Preparation method of cyclopentanecarboxylic acid

Abstract

The invention discloses a preparation method of cyclopentanecarboxylic acid. The method comprises the following steps: S1, mixing diethyl malonate with an alcohol solvent, sequentially adding sodium ethoxide and 1,4-dibromobutane, generating diethyl cycloglutarate under the action of alkaline conditions, hydrolyzing the diethyl cycloglutarate under an acidic condition, and adding alkane and esters to generate a cycloglutaric acid intermediate; and S2, adding the cycloglutaric acid intermediate obtained in the step S1 into a water-insoluble ether organic solvent with a high boiling point in batches under a high-temperature condition, separating a water phase under an alkaline condition, washing the water phase with the water-insoluble organic solvent, adding dichloromethane under an acidic condition, separating an organic phase, and concentrating the organic phase to obtain cyclopentanecarboxylic acid. According to the method, the production difficulty of cyclopentanecarboxylic acid can be reduced, the purity of cyclopentanecarboxylic acid is improved, and industrial production is easy to realize.

Description

Technical field [0001] The present invention relates to the field of production of chemical raw materials, particularly to a method for the preparation of carboxylic acid cyclopentyl. Background technique [0002] Cyclopentyl acid, pentanoic acid, also known as ring, is an important organic intermediates used in research and development of new drugs and special intermediate, downstream products include cyclopentyl stearyl acid and the like. [0003] Currently, synthetic methods mainly make the cyclopentyl acid diethyl malonate and sodium alkoxide and then 1,4-dibromobutane the reaction the reaction, after purification, addition of basic hydrolysis, acidification and then heated 24-48h, cyclopentyl generated formic acid, will produce large amounts during the production of acid and base and the reaction time longer and more cumbersome process, and polluting the environment. In addition, China patent document discloses a method for preparing cyclopentanone acid (Application Publicat...

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Problems solved by technology

[0003] At present, the synthesis method of cyclopentacarboxylic acid is mainly to react diethyl malonate with sodium alkoxide and then react with 1,4-dibromobutane, after purification, add alkali for hydrolysis, then acidify and heat for 24-48h to generate cyclopentane Formic acid, a large amount of acid and alkali will be produced during production, and the reaction time is long, the post-treatment is cumbersome, and it has great environmental pollution

In addition, the Chinese patent literature discloses a preparation method of cyclopentacarboxylic acid (application publication number: CN108675925), which utilizes epoxycyclopentane as a starting material to react with carbon dioxide, magnesium powder and TMSCl to generate 2-hydroxycyclopentacarboxylic acid, 2-Hydroxycyclopentacarboxylic acid is obtained under the catalytic hydrogenation of palladium-carbon hydrogen to cyclopentacarboxylic acid. Although the route is relatively novel, the requirements for production equipment are extremely high, which will greatly increase the production cost, which is not conducive to the realization of industrial production.

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