Preparation method of phosphite ester by using dividing wall tower reaction rectification technique

Abstract

The present invention discloses a preparation method of phosphite ester by using a dividing wall tower reaction rectification technique, comprising the following steps: selecting phosphorous acid, a reactant alcohol and a water carrying agent as raw materials, the dosage of the reactant alcohol is 2 to 9 times the demand of the reaction; adding the raw materials into a reactor which is additionally provided with a dividing wall-typed rectifying tower for reaction, the reaction temperature is between 80 to 160 DEG C, leading cooling water into the overhead condenser timely, distilling off the lowest binary azeotrope formed by the water of the reaction and the reactant alcohol or the lowest ternary azeotrope formed by the water of the reaction, the reactant alcohol and the water carrying agent from the tower top, leading the distillate into a stratifying device after condensation, leading the oil phase into the side communicated with the reactor and leading the aqueous phase into the other side; stopping the backflow when the amount of the water in the aqueous phase reaches the preconcerted amount, distilling off the excessive reactant alcohol; stopping the heat when no distillate appears on the tower top, and the product let out from the tower bottom is phosphite ester. The invention has fast reaction speed, high product purity and fewer by-products.

Description

Technical field [0001] The invention belongs to the technical field of fine chemical additives and intermediates, and relates to an improved preparation method of phosphites. Background technique [0002] At present, the production of phosphites in the field of fine chemical additives and intermediates uses volatile phosphorus trichloride and corresponding alcohols as raw materials. Many processes also use toluene as solvents at 50-70°C. Reaction at low temperature. When the alcohol is excessive, the phosphite triester and a large amount of hydrogen chloride and the by-product chloroalkane are obtained. When the amount of alcohol is insufficient and the phosphite triester can be decomposed into the phosphite diester and the corresponding chloroalkane in the presence of hydrogen chloride, after the reaction is completed, The hydrogen chloride and chloroalkane produced by the reaction are distilled off, and then the corresponding phosphite is obtained by vacuum distillation, and h...

AI Technical Summary

Problems solved by technology

However, phosphorus trichloride is volatile, highly toxic, and the operating environment is poor. The key is that there are many by-products. In order to reduce side reactions, it is often necessary to add