CN1453263A

CN1453263A - Synthesis of gamma-ethyl bromo-butyrate

Info

Publication number: CN1453263A
Application number: CN 03119092
Authority: CN
Inventors: 胡先明; 付潮; 滕汉斌; 邱国福; 粱淑彩
Original assignee: Wuhan University WHU
Current assignee: Wuhan University WHU
Priority date: 2003-05-19
Filing date: 2003-05-19
Publication date: 2003-11-05
Anticipated expiration: 2023-05-19
Also published as: CN1218927C

Abstract

Ethyl gamma-bromobutyrate is synthesized with gamma-butyrolactone in ethanol through reaction with HBr, which is produced directly through the reaction between gamma-butyrolactone and ethanol. On finishing the reaction, the product is treated with icy dilute alkali solution, dried with drying agent and distilled to obtain the destination product ethyl gamma-bromobutyrate. The said process has yield up to 85-90 %, simple operation, easy control, stable yield, low cost and no environmental pollution.

Description

Synthesis method of gamma-ethyl bromobutyrate

Technical Field

The invention relates to a synthesis method of gamma-ethyl bromobutyrate.

Background

The molecular formula of the gamma-bromobutyrate Ethyl esteris C₆H₁₁BrO₂Molecular weight of 195.01, boiling point of 98-99 deg.C (25mm), and refractive index of n²⁵D1.4543, a commonly used synthetic intermediate, widely used in organic synthesisAnd (4) in the process of becoming medium. A method for synthesizing gamma-ethyl bromobutyrate from cyanogen bromide was reported in 1955. The method has multiple synthesis steps and uses hypertoxic substances containing cyanide; another method is to introduce HBr gas into a mixed solution of gamma-butyrolactone and absolute ethanol for reaction, which requires absolute absence of water from the raw materials, requires a long reaction time, and wastes raw materials.

Disclosure of Invention

The invention aims to solve the problem of providing a synthesis method of gamma-ethyl bromobutyrate, which has the advantages of simple operation, easy control, short reaction time and low preparation cost.

The technical scheme provided by the invention is as follows: the synthesis method of the gamma-ethyl bromobutyrate directly adds the inorganic raw materials of red phosphorus and bromine required for generating hydrogen bromide gas into the mixed solution of the gamma-butyrolactone and the absolute ethyl alcohol, controls the reaction temperature to be-10 to 50 ℃, and just promotes the organic reaction by taking water generated by the organic reaction of the whole system as the reactant of the inorganic reaction. The reaction equation is as follows:

the invention preferably controls the reaction temperature to be 0-15 ℃, so that the reaction is favorable for the generation of products, the reaction yield is favorably improved, and the occurrence of side reactions is controlled. After the reaction is finished, treating the mixed solution with dilute alkali ice water, separating an organic layer and a water layer, drying the organic layer by using a drying agent such as a molecular sieve or anhydrous sodium sulfate, and distilling to obtain the required gamma-ethyl bromobutyrate.

The invention has the main advantages that:

(1) in the method, HBr gas is directly generated in the reaction mixed liquid, and a special gas generating device is not needed for operation

The operation is simple and convenient, and the control is easy; the reaction time is shortened, the cost is low, no pollution is caused, and the requirements of green chemistry are met.

(2) The method has low requirements on the quality of the raw materials, and can be applied to common chemically pure or industrial raw materials.

(3) The reaction temperature of the method is controlled to be 0-15 ℃, so that the reaction is favorable for the generation of products and the reduction of

The production of by-products improves the quality of the product.

(4) The method of the invention uses dilute alkali ice water for post-treatment, so that the product is easy to separate and purify. By gas chromatographic analysis, the by-product table

If no or only trace by-product peak exists, the product content is generally over 98 percent, and the yield is 85 to 90 percent.

Detailed Description

The present invention will be further described with reference to the following specific examples.

Example 1

17.2 g (0.2mol) of gamma-butyrolactone, 41.0ml (0.7mol) of absolute ethyl alcohol and 6.2 g (0.2mol) of red phosphorus are added into a 100ml flask equipped with an electromagnetic stirring, a constant pressure funnel and an exhaust gas receiving tube, the flask is kept at 0 ℃ in a salt ice water bath, electromagnetic stirring is started, a mixed solution of 16.0ml (0.3mol) of bromine and 7.2ml of water is dripped, 5-6ml is dripped within the first 10 minutes, and the rest is dripped for about 5 hours. After the solution was left at 0 ℃ for 24 hours, it was poured into 100ml of 2.0% sodium carbonate ice water, the organic layer and the aqueous layer were separated, the aqueous layer was extracted twice with chloroform, and combined with the organic layer, washed with 0 ℃ 2.0% sodium carbonate solution, 0.5% HCl solution and water, dried over anhydrous sodium sulfate, chloroform was distilled off, and reduced pressure distillation was carried out to obtain 35.5 g (yield 90%) of gamma-ethyl bromobutyrate as a colorless liquid product. n is²⁵D1.4539 (literature value n)²⁵D1.4543), IR-and-mixing of the product¹HNMR confirmed.

