METHOD FOR SEPARATING AND PURIFYING P-DICHLOROBENZENE

WIPO Patent Application WO/2016/008175

A1

Provided is a high-purity, high-yield, low-energy consumption and pollution-free method for separating and purifying p-dichlorobenzene, which mainly includes solventing-out precipitation and fractional crystallization steps, wherein the solventing-out precipitation is as follows: putting a p-dichlorobenzene mixture in an ethanol solution, then adding distilled water and controlling the temperature at 5°C-8°C, and standing to obtain p-dichlorobenzene with a purity of 80%-88%; and then fractionally crystallizing (i.e. two-stage and six-section melt crystallizing and refining) the p-dichlorobenzene with the above-mentioned concentration to obtain the p-dichlorobenzene product with a purity of more than 99.9% and a yield of more than 90%. The composite separation and purification method uses ethanol as a main solvent and water as a precipitation agent, and is low in solvent costs, free from pollution, mild in process conditions, and convenient in operation; and in each step of the fractional crystallization process, a DCS system is used to realize the continuous production, reduce the sublimation and loss of the raw material, and then improve the handling capacity and product quality.

SHE DAOCAI (CN)
XU XIAOLIANG (CN)
ZHANG JIANYU (CN)

PCT/CN2014/083272

January 21, 2016

July 30, 2014

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JIANGSU LONGCHANG CHEMICAL CO (CN)

C07C17/392; C07C25/08

CN1259506A	2000-07-12
CN102838448A	2012-12-26
CN102675039A	2012-09-19
CN101580454A	2009-11-18

BEIJING YIGE INTELLECTUAL PROPERTY AGENT LTD (GENERAL PARTNERSHIP) (CN)
北京一格知识产权代理事务所(普通合伙) (CN)

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