Multimetal oxide composition, useful as oxidation catalyst, especially for gas phase production of (meth)acrylic acid, is based on crystallites of constant composition

摘要

Multimetal oxide composition (I) comprises: (i) a multimetal oxide (II) of molybdenum with vanadium, niobium, tantalum, tungsten and/or rhenium and boron, silicon, phosphorus, germanium, arsenic and/or antimony and optionally other metal(s) or (ii) a mixture of (II) and another multimetal oxide (III), in which (I) consists of crystallites of constant composition. Multimetal oxide composition is of formula (I); (A)p(B)q (I) Mo12X1aX2bX3cX4dX5eOx (II) MofX6gX7hOy (III) A = a multimetal oxide of formula (II); B = a multimetal oxide of formula (III); X1 = hydrogen, up to 97 mole-% of which may be replaced by ammonium, potassium, rubidium and/or cesium; X2 = vanadium, niobium (Nb), tantalum (Ta), tungsten and/or rhenium; X3 = boron, silicon, phosphorus, germanium, arsenic and/or antimony (Sb); X4 = chromium, manganese, iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), magnesium (Mg), calcium (Ca), strontium (Sr) and/or barium (Ba); X5 = sulfur; X6 = Cu, Fe, Co, Ni, Zn, cadmium, Mn, Mg, Ca, Sr and/or Ba; X7 = Nb, Ta and/or Sb; a = 1-3; b = 0.1-2; c = 0-5; d, e = 0-1; f = 0-2; g = 0.5-1.5; h = 2-4; x, y = values depending on the valency and frequency ox elements other than oxygen; p = 1; and q = 0; or p, q not = 0 and p/q = (160-1):1. The standard deviation of the stoichiometric coefficient a of the variable X1 of individual crystallites of component A is less than 0.15, especially less than 0.10. Independent claims are also included for: (a) methods of preparing the multimetal oxide (I); (b) the apparatus used in preparation.