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Preparation method of tetramethyl biphenyl

A technology of tetramethylbiphenyl and o-xylene, applied in the direction of condensation hydrocarbon production with dehydrocarbons, organic chemistry, etc., can solve the problem of increased reaction cost and reaction process, difficulties in the separation of halogenated o-xylene, post-treatment cumbersome and other issues, to achieve high atom economy, low equipment requirements, and reduce production costs

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
[0009] Publication number is that the Chinese patent of CN101638354 discloses a kind of preparation method of tetramethylbiphenyl, and it uses palladium carbon as catalyst, carries out the coupling of halogenated o-xylene with alcohol as reducing agent to obtain tetramethylbiphenyl, but this The method needs to use a large amount of lye, and the aftertreatment is more loaded down with trivial details, and its reaction process is as follows:

Method used

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

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[0026] The invention provides a preparation method of tetramethyl biphenyl, which comprises: mixing o-xylene, an oxidant, an additive and a metal catalyst, and reacting to obtain tetramethyl biphenyl; the additive is an organic acid and / or an organic Acid anhydride; the oxidant is an inorganic oxidant and / or an organic oxidant containing an oxidizing transition metal cation.

[0027] Wherein, the inorganic oxidant may be an inorganic oxidant well-known to those skilled in the art, and there is no particular limitation, and the organic oxidant containing an oxidizing transition metal cation is a well-known oxidizing transition metal cation known to those skilled in the art The organic oxidizing agent of the metal cation may be used, and is not particularly limited. The oxidant in the present invention is preferably potassium persulfate, sodium persulfate, ammonium persulfate, potassium hydrogen persulfate, sodium hydrogen persulfate, copper acetate, copper nitrate, copper sulfa...

Embodiment 1

[0043] Mix 56.0 mg (0.2 mmol) of palladium acetate, 6.48 g (24 mmol) of potassium persulfate, 6.0 ml (50 mmol) of o-xylene and 1.5 ml (20 mmol) of trifluoroacetic acid, heat to 45 ° C, stir the reaction for 13 h, and then use saturated The acid in the system is neutralized by sodium bicarbonate, and the organic phase is analyzed by gas chromatography, and the conversion rate of o-xylene to tetramethyl biphenyl is 27.3%, of which 3,3′,4,4′-tetramethylbiphenyl , The molar ratio of 2,2',3,3'-tetramethylbiphenyl to 2,3,3',4'-tetramethylbiphenyl is 0.09:1.07:1, such as figure 1 shown, where A is o-xylene, figure 2 Gas chromatogram of mixed tetramethylbiphenyl standard sample.

Embodiment 2

[0045] Mix 56.0 mg (0.2 mmol) palladium acetate, 2.16 g (8 mmol) potassium persulfate, 6.0 ml (50 mmol) o-xylene and 1.5 ml (20 mmol) trifluoroacetic acid, heat to 45 ° C, stir the reaction for 13 h, and then use saturated The acid in the system was neutralized by sodium bicarbonate, and the organic phase was analyzed by gas chromatography, and the conversion rate of o-xylene to tetramethyl biphenyl was 11.8%, of which 3,3′,4,4′-tetramethylbiphenyl The molar ratio of 2,2',3,3'-tetramethylbiphenyl to 2,3,3',4'-tetramethylbiphenyl is 0.07:0.79:1.

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Abstract

The invention provides a preparation method of tetramethyl biphenyl, which comprises the following steps: mixing o-xylene, oxidizer, additive and metal catalyst, and reacting to obtain the tetramethyl biphenyl, wherein the additive is organic acid and / or organic acid anhydride, and the oxidizer is inorganic oxidizer and / or organic oxidizer containing metal cation. Compared with the prior art of synthesizing tetramethyl biphenyl from halogenated o-xylene, the invention uses the o-xylene for direct coupling to obtain the tetramethyl biphenyl. The raw material o-xylene is cheap and accessible, and the preparation of the halogenated o-xylene is not needed, so the invention lowers the production cost, is simple to operate and has the advantages of mild reaction conditions and low facility request; and under the action of the catalyst, the o-xylene is directly coupled to prepare the tetramethyl biphenyl, and all the carbon atom frameworks of the o-xylene enter the product, so the invention also has the advantage of high economical efficiency of atoms.

Description

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

Claims

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Application Information

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IPC IPC(8): C07C15/14C07C2/84
Inventor 吴强康传清高连勋姚海波丁金英邱雪鹏郭海泉
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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