Method for reducing impurities contained in acetaldehyde feed stream during production of 1,3-butanediol product

Abstract

The present invention belongs to the technical field of cosmetic-grade 1,3-butanediol products, and particularly relates to a method for reducing impurities contained in the acetaldehyde feed stream during the production of a cosmetic-grade 1,3-butanediol product. With regard to the storage of the acetaldehyde feed stream as a raw material, the storage period is greater than 0 and less than or equal to 90 days; the storage temperature is greater than 0 and less than or equal to 50℃; the storage is carried out under air-excluded conditions; and the content of polyacetaldehyde in the acetaldehyde feed stream as a raw material is greater than 0 and less than or equal to 2 wt%. According to the present invention, an odorless cosmetic-grade 1,3-butanediol product with low skin sensitization can be obtained.

Description

Methods for reducing impurities in acetaldehyde feedstock during the production of 1,3-butanediol products Technical Field

[0001] This invention belongs to the technical field of cosmetic-grade 1,3-butanediol products, and particularly relates to a method for reducing impurities in acetaldehyde feedstock during the production of cosmetic-grade 1,3-butanediol products. Background Technology

[0002] 1,3-Butanediol (1,3-BG) exhibits the reactivity of diols. Its industrial-grade products can be used as raw materials for polyester resins and alkyd resins. Many of its monocarboxylic acid monoesters are excellent plasticizers for PVC resins and plastics. 1,3-BG can also react with monomers such as phthalic anhydride and maleic anhydride to produce unsaturated polyester resins. Due to its antibacterial properties, 1,3-BG is also used as an antibacterial agent in dairy and meat products. 1,3-BG has very low toxicity to higher animals, comparable to that of glycerin. In the cosmetics industry, 1,3-BG, due to its transparency, colorlessness, and extremely mild odor, has long been used by formulators as a high-end moisturizer. It can also be used as a skin emollient, solvent, and fragrance co-solvent.

[0003] In cosmetic applications, 1,3-butanediol products with minimal odor (industrial grade) are required. 1,3-Butanediol itself is almost odorless, but it can develop an odor due to byproducts or impurities generated during the manufacturing process.

[0004] Generally, 1,3-butanediol products are manufactured by condensing acetaldehyde to obtain butanol (3-hydroxybutanol), followed by hydrogenation. However, during the reaction, due to the instability of the raw materials, they easily polymerize to form characteristic substances such as paraacetaldehyde. These substances, such as impurities A (triacetaldehyde) and B (tetraacetaldehyde) with the structures shown below, can cause off-odors in the resulting 1,3-butanediol products.

[0005] Patent document CN 113557221A discloses a method for controlling the odor of 1,3-butanediol products using distillation, but odor impurities are not completely removed; when the 1,3-butanediol product is prepared as an aqueous solution, an off-odor still exists. Patent document CN115400706A discloses a method for removing odors using steam distillation, but this process is cumbersome and energy-intensive, making it unsuitable for large-scale industrial production. Patent document CN114890869A discloses a process for removing odors using esterification and extraction, but the reaction steps are cumbersome and introduce new impurities, resulting in a final 1,3-butanediol product that fails to meet requirements. Patent document WO200302753A discloses a method for obtaining 1,3-butanediol products with less odor using extraction. The organic solvent used as the extractant can be ketones. However, 1,3-butanediol products obtained by extraction also have the problem of difficulty in completely eliminating odor and the generation of a slight odor after long-term storage. In addition, due to the introduction of the extractant, the residue of the extractant can lead to skin sensitization problems when using 1,3-butanediol products in the cosmetics field.

[0006] In summary, there is an urgent need to develop and research odorless cosmetic-grade 1,3-butanediol products with low skin sensitization that can be applied in the cosmetics field. Summary of the Invention

[0007] To address the problems existing in the prior art, the purpose of this invention is to provide a method for reducing the impurities contained in acetaldehyde feedstock during the production process of cosmetic-grade 1,3-butanediol products; cosmetic-grade 1,3-butanediol products obtained by this impurity reduction method are odorless and will not develop odor due to long-term storage, and have low skin sensitization.

[0008] After in-depth research, the inventors discovered that impurities such as paraacetaldehyde exist in the 1,3-butanediol products produced. By controlling the storage conditions of the acetaldehyde raw material used in the preparation of 1,3-butanediol products, the concentration of paraacetaldehyde impurities in the 1,3-butanediol products can be controlled below a certain level, thus obtaining odorless cosmetic-grade 1,3-butanediol products that do not produce odor after long-term storage. The entire modification process does not introduce sensitizing substances and has low skin sensitization.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for reducing impurities in acetaldehyde feedstock during the production of cosmetic-grade 1,3-butanediol products.

[0011] During the storage of acetaldehyde as a raw material, the storage time is greater than 0 and less than or equal to 90 days (e.g., 0.5 days, 1 day, 2 days, 4 days, 5 days, 8 days, 10 days, 15 days, 20 days, 25 days, 30 days, 35 days, 40 days, 50 days, 55 days, 60 days, 70 days, 80 days, 85 days); and the storage temperature is greater than 0 and less than or equal to 50℃ (e.g., 1℃, 2℃, 5℃, 6℃, 8℃, 10℃, 12℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 48℃).

