Method for reducing pyridine ring to piperidine in 2-methylpyridine-4-carboxylic acid

A technology for picoline and pyridine rings, applied in the field of reduction of pyridine rings to piperidine, can solve the problems of complex process, expensive production raw materials, low output and the like, and achieve the effects of simple process, short reaction time and fast reaction

CN104945308BActive Publication Date: 2018-11-27WUHAN KONBERD BIOTECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-11-27

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Abstract

The invention discloses a method for reducing a pyridine ring to piperidine in 2-picoline-4-formic acid. The method comprises the step one of preparation of 2-picoline-4-ethyl formate, wherein the initiator 2-picoline-4-formic acid is dissolved into ethyl alcohol solvent, thionyl chloride is dropped into the mixture to carry out esterification reaction to obtain esterification product mixing liquid, and after-treatment is carried out on the esterification product mixing liquid to obtain the 2-picoline-4-ethyl formate; the step two of reduction reaction, wherein the 2-picoline-4-ethyl formate generated through the reaction in the former step is pressurized under the effect of a catalyst, hydrogen is introduced into the 2-picoline-4-ethyl formate to carry out reduction reaction to obtain a reduction product mixing liquid, the addition quantity of the catalyst is 10%-20% of the content of the initiator, and the catalyst is a mixture of palladium carbon and rhodium carbon; the step three of after-treatment, wherein the reaction product mixing liquid reacted in the step two is treated to obtain a 2-picoline-4-ethyl formate product. The new method for producing the 2-picoline-4-ethyl formate has the advantages of being high in efficiency, high in reaction speed and simple in process.
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Description

technical field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for reducing a pyridine ring in 2-picoline-4-carboxylic acid to piperidine. Background technique

[0002] Piperidine is an important chemical raw material. The common synthesis method of piperidine is to add pyridine and nickel catalyst into an autoclave, and when it is heated to 50°C, hydrogen gas is introduced, and the hydrogen is continuously heated until 200°C, and the hydrogen pressure reaches nearly 7MPa. Until hydrogen is absorbed again, the reaction solution is filtered, the filtrate is fractionated, and the distillate at 102-108°C is collected to obtain piperidine. Another preparation method is to heat pyridine in absolute ethanol, put in sodium metal, and after the reaction, distill with water steam to distill piperidine and ethanol, neutralize with hydrochloric acid and distill off ethanol to obtain piperidine hydrochloride , treated wit...

Examples

Embodiment Construction

[0018] The following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0019] The reaction formula of reducing the pyridine ring into piperidine in 2-picoline-4-carboxylic acid is:

[0020]

[0021] A kind of method that pyridine ring is reduced into piperidine in 2-picoline-4-carboxylic acid, concrete steps are as follows,

[0022] The first step prepares ethyl 2-methylpyridine-4-carboxylate, the preparation method is as follows,

[0023] First, dissolve 90-100 g of 2-picoline-4-carboxylic acid in 700 ml of ethanol solvent, stir evenly, place at 0°C, add 106 g of thionyl chloride dropwise, rise to...