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.

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.

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 system and method for the conversion of a levulinate ester to maleic anhydride using a reducible oxide catalyst. Levulinic acid oxidation delivers maleic anhydride in good yields without viscosity and stability issues that make continuous production problematic. Due to the fact that levulinate esters are more amenable to processing, the conversion of levulinate esters to maleic anhydride represents an appropriate for the commercial production of maleic anhydride from renewable resources.

The present invention relates to a method for preparing hydrocarbon double acids using a cyclic hydrocarbon oxidation catalyst, wherein adipic acid and dodecanedioic acid may be produced with high yield while solving the problem of environmental pollution, the adipic acid and the dodecanedioic acid being prepared by using an oxidation reaction of a cyclohexane-cyclohexanone mixture and an oxidation reaction of a cyclododecane-cyclododecanone mixture, respectively, in the presence of a vanadium phosphate oxide-based catalyst and/or a cobalt-manganese oxide-based catalyst.

The present invention relates to a method for preparing hydrocarbon double acids using a cyclic hydrocarbon oxidation catalyst, wherein adipic acid and dodecanedioic acid may be produced with high yield while solving the problem of environmental pollution, the adipic acid and the dodecanedioic acid being prepared by using an oxidation reaction of a cyclohexane-cyclohexanone mixture and an oxidation reaction of a cyclododecane-cyclododecanone mixture, respectively, in the presence of a vanadium phosphate oxide-based catalyst and/or a cobalt-manganese oxide-based catalyst.

The present invention discloses an improved oxidation process using carbon nitride nanotubes as metal free catalyst and molecular O2 as the oxidant to obtain desired adipic acid and other oxygenated hydrocarbons with improved conversion and selectivity.

The present invention discloses an improved oxidation process using carbon nitride nanotubes as metal free catalyst and molecular O2 as the oxidant to obtain desired adipic acid and other oxygenated hydrocarbons with improved conversion and selectivity.

The invention relates to an oxidation catalyst comprising at least one inorganic, oxidic or ceramic, shaped support body having a BET surface area of less than 0.5 m.sup.2/g, based on the support, which is at least partly coated with a catalytically active multielement oxide, the catalyst being precious metal-free and the shaped support body having the form of a saddle whose saddle surface is curved oppositely in the two principal directions, to a process for producing it, to its use in various catalytic gas phase oxidations, and to corresponding processes for catalytic gas phase oxidation.

Methods of depolymerizing lignin and products obtained therefrom. The methods include reacting lignin in a liquid solvent comprising an oxidation catalyst with the solvent being in contact with O.sub.2 gas. The solvent can include aprotic polar solvents. The oxidation catalyst can include heterogeneous catalysts. The methods can be used in the oxidative catalytic fractionation of raw biomass to generate soluble aromatic monomers and a solid carbohydrate residue. Depolymerized lignin products include phenolic and benzoquinone monomers, such as p-hydroxybenzoic acid, vanillin, syringaldehyde, vanillic acid, and/or syringic acid.