowed to stand, allowing phase separation between the aqueous and organic layers. Methyl isobutyl ketone is further added to the separated aqueous phase, with the added amount being 0.02-1 times the weight of the aqueous phase. The aforementioned shaking, standing, and phase separation operations are repeated once or multiple times. After extraction, the aqueous layer is dehydrated and concentrated to obtain the 1,3-butanediol product.

[0092] In the production process of 1,3-butanediol by acetaldehyde condensation and hydrogenation, acetaldehyde undergoes condensation and hydrogenation to produce 1,3-butanediol, accompanied by many side reactions that generate many undesirable substances. For example, 3-hydroxybutyraldehyde is unstable when heated and easily produces crotonaldehyde. Crotonaldehyde is hydrogenated to produce butyraldehyde. Crotonaldehyde and butyraldehyde condense with residual acetaldehyde to produce a six-carbon hydroxyl, which is further hydrogenated to obtain a six-carbon diol with a 1,3-dihydroxy structure. In addition, many byproducts are generated, such as formaldehyde, acetone, methyl vinyl ketone, methyl hydroxyethyl ketone, 6-hydroxy-2-hexanone, acetic acid, and esters of 1,3-butanediol. These substances are easily removed in subsequent separation processes. Because the six-carbon diol has a 1,3-dihydroxy structure, it easily reacts with aldehydes and ketones to form structurally stable acetals and ketals with a 1,3-dioxane structure, specifically substances with the above structural formulas (I), (II), (III), and / or (IV). The inventors discovered that these acetal and ketal compounds are difficult to completely remove during subsequent separation processes, mainly because they are highly compatible with the main product, 1,3-butanediol, and have similar boiling points, making conventional extraction and separation difficult, resulting in high residues in 1,3-butanediol. When added to cosmetics, they are unstable and easily decompose to produce aldehydes, ketones, and six-carbon diols. These aldehydes and ketones may increase the odor of cosmetics, increase product color, or increase the risk of skin sensitization, acne, or cancer.

[0093] The inventors have discovered that by controlling the acid value in the hydrogenation feedstock solution, the content of the substance with the specific relative retention time mentioned above in this invention in the 1,3-butanediol product can be controlled, thereby improving the odor of the obtained product and / or reducing skin irritation. The acid value in the hydrogenation feedstock solution can be controlled by adjusting the acid value of the feedstock solution with an acidic substance before the hydrogenation reaction, or by adjusting the acid value of the reaction mixture containing 3-hydroxybutyraldehyde obtained from the acetaldehyde condensation reaction. Preferably, the acid value of the reaction mixture containing 3-hydroxybutyraldehyde is adjusted after the acetaldehyde condensation reaction is completed. Since the acetaldehyde condensation reaction uses an alkaline substance as a catalyst, after the reaction is completed, an acidic substance is needed to neutralize the condensation reaction solution and stop the reaction. Adjusting the acid value at this stage can reduce the number of operational steps. Since the condensation reaction solution needs further separation, including but not limited to steps such as stripping acetaldehyde, dehydration, and desalination, it is preferable to control the acid value of the reaction mixture containing 3-hydroxybutyraldehyde at a higher level when adjusting the acid value in this way. Specifically, the acid value should be controlled between 50ppm and 500ppm, preferably between 50ppm and 200ppm, and more preferably between 100ppm and 200ppm. This will ultimately yield a hydrogenation feed solution with an acid value of 5-200ppm. If the acid value of the hydrogenation feed solution is too high, it will lead to catalyst deactivation and hinder the hydrogenation reaction. At the same time, under high acid value conditions, the aldol condensation reaction will continue, and the aldehydes in the hydrogenation feed solution will continue to react, thereby increasing the content of the substances (I), (II), (III), and / or (IV) in the final product.

[0094] There are no particular limitations on the substances used to adjust the acid value; one or more of organic acids and / or inorganic acids can be used. Organic acids include formic acid and acetic acid, while inorganic acids include hydrochloric acid and sulfuric acid. Small molecule organic acids such as formic acid and acetic acid are more preferred. Preferably, inorganic acids can be used when the water content in the system is greater than 20 wt%.

[0095] The content of 3-hydroxybutyraldehyde in the hydrogenation feed solution is not particularly limited. Considering the front-end condensation process and subsequent separation, the content of 3-hydroxybutyraldehyde is preferably greater than 20 wt%, such as 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt%, etc., or it can be greater than 55 wt%. In a preferred embodiment, the hydrogenation feed solution preferably contains 1-42 wt% water, such as 1 wt%, 2 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 35 wt%, 40 wt%, 42 wt%, etc., more preferably 5-42 wt% water, such as 10-20 wt% water.

