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Preparation method of 4-bromine-3-methyl-2-butene-1-alcohol acetate

A technology of alcohol acetate and methyl, applied in the field of preparation of 4-bromo-3-methyl-2-buten-1-ol acetate, can solve low product yield and excess isoprene Many problems, low safety operation coefficient, etc., to achieve the effect of simple post-treatment process, increased reaction rate, and high product yield

Active Publication Date: 2019-09-17
南京瑞鼎生物医药有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] 1. There is a lot of excess isoprene, and there is a lot of waste of raw materials
[0009] 2. Bromosuccinimide needs to be added in batches, isoprene is flammable and explosive, and the safety operation coefficient is low;
[0010] 3. The post-treatment process is complex and produces a large amount of waste water;
[0011] 4. Additional rearrangement reactions are required to convert isomers into products;
[0012] 5. The product yield is low, only about 78%;
[0013] 6. Unable to achieve large-scale and continuous production

Method used

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  • Preparation method of 4-bromine-3-methyl-2-butene-1-alcohol acetate

Examples

Experimental program
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Effect test

Embodiment 1

[0041] 187g of bromosuccinimide solid particles were charged into the tube reactor, with a volume of about 100ml. Weigh 68g of isoprene and 20g of water, start the metering pump to continuously pump the materials in, the flow rate of the pump is 40ml / h, and control the reaction temperature to 0°C. The reaction is over, and the gas phase detection isoprene reaction is complete, and rectification in a rectification tower obtains 110.8g of rectification products (4-bromo-3-methyl-2-butene-1-alcohol and 1-bromo-2-methyl -3-buten-2-ol), the yield was 92%. After mixing 110.8g of rectified products and 100g of acetic anhydride, pump them into a pipeline reactor filled with 100g of D001 type strongly acidic cation exchange resin, the pump flow rate is 50ml / h, and the esterification rearrangement reaction temperature is 100°C. At the end of the reaction, there is no 1,2-addition isomer in the gas phase detection. First, the acetic acid and unreacted acetic anhydride generated by the r...

Embodiment 2

[0043] 190 g of bromosuccinimide solid particles are charged into the tube reactor, with a volume of about 100 ml. Weigh 68g of isoprene and 25g of water, start the metering pump to continuously pump the materials in, the flow rate of the pump is 50ml / h, and control the reaction temperature to 5°C. The reaction is over, and the gas phase detection isoprene reaction is complete, and rectification in a rectification tower obtains 108.5g rectification products (4-bromo-3-methyl-2-butene-1-alcohol and 1-bromo-2-methyl -3-buten-2-ol), the yield is 90%. After mixing 108.5g of rectified product and 105g of acetic anhydride, pump them into a pipeline reactor filled with 100g of 732 type strong acid cation exchange resin, the pump flow rate is 20ml / h, and the esterification rearrangement reaction temperature is 80°C. At the end of the reaction, there is no 1,2-addition isomer in the gas phase detection. First, the acetic acid and unreacted acetic anhydride generated by the reaction ar...

Embodiment 3

[0045] 187g of bromosuccinimide solid particles were charged into the tube reactor, with a volume of about 100ml. Weigh 68g of isoprene and 20g of water, start the metering pump to continuously pump the materials in, the flow rate of the pump is 20ml / h, and control the reaction temperature to 10°C. The reaction is over, and the gas phase detection isoprene reaction is complete, and rectification in a rectification tower obtains 113g rectification products (4-bromo-3-methyl-2-butene-1-alcohol and 1-bromo-2-methyl- 3-buten-2-ol), yield 93.8%. After mixing 113g of rectified products and 110g of acetic anhydride, pump them into a pipeline reactor filled with 100g of 732 type strongly acidic cation exchange resin, the pump flow rate is 40ml / h, and the esterification rearrangement reaction temperature is 90°C. At the end of the reaction, there is no 1,2-addition isomer in the gas phase detection. First, the acetic acid and unreacted acetic anhydride generated by the reaction are re...

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Abstract

The invention discloses a preparation method of 4-bromine-3-methyl-2-butene-1-alcohol acetate. The method comprises the following steps that a mixture of isoprene and water is continuously pumped into a first reactor filled with bromo-succinimide to perform bromine alcoholization reaction; after rectification by a first rectification device, rectification products of 4-bromine-3-methyl-2-butene-1-alcohol and 1-bromine-2-methyl-3-butene-2-alcohol are obtained; a mixture of the rectification products and acetic anhydride is continuously pumped into a second reactor filled with solid acid catalysts for performing esterification rearrangement reaction; reaction liquid is obtained; the reaction liquid is subjected to reduced pressure distillation to recover acetic acid and unreacted acetic anhydride; through rectification by a second rectification device, the 4-bromine-3-methyl-2-butene-1-alcohol acetate is obtained. The preparation method of the 4-bromine-3-methyl-2-butene-1-alcohol acetate has the advantages that the product yield is high; the continuous and scaled production can be easily realized.

Description

technical field [0001] The invention relates to a preparation method of 4-bromo-3-methyl-2-buten-1-ol acetate, which belongs to the technical field of preparation of pharmaceutical intermediates. Background technique [0002] 4-Bromo-3-methyl-2-buten-1-ol acetate is an important intermediate in the production of vitamin A and its derivatives. The molecular formula of 4-bromo-3-methyl-2-buten-1-ol acetate is as follows: [0003] [0004] It is mentioned in the patent US4175204 that after adding isoprene to glacial acetic acid and stirring evenly, bromosuccinimide is added in batches to carry out normal temperature reaction. The methane phase was washed with sodium carbonate aqueous solution and sodium chloride aqueous solution, added anhydrous magnesium sulfate to dry, filtered, dichloromethane was recovered by distillation under reduced pressure, and the product 4-bromo-3-methyl-2-butene-1- Alcohol acetate and the 1,2 addition isomer 1-bromo-2-methyl-2-acetoxy-3-butene,...

Claims

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Application Information

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IPC IPC(8): C07C67/04C07C67/293C07C69/145
CPCC07C29/64C07C67/04C07C67/293C07C33/423C07C69/145
Inventor 张磊伏大进苗雨沁
Owner 南京瑞鼎生物医药有限公司
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