| abstract |
The oxidation catalysts contain oxygen, molybdenum, phosphorus, cobalt, nickel and bismuth and are characterized inthatthey also contain tellurium and, optionally, one or more of Fe, Sb, Cs, Zr, Cu, B. Al, K, La, Pr, Ru, V, W and Y, wherein the above listed elements are present in relative atomic proportions represented by the empirical formula MoaPbFecCod NieBifTeg Sb h CsiZrjXkOx wherein, when a is 12, b is a number from 1.5 to 2.5; c is a numberfrom 0 to 7; d is a number from 1 to 7; e is a number from 1 to 6; f is a number from 0.5 to 1.5; g is a number from 0.5 to 2; h is a number from 0 to 1; i is a number from 0 to 1; j is a number from 0 to 2; k is a number from 0 to 2.0; x is a value determined according to the state of oxidation of the catalyst and X is one or more elements selected from Cu, B. Al, K, La, Pr, Ru, V, W and Y. The catalysts are used for the preparation of methacrolein by the vapour phase catalytic oxidation of a feed containing molecular oxygen and isobutylene or other compound yielding methacrolein under the reaction conditions employed, e.g. tert-butanol, tert-butyl acetate ortert-butyl methyl ether. |