[0012] Acetaldehyde, as a raw material, is stored in an airtight manner during storage.

[0013] According to the method provided by the present invention, in some embodiments, the acetaldehyde material stream used as raw material is stored for a period of greater than 0 and less than or equal to 45 days, preferably greater than 0 and less than or equal to 15 days.

[0014] In some implementation schemes, the acetaldehyde feedstock used as a raw material is stored at a temperature greater than 0°C and less than or equal to 30°C.

[0015] In some implementation schemes, the acetaldehyde feedstock, as a raw material, is stored using nitrogen-sealed storage (i.e., nitrogen-sealed storage).

[0016] In this paper, the content of paraacetaldehyde in the acetaldehyde stream used as a raw material can be controlled within a suitable range by the method described above. According to the method provided by the present invention, in some embodiments, the content of paraacetaldehyde in the acetaldehyde stream used as a raw material is greater than 0 and less than or equal to 2 wt% (e.g., 0.001 wt%, 0.002 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.008 wt%, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%).

[0017] According to the method provided by the present invention, in some embodiments, the content of paraacetaldehyde in the acetaldehyde stream as a raw material is greater than 0 and less than or equal to 1 wt%, preferably greater than 0 and less than or equal to 0.5 wt%.

[0018] In this paper, by controlling the storage conditions of the acetaldehyde raw material as described above, the concentration of paraacetaldehyde impurities in the obtained 1,3-butanediol product can be controlled within a certain range. According to the method provided by the present invention, in some embodiments, the 1,3-butanediol product comprises 1,3-butanediol and paraacetaldehyde;

[0019] When the content of polyacetaldehyde in the 1,3-butanediol product was detected using headspace thermal desorption-mass spectrometry (HDS-MS), and the relative retention time of 1,3-butanediol in the 1,3-butanediol product was set to 1.0, the sum of the peak areas appearing in the range of 0.86 to 0.88 was greater than 0 and less than or equal to 100 ppb (e.g., 1 ppb, 2 ppb, 5 ppb, 10 ppb, 20 ppb, 30 ppb, 40 ppb, 50 ppb, 60 ppb, 70 ppb, 80 ppb, 90 ppb, 92 ppb, 95 ppb, 98 ppb); and

[0020] The component corresponding to the peak appearing in the relative retention time range of 0.86 to 0.88 is paraacetaldehyde.

[0021] According to the method provided by the present invention, in some embodiments, when the relative retention time of 1,3-butanediol in the 1,3-butanediol product is set to 1.0, the sum of the area values ​​of the peaks appearing in the range of 0.86 to 0.88 is greater than 0 and less than or equal to 80 ppb; preferably greater than 0 and less than or equal to 50 ppb.

[0022] In some implementations, headspace thermal desorption-gas chromatography-mass spectrometry (HCGS) is used to detect the paraacetaldehyde content in the 1,3-butanediol product, including:

[0023] The HSTD headspace thermal desorption multi-functional sampler can be used: Chengdu Kelin Analytical Technology Co., Ltd.

[0024] (1) Conditions for headspace

[0025] Furnace temperature: 70℃

[0026] Needle temperature: 100℃,

[0027] Transmission temperature: 200℃;

[0028] Pressure displacement time: 30s;

[0029] Injection time: 120s;

[0030] Air defense time: 30s;

[0031] Temperature control time: 30 min;

[0032] Cycle time: 42 min;

[0033] Pressure: 120 kPa;

[0034] Carrier gas: Helium;

[0035] (2) Conditions for thermal desorption

[0036] Purging time: 60s;

[0037] First-order desorption time: 2.1 min;

[0038] Heating time for cold hydrazine: 8.0 min;

[0039] Injection time: 100s;

[0040] Cycle time: 43 min;

[0041] Secondary desorption temperature: 300℃;

[0042] First-stage desorption temperature: 110℃;

[0043] Cold hydrazine adsorption temperature: -30℃;

[0044] Valve temperature: 200℃;

[0045] Transmission temperature: 220℃;

[0046] Carrier gas pressure: 100 kPa;

[0047] Adsorption flow rate: 35 mL / min;

[0048] Flow rate of split 1: 5 mL / min;

[0049] Flow rate of split 2: 5 mL / min;

[0050] (3) Conditions for gas chromatography analysis

[0051] The gas chromatograph that can be used is the Shimadzu GC-2010Plus gas chromatograph.

[0052] Analytical column: HP-VOC (60m in length, 0.32mm in inner diameter, 1.8μm in film thickness) manufactured by Agilent Technologies was used as the gas chromatography column, with (6% cyanopropyl-phenyl)-methylpolysiloxane as the stationary phase;

[0053] Carrier gas: Helium;

[0054] Carrier gas flow rate: 1.5 mL / min;

[0055] Control mode: Constant velocity flow;

[0056] Vaporization chamber temperature: 250℃;

[0057] Heating conditions: The initial column temperature is set to 50℃, held for 2 minutes, then increased to 80℃ at a rate of 5℃ / min, then increased to 260℃ at a rate of 15℃ / min, and held at 240℃ for 15 minutes.

