Disclosed is a method for linkage recovery of an organic acid in an aqueous organic acid solution. The method comprises: mixing a solution with an organic acid concentration lower than 20 wt % with a specific extractant and then subjecting same to counter-current extraction so as to obtain an extract phase and a raffinate phase; and subjecting the extract phase together with a solution with an acid concentration higher than 70 wt % to an azeotropic rectification so as to recover an organic acid. When the concentration of the aqueous organic acid solution is 20 wt %-70 wt %, the aqueous organic acid solution is extracted and concentrated to make the concentration of the aqueous organic acid solution higher than 70 wt %.

Disclosed is a method for linkage recovery of an organic acid in an aqueous organic acid solution. The method comprises: mixing a solution with an organic acid concentration lower than 20 wt % with a specific extractant and then subjecting same to counter-current extraction so as to obtain an extract phase and a raffinate phase; and subjecting the extract phase together with a solution with an acid concentration higher than 70 wt % to an azeotropic rectification so as to recover an organic acid. When the concentration of the aqueous organic acid solution is 20 wt %-70 wt %, the aqueous organic acid solution is extracted and concentrated to make the concentration of the aqueous organic acid solution higher than 70 wt %.

Disclosed is a method of producing hydrogen (H.sub.2) gas and calcium carbonate from formaldehyde. The method includes combining an aqueous base, formaldehyde, and a transition metal complex having a coordination bond between a transition metal and a leaving group to form a homogeneous aqueous solution having a basic pH, wherein the leaving group dissociates from the transition metal complex in response to light and/or the basic pH of the solution, producing hydrogen (H.sub.2) gas and formate or a salt thereof from the formaldehyde present in the homogeneous aqueous solution, and producing calcium carbonate using the formate or salt thereof as a carbon source.

Disclosed is a method of producing hydrogen (H.sub.2) gas and calcium carbonate from formaldehyde. The method includes combining an aqueous base, formaldehyde, and a transition metal complex having a coordination bond between a transition metal and a leaving group to form a homogeneous aqueous solution having a basic pH, wherein the leaving group dissociates from the transition metal complex in response to light and/or the basic pH of the solution, producing hydrogen (H.sub.2) gas and formate or a salt thereof from the formaldehyde present in the homogeneous aqueous solution, and producing calcium carbonate using the formate or salt thereof as a carbon source.

Disclosed herein is a method for selectively reducing, using electrical energy, CO.sub.2 to formic acid, a catalyst for use in the method, and an electrochemical reduction system. The method for producing formic acid by electrochemically reducing carbon dioxide of the present invention includes (a) reacting carbon dioxide with a metal complex represented by formula (1), and (b) applying a voltage to a reaction product of the carbon dioxide and the metal complex represented by formula (1):

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Disclosed herein is a method for selectively reducing, using electrical energy, CO.sub.2 to formic acid, a catalyst for use in the method, and an electrochemical reduction system. The method for producing formic acid by electrochemically reducing carbon dioxide of the present invention includes (a) reacting carbon dioxide with a metal complex represented by formula (1), and (b) applying a voltage to a reaction product of the carbon dioxide and the metal complex represented by formula (1):

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This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

A method for preparing methyl formate in which a raw material containing formaldehyde, methanol and/or dimethyl ether is introduced into a first reaction zone to come into contact with a catalyst A, and a component I is obtained by separation, the component I is introduced into a second reaction zone to come into contact with a catalyst B so as to obtain, by separation, methyl formate as a product, dimethyl ether that is returned to the first reaction zone and a component II that is returned to the second reaction zone, the catalysts have a long service life, the reaction conditions are mild, and the utilization rate of the raw material is high, thus enabling a continuous production for large-scale industrial application.

The present invention is intended to provide a method that can produce an oxidation reaction product of a hydrocarbon or a derivative thereof in an aqueous phase using a hydrocarbon or a derivative thereof as a raw material. In order to achieve the above object, the method for producing an oxidation reaction product of a hydrocarbon or a derivative thereof of the present invention includes the step of: irradiating a reaction system with light in a presence of a raw material and a halogen oxide radical to react, wherein the raw material is a hydrocarbon or a derivative thereof, the reaction system is a reaction system containing an aqueous phase, the aqueous phase contains the raw material and the halogen oxide radical, and in the reaction step, the raw material is oxidized to produce an oxidation reaction product of the raw material.