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Method for preparing 3-methyl-2-butenoic acid

The technology of crotonic acid and methyl group is applied in the field of preparation of spice, medicine and pesticide intermediate 3-methyl-2-butenoic acid, and can solve the problems of large environmental pollution, high equipment requirements, production of sulfuric acid waste water and the like, To achieve the effects of environmental friendliness, high reaction yield and less side reactions

Active Publication Date: 2009-03-25
ZHEJIANG NHU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method needs to react under pressure, which requires high equipment; and sulfuric acid waste water is generated during the hydrolysis process, which causes great environmental pollution.

Method used

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  • Method for preparing 3-methyl-2-butenoic acid
  • Method for preparing 3-methyl-2-butenoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Embodiment 1 is the preparation of 3-methyl-2-butenal, and Embodiment 2-6 is the preparation of 3-methyl-2-butenoic acid.

[0019] Example 1

[0020] In the 500ml there-necked flask with mechanical stirring, thermometer, reflux condenser, drop into 95% 2-methyl-3-butyn-2-alcohol (water content 5%) 88.5g (1.0mol), liquid paraffin 100g, 6.1g (0.05mol) of benzoic acid, 2.6g (0.01mol) of titanyl acetylacetonate, 1.4g (0.01mol) of cuprous bromide, heated to 110-120°C for 3 hours under stirring, and cooled to room temperature after the reaction was completed. After filtration, the filtrate was rectified under reduced pressure to obtain 76 g of 3-methyl-2-butenal, with a yield of 90.5%.

Embodiment 2

[0022] In the 1000ml four-necked bottle with mechanical stirring, thermometer, vent pipe, condenser, drop into 420g (5.0mol) 3-methyl-2-butenal, drop into manganese acetate 0.5g, start stirring, keep stirring speed as 800-1000 rpm, under normal pressure, feed air from below the liquid surface at a rate of 1 liter / min, keep the reaction temperature at 30-40°C, feed the air for 24 hours, stop the air flow, and cool to 0°C , precipitated 3-methyl-2-butenoic acid solid, filtered, and dried to obtain 150g of 3-methyl-2-butenoic acid; 265g of the filtrate was recovered, and the filtrate contained 55g of 3-methyl-2-butenoic acid , 210 g of 3-methyl-2-butenal, and the total yield of 3-methyl-2-butenoic acid was 82%.

Embodiment 3

[0024] Put 420g (5.0mol) of 3-methyl-2-butenal in a 1000ml four-necked bottle equipped with a mechanical stirrer, a thermometer, a vent tube, and a condenser, and put in 0.5g of cuprous chloride, start stirring, and keep stirring The speed is 800-1000 rpm, and the air is passed under the liquid surface at a rate of 1 liter / min under normal pressure, and the reaction temperature is kept at 60-70°C, and the air is fed for 8 hours, and the air is stopped while it is hot. Filtrate, cool to 0°C, precipitate 3-methyl-2-butenoic acid solid, filter and dry to obtain 160g of 3-methyl-2-butenoic acid; recover 265g of filtrate, which contains 3-methyl-2-butenoic acid 35 g of 2-butenoic acid and 220 g of 3-methyl-2-butenal, the total yield of 3-methyl-2-butenoic acid was 82%.

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Abstract

The invention discloses a preparation method of 3-methyl-2-butenoic acid. The existing method has great amount of three wastes which pollute the environment heavily. The method is characterized in that: 2-methyl-3-butyne-2-alcohol is adopted as a raw material; 3-methyl-2-butenoic aldehyde is obtained by the complex system of acetylacetone titania-copper bromide-benzoic acid through catalytic reforming, and finally the 3-methyl-2-butenoic acid is obtained by oxidizing 3-methyl-2-butenoic aldehyde; and an oxidizer adopted is air or oxygen or the mixture of air and oxygen, wherein, the preference is air. The oxidizer adopted by the method is safe, avirulent and easy to be controlled, and has low cost; in addition, the reaction yield is high and the product purity is high on the premise of ensuring no pollution to the environment.

Description

technical field [0001] The invention relates to a preparation method of spice, medicine and pesticide intermediate 3-methyl-2-butenoic acid. Background technique [0002] 3-Methyl-2-butenoic acid, also known as isopentenic acid and seneconic acid, is used as a fragrance, medicine and pesticide intermediate. 3-methyl-2-butene acid derivatives 3-methyl-2-butene methyl ester and 3-methyl-2-butene ethyl ester are used as perfumes. 3-Methyl-2-butenoic acid can be used in the synthesis of pyrethroid pesticides and the antifungal drug ciclopirox. Some 3-methyl-2-butenoic acid esters are highly toxic to mosquitoes, gadflies, and lice, but low-toxic to humans and mammals, so some 3-methyl-2-butenoic acid esters are expected to become highly effective pesticides. [0003] The structural formula of 3-methyl-2-butenoic acid is as follows: [0004] [0005] The method of existing synthetic 3-methyl-2-butenoic acid mainly contains following two kinds: [0006] 1. Use acetone as raw...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/03C07C51/235
Inventor 商志才钱洪胜王伟孟建波陈洪光
Owner ZHEJIANG NHU CO LTD
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