Synthesis of Isobutyronitrile from Isobutyraldehyde and Ammonia

Abstract

The vapour phase reaction of isobutyraldehyde with ammonia in the presence of alumina modified with alkali at 350∼500°C has been studied by a flow method.
Catalytic activity of NaOH-Al₂O₃ increases with the increasing amount of NaOH up to 3.0m mol NaOH/g Al₂O₃ and decreases thereafter. In the optimum condition, in which ammonia and isobutyraldehyde are reacted at the mole ratio of 2:1 in the presence of 2-3m mol NaOH/g Al₂O₃ at 410∼430°C for about 10 seconds of contact time, 93∼96% of isobutyronitrile, 1∼2% of methacrylonitrile and 1∼2% of by-products (mainly heteroaromatic compounds) are formed. The catalyst can be easily regenerated by heating with air. The activity of modifiers of alumina is in the order of NaCl<LiOH≤none<Ca(OH)₂<NaOH<KOH>CsOH>RbOH>none.