[0058] Flow split ratio: No flow split;

[0059] (4) Conditions for mass spectrometry analysis

[0060] Available mass spectrometer: Shimadzu GCMS-QP2020 mass spectrometer;

[0061] Ionization mode: EI; Measurement type: Full scan;

[0062] Ion source temperature: 230℃;

[0063] Quadrupole temperature: 150℃;

[0064] Electron energy: 70 eV;

[0065] Scan start quality: 29;

[0066] Finished scan quality: 600;

[0067] Calibration curve: When using metaldehyde standard solution to prepare data analysis, extractive ion chromatogram (EIC) was used to confirm the EIC peak area (EIC: m / z 89) of metaldehyde in the range of 0.86 to 0.88 relative retention time when the relative retention time of 1,3-butanediol was set to 1.0.

[0068] (5) Preparation of standard solutions and plotting of standard curves

[0069] Add metaldehyde to water to prepare a metaldehyde standard solution with a concentration range of 10-100 μg / L; use a 10 mL pipette to transfer 10 mL of the prepared standard solution into a 20 mL headspace sample bottle, seal it, and perform the test according to steps (1) to (4);

[0070] In SCAN mode, gas-mass spectra were obtained. Characteristic ions 89 and 117 were extracted to determine the retention position of metaldehyde. The peak of characteristic ion 89 was integrated to plot a standard curve.

[0071] (6) Testing of the sample to be tested

[0072] Weigh 2g (accurate to 0.1mg) of the 1,3-butanediol product to be tested into a 20mL headspace sample vial. Use a 10mL pipette to transfer 8mL of ultrapure water into the headspace vial, seal it, and perform the test according to steps (1) to (4).

[0073] The 1,3-butanediol product of this invention contains a paraacetaldehyde compound as the component corresponding to the peak appearing in the relative retention time range of 0.86 to 0.88. The paraacetaldehyde compound may have, but is not limited to, the following structures:

[0074] In some embodiments of the method provided by the present invention, the paraacetaldehyde is triacetaldehyde and / or tetraacetaldehyde.

[0075] According to the method provided by the present invention, in some embodiments, the 1,3-butanediol product is prepared by acetaldehyde condensation hydrogenation process;

[0076] The content of polyacetaldehyde in the acetaldehyde stream used as a raw material is greater than 0 and less than or equal to 2 wt% (e.g., 0.001 wt%, 0.002 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.008 wt%, 0.01 wt%, 0.02 wt%, 0.04 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%), preferably greater than 0 and less than or equal to 1 wt%, more preferably greater than 0 and less than or equal to 0.5 wt%.

[0077] The preparation method of the 1,3-butanediol product can employ the conventional acetaldehyde condensation and hydrogenation process in this field.

[0078] In this invention, the preparation method of the 1,3-butanediol product can be a known technique, for example, reference to patents CN110790634B, US5345004, US6376725, US6900360, and CN1558890A.

[0079] In some specific implementations, the preparation method may include, for example, the following steps:

[0080] 1) Acetaldehyde condensation: In the presence of an alkaline catalyst (such as aqueous sodium hydroxide solution or aqueous potassium hydroxide solution, generally aqueous sodium hydroxide solution), acetaldehyde undergoes a condensation reaction to obtain a reaction mixture containing 3-hydroxybutyraldehyde; then, unreacted acetaldehyde is removed by nitrogen stripping or short-path evaporation to obtain a hydrogenation feedstock solution; wherein, the condensation reaction temperature can be 0-30℃, preferably 10-15℃ (e.g., 12℃, 13℃, 14℃); the reaction time can be a conventional selection in the art;

[0081] 2) Hydrogenation step: The hydrogenation feed solution obtained in step 1) is subjected to a hydrogenation reaction to obtain a 1,3-butanediol reaction solution. The hydrogenation catalyst is selected from catalysts containing nickel and / or cobalt (such as Raney nickel, Raney cobalt, supported nickel and supported cobalt catalysts). The reaction temperature can be 110-130℃, for example, 115℃, 120℃, 125℃, and the reaction pressure can be 2-20MPa (gauge pressure), for example, 4MPa, 5MPa, 8MPa, 10MPa, 12MPa, 15MPa, 18MPa. The reaction space velocity can be a conventional choice in the art, which will not be elaborated here.

[0082] 3) Separation step: The 1,3-butanediol reaction solution obtained in step 2) is separated by distillation and deodorized to obtain cosmetic grade 1,3-butanediol products; wherein, the distillation separation operation and its process conditions and deodorization treatment can be conventional methods in the field, and will not be described in detail here.

[0083] The source of the acetaldehyde stream used as a raw material in the manufacture of the 1,3-butanediol product described in this invention is not particularly limited. Examples include acetaldehyde streams synthesized from ethanol oxidation and acetaldehyde streams synthesized from ethylene oxidation. Preferably, the acetaldehyde stream used as a raw material is the acetaldehyde stream synthesized from ethanol obtained through bio-fermentation through further oxidation.