[0096] The present invention will be further illustrated by the following embodiments, but it should not be construed as the present invention being limited to these embodiments.

[0097] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0098] The detection methods in the following examples and comparative examples are described below:

[0099] The conditions for gas chromatography analysis of 1,3-butanediol products are as follows:

[0100] Gas chromatograph: Agilent 7890 gas chromatograph;

[0101] Detector: Flame Ionization Detector (FID);

[0102] Chromatographic column: Agilent HP-VOC column ((6% cyanopropyl-phenyl)-methylpolysiloxane column), column length 60m × inner diameter 0.32mm × film thickness 1.8μm;

[0103] Carrier gas: nitrogen, flow rate 1.5 ml / min;

[0104] Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min;

[0105] Vaporization chamber temperature: 260℃;

[0106] Detector temperature: 280℃.

[0107] In gas chromatography analysis, the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0. The area ratio of peaks with relative retention times in the range of 1.32-1.35 and the area ratio of peaks with relative retention times in the range of 1.35-1.38 are calculated.

[0108] Methods for testing crotonaldehyde content in 1,3-butanediol products obtained in each embodiment and comparative example after storage:

[0109] (1) Prepare a 50 wt% aqueous solution of 1,3-butanediol sample, adjust the pH to 6 with hydrochloric acid, and place it in a 50℃ oven for 90 days to be used as the sample to be tested.

[0110] (2) The crotonaldehyde content was determined using the following HPLC method.

[0111] a) Weigh 0.20 g of 2,4-dinitrophenylhydrazine and place it in an Erlenmeyer flask. Add 40 ml of concentrated hydrochloric acid (36.5 wt%) to dissolve it, then add 60 ml of deionized water and shake well to obtain a 2,4-dinitrophenylhydrazine hydrochloric acid solution for later use.

[0112] b) Weigh 0.2g of the sample to be tested, place it in a stoppered test tube, add acetonitrile to 2ml, add 0.4ml of 2,4-dinitrophenylhydrazine hydrochloric acid solution, and then add 10wt% sodium hydroxide aqueous solution to adjust to neutral. Mix well to obtain the test solution.

[0113] c) Prepare crotonaldehyde aqueous solution and measure it using the standard curve method. The standard curve concentrations are 0.5 mg / kg, 1 mg / kg, 3 mg / kg, 5 mg / kg, 7 mg / kg, and 9 mg / kg.

[0114] d) HPLC chromatographic conditions;

[0115] Chromatographic column: C18 column (250mm×4.6mm×5μm, or equivalent column);

[0116] Mobile phase: methanol + water (volume ratio of methanol to water is 60:40);

[0117] Flow rate: 1.0 mL / min;

[0118] Detection wavelength: 355nm;

[0119] Column temperature: 25℃;

[0120] Injection volume: 10 μL.

[0121] Product application performance testing:

[0122] Odor testing method: Prepare a 50 wt% aqueous solution of 1,3-butanediol. Select 10 trained personnel to evaluate the odor, and score them according to the following evaluation criteria. The average score is taken as the final result. The evaluation criteria are as follows:

[0123] 5: Odorless

[0124] 4: Slight odor

[0125] 3: An odor is acceptable.

[0126] 2: Unacceptable odor

[0127] 1: A distinctly pungent odor

[0128] Skin irritation (patch) test method:

[0129] 1) Prepare a 50 wt% aqueous solution of 1,3-butanediol sample, adjust the pH to 6 with hydrochloric acid, and place it in a 50℃ oven for 90 days to obtain the sample to be tested.

[0130] 2) Place 0.025 ml of the sample to be tested into a spot applicator, and apply it topically to the flexor side of the subject's forearm with hypoallergenic adhesive tape. Remove the tape after 24 hours, and observe the skin reaction 24 hours after removal. Record the results according to the skin reaction grading standard. A total of 30 subjects participated in the scoring. The skin reaction grading standard is as follows:

[0131] The test results are recorded as n, where n represents the number of people who rated the corresponding rating level.

[0132] Example 1

[0133] Preparation of hydrogenation feedstock solution: 100g of 0.5wt% sodium hydroxide aqueous solution was added dropwise to 500g of acetaldehyde over a period of 4 hours. The condensation reaction temperature was controlled at 10-15℃ using a cold bath. After the addition was complete, the reaction continued for 3 hours. Acetic acid was then added to the system to adjust the acid value to 50ppm. Unreacted acetaldehyde was recovered by short-path evaporation to obtain the hydrogenation feedstock solution (i.e., a condensation solution containing 3-hydroxybutyraldehyde). The obtained hydrogenation feedstock solution mainly contained 85.2wt% 3-hydroxybutyraldehyde, had a water content of 12.5wt%, and an acid value of 5ppm.

