Efficient synthesis method of salicylic acid

A synthesis method and technology of salicylic acid, which are applied in the field of high-efficiency synthesis of salicylic acid, can solve the problems of long reaction time, complicated dehydration process, and low production efficiency, and achieve shortened carboxylation reaction time, high dehydration efficiency, and high production efficiency. inefficient effect

Pending Publication Date: 2021-09-03
宁夏万香源生物科技有限公司
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  • Abstract
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Problems solved by technology

[0004] In view of this, it is necessary to provide a kind of efficient synthetic method of salicylic acid to solve the dehydration process in the reaction process is complicated, the energy consumption is large, the reaction process time is long, the production efficiency is low, and the problem of low yield

Method used

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preparation example Construction

[0021] The embodiment of the present invention provides a high-efficiency synthesis method of salicylic acid, comprising the following steps:

[0022] (S 1 ) high-efficiency dehydration of sodium phenate solution: put sodium phenate solution into a medium pressure kettle, remove part of the water under reduced pressure, and then add phenol, wherein part of phenol and water form a binary azeotrope, and the binary azeotrope is separated under negative pressure to obtain drying a leavening compound consisting of phenol and sodium phenate;

[0023] (S 2 ) Carboxylation reaction: CO is introduced into the dry bulky compound above 2 , Sodium phenate and CO in the bulky compound 2 The reaction generates sodium salicylate, and after the reaction is over, the phenol that does not participate in the reaction is separated under negative pressure conditions to obtain sodium salicylate;

[0024] (S 3 ) Acidification reaction: adding inorganic acid to sodium salicylate to obtain salicy...

Embodiment 1

[0036] Pilot Experiment of Synthesis of Salicylic Acid

[0037] (S 0 ) Preparation of sodium phenoxide solution: take 90kg of sodium hydroxide, prepare a 40% solution with distilled water, weigh 200kg of phenol, prepare a 54% solution with distilled water, add the phenol solution into the sodium hydroxide solution to react, control The reaction temperature is 85° C., and the reaction time is 10 to 15 minutes to obtain a sodium phenoxide solution.

[0038] (S 1 ) High-efficiency dehydration of sodium phenate solution: put 590kg of the above-mentioned sodium phenate solution into a medium pressure kettle, vacuumize, start decompression distilling, and when the solution becomes thick, check the water content, and stop decompression distilling when the water content is about 45% , the distilled water is reused (S 0 ) step to prepare sodium hydroxide lye, add 200kg of phenol to the obtained sodium phenate fluid, vacuumize, heat up to 90°C, evaporate and collect the binary azeotr...

Embodiment 2

[0046] Scaled-up process for the synthesis of salicylic acid

[0047] (S 0 ) Preparation of sodium phenate solution: Weigh 270kg of sodium hydroxide, prepare a 40% solution with distilled water or decompressed water in the carboxylation station, weigh 600kg of phenol (which can be the water-carrying phenol separated in the carboxylation station), and prepare into a 54% solution, the phenol solution was added into the sodium hydroxide solution to react, the reaction temperature was controlled to be 75° C., and the reaction time was 30 to 45 minutes to obtain a sodium phenoxide solution.

[0048] (S 1 ) High-efficiency dehydration of sodium phenate solution: put 1500kg of the above-mentioned sodium phenate solution into a medium pressure kettle, vacuumize, start decompression distilling, and when the solution becomes thick, check the water content, and stop decompression distilling when the water content is about 45% , add 600kg of phenol to the obtained sodium phenate fluid, ...

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Abstract

An efficient synthesis method of salicylic acid belongs to the technical field of salicylic acid synthesis. The dehydration method adopted by the invention comprises the following steps: vacuumizing a sodium phenate solution for primary dehydration, adding phenol into the sodium phenate solution when the water content of the sodium phenate solution reaches about 45% such that a part of the phenol and water form a binary azeotrope, and separating the binary azeotrope under negative pressure condiction to achieve the purpose of taking out water by the phenol. The residual phenol and the sodium phenate form the bulky compound under the vacuum condition, and the bulky compound has the large specific surface area, such that the reaction rate is accelerated, the reaction time is substantially shortened, and the production efficiency is improved when the CO2 is introduced to perform the carboxylation reaction; meanwhile, the binary azeotrope and phenol separated in the process can be recycled, so that resources are saved, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of salicylic acid synthesis, in particular to a high-efficiency synthesis method of salicylic acid. Background technique [0002] Salicylic acid is a lipophilic monohydroxybenzoic acid with a wide range of uses, and is an important raw material for fine chemicals such as medicine, spices, dyes and rubber additives. As science advances, more uses for salicylic acid are developed. For example, it can be used to combine with a variety of metals to make a soil conditioner; it can be used to prevent and treat certain plant diseases by using its antibacterial properties. In addition, o-hydroxybenzoic acid is also used as a compound component for flame retardants and fabric protection. agent. [0003] At present, salicylic acid for industrial use is mainly synthesized. The synthetic method of salicylic acid is mainly to use phenol as the starting material, react with sodium hydroxide to generate sodium phenate, o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/15C07C51/02C07C65/10
CPCC07C51/15C07C51/02C07C65/10
Inventor 宋公龙沈华杨育清李向前
Owner 宁夏万香源生物科技有限公司
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