Preparing method for mixed dibasic acid ester from adipic acid production waste liquid and treatment method for the waste liquid

Abstract

The invention discloses a making method of binary acid ester through waste liquid of adipic acid and disposing method of waste liquid, which comprises the following steps: adding concentrated nitric acid into BI waste liquid; decomposing butylacetic acid hydrogen peroxidate into hydroxy capronate under 70-110 deg.c; aerating NO2 into decomposing liquid to trigger oxidization reaction; maintaining temperature between 70 and 110 deg.c; condensing reactant to 20-50%; evaporating DBA waste liquid to 20-50% under normal pressure; flashing with BI oxidizing condensate; cooling to 50-70 deg.c; reacting composite liquid and esterified carbinol with the same weight to extract; washing extracting phase; rectifying in the vacuum under 20-60kPa; rectifying rough composite dibasic acid dimethyl ester under 2-15kPa; evaporating water to 20-50%; circulating in the esterifying autoclave to do secondary esterification; making total transmitting rate of diacid over 90%.

Description

technical field [0001] The invention belongs to the technical field of preparation of mixed dibasic acid esters, and more specifically relates to the design of a method for preparing mixed dibasic acid esters from adipic acid production waste liquid and the waste liquid. Background technique [0002] Two streams of waste streams are generated during the process of producing adipic acid from cyclohexane. One of the waste liquids is a colorless liquid produced during the air oxidation of cyclohexane to generate cyclohexanone and cyclohexanol (KA oil), with a water content of about 75% (mass percentage, the same below), containing hexanoic acid About 9% of hydrogen oxide, about 8% of dicarboxylic acids such as succinic acid, glutaric acid, and adipic acid, about 4% of monocarboxylic acids such as formic acid and acetic acid, and neutrals such as alcohols, ketones, and lactones The component is about 3%, which is called BI waste liquid; the other waste liquid is a yellow liquid...

AI Technical Summary

Problems solved by technology

This method does not involve the decomposition of hexanoic acid hydrogen peroxide in BI waste liquid, and it has the following disadvantages: (1) If NO2 gas is used to evaporate the reaction heat, it is necessary to use low-temperature brine to The evaporated NO2 gas is condensed and returned to the oxidation reactor, which not only results in high investment in equipment, but also poor cooling effect; (2) If a partition heat exchanger is used, due to the reaction temperature Butadipic acid is easy to crystallize and adhere to the heat exchange wall surface, which affects the heat exchange effect, and the mechanical method for removing crystallization on the heat exchange wall surface described in the patent is not convenient and reliable. Once the reaction heat cannot be taken away in time, the temperature in the reactor will When the content of HNO3 is so high, the reaction will be extremely violent, and it is easy to cause explosion hazard

[0016] None of the above patents have well solved the problem of recycling and processing of BI waste liquid and DBA waste liquid generated in the production process of adipic acid