Catalyst for synthesizing 2-cyano pyrazine from 2-methy/pyrazine and synthesizing method

Abstract

The catalyst is VMoOP system carried catalyst prepared via soaking process. The catalyst features the carrier alumina, silica gel and silicon carbide and active component V / P / Mo in the molecular ratio of 1 to 1-6 to 0.01-1. When the catalyst is used in synthesizing 2-cyanopyrazine and the user amount of catalyst is 40 g, the introduced amount of 2-methylpyrazine 0.05-2 ml / min, that of ammonia is 100-200 ml / min and that of air is 1000-2000 ml / min; the material feeding molar proportion among 2-methylpyrazine, ammonia and air is 1 to 8-20 to 10-90. The present invention has the advantages of high catalyst activity, long service life, no need of activation period, simple synthesis process, high material conversion rate and high product quality.

Description

technical field [0001] The invention relates to a catalyst used for synthesizing 2-cyanopyrazine from 2-methylpyrazine through gas-phase catalytic ammoxidation and a synthesis method of 2-cyanopyrazine. It belongs to the preparation technology of 2-cyanopyrazine. Background technique [0002] 2-cyanopyrazine is an important organic chemical raw material and pharmaceutical intermediate. It is widely used in spices, medicine and other fields. Especially in the pharmaceutical industry, the anti-tuberculosis drug pyrazinamide can be prepared after hydrolysis of 2-cyanopyrazine, which is a new route for the preparation of pyrazinamide proposed abroad in the 1980s. Previously, pyrazinamide was obtained by oxidation of benzopyrazine to pyrazine 2,3-dicarboxylic acid through potassium permanganate, alcoholysis and decarboxylation to obtain ethyl pyrazinecarboxylate, and finally ammonia solution. This method has a long process route and requires huge equip...

AI Technical Summary

Problems solved by technology

[0004] Among the above five routes, the raw material cyanoethylenediamine of the first route is difficult to prepare, and its use to prepare 2-cyanopyrazine has only been seen in early reports

The second route raw material pyrazine carboxylic acid is prepared by oxidizing benzopyrazine to 2,3-dicarboxylic acid through decarboxylation, and its separation and purification are difficult (Hall, Spoerri.J.Am.chem.Soc.1940 , 62, 664)

The third synthetic route raw material pyrazinamide is expensive

(5) Sb-V-Mn system Sb, V, Mn supported on α-Al 2 o 3 Above as catalyzer, although there is only 75% selectivity of the conversion rate greater than 90%, total yield is less than 70% (Forni, Lucio Ammoxidation of 2-methylpyrazine over oxide catalysts.Appl.Catal.1986,20(1-2 ), 219-30)