Continuous esterification production method for mixed dibasic acid dimethyl ester

Abstract

The invention discloses a continuous esterification production method for mixed dibasic acid dimethyl ester. The method comprises the following steps of: (1) pre-esterifying, namely, mixing dibasic acid and methanol in a mole ratio of 1:2-3 and performing pre-esterification at the normal temperature and normal pressure to obtain a pre-esterified material; (2) pre-heating the methanol, namely, pressurizing and pre-heating the methanol to form overheated methanol gas with the temperature of between 145 and 155 DEG C; and (3) continuously esterifying, namely, adding the pre-esterified material into a continuous esterification reactor, of which the middle part is provided with a catalyst reaction bed, from the top, adding the overheated methanol gas into the continuous esterification reactor from the bottom, performing a reverse flow reaction on the ascending methanol gas and the descending pre-esterified material on the catalyst reaction bed, and continuously discharging the mixed dibasic acid dimethyl ester which is generated by the esterification from the bottom of the esterification reactor.

Description

Technical field [0001] The invention relates to the technical field of esterification synthesis, in particular to a continuous esterification production method of dimethyl mixed dibasic acid. Background technique [0002] Mixed Dimethyl Dibasic Acid (MDBE) is a kind of high boiling point solvent, which is the by-product dicarboxylic acid (C4, C5, C6 mixed dibasic acid) and methanol esterified by the production of adipic acid. . MDBE solvent has the characteristics of high boiling point, uniform distillation, mild odor, low toxicity and biodegradability. It has super dissolving ability and is called a universal solvent. It is compatible with polyurethane resin, acrylic resin, polyester resin, and epoxy resin. It has excellent compatibility and can widely replace ketones (such as cyclohexanone, isophorone, etc.), ethers (such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, etc.), and esters (such as glycol ethyl ether) Acetate, propylene glycol methyl ether...

AI Technical Summary

Problems solved by technology

[0005] 1. Intermittent esterification has high energy consumption, low product yield, unstable quality, and unstable impurity content and acid value in different batches of products;

[0006] 2. The intermittent esterification reaction is not complete and the product yield is low;

[0007] 3. The residence time of the mixed acid in the esterification tank is too long, resulting in the formation of a large amount of polymers, resulting in a decrease in product yield, blockage of equipment, frequent cleaning, and increased labor costs;

[0008] 4. The high molecular polymer produced by the reaction cannot be processed, causing serious pollution problems;

[0009] 5. Methanol has a lot of loss and high consumption during the reaction process;

[0010] 6. The output of intermittent production is low, which is not conducive to large-scale production