[0084] The inventors' research revealed that the polyacetaldehyde compounds contained in 1,3-butanediol products are mainly introduced by the acetaldehyde feedstock as a raw material. The amount produced during the condensation and hydrogenation process of the acetaldehyde feedstock is relatively small. Therefore, it is necessary to control the polyacetaldehyde content in the acetaldehyde feedstock to be no higher than 2 wt%.

[0085] Acetaldehyde, as a raw material, is unstable. During storage, excessively high temperatures, prolonged storage time, or exposure to air can cause polymerization reactions, generating polyacetaldehyde compounds such as triacetaldehyde or tetraacetaldehyde. This can further introduce polyacetaldehyde into 1,3-butanediol products, leading to residual polyacetaldehyde that affects the product's odor and may cause skin sensitization. To meet the usage requirements of the acetaldehyde raw material, in some embodiments, the acetaldehyde raw material used in the preparation method of the 1,3-butanediol product is stored for a period greater than 0 and less than or equal to 90 days, preferably greater than 0 and less than or equal to 45 days, and more preferably greater than 0 and less than or equal to 15 days.

[0086] In some embodiments, in the method for preparing the 1,3-butanediol product, the acetaldehyde feedstock used as a raw material is stored at a temperature greater than 0 and less than or equal to 50°C, preferably greater than 0 and less than or equal to 30°C.

[0087] In some embodiments, in the method for preparing the 1,3-butanediol product, the acetaldehyde feedstock used as a raw material is stored in an air-isolated manner, preferably by nitrogen sealing.

[0088] This invention controls the content of paraacetaldehyde in the acetaldehyde raw material by controlling the storage method and conditions of the acetaldehyde stream. This ensures that the content of paraacetaldehyde compounds in the final 1,3-butanediol product is less than 100 ppb or even undetectable. The resulting cosmetic-grade 1,3-butanediol product meets downstream requirements for odor detection and skin sensitization. Detailed Implementation

[0089] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0090] In the following examples and comparative examples, the sources of some reagents or raw materials used, unless otherwise specified, are all conventional products that can be purchased commercially.

[0091] [Odor Test]

[0092] For the 1,3-butanediol products prepared in each embodiment and comparative example, odor tests were conducted according to the following evaluation method.

[0093] (1) Methods for evaluating odor:

[0094] The 1,3-butanediol products prepared in each example and comparative example were mixed with water to prepare 10g of aqueous solutions with a 10wt% content of 1,3-butanediol product. These solutions were then added to 20mL wide-mouth glass bottles, the caps were closed, and the mixture was stirred vigorously at room temperature for 1 minute. The caps were then opened and the odor was smelled. The odor level of the sample was compared with that of a standard odor sample to determine the odor level. Ten evaluators were selected, and the average score of each evaluator's evaluation results was calculated as the odor score.

[0095] (2) Preparation of standard odor samples:

[0096] 1,3-Butanediol manufactured by Daicel was mixed with water to prepare a 10wt% 1,3-butanediol aqueous solution as a standard odor sample. According to Table 1 below, 100g of each of the five standard samples with different odor intensities were prepared and then placed into 200ml wide-mouth flasks.

[0097] Table 1. Odor Standard Samples and Their Corresponding Odor Levels

[0098] (3) Evaluation results of odor

[0099] The standard odor sample prepared in step (2) above was scored as 5. Then, based on the standard odor sample, the odor level of the 1,3-butanediol products prepared in each example and comparative example was evaluated according to the process described in step (1).

[0100] Odor level:

[0101] Level 1: I can smell a foul odor;

[0102] Level 2: Between 1 and 3;

[0103] Level 3: A faint odor is detected;

[0104] Level 4: Between 3 and 5;

[0105] Level 5: No odor detected.

[0106] [Skin sensitization test]

[0107] For the 1,3-butanediol products obtained in each embodiment and comparative example, the skin sensitization was evaluated according to the following procedures.

[0108] (1) Preparation of test substances:

[0109] If the suspected sensitizing substance is a liquid, dilute it with gradient concentrations and then perform a patch test, gradually increasing the concentration; for cosmetics and topical medications, the patch can be applied directly; 30 people are randomly selected as samples.

[0110] (2) Perform patch test:

[0111] Use a commercially available aluminum dish and attach it to a non-allergenic porous adhesive tape. When applying, prepare an appropriate concentration of the suspected sensitizer and place a small amount of the suspected sensitizer in the aluminum dish. Then apply the dish to both sides of the back or the inner side of the forearm. Observe the reaction after 48 hours. However, if irritation or a positive reaction occurs within 48 hours, remove the test substance immediately. If multiple suspected substances are being tested simultaneously, they should be arranged in rows in sequence and marked. Generally, observe for 2-3 consecutive days.

[0112] (3) Result determination:

[0113] Negative: - indicates a negative result; there was no reaction at the application site on the patient.

[0114] Suspicious positive: ± indicates suspicion, with symptoms such as itching or slight redness;

[0115] Weak positive: + indicates a weak positive result, manifested as simple erythema, with symptoms such as itching;

[0116] Positive: ++ indicates a positive result, manifested as redness, swelling, and papules;

[0117] Strong positive: +++ indicates a strong positive result, characterized by significant redness and swelling, with symptoms such as papules and vesicles;

[0118] Extremely positive: ++++ This indicates an extremely positive result, manifested as significant redness, swelling, blisters, and erosion.

