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

摘要

The invention relates to a supported catalyst composed of oxides of chromium and tungsten and at least one of the oxides of molybdenum and potassium in the atomic ratio Cr1W0.1 - 0.5Mo0 - 0.05 K0 - 0.5 on a porous support material and a process for its preparation, wherein a) a dry, porous carrier material is soaked with water until 40 to 80% of the previously determined saturation value is reached; b) the pre-impregnated carrier material, in any order, at least once with an amount of an aqueous solution of water-soluble compounds of chromium and optionally of potassium which is at most sufficient for complete saturation and in succession at least once with an amount which is at most sufficient for complete saturation each of a separately prepared aqueous solution impregnated with a water-soluble compound of tungsten and optionally of molybdenum; c) the carrier material dries for 2 to 20 hours at 350 to 500K after each impregnation and d) finally sinters in the air flow at 550 to 1000 K for 0.5 to 12 hours. The supported catalyst can be used in the reactor (3) for the production of styrene by oxidative dehydrogenation of ethylbenzene with molecular oxygen in the gas phase.