Continuous production method of ethyl chloride

Abstract

The invention discloses a continuous production method of ethyl chloride. The method comprises the following steps: (1) mixing: preheating ethanol to 50-100 DEG C by a preheater, sending the ethanol into a mixing tube, sufficiently mixing with hydrogen chloride gas, and continuously introducing the mixture into a reaction kettle; (2) reaction: preparing a zinc chloride water solution in a reaction kettle, carrying out reaction on the chlorine hydride and ethanol at 100-160 DEG C under the pressure of 0.01-0.2 MPa under the action of zinc chloride to remove water, condensing the gas-phase system by a condenser to obtain a gas-phase ethyl chloride crude product and a condensate, and returning the condensate to the reaction kettle; and (3) refinement: sequentially passing the ethyl chloride crude product through a two-stage water absorption tower, a two-stage sulfuric acid drying tower and a sulfuric acid demister, and liquefying by compression to obtain the ethyl chloride finished product. The temperature of the ethanol is enhanced before the reaction, and the chlorine hydride and ethanol are mixed, thereby enhancing the reaction rate; and the method has the advantages of high conversion rate of ethanol, low productive energy consumption and high product purity.

Description

technical field [0001] The invention belongs to the field of chemical production, and in particular relates to a continuous production method of ethyl chloride. Background technique [0002] As an alkylating agent, ethyl chloride is widely used in the synthesis of pesticides, dyes, medicines and their intermediates. There are three synthesis methods of ethyl chloride: the addition of ethylene and hydrogen chloride, the chlorination of ethane, and the synthesis by the reaction of hydrochloric acid and ethanol; the first method uses ethylene, because ethylene has high requirements for transportation and storage equipment, and the reaction Harsh conditions require high temperature and high pressure, so industrialization is limited; the second method, the ethane chlorination method, has mild reaction conditions, but there are many by-products. While the chlorination reaction generates ethyl chloride, it also generates dichloroethane , trichloroethane, so the product separation ...

AI Technical Summary

Problems solved by technology

There are three synthesis methods of ethyl chloride: the addition of ethylene and hydrogen chloride, the chlorination of ethane, and the synthesis by the reaction of hydrochloric acid and ethanol; the first method uses ethylene, because ethylene has high requirements for transportation and storage equipment, and the reaction Harsh conditions require high temperature and high pressure, so industrialization is limited; the second method, the ethane chlorination method, has mild reaction conditions, but there are many by-products. While the chlorination reaction generates ethyl chloride, it also generates dichloroethane , trichloroethane, so the product separation and purification system is relatively complicated, and the product yield is low; the third method is easy to operate, adopts enamel equipment, and the reaction conditions are mild. After refining, high-purity ethyl chloride can be obtained; The third synthesis method, hydrochloric acid and ethanol synthesize ethyl chloride at a reaction temperature of 110-145 ° C and anhydrous zinc chloride as a catalyst. During the reaction, hydrochloric acid is brought into the water in the reaction system, and the reactor needs to be steam When the water is steamed out, 3.5 tons of steam are consumed for producing 1 ton of ethyl chloride. In addition, the amount of waste water produced is relatively large, and each ton of product produces 2.05 tons of ethanol-containing waste water.

[0003] The synthesis method of hydrochloric acid and ethanol has the following disadvantages: 1) the ethanol conversion rate is on the low side, and about 10% of ethanol will be brought into the crude product ethyl chloride, and enter the post-treatment refining process together; 2) use hydrochloric acid to participate in the reaction, bringing Enter a large amount of water, and react simultaneously to produce water, and these waters all need to be steamed out from reaction system, and this part water contains 5~10% ethanol and 10~20% hydrogen chloride, needs further rectification; 3) adopt hydrochloric acid to participate in reaction, reaction The system is unstable, continuous production cannot be realized, and the batch reaction is mainly tank-type, and the production efficiency is low

However, high-temperature reactions are used in the above processes, and subsequent purification requires the use of rectification devices. At the same time, post-treatment still requires alkali absorption (that is, cooling, condensing and liquefaction through indirect heat exchange with cooling water in the condenser 2, and then chromatographic separation) , pump (discharge) the lower layer hydrochloric acid ethanol solution of the chromatography and return to the special-purpose ethyl chloride reactor 1 for recycling. Alkanes semi-finished product storage tank 3), increased aftertreatment cost, and adopt a large amount of hydrochloric acid in the reaction, make the water amount that raw material introduces increase, increased the energy consumption of mother liquor concentration

At the same time, the acidic water treated by it is directly discharged as wastewater treatment, which increases post-treatment costs and raw material consumption

Images