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-

Method used

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

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0037] Example 1:

[0038] Combine 4-bromo-o-xylene (36.8 g, 0.2 moL), magnesium tape (1.2g, 0.05 moL), anhydrous 2-methyl substituted tetrahydrofuran (52g, 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 to remove magnesium bromide precipitate, the filtrate was distilled to recover 49 g of solvent 2-methyltetrahydrofuran, and 18.5 g of excess brominated o-xylene was recovered, and 145~155 were collected by vacuum distillation o C fraction (pressure 1~4 mmHg). Obtained 19.2 g of 3, 3’, 4, 4’-tetramethylbiphenyl with a yield of 91% (calculated based on magnesium), and a melting point of 74~75 o C.

Example Embodiment

[0039] Example 2:

[0040] Combine 3-chloro-o-xylene (28 g, 0.2 moL), magnesium tape (1.2g, 0.05 moL), anhydrous 2-methyl substituted tetrahydrofuran (43 g, 0.5 moL), isopropyl magnesium chloride (20.4 mg, 0.2 mmoL), anhydrous NiCl 2 (0.064 g, 0.5 mmoL), bipyridine (0.078 g, 0.5 mmoL) mixed in a nitrogen atmosphere, heated to reflux (~115 o C) After 8 hours of reaction, cool and filter to remove magnesium chloride precipitation. The filtrate is distilled to recover 40 g of 2-methyltetrahydrofuran solvent, and 13.5 g of excess 3-chloro-o-xylene is recovered, and 130~145 are collected by vacuum distillation o Fraction C (pressure 1~3 mmHg), 17.9 g of 2, 2’, 3, 3’-tetramethylbiphenyl is obtained, the yield is 85% (calculated based on magnesium), and the melting point is 115~116 o C.

Example Embodiment

[0041] Example 3:

[0042] Combine 4-chloro-o-xylene (14 g, 0.1 moL), magnesium tape (2.4g, 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) Reaction to the complete dissolution of the metal magnesium, that is, the Grignard reagent is completely formed, and then the catalyst anhydrous NiCl is added 2 (0.13 g, 1 mmoL) and triphenylphosphine (0.26 g, 1 mmoL), then add 3-chloro-o-xylene (14 g, 0.1 moL), ~110 o C for coupling reaction for 7 hours, then cooling and filtering to remove inorganic salt precipitation, the filtrate was distilled to recover 46 g of 2,5-dimethyltetrahydrofuran solvent, and 140~145 were collected by vacuum distillation o Fraction C (pressure 1~3 mmHg), obtained 2,3’,3,4’-tetramethylbiphenyl 18.5 g, yield 88% (calculated based on magnesium), melting point 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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