Adding process of reaction protection agent

Abstract

The invention discloses an adding process of a reaction protection agent. The adding process includes the steps of 1), adding fresh octanol into a reactor; 2), after the temperature of the reactor is reduced, starting stirring and adding phthalic anhydride until the adding is finished, and continuing stirring; 3), adding tristearyl phosphite, and sufficiently dissolving the tristearyl phosphite; 4), adding reaction materials including the phthalic anhydride and the octanol into the reactor according to the mole ratio of 1:(1.8-2.1), and performing esterification reaction until the reaction is finished. The adding process has the advantages that oxidization caused by nitrogen purity or equipment leakage and the like can be remedied, the color of semi-finished products can be reduced favorably, the quality of recycled alcohol can be improved, operation stability is achieved, product yield is increased, and small single-batch fluctuation is achieved.

Description

technical field [0001] The invention relates to chemical reaction technology, in particular to the technical field of esterification reaction. Specifically, it shows a process for adding a reaction protecting agent. Background technique [0002] The esterification reaction is a common production process in the chemical technology field. The steps are generally: the reaction materials phthalic anhydride and octanol are added to the reactor at a ratio of 1:1.8--2.1 (molar ratio); [0003] However, since the reaction temperature is as high as 220°C during the production of dop, the ester liquid is easily oxidized to form chromosomes in contact with a large amount of air. When the raw material is good, the temperature of the feed liquid is as high as 90--100°C, and the color of the crude ester increases by 10#--15 #, in order to avoid the contact between the acidic ester liquid and the air, the commonly used methods are: control the airtightness of the equipment, and replace the...

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Problems solved by technology

[0003] However, since the reaction temperature is as high as 220°C during the production of dop, the ester liquid is easily oxidized to form chromosomes in contact with a large amount of air. When the raw material is good, the temperature of the feed liquid is as high as 90--100°C, and the color of the crude ester increases by 10#--15 #, in order to avoid the contact between the acidic ester liquid and the air, the commonly used methods are: control the airtightness of the equipment, and replace the air in the reactor with nitrogen. Chromaticity of a single batch of products; resulting in unqualified products