CN115650842A - Production process of circulating dehydration high-purity salicylic acid - Google Patents
Production process of circulating dehydration high-purity salicylic acid Download PDFInfo
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- CN115650842A CN115650842A CN202211309355.XA CN202211309355A CN115650842A CN 115650842 A CN115650842 A CN 115650842A CN 202211309355 A CN202211309355 A CN 202211309355A CN 115650842 A CN115650842 A CN 115650842A
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Abstract
The invention discloses a production process of circulating dehydration high-purity salicylic acid, which comprises the following steps: s1: preparing sodium phenolate: reacting phenol with liquid alkali to generate sodium phenolate with higher moisture; s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, dehydrating at normal pressure, then dehydrating at reduced pressure, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration; s3: first and second recovery: recovering phenol with water, and storing the phenol in a reaction kettle for preparing sodium phenolate; s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate for carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water; s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate; the circulating dehydration method used by the invention solves the problem of high dehydration cost, improves the dehydration rate and ensures that the prepared salicylic acid finished product has higher purity.
Description
Technical Field
The invention relates to a production process of circulating dehydration high-purity salicylic acid.
Background
Salicylic acid is a fat-soluble organic acid, is white crystalline powder in appearance, exists in willow bark, white-bead tree leaves and sweet birch in nature, is an important fine chemical raw material, and can be used for preparing aspirin and other medicaments.
The existing salicylic acid is prepared by reacting phenol with sodium hydroxide to generate sodium phenolate, distilling and dehydrating, introducing carbon dioxide to perform a carboxylation reaction to obtain sodium salicylate, and acidifying with sulfuric acid to obtain salicylic acid. The existing dehydration method is distillation dehydration, the cost is high, the dehydration rate is relatively low, a large amount of raw materials are wasted integrally, and the production cost is relatively high. Therefore, there is a need to find a dehydration method for preparing salicylic acid with lower cost and better effect.
Disclosure of Invention
In order to solve the problems, the production process of the cyclic dehydration high-purity salicylic acid provided by the invention has the advantages that the cost is reduced by integrally recycling raw materials, and the content of finished salicylic acid is relatively high by dehydrating the raw materials step by step. The specific technical scheme is as follows:
a production process of circulating dehydration high-purity salicylic acid comprises the following steps:
s1: preparing sodium phenolate: reacting phenol with liquid alkali to generate sodium phenolate with higher moisture;
s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, dehydrating at normal pressure, then dehydrating at reduced pressure, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration;
s3: first and second recovery: recovering phenol with water, and storing the phenol in a reaction kettle for preparing sodium phenolate;
s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate solution to perform carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water;
s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate;
s6: preparing high-purity salicylic acid: centrifugally washing the mixed solution of salicylic acid and sodium sulfate to obtain a wet product of salicylic acid, and drying to obtain a finished product of salicylic acid;
s7: and (3) recovering for the third time: recovering the centrifugate, allowing the centrifugate to flow through the resin layer, adsorbing and recovering phenol through resin, desorbing sodium hydroxide, and storing the sodium phenolate in a reaction kettle for preparing the sodium phenolate;
s8: and (3) cyclic generation: after adding liquid caustic soda to the three recovered solutions, the above operation was repeated.
Preferably, the reaction temperature of the phenol and the liquid caustic soda in the step S1 is 65-100 ℃.
Preferably, the step S2 is performed under normal pressure, and the dehydration conditions are as follows: the steam pressure is 0.4-0.8MPa, and the temperature is 100-130 ℃.
Preferably, the step S2 is performed under reduced pressure, and the dehydration conditions are as follows: the pressure is between-0.05 and-0.1 MPa, the temperature is between 80 and 130 ℃, and the steam pressure is between 0.4 and 0.8MPa.
Preferably, the ratio of the solvent to the materials in the step S2 is 1:1.05 to 1.15.
Preferably, in the step S6, the wet salicylic acid is dried by introducing into a pneumatic drying device.
Preferably, in the step S7, the flow rate of the centrifugate is 0.8-2BV/h.
The invention has the beneficial effects that: the cyclic dehydration high-purity salicylic acid production process adopts a method of recycling while producing to carry out cyclic production during the whole production, recycles raw materials which are not fully reacted through three-step recycling, reduces the production cost, abandons the traditional evaporation dehydration method to carry out dehydration by adopting a step-by-step partial pressure steam dehydration method, has higher efficiency and purer purity, and can be suitable for the production of high-purity salicylic acid in a large range.
