Synthesis method of 2-methyl-2-pentenoic acid

A synthesis method and technology of pentenoic acid, which are applied to the preparation of carbon-based compounds, chemical instruments and methods, and the preparation of carboxylic acid nitriles, can solve the problems of high raw material prices, easy deep oxidation, and difficult separation and purification, and achieve good aroma of the product , Simple operation, good process stability

Active Publication Date: 2014-01-29
SHANGHAI WANXIANG FLAVORS & FRAGRANCES
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  • Abstract
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Problems solved by technology

[0008] The main defect of the synthesis method (1) and (2) is that the process operation is relatively complicated, and the price of the raw material is high and not easy to obtain, which is not suitable for industrial production; Purification is difficult, which affects the aroma quality of the final product; synthetic method (4) is currently the main production method used in industry, but the oxidant price is relatively high, resulting in relatively high production costs, and it is easy to be deeply oxidized, thereby affecting the aroma of the final product

Method used

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  • Synthesis method of 2-methyl-2-pentenoic acid
  • Synthesis method of 2-methyl-2-pentenoic acid

Examples

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Embodiment 1

[0024] The synthesis of embodiment 1 2-methyl-2-pentenal

[0025] Add 10 grams of ammonium acetate and 30 grams of cyclohexane into a 500ml three-necked reaction flask, raise the temperature to 40 degrees and start to add 300 grams of n-propionaldehyde dropwise. The dropping time is 3 hours. , then reclaim solvent cyclohexane, distill to obtain 202 grams of 2-methyl-2-pentenal, yield 80%;

Embodiment 2

[0026] The synthesis of embodiment 2 2-methyl-2-pentenal

[0027] Add 10 grams of pyridine and 30 grams of cyclohexane into a 500ml three-necked reaction flask, raise the temperature to 40 degrees, and start to add 300 grams of n-propanal dropwise. The addition time is 3 hours. Then reclaim solvent cyclohexane, distill to obtain 215 grams of 2-methyl-2-pentenal, yield 85%;

Embodiment 3

[0028] Example 3 Synthesis of 2-methyl-2-pentenaldoxime

[0029] Add 100 grams of 2-methyl-2-pentenal, 130 grams of hydroxylamine sulfate and 300 grams of water into a 1000ml three-necked reaction flask, control the temperature at 10-15 degrees and start adding 120 grams of 50% sodium hydroxide solution dropwise, drop Add for about 3-5 hours, keep the temperature for 30 minutes after the dropwise addition, and then add 100 grams of mesitylene for extraction to obtain 208 grams of 2-methyl-2-pentenal mesitylene solution, with a yield of 93%;

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Abstract

The invention discloses a synthesis method of a 2-methyl-2-pentenoic acid. The method comprises the following steps: by taking n-propanal as a raw material, synthesizing 2-methyl-2-pentenal by aldehyde-aldehyde condensation; generating 2-methyl-2-pentene aldehyde oxime by the effects of the 2-methyl-2-pentenal and hydroxylamine; dewatering and synthesizing 2-methyl-2-allyl acetonitrile by using the 2-methyl-2-pentene aldehyde oxime under the effect of acetic anhydride; hydrolyzing the 2-methyl-2-allyl acetonitrile into the 2-methyl-2-pentenoic acid under the effect of a sulfuric acid. The reaction formula of the 2-methyl-2-pentenoic acid is shown in the specification. Compared with the prior art, the technology disclosed by the invention has main advantages that the synthesis method is available in synthetic materials, simple to operate, good in process stability, and good in fragrance of synthetic product.

Description

technical field [0001] The invention relates to a synthesis method of 2-methyl-2-pentenoic acid, which belongs to the technical field of organic synthesis. Background technique [0002] 2-Methyl-2-pentenoic acid, also known as strawberry acid, is a very useful flavoring, with the aroma of fresh strawberries, and can be blended with a variety of flavors, such as candy flavors blended with geraniol, Has an excellent strawberry aroma. [0003] The 2-methyl-2-pentenoic acid synthetic method of current bibliography mainly is divided into following several kinds: [0004] (1) Using 2-pentanone as raw material, it is synthesized by addition, hydrolysis and decarboxylation ("Practical Synthetic Perfume", Ding Desheng, Shanghai Science and Technology Press, 1991, 242-245); [0005] (2) Using 2-methylpentanoic acid as raw material, it is synthesized by bromination, esterification, elimination, saponification and hydrolysis ("Practical Synthetic Perfume", Ding Desheng, Shanghai Scien...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/03C07C51/08
CPCC07C45/74C07C51/08C07C249/08C07C253/00C07C57/03C07C255/07C07C251/40C07C47/21
Inventor 宋芬陈万锁
Owner SHANGHAI WANXIANG FLAVORS & FRAGRANCES
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