Preparation method of dichloro propanol from glycerin

A technology of dichloropropanol and glycerin, which is applied in the chemical industry, can solve problems such as low reaction efficiency, low equipment utilization rate, and easy coke formation, and achieve the effects of reduced energy consumption, increased equipment utilization rate, and increased reaction rate

Active Publication Date: 2009-07-08
溧阳常大技术转移中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Such a process has a mature process and sufficient sources of raw material propylene, which can meet the huge market demand, but this process route also has serious disadvantages: ①High temperature chlorination, high energy consumption, and many side reactions; ②The reaction process is prone to coking, The equipment needs to be shut down frequently to clean the coke; ③The utilization rate of chlorine gas in the reaction process is only about 38%, and the concentration of the product dichloropropanol is generally controlled at 4%, so a very large amount of chlorine-containing wastewater is produced in the production process
But this process still has high energy consumption and low utilization rate of equipment
[0018] Generally speaking, the existing technology is all to react in the bubble tank (tower) or stirred tank, and the HCl concentration is low in the reaction system, and the reaction rate is low.
Reactor form determines low reaction efficiency and high energy consumption
Moreover, the low-efficiency reaction can easily cause the formation of high boiling substances and reduce the selectivity of the reaction.

Method used

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  • Preparation method of dichloro propanol from glycerin
  • Preparation method of dichloro propanol from glycerin
  • Preparation method of dichloro propanol from glycerin

Examples

Experimental program
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Effect test

example 1

[0040] Example 1. Glycerol (95% industrial product) is mixed with HCl (by PCl 3 with H 2 O is produced by 1:3.5 reaction) at 0.6mol / h. Pumped in via pre-mixing figure 1In the reaction system shown, the temperature of the oil bath in the tubular reactor is 105°C, which is adjusted by the outlet flow regulating valve 5, so that the residence time of the material in the tubular reactor is 6h. Gas chromatographic analysis through the sampling valve 4 shows that the conversion rate of glycerin is 93.6%, the generation rate of monochloropropanediol is 84.4%, and the generation rate of dichloropropanol is 8.9%. NaOH standardizes the acid concentration of the reaction solution to 0.49mol / L.

[0041] The reaction liquid flowing out of the tubular reactor directly enters the HCl bubble column reactor, the reaction temperature is controlled at 108°C, the feed rate of HCl is 1.2mol / h, and the flow rate of the material in the bubble reactor is controlled through the outlet valve 12. Th...

example 2

[0043] Example 2. Changing the residence time of materials in the bubble reactor. Put industrial glycerin (95%) at 0.6 mol / h (which contains 2% acetic acid as a catalyst) and HCl at 0.6 mol / h through pre-mixed pumping figure 1 In the reaction system shown, the temperature of the oil bath in the tubular reactor is 100°C, and the outlet pressure and flow rate are adjusted, and the residence time of the material in the tubular reactor is 6h.

[0044] Control the temperature of the bubbling reactor to 110°C, adjust the outlet flow rate, so that the residence time of the material in the bubbling reactor is 7h, the amount of HCl introduced is 0.8mol / h, and the generated azeotrope is condensed with the tail gas. Liquid separation and collection.

[0045] Within 5 hours of steady-state operation, 295 g (3 mol) of glycerol was fed, 9 mol of HCl was fed, and glycerol was completely converted. 198 g of condensate (including 39.1 g of dichloropropanol, 62 g of HCl, 91.8 g of water, and ...

example 3

[0046] Example 3. Changing the residence time of the material in the tubular reactor. Industrial glycerin (95%) is fed with 1.0mol / h (containing 2% acetic acid), HCl 1.0mol / h, and the temperature of the tubular reactor is controlled at 105°C. The residence time of the material in the tubular reactor is about 3.5h. The conversion rate of glycerol at the outlet of the formula reactor was 81.6%, the production rate of monochloropropanediol was 79.2%, and the production rate of dichloropropanol was 2.0%. The acid value of NaOH is 1.4mol / L.

[0047] The reaction liquid in the tubular reactor enters the HCl bubbling reactor to continue the reaction, the HCl feed rate is 2mol / h, the temperature of the bubbling reactor is controlled at 110°C, and the residence time is 10h.

[0048] Within 5 hours of steady-state operation, 5 mol of glycerol and 15 mol of HCl were fed, and glycerol was completely converted. Condensate 257.2g of condensate from the tail gas of the bubble reactor, whic...

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Abstract

The invention relates to a method for preparing dichloropropanol from glycerol. Firstly, glycerin, HCl and carboxylic acid catalyst are added into a mixer, continuously pressed into a tubular reactor for chlorination reaction, and the glycerol is rapidly transformed through the reaction in the tubular reactor. The reactant then enters the HCl bubbling tank to continue the reaction. Here, the water generated by the reaction forms an azeotrope with dichloropropanol, HCl and some catalysts and evaporates from the upper part of the bubbling kettle. The product dichloropropanol is obtained at the top of the distillation tower, and the bottom liquid of the rectification tower is sent to the circulation reaction. The reactor combination method proposed by the present invention is designed according to the characteristics of the different stages of the reaction, so that the reaction rate is increased, the utilization rate of the equipment is improved, and the glycerol is completely converted within 12 to 16 hours, and the yield of dichloropropanol can be greater than 90%. , HCl utilization increased to over 70%.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a preparation method of a propylene oxide intermediate. More specifically a process for the preparation of dichloropropanol from glycerol. Background technique [0002] Dichloropropanol is a key intermediate in the production of epichlorohydrin, and its annual output is close to 2 million tons. The main method of producing dichloropropanol worldwide is based on the high-temperature chlorination of propylene developed by the American shell company in 1948. The preparation process includes: [0003] [0004] [0005] Such a process has a mature process and sufficient sources of raw material propylene, which can meet the huge market demand, but this process route also has serious disadvantages: ①High temperature chlorination, high energy consumption, and many side reactions; ②The reaction process is prone to coking, The equipment needs to be shut down frequently to clean the c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C29/62C07C29/74C07C31/42C07C31/34B01J31/04
Inventor 单玉华韩蕾蕾徐正华李明时朱建军
Owner 溧阳常大技术转移中心有限公司
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