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Para-hydroxybenzoic acid continuous production technique by liquid-phase method

A p-hydroxybenzoic acid, production process technology, applied in the direction of carboxylate preparation, chemical instruments and methods, sulfate/bisulfate preparation, etc., can solve the problem that phenol-containing wastewater is difficult to treat, and achieve easy control of reaction temperature, The effect of shortening the reaction time and increasing the operating flexibility

Inactive Publication Date: 2012-09-26
JIANGSU TIANXIN BIO ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of this invention is to provide a kind of liquid phase method p-hydroxybenzoic acid continuous production process, solve the problem that phenol-containing wastewater is difficult to manage in the existing engineering traditional method p-hydroxybenzoic acid production process

Method used

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Embodiment 1

[0029] Embodiment 1: the production technique of p-hydroxybenzoic acid of the present invention adopts phenol and potassium hydroxide to carry out salification reaction, carries out carboxylation reaction with carbon dioxide after salt formation, finally obtains p-hydroxybenzoic acid product with concentrated sulfuric acid acid analysis; The continuation on the technology has been reduced, and the pollution and waste in the production process have been reduced. The technical process of the present invention comprises: reaction process, filtration process, extraction recovery process, potassium sulfate production process, and concrete technical process is as follows:

[0030] (1) Reaction process

[0031] Mix 50% potassium hydroxide solution, phenol, kerosene and isooctyl alcohol in a certain proportion, the mass ratio is 1:1:2, and the mass ratio of kerosene to isooctyl alcohol is 4:1, put it into the salt-forming reactor, and heat it at 120°C Perform a salt-forming reaction a...

Embodiment 2

[0044] (1) Reaction process

[0045] Mix 50% potassium hydroxide solution, phenol, kerosene and isooctyl alcohol in a certain proportion, the mass ratio is 1:2.5:10, the mass ratio of kerosene to isooctyl alcohol is 2.5:1, put it into the salt-forming reactor, and heat it at 180°C Perform a salt-forming reaction at left and right under normal pressure to obtain potassium phenate;

[0046] Transfer the above materials into the carboxylation reactor, and feed carbon dioxide until the carboxylation is completed, control the temperature at 230°C, and the pressure at 0.6MPa, and the reaction ends after about 4 hours;

[0047] After the carboxylation reaction is finished, add desalted water to the material to obtain an aqueous solution of potassium p-potassium oxybenzoate, unreacted phenol and solvent are recycled back to the salt-forming reaction kettle, and the separation process is realized by phase separation in a phase separation tower.

[0048] Add activated carbon in potassi...

Embodiment 3

[0058] (1) Reaction process

[0059] Mix 50% potassium hydroxide solution, phenol, kerosene and isooctyl alcohol in a certain proportion, the mass ratio is 1:3.5:20, the mass ratio of kerosene to isooctyl alcohol is 1:1, put it into the salt-forming reactor, and heat it at 220°C Perform a salt-forming reaction at left and right under normal pressure to obtain potassium phenate;

[0060] Transfer the above materials into the carboxylation reactor, and feed carbon dioxide until the carboxylation is completed, control the temperature at 260°C, and the pressure at 0.8MPa, and the reaction ends after about 4 hours;

[0061] After the carboxylation reaction is finished, add desalted water to the material to obtain an aqueous solution of potassium p-potassium oxybenzoate, unreacted phenol and solvent are recycled back to the salt-forming reaction kettle, and the separation process is realized by phase separation in a phase separation tower.

[0062] Add gac in the aqueous solution o...

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Abstract

The invention relates to a para-hydroxybenzoic acid continuous production technique by a liquid-phase method, belonging to para-hydroxybenzoic acid production techniques. According to the invention, phenol and potassium hydroxide are subjected to salification reaction, subjected to carboxylation reaction with carbon dioxide, and acidified with concentrated sulfuric acid to obtain the para-hydroxybenzoic acid product. The technique comprises the following steps: reaction: proportioning a potassium hydroxide solution, phenol and a solvent, and adding into a salification reaction kettle to carry out salification reaction, thereby obtaining potassium phenate; filtering: sending the material containing solid para-hydroxybenzoic acid to a centrifugal machine, separating, washing with water to obtain the solid para-hydroxybenzoic acid, and drying to obtain the para-hydroxybenzoic acid; extraction and recycling: sending the filtrate obtained in the filtering step and a washing solution to an extraction column, and extracting with an extractant in the extraction column; and potassium sulfate preparation: drying the wet material with a continuous evaporator to obtain the potassium sulfate product. The invention has the advantages of high unit volume productivity, easy control on production, less environmental pollution, shorter technical process and low production equipment investment, and can easily implement continuous production.

Description

technical field [0001] The invention relates to a production process of p-hydroxybenzoic acid, in particular to a continuous production process of p-hydroxybenzoic acid by liquid phase method. Background technique [0002] The existing p-hydroxybenzoic acid production process uses phenol and potassium hydroxide to carry out a salt-forming reaction, and after forming a salt, carry out a carboxylation reaction with carbon dioxide, then decolorize, and finally acidify with concentrated sulfuric acid, wash with water, centrifugally dehydrate, and dry to obtain a finished product. Since this process is intermittently operated and the process is backward, a large amount of waste gas, waste water, and solid waste are generated during the reaction and intermediate treatment, especially the phenolic waste water produced is difficult to treat, which is not conducive to environmental protection and also affects economic benefits to a certain extent. Contents of the invention [0...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C65/03C07C51/15C01D5/06C01D5/16
Inventor 刘国平童国民钱建华
Owner JIANGSU TIANXIN BIO ENG
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