Methods for preparing catalysts for methacrolein oxidation
AssigneeSaudi Basic Industries Corporation
InventorsScott A. Stevenson, Wugeng Liang, James W. Kauffman, Lixia Cai, Angie McGuffey, Joseph R. Linzer
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Abstract
Methods of making catalysts for oxidation of unsaturated and/or saturated aldehyde to unsaturated acids is disclosed where the catalyst including at least molybdenum (Mo) and phosphorus (P), where the catalyst has a pore size distribution including at least 50% medium pores and if bismuth is present, a nitric acid to molybdenum mole ratio of at least 0.5:1 or at least 6.0:1 moles of HNO3 per mole of Mo12.
Claims41
A method for preparing an heteropolyacid catalyst for converting aldehydes to unsaturated acids comprising the steps of:
- forming a pre-catalyst composition comprising:
- molybdenum and phosphorus in a 12:a mole ratio, and
- an effective amount of an ammonium-containing compound,
- where a is a number having a value between about 0.5 and about 3.5,
- evaporating the pre-catalyst composition to form a dried catalyst composition, and
- calcining the dried catalyst composition to form the heteropolyacid catalyst,
- where the effective amount of the ammonium-containing compound is sufficient to produce a pore size distribution comprising at least 50% medium pores in the catalyst.
A method for preparing an heteropolyacid catalyst for converting aldehydes to unsaturated acids comprising the steps of:
- forming a pre-catalyst composition comprising:
- molybdenum and phosphorus in a 12:a mole ratio, where a is a number having a value between about 0.5 and about 3.5 and
- an amount of an ammonium-containing compound sufficient to produce a Mo:NH4 mole ratio between about 0.5 to about 20.0,
- evaporating the pre-catalyst composition to form a dried catalyst composition, and
- calcining the dried catalyst composition to form the heteropolyacid catalyst.
In a process for producing a catalyst having a composition comprising molybdenum and phosphorus in a 12:a mole ratio usable to produce methacrylic acid by the gas-phase catalytic oxidation of methacrolein with molecular oxygen, where a is a number having a value between about 0.5 and about 3.5, an improvement comprising adding at least 6.0 mole of nitric acid based on 12 moles of molybdenum to the catalyst components.
Dependencies are inferred from the claim text.