[0119] [The impurity content in acetaldehyde raw materials was tested using GC analysis.]

[0120] Analytical apparatus: Agilent Technologies 8890A gas chromatograph system;

[0121] Sample preparation: Dilute the acetaldehyde sample to be tested with ethanol to 2 mL, and then use the diluted solution as the test sample;

[0122] Detector: FID flame ionization detector;

[0123] Detection temperature: 260℃;

[0124] Sample inlet temperature: 260℃;

[0125] Analytical column: HP-INNOWAX (60m length, 0.250mm inner diameter, 0.25μm film thickness) manufactured by Agilent Technologies was used as the gas chromatography column;

[0126] Heating conditions: The initial column temperature is set to 50℃, held for 0.5 min, then increased to 200℃ at a rate of 15℃ / min, then increased to 240℃ at a rate of 20℃ / min, and held at 240℃ for 20 min.

[0127] Control mode: Constant velocity flow;

[0128] Flow split ratio: 50:1;

[0129] Injection volume: 0.2 μL;

[0130] Nitrogen flow rate: 30 mL / min;

[0131] Hydrogen flow rate: 40 mL / min;

[0132] Airflow rate: 400 mL / min;

[0133] Exhaust gas purging rate: 25 ml / min.

[0134] In the above GC analysis, the sum of the peak areas appearing in the range of 2.0 to 2.5 relative residence times when the relative retention time of pure acetaldehyde is set to 1.0 is determined as the percentage of impurities in the acetaldehyde sample to be tested.

[0135] The purity of 1,3-butanediol products was tested using GC analysis.

[0136] Analytical apparatus: Agilent Technologies 8890A gas chromatograph system;

[0137] Sample preparation: Dilute the 1,3-butanediol sample to 2 mL with ethanol, and use the diluted solution as the test sample;

[0138] Detector: FID flame ionization detector;

[0139] Detection temperature: 260℃;

[0140] Sample inlet temperature: 260℃;

[0141] Analytical column: HP-INNOWAX (60m length, 0.250mm inner diameter, 0.25μm film thickness) manufactured by Agilent Technologies was used as the gas chromatography column;

[0142] Heating conditions: The initial column temperature is set to 50℃, held for 0.5 min, then increased to 200℃ at a rate of 15℃ / min, then increased to 240℃ at a rate of 20℃ / min, and held at 240℃ for 20 min.

[0143] Control mode: Constant velocity flow;

[0144] Flow split ratio: 50:1;

[0145] Injection volume: 0.2 μL;

[0146] Nitrogen flow rate: 30 mL / min;

[0147] Hydrogen flow rate: 40 mL / min;

[0148] Airflow rate: 400 mL / min;

[0149] Exhaust gas purging rate: 25 ml / min.

[0150] In the above GC analysis, the area normalization method was used to determine the percentage of the peak area of ​​1,3-butanediol.

[0151] [Detection of paraacetaldehyde content in 1,3-butanediol products using headspace thermal desorption-gas chromatography-mass spectrometry]

[0152] 1.1 HSTD Headspace Thermal Desorption Multifunctional Sampler: Chengdu Kelin Analytical Technology Co., Ltd.;

[0153] (1) Headspace conditions

[0154] Furnace temperature: 70℃;

[0155] Needle temperature: 100℃;

[0156] Transmission temperature: 200℃;

[0157] Pressure displacement time: 30s;

[0158] Injection time: 120s;

[0159] Air defense time: 30s;

[0160] Temperature control time: 30 min;

[0161] Cycle time: 42 min;

[0162] Pressure: 120 kPa;

[0163] Carrier gas: Helium;

[0164] (2) Thermal desorption conditions

[0165] Purging time: 60s;

[0166] First-order desorption time: 2.1 min;

[0167] Heating time for cold hydrazine: 8.0 min;

[0168] Injection time: 100s;

[0169] Cycle time: 43 min;

[0170] Secondary desorption temperature: 300℃;

[0171] First-stage desorption temperature: 110℃;

[0172] Cold hydrazine adsorption temperature: -30℃;

[0173] Valve temperature: 200℃;

[0174] Transmission temperature: 220℃;

[0175] Carrier gas pressure: 100 kPa;

[0176] Adsorption flow rate: 35 mL / min;

[0177] Split 1: 5 mL / min;

[0178] Split 2: 5 mL / min;

[0179] 1.2 Gas Chromatography Analysis: Shimadzu GC-2010 Plus Gas Chromatograph

[0180] Analytical column: HP-VOC (60m in length, 0.32mm in inner diameter, 1.8μm in film thickness) manufactured by Agilent Technologies was used as the gas chromatography column, with (6% cyanopropyl-phenyl)-methylpolysiloxane as the stationary phase;

[0181] Carrier gas: Helium;

[0182] Carrier gas flow rate: 1.5 mL / min;

[0183] Control mode: Constant velocity flow;

[0184] Vaporization chamber temperature: 250℃;

[0185] Heating conditions: The initial column temperature is set to 50℃, held for 2 minutes, then increased to 80℃ at a rate of 5℃ / min, then increased to 260℃ at a rate of 15℃ / min, and held at 240℃ for 15 minutes.