Example 2

In a 250ml flask equipped with an electromagnetic stirrer, a constant pressure funnel and an off-gas receiver, 34.4 g (0.4mol) of gamma-butyrolactone, 80.0ml (1.4mol) of absolute ethanol, 12.4 g (0.4mol) of red phosphorus were added, the flask was maintained at 10 ℃, stirred by electromagnetic stirring was started, a mixture of 32.0ml (0.6mol) of bromine and about 14ml of water was added dropwise, and the mixture was stirred at the beginning with 1 ml of water15ml of the solution is added dropwise within 0 minute, and the rest 5 to 6 hours is added. The whole reaction mixture system is poured into 200ml of 2.0% sodium carbonate ice water, an organic layer and a water layer are separated, the water layer is extracted twice by chloroform and is combined with the organic layer, themixture is washed by 2.0% sodium carbonate solution at 0 ℃, 0.5% HCl solution and water, the mixture is dried by a molecular sieve, chloroform is evaporated, and the colorless liquid product, namely, 68.2 g of gamma-ethyl bromobutyrate (yield is 87%) is obtained by reduced pressure distillation. n is²⁵D1.4539 (literature value n)²⁵D1.4543)。

Example 3

25.8 g (0.3mol) of gamma-butyrolactone, 61.5ml (1.0mol) of absolute ethyl alcohol and 9.3 g (0.3mol) of red phosphorus are added into a 250ml flask equipped with an electromagnetic stirring, a constant pressure funnel and an exhaust gas receiving tube, the temperature is kept at 15 ℃, electromagnetic stirring is started, a mixed solution of 24.0ml (0.45mol) of bromine and about 10ml of water is dripped, 8ml is dripped within the first 10 minutes, and the rest is dripped within about 5-6 hours. The whole reaction mixture system is poured into 200ml of 2.0% sodium carbonate ice water, an organic layer and a water layer are separated, the water layer is extracted twice by chloroform and is combined with the organic layer, the mixture is washed by 2.0% sodium carbonate solution at 0 ℃, 0.5% HCl solution and water, the mixture is dried by a molecular sieve, chloroform is evaporated, and the colorless liquid product, namely the gamma-ethyl bromobutyrate, is obtained by reduced pressure distillation (yield 86%). n is²⁵D1.4539 (literature value n)²⁵D1.4543)。

Example 4

1.37kg (16mol) of gamma-butyrolactone, 3.2L (56mol) of absolute ethanol and 500 g (16.3mol) of red phosphorus are added to a 10L flask equipped with an electromagnetic stirrer, a constant pressure funnel and an off-gas receiving tube, the flask is kept at 10 ℃, electromagnetic stirring is started, a mixed solution of 1.28L (24mol) of bromine and about 550ml of water is dropwise added, 600ml is dropwise added within the first 10 minutes, and the rest is dropped within about 5 to 6 hours. The whole reaction mixed system is poured into 10L of 2.0% sodium carbonate ice water, an organic layer and a water layer are separated, the water layer is extracted twice by chloroform and is combined with the organic layer, the mixture is washed by 2.0% sodium carbonate solution at 0 ℃, 0.5% HCl solution and water in sequence, the mixture is dried by a molecular sieve, chloroform is evaporated, and the colorless liquid product, namely 2.7kg of gamma-ethyl bromobutyrate (yield 86%) is obtained by reduced pressure distillation. n is_D ²⁵1.4539 (literature value n)_D ²⁵1.4543)。

Claims

1. The synthesis method of the gamma-ethyl bromobutyrate comprises the steps of adding red phosphorus into a mixed solution of gamma-butyrolactone and absolute ethyl alcohol, dropwise adding bromine under stirring, controlling the reaction temperature to be-10-50 ℃, and collecting a product from a reaction mixture after the reaction is finished to obtain the gamma-ethyl bromobutyrate.

2. The method of claim 1, further comprising: the reaction temperature is controlled to be 0-15 ℃.

3. The method according to claim 1 or 2, wherein: and collecting the product from the reaction mixture by treating the mixed solution after the reaction with dilute alkali ice water, separating an organic layer and a water layer, drying the organic layer with a drying agent, and distilling to obtain the required gamma-ethyl bromobutyrate.

4. The method of claim 3, further comprising: the drying agent is molecular sieve or anhydrous sodium sulfate.