Method for preparing high-purity acetonitrile from acetic acid and ammonia by two steps

Abstract

The invention discloses a method for preparing high-purity acetonitrile from acetic acid and ammonia by two steps, which comprises the following steps of: (1) neutralizing acetic acid and ammonia to generate ammonium acetate; (2) mixing aqueous solution of ammonium acetate and gaseous ammonia, preheating, and making the mixture enter a fixed bed reactor filled with a catalyst aluminium oxide for reaction to generate acetonitrile-containing mixed gas; and (3) continuously refining the mixed gas to obtain the acetonitrile. The 70 to 80 weight percent acetic acid is taken as a raw material, and the produced acetonitrile product has the advantages of less varieties and low content of impurities, high purity of over 99.9 percent, simple separation process, shorter flow, low energy consumption only about 40 percent of that of a byproduct method in unit product, and lower cost. The separation process is a physical separation method, and avoids generating a great amount of wastewater and waste gas in the chemical treatment process of the byproduct method. Meanwhile, a synthesis method is adopted, so the limitation that the yield is limited by a main product can be radically eliminated.

Description

Technical field

[0001] The invention relates to a method for preparing acetonitrile using acetic acid and ammonia as starting materials. Background technique

[0002] Acetonitrile is an important fine chemical intermediate product and chemical solvent. It is an intermediate for the synthesis of medicines and fragrances, such as the active medium solvent for the synthesis of vitamin B1, vitamin A, cortisone and amino acids, carbon amine drugs and their intermediates. Intermediate solvent can replace chlorinated solvent; it is the raw material for the manufacture of triazine nitrogen fertilizer synergist; used as the denaturant of acetic acid; in organic synthesis, it is used to prepare 2-methylpyridine, triazine and ethylamine , Dipropionitrile, imidazole, propylene diacetonitrile, etc. Acetonitrile can be used as an extractant for butadiene and isoprene, a spinning flux for synthetic fibers, and a solvent for special coatings such as vinyl coatings; used in the petroleum industr...