Vanadium catalysts prepared with phosphonates

Claim 1

In a process for preparing a phosphorus-vanadium-oxygen catalyst wherein a pentavalent vanadium compound is contacted with a phosphorus compound under conditions to provide a substantial amount of tetravalent vanadium and to for a phosphorus-vanadium-oxygen precursor, the improvement which comprises contacting the pentavalent vanadium compound with a phosphonate compound selected from the group consisting of: ##STR5## where each X is selected from the group consisting of hydrogen and lower alkyls containing 1 to 4 carbon atoms and M is a member selected from the group consisting of hydrogen and cations; ##STR6## wherein X is a member selected from the group consisting of hydrogen and lower alkyl (1-4 carbon atoms) and Y is a member selected from the group consisting of hydrogen, hydroxyl and lower alkyl (1-4 carbon atoms), and M is a member selected from the group consisting of hydrogen and cations; and ##STR7## wherein each X is selected from the group consisting of hydrogen and lower alkyls containing 1 to 4 carbon atoms; n is either 2 or 3; m is 0 to 12; R 3 is selected from the group consisting of hydrogen, lower alkyl containing 1 to 4 carbon atoms and --CH 2 PO 2 M group; R 1 , R 2 , R 4 and R 5 are from the group of radicals ##STR8## with the proviso that at least two --C(X)(X)PO 3 M 2 groups are present at all times and are either R 1 and R 2 or R 4 and R 5 and that the compound gives a positive result with the vanadium reducing test.