A method for continuously preparing dichloropropanol with glycerol and hydrochloric acid

Abstract

The object of the invention is to provide a method for synthesizing dichloropropanol with glycerin and hydrochloric acid. After pretreated industrial hydrochloric acid or pretreated industrial by-product hydrochloric acid or reagent hydrochloric acid is mixed with glycerin and catalyst in a batching tank, continuous Put it into a reactor equipped with a fractionation device on the top, continue heating under normal pressure for chlorination reaction, the temperature is controlled at 100-200°C, while continuously performing chlorination reaction, continuously distill the material in the reactor, and the product dichloro Propanol and water are continuously taken out from the reaction system after being condensed into liquid by the condenser; the same pretreatment method of industrial hydrochloric acid and industrial by-product hydrochloric acid of the present invention is to add one or more phosphorus-containing and / or sulfur-containing hydrochloric acid to the hydrochloric acid to be treated. Alkali metal and / or alkaline earth metal salts of inorganic acids, added in an amount of 0.1 to 15% of the weight of the hydrochloric acid to be treated, stirred at a temperature of 0 to 100°C for 0.5 to 15 hours; And the by-product hydrochloric acid provides a good outlet, which is conducive to reducing the production cost of dichloropropanol.

Description

[0001] technical field [0002] The invention belongs to a process for preparing organic chemical products, in particular to a process and a device for continuously preparing dichloropropanol using glycerin and industrial hydrochloric acid as raw materials. Background technique [0003] The process of preparing dichloropropanol from glycerol can be divided into the reaction process of glycerin with HCL gas in the presence of a catalyst (hereinafter referred to as "HCL gas process") and the reaction process of glycerin with HCL in hydrochloric acid in the presence of a catalyst (hereinafter referred to as For "hydrochloric acid water process) two categories. [0004] "HCL gas process" is currently the main reported process. The difference between these processes is only in the catalyst, specific process details and equipment configuration. Their common feature is to promote the equilibrium reaction to the direction of the product by controlling the amount of water in the reac...

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Problems solved by technology

[0004] "HCL gas process" is currently the main reported process. The difference between these processes is only in the catalyst, specific process details and equipment configuration. Their common feature is to promote the equilibrium reaction to the direction of the product by controlling the amount of water in the reaction system. Purpose, this type of process has the following disadvantages: (1) glycerin with a water content of more than 10% cannot be directly used, and this type of glycerin is more common in by-product glycerin. If it is to be used, it must be dehydrated, thus increasing production. Cost; (2) The storage and transportation of raw material HCL gas is inconvenient; (3) Most of them can only use batch batch process, while a few continuous feeding and discharging processes need to operate under pressure and require more equipment and more complicated operations , so whether it is a large equipment investment or production power consumption, and the operation is inconvenient; and for most batch-batch processes, multi-stage series absorption must be used to ensure a high utilization rate of HCL, so The equipment investment is large, and the utilization rate of the equipment is also low; (4) At the operating temperature, the absorption concentration of HCL gas is low, and the reaction speed is slow; (5) Some of these processes use dehydrating agents, so dehydrating agents are added Cost of Consumption and Separation Operating Costs

Among them, the parts of the first seven Chinese patent applications of Solvay Company related to the preparation of dichloropropanol by "hydrochloric acid aqueous process" are similar, only the emphasis is different, and they are the same as the last patent application of Changchun Artificial Resin Factory Co., Ltd. Have respective characteristics, also all have following deficiency: (1) do not make reagent hydrochloric acid, industrial hydrochloric acid and industrial by-product hydrochloric acid distinguish treatment to raw material hydrochloric acid, and according to the experimental result of the present invention, when using these three types of hydrochloric acid respectively as raw material, The results are very different; (2) Both are continuously added to the catalyst along with glycerin and / or hydrochloric acid, so the catalyst consumption is relatively large. Although both of them can recycle part of the catalyst, the consumption is still relatively large and increases Separation of operating costs; (3) No specific automatic control continuous feeding scheme is given, but in industrial production, automatic control of continuous feeding can not only reduce the operating burden of production workers, but also is very important for the stable control of production connections

And the part about the preparation of dichloropropanol in "Journal Articles" is the basis of the present invention, but there are also the following deficiencies: (1) no specific regulations and instructions are made to industrial hydrochloric acid pretreatment additives and pretreatment process schemes; When the by-product hydrochloric acid is used as the chlorinating agent of the present invention, its quality requirements and pretreatment process scheme are not specified and explained; (3) the catalyst for glycerin chlorination is not specified and specified; (4) It is not clear that the catalyst is only added once at the initial feeding; (5) There is no specific plan and description for the automatic control method and device of continuous feeding; (6) There are different production cycles for process parameters and operation content (7) A set of preparation equipment compatible with the process method is not given

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