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Preparation method of p-substituted benzyl alcohol

A technology of benzyl alcohol and hydrolysis reaction, applied in the field of preparation of para-substituted benzyl alcohol, can solve problems such as being unsuitable for industrial production, using a large amount of solvent water, increasing production costs, etc., achieving mild conditions, reducing the amount of water used, reducing effect of dosage

Pending Publication Date: 2020-07-31
新乡市锦源化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The hydrolysis to substituted benzyl halide generally takes water as reaction solvent, and in the presence of inorganic base, high-temperature hydrolysis obtains target product, but this method easily produces impurity two pairs of substituted benzyl ethers, causes low product yield, poor purity (CN 105801349, CN 105348107)
Patent CN108892618 reports that with self-made p-nitrobenzyl chloride as raw material, now reacts with sodium acetate in toluene solvent to generate p-nitrobenzyl acetate, and then in methanol, adds alkali hydrolysis to obtain p-nitrobenzyl alcohol. This method is larger The production of impurities is reduced to a certain extent, but two kinds of organic solvents are used in the reaction process, which greatly increases the safety risk of the process, increases environmental pollution, increases production costs, and is not suitable for industrial production
[0004] At present, the hydrolysis of substituted benzyl halides is a method most suitable for the industrialization of substituted benzyl alcohols, but due to the many side reactions and low yield in the method reported in the prior art, and the use of solvent water is large and the waste water is large, therefore It is necessary to develop a green synthesis process with high yield, low cost, less waste and less investment

Method used

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  • Preparation method of p-substituted benzyl alcohol
  • Preparation method of p-substituted benzyl alcohol
  • Preparation method of p-substituted benzyl alcohol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Add 100 g of p-nitrobenzyl bromide (85.3% HPLC purity, 0.395 mol of purity), 400 g of water, 10.7 g of sodium formate (0.157 mol) into a 1000 ml flask, and heat up to 100-105° C. Slowly add 110 g (0.208 mol) of 20% sodium carbonate solution dropwise, control the pH of the reaction solution to be 7-7.5, and keep the reaction for 1 h after dropping. Add 300g of toluene, stir evenly, let it stand for stratification, evaporate 85-90g of water from the lower layer of water layer, and then directly use it as a hydrolysis agent and solvent in the next batch of hydrolysis reactions; the upper layer of oil layer drops to about 20°C to crystallize, filter, and dry 57.2 g (0.374 mol) of p-nitrobenzyl alcohol was obtained, with a yield of 94.7% (based on the content of p-nitrobenzyl bromide) and a HPLC purity of 99.5%.

[0028] Under the same reaction conditions, see the following table for the impact results of the water layer application on the yield and quality of the finished p...

Embodiment 2

[0031] Add 100 g of p-nitrobenzyl bromide (85.3% HPLC purity, 0.395 mol of purity), 400 g of water, 10.7 g of sodium formate (0.157 mol) into a 1000 ml flask, and heat up to 100-105° C. Slowly add 166 g (0.415 mol) of 10% sodium hydroxide solution dropwise, control the pH of the reaction solution to be 7-7.5, and keep the reaction for 1 h after dropping. Add 300g of toluene, stir evenly, let it stand for stratification, evaporate 145-150g of water from the lower layer of water layer, and then directly use it as a hydrolysis agent and solvent in the next batch of hydrolysis reactions; the upper layer of oil layer drops to about 20°C to crystallize, filter, and dry 56.5 g (0.369 mol) of p-nitrobenzyl alcohol was obtained, with a yield of 93.4% (based on the pure content of p-nitrobenzyl bromide), and an HPLC purity of 99.2%.

[0032] Under the same reaction conditions, see the following table for the impact results of the water layer application on the yield and quality of the f...

Embodiment 3

[0035] Add 100g of p-nitrobenzyl chloride (HPLC purity 89.1%, pure 0.52mol), water 500g, sodium formate 14.1g (0.207mol) in a 1000ml flask, heat up to 100-105°C, slowly add 20% sodium carbonate solution 144.7 g (0.273mol), control the pH of the reaction solution to be 7-7.5, keep the reaction for 1 hour after dropping, add 380g of toluene, stir evenly, let it stand for stratification, evaporate 115-120g of water from the lower layer of water layer, and directly use it as a hydrolysis agent and solvent jacket into the next batch of hydrolysis reaction; the upper oil layer is down to about 20 DEG C to crystallize, filter, and dry to obtain 73.2g (0.478mol) of p-nitrobenzyl alcohol product, with a yield of 92.0% (calculated in terms of pure p-nitrobenzyl chloride content) ), HPLC purity 99.4%.

[0036] Under the same reaction conditions, see the following table for the impact results of the water layer application on the yield and quality of the finished product.

[0037]

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Abstract

The invention relates to the technical field of fine chemical synthesis. The invention also discloses a preparation method of p-substituted benzyl alcohol. The preparation method comprises the following steps: taking a p-substituted benzyl halide as a raw material; adding a hydrolysis agent into a water solvent; simultaneous dropwise adding an aqueous alkali, carrying out hydrolysis reaction whilean ester is generated, so that the generation of impurities is effectively controlled, and the use amount of the hydrolysis agent is reduced; and specifically, first, adding the hydrolysis agent intowater, stirring for dissolving, adding a compound shown as a formula I, dropwise adding the aqueous alkali, carrying out heat preservation reaction, cooling a reaction solution to a refining temperature after hydrolysis is completed, adding a certain amount of a refining solvent, stirring for dissolving organic matters, standing for layering, evaporating excessive part of water from a lower waterlayer while the lower water layer is hot, and applying an obtained product to the next hydrolysis reaction; cooling and crystallizing an organic layer, filtering and drying to obtain a p-substitutedbenzyl alcohol finished product. The hydrolysis agent is introduced, so that the generation of impurities is reduced, the product yield and quality are improved, no organic solvent is added in the reaction process, the safety risk is reduced, the environmental pollution is reduced, the operation is simple, and the conditions are mild.

Description

technical field [0001] The invention relates to the technical field of synthesis of fine chemicals, in particular to a method for preparing p-substituted benzyl alcohol. Background technique [0002] P-substituted benzyl alcohol is an important class of fine chemicals and has important applications in the field of synthetic pharmaceuticals. For example, p-nitrobenzyl alcohol is a key intermediate of penem antibiotics, and 4-biphenyl alcohol is also an important raw material for the synthesis of drug intermediates. [0003] At present, there are mainly three methods for preparing p-substituted benzyl alcohol: p-substituted formaldehyde reduction method, p-substituted formic esterification and re-reduction method, and p-substituted benzyl halide hydrolysis method, and the p-substituted benzyl halide hydrolysis method is currently the most industrialized method. The hydrolysis to substituted benzyl halide generally takes water as reaction solvent, and in the presence of inorga...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/43C07C205/19C07C67/11C07C69/07C07C29/09C07C33/24
CPCC07C201/12C07C67/11C07C29/095C07C205/43C07C205/19C07C69/07C07C33/24
Inventor 汪祝胜钟智奎朱亚洲张斌唐鹤
Owner 新乡市锦源化工有限公司