TWO-STAGE METHOD FOR HYDROGENATION OF MALEIC ACID TO 1,4-BUTANEDIOL Russian patent published in 2007 - IPC C07C51/36 C07C55/10 C07C29/149 C07C31/20 C07D307/33 C07D307/08 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to improved method (variants) for conversion of maleic acid to 1,4-butanediol, gamma-butyrolactone and/or tetrahydrofuran. Method for synthesis for at least one of product chosen from a group comprising gamma-butyrolactone, 1,4-butanediol and tetrahydrofuran involves the following steps: creature of the first hydrogenation zone and the second hydrogenation zone that are bound successively; feeding to the first zone of a raw flow that comprises maleic acid; caring out reaction in the first hydrogenation zone of the parent maleic acid and hydrogen in contact with a catalyst to yield the reaction product comprising succinic acid; feeding to the second zone the hydrogenation product from the first hydrogenation zone; carrying out the hydrogenation reaction of the reaction product obtained in the first hydrogenation zone in the second hydrogenation zone in contact with a catalyst for preparing a product that comprises at least one product from a group comprising gamma-butyrolactone, 1,4-butanediol and tetrahydrofuran. Method involves control over temperature in first hydrogenation zone by manner that maleic acid temperature in the raw flow and temperature in the first hydrogenation zone doesn't exceed 120^°C, and the reaction heat liberated in the first hydrogenation zone is used in enhancing the reaction product reaction above 130°C before feeding the reaction product from the first hydrogenation zone to the second hydrogenation zone resulting to minimal corrosion effect of maleic acid and enhancing time for working life of reactor and improving the complete effectiveness of the process.

EFFECT: improved method of synthesis.

13 cl, 1 ex