METHOD FOR REUSING ALKALI

摘要

PROBLEM TO BE SOLVED: To enable to reuse an aqueous alkaline solution and reduce its used amount by removing hydrogen cyanide from acetonitrile produced by ammoxidation of an olefin as a by-product and successively dehydrating it by using a specific aqueous alkali solution. SOLUTION: Hydrogen cyanide and acrylonitrile are removed from acetonitrile produced by ammoxidation of an olefin as a by-product and acetonitrile is dehydrated by using an aqueous alkaline solution preferably having <=40 wt.% concentration of an alkali such as sodium hydroxide or the like. Here, as the aqueous alkaline solution, (A) a recovered aqueous alkaline solution obtained by heating and concentrating the aqueous alkaline soluticn used for dehydrating acetonitrile produced as a by-product and/or (B) a recovered aqueous alkaline solution obtained by heating and concentrating the aqueous alkaline solution used for removing hydrogen cyanide and acrylonitrile included in the acetonitrile produced as a by-product.