A method for preparing dimethyl 1,4-cyclohexanedicarboxylate

Abstract

The invention relates to a method for preparing dimethyl 1,4-cyclohexanedicarboxylate. The method includes: providing a continuous reactor, packed with catalyst granules of Ru / Al2O3 with particle sizebeing 1.0-5.0 mm, packing density of the catalyst granules of Ru / Al2O3 in the continuous reactor being 0.4-0.7 g / cm2, and the ruthenium dispersity of the catalyst granules of Ru / Al2O3 being higher than 13%; in the continuous reactor, carrying out hydrogeneration reaction on a reactant solution containing dimethyl terephthalate and 1,4-cyclohexanedicarboxylate and hydrogen under the pressure of 20-30 kg / cm2 to prepare the dimethyl 1,4-cyclohexanedicarboxylate. The method effectively increases conversion rate and shows excellent catalytic activity during the hydrogenation, thus reducing after-treatment cost and achieving industrial application value.

Description

technical field [0001] The invention relates to a method for preparing 1,4-cyclohexanedicarboxylate, in particular to a method for preparing 1,4-cyclohexanedicarboxylate through hydrogenation reaction. Background technique [0002] 1,4-Cyclohexanedimethanol (CHDM) is a monomer widely used in the manufacture of condensation polymers and special polyesters, and 1,4-cyclohexanedicarboxylate (DMCD) is an intermediate in the synthesis process It is important for the synthesis of 1,4-cyclohexanedimethanol. [0003] Generally, dimethyl 1,4-cyclohexanedicarboxylate is prepared from dimethyl terephthalate (DMT) by hydrogenating the benzene ring of dimethyl terephthalate to generate 1,4 -Dimethyl cyclohexanedicarboxylate; palladium-based catalysts were used as catalysts for the hydrogenation of benzene rings in the early stage, but the palladium-based catalysts need to be reacted at higher pressure and higher temperature, and the reaction preparation process needs to use such as wate...

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Problems solved by technology

[0003] Generally, dimethyl 1,4-cyclohexanedicarboxylate is prepared from dimethyl terephthalate (DMT) by hydrogenating the benzene ring of dimethyl terephthalate to generate 1,4 -Dimethyl cyclohexanedicarboxylate; palladium-based catalysts were used as catalysts for the hydrogenation of benzene rings in the early stage, but the palladium-based catalysts need to be reacted at higher pressure and higher temperature, and the reaction preparation process needs to use such as water Or aliphatic alcohol is used as the reaction solvent, resulting in cumbersome subsequent separation and treatment procedures, increasing the cost of plant construction and operating costs of the reaction; in addition, the palladium-based catalyst is prone to be poisoned by the reaction by-product carbon monoxide, which is also unfavorable for production.

[0004] Currently, the existing technology discloses the use of ruthenium-based catalysts for the hydrogenation of benzene rings, so that the hydrogenation of benzene rings can be operated in a low-pressure environment and overcomes the problem of being easily poisoned by carbon monoxide. The time limit is short, which affects the yield of the process, and when the ruthenium-based catalyst is applied to the continuous reaction, the operating pressure cannot be lower than 40 bar (bar), and the problem of expensive process cost cannot be effectively solved

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