A catalyst for catalytic oxidation of furfural to prepare maleic acid is composed of a carbon nitride doped with a potassium salt. A method for preparing the catalyst includes mixing the potassium salt, a precursor of the carbon nitride and a solvent to obtain a mixture, and drying and calcining the mixture to obtain the catalyst. A use of the catalyst in catalytic oxidation of furfural to prepare maleic acid, wherein the maleic acid is prepared by the step of oxidizing furfural in a solvent in the presence of the catalyst. The invention has the advantages that by using the method provided by the invention to prepare maleic acid, the conversion rate of furfural can be 99% or more and the yield of maleic acid can be up to 70.40%.

A two-stage process produces tetraalkyl 1,2,3,4-butanetetracarboxylates having alkyl groups with 1 to 6 carbon atoms starting from tetrahydrophthalic anhydride (THPA). The process starts with an oxidation of tetrahydrophthalic anhydride (THPA), followed by a subsequent esterification of the resulting 1,2,3,4-butanetetracarboxylic acid with an alcohol having 1 to 6 carbon atoms.

A two-stage process produces tetraalkyl 1,2,3,4-butanetetracarboxylates having alkyl groups with 1 to 6 carbon atoms starting from tetrahydrophthalic anhydride (THPA). The process starts with an oxidation of tetrahydrophthalic anhydride (THPA), followed by a subsequent esterification of the resulting 1,2,3,4-butanetetracarboxylic acid with an alcohol having 1 to 6 carbon atoms.

A two-stage process produces tetraalkyl 1,2,3,4-butanetetracarboxylates having alkyl groups with 1 to 6 carbon atoms starting from tetrahydrophthalic anhydride (THPA). The process starts with an oxidation of tetrahydrophthalic anhydride (THPA), followed by a subsequent esterification of the resulting 1,2,3,4-butanetetracarboxylic acid with an alcohol having 1 to 6 carbon atoms.

The present disclosure discloses an immobilized metalloporphyrin catalyst and its utilization in maleic acid preparation, belonging to the technical field of metalloporphyrin catalytic application. The immobilized metalloporphyrin catalyst is used for catalyzing furfural to prepare maleic acid and is good in catalytic effect, mild in reaction conditions and capable of greatly reducing the energy consumption required in the prior art. The catalyst disclosed by the present disclosure can provide a good microenvironment for a reaction, so that the yield and selectivity of maleic acid are increased; and according to a method disclosed by the present disclosure, the conversion ratio of furfural is 20.4%-95.6%, the yield of maleic acid is 10%-56.1%, and the selectivity is 43.6%-76.1%. Meanwhile, the catalyst is easy to separate and environmentally friendly and may be recycled for many times.

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.

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.

A method for producing dicarboxylic acid. The method includes: subjecting a raw material system including a cyclic olefin and a lower monocarboxylic acid to an addition reaction in the presence of an addition reaction catalyst to generate an intermediate product system including cyclic carboxylic acid ester; and subjecting the intermediate product system including cyclic carboxylic acid ester to a ring-opening and oxidation reaction in the presence of an oxidant and an oxidation catalyst to generate a corresponding dicarboxylic acid product. The addition reaction in the dicarboxylic acid synthesis route achieves a high single-pass conversion rate, and the selectivity of the corresponding cyclic carboxylic acid ester is high. The addition-oxidation synthesis route achieves faster reaction rates for both the addition reaction and oxidation reaction, and high yield of corresponding dicarboxylic acid product. The addition-oxidation based synthesis route is suitable for continuous, stable and large-scale production of corresponding dicarboxylic acid product.

A method for producing dicarboxylic acid. The method includes: subjecting a raw material system including a cyclic olefin and a lower monocarboxylic acid to an addition reaction in the presence of an addition reaction catalyst to generate an intermediate product system including cyclic carboxylic acid ester; and subjecting the intermediate product system including cyclic carboxylic acid ester to a ring-opening and oxidation reaction in the presence of an oxidant and an oxidation catalyst to generate a corresponding dicarboxylic acid product. The addition reaction in the dicarboxylic acid synthesis route achieves a high single-pass conversion rate, and the selectivity of the corresponding cyclic carboxylic acid ester is high. The addition-oxidation synthesis route achieves faster reaction rates for both the addition reaction and oxidation reaction, and high yield of corresponding dicarboxylic acid product. The addition-oxidation based synthesis route is suitable for continuous, stable and large-scale production of corresponding dicarboxylic acid product.

A method for producing dicarboxylic acid. The method includes: subjecting a raw material system including a cyclic olefin and a lower monocarboxylic acid to an addition reaction in the presence of an addition reaction catalyst to generate an intermediate product system including cyclic carboxylic acid ester; and subjecting the intermediate product system including cyclic carboxylic acid ester to a ring-opening and oxidation reaction in the presence of an oxidant and an oxidation catalyst to generate a corresponding dicarboxylic acid product. The addition reaction in the dicarboxylic acid synthesis route achieves a high single-pass conversion rate, and the selectivity of the corresponding cyclic carboxylic acid ester is high. The addition-oxidation synthesis route achieves faster reaction rates for both the addition reaction and oxidation reaction, and high yield of corresponding dicarboxylic acid product. The addition-oxidation based synthesis route is suitable for continuous, stable and large-scale production of corresponding dicarboxylic acid product.