Method for preparing 4-hydroxy-4'-cyanobiphenyl

A technology of cyanobiphenyl and hydroxyl, which is applied in the field of preparing 4-hydroxy-4'-cyanobiphenyl, can solve the problems of harsh reaction conditions, large discharge of three wastes, and low overall yield, and achieve simplification of the reaction process, The effect of large discharge of three wastes and small market capacity

Active Publication Date: 2019-06-21
宁夏中星显示材料有限公司
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  • Abstract
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  • Application Information

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Problems solved by technology

In this method, the total yield is not high, and the organolithium reagent is expensive, the reaction conditions are harsh, and the price of p-bromoxynil is relatively high, so it is not suitable for industrial production
[0014] The above methods all have obvious disadvantages, such as the classic method generally has long steps, low yield, large discharge of three wastes, and the comprehensive yield is lower than 60%.
Although the coupling method is simple in process, the raw materials used are not easy to obtain. Considering the synthesis of raw materials such as p-hydroxyphenylboronic acid and p-cyanophenylboronic acid, the total yield from the initial raw material p-bromophenol is also about 60%.

Method used

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  • Method for preparing 4-hydroxy-4'-cyanobiphenyl

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036]Assemble a 500ml three-necked flask reaction device, put 34.6g (0.2mol) of p-bromophenol (0.2mol) and 19.75g (0.25mol) of pyridine into the three-necked flask, add 100ml of 2-methyltetrahydrofuran, control the temperature in an ice-water bath to less than 10°C, and protect with nitrogen Add 25.92g (0.24mol) of trimethylchlorosilane in 50ml of 2-methyltetrahydrofuran solution dropwise, and control the temperature not to exceed 20°C. ×2 wash the reaction liquid, and dry it with 10 g of anhydrous magnesium sulfate for later use.

[0037] Take another 1000ml three-necked flask, add 5.76g (0.24mol) of magnesium chips, put in a water bath at 30°C, add dropwise the p-trimethylsilyloxybromobenzene 2-methyltetrahydrofuran solution prepared in the previous step, and initiate the preparation of the Grignard reagent. After completion, continue to react at 30-35°C for 2 hours, cool down to -15°C in an ice-salt bath, add 100ml of 2-methyltetrahydrofuran solution of 41.6g (0.4mol) of t...

Embodiment 2

[0038] Embodiment 2 (industrialized scale)

[0039] Clean the 500L reactor device and dry it. Put 34.6kg of p-bromophenol and 20.19kg of dihydropyran into the reactor, add 100L of xylene, control the temperature of the freezing liquid below -10°C, and add three 25.92kg of methyl chlorosilane in 50L xylene solution, the temperature control does not exceed 0°C, after dropping, the temperature of the cooling liquid temperature control system is -5~5°C, the reaction is terminated after 4 hours of reaction, and the reaction solution is washed with 50L×2 saturated saline, 10kg of anhydrous magnesium sulfate was dried for later use.

[0040] In another dry 1000L reaction kettle, add 5.76kg of magnesium chips, heat to 30°C, add dropwise the p-trimethylsiloxy bromoxylene solution prepared in the previous step, trigger the preparation of Grignard reagent, and continue to control React at 30-35°C for 4 hours, cool the freezing liquid to -10°C, add 100L xylene solution of 41.6kg of trime...

Embodiment 3

[0041] Embodiment 3 (industrialized scale)

[0042] Clean and dry the 500L reactor device, put 34.6kg of p-bromophenol and 17kg of imidazole in the reactor, add 100L of dioxane, control the temperature of the freezing liquid below 20°C, and add triisopropyl group dropwise under nitrogen protection Chlorosilane 46.08kg in 50L dioxane solution, the temperature control does not exceed 30°C, after dropping, the water bath temperature is controlled at 15-25°C, the reaction is terminated after 4 hours of reaction, the reaction solution is washed with saturated saline 50L×2, and 10kg of anhydrous Magnesium sulfate is dried for later use.

[0043] In another dry 1000L reaction kettle, add 6kg of magnesium chips, heat to 40°C, add dropwise the prepared p-triisopropylsilyloxybromobenzenedioxane solution to initiate the preparation of Grignard reagent. Continue to control the temperature at 50-60°C for 4 hours, cool down the cooling liquid to 20°C, add 45.12 kg of triisopropyl borate in...

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Abstract

The invention relates to a method for preparing 4-hydroxy-4'-cyanobiphenyl, and belongs to the technical field of organic synthetic chemistry. According to the method, substituted boronic acid is first prepared by taking p-bromophenol as a raw material, and then the substituted boronic acid is prepared into the 4-hydroxy-4'-cyanobiphenyl, wherein PG in the substituted boronic acid is a protectinggroup, the substituted boronic acid and p-chlorobenzonitrile are subjected to a Suzuki coupling reaction in the presence of a solvent, an alkali and a catalyst, deprotection is performed to obtain the4-hydroxy-4'-cyanobiphenyl, the molar ratio of p-bromophenol, p-chlorobenzonitrile and the alkali is 1.0:(1.0-1.5):(2.0-4.0), and the temperature of the Suzuki coupling reaction is 50-120 DEG C. Themethod provided by the invention has the advantages that the production efficiency is high, three wastes are fewer, raw materials are easy to obtain, the cost is low, and the obtained product, namely,4-hydroxy-4'-cyanobiphenyl, is high in yield.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis chemistry and relates to the preparation of liquid crystal intermediates, in particular to a method for preparing 4-hydroxy-4'-cyanobiphenyl. Background technique [0002] PDLC is the abbreviation of Polymer Dispersed Liquid Crystal in English, and its Chinese name is Polymer Dispersed Liquid Crystal. Polymer-dispersed liquid crystal (PDLC) is a mixture of low molecular liquid crystal (liquid crystal, abbreviated as LC) and prepolymer KuerUV65 glue, and undergoes polymerization reaction under certain conditions to form micron-sized liquid crystal droplets uniformly dispersed in polymer In the network, the dielectric anisotropy of liquid crystal molecules is used to obtain materials with electro-optic response characteristics. It mainly works between the scattering state and the transparent state and has a certain gray scale. Polymer dispersed liquid crystal film is a film material with ...

Claims

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Application Information

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IPC IPC(8): C07C253/30C07C255/53
CPCY02P20/55
Inventor 岳刚王志强丁秋月禹凯王利民关登仕
Owner 宁夏中星显示材料有限公司
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