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CN-122029143-A - Method for producing 1, 3-butanediol and products thereof

CN122029143ACN 122029143 ACN122029143 ACN 122029143ACN-122029143-A

Abstract

The present invention relates to a process for preparing 1, 3-butanediol comprising (a) stripping acetaldehyde from a crude mixture comprising aldol acetaldehyde and water at a temperature in the range of 80 ℃ to 90 ℃ to produce concentrated aldol, (b) hydrogenating the concentrated aldol to produce crude 1, 3-butanediol, and (C) subjecting the crude 1, 3-butanediol to azeotropic distillation. The process of the present invention reduces the hydrogen consumption in step (b) and further reduces the impurities causing color and odor. The invention also relates to 1, 3-butanediol having a low concentration of color and odor causing impurities.

Inventors

  • R. Garde
  • S. Pagar
  • S. SRIVASTAVA

Assignees

  • 戈达瓦里生物炼制有限责任公司

Dates

Publication Date
20260512
Application Date
20241017
Priority Date
20231018

Claims (14)

  1. 1. A process for preparing 1, 3-butanediol, the process comprising: a. Stripping acetaldehyde from a crude mixture comprising aldol acetaldehyde and water at a temperature in the range of 80 ℃ to 90 ℃ to produce concentrated aldol, B. hydrogenating the concentrated butyl aldol to produce crude 1, 3-butanediol, and C. Subjecting the crude 1, 3-butanediol to azeotropic distillation.
  2. 2. The method according to claim 1, comprising preparing the crude mixture by aldol condensation of acetaldehyde in an aqueous medium until less than 60 wt.% of the acetaldehyde is converted to aldol, and neutralizing the crude mixture by adding an organic acid selected from acetic acid, propionic acid or butyric acid to a pH having an acid content of up to 0.5 wt.% or in the range of 5 to 6.
  3. 3. The process of claim 1, wherein the crude mixture in step (a) comprises 25 to 30 wt.% acetaldehyde and 40 to 50 wt.% of aldol.
  4. 4. The method of claim 1, wherein step (a) is performed at a temperature in the range of 88 ℃ to 90 ℃.
  5. 5. The process of claim 1, wherein the concentrated aldol comprises 60 to 65 wt.% aldol and 8 to 10 wt.% or 10 to 12 wt.% acetaldehyde.
  6. 6. The process of claim 1, wherein step (b) is performed with hydrogen in the presence of a raney nickel catalyst in the range of 0.1 wt% to 1 wt% at a pressure in the range of 10 to 25 atmospheres and at a temperature in the range of 55 ℃ to 120 ℃.
  7. 7. The process of claim 6, wherein step (b) is performed with hydrogen in an amount of 0.65 m 3 /kg of 1, 3-butanediol product.
  8. 8. The process of claim 1 wherein azeotropic distillation is performed by adding 0.2 to 0.4 parts of water per 1 part of 1, 3-butanediol in the distillate.
  9. 9. The method of claim 1, wherein the 1, 3-butanediol has a purity in the range of 99.50% to 99.85%.
  10. 1, 3-Butanediol comprising less than or equal to 0.002% ethanol, less than or equal to 0.01% each of acetic acid and 2-ethylbutanol, less than 0.5% water, and less than 0.05% of a mixture comprising n-butanol, 1, 3-butanediol acetate, 1, 3-dioxane-2-heptyl-4-methyl, 2-methyl-1- [1- (2-methylbutoxy) ethoxy ] butane, hexanol, and 2, 4-pentanediol-3-methyl.
  11. 11. The 1, 3-butanediol of claim 10 comprising less than 0.5 ppm of acetaldehyde, less than 5 ppm of crotonaldehyde, greater than 0ppm to 10ppm or less of hydride of acetaldehyde trimer, 50ppm or less of acetal of 1, 3-butanediol and butyl aldehyde, and 50ppm or less of ester of acetic acid and 1, 3-butanediol.
  12. 12. The 1, 3-butanediol of claim 11 characterized by gas chromatographic analysis, the hydride of the acetaldehyde trimer having a Relative Retention Time (RRT) of 0.65, the acetals of 1, 3-butanediol and the aldol of butanol having a RRT of 2.3 to 2.4, the esters of acetic acid and 1, 3-butanediol having a RRT of 1.35 to 1.45, The conditions of the gas chromatography are that Analytical column A column (film thickness 1.0 μm, length 30m, and inner diameter 0.25 mm) with dimethylpolysiloxane as stationary phase, Heating conditions from 80 to 120 ℃ at 5 ℃ per minute, then again to 160 ℃ and holding for 2 minutes at 2 ℃ per minute, and further to 230 ℃ at 10 ℃ per minute and holding for 18 minutes at 230 ℃, The sample introduction temperature was 250C, Carrier gas helium, column gas flow rate 1 mL/min, and Detector and detection temperature Flame Ionization Detector (FID), 280 ℃.
  13. 13. The 1, 3-butanediol according to claim 10 or 11, having a color of 10 on the American Public Health Association (APHA) color scale and being odorless.
  14. 14. A personal care composition comprising the 1, 3-butanediol according to any one of the preceding claims 10 to 13.

