Method for rectifying dimethyl phosphite

Abstract

The invention relates to a method for rectifying dimethyl phosphite. The method comprises the following steps that after raw materials are fully reacted in an esterification reaction kettle, crude ester enters the rectification kettle, a first rectifying tower and a second rectifying tower are arranged at the top of the rectifying kettle, and the first rectifying tower and the second rectifying tower are continuously heated; the first rectifying tower firstly collects low-boiling-point substances in the materials into a low-boiling-point substance storage tank, and tower bottom discharge liquid enters the second rectification tower for further separation; a vacuum unit is started for vacuum concentration, high-purity dimethyl phosphate is collected into a product storage tank, and tower bottom residual liquid is high-boiling-point substances. The technical process is simple, the production time is short, the product purity is high, the yield is high, continuous production can be achieved, the cost is low, the fuel utilization rate is high, emission is basically avoided, the environmental pollution is small, the reaction operation safety is high, the labor intensity is low, the labor efficiency is high, the product quality is good, and industrialization is facilitated.

Description

technical field [0001] The invention belongs to the field of synthesis and preparation of pharmaceutical intermediates, in particular to a rectification method of dimethyl phosphite. Background technique [0002] Dimethyl phosphite, molecular formula C 2 h 7 o 3 P, molecular weight 110.05, appearance is a colorless transparent liquid with a slight fragrance, boiling point is 170°C, relative density is 1.20, soluble in water, easily soluble in most organic solvents such as alcohol and ether. Commonly used as lubricating oil additives, adhesives and some organic synthesis intermediates. It is used in the synthesis of insecticides omethoate, methylthiocyclophos and herbicide glyphosate, etc. It has a wide range of uses. With the continuous expansion of domestic production scale of alkyl ester method glyphosate, the demand for dimethyl phosphite increases sharply. The traditional refining method of batch distillation is facing a severe test. [0003] The synthesis of dime...

AI Technical Summary

Problems solved by technology

The specific methods are: solvent reaction and solvent-free reaction. The specific methods include vapor-liquid reaction, vapor-vapor reaction, discontinuous method, continuous method, etc. Since the reaction is a violent exothermic reaction, the reaction speed is fast, and it is completed in an instant. Discontinuous method operation Frequent, labor-intensive, long production cycle, low equipment utilization, limited production capacity

Due to the complex components of reactants, high boiling point of the mixture, strong corrosiveness, difficult separation, high energy consumption, low processing capacity, and complicated equipment, it is difficult to adapt to large-scale industrial production.