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

A synthesis method, technology of pentenoic acid, applied in the direction of carbon monoxide reaction to prepare carboxylic acid, organic chemical method, chemical instrument and method, etc., can solve the problems of insignificant industrial application benefits, many reaction steps, low yield, etc., and achieve atomic Good utilization rate, low production cost, and low equipment requirements

Active Publication Date: 2021-09-03
SHANDONG NHU PHARMA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 2. Using 2-methylpentanoic acid as the starting material, strawberry acid was synthesized through 5 steps of α-bromo, esterification, hydrolysis dehydration, saponification and acidification. This method has many reaction steps and low yield. Industrial Application benefits are not obvious
[0010] 4. Propionaldehyde and butanone are condensed under the catalysis of sulfuric acid to obtain 3-methyl-3-hexen-2-one; afterward, strawberry acid is obtained through haloform reaction, and the yield of this method is not high
In these patents, the reaction adopts palladium salt as a catalyst, but what is mainly obtained is a mixture of 2-, 3- and 4-pentenoic acid, and the selectivity is poor

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-25

[0063] Add catalyst 1 (rhodium salt and ligand) into the autoclave, add a solvent and stir to coordinate and dissolve the rhodium salt and ligand, then add piperylene and water. Close the reaction kettle, first replace the air in the kettle with nitrogen three times, then replace it with carbon monoxide three times, raise the temperature to the set temperature, and use carbon monoxide to replenish the pressure to the set pressure. The reaction is started, and the end point of the reaction is detected by the gas phase, and then the reaction liquid is moved to a rectification tower for vacuum distillation and separation to obtain the cis and trans isomers of 2-methyl-3-pentenoic acid. The specific experimental results are shown in Table 1 below.

[0064] Table 1 Experimental results of step (1)

[0065]

[0066]

[0067] According to the results in the above table, we can draw the following conclusions: comparative examples 1-4, the rhodium salt is preferably Rh 2 (CO) ...

Embodiment 26-36

[0069] Add a certain amount of catalyst 2 (zinc chloride / acetic acid solution) to the cis-trans isomers of 2-methyl-3-pentenoic acid obtained in step (1), and heat up to a set temperature to carry out isomerization reaction. The end point of the reaction is detected by the gas phase. After the reaction is completed, the reaction is washed twice with distilled water, and the upper oil phase is obtained by liquid separation. Then the reaction liquid is moved to a rectification tower for vacuum distillation and separation to obtain trans-strastracaric acid. The specific experimental results are shown in Table 2 below.

[0070] Table 2 Experimental results of step (2)

[0071]

[0072] According to the result in the above table, we can draw the following conclusions: the charging capacity of zinc chloride / acetic acid catalyst is preferably 8-13% (with the mass ratio of cis and trans isomers), and the chlorination in zinc chloride / acetic acid solution The mass concentration of ...

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Abstract

The invention adopts a Reppe synthesis method to prepare 2-methyl-2-pentenoic acid. The method comprises the following steps: firstly, by taking m-pentadiene, carbon monoxide and water as raw materials, and taking precious metal rhodium salt and an organic phosphine ligand as catalysts, preparing a cis-trans isomeric intermediate of 2-methyl-3-pentenoic acid, and then carrying out isomerization reaction on the obtained intermediate product to generate trans-2-methyl-2-pentenoic acid, namely trans strawberry acid.

Description

technical field [0001] The invention relates to a reaction for synthesizing an acid by using olefin as a raw material, in particular to a synthesis method of trans 2-methyl-2-pentenoic acid, which belongs to the fields of fine chemicals and flavors and fragrances. Background technique [0002] Strawberry acid, also known as 2-methyl-2-pentenoic acid, naturally exists in strawberries, mostly in the trans form. It is a food flavoring that is allowed to be used in the national standard "GB 2760-1996". It not only has the aroma of fresh strawberries, but also With a sweet berry-like aroma and acidity, the taste is full-bodied, rich and persistent. It is mainly used to prepare edible strawberry, hawthorn, cheese, raspberry and tropical fruit flavors; it can also be used to make citrus-flavored food flavors, which can be directly used in beverage and food processing. In addition to being used in food flavors, strawberry acid is also used in daily chemical flavor formulations. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/14C07C51/353C07C57/03B01J31/22B01J31/20B01J31/18B01J31/24
CPCC07C51/14C07C51/353B01J31/2213B01J31/20B01J31/1845B01J31/2414C07B2200/09B01J2531/822B01J2531/0238B01J2531/0288B01J2231/321C07C57/03
Inventor 李守垒马啸于明董士琪王勇郝广果尹婵
Owner SHANDONG NHU PHARMA
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