Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C.sub.2-C.sub.7 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C.sub.2-C.sub.7 aldonic acid and/or lactone(s) thereof and/or a C.sub.2-C.sub.7 aldose are described.

Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C.sub.2-C.sub.7 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C.sub.2-C.sub.7 aldonic acid and/or lactone(s) thereof and/or a C.sub.2-C.sub.7 aldose are described.

Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C.sub.5-C.sub.6 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C.sub.5-C.sub.6 aldonic acid and/or lactone(s) thereof and/or a C.sub.5-C.sub.6 aldose are described.

Various processes for preparing aldaric acids, aldonic acids, uronic acids, and/or lactone(s) thereof are described. For example, processes for preparing a C.sub.5-C.sub.6 aldaric acid and/or lactone(s) thereof by the catalytic oxidation of a C.sub.5-C.sub.6 aldonic acid and/or lactone(s) thereof and/or a C.sub.5-C.sub.6 aldose are described.

A catalyst may suppress pressure loss and coaking and produce a target substance in high yield when a gas-phase catalytic oxidation reaction of a material substance is conducted using the catalyst to produce the target substance. A ring-shaped catalyst may have a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

The present disclosure belongs to the technical field of separation and purification of glycolic acid, and in particular, to a method and device for separation and purification of glycolic acid by a rectification-crystallization coupling process and use. Bio-based platform compound molecules are used as raw materials to synthesize the glycolic acid, and the obtained crude glycolic acid is separated and purified using the rectification-crystallization coupling process to obtain high-purity glycolic acid. The method initiates system separation and purification under a new glycolic acid synthesis route, which has the difficulty that the glycolic acid is easy to polymerize during concentration, so there are technical barriers to equipment design of vacuum rectification and adjustment of process parameters. In addition, during crystallization, there are technical barriers to equipment design of a crystallization kettle and adjustment of process parameters.

The present disclosure belongs to the technical field of separation and purification of glycolic acid, and in particular, to a method and device for separation and purification of glycolic acid by a rectification-crystallization coupling process and use. Bio-based platform compound molecules are used as raw materials to synthesize the glycolic acid, and the obtained crude glycolic acid is separated and purified using the rectification-crystallization coupling process to obtain high-purity glycolic acid. The method initiates system separation and purification under a new glycolic acid synthesis route, which has the difficulty that the glycolic acid is easy to polymerize during concentration, so there are technical barriers to equipment design of vacuum rectification and adjustment of process parameters. In addition, during crystallization, there are technical barriers to equipment design of a crystallization kettle and adjustment of process parameters.

Proposed is a high-yield simultaneous conversion method for a hydrogen source and a carbon dioxide source. The method significantly increases a yield of a formate through conversion of carbon dioxide. To this end, a carbon dioxide source and a hydrocarbon containing one or more hydroxy groups undergo a simultaneous conversion reaction in the presence of a solvent containing one or more alcohols and having a pH of 10 to 14.

Proposed is a high-yield simultaneous conversion method for a hydrogen source and a carbon dioxide source. The method significantly increases a yield of a formate through conversion of carbon dioxide. To this end, a carbon dioxide source and a hydrocarbon containing one or more hydroxy groups undergo a simultaneous conversion reaction in the presence of a solvent containing one or more alcohols and having a pH of 10 to 14.

The invention relates to a method for catalytically producing an alkyl formate, wherein at least one alpha-hydroxy aldehyde, at least one alpha-hydroxy carboxylic acid, at least one carbohydrate, and/or at least one glycoside is reacted by means of a vanadium-oxygen compound, which contains vanadium in the oxidation stage +IV or +V, or a salt thereof as a catalyst in the solution, wherein the solution contains an alkanol, and the alkyl formate produced as a reaction product is separated from at least one other resulting reaction product. The catalyst which is reduced during the catalytic reaction is restored to its starting state in an oxidation process.