[0186] Flow split ratio: No flow split;

[0187] 1.3 Mass Spectrometry Detection: Shimadzu GCMS-QP2020 Mass Spectrometer

[0188] Ionization mode: EI;

[0189] Measurement type: Full scan;

[0190] Ion source temperature: 230℃;

[0191] Quadrupole temperature: 150℃;

[0192] Electron energy: 70 eV;

[0193] Scan start quality: 29;

[0194] Finished scan quality: 600;

[0195] Calibration curve: A calibration curve was prepared using metaldehyde standards;

[0196] During data analysis, extracted ion chromatograms (EIC) were used to confirm the EIC peak area (EIC: m / z 89) of parethaldehyde when the relative retention time of 1,3-butanediol was set to 1.0 and the relative retention time was between 0.86 and 0.88.

[0197] 1.4 Preparation of standard solutions and plotting of standard curves

[0198] Add metaldehyde to water to prepare a metaldehyde standard solution with a concentration range of 10-100 μg / L; use a 10 mL pipette to transfer 10 mL of the prepared standard solution into a 20 mL headspace sample vial, seal it, and perform the test according to the above steps;

[0199] In SCAN mode, the gas chromatography-mass spectra are obtained. Characteristic ions 89 and 117 are extracted to determine the retention position of metaldehyde. The peak of characteristic ion 89 is integrated to plot a standard curve.

[0200] 1.5 Sample Testing

[0201] Weigh 2g (accurate to 0.1mg) of the 1,3-butanediol product prepared in each example and comparative example as the test sample and place it in a 20mL headspace sample vial. Use a 10mL pipette to transfer 8mL of ultrapure water into the headspace vial, seal it, and perform the test according to the procedures described in 1.1 to 1.3 above.

[0202] Refining of acetaldehyde raw materials:

[0203] Commercially available acetaldehyde streams are 40% (w / w) aqueous solutions. To obtain high-purity acetaldehyde streams, the commercially available acetaldehyde aqueous solution needs to be purified by distillation. The specific steps are as follows:

[0204] Add 500g of 40% acetaldehyde aqueous solution to a 1000mL three-necked flask, place a magnetic inlet inside, and put the flask in a constant-temperature oil bath. Connect the two side openings of the three-necked flask to a ground glass thermometer sleeve (temperature range 200℃) and a ground glass stopper, respectively, and connect the middle opening to a distillation column. The distillation column is filled with θ-ring packing, equivalent to 10 theoretical plates, and the distillation process is carried out at atmospheric pressure. The product collection bottle is a 500mL jacketed flask. The distillation head shell and the jacketed flask are connected in series and then connected to a low-temperature constant-temperature cold bath, the temperature of which is set to 0℃.

[0205] Turn on the constant temperature cold bath. After the temperature drops to 0℃, set the oil bath temperature to 80℃ and turn on the stirring and heating. Set the reflux ratio controller to full reflux. After the oil bath temperature reaches 80℃, the thermometer indicates a temperature of 75℃. When condensate appears at the top of the distillation column, the top temperature is 21℃. At this time, adjust the reflux ratio to 1:1 and start collecting the purified acetaldehyde feed and set it aside.

[0206]

Example 1

[0207] 1. Storage of acetaldehyde as a raw material:

[0208] Fresh, refined acetaldehyde streams were placed in pressure-resistant containers, purged with nitrogen, and stored at 30°C for 15 days. Afterward, the streams were removed from the pressure-resistant containers, and the content of paraacetaldehyde in the refined acetaldehyde streams before and after storage was analyzed using GC analysis. The results showed that before storage, the paraacetaldehyde content in the refined acetaldehyde streams was 0.001 wt%, and after storage, the paraacetaldehyde content was 0.3 wt%.

[0209] 2. Preparation of cosmetic-grade 1,3-butanediol products:

[0210] (S1) Acetaldehyde condensation step

[0211] Add 50g of 1wt% sodium hydroxide aqueous solution to 500g of the purified acetaldehyde stream obtained above over a period of 4 hours. Control the condensation reaction temperature at 10-15℃ using a cold bath. Continue the reaction for 3 hours after the addition is complete. Then add acetic acid to the system to neutralize the material. Recover the unreacted acetaldehyde by short-path evaporation to obtain the hydrogenated feed liquid (i.e., the condensation liquid containing 3-hydroxybutyraldehyde).

[0212] (S2) Hydrogenation step

[0213] 356.7g of the hydrogenation feed solution (a condensate containing 3-hydroxybutyraldehyde) and 12.49g of Raney nickel catalyst (Raney 6800, purchased from GRACE) were placed in a 1L reactor and hydrogenation was carried out at a reaction temperature of 125℃ and a reaction pressure of 15MPa (gauge pressure). After the reaction was completed, crude hydrogenation reaction solution was obtained.

