The invention relates to the use of a column with a separating wall as a purification/finishing column in a (meth)acrylic acid recovery method based on the use of two distillation columns in the absence of external organic solvent. The method according to the invention improves the energy balance for the method while improving the technical quality of the (meth)acrylic acid recovered. The method according to the invention further produces polymer-grade (or glacial) (meth)acrylic acid compatible with the production of high-molecular weight acrylic acid polymers.

The invention is directed to a process for preparing maleic acid or a derivative thereof, the process comprising a step b) of oxidizing 5-hydroxy-2(5H)-furanone and/or cis--formylacrylic acid to maleic acid or a derivative thereof by contacting the 5-hydroxy-2(5H)-furanone and/or cis--formylacrylic acid with molecular oxygen (O.sub.2) in the presence of a catalyst. In a particular embodiment, the step b) is preceded by a step a) of oxidizing a furanic compound according to formula I into the 5-hydroxy-2(5H)-furanone and/or cis--formylacrylic acid, ##STR00001##
wherein R.sup.1 is H, CH.sub.2OH, CO.sub.2H or CHO and R.sup.2 is H, OH, C.sub.1-C.sub.6 alkyl or O(C.sub.1-C.sub.6 alkyl), or esters, ethers, amides, acid halides, anhydrides, carboximidates, nitriles, and salts of formula I.

The present invention provides a method for producing an oxide catalyst containing antimony, comprising

a step (A) of obtaining the oxide catalyst using antimony particles containing a diantimony trioxide as a source of the antimony,

wherein an abundance of a pentavalent antimony in a surface layer of the antimony particle to be measured in XPS analysis is less than 70 atom %, and

the antimony particle has an average particle size of 1.2 m or less.

The present invention provides an integrated system comprising: an electrocatalysis device, in which an oxidation reaction is carried out at an anode by an electrocatalysis of glycerol, and at a cathode hydrogen is produced through a reduction reaction; and a chemical catalysis device for producing butene oligomers from lignocellulosic biomass through a hydrogenation process, wherein the hydrogen produced by the electrocatalysis device is used for the production of the butene oligomers by the chemical catalysis device, and a thermal energy of the electrocatalysis device and the chemical catalysis device is exchanged with each other. The integrated system according to the present invention can reduce the cost of materials of a process for preparing butene oligomers by using hydrogen, which is a byproduct of a process for preparing glycerol derivatives, as a material of a process for preparing the butene oligomers through the integration of materials and energy from the processes for preparing glycerol derivatives and butene oligomers, and can obtain an effect of reducing energy costs by greatly reducing energy required in an integrated process by supplying, as a part of a thermal energy required at the process for preparing glycerol derivatives, the waste heat of the process for preparing the butene oligomers through the construction of a thermal energy integration network.

A method of catalytic oxidation of a lignite using oxygen as an oxidant at atmospheric pressure is provided. The method includes the following steps, pulverizing the lignite to 200-mesh or less; drying the pulverized lignite at a temperature of 80 C. in vacuum for 10 h; weighing 0.5 g of the dried lignite and sequentially adding 10 ml of acetic acid, 0.5 mmol of a catalyst and 0.15-0.25 mmol of a cocatalyst into a round-bottom flask filled with the oxygen, keeping oxygen pressure at 0.1 MPa, reacting at a temperature of 80-120 C. for 4-12 h; using oxygen as the oxidant to catalytically oxidize the reacted lignite at an atmospheric pressure of 0.1 MPa; filtering after the reaction is finished; decompressing the filtrate to remove the acetic acid, adding a small amount of ethyl acetate to dissolve, and using an excess CH.sub.2N.sub.2/ether solution to esterify for 10 h at room temperature; and analyzing the esterified product through a gas chromatography-mass spectrometer.

