Abstract: Disclosed is a process for the preparation of a modified vanadium/phosphorus mixed oxide catalyst for the partial oxidation of n-butane to maleic anhydride. The catalyst comprises vanadyl pyrophosphate as main component and niobium as a promoter element in an amount corresponding to an atomic ratio of vanadium to niobiurn in the range of 250:1 to 60:1. The catalyst exhibits improved activity, improved yield of maleic anhydride, and optimal performance from the very beginning of its catalytic lifetime.

Abstract: An improved process for the production of maleic anhydride by the catalytic oxidation of n-butane. Maleic anhydride is produced by reacting n-butane gas with oxygen gas or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide catalyst. A trialkyl phosphite or trialkyl phosphate component is continuously added to the gases in an amount of from about 0.5 ppm to about 4 ppm by weight of elemental phosphorus in the trialkyl phosphate or trialkyl phosphite component. Heat is applied to the gases at a temperature of from about 400° C. to about 440° C. while maintaining a maximum temperature of gases present in the reaction of about 480° C. A simultaneous conversion of n-butane to maleic anhydride of about 84% or more and a conversion of n-butane to by-product acrylic acid of about 1.5% or less is achieved.

Abstract: Catalytic compositions of oxides of titanium, vanadium and tin that are suitable for the production of phthalic anhydride by oxidizing o-xylene and/or naphthalene in the gas phase. The catalysts exhibit excellent activity and selectivity. The catalyst contains 2 to 15 percent by weight (calculated as V2O5) of vanadium, 1 to 15 percent weight (calculated as SnO2) of tin and 70 to 97 percent by weight (calculated as TiO2) of titanium. In a preferred embodiment the catalyst also contains up to 5 percent by weight (calculated as M2O) of at least one alkali metal, preferably lithium, potassium or rubidium, and more preferably cesium. In an even more preferred embodiment, cesium is present in an amount of from 0.01 to 2 percent by weight (calculated as Cs2O).

Abstract: An improved process for the production of maleic anhydride by the catalytic oxidation of n-butane. Maleic anhydride is produced by reacting n-butane gas with oxygen gas or an oxygen-containing gas, in the presence of a vanadium phosphorus oxide catalyst. A trialkyl phosphite or trialkyl phosphate component is continuously added to the gases in an amount of from about 0.5 ppm to about 4 ppm by weight of elemental phosphorus in the trialkyl phosphate or trialkyl phosphite component. Heat is applied to the gases at a temperature of from about 400° C. to about 440° C. while maintaining a maximum temperature of gases present in the reaction of about 480° C. A simultaneous conversion of n-butane to maleic anhydride of about 84% or more and a conversion of n-butane to by-product acrylic acid of about 1.5% or less is achieved.

Abstract: Disclosed is a process for the preparation of a modified vanadium/phosphorus mixed oxide catalyst for the partial oxidation of n-butane to maleic anhydride. The catalyst comprises vanadyl pyrophosphate as main component and niobium as a promoter element in an amount corresponding to an atomic ratio of vanadium to niobiurn in the range of 250:1 to 60:1. The catalyst exhibits improved activity, improved yield of maleic anhydride, and optimal performance from the very beginning of its catalytic lifetime.

Abstract: Disclosed are catalytic compositions comprising oxides of titanium vanadium and tin which are suitable for the production of phthalic anhydride by oxidizing o-xylene and/or napthalene in the gas phase. The catalysts exibit excellent activity and selectivity. The catalyst comprise 2 to 15% by weight (calculated as V2O5) of vanadium, from 1 to 15% by weight (calculated as SnO2) of tin and further comprise from 70 to 97% by weight (calculated as TiO2) of titanium. In a preferred embodiment the catalyst of the invention comprise up to 5% by weight (calculated as M2O) of at least tine alkali metal preferably lithium, potassium or rubidium, and more preferably cesium. In an even more preferred embodiment, cesium is present in an amount of from 0.01 to 2% by weight (calculated as Cs2O).

Abstract: Active vanadium/phosphorus mixed oxide catalyst for the conversion of non-aromatic hydrocarbons, e.g., n-butane, into maleic anhydride. The catalyst is prepared from the catalyst precursor, that is, prepared by the reaction of a source of vanadium in an organic medium in the presence of a phosphorus source. The organic medium is (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol. The catalyst precurso is transformed into the active catalyst by an activation process that includes a heat treatment that includes applying a temperature of up to 600° C.

Abstract: A process for preparing a catalyst for maleic anhydride production wherein a +5 vanadium compound such as V2O5, an anhydrous phosphoric acid, and optionally promoters are admixed in an organic alcohol solvent, the admixture is rapidly brought to reflux and thereafter refluxed to reduced the vanadium compound to the desired degree, the reflux mixture is cooled, precursor crystals are separated by filtration and then dried and calcined.

Abstract: Active vanadium/phosphorus mixed oxide catalyst for the conversion of non-aromatic hydrocarbons, e.g., n-butane, into maleic anhydride. The catalyst is prepared from the catalyst precursor, that is, prepared by the reaction of a source of vanadium in an organic medium in the presence of a phosphorus source. The organic medium is (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol. The catalyst precursor is transformed into the active catalyst by an activation process that includes a heat treatment that includes applying a temperature of up to 600° C.

Abstract: A process for the preparation of a vanadium/phosphorus mixed oxide catalyst precursor is described, comprising the reaction of a vanadium source in selected organic media in the presence of a phophorus source. The medium comprises: (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol in the weight ratio (a) to (b) of 99:1 to 5:95. After its activation, the vanadium/phosphorus mixed oxide catalyst precursor is an excellent catalyst in the conversion of non-aromatic hydrocarbons like n-butane to malic anhydride.

Abstract: A vanadium/phosphorus mixed oxide catalyst precursor is transformed into the active catalyst for the production of maleic anhydride. The activation takes place in a fluidized bed and includes the steps of (a) initially heating the precursor; (b) further heating under superatmospheric pressure; (c) isothermal stage at superatmospheric pressure; and, finally, (d) cooling the activated catalyst obtained. Catalysts activated according to this procedure show high performance in the conversion of non-aromatic hydrocarbons to maleic anhydride.