Catalyst for preparing methacrylic acid

Abstract

This invention relates to a novel catalyst for preparing methacrylic acid by gas phase oxidation of methacrolein obtained by gas phase catalytic oxidation of isobutylene or t-butanol. The catalyst is represented by the formula: P.sub.a Mo.sub.11 V.sub.b Du.sub.c X.sub.d Q.sub.e Z.sub.f O.sub.g wherein X is at least one of potassium, rubium, cessium, and thallium; Z is at least one of lead, antimony, chromium, iron, bismuth, cerium, and zinc; Q is at least one of organic quaternary ammonium cations consisting of ##STR1## in which R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 substituted alkyl having functional groups; a is a number from 0.8 to 1.6; b is a number from 0.6 to 2; c is a number from 0.1 to 0.8; d is a number from 0.7 to 2.2; e is a number from 0.01 to 0.1; f is a number from 0 to 0.5; and g is a number of oxygens required to satisfy the valence requirements of the other elements present.

Dependencies are inferred from the claim text.