[0214] (S3) Separation and purification steps

[0215] The crude hydrogenation reaction solution obtained above is passed into a distillation column for distillation separation. The distillation column has 30 trays. First, low-boiling-point compounds such as ethanol and water are collected under a pressure of 20 kPa. Then, the pressure is reduced to 2.0 kPa (absolute pressure) to collect 1,3-butanediol product with a purity ≥99.7%.

[0216] 100g of the 1,3-butanediol product obtained by distillation, 100g of water, and 60g of methyl isobutyl ketone were added to a 500mL 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 added to the separated aqueous layer, and the same phase separation operation was repeated twice. The extracted aqueous layer was added to a three-necked flask and dehydrated and concentrated for 30 minutes at an oil bath temperature of 150℃ and a pressure of 8kPa to obtain 95g of the 1,3-butanediol product.

[0217] 3. Performance Testing:

[0218] The content of paraacetaldehyde in the 1,3-butanediol product was detected by headspace thermal desorption-gas chromatography-mass spectrometry. The test results showed that the sum of the peak area values ​​appearing in the range of relative retention time of 0.86 to 0.88 accounted for 46 ppb, and the components corresponding to the peaks appearing in the range of relative retention time of 0.86 to 0.88 were paraacetaldehyde compounds.

[0219] The purity of the obtained 1,3-butanediol product was tested by GC analysis. The results showed that the peak area of ​​1,3-butanediol was 99.86%.

[0220] The odor test of the obtained 1,3-butanediol product showed that the odor score was 5.

[0221] Skin sensitization tests were conducted on the obtained 1,3-butanediol product, and the results showed that all 30 individuals tested negative.

[0222]

Examples 2-6

[0223] 1. Storage of acetaldehyde as a raw material:

[0224] The storage container and storage method are the same as in Example 1, except that the storage temperature and storage time are changed. Please see Table 2 for specific conditions.

[0225] 2. Preparation of cosmetic-grade 1,3-butanediol products:

[0226] The preparation process and steps are the same as in Example 1.

[0227] 3. Performance Testing:

[0228] The testing steps were the same as in Example 1, and the results are shown in Table 3.

[0229]

Comparative Example 1

[0230] 1. Storage of acetaldehyde as a raw material:

[0231] The storage container, storage method, and storage conditions are the same as in Example 1, except that the storage temperature is replaced with 70°C.

[0232] 2. Preparation of cosmetic-grade 1,3-butanediol products:

[0233] The preparation process and steps are the same as in Example 1.

[0234] 3. Performance Testing:

[0235] The testing steps were the same as in Example 1, and the results are shown in Table 3.

[0236] [Comparative Example 2]

[0237] 1. Storage of acetaldehyde as a raw material:

[0238] The storage container, storage method, and storage conditions are the same as in Example 1, except that the storage time is replaced with 180 days.

[0239] 2. Preparation of cosmetic-grade 1,3-butanediol products:

[0240] The preparation process and steps are the same as in Example 1.

[0241] 3. Performance Testing:

[0242] The testing steps were the same as in Example 1, and the results are shown in Table 3.

[0243] [Comparative Example 3]

[0244] 1. Storage of acetaldehyde as a raw material:

[0245] The storage container, storage method, and storage conditions are the same as in Example 1, except that the storage container is not purged with nitrogen.

[0246] 2. Preparation of cosmetic-grade 1,3-butanediol products:

[0247] The preparation process and steps are the same as in Example 1.

[0248] 3. Performance Testing:

[0249] The testing steps were the same as in Example 1, and the results are shown in Table 3.

[0250] Table 2. Storage conditions and results of acetaldehyde feedstock in Examples 2-6 and Comparative Examples 1-3.

[0251] Table 3. Test results of the 1,3-butanediol products obtained in Examples 2-6 and Comparative Examples 1-3.

[0252] By controlling the storage method and conditions of the acetaldehyde feedstock as a raw material, the embodiments of the present invention achieve control over the content of polyacetaldehyde in the acetaldehyde feedstock, thereby ensuring that the content of polyacetaldehyde compounds in the final 1,3-butanediol product is less than 100 ppb or even undetectable; this ensures that the odor evaluation and skin sensitization of the obtained cosmetic-grade 1,3-butanediol product can meet the downstream requirements.

[0253] Comparative Examples 1-3 failed to properly control the storage method and conditions of the acetaldehyde raw material, resulting in a high content of polyacetaldehyde compounds in the final 1,3-butanediol products, exceeding 150 ppb, and even reaching 500-800 ppb or more. This seriously affected the odor evaluation and skin sensitization of the obtained cosmetic-grade 1,3-butanediol products, and failed to meet downstream requirements.

[0254] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.

Claims

1. A method for reducing impurities in acetaldehyde feedstock during the production of cosmetic-grade 1,3-butanediol products, characterized in that, During the storage of acetaldehyde as a raw material, the storage time is greater than 0 and less than or equal to 90 days, preferably greater than 0 and less than or equal to 45 days, and more preferably greater than 0 and less than or equal to 15 days; the storage temperature is greater than 0 and less than or equal to 50°C, preferably greater than 0 and less than or equal to 30°C. When storing acetaldehyde as a raw material, the storage method should be to isolate it from air, preferably using nitrogen sealing.

