Control method for preparing reaction end points of (S)-(+)-epichlorohydrin by chemically splitting dl-epichlorohydrin

Abstract

The invention belongs to a control method for preparing reaction end points of (S)-(+)-epichlorohydrin by chemically splitting racemic epichlorohydrin, and belongs to the field of control of the reaction end points. The method comprises the following steps of in the presence of catalysts, enabling the dl-epichlorohydrin and glacial acetic acid to be subjected to an activating reaction under the condition that air is led, so that reaction liquid is obtained; and controlling the temperature of the reaction liquid to be 20-25 DEG C, slowly and dropwise adding water for a hydolysis reaction, after the water is dropwise added for the first time, performing a heat insulating reaction, then slowly and dropwise adding water for the second time, performing the heat insulating reaction under 20-25 DEG C, and when the hydolysis reaction is performed for 38 hours, detecting the special gravity equivalent of the reaction liquid under the condition of constant temperature of 20 DEG C, wherein detection is performed once every 31 minutes, and when the special gravity equivalent is within the range of 1.095-1.100g / cm<3>, the reaction end points are obtained. The method has the advantages of being convenient and quick in detection, low in cost, reliable in detection result and the like.

Description

technical field [0001] The invention belongs to the field of control of the reaction end point, and specifically relates to a method for controlling the reaction end point of preparing D-epoxychlorohydrin through chemical resolution of mixed-rotation epichlorohydrin. Background technique [0002] The preparation of D-epoxychlorohydrin is prepared by splitting and reacting with mixed-rotary epichlorohydrin (also known as racemic epichlorohydrin), water, acetic acid and catalyst, and the reaction time in the production process is fixed. 44 hours, but in industrial production, it is inevitable that the reaction rate will change due to minor environmental factors, resulting in a deviation in the degree of reaction at the end of the split reaction in 44 hours. The same reaction time is often obtained due to the influence of minor environmental factors. different results. The reaction of mixed-rotational epichlorohydrin exceeds the requirement of resolution (commonly known as ove...

AI Technical Summary

Problems solved by technology

[0003] At present, more than 20 domestic manufacturers use the chemical split method to produce D-epichlorohydrin. Although the gas phase method is used to detect the end point technology in production, it requires tracking and testing of several samples per batch, which is time-consuming and laborious, and the work efficiency is low. At the same time, when the sample is qualified, the 1-hour inspection time often leads to the continuation of the reaction, and the problem of product yield decline still exists; also because of the characteristics of the material liquid, the gas phase instrument is seriously lost or even damaged.

Although the gas phase detection method is mature, the equipment is expensive and the operation is cumbersome, and it is not suitable for the production needs of tracking and monitoring