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CN-122010683-A - Preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol

CN122010683ACN 122010683 ACN122010683 ACN 122010683ACN-122010683-A

Abstract

The invention discloses a preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol, belonging to the technical field of organic synthesis. Isobutyraldehyde is used as a raw material, isobutyronitrile is generated by reacting isobutyraldehyde with hydroxylamine hydrochloride in the presence of 1-butyl-3-methylimidazole chloride and a catalyst Bu 4 NPF 6 , then 2-methylpropanoic acid is generated by acidification after alkaline hydrolysis under the action of methyltrichlorosilane and methanol, then 2, 4-tetramethyl-1, 3-cyclobutanedione is generated under the action of a dehydrating agent and triethylamine, and finally bis (2-methoxyethoxy) sodium aluminum hydride is used for reduction to obtain 2, 4-tetramethyl-1, 3-cyclobutanediol. The key point of the route is that 2-methylpropanoic acid generates 2, 4-tetramethyl-1, 3-cyclobutanone under the combined action of a dehydrating agent and triethylamine, and the method is simple and convenient to operate and suitable for industrial production.

Inventors

  • WANG GANG
  • AN YUXIAN

Assignees

  • 大连中科聚合新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (9)

  1. 1. The preparation method of the 2, 4-tetramethyl-1, 3-cyclobutanediol is characterized by comprising the following steps: ; A. Mixing isobutyraldehyde, hydroxylamine hydrochloride, [ BMIm ] Cl and Bu 4 NPF 6 in an organic solvent, and reacting at a heating condition to generate isobutyronitrile; B. mixing isobutyronitrile in methanol, dropwise adding methyltrichlorosilane at low temperature, performing alkaline hydrolysis after the reaction is finished, and then performing acidification to obtain 2-methylpropanoic acid; C. Mixing a dehydrating agent and organic base in dichloromethane, adding a dichloromethane solution of 2-methylpropanoic acid at low temperature, and then heating to react to obtain 2, 4-tetramethyl-1, 3-cyclobutanone; D. Mixing 2, 4-tetramethyl-1, 3-cyclobutanedione in toluene, and adding sodium bis (2-methoxyethoxy) aluminum hydride at low temperature to generate 2, 4-tetramethyl-1, 3-cyclobutanediol.
  2. 2. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in the step A, the organic solvent is selected from DMAc, DMF or DMSO, and the heating condition is 50-90 ℃.
  3. 3. The method for producing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in step A, the molar ratio of isobutyraldehyde, hydroxylamine hydrochloride, [ BMIm ] Cl to Bu 4 NPF 6 is 1:1-1.2:1-1.2:0.02-0.06.
  4. 4. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in the step B, the alkali is selected from sodium hydroxide or potassium hydroxide solution, the acid is selected from hydrochloric acid or sulfuric acid, and the temperature is-5 ℃ to 5 ℃.
  5. 5. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in step B, the molar ratio of isobutyronitrile to methyltrichlorosilane is 1:0.4-1.
  6. 6. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in the step C, the dehydrating agent is selected from 2-chloro-1, 3-dimethylimidazolinium chloride or N, N' -dicyclohexylcarbodiimide, the organic base is selected from triethylamine or diisopropylethylamine, and the low temperature is-20 ℃ to 10 ℃.
  7. 7. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in step C, the molar ratio of the 2-methylpropanoic acid, the dehydrating agent and the organic base is 1:1-1.2:0.005-0.015.
  8. 8. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in step D, the low temperature is-40 to 0 ℃.
  9. 9. The method for preparing 2, 4-tetramethyl-1, 3-cyclobutanediol according to claim 1, wherein in step D, the molar ratio of 2, 4-tetramethyl-1, 3-cyclobutanedione to sodium bis (2-methoxyethoxy) aluminum hydride is 1:1-3.

