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Preparation method of 3,5-difluoro-4-trifluoro-methoxyl bromobenzene

A technology of trifluoromethoxy bromobenzene and difluorophenol is applied in the field of preparation of TFT liquid crystal intermediates, and can solve the problems of poor atom economy, potential safety hazards, long reaction steps and the like

Active Publication Date: 2010-08-04
ZHEJIANG YONGTAI TECH CO LTD
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003]3,5-difluoro-4 trifluoromethoxy bromobenzene is an important intermediate of TFT-LCD liquid crystal material, the patent DE4221152C1 of German Merck Company reported Using 2,6-difluorotrifluoromethoxybenzene as raw material, synthesize 3,5-difluoro-4-trifluoromethoxybromobenzene after nitration, bromination, diazotization, and deamination. This method reacts The steps are long, and the deamination yield in the last step is only 39%, the atom economy is poor, and the instability of the diazo solution brings safety hazards to the production

Method used

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  • Preparation method of 3,5-difluoro-4-trifluoro-methoxyl bromobenzene

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Embodiment 1

[0021] Embodiment 1: Preparation of 2,6-difluoro-4-bromophenol

[0022] Put 300g (2.31mol) of 2,6 difluorophenol and 1000g of carbon tetrachloride into a 2000ml four-neck flask, cool to 22°C, and start to drop 555g (3.47mol) of bromine and 800g of carbon tetrachloride solution. The dropwise addition is exothermic, and the temperature of the system is controlled at 20-22°C, and the temperature is kept for 1 hour after the addition is completed. Stop the reaction, add 500ml of water to the system, add 52g of sodium sulfite to eliminate excess bromine, let stand to separate layers, extract the water layer with 150g of carbon tetrachloride, combine the oil layers, and distill the oil layers to obtain 2,6-difluoro-4-bromophenol 432g, content 99.5%, yield 89.6%. Such as figure 1 As shown, NMR data analysis: 1 H-NMR (CDCl 3 , 500Hz) δ: 5.41 (m, 1H), 7.08 (m, 2H).

Embodiment 2

[0023] Embodiment 2: Preparation of 2,6-difluoro-4-bromophenol

[0024] According to Example 1, 1950 g of 1,2-dichloroethane was used instead of carbon tetrachloride to obtain 407 g of 2,6-difluoro-4-bromophenol with a content of 99.0% and a yield of 84.3%.

Embodiment 3

[0025] Embodiment 3: Preparation of 2,6-difluoro-4-bromophenol

[0026] According to Example 1, the amount of bromine was increased to 736g (4.6mol), and the reaction gave 434g of 2,6-difluoro-4-bromophenol with a content of 89.0% and a yield of 90.0%.

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Abstract

The invention relates to the field of a liquid-crystal intermediate of an electronic material, in particular to a preparation method of a fluorine-containing liquid-crystal intermediate 3, 5-difluoro-4-trifluoro-methoxyl bromobenzene. The 3,5-difluoro-4-trifluoro-methoxyl bromobenzene is prepared from 2,6-difluoro phenol by bromine substitution and coupling. The preparation method of the 3,5-difluoro-4-trifluoro-methoxyl bromobenzene has the advantages of mild reaction condition, strong operability, high atom economy, simple process and high-purity and stable-quality obtained product and is beneficial to the realization of industrialization, has and completely accords with the use requirement as the liquid-crystal intermediate.

Description

technical field [0001] The present invention relates to the technical field of preparation methods of TFT liquid crystal intermediates, and more to the field of preparation methods of 3,5-difluoro-4-trifluoromethoxybromobenzene. Background technique [0002] LCD display is currently a new type of display device with the widest application field, the fastest development and the largest industrial scale. According to the data released by the market research organization DisplaySearch, the sales volume of the global FPD market in 2007 was 107 billion US dollars. Among them, 67% of the sales are accounted for by the top three LCD TVs, LCD monitors and notebook computers. At the same time, according to the agency's survey, before 2016, the average annual growth rate of LCDs will remain at about 1%, and LCDs for mobile terminals will continue to grow at an average annual rate of 6%. In addition, compared with the average annual growth rate of 3% for notebook computer LCDs, deskt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/225C07C41/16
Inventor 钟建新邵鸿鸣舒祝金周日喜林娇华
Owner ZHEJIANG YONGTAI TECH CO LTD
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