Supported catalyst, process for its preparation and its application in the preparation of styrene

摘要

The invention relates to a carrier-supported catalyst comprising oxides of cobalt and phosphorus and at least one of the oxides of molybdenum and potassium in the atomic ratio of Co1P1-2Mo0-0.05K0-0.5 on a porous carrier material, and to a process for making it. To this end, the process provides (a) for a dry porous carrier material to be saturated with water up to 40 to 80% of its predetermined saturation value; (b) for the carrier material treated as under (a) to be impregnated either at least once with an aqueous solution of water-soluble compounds of cobalt and phosphorus, molybdenum and/or potassium, or repeatedly and successively, each impregnation being interrupted by an intermediary drying period as specified under (c), with an aqueous solution of a water-soluble compound of merely one of the elements aforesaid, the aqueous solution being used in either case in a quantity which is at most necessary for complete saturation; (c) for the carrier material to be dried after each impregnation over a period of 2 to 20 hours at 350 to 500 K; and (d) for the carrier material treated as described under (a) through (c) to be sintered over a period of 0.5 to 4 hours at 550 to 1000 K, in a stream of air. The carrier-supported catalyst finds use in the production of styrene by subjecting ethylbenzene to oxidative dehydrogenation with molecular oxygen in gas phase.