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Method for preparing methyl ester levulinate by alcoholysis of hexamylose in near-critical methanol

A technology of methyl levulinate and hexavalent sugar alcohol, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of high operating costs, reduce the reaction temperature, shorten the reaction time, The effect of reducing the reaction steps

Inactive Publication Date: 2010-05-19
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Furfuryl alcohol and levulinic acid are also prepared from hexavalent sugars, etc. The best yield of the process from hexavalent sugars to methyl levulinate is 50-60%, but the operation cost is high, and there is an urgent need to improve the existing process

Method used

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  • Method for preparing methyl ester levulinate by alcoholysis of hexamylose in near-critical methanol
  • Method for preparing methyl ester levulinate by alcoholysis of hexamylose in near-critical methanol
  • Method for preparing methyl ester levulinate by alcoholysis of hexamylose in near-critical methanol

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Effect test

Embodiment 1

[0025] Add methanol 300mL, glucose 3g and sulfuric acid (98%) 0.6g (glucose mass concentration is 10g / L, sulfuric acid molar concentration 0.02mol / L) in 500mL intermittent autoclave, replace the air in the kettle with nitrogen after airtight, start stirring ; heat up to 170°C for alcoholysis for 4 hours; after alcoholysis, cool to room temperature, open the exhaust valve to collect dimethyl ether; add sodium bicarbonate aqueous solution to the alcoholysis solution to adjust the pH value to neutral, and distill under normal pressure to remove the low boiling point The product and solvent were then distilled under reduced pressure to obtain 0.61 g of methyl levulinate, with a molar yield of 28.1% and a purity of 98.1% (GC).

Embodiment 2

[0027] Add methanol 300mL, glucose 6g and sulfuric acid (98%) 0.3g (glucose mass concentration is 20g / L, sulfuric acid molar concentration 0.01mol / L) in 500mL intermittent autoclave, replace the air in the kettle with nitrogen after airtight, start stirring ; heat up to 170°C for alcoholysis for 4 hours; after alcoholysis, cool to room temperature, open the exhaust valve to collect dimethyl ether; add sodium bicarbonate aqueous solution to the alcoholysis solution to adjust the pH value to neutral, and distill under normal pressure to remove the low boiling point The product and solvent were then distilled under reduced pressure to obtain 0.94 g of methyl levulinate, with a molar yield of 21.6% and a purity of 98.5% (GC).

Embodiment 3

[0029] Add methanol 300mL, glucose 6g and sulfuric acid (98%) 1.2g (glucose mass concentration is 20g / L, sulfuric acid molar concentration 0.04mol / L) in 500mL intermittent autoclave, replace the air in the kettle with nitrogen after airtight, start stirring ; heat up to 170°C for alcoholysis for 4 hours; after alcoholysis, cool to room temperature, open the exhaust valve to collect dimethyl ether; add sodium carbonate aqueous solution to the alcoholysis solution to adjust the pH value to neutral, and distill off the low boiling point products under normal pressure and solvent, and then distilled under reduced pressure to obtain 1.77 g of methyl levulinate, with a molar yield of 40.7% and a purity of 97.5% (GC).

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Abstract

The invention discloses a method for preparing methyl ester levulinate by the alcoholysis of hexamylose in near-critical methanol. The method comprises the following steps of: (1) adding methanol, hexamylose and an acid catalyst into a high-pressure reaction kettle, replacing air in the kettle by using nitrogen gas after sealing, and stirring, wherein the mass concentration of the hexamylose is 10-120g / L, and the molarity of the acid catalyst is 0.01-0.20mol / L; (2) heating to the temperature of 150-200 DEG C and carrying out alcoholysis for 0.5-11h; (3) after finishing the alcoholysis, cooling to room temperature, opening an exhaust valve and collecting dimethyl ether; and (4) regulating the pH value of alcoholysis liquid to a neutral state, distilling off a product with low boiling point and a solvent by normal-pressure distillation and then decompressing and distilling to obtain the methyl ester levulinate. The invention reduces the purification of levulinate in the traditional process, prepares the methyl ester levulinate directly by a one-step method and has the advantages of simple process, high product yield, low cost, little three wastes and the like.

Description

technical field [0001] The invention relates to a method for preparing esters, in particular to a method for preparing methyl levulinate by alcoholysis of a hexavalent sugar in near-critical methanol. Background technique [0002] Methyl levulinate (Methyl Levulinate, 4-Oxovaleric acid methyl ester, Methyl4-oxovalerate, CAS No: 624-45-3), molecular formula C 6 H 10 O 3 , the structural formula is as follows, a colorless liquid with a density of 1.051 and a boiling point of 193-195°C. [0003] [0004] Methyl levulinate can be directly used as spices, food additives and gasoline additives, and because there is a carbonyl group and an ester group in its structure, the carbon-oxygen double bond on the carbonyl group is a strong polar bond, and the carbon atom is a positive charge center , when the carbonyl reacts, the electrophilic center of the carbon atom plays a decisive role. The carbonyl structure of methyl levulinate allows it to be isomerized to give enol isomers....

Claims

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Application Information

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IPC IPC(8): C07C69/716C07C67/00
Inventor 吕秀阳吴晓宇
Owner ZHEJIANG UNIV
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