A kind of method for preparing dibasic acid dimethyl ester

Abstract

The invention discloses a preparation method for diacid dimethyl ester. The method comprises the following steps: adding diacid, recycled diacid monomethyl ester and methanol into a mixing tank and carrying out heating, dissolving and uniform mixing so as to obtain a feeding mixture; preheating the feeding mixture with a preheater, allowing the preheated feeding mixture to enter an esterification reactor from the bottom of the reactor and enabling the feeding mixture to undergo an esterification reaction under catalysis of a catalyst so as to prepare a reaction mixture; and discharging the prepared reaction mixture from the top of the reactor and allowing the reaction mixture to successively pass through a methanol rectifying tower, a water rectifying tower and a diacid dimethyl ester rectifying tower so as to respectively separate methanol, water and diacid dimethyl ester. The method has the advantages of mild reaction conditions, high yield, a high utilization rate of raw materials and low energy consumption.

Description

technical field [0001] The invention relates to a method for preparing dimethyl dibasic acid, which belongs to the field of preparation of mixed esters. Background technique [0002] Dimethyl dibasic acid is an excellent plasticizer and an important high-boiling point solvent. This kind of substance is easy to biodegrade and has good environmental protection. [0003] Existing technologies for producing dimethyl dibasic acid generally use inorganic acids as catalysts. Inorganic acids severely corrode equipment and have poor environmental protection. Some existing processes adopt batch reaction, and its operation is complicated, which is not conducive to large-scale production. These problems need to be solved urgently. [0004] At present, the novel method for producing dibasic acid dimethyl ester is as described in Chinese patent application document CN101891610A and Chinese patent CN200710064315.2. The disclosed process is: after pre-esterifying the mixed dibasic acid an...

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Problems solved by technology

[0008] 3. Due to the need for pre-esterification and the use of a large amount of superheated methanol steam, the energy consumption is very high

[0009] The catalyst used in the Chinese patent application document CN101891610A is ferric chloride or sodium bisulfate, both of which have strong hygroscopicity and are easy to absorb water and deliquesce, so the fixed bed cannot run for a long period of time

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