Description

Preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol Technical Field The invention relates to a preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol, belonging to the technical field of organic synthesis. Background 2, 4-Tetramethyl-1, 3-Cyclobutanediol (CBDO) is an important organic polymer raw material. The method is mainly used for synthesizing high-performance polyester materials, has high glass transition temperature, chemical resistance and high transparency, and is widely applied to the fields of household appliances, automobiles, food packaging and the like. Domestic enterprises such as the Wanhua chemical group are also pushing pilot-scale and industrialization cooperation of related technologies by the us isman chemical company monopolizing the production technology. The safety aspect of the composition is that the half lethal dose LD50 of acute oral toxicity of rats is 1500 mg/kg, belongs to low-toxicity substances, and has no genetic toxicity. In food contact materials, both national and European regulations authorize their use as monomers or starting materials for the production of plastic food contact materials and articles. CBDO has fewer synthesis methods, and representative routes include patents [ CN112457170A; CN105732329A; US2017/334815A1; KR2019/56665A ] report that 2, 4-tetramethyl-1, 3-cyclobutanone is adopted as a raw material, and a product CBDO is obtained through reduction reaction, wherein the chemical reaction equation is as follows: The synthesis method of 2, 4-tetramethyl-1, 3-cyclobutanone mainly comprises the following two routes, patent and literature [ CN 112457170A; HELVETICA CHIMICA ACTA, 1999, 82, 1302; KR2024/61949A; CN11966131A ] report that isobutyryl chloride is adopted as a raw material, and dehydrochlorination is carried out under the action of triethylamine to generate dimethylketene, and then polycondensation cyclization reaction is carried out to generate 2, 4-tetramethyl-1, 3-cyclobutanone, wherein the chemical reaction equation is as follows: Patent [ CN105732354A; KR2019/56665A; CN113443976A ] reports that 2-methylpropanoic acid or 2-methylpropanoic anhydride is adopted as a raw material, and is subjected to high-temperature catalytic cracking to generate dimethylketene, and then is subjected to polycondensation cyclization reaction to generate 2, 4-tetramethyl-1, 3-cyclobutanone. In view of the drawbacks of the above-described technical routes, there is a need for intensive research into the synthetic route of CBDO to provide an updated process route to meet the increasing market demand. Disclosure of Invention In order to overcome the technical defects, the invention provides a preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol. The technical scheme includes that isobutyraldehyde is used as a raw material, isobutyronitrile is generated by reacting isobutyraldehyde with hydroxylamine hydrochloride under the action of 1-butyl-3-methylimidazole chloride and a catalyst Bu 4NPF6, then 2-methylpropanoic acid is generated by acidification after alkaline hydrolysis under the action of methyltrichlorosilane and methanol, then 2, 4-tetramethyl-1, 3-cyclobutanedione is generated under the action of a dehydrating agent and triethylamine, and finally sodium bis (2-methoxyethoxy) aluminum hydride is used for reduction to obtain 2, 4-tetramethyl-1, 3-cyclobutanediol. The method has reasonable route and four steps, and provides a simple and effective brand new route for preparing the 2, 4-tetramethyl-1, 3-cyclobutanediol. The invention relates to a preparation method of 2, 4-tetramethyl-1, 3-cyclobutanediol, which has the following reaction equation: the method comprises the following steps: A. Mixing isobutyraldehyde, hydroxylamine hydrochloride, [ BMIm ] Cl and Bu 4NPF6 in an organic solvent, and reacting at a heating condition to generate isobutyronitrile; B. mixing isobutyronitrile in methanol, dropwise adding methyltrichlorosilane at low temperature, performing alkaline hydrolysis after the reaction is finished, and then performing acidification to obtain 2-methylpropanoic acid; C. Mixing a dehydrating agent and organic base in dichloromethane, adding a dichloromethane solution of 2-methylpropanoic acid at low temperature, and then heating to react to obtain 2, 4-tetramethyl-1, 3-cyclobutanone; D. Mixing 2, 4-tetramethyl-1, 3-cyclobutanedione in toluene, and adding sodium bis (2-methoxyethoxy) aluminum hydride at low temperature to generate 2, 4-tetramethyl-1, 3-cyclobutanediol. Further, in the step A, the organic solvent is selected from DMAc, DMF or DMSO, and the temperature rising condition is 50-90 ℃. Further, in the step A, the molar ratio of the isobutyraldehyde, the hydroxylamine hydrochloride, the [ BMIm ] Cl and the Bu 4NPF6 is 1:1-1.2:1-1.2:0.02-0.06. Further, in the step B, the low temperature condition is-5 ℃ to 5 ℃. Further, in the step B, the molar ratio of the isobutyronitrile to the methyltrichlorosilane is 1:0.4-1. Further, in