[0134] Hydrogenation reaction: Take 300g of the above hydrogenation feed solution, add 8.5g of Raney nickel catalyst (Raney 6800, purchased from GRACE), hydrogenation temperature is 80℃, reaction pressure is 9Mpa (gauge pressure), and reaction time is 3 hours; after the reaction is completed, a reaction solution containing 1,3-butanediol is obtained.

[0135] Refining process:

[0136] The reaction solution containing 1,3-butanediol was subjected to distillation separation using a 30-plate distillation column. First, the distillation separation was carried out at a pressure of 20 kPa to separate low-boiling-point compounds such as ethanol and water. Then, the pressure was reduced to 2.0 kPa, and 1,3-butanediol with a purity of ≥99.7% was collected.

[0137] Then, extraction was performed. 100g of 1,3-butanediol, 100g of water, and 60g of methyl isobutyl ketone obtained from distillation were added to a separatory funnel. After shaking for 2-3 minutes, the mixture was allowed to stand for 5 minutes to allow phase separation between the aqueous and organic layers. 6g of methyl isobutyl ketone was further added to the separated aqueous layer (approximately 180g), and after shaking for 2-3 minutes, the mixture was allowed to stand for 5 minutes to separate the aqueous and organic layers. This process was repeated twice with the aqueous layer.

[0138] The extracted aqueous layer was added to a three-necked flask and concentrated by dehydration at an oil bath temperature of 150°C and 8 kPa for 30 minutes to obtain the 1,3-butanediol product.

[0139] Example 2

[0140] The same process as in Example 1 will not be repeated here. The differences are explained below:

[0141] When preparing the hydrogenation feedstock solution, the amount of sodium hydroxide added was adjusted, and 50g of a 0.5wt% sodium hydroxide aqueous solution was added dropwise over a period of 4 hours. The final hydrogenation feedstock solution mainly contained 91.4wt% 3-hydroxybutyraldehyde, 5.2wt% water, and 58ppm acid value.

[0142] The hydrogenation reaction was carried out as in Example 1, except that the hydrogenation temperature was 120°C and the reaction pressure was 12 MPa.

[0143] The refining process is the same as in Example 1.

[0144] Example 3

[0145] Preparation of hydrogenation feedstock: 325g of 3-hydroxybutyral dimethyl acetal was added to 75g of 5wt% hydrochloric acid solution and 200g of water. The mixture was reacted at 20-30℃ for 5 hours, and methanol was removed by short-path evaporation. The resulting hydrogenation feedstock mainly contained 65.3wt% 3-hydroxybutyral and 30wt% water; the acid value was 102ppm.

[0146] The obtained hydrogenated feedstock solution was then subjected to a hydrogenation reaction and purification. The hydrogenation reaction was carried out in accordance with Example 1, except that the hydrogenation temperature was 140°C. The purification process was the same as in Example 1.

[0147] Example 4

[0148] The same process as in Example 1 will not be repeated here. The differences are explained below:

[0149] When preparing the hydrogenation feedstock solution, 50g of sodium hydroxide aqueous solution with a mass concentration of 0.5wt% was added dropwise to 800g of 60wt% acetaldehyde aqueous solution for 4h. The final hydrogenation feedstock solution mainly contained 58wt% 3-hydroxybutyraldehyde, 40.6wt% water, and 196ppm acid value.

[0150] The hydrogenation reaction was carried out as in Example 1, except that the hydrogenation temperature was 110°C.

[0151] The refining process is the same as in Example 1.

[0152] Comparative Example 1

[0153] Preparation of hydrogenation feedstock: 100g of 0.5wt% sodium hydroxide aqueous solution was added dropwise to 500g of acetaldehyde over 4 hours. The condensation reaction temperature was controlled at 10-15℃ using a cold bath. After the addition was complete, the reaction continued for 3 hours. Acetic acid was then added to the system to adjust the acid value to 32ppm. Unreacted acetaldehyde was recovered by short-path evaporation to obtain the hydrogenation feedstock (i.e., a condensation solution containing 3-hydroxybutyraldehyde). The obtained hydrogenation feedstock mainly contained 84.3wt% 3-hydroxybutyraldehyde and 12.5wt% water, with an acid value of 2ppm.

[0154] The hydrogenation reaction and purification process were the same as in Example 2.