Detailed Description
The technical solution of the present invention will be clearly and completely described below with reference to the following embodiments:
example 1:
the embodiment is a production process of circulating dehydration high-purity salicylic acid, which comprises the following steps:
s1: preparing sodium phenolate: phenol reacts with liquid caustic soda to generate sodium phenolate with higher moisture;
s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, dehydrating at normal pressure, then dehydrating at reduced pressure, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration;
s3: first and second recovery: recovering phenol with water, and storing the phenol in a reaction kettle for preparing sodium phenolate;
s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate solution for carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water;
s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate;
s6: preparing high-purity salicylic acid: centrifugally washing the mixed solution of salicylic acid and sodium sulfate to obtain a wet product of salicylic acid, and drying to obtain a finished product of salicylic acid;
s7: and (3) recovering for the third time: recovering the centrifugate, allowing the centrifugate to flow through the resin layer, adsorbing and recovering phenol through resin, desorbing sodium hydroxide, and storing the sodium phenolate in a reaction kettle for preparing the sodium phenolate;
s8: and (3) cyclic generation: after adding liquid caustic soda to the three recovered solutions, the above operation was repeated.
Further, the reaction temperature of the phenol and the liquid caustic soda in the step S1 is 100 ℃.
Further, in the step S2, the dehydration is performed under normal pressure, and the dehydration conditions are as follows: the steam pressure is 0.4MPa, and the temperature is 100 ℃.
Further, in the step S2, dehydration is performed under reduced pressure, and the dehydration conditions are as follows: the pressure is-0.05 MPa, the temperature is 80 ℃, and the steam pressure is 0.4MPa.
Further, the ratio of the feeding solvent to the materials in the step S2 is 1:1.05.
further, in the step S6, the wet salicylic acid is dried by introducing into an airflow drying device.
Further, in the step S7, the flow rate of the centrifugate is 0.8BV/h.
Example 2
The embodiment is a production process of circulating dehydration high-purity salicylic acid, which comprises the following steps:
s1: preparing sodium phenolate: reacting phenol with liquid alkali to generate sodium phenolate with higher moisture;
s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, performing dehydration under normal pressure, performing reduced pressure dehydration, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration;
s3: first and second recovery: recovering phenol with water, and storing the phenol in a reaction kettle for preparing sodium phenolate;
s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate solution for carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water;
s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate;
s6: preparing high-purity salicylic acid: centrifugally washing the mixed solution of salicylic acid and sodium sulfate to obtain a wet product of salicylic acid, and drying to obtain a finished product of salicylic acid;
s7: and (3) third recovery: recovering the centrifugate, allowing the centrifugate to flow through the resin layer, adsorbing and recovering phenol through resin, desorbing sodium hydroxide, and storing the sodium phenolate in a reaction kettle for preparing the sodium phenolate;
s8: and (3) cyclic generation: after adding liquid caustic soda to the solution recovered three times, the above operation was repeated.
Further, the reaction temperature of the phenol and the liquid caustic soda in the step S1 is 100 ℃.
Further, in the step S2, the dehydration is performed under normal pressure, and the dehydration conditions are as follows: the steam pressure is 0.8MPa, and the temperature is 130 ℃.
Further, in the step S2, dehydration is performed under reduced pressure, and the dehydration conditions are as follows: the pressure is-0.105 MPa, the temperature is 130 ℃, and the steam pressure is 0.8MPa.
Further, the ratio of the feeding solvent to the materials in the step S2 is 1:1.15.
further, in the step S6, the wet salicylic acid is dried by introducing into an airflow drying device.
Further, in the step S7, the flow rate of the centrifugate is 2BV/h.
