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Novel method for preparing 4-acetoxy-2-methyl-2-butenal

A technology of acetoxy and crotonaldehyde, which is applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds, etc., can solve the high requirements for the storage of intermediates and the safety of the reaction, and a large number of by-products. , low yield and other problems, to achieve the effect of easy to achieve industrial production, mild reaction conditions and environmental friendliness

Active Publication Date: 2018-12-14
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, the preparation technology of 4-acetoxy-2-methyl-2-butenal is mainly divided into three categories: 1) using ethylene oxide as a starting material, the main disadvantage is: a large amount of unstable intermediates will be produced , there are higher requirements for the storage of intermediates and the safety of the reaction; 2) using dimethoxyacetone as the starting material, the main disadvantages are: the route is long, the yield is low, and a large amount of by-products are produced; 3) Using isoprene and sodium hypochlorite as starting materials, the main disadvantages are: a large amount of waste water will be generated, and the pollution is serious
This method consumes a large amount of expensive organic phosphine reagents, and the reaction selectivity of acrolein and ethylene oxide is difficult to control

Method used

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Experimental program
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Effect test

Embodiment 1

[0058] Add 2500g of methanol, 500g of tiglic aldehyde, and 0.5g of p-toluenesulfonic acid into a 5L reactor, stir, raise the temperature to 65°C, and reflux for 1h. After the reaction was completed, it was cooled to room temperature. After the reaction solution is adsorbed by the basic resin to remove the catalyst, the methanol is rectified to obtain the acetal (I) with a yield of 98%.

[0059] Add 1040g of acetonitrile, 260g of acetal (I), 2g of cuprous chloride, and 32g of 2,2'-bipyridine into a 2L three-necked flask. Stir, cool to 5°C, add dropwise 528g of tert-butyl peroxyacetate solution, and control the temperature of the reaction solution to 0°C. After the dropwise addition was completed, the reaction was continued at 0°C for 1 h. After the reaction was finished, samples were taken for gas phase analysis, and the yield was calculated to be 86% according to the analysis results. The acetal ester (II) was obtained by rectification and separation with a purity of >99%. ...

Embodiment 2

[0063] Add 2500g methanol, 250g tiglic aldehyde, 2.5g LaCl in the 5L reactor 3 , stirred, heated to 65°C, and refluxed for 5h. After the reaction was completed, it was cooled to room temperature. After the reaction solution was adsorbed by the basic resin to remove the catalyst, the methanol was rectified to obtain the acetal (I) with a yield of 97%.

[0064] Add 1560g of DMF, 260g of acetal (I), 17.4g of cuprous trifluoromethanesulfonate, and 14.6g of 1,10-phenanthroline into a 5L three-necked flask. Stir, adjust the temperature to 20°C, add dropwise 1056g of tert-butyl peroxyacetate solution, and control the temperature of the reaction solution to 20°C. After the dropwise addition was completed, the reaction was continued at 20°C for 5h. After the reaction was completed, samples were taken for gas phase analysis, and the yield was calculated to be 89% according to the analysis results. The acetal ester (II) was obtained by rectification and separation with a purity of >9...

Embodiment 3

[0067] Add 1500g methanol, 250g tiglic aldehyde, 1.25g ZrCl in the 5L reactor 4 , stirred, heated to 65°C, and refluxed for 2h. After the reaction was completed, it was cooled to room temperature. After the reaction solution was adsorbed by the basic resin to remove the catalyst, the methanol was rectified to obtain the acetal (I) with a yield of 97%.

[0068] Add 1300g of tetrahydrofuran, 260g of acetal (I), 14.8g of copper trifluoromethanesulfonate, and 28.4g of terpyridine into a 5L three-necked flask. Stir, cool to 10°C, add dropwise 792g of tert-butyl peroxyacetate solution, and control the reaction temperature to 10°C. After the dropwise addition was completed, the reaction was continued at 10°C for 2h. After the reaction was completed, samples were taken for gas phase analysis, and the yield was calculated to be 90% according to the analysis results. The acetal ester (II) was obtained by rectification and separation with a purity of >99%.

[0069] Add 1150g of wate...

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Abstract

The invention provides a novel method for preparing 4-acetoxy-2-methyl-2-butenal. The method comprises the following steps: 1, performing a reaction on dimethylacrylic aldehyde and methanol to produceacetal (I); 2, performing a reaction on the acetal (I) and tert-butyl peroxyacetate under the catalysis of copper salt to produce acetal ester (II); 3, hydrolyzing the acetal ester (II) under an acidic condition to obtain the 4-acetoxy-2-methyl-2-butenal. By the method, the starting material, namely the dimethylacrylic aldehyde, is cheap and easy to obtain, a process route is short, few three wastes are produced, and a synthesis route is economical and effective.

Description

technical field [0001] The invention belongs to the field of synthesis of chemical intermediates, in particular to a method for preparing 4-acetoxy-2-methyl-2-butenal. Background technique [0002] 4-Acetoxy-2-methyl-2-butenal (commonly known as "five-carbon aldehyde") is an important intermediate in the synthesis of vitamin A. Due to the importance of 4-acetoxy-2-methyl-2-butenal in the synthesis of vitamin A industry, its synthesis process has long been concerned. [0003] At present, the preparation technology of 4-acetoxy-2-methyl-2-butenal is mainly divided into three categories: 1) using ethylene oxide as a starting material, the main disadvantage is: a large amount of unstable intermediates will be produced , there are higher requirements for the storage of intermediates and the safety of the reaction; 2) using dimethoxyacetone as the starting material, the main disadvantages are: the route is long, the yield is low, and a large amount of by-products are produced; 3)...

Claims

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Application Information

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IPC IPC(8): C07C67/29C07C69/145
Inventor 吕英东胡展梁海涛李少臣李盼程晓波张涛黎源
Owner WANHUA CHEM GRP CO LTD
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