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A method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization

A suspension melting crystallization, chlorobromobenzene technology, applied in chemical instruments and methods, organic chemistry, halogenated hydrocarbon preparation and other directions, can solve problems such as poor separation effect, and achieve the effects of cost saving, less environmental pollution, and reduced energy consumption

Active Publication Date: 2021-11-02
兰升生物科技集团股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Aiming at the poor separation effect of existing methods for separating p-chlorobromobenzene and o-chlorobromobenzene, the present invention provides a method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization method:

[0027] Step 1. Ultrasonic disperse the solid-liquid mixture of o-chlorobromobenzene and p-chlorobromobenzene with a p-chlorobromobenzene content of 50% for 30 minutes to obtain a dispersion; add the dispersion to a melting crystallizer, heat to 60°C, get mixed melt;

[0028] Step 2, cooling the mixed molten liquid to 55°C and maintaining it for 30 minutes, then cooling to -2°C at a cooling rate of 0.2°C / min, and growing crystals for 2 hours to obtain crude crystals of p-chlorobromobenzene;

[0029] Step 3. The crude p-chlorobromobenzene crystals are heated up to 4°C at a heating rate of 0.3°C / min, sweated, and maintained for 1.5h to obtain pure p-chlorobromobenzene crystals, which are then suction filtered, washed with water, and dried to obtain p-chlorobromobenzene For bromobenzene products, the discharged crystallization mother liquor is collected and...

Embodiment 2

[0031] A method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization method:

[0032] Step 1. Ultrasonic disperse the solid-liquid mixture of o-chlorobromobenzene and p-chlorobromobenzene with a p-chlorobromobenzene content of 50% for 30 minutes to obtain a dispersion; add the dispersion to a melting crystallizer, heat to 60°C, get mixed melt;

[0033] Step 2: Cool down the mixed molten liquid to 55°C, maintain it for 30min, then cool down to -2°C at a cooling rate of 0.2°C / min, grow the crystal for 2h, suction filter, wash with water, and dry to obtain p-chlorobromobenzene product, The discharged crystallization mother liquor is collected and mixed for recycling. The yield of p-chlorobromobenzene is 66.1%, and the purity is 99.54%.

Embodiment 3

[0035] A method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization method:

[0036] Step 1. Ultrasonic disperse the solid-liquid mixture of o-chlorobromobenzene and p-chlorobromobenzene with a p-chlorobromobenzene content of 50% for 35 minutes to obtain a dispersion; add the dispersion to a melting crystallizer, heat to 75°C, get mixed melt;

[0037] Step 2. Cool the mixed molten liquid to -10°C at a cooling rate of 0.5°C / min, grow crystals for 6 hours, suction filter, wash with water, and dry to obtain p-chlorobromobenzene products, collect and mix the discharged crystallization mother liquor, and circulate use. The yield of p-chlorobromobenzene is 55.4%, and the purity is 99.04%.

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Abstract

The invention provides a method for separating p-chlorobromobenzene and o-chlorobromobenzene by a suspension melting crystallization method, comprising the following steps: ultrasonically dispersing the solid-liquid mixture of o-chlorobromobenzene and p-chlorobromobenzene for 25-35 minutes to obtain a dispersion; Add the dispersion into a melting crystallizer, heat it to 60-75°C to obtain a mixed melt; cool the mixed melt to -10-20°C at a cooling rate of 0.05-0.5°C / min, and grow crystals for 1 ‑6h, filtered with suction, washed, and dried to obtain p-chlorobromobenzene. The separation method of p-chlorobromobenzene and o-chlorobromobenzene provided by the present invention realizes the separation of p-chlorobromobenzene and o-chlorobromobenzene isomers by designing a reasonable crystallization process route and controlling the crystallization process conditions, and by controlling the temperature drop The speed and crystal growth temperature avoid the problems of serious mother liquor occlusion and low product purity in the crystallization process of the general melt crystallization method. The purity of p-chlorobromobenzene can reach more than 99%, and the single-pass yield can reach up to 66.1%.

Description

technical field [0001] The invention relates to the technical field of chemical separation and purification, in particular to a method for separating p-chlorobromobenzene and o-chlorobromobenzene by suspension melting crystallization. Background technique [0002] p-Chlorobromobenzene, also known as 4-chlorobromobenzene, is an important organic chemical raw material, mainly used as a solvent, and an intermediate in pharmaceutical and chemical synthesis. p-Chlorobromobenzene can be mainly used to prepare pesticide fungicides boscalid intermediates, bepotastine intermediates, and as an important raw material for carbsamine maleate, which plays a very important role in the chemical industry. The preparation of p-chlorobromobenzene is mainly by heating bromobenzene and iron powder to 80°C, adding bromine dropwise, and reacting at 90-100°C for 2.5h, and the crude product is obtained by rectification or ethanol recrystallization. However, during the preparation of p-bromochlorobe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C25/02C07C17/392
CPCC07C17/392C07C25/02
Inventor 孙华刘琼刘宝树郭庆春
Owner 兰升生物科技集团股份有限公司