FIELD: chemistry.
SUBSTANCE: invention relates to a single-step method for vapour-phase oxidation of an alkane such as propane which leads to production of unsaturated caboxylic acid such as acrylic or methacrylic acid in the presence of a mixed metal oxide catalyst and excess alkane with respect to amount of oxygen. The method of producing unsaturated carboxylic acid involves: (a) reacting alkane and oxygen-containing gas in a reaction zone with a catalyst which contains mixed metal oxide under conditions which enable production of a gaseous product containing unsaturated carboxylic acid, unreacted alkane and an alkene by-product; (b) extraction of unreacted alkane and alkene by-product from the gaseous product; and (c) recycling the mixture of the extracted unreacted alkane and alkene by-product to the reaction zone without separating components; in which the mixed metal oxide consists of material with general formula MoVvAaBbCcOx where Mo is molybdenum, V is vanadium, each of A, B and C represents niobium, antimony, tellurium, silver, tantalum, titanium, aluminium, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, platinum, bismuth, boron, indium, arsenic, germanium, tin, lithium, sodium, potassium, rubidium, caesium, francium, beryllium, magnesium, calcium, stronium, barium, hafnium, lead, phosphorus, promethium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, gold, selenium, palladium, gallium, zinc, praseodymium, rhenium, iridium, neodymium, yttrium, samarium and terbium, v equals 0.1-0.5, a equals 0.01-0.2, b equals 0.0-0.5, c equals 0.0-0.5, value of x is determined by valency of other components, in which alkane is propane or isobutane; where the alkane is in excess relative oxygen and molar ratio alkane: oxygen ranges from 3:1 to 1:1; and in which amount of alkene recycled to the reactor corresponds to the molar ratio alkane: alkene equal to 1:0.03-1:0.1.
EFFECT: improved method.
14 cl, 3 tbl, 1 dwg, 23 ex