Example 3
The embodiment is a production process of circulating dehydration high-purity salicylic acid, which comprises the following steps:
s1: preparing sodium phenolate: reacting phenol with liquid alkali to generate sodium phenolate with higher moisture;
s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, dehydrating at normal pressure, then dehydrating at reduced pressure, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration;
s3: first and second recovery: recovering the phenol with water and storing the phenol in a reaction kettle for preparing sodium phenolate;
s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate solution to perform carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water;
s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate;
s6: preparing high-purity salicylic acid: centrifugally washing the mixed solution of salicylic acid and sodium sulfate to obtain a wet product of salicylic acid, and drying to obtain a finished product of salicylic acid;
s7: and (3) recovering for the third time: recovering the centrifugate, allowing the centrifugate to flow through the resin layer, adsorbing and recovering phenol through resin, desorbing sodium hydroxide, and storing the sodium phenolate in a reaction kettle for preparing the sodium phenolate;
s8: and (3) cyclic generation: after adding liquid caustic soda to the three recovered solutions, the above operation was repeated.
Further, the reaction temperature of phenol and liquid caustic soda in the step S1 is 85 ℃.
Further, in the step S2, the dehydration is performed under normal pressure, and the dehydration conditions are as follows: the steam pressure is 0.6MPa, and the temperature is 115 ℃.
Further, in the step S2, the dehydration is performed under reduced pressure, and the dehydration conditions are as follows: the pressure is-0.07 MPa, the temperature is 100 ℃, and the steam pressure is 0.6MPa.
Further, the ratio of the feeding solvent to the materials in the step S2 is 1:1.1.
further, in the step S6, the wet salicylic acid is dried by introducing into an airflow drying device.
Further, in the step S7, the flow rate of the centrifugate is 1.4BV/h.
Effect example 1
At 5 m 3 The reactor volume is for example:
dehydrating under normal pressure: the steam pressure is 0.4-0.8MPa, and the temperature is controlled to be less than 120 ℃ so as to avoid the reaction kettle from being washed by water.
And (3) decompression dehydration: the vacuum degree is controlled to be-0.09 MPa, the temperature in the reaction kettle is controlled to be 120-85 ℃, and the steam pressure of the jacket is controlled to be 0.6-0.8MPa.
Optimal conditions of solvent with water are as follows: phenol is used as a solvent with water, and the total purifying proportion of the solvent to phenol of salified prepared materials is 1:1.05.
the sodium salicylate is acidified by dilute sulphuric acid, and the wet salicylic acid is obtained after centrifugal washing, wherein the water content is 10 percent, and the salicylic acid content is over 99.5 percent after drying.
Comparative example 1
At 5 m 3 The reactor volume is for example:
the preparation method is as in example 1, the step S2 of dehydration is changed into the step of evaporation dehydration of the materials, other steps are not changed, dilute sulfuric acid is used for acidifying sodium salicylate, and the wet salicylic acid is obtained after centrifugal washing, wherein the water content is 21%.
In conclusion, the cyclic dehydration high-purity salicylic acid production process adopts a method of recycling while producing during production, recycles the raw materials which are not fully reacted through two-step recycling, reduces the production cost, abandons the traditional evaporation dehydration method and adopts a method of fractional-step steam dehydration instead, has higher efficiency and purer purity, and can be widely applied to the production of high-purity salicylic acid.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A production process of circulating dehydration high-purity salicylic acid is characterized in that: the method comprises the following steps:
s1: preparing sodium phenolate: reacting phenol with liquid alkali to generate sodium phenolate with higher moisture;
s2: step-by-step dehydration: introducing the sodium phenolate solution into a steam dehydration furnace, performing dehydration under normal pressure, performing reduced pressure dehydration, introducing into the reduced pressure steam dehydration furnace for secondary dehydration during dehydration, and finally introducing into a solvent for secondary dehydration;
s3: first and second recovery: recovering phenol with water, and storing the phenol in a reaction kettle for preparing sodium phenolate;
s4: and (3) carboxylation reaction: introducing carbon dioxide into the dehydrated sodium phenolate solution for carboxylation to generate sodium salicylate, and vaporizing the sodium salicylate through high-temperature steam after reaction to remove the solvent and water;
s5: acid precipitation: reacting sodium salicylate with dilute sulfuric acid to generate salicylic acid suspension and sodium sulfate;
s6: preparing high-purity salicylic acid: centrifugally washing the mixed solution of salicylic acid and sodium sulfate to obtain a wet product of salicylic acid, and drying to obtain a finished product of salicylic acid;
s7: and (3) recovering for the third time: recovering the centrifugate, allowing the centrifugate to flow through the resin layer, adsorbing and recovering phenol through resin, desorbing sodium hydroxide, and storing the sodium phenolate in a reaction kettle for preparing the sodium phenolate;
s8: and (3) cyclic generation: after adding liquid caustic soda to the three recovered solutions, the above operation was repeated.
