Method and device for synthesizing chloromethane

Abstract

The invention provides a method and a device for synthesizing chloromethane. The method comprises the following steps of: introducing gaseous hydrogen chloride, a preheated hydrochloric acid solution and preheated gaseous methanol as raw materials into a first reaction kettle for a synthesis reaction, and in the reaction process, adjusting the proportion of the hydrochloric acid solution in the raw materials and / or the preheating temperature of the hydrochloric acid solution and / or the preheating temperature of the gaseous methanol according to the reaction temperature in the first reaction kettle; and adding a hydrochloric acid solution into a second reaction kettle, introducing a mixed gas of chloromethane, hydrogen chloride and methanol at an outlet of the first reaction kettle into the second reaction kettle, and introducing liquid methanol for a synthesis reaction. The method does not need to additionally consume energy for heating or cooling, and greatly saves energy. Meanwhile, the double kettles are connected in series for continuous reaction, so that the high conversion rate of the raw materials is ensured. Moreover, waste acid is basically not generated, and the pressure of treating waste acid in a rear-end system is reduced.

Description

technical field [0001] The invention relates to the technical field of preparing methane chloride, in particular to a method and device for synthesizing methyl chloride. Background technique [0002] Chloromethane is an important raw material in the organic synthesis industry, and is mainly used to produce methyl green silane, a raw material for organic silicon compounds. Its synthesis process has been continuously developed in the past 30 years. At present, the mainstream development process in China mainly includes liquid-phase catalytic method and gas-solid-phase catalytic method. However, regardless of the gas-phase method or the liquid-phase method, the reaction between methanol and hydrogen chloride will generate impurity dimethyl ether and the remaining unreacted hydrogen chloride gas. Therefore, it is usually necessary to wash with water, wash with alkali, and finally dry with concentrated sulfuric acid. Dehydration and removal of dimethyl ether and other devices wi...

AI Technical Summary

Problems solved by technology

However, regardless of the gas-phase method or the liquid-phase method, the reaction between methanol and hydrogen chloride will generate impurity dimethyl ether and the remaining unreacted hydrogen chloride gas. Therefore, it is usually necessary to wash with water, wash with alkali, and finally dry with concentrated sulfuric acid. Dehydration and removal of dimethyl ether and other devices will produce a large amount of low-concentration hydrochloric acid and alkali-containing waste liquid

At the same time, in the process of using methanol and hydrogen chloride to synthesize methyl chloride, it is necessary to continuously heat or cool the raw materials, thereby consuming a large amount of energy

It can be seen that the existing process for producing methyl chloride has many problems such as long process, numerous auxiliary materials, many by-products or three wastes, and high energy consumption.

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