Description

Method for producing 1, 3-butanediol and products thereof Technical Field The present invention relates to a process for preparing 1, 3-butanediol and products thereof. Background 1, 3-Butanediol is viscous, colorless, transparent, highly hygroscopic and has a low odor. It has a wide range of applications, for example the production of chemically stable derivatives, as solvents for the coating industry, as monomers for various synthetic resins, and as chain extenders (chain extenders). 1, 3-butanediol also has excellent moisturizing properties, and thus, its demand in the cosmetic industry is increasing. 1, 3-Butanediol is generally produced by any one of the three known methods described below. First, a process in which, first, a aldol (acetaldol, 3-hydroxybutyraldehyde) is prepared by aldol condensation of acetaldehyde and then catalytic hydrogenation is performed using a raney nickel (RANEY NICKEL) metal catalyst to obtain 1, 3-butanediol. Further, purification of the obtained 1, 3-butanediol is performed by conventional distillation to separate odor-causing impurities. In addition, the method requires the addition of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, or an alkali metal borohydride such as sodium borohydride to remove impurities having high boiling points. The disadvantage of this process is that it is a batch process, in particular the hydrogenation step of the aldol and the purification of the 1, 3-butanediol are carried out in batch mode, the hydrogen consumption in the hydrogenation step is high and the odor-causing impurities are not completely removed by conventional distillation. Second, a method for preparing 1, 3-butanediol by hydration reaction of 1, 3-epoxybutane. The process is not used for the industrial manufacture of 1, 3-butanediol. Third, a process for preparing 1, 3-butanediol from propylene and formaldehyde by the Prince reaction. The process produces 1, 3-butanediol in low yields. JP 4397495 discloses a process for the production of 1, 3-butanediol, wherein the aldol between butanols is catalytically hydrogenated under acidic conditions to prevent corrosion of the equipment. However, this method requires the addition of alkali metal hydroxide and alkali metal borohydride to remove impurities having high boiling points. The acetaldehyde used in the aldol condensation reaction to make the aldol enters the aldol product stream so that the crude product may contain up to 50 wt.% (%wt.) of more acetaldehyde, which is not present in free form, but is reversibly bound to the aldol itself. When heated to higher temperatures, such as in a hydrogenation step, the presence of acetaldehyde causes the decomposition of the aldol to crotonaldehyde. The following prior art mentions the separation of acetaldehyde from aldol. WO 2005/068408 describes a process for the preparation of 1, 3-butanediol using acetaldehyde with a low concentration of carboxylic acid (up to 0.04%). This application describes a process step wherein after aldol condensation, the product stream is treated with an acid to neutralize the alkaline reagent used in aldol condensation and a stripping distillation column is used to separate the aldol and acetaldehyde. However, in this document, the 1, 3-butanediol obtained after hydrogenation is subjected to further distillation and vacuum distillation steps to purify the product. US 2521204 describes a process for concentrating butyl aldol. The process involves neutralizing crude butyl aldol to a pH in the range of 6.5 to 7.5. The crude aldol is then passed over a surface heated to a temperature of 90 ℃ to 110 ℃ in the form of a liquid free-flowing film to separate acetaldehyde by evaporation. WO 2005/068408 and US 2521204 do not teach the removal of impurities from 1, 3-butanediol. Japanese patents JP 6979473 and JP 6979544 describe 1, 3-butanediol products in which after their synthesis the 1, 3-butanediol is subjected to further steps of dehydration, desalination, distillation, basification, dealkalization and dehydration. The 1, 3-butanediol product has a high content of hydrides of acetaldehyde trimer and acetal compounds of 1, 3-butanediol and butanediol aldehyde. None of the above applications describe a process wherein hydrogen consumption is reduced during the hydrogenation step. Accordingly, there is a need for an improved process for the preparation of 1, 3-butanediol with reduced hydrogen consumption during the hydrogenation step and further removal of color and odor causing impurities. Disclosure of Invention In one aspect, the present invention relates to a method of preparing 1, 3-butanediol, the method comprising: a. Stripping (STRIPPING OFF) acetaldehyde from a crude mixture comprising aldol acetaldehyde and water at a temperature in the range of 80 ℃ to 90 ℃ to produce concentrated aldol, B. hydrogenating the concentrated butyl aldol to produce crude 1, 3-butanediol, and C. Subjecting the crude 1, 3-butanediol to azeotropic di