Preparation method of tetramethyl biphenyl

A technology of tetramethylbiphenyl and halogenated o-xylene, which is applied in the field of preparation of tetramethylbiphenyl, can solve the problems of difficult reaction control, increased operating environment requirements, violent reaction and the like, and achieves mild and controllable reaction conditions , Simplified production process, mild and controllable conditions

Active Publication Date: 2013-05-08
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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Problems solved by technology

[0005] The existing synthesis technology of tetramethylbiphenyl mainly uses halogenated o-xylene as raw material for collective name, and halogenated o-xylene is obtained by substituting o-xylene, which increases the reaction cost and reaction process to a certain extent. , and the separation of halogenated o-xylene is difficult, and the industrial cost is relatively high
[0007] The Chinese patent with the application number CN200410089450 and the Chinese patent with the application number CN200780035615 both disclose the coupling of halogenated o-xylene and halogenated o-xylene Grignard reagent under the catalysis of a transition metal compound

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  • Preparation method of tetramethyl biphenyl
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  • Preparation method of tetramethyl biphenyl

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preparation example Construction

[0036] The invention provides a preparation method of tetramethylbiphenyl, comprising: A) mixing halogenated o-xylene, metal magnesium, iodine, ether and a transition metal catalyst to react to obtain tetramethylbiphenyl; The molar ratio of ether to magnesium metal is (0.5~3):1.

[0037] Wherein, the halogenated o-xylene is the halogenated o-xylene well known to those skilled in the art, it can be 3-halogenated o-xylene or 4-halogenated o-xylene, or a mixture of both, There are no particular restrictions. The halogen substituents in the halogenated o-xylene in the present invention can be chlorine or bromine, and there is no special limitation.

[0038] The metal magnesium can be metal magnesium well-known to those skilled in the art, and can be magnesium powder, magnesium shavings or magnesium strips, and there is no special limitation. The amount of the magnesium metal is any amount well known to those skilled in the art to maintain the reaction system in a liquid state af...

Embodiment 1

[0062] Replace the air in the 25ml reaction flask equipped with a reflux condenser with nitrogen, and add 0.37g (0.0154mol) magnesium powder, 10ml 3-chloro-o-xylene, 0.01g (3.6 ×10 -6 mol) of iodine and 1.41ml (0.0174mol) of anhydrous THF, stirred and heated to 110°C, the magnesium powder disappeared after 10 hours of reaction, the reaction mixture was cooled to 60°C, and 0.123g (7.7×10 -4 mol) anhydrous ferric chloride, continue to stir and react for 12h, lower the reaction system to room temperature, add 20ml of saturated ammonium chloride solution, stir for 30min, separate the water layer, and analyze the organic layer by gas chromatography to obtain 2,2′,3, 3'-Tetramethylbiphenyl, the yield is 50%, and its gas chromatogram is as follows figure 1 Shown, wherein, A is 3-chloro o-xylene, figure 2 It is the gas chromatogram of the standard sample of 2,2′,3,3′-tetramethylbiphenyl.

Embodiment 2

[0064] Replace the air in a 25ml reaction flask equipped with a reflux condenser with nitrogen, and add 0.37g (0.0154mol) of magnesium powder, 10ml of 4-chloro-o-xylene, 0.01g (3.6 ×10 -6 mol) of iodine and 1.41ml (0.0174mol) of anhydrous THF, stirred and heated to 110°C, the magnesium powder disappeared after 10 hours of reaction, the reaction mixture was cooled to 60°C, and 0.123g (7.7×10 -4 mol) anhydrous ferric chloride, continue to stir and react for 12h, lower the reaction system to room temperature, add 20ml of saturated ammonium chloride solution, stir for 30min, separate the water layer, and analyze the organic layer by gas chromatography to obtain 3,3′,4, 4'-Tetramethylbiphenyl, the yield is 52%.

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Abstract

The invention provides a preparation method of tetramethyl biphenyl, which comprises the following steps: mixing halogenated o-xylene, magnesium metal, iodine, ether and transition metal catalyst, and reacting to obtain the tetramethyl biphenyl, wherein the mol ratio of ether to magnesium metal is (0.5-3):1. Compared with the prior art of synthesizing tetramethyl biphenyl from halogenated o-xylene, the invention has the following advantages: by using the raw material halogenated o-xylene as the solvent, the preparation of the format reagent and the coupling reaction are carried out in the initial raw material, so that the addition of abundant anhydrous solvent as the reaction medium is not needed, thereby lowering the reaction cost and simplifying the production technique; the magnesium metal is directly added into the halogenated o-xylene to obtain the format reagent, so the process is simple and the conditions are mild and controllable; and the raw material, the concentration of which in the reaction system is high, is used as the solvent and participates in the oxidation-reduction process in the coupling reaction, no oxidizer is needed, so the reaction conditions are mild and controllable.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, in particular to a preparation method of tetramethylbiphenyl. Background technique [0002] As a high-performance polymer, polyimide has high temperature resistance, solvent resistance, radiation resistance, good mechanical properties and dielectric properties, and the thermal decomposition temperature of biphenyl polyimide can reach 600 ° C. One of the varieties with the highest thermal stability in the material, it has broad application prospects in the fields of mechanical electronics, aerospace, large motors, turbine bearings, heat-resistant filter materials, etc., but its application is limited due to its high preparation cost. [0003] The key monomer for preparing biphenyl polyimide is biphenyl tetracarboxylic dianhydride, and the synthesis cost of this monomer determines the cost of polyimide to a large extent. Therefore, the pursuit of low-cost polyimide An important way to re...

Claims

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Application Information

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IPC IPC(8): C07C15/14C07C1/26
Inventor 康传清吴强高连勋金日哲丁金英邱雪鹏
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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