Method for preparing dichlorohydrin by glycerol hydrochlorination

Abstract

The invention provides a method for preparing dichloropropanol from glycerol through hydrochlorination, which comprises the steps as follows: (1) the mixing raw material liquid of activator and the glycerol is poured into an absorption reaction tower from the top thereof, hydrogen chloride is put into the absorption reaction tower from the bottom thereof, the materials at the bottom of the absorption reaction tower are partially sent back to the absorption reaction tower and parts are put into the first stirring vessel of n stirring vessels; (2) the hydrogen chloride is let into the first stirring vessel for carrying out reaction and then reaction solution enters into the second stirring vessel of the n stirring vessels to react with the hydrogen chloride, and the reaction solution reacts with the hydrogen chloride in the n stirring vessels in turn according to the process; (3) the condensate of the gaseous phase mixtures braised out from the tops of the stirring vessels are gaseous phase products and the mother liquor comes out from the nth stirring vessel is aqueous phase product. The method of the invention is low in investment on equipment, simple in operation and control and high in reaction speed, thus being easy for expanding production with the yield of dichloropropanol per pass higher than 90 percent and the use ratio of the hydrogen chloride higher than 70 percent.

Description

technical field [0001] The present invention relates to a process for the preparation of dichloropropanol. Background technique [0002] At present, the industrial production methods of dichloropropanol mainly use propylene as a raw material for propylene high-temperature chlorination and propylene acetate method. [0003] Among them, more than 90% of dichloropropanol intermediates in the world are produced by high-temperature chlorination of propylene. The process mainly includes two reaction units: high-temperature chlorination of propylene to produce allyl chloride, and hypochlorination of allyl chloride to synthesize dichloropropanol. The reaction formula is: [0004] [0005] The process method is characterized by flexible production process, mature process, stable operation, and can also produce various organic synthesis intermediates. However, there are shortcomings such as serious equipment corrosion, high energy consumption, high chlorine consumption, many by-p...

AI Technical Summary

Problems solved by technology

In addition, a non-volatile catalyst is used, so the amount of catalyst is small, but this process has high energy consumption and low equipment utilization

[0018] The method introduced in patent CN101182283A is to add glycerin and catalyst together into the jet reactor, and the liquid phase circulation pump will extract the glycerin and catalyst from the jet reactor, and then enter the jet reactor from the top of the jet reactor in a jet mode, from The hydrogen chloride gas sucked into the side of the jet reactor fully reacts with the liquid phase material in the reactor, and at the same time, the negative pressure generated by the jet will take out the water, dichloropropanol and hydrogen chloride produced in the reaction in the form of azeotrope, and pass through the condenser The water and dichloropropanol in the azeotrope are condensed as the final product, and the unreacted hydrogen chloride gas is recycled. This process has the characteristics of high raw material utilization rate and fast reaction rate, but the equipment is relatively complicated and difficult to operate.

[0019] In a word, some of the existing dichloropropanol preparation methods have low product yields, some technical equipment is relatively complicated, and the utilization rate of hydrogen chloride is low, so it is not easy to scale up production

Images