Preparation method of tetramethylbiphenyl isomers

A technology of tetramethylbiphenyl and isomer, which is applied in the field of preparation of tetramethylbiisomer, can solve the problems of low catalyst efficiency, unfavorable industrial production, large industrial waste residue, etc., and achieves improved conversion rate and reaction yield. efficiency, low price, and reduced operating environment requirements

Active Publication Date: 2014-12-17
HARBIN INST OF TECH AT WEIHAI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main problems of the methods reported in the above-mentioned related patents US5081281, CN1189597, CN101481366, CN102020622B, CN201110202366, etc. are: 1) a large amount of reducing agent and a large amount of catalyst are required, resulting in a large amount of industrial waste; 2) the solvent is a water-soluble high-boiling amide Solvents such as dimethylformamide, dimethylacetamide, N-methylpyridinone, etc., difficult to recover
Not only that, the patent US7425650 also needs an equimolar amount of expensive organic boric acid as another coupling reactant; the patent JP61-22045 uses copper as a catalyst with an equimolar amount of the raw material, and the catalyst efficiency is low; the patent US7893306 uses an equimolar amount of expensive alkyl Grignard reagents as initiators for aromatic halogenated compounds
As we all know, increasing the reaction temperature is conducive to the formation of Grignard reagents from aromatic halogenated compounds with low activity, while tetrahydrofuran or ether has a low boiling point and is volatile. Environmental pollution, ether is easy to cause safety accidents, which is not good for industrial production

Method used

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  • Preparation method of tetramethylbiphenyl isomers
  • Preparation method of tetramethylbiphenyl isomers
  • Preparation method of tetramethylbiphenyl isomers

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Mix 4-bromo-o-xylene (36.8 g, 0.2 moL), magnesium ribbon (1.2 g, 0.05 moL), anhydrous 2-methyl-substituted tetrahydrofuran (52 g, 0.6 moL), iodine (5 mg, 0.02 mmoL), Anhydrous NiCl 2 (0.064 g, 0.5 mmoL), mixed in a nitrogen atmosphere, 90 o C reacted for 8 hours, cooled, filtered off the magnesium bromide precipitate, and the filtrate was distilled to recover 49 g of solvent 2-methyltetrahydrofuran, recovered excess brominated o-xylene 18.5 g, and collected 145 to 155 g of brominated o-xylene by distillation under reduced pressure. o C fraction (pressure 1~4 mmHg). 19.2 g of 3, 3’, 4, 4’-tetramethylbiphenyl was obtained with a yield of 91% (based on magnesium) and a melting point of 74-75 o c.

Embodiment 2

[0040] 3-Chloro-o-xylene (28 g, 0.2 moL), magnesium ribbon (1.2 g, 0.05 moL), anhydrous 2-methyl-substituted tetrahydrofuran (43 g, 0.5 moL), isopropylmagnesium chloride (20.4 mg, 0.2 mmol), anhydrous NiCl 2 (0.064 g, 0.5 mmoL), bipyridine (0.078 g, 0.5 mmoL) were mixed in a nitrogen atmosphere, heated to reflux (~115 o C) After reacting for 8 hours, cool down, filter out the magnesium chloride precipitate, and recover 40 g of 2-methyltetrahydrofuran solvent from the filtrate by distillation, recover 13.5 g of excess 3-chloro-o-xylene, collect 130~145 o Fraction C (pressure 1~3 mmHg), obtained 17.9 g of 2, 2’, 3, 3’-tetramethylbiphenyl, with a yield of 85% (based on magnesium), and a melting point of 115~116 o c.

Embodiment 3

[0042] 4-Chloro-o-xylene (14 g, 0.1 moL), magnesium ribbon (2.4 g, 0.1 moL), anhydrous 2,5-dimethyltetrahydrofuran (50 g, 0.5 moL), iodine (2.5 mg, 0.01 mmoL), reflux under argon atmosphere (~110 o C) React until the metal magnesium is completely dissolved, that is, the Grignard reagent is completely generated, and then add the catalyst anhydrous NiCl 2 (0.13 g, 1 mmol) and triphenylphosphine (0.26 g, 1 mmol), then added 3-chloro-o-xylene (14 g, 0.1 moL), ~110 o C carried out the coupling reaction for 7 hours, then cooled and filtered off the inorganic salt precipitate, and the filtrate was distilled to recover 46 g of 2,5-dimethyltetrahydrofuran solvent, and 140 to 145 g was collected by vacuum distillation. o Fraction C (pressure 1~3 mmHg), 18.5 g of 2,3',3,4'-tetramethylbiphenyl was obtained with a yield of 88% (based on magnesium), and a melting point of 45~46 o c.

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Abstract

The invention discloses a preparation method of tetramethylbiphenyl isomers. By adopting an alkyl-substituted tetrahydrofuran with a boiling point of above 80 DEG C, low toxicity and non water solubility as a solvent system, halogenated o-xylene as a raw material, magnetism as a reducing agent, and a complex formed by salts of transition metals such as nickel, copper, iron, magnesium or cobalt, or additives such as organophosphorus and organic amine as a catalyst, 3,3'4,4'-tetramethylbiphenyl, 2,3'3,4'-tetramethylbiphenyl and 2,2'3,3'-tetramethylbiphenyl isomers are prepared by adopting a coupled reaction. According to the preparation method, the cyclic utilization rate of the solvent reaches above 90 percent, and the yield of compounds of the tetramethylbiphenyl isomers reaches 85-95 percent.

Description

technical field [0001] The invention relates to the field of organic synthetic chemistry, in particular to a preparation method of tetramethyl bi-isomers. Background technique [0002] Biphenyltetraacid dianhydride, referred to as BPDA, is one of the important dianhydride monomers for the synthesis of polyimide materials. For example, 3, 3’, 4, 4’-biphenyltetraacid dianhydride is widely used in heat-resistant polymer materials, and it is one of the most widely used varieties in high-temperature-resistant polyimide materials. In recent years, researchers have found that 2,3',3,4'-biphenyl dianhydride polymers with asymmetric structures have more Higher glass transition temperature and lower melt viscosity, this property is expected to completely change the contradiction between the performance and difficult processing of composite materials for decades. Due to the special properties of polymer composite materials prepared mainly from 2,3',3,4'-biphenyl dianhydride, it has b...

Claims

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Application Information

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IPC IPC(8): C07C15/14C07C1/26
Inventor 高昌录李刚孙秀花
Owner HARBIN INST OF TECH AT WEIHAI
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