Method for preparing 1,4-cyclohexanedimethanol from dimethyl 1,4-cyclohexanedicarboxylates through hydrogenation

Abstract

The invention discloses a method for preparing 1,4-cyclohexanedimethanol (CHDM) from dimethyl 1,4-cyclohexanedicarboxylates (DMCD) through hydrogenation. Liquid phase DMCD serving as a raw material and hydrogen serving as a reducing agent sequentially pass through a first single-tube reactor and a second single-tube reactor which are loaded with catalysts, and performing gas-liquid-solid three-phase reaction to obtain a 1,4-cyclohexanedimethanol product; the catalysts loaded in the two single-tube reactors are Cu-Zn-Al catalysts; the reaction temperature of the two single-tube reactors is 150 to 240 DEG C, and the reaction temperature of the second single-tube reactor is more than or equal to the reaction temperature of the first single-tube reactor; the pressure in the two single-tube reactors are equal and are 4.0 to 12.0 MPa; the hydrogen oil molar ratio of the second single-tube reactor is more than that of the first single-tube reactor; the airspeed of the DMCD relative to the total amount of the catalysts loaded in the first single-tube reactor and the second single-tube reactor is 0.1 to 1.5 h<-1>; and compared with the prior art, the method has the advantages that the reaction energy consumption can be remarkably reduced, the capacity can be improved, and the conversion rate and the selectivity of the DMCD in the reaction process of preparing the CHDM through hydrogenation can be increased and improved.

Description

technical field [0001] The invention relates to a method for preparing 1,4-cyclohexanedimethanol by hydrogenating dimethyl 1,4-cyclohexanedicarboxylate. Background technique [0002] 1,4-Cyclohexanedimethanol (CHDM) is an intermediate of saturated polyester and unsaturated polyester in coatings, inks, adhesives, insulating materials and some special purposes. It is an important new raw material for polyester production in industry. The biggest application is to synthesize PETG copolyester, and then obtain sheet, thick material and other products through extrusion or injection molding. The product has good transparency and impact resistance. durability, abrasion resistance and corrosion resistance. Used in the manufacture of polyester fibers, polyester electrical appliances, unsaturated polyester resins, polyester glazes, polyurethane foams, and the production of lubricants and hydraulic fluids. [0003] In the mid-1990s, through the advancement of catalyst technology, East...

AI Technical Summary

Problems solved by technology

[0005] To sum up, in DMCD, the mass transfer and heat transfer efficiency of liquid-phase hydrogenation is far lower than that of gas-phase hydrogenation, resulting in conversion and selectivity inferior to gas-phase hydrogenation mode, but liquid-phase hydrogenation has obvious advantages in terms of energy consumption and production capacity. The advantages