Operation of heads column

A process for the recovery of acrylonitrile, methacrylonitrile or hydrogen cyanide obtained from the reactor effluent of an ammoxidation reaction of propane, propylene or isobutylene comprising passing said reactor effluent through an absorber column, a recovery column and a heads column comprising a feed tray wherein the improvement comprises operating said heads column in a manner which inhibits the formation of an aqueous phase above the feed tray of said heads column;

• wherein said operating manner of said heads column comprises feeding more hydrogen cyanide to said heads column to achieve conditions equivalent to higher reflux ratio and wherein said feeding is selected from the group consisting of (a) recycling purified HCN to the heads column and (b) operating the ammoxidation reactor in a manner to produce said reactor effluent with high concentration of HCN.