Catalyst and process of oxidative dehydrogenation of propane

A catalyst for oxidative dehydrogenation of propane, wherein the catalyst is prepared by the following steps:

• a) dissolving alkali or alkaline earth metal oxometalate salts of W, V, and Nb in water at a temperature ranging from 40 to 80° C., wherein the molar ratios W:V and V:Nb are from 2 to 8, to obtain an aqueous solution of polyoxometalates wherein the mass ratio of the polyoxometalates to water is between 30% and 40%;
• b) adding to the aqueous solution of polyoxometalates obtained in step (a) an inorganic acid to a pH between 6.5 and 7.5, and heating the aqueous solution of polyoxometalates to temperatures of 150 to 180° C. for a period of time ranging from 3 to 4 hours;
• c) adding, under constant agitation, to the aqueous solution of polyoxometalates of step (b) a saturated solution of an alkali or alkaline earth metal salt, in an amount of 60% to 80% (v/v) of aqueous solution of polyoxometalates relative to the saturated solution of an alkali or alkaline earth metal salt, to obtain a precipitate of mixed polyoxometalate salts of W, V, and Nb;
• d) filtering and drying the precipitate of mixed polyoxometalate salts obtained in step (c) at a temperature ranging from 25 to 50° C. to obtain a dried mixture of polyoxometalate salts;
• and
• e) promoting calcination of the dried mixture of polyoxometalate salts obtained in step (d) under air flow at temperatures of from 350 to 550° C. for a period of time from 3 to 5 hours to obtain mixed oxide catalysts of W, V, and Nb having structures of tungsten bronzes.