Separating and purifying method for tetramethyl biphenyl isomer mixture

A technology of isomer mixture and tetramethylbiphenyl is applied in the field of separation and purification of tetramethylbiphenyl isomer mixture, which can solve the difficulty of separation and purification, high cost, and difficulty of separation and purification of biphenyltetracarboxylic dianhydride mixture and other problems, to achieve the effect of simple process, easy control and good separation effect

Active Publication Date: 2014-12-10
衍天(苏州)新能源科技有限公司
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But above-mentioned various preparation tetramethylbiphenyls required pure monohalogenated o-xylenes are difficult to obtain, and this is because in the process of preparing halogenated o-xylenes by o-xylene, simultaneously generate 3-halogenated o-xylenes and 4 -The mixture of two isomers of halogenated o-xylene, because the boiling points of the two are very close, it is difficult to separate and purify, as reported by Changchun Yinghua of Chinese Academy of Sciences 3 As a catalyst, monochlorinated o-xylene is prepared from chlorine gas and o-xylene, wherein the ratio of 3-chloro-o-xylene and 4-chloro-o-xylene is 45:55
According to U.S. Patent No. 5,683,553, to separate out 3-chloro-o-xylene and 4-chloro-o-xylene with a purity of 99%, a rectification column with 250 theoretical plates is required to obtain pure 3-halogenated The cost of ortho-xylene or 4-halogenated ortho-xylene is very high, which in turn drives up the cost of biphenyl dianhydride
The three kinds of tetramethylbiphenyl mixtures generated by the coupling of mixed halogenated o-xylenes will be directly oxidized without separation and purification to generate three kinds of biphenyltetracarboxylic dianhydride mixtures, while the separation and purification of three kinds of biphenyltetracarboxylic dianhydrides Formic dianhydride mixtures are more difficult

Method used

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  • Separating and purifying method for tetramethyl biphenyl isomer mixture
  • Separating and purifying method for tetramethyl biphenyl isomer mixture
  • Separating and purifying method for tetramethyl biphenyl isomer mixture

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Embodiment 1

[0014] The preparation of mixed tetramethylbiphenyl refers to the preparation method of biphenyl compound in J. Org. Chem., 51, No.14 (1986) 2627-2637, the reaction conditions: mixed chlorinated o-xylene (3-chloro-o-diphenyl Toluene:4-chloro-o-xylene=45:55), anhydrous NiCl 2 , triphenylphosphine, reducing agent zinc powder and anhydrous N,N-dimethylacetamide molar ratio=100:5:35:8:300, under inert atmosphere, 80 o C was reacted for 5 hours. After the reaction, the inorganic matter was filtered off, and the product was extracted with chloroform. After evaporating the chloroform, the crude product of mixed tetramethylbiphenyl was obtained, and the yield was 96%.

Embodiment 2

[0016] 513 g of mixed tetramethylbiphenyl was distilled through a fractionation column with 10 theoretical plates under normal pressure (101KPa). The conditions of each fraction are as follows:

[0017]

[0018] The purity is determined by gas chromatography. The components of mixed tetramethylbiphenyl are: light component impurities 0.50%, 2,2',3,3'-tetramethylbiphenyl 20.80%, 2,3',3,4 '-tetramethylbiphenyl 55.20%, 3,3', 4,4'-tetramethylbiphenyl method 23.50%.

Embodiment 3

[0020] Mix 1000 g of tetramethylbiphenyl, pass through a distillation column with a theoretical plate number of 35, and distill at a pressure of 20.5KPa, less than 206 o C light component impurity 4.5g; at 206-212 o C obtained 2,2',3,3'-tetramethylbiphenyl 212 g with a purity of 98.5%; at 220-227 o C obtained 553 g of 2,3’,3,4’-tetramethylbiphenyl with a purity of 98.3%; 235-245 o C obtained 230 g of 3,3’, 4,4’-tetramethylbiphenyl with a purity of 98.7%.

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Abstract

The invention discloses a separating and purifying method for tetramethyl biphenyl isomer mixture. Halogenated o-xylene is coupled to generate 2, 2', 3, 3'-tetramethyl biphenyl, 2, 3', 3, 4'-tetramethyl biphenyl and 3, 3', 4, 4'-tetramethyl biphenyl, and purifiers of the tetramethyl biphenyl isomers can be respectively obtained through a rectification method; the rectification conditions are that rectifying columns with more than one theoretical plate are used; fractions with the temperature of 100-350 DEG C are collected under the pressure range of 1-101KPa; the 2, 2', 3, 3'-tetramethyl biphenyl, the 2, 3', 3, 4'-tetramethyl biphenyl and the 3, 3', 4, 4'-tetramethyl biphenyl which have the purity of 90-99.5 percent can be obtained by rectifying the mixed tetramethyl biphenyl.

Description

technical field [0001] The invention relates to the technical field of separation and purification of isomers of organic compounds, in particular to a method for separation and purification of a tetramethylbiphenyl isomer mixture. Background technique [0002] There are three main isomers of biphenyltetracarboxylic dianhydride, namely 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride, 2, 3', 3, 4'-biphenyltetracarboxylic dianhydride and 2, 2' , 3,3'-biphenyltetraacid dianhydride. In particular, the polymers synthesized from 2,3'3,4'-biphenyltetraacid dianhydride with asymmetric structure have a high degree of unity of processability and high performance, and have attracted extensive attention from experts in the field of polymer composite materials. The current method for preparing 2, 3', 3, 4'-biphenyltetraacid dianhydride is extremely costly, so its price is about 15-20 times that of the other two isomer dianhydrides. [0003] Patents US7893306, US7425650, JP61-22045, CN2...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): C07C15/14C07C7/04
Inventor高昌录李刚孙秀花
Owner衍天(苏州)新能源科技有限公司