[0155] Comparative Example 2

[0156] The same applies to Example 4, and the similarities will not be repeated here. The differences are explained below:

[0157] When preparing the hydrogenation feedstock solution, 50g of sodium hydroxide aqueous solution with a mass concentration of 0.5wt% was added dropwise to 600g of 60wt% acetaldehyde aqueous solution; the final hydrogenation feedstock solution mainly contained 62wt% 3-hydroxybutyraldehyde, with a water content of 36wt% and an acid value of 245ppm.

[0158] The hydrogenation reaction was carried out as in Example 1, except that the hydrogenation temperature was 110°C.

[0159] The refining process is the same as in Example 1.

[0160] Table 1. Peak area ratio, odor evaluation, and crotonaldehyde content of 1,3-butanediol products after storage.

[0161] Table 2 Results of Skin Irritation Tests

[0162] Therefore, it can be seen that the 1,3-butanediol product of the present invention can significantly reduce product odor, and the crotonaldehyde content does not increase significantly during long-term storage, but remains at a low level; the aqueous solution prepared from the 1,3-butanediol product of the present invention has significantly lower or even no skin irritation.

[0163] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A 1,3-butanediol product, characterized in that, In the gas chromatography analysis of the 1,3-butanediol product, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the peak area ratios appearing in the range of relative retention time of 1.32-1.38 is >0 and ≤750ppm. The analytical conditions for the gas chromatography method are as follows: Gas chromatograph: Agilent 7890 gas chromatograph; Detector: Flame Ionization Detector (FID); Chromatographic column: HP-VOC column, column length 60m × inner diameter 0.32mm × film thickness 1.8μm; Carrier gas: nitrogen, flow rate 1.5 ml / min; Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min; Vaporization chamber temperature: 260℃; Detector temperature: 280℃.

2. The 1,3-butanediol product according to claim 1, characterized in that, When the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention times is 5-700 ppm.

3. The 1,3-butanediol product according to claim 2, characterized in that, When the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention times is 10-700 ppm.

4. The 1,3-butanediol product according to any one of claims 1-3, characterized in that, After adjusting the pH of a 50wt% aqueous solution of the 1,3-butanediol product to 6, and storing it at 50°C for 90 days, the crotonaldehyde content does not exceed 10ppm.

5. A humectant comprising the 1,3-butanediol product according to any one of claims 1-4.

6. A cosmetic product comprising the moisturizer of claim 5.

7. A method for improving the odor and / or skin irritation of a composition containing 1,3-butanediol, characterized in that, The added 1,3-butanediol product must meet the following requirements to improve the odor and / or skin irritation of the composition: In the gas chromatography analysis of the 1,3-butanediol product, when the relative retention time corresponding to the peak position of 1,3-butanediol is set to 1.0, the sum of the peak area ratios appearing in the range of relative retention time of 1.32-1.38 is >0 and ≤750ppm. The analytical conditions for the gas chromatography method are as follows: Gas chromatograph: Agilent 7890 gas chromatograph; Detector: Flame Ionization Detector (FID); Chromatographic column: HP-VOC column, column length 60m × inner diameter 0.32mm × film thickness 1.8μm; Carrier gas: nitrogen, flow rate 1.5 ml / min; Column temperature: Initial temperature 50℃, hold for 2 min, then increase to 80℃ at 5℃ / min, then increase to 270℃ at 15℃ / min and hold for 10 min; Vaporization chamber temperature: 260℃; Detector temperature: 280℃.

8. The method according to claim 7, characterized in that, When the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention times is 5-700 ppm.

9. The method according to claim 8, characterized in that, When the relative retention time corresponding to the elution position of 1,3-butanediol is set to 1.0, the sum of the area fractions of the peaks appearing in the range of 1.32-1.38 relative retention times is 10-700 ppm.

10. A method for preparing the 1,3-butanediol article according to any one of claims 1-9, comprising the following steps: S1. Using a feed solution containing 3-hydroxybutyraldehyde as a hydrogenation feed solution, a hydrogenation reaction is carried out to obtain a reaction solution containing 1,3-butanediol. S2. The reaction solution containing 1,3-butanediol is separated and purified to obtain 1,3-butanediol product; in, In step S1, before the hydrogenation reaction is carried out, the acid value of the hydrogenation feed solution is controlled to be 5-200 ppm; Preferably, in the 3-hydroxybutyraldehyde-containing solution, the content of 3-hydroxybutyraldehyde is >20 wt%; Preferably, the water content in the 3-hydroxybutyraldehyde-containing solution is 1-42 wt%.

Images