Preparation method of 1-bromoethyl acetate

A technology of bromoethyl acetate and acetyl bromide, applied in the field of preparation of 1-bromoethyl acetate, can solve the problems of difficult reaction control, reduced catalysis, low product purity, etc., and achieves low cost and avoidance requirements Effect

Inactive Publication Date: 2013-04-03
GUANGDONG LIGUO PHARMACY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are mainly the following routes for the synthesis of 1-bromoethyl acetate: one is the industrialized use of acetyl bromide and acetaldehyde in the catalyst zinc chloride Under the reaction, 1-bromoethyl acetate is generated. The disadvantage of this process is that the boiling point of acetaldehyde is very low, which makes the reaction difficult to control and brings difficulties to industrial production; acetaldehyde is carcinogenic; zinc chloride is very easy to absorb water and form group, this result greatly reduces its catalytic effect; in addition, the product produced by this process has many impurity components and low product purity
[0005] Chinese patent application CN 102417451 A used a catalyst with a naphthalene ring structure instead of zinc chloride to synthesize (R, S) 1-bromoethyl acetate, The catalyst is more difficult to remove than the zinc salt catalyst, and the product purity is not high
[0006]WO 9855445A1 technology is to obtain target product with vinyl acetate and hydrogen bromide gas reaction, the technology of this reaction is simple raw material is easy to get, but, because hydrogen bromide is The gas makes the reaction difficult to control, the material ratio is not easy to determine, and the utilization rate of the reactant is low, resulting in a low yield of the target product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Add 250mL of acetyl bromide to the reaction flask, add 2.5g of alumina powder (catalyst) while stirring, and cool down to 5°C; after completion, slowly add 10mL of paraldehyde; Heat up to 12°C and continue to stir for 5 hours; after the reaction is complete, remove the solids by filtration; transfer the suction-filtered solution to the reaction flask, add 150ml of dichloromethane under stirring, and continue to maintain the solution temperature at 10°C and stir for 20 minutes; Add 105ml of purified water at 2°C to the reaction bottle, stir and extract for 20 minutes, after completion, let stand to separate, remove the upper aqueous phase to obtain the lower organic phase and transfer it to the reaction bottle; control the inner temperature of the bottle below 25°C, and depressurize Distillation, distilled off fractions, that is, the product 1-bromoethyl acetate. The yield was 79%. Gas chromatography analysis product purity is 90.1%.

Embodiment 2

[0042] Add 250mL of acetyl bromide to the reaction flask, add 2.75g of alumina powder under stirring, and cool down to 8°C; after completion, slowly add 12.5mL of paraldehyde dropwise; The stirring reaction was continued at 15°C for 2 hours.

[0043] After the reaction is complete, remove the solid matter by filtration; transfer the suction-filtered solution to the reaction flask, add 188ml of dichloromethane under stirring, and continue to maintain the solution temperature at 15°C and stir for 20 minutes; add 141ml of purified water at 5°C to the solution, and stir After extraction for 20 minutes, after completion, the layers were separated, and the upper aqueous phase was removed to obtain the lower organic phase, which was then transferred to a reaction flask.

[0044] Then add 141ml of purified water at 5°C to the organic phase in the reaction flask, stir and extract for 20 minutes, leave to stand for stratification, remove the upper phase water phase to obtain the lower p...

Embodiment 3

[0046]Add 250mL of acetyl bromide to the reaction flask, add 3.0g of alumina powder under stirring, and cool down to 10°C; after completion, slowly add 15mL of paraldehyde dropwise; The reaction was continued to stir for 2 hours at °C.

[0047] After the reaction is complete, remove the solid matter by filtration; transfer the suction-filtered solution to the reaction flask, add 200ml of dichloromethane under stirring, and continue to maintain the solution temperature at 18°C ​​and stir for 20 minutes; add 150ml of purified water at 5°C to the solution, and stir After extraction for 20 minutes, after completion, the layers were separated, and the upper aqueous phase was removed to obtain the lower organic phase, which was then transferred to a reaction flask.

[0048] Then add 150ml of purified water at 5°C to the organic phase in the reaction flask, stir and extract for 20 minutes, let stand to separate layers, remove the upper phase water phase to obtain the lower phase orga...

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Abstract

The invention discloses a preparation method of 1-bromoethyl acetate, which comprises the following steps: under the catalysis of aluminum oxide, reacting acetyl bromide with paracetaldehyde; and then, extracting with dichloromethane/water to obtain the high-purity 1-bromoethyl acetate. According to the method, the paracetaldehyde is used instead of acetaldehyde in the traditional process, and the aluminum oxide is used for catalysis preferably, so that the method is environment-friendly, is easy to realize quantification and ensures high yield and purity of the product; and meanwhile, the process conditions of the method are mild and easy to control, thereby being suitable for industrial production.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a preparation method of 1-bromoethyl acetate. Background technique [0002] 1-bromoethyl acetate, also known as 1-bromoethyl acetate, CAS number: 40258-78-4, molecular formula: C 4 h 7 BrO 2 , Molecular weight: 167.0012 The structural formula is , density: 1.496g / cm3, boiling point: 141.555°C, at 760 mmHg, flash point: 68.548°C. Soluble in ethanol, dichloromethane, chloroform and other organic solvents, insoluble in water. [0003] 1-Bromoethyl acetate as a carboxyl group is an important intermediate in organic synthesis, pesticides and other fine synthesis. For example, in the synthesis of cefuroxime axetil, it is necessary to use 1-bromoethyl acetate as the raw material for the esterification of the carboxyl group. Cefuroxime axetil is a synthetic second-generation cephalosporin drug with broad-spectrum, strong bactericidal power, internal stability to β-2 lactamase, an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/63C07C67/14
Inventor 许伟龙
Owner GUANGDONG LIGUO PHARMACY
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