The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active material of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active materials of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.

The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active material of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube and filled with catalysts of different chemical composition wherein the active materials of the catalysts comprise vanadium and titanium dioxide and the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt. %.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

The present invention disclosed a single step process for the conversion of cyclohexane to adipic acid by using manganese oxide, tungsten oxide or Mn—WOx nano structure having improved yield and selectivity.

The present invention disclosed a single step process for the conversion of cyclohexane to adipic acid by using manganese oxide, tungsten oxide or Mn—WOx nano structure having improved yield and selectivity.

Disclosed is the oxidation of uronic acids, such as galacturonic acid, to the corresponding aldaric acids, such as galactaric acid, under neutral or acidic conditions. Use is made of a supported gold catalyst. The oxidation occurs in good selectivity and yield, under unexpectedly mild conditions. A source of galacturonic acids is pectins, such as from sugar beet pulp.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

A method of production of malic acid includes treating a first intermediate product to form a second intermediate product. The treating includes substantially removing impurities from the first intermediate product to obtain a treated intermediate product by gas stripping the crude maleic anhydride, or subjecting a mixture of one or more of the crude maleic acid, the crude fumaric acid, and the vent gas scrubber solution obtained from a phthalic anhydride production process or a maleic anhydride production process to crystallization, passing an aqueous solution of the treated intermediate product through a carbon column to substantially remove retained impurities to form the second intermediate product, obtaining a feed that includes the second intermediate product, and causing the feed to undergo hydration reaction in a tubular reactor or a continuous stirred tank reactor to produce malic acid.

A catalyst for catalytic oxidation of furfural to prepare maleic acid, relating to the technical field of renewable energy. The catalyst is a mixture of a bromide and a base. A method for preparing the catalyst in catalytic oxidation of furfural to prepare maleic acid. The method includes: mixing the furfural, the bromide-base, an oxidant and a solvent to carry out a reaction to obtain the maleic acid. The present invention has the advantages that the method has a relatively high conversion rate of furfural and a relatively high yield of maleic acid, the conversion rate of furfural is up to 99%, the yield of maleic acid is up to 68.04%; and the catalyst has a high catalytic selectivity and reusability.