| 摘要 |
In a process for the preparation of acrylonitrile and methacrylonitrile by the oxidation of propylene or isobutylene with oxygen or gases containing oxygen in the presence of ammonia at an elevated temperature, a tin salt of a boromolybdate heteropoly acid on a carrier is used as a catalyst. The weight ratio of stannic oxide to molybdenum oxide is from 10:1 to 1:10, and of boron oxide to molybdenum oxide is from 1:5 to 1:20. and the preferred carrier is silica gel. The catalyst may be prepared by impregnating the carrier with solutions of tin, boron and molybdenum salts, or by coprecipitation of silica gel and tin, boron, molybdate, followed by drying, and the use of a fluidized bed method is preferred.ALSO:Aminoxidation catalyst comprise tin salts of a boromolybdate heteropoly acid supported on a carrier. The weight ratio of stannic oxide to molybdenum oxide is from 10:1 to 1:10, and of boron oxide to molybdenum oxide is from 1:2 to 1:50 and silica gel is preferred as the carrier. The carrier may be impregnated with suitable solutions of tin, boron, molybdenum salts and dyed, silica-gel may be co-precipitated with tin boron molybdate, or the tin salt of boromolybdic acid may be applied in molten form preferably in the presence of a flux e.g. urea or oxalic acid. The particle size is determined by spraying, extrusion or by grinding. In examples of catalyst preparation, boric acid is added to ammonium molybdate solution followed by stannous chloride solution, the solution made alkaline with ammonia, and silica gel kneaded is followed by dying and annealing; ammonium molybdate and boric acid solution is stirred into silica sol and during heating and mixing an acetic acid solution of stannous oxide is flowed in, the mixture is evaporated and calcined. |
