Solvent-free esterification-distillation integrated process

Abstract

The invention discloses a solvent-free esterification-distillation integrated process. In the process, a high feeding tank, an esterification kettle, a storage tank and a thin-film evaporator are connected in series; aliphatic alcohol and acid raw materials which is subjected to pretreatment is fed into the circulating esterification kettle with a catalyst fixed bed from the high tank; an esterification is accomplished by means of circulating esterification, and water generated in the reaction is evaporated out by means of constantly vacuumizing to promote the esterification to advance in a forward direction; after the esterification is accomplished, the coarse product is delivered by the circulating pump to the thin-film evaporator from the nitrogen protected storage tank; unreacted excessive organic materials with small molecular weights are evaporated out; and through refining, the pure product is obtained. Compared with the conventional process, the process disclosed by the invention has the advantages that: solvent is not needed in the whole process; excessive organic raw materials with small molecular weights can be recycled; and the process is an energy-saving, emission-reducing and environment-friendly esterification synthesis process.

Description

Technical field: [0001] The invention relates to a solvent-free esterification reaction-distillation integration process, which is applied to the synthesis of aliphatic alkyd esters, and has the characteristics of energy saving, emission reduction, green and pollution-free. Background technique: [0002] The esterification reaction generally consists of aliphatic alcohol and aliphatic carboxylic acid in the presence of a catalyst, dehydration reaction to generate aliphatic ester. The traditional esterification process is divided into two types: one is the solvent method, the aliphatic alkyd uses a homogeneous or heterogeneous catalyst, and the esterification reaction is carried out under the condition of a solvent. The solvent can form an azeotrope with water, and the water is continuously removed from the reaction system. It is taken out in the middle, and the reaction is promoted to proceed forward. The solvents that can be used as water-carrying agents include toluene, xy...

AI Technical Summary

Problems solved by technology

There are some shortcomings in the esterification reaction under the condition of solvent. During the process of carrying water, due to the continuous reflux and condensation of the solvent, part of the heat is taken away by heat exchange, which increases energy consumption. At the same time, after the reaction is completed, the solvent must be evaporated. In the process of solvent recovery, there will be some losses. Solvents such as toluene and xylene are expensive, resulting in increased production costs. The use of solvents will pollute the environment, and some solvents are toxic, causing harm to operators. harm

[0003] Another method is the solvent-free method. The solvent-free method is divided into two types. One uses excess organic components in the esterification reaction as water-carrying agents. Usually, the excess organic components are not compatible with water. (such as butanol), which can form an azeotrope with water, or continuously blow organic component vapor (such as methanol) into the reaction system, and the organic component vapor will take away the water generated by the reaction to promote the esterification reaction. This method has higher requirements for esterification raw materials, and its application range is narrower; another method is to vacuumize the reaction system and steam the water generated by the reaction. This method generally requires the use of soluble catalysts in the system, and it is easy to cause The degree of esterification is not high, and the esterification time is long

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