Method for preparing 1,3-cyclohexanedione through gas-phase hydrogenation of resorcinol

Abstract

The invention provides a method for preparing 1,3-cyclohexanedione through gas-phase hydrogenation of resorcinol. The method comprises the following steps: dissolving resorcinol in benzene, then subjecting the dissolved resorcinol to direct vaporization, and mixing the vaporized resorcinol with hydrogen; allowing a mixture obtained in the previous step to pass through a fixed-bed reactor filled with an activated carbon-supported palladium catalyst at a mass space velocity of 0.1 / h to 0.7 / h, and controlling a molar ratio of hydrogen to phenol to be 2 / 1 to 10 / 1, a reaction temperature to be 180-280 DEG C and a reaction pressure of 1.0-2.0 MPa; and condensing a product obtained in the previous step with a condenser so as to obtain the hydrogenation product, i.e., 1,3-cyclohexanedione. As themethod is used for preparation of 1,3-cyclohexanedione, the conversion rate of resorcinol is up to 99.9%, and the selectivity of 1,3-cyclohexanedione is up to 97.8%.

Description

technical field [0001] The invention relates to a method for preparing 1,3-cyclohexanedione by gas-phase hydrogenation of resorcinol, which belongs to the technical field of chemical synthesis. Background technique [0002] 1,3-Cyclohexanedione is a class of important chemical intermediates, which can be used to synthesize carvedilol, a special drug for protecting cardiovascular and cerebrovascular, and treating hypertension, and anthrandansetone, an antiemetic drug. It can also be used to synthesize cosmetics, Polymer additives, excellent herbicides mesotrione and sulcotrione, etc. [0003] There are two main methods for the synthesis of 1,3-cyclohexanedione. One is to use sodium alkoxide as the condensing agent and amides as the reaction medium to synthesize 1,3-cyclohexanedione by cyclization of γ-acetylbutyrate and The condensation method of α, β-unsaturated carboxylic acid ester and ketone to synthesize 1,3-cyclohexanedione (US3922307, 1975; US 4028417, 1977); the othe...

AI Technical Summary

Problems solved by technology

The post-processing of these two methods is complicated, the product yield is not high, and there are more three wastes, which pollute the environment

[0004] Chinese patent CN 104860802 discloses a method for preparing 1,3-cyclohexanedione by selective catalytic hydrogenation of palladium graphene. This method avoids the use of organic matter and inorganic salts, and overcomes the complexity of raw materials and by-products in the traditional process. Many, serious environmental pollution and other defects, but because the process includes filtering and removing the catalyst from the reaction product, not only the operation is troublesome, but also in order to eliminate the influence of the hydrogen mass transfer process on the reaction rate, the process requires vigorous stirring, which leads to metal loss of catalyst