2. The method according to claim 1, characterized in that, In the acetaldehyde stream used as a raw material, the content of polyacetaldehyde is greater than 0 and less than or equal to 2 wt%, preferably greater than 0 and less than or equal to 1 wt%, and more preferably greater than 0 and less than or equal to 0.5 wt%.

3. The method according to claim 1 or 2, characterized in that, The 1,3-butanediol product comprises 1,3-butanediol and polyacetaldehyde; When the content of polyacetaldehyde in the 1,3-butanediol product was detected using headspace thermal desorption-gas chromatography-mass spectrometry (HCGS), and the relative retention time of 1,3-butanediol in the 1,3-butanediol product was set to 1.0, the sum of the peak areas appearing in the range of 0.86 to 0.88 was greater than 0 and less than or equal to 100 ppb; and The component corresponding to the peak appearing in the relative retention time range of 0.86 to 0.88 is paraacetaldehyde.

4. The method according to claim 3, characterized in that, When the relative retention time of 1,3-butanediol in the 1,3-butanediol product is set to 1.0, the sum of the area values ​​of the peaks appearing in the range of 0.86 to 0.88 is greater than 0 and less than or equal to 80 ppb; preferably greater than 0 and less than or equal to 50 ppb.

5. The method according to claim 3 or 4, characterized in that, The content of paraacetaldehyde in the 1,3-butanediol product was determined by headspace thermal desorption-gas chromatography-mass spectrometry, which included: (1) Conditions for headspace Furnace temperature: 70℃; Needle temperature: 100℃; Transmission temperature: 200℃; Pressure displacement time: 30s; Injection time: 120s; Air defense time: 30s; Temperature control time: 30 min; Cycle time: 42 min; Pressure: 120 kPa; Carrier gas: Helium; (2) Thermal desorption conditions Purging time: 60s; First-order desorption time: 2.1 min; Heating time for cold hydrazine: 8.0 min; Injection time: 100s; Cycle time: 43 min; Secondary desorption temperature: 300℃; First-stage desorption temperature: 110℃; Cold hydrazine adsorption temperature: -30℃; Valve temperature: 200℃; Transmission temperature: 220℃; Carrier gas pressure: 100 kPa; Adsorption flow rate: 35 mL / min; Split 1: 5 mL / min; Split 2: 5 mL / min; (3) Conditions for gas chromatography analysis Carrier gas: Helium; Carrier gas flow rate: 1.5 mL / min; Control mode: Constant velocity flow; Vaporization chamber temperature: 250℃; Heating conditions: The initial column temperature is set to 50℃, held for 2 minutes, then increased to 80℃ at a rate of 5℃ / min, then increased to 260℃ at a rate of 15℃ / min, and held at 240℃ for 15 minutes. Flow split ratio: No flow split; (4) Conditions for mass spectrometry analysis Ionization mode: EI; Measurement type: Full scan; Ion source temperature: 230℃; Quadrupole temperature: 150℃; Electron energy: 70 eV; Scan start quality: 29; Finished scan quality: 600; (5) Preparation of standard solutions and plotting of standard curves Add metaldehyde to water to prepare a metaldehyde standard solution with a concentration range of 10-100 μg / L; use a 10 mL pipette to transfer 10 mL of the prepared standard solution into a 20 mL headspace sample bottle, seal it, and perform the test according to steps (1) to (4); In SCAN mode, gas-mass spectra were obtained. Characteristic ions 89 and 117 were extracted to determine the retention position of metaldehyde. The peak of characteristic ion 89 was integrated to plot a standard curve. (6) Testing of the sample to be tested Weigh 2g of the 1,3-butanediol product to be tested into a 20mL headspace sample vial. Use a 10mL pipette to transfer 8mL of ultrapure water into the headspace vial, seal it, and perform the test according to steps (1) to (4).

6. The method according to any one of claims 2-5, characterized in that, The polyacetaldehyde is triacetaldehyde and / or tetraacetaldehyde.

7. The method according to any one of claims 1-6, characterized in that, The 1,3-butanediol product is prepared by acetaldehyde condensation and hydrogenation process. The content of polyacetaldehyde in the acetaldehyde feedstock as raw material is greater than 0 and less than or equal to 2 wt%, preferably greater than 0 and less than or equal to 1 wt%, and more preferably greater than 0 and less than or equal to 0.5 wt%.

8. The method according to claim 7, characterized in that, In the method for preparing the 1,3-butanediol product, the acetaldehyde feedstock used as a raw material is stored for a period of greater than 0 and less than or equal to 90 days, preferably greater than 0 and less than or equal to 45 days, and more preferably greater than 0 and less than or equal to 15 days; and / or When storing acetaldehyde as a raw material, the storage temperature is greater than 0 and less than or equal to 50°C, preferably greater than 0 and less than or equal to 30°C.

9. The method according to claim 7 or 8, characterized in that, In the preparation method of the 1,3-butanediol product, the acetaldehyde material used as raw material is stored in an air-isolated manner, preferably by nitrogen sealing.

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