Denka Chemical Corporation

Petro-Tex Chemical Corporation

Scientific Design Company, Inc.

Bruno J Barone

Ralph O Kerr

Gaylon T Click

William G Bowman

An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus, zinc and lithium mixed oxides which comprises adding a molybdenum compound modifier in an amount of from about 0.005 to 0.025/1 Mo/V to the catalyst during the digestion of the reduced vanadium compound by concentrated phosphoric acid. The addition of Mo produces a catalyst which is very stable more active system and longer lived than the unmodified catalyst.

Phosphorous/vanadium oxidation catalyst

An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus, zinc and lithium mixed oxides which comprises adding a molybdenum compound modifier in an amount of from about 0.0005 to 0.025/1 Mo/V to the catalyst during the digestion of the reduced vanadium compound by concentrated phosphoric acid. The addition of Mo produces a catalyst which is very stable more active system and longer lived than the unmodified catalyst.

The useful life of vanadium-phosphorus-oxygen (PVO) catalyst in fixed bed reactors can be substantially extended by treatment with a phosphorus compound followed by steam treatment. The PVO catalysts may be treated with steam after long periods (months) of only phosphorus compound treatment and the benefit of the present invention obtained or the phosphorus and steam treatments may be of only a few hours duration and sequential. In extending the useful life of the PVO catalyst according to the present invention, the temperature profile in the catalyst bed is restored to substantially the same profile as the fresh catalyst.

Process for the production of maleic anhydride

It has been found that phosphoric acid alone and in admixture with phenothiazine and/or methyl-p-benzoquinone reduces residue formed during the fractionation of aqueous crude maleic compositions for the production of maleic anhydride, and in particular, reduces residue due to the presence of small amounts, i.e., less than 10 ppm alkali metal ion. When the alkali metal ion is present at least 9 equivalent acid groups of phosphoric acid per atomic equivalent of alkali metal ion are present.

Maleic anhydride process

Steam regeneration of phosphorus treated vanadium-phosphorus-oxygen

Phosphorus-Vanadium oxidation catalyst prepared as tablets with a hole in the center produce higher yields of maleic anhydride from C.sub.4 's, particularly n-butane than the same catalyst without the hole.

Catalyst structure for the partial oxidation of n-butane to produce

An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus mixed oxides which comprises adding a zinc compound in an amount of from about 0.15 to 0.001/l Zn/V to the catalyst during the digestion of the reduced vanadium component by concentrated phosphoric acid. The addition of zinc produces a catalyst which is more easily activated and which is very stable to heat upset of the reaction system. Small amounts of lithium and silicon compounds also have additional desirable catalytic effects without dimunition of the zinc compound benefit.

Partial oxidation catalyst

The preparation of phosphorus-vanadium oxidation catalyst by the reduction of the valence of vanadium to less than +5 is obtained by employing less than the stoichiometric amount of reducing agent necessary to reduce the valence of the vanadium from +5 to +4, preferably 70 to 98% of the stoichiometric amount of reducing agent can be used.

Catalyst preparative method

A catalyst complex useful for the partial oxidation of alkanes to the corresponding anhydrides, e.g., converting normal C.sub.4 hydrocarbons to maleic anhydride in vapor phase, comprising as components vanadium, phosphorus, oxygen, Cu, Mo, Ni, Co, Cr, Nd, Ce, Ba, Y and Sm.

Oxidation catalysts and process for preparing anhydride from alkanes

In autoxidation of tertiary, aryl or cycloalkanes the selectivity for organic hydroperoxides can be substantially increased by using a phosphate compound of Li, Na, Mg, Ca, Sr, Fe, Cu, U or B. For example an autoxidation of isopentane with 0.05 wt. % boron phosphate at 9.9 mole % conversion gave selectivities of t-amyl hydroperoxides -- 75.0 mole %, acetone -- 18.3 mole % and t-amyl alcohol -- 1.5 mole %. The same reaction without the phosphate at 10.0 mole % conversion gave selectivities of t-amyl hydroperoxide -- 56.8 mole %, acetone -- 31.2 mole % and t-amyl alcohol -- 4.8 mole %.

Preparation of hydroperoxides by autoxidation

A catalyst complex useful for converting normal C.sub.4 hydrocarbons to maleic anhydride in vapor phase comprising as components vanadium, phosphorus, copper, an element selected from the Group of Te, Zr, Ni, Ce, W, Pd, Ag, Mn, Cr, Zn, Mo, Re, Sm, La, Hf, Ta, Th, Co, U, and Sn preferably with an alkali or alkaline earth metal.

Process for preparing maleic anhydride from C.sub.4 hydrocarbons

A catalyst complex useful for converting normal C.sub.4 hydrocarbons to maleic anhydride in vapor phase comprising as components vanadium, phosphorus, copper, an element selected from the group of Te, Zr, Ni, Ce, W, Pd, Ag, Mn, Cr, Zn, Mo, Re, Sm, La, Hf, Ta, Th, Co, U, and Sn, preferably with an alkali or alkaline earth metal.

Catalyst and process for preparing maleic anhydride from C.sub.4

Cyclic compounds, particularly cycloalkanes and cycloalkenes can be oxidized using known metal oxidation catalysts in an organic ester solvent with considerable advantage over prior art solvents. For example cyclohexane was oxidized with a combination cobalt-manganese catalyst at a conversion of 15.3 mole % to give 20.3 mole % selectivity to adipic acid. Although this is not particularly high, 70.9 mole % of the converted cyclohexane was precursors of adipic acid which on recycle to the oxidation at a conversion of 14.4 mole % (total reaction time 0.23 hours) gave 64.6 mole % selectivity to adiptic acid and a total selectivity to adipic acid and precursors of 89.2 mole %.

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Houston, TX, United States of America

Bruno J Barone