2. The cyclic dehydration high-purity salicylic acid production process according to claim 1, characterized in that: the reaction temperature of the phenol and the liquid caustic soda in the step S1 is 65-100 ℃.
3. The cyclic dehydration high-purity salicylic acid production process according to claim 1, characterized in that: and in the step S2, normal-pressure dehydration is carried out, and the dehydration conditions are as follows: the steam pressure is 0.4-0.8MPa, and the temperature is 100-130 ℃.
4. The cyclic dehydration high-purity salicylic acid production process according to claim 1, characterized in that: and in the step S2, the pressure is reduced for dehydration, and the dehydration conditions are as follows: the pressure is between-0.05 and-0.1 MPa, the temperature is between 80 and 130 ℃, and the steam pressure is between 0.4 and 0.8MPa.
5. The process for producing the circulating type dehydrated high-purity salicylic acid according to claim 1, wherein the process comprises the following steps: the ratio of the feeding solvent to the materials in the step S2 is 1:1.05 to 1.15.
6. The cyclic dehydration high-purity salicylic acid production process according to claim 1, characterized in that: and in the step S6, the wet salicylic acid is dried by introducing airflow drying equipment.
7. The process for producing the circulating type dehydrated high-purity salicylic acid according to claim 1, wherein the process comprises the following steps: in the step S7, the flow rate of the centrifugate is 0.8-2BV/h.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03178947A (en) * | 1989-09-20 | 1991-08-02 | Yoshitomi Pharmaceut Ind Ltd | Production of phenolic compound |
| JPH1087560A (en) * | 1996-09-10 | 1998-04-07 | Toray Ind Inc | Complex, production thereof, and production of p-hydroxybenzoic acid |
| JPH11171819A (en) * | 1997-10-03 | 1999-06-29 | Ueno Fine Chem Ind Ltd | Production of aromatic hydroxycarboxylic acid |
| JP2002371020A (en) * | 2001-06-19 | 2002-12-26 | Mitsui Chemicals Inc | Method for producing phenol |
| CN104998429A (en) * | 2015-08-17 | 2015-10-28 | 山东新华制药股份有限公司 | Dehydration technology and device for salicylic acid intermediate sodium phenoxide |
| CN107141215A (en) * | 2017-05-11 | 2017-09-08 | 镇江高鹏药业有限公司 | A kind of salicylic acid preparation method of environmental protection in high yield |
| CN113336638A (en) * | 2021-06-22 | 2021-09-03 | 宁夏万香源生物科技有限公司 | Efficient synthesis method of salicylic acid |
| CN214611645U (en) * | 2021-02-02 | 2021-11-05 | 新乡赛普瑞特环保科技有限公司 | Recovery system of phenol and salicylic acid |
-
2022
- 2022-10-25 CN CN202211309355.XA patent/CN115650842A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03178947A (en) * | 1989-09-20 | 1991-08-02 | Yoshitomi Pharmaceut Ind Ltd | Production of phenolic compound |
| JPH1087560A (en) * | 1996-09-10 | 1998-04-07 | Toray Ind Inc | Complex, production thereof, and production of p-hydroxybenzoic acid |
| JPH11171819A (en) * | 1997-10-03 | 1999-06-29 | Ueno Fine Chem Ind Ltd | Production of aromatic hydroxycarboxylic acid |
| JP2002371020A (en) * | 2001-06-19 | 2002-12-26 | Mitsui Chemicals Inc | Method for producing phenol |
| CN104998429A (en) * | 2015-08-17 | 2015-10-28 | 山东新华制药股份有限公司 | Dehydration technology and device for salicylic acid intermediate sodium phenoxide |
| CN107141215A (en) * | 2017-05-11 | 2017-09-08 | 镇江高鹏药业有限公司 | A kind of salicylic acid preparation method of environmental protection in high yield |
| CN214611645U (en) * | 2021-02-02 | 2021-11-05 | 新乡赛普瑞特环保科技有限公司 | Recovery system of phenol and salicylic acid |
| CN113336638A (en) * | 2021-06-22 | 2021-09-03 | 宁夏万香源生物科技有限公司 | Efficient synthesis method of salicylic acid |
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