Abstract: Removing oligomers (short chain polymers of from two to seven atoms in the chain) from olefin monomer vapor recovered for recycle from the reaction mass resulting from the catalytic polymerization of liquid olefinic monomers by flowing such recovered vapor through a mass transfer plate tower upwardly through openings in the plates of said tower and in the form of bubbles through layers of liquid oligomer reflux maintained on said plates by weirs and downcomers by means of which said reflux is flowed from each plate downwardly to the plate below it and, as a layer, along the top of the plate and thence downwardly to the next lower plate, condensing in a reflux condenser the vapor from the top of said tower, removing olefin monomer from said condenser as a vapor and refluxing condensed liquid oligomers back to the top of said tower. Preferably the tower is a valve tray tower and the plates are valve trays.

Abstract: A method of producing unsaturated nitriles by reaction of an unsaturated hydrocarbon with ammonia and oxygen in a reactor having a fluidized catalyst bed comprising a regeneration zone and a reaction zone, characterized by introducing between about 3 percent and about 90 percent of the total amount of ammonia supplied to the reaction to the regeneration zone together with oxygen and introducing the remainder of the ammonia to the reaction zone together with the hydrocarbon feed.