A method of catalytic oxidation of a lignite using oxygen as an oxidant at atmospheric pressure is provided. The method includes the following steps, pulverizing the lignite to 200-mesh or less; drying the pulverized lignite at a temperature of 80 C. in vacuum for 10 h; weighing 0.5 g of the dried lignite and sequentially adding 10 ml of acetic acid, 0.5 mmol of a catalyst and 0.15-0.25 mmol of a cocatalyst into a round-bottom flask filled with the oxygen, keeping oxygen pressure at 0.1 MPa, reacting at a temperature of 80-120 C. for 4-12 h; using oxygen as the oxidant to catalytically oxidize the reacted lignite at an atmospheric pressure of 0.1 MPa; filtering after the reaction is finished; decompressing the filtrate to remove the acetic acid, adding a small amount of ethyl acetate to dissolve, and using an excess CH.sub.2N.sub.2/ether solution to esterify for 10 h at room temperature; and analyzing the esterified product through a gas chromatography-mass spectrometer.

A method of catalytic oxidation of a lignite using oxygen as an oxidant at atmospheric pressure is provided. The method includes the following steps, pulverizing the lignite to 200-mesh or less; drying the pulverized lignite at a temperature of 80 C. in vacuum for 10 h; weighing 0.5 g of the dried lignite and sequentially adding 10 ml of acetic acid, 0.5 mmol of a catalyst and 0.15-0.25 mmol of a cocatalyst into a round-bottom flask filled with the oxygen, keeping oxygen pressure at 0.1 MPa, reacting at a temperature of 80-120 C. for 4-12 h; using oxygen as the oxidant to catalytically oxidize the reacted lignite at an atmospheric pressure of 0.1 MPa; filtering after the reaction is finished; decompressing the filtrate to remove the acetic acid, adding a small amount of ethyl acetate to dissolve, and using an excess CH.sub.2N.sub.2/ether solution to esterify for 10 h at room temperature; and analyzing the esterified product through a gas chromatography-mass spectrometer.

Provided are a lignin degradation catalyst that exhibits excellent lignin degradability and that is readily separated after degradation reaction, a method for producing the catalyst, and a method for degrading lignin. The lignin degradation catalyst according to the present invention contains a substrate and at least one metal compound immobilized on the substrate, wherein the at least one metal compound contains a copper compound. The method for producing a lignin degradation catalyst according to the present invention includes the step of brining a porous copper substrate into contact with a solution containing an oxidant to obtain a substrate having a copper compound immobilized thereon, or the step of subjecting a porous copper substrate to electro-oxidation to obtain a substrate having a copper compound immobilized thereon.

Provided are a lignin degradation catalyst that exhibits excellent lignin degradability and that is readily separated after degradation reaction, a method for producing the catalyst, and a method for degrading lignin. The lignin degradation catalyst according to the present invention contains a substrate and at least one metal compound immobilized on the substrate, wherein the at least one metal compound contains a copper compound. The method for producing a lignin degradation catalyst according to the present invention includes the step of brining a porous copper substrate into contact with a solution containing an oxidant to obtain a substrate having a copper compound immobilized thereon, or the step of subjecting a porous copper substrate to electro-oxidation to obtain a substrate having a copper compound immobilized thereon.

Disclosed is a method of catalytic oxidation of lignite using oxygen as an oxidant at atmospheric pressure, belonging to a method of mild oxidation of lignite. The method is used to mildly oxidize the lignite using the oxygen as the oxidant under the action of a nitroxide radical catalyst and a metal salt or metal oxide cocatalyst; the process comprises the following steps: pulverizing the lignite to 200 meshes or less, drying a pulverized coal sample at a temperature of 80 C. in vacuum for 10 h, weighing 0.5 g of the treated coal sample, sequentially adding 10 ml of acetic acid, 0.5 mmol of a catalyst and 0.15 to 0.25 mmol of a cocatalyst into a round-bottom flask, connecting a tee joint to an upper orifice of a condenser pipe, replacing oxygen in vacuum for three times so that the round-bottom flask is filled with the oxygen, keeping oxygen pressure at 0.1 MPa, reacting at a temperature of 80 C. to 120 C. for 4 to 12 h; filtering after the reaction is finished; decompressing a filtrate to remove the acetic acid, adding a small amount of ethyl acetate to dissolve, then using an excess CH.sub.2N.sub.2/ether solution to esterify for 10 h at room temperature, using 0.45 m filter paper to filter, and analyzing an esterified product through a gas chromatography-mass spectrometer. The method has the advantages of using the oxygen as the oxidant, having low price, having no toxicity, and achieving environmental protection and mild conditions.