CN1289760A - Process for preparing salicylic acid by solvent method - Google Patents
Process for preparing salicylic acid by solvent method Download PDFInfo
- Publication number
- CN1289760A CN1289760A CN 00123036 CN00123036A CN1289760A CN 1289760 A CN1289760 A CN 1289760A CN 00123036 CN00123036 CN 00123036 CN 00123036 A CN00123036 A CN 00123036A CN 1289760 A CN1289760 A CN 1289760A
- Authority
- CN
- China
- Prior art keywords
- phenol
- salicylic acid
- reaction
- sodium
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A process for preparing salicylic acid by solvent method includes such steps as neutralizing phenol with sodium hydroxide to obtain sodium phenate, vacuum dewatering it in organic solvent C8H17OH at 40-140 deg.C and 0-0.1 MPa of vacuum level, measuring water content, introducing excess CO2, carboxylating reaction at 110-190 deg.C and 0-0.8 MPa, cooling in nitrogen atmosphere, adding water, reclaiming the separated-out organic solvent containing phenol and acidifying water phase to obtain 99.56% salicylic acid. Its advantages are short reaction time, high selectivity and total recovery rate, and no environmental pollution.
Description
The present invention belongs to the field of salicylic acid producing technology with phenol, sodium hydroxide, carbon dioxide, sulfuric acid, etc. as material. In particular to a method for preparing salicylic acid by dehydrating in the presence of an organic solvent, dissolving the dehydrated sodium phenolate and the organic solventinto a uniform and transparent liquid and carrying out carboxylation reaction on the liquid and carbon dioxide.
The salicylic acid is mainly used in the industries of medicine, pesticide, dye and the like, and the traditional Koble-Skhmitt solid phase carboxylation method is still adopted to produce the salicylic acid at home and abroad before the invention is made. The method has the disadvantages that the phenol sodium salt is dehydrated into dry powder which is easy to burn and explode. The reaction is a gas-solid reaction, the contact of the reaction is poor, the local overheating is easy, the p-hydroxybenzoic acid is easy to generate, the product is difficult to refine, and the sublimation-grade salicylic acid can be obtained only by using special vacuum sublimation equipment.
In recent years, the solvent process for the preparation of salicylic acid has been reported (C, A, Vol121990), which uses the C-alkylbenzene as the starting material6H6nRn(R = low-carbon alkane, n =1-4) is a solvent, the alkali metal salt of phenol reacts with carbon dioxide to prepare salicylic acid, the sodium salt of phenol is insoluble in alkylbenzene, the reaction is a gas-liquid-solid three-phase reaction, the reaction effect is poor, the process flow is long, and industrial production is difficult.
The invention aims to provide a novel process for preparing salicylic acid by a solvent method, which adopts an organic solvent with good intermiscibility with sodium phenolate to ensure that reaction liquid is uniform and transparent liquid, and removes water in the sodium phenolate to directionally produce the salicylic acid.
The object of the invention is achieved by the following technical measures.
The technological process for preparing salicylic acid is shown in the attached drawing. Neutralizing phenol with sodium hydroxide water solution to obtain phenol sodium salt, and adding the obtained phenol sodium salt solution containing water to the reaction solution C8H17Vacuum dewatering in organic OH solvent, carboxylating to produce sodium salicylate, and acidifying to obtain salicylic acid. In the reaction process, the weight ratio of the organic solvent to the phenol is preferably selected to be within the range of 4-10: 1.
In addition, in the process, the molar ratio of phenol to sodium hydroxide is 1: 1.0-1.05, and the concentration of the adopted sodium hydroxide aqueous solution can be 30-50%.
The process is carried out under vacuum degree of 0-0.1 Mpa and temperature of 40-140 deg.C. When the water content in the sodium salt of phenol is less than 0.3 percent, the dehydration is stopped. At this time, excess carbon dioxide may be introduced into the liquid phase to perform carboxylation reaction at a reaction pressure of 0-0.8 Mpa and a temperature of 100-190 ℃. And stopping introducing the carbon dioxide after the reaction is finished to generate the salicylic acid sodium salt. Then, cooling, adding water and standing under the protection of nitrogen, and acidifying the separated water phase to obtain the high-purity salicylic acid with the content of more than 99.55%. And the separated organic solvent containing phenol is recycled.
The reaction equation for preparing salicylic acid in the invention is as follows:
1. to produce phenol sodium salt:
phenol is a weak acid which reacts readily with alkali to form sodium phenolate and water
2. And (3) carboxylation reaction:
alkali metal salts of phenols readily undergo carboxylation with carbon dioxide to form sodium hydrocarbyl benzoates, and hydroxy benzoic acids formed with different alkali metals or at different temperatures. The reason why the present invention can orient the formation of sodium salt of ortho-hydrocarbyl benzoic acid (salicylate) is that the presence of the organic solvent is changed to a homogeneous solution for carboxylation. The reaction equation is as follows:
since the hydrogen on the hydrocarbyl group in the sodium salicylate molecule is acidic, it reacts with sodium phenolate to form disodium salicylate:
reaction of the formulae (1) + (2) gives the formula (3):
as can be seen from the reaction formula (3): the theoretical yield of salicylic acid from phenol is up to 50%, but carboxylation under pressure inhibits the formation of the disodium salt.
3. And (3) acidification reaction:
4. side reaction:
water and carbon dioxide react to form carbonic acid:
because of H2CO3Acid strength: pkal =10, Pka2= 10.2, and the hydrogen acidity strength on the hydrocarbon group in C6H5(OH) is Pka =10, so that the phenol sodium salt is easily neutralized with carbonThe acid reacts to form phenol and sodium bicarbonate:
from the reaction equation: no water exists in the reaction system, otherwise, the phenol sodium salt is reduced into phenol, carboxylation cannot occur, and salicylic acid cannot be generated. The key problem of the process is how to completely remove the water in the sodium phenolate. The traditional Kolbe-Skhmitt method uses excessive phenol for dehydration to finally obtain dry powder of sodium phenolate, the water content of the dry powder is difficult to control in the production process, water is difficult to remove completely, local overheating and explosion are easy to occur, the reaction effect is poor, p-hydroxybenzoic acid is easy to generate, black spots exist in the product, and high-quality salicylic acid is difficult to obtain.
The invention selects an organic solvent with good effect, which is dissolved with sodium phenolate to form uniform transparent liquid, and the organic solvent is dehydrated in liquid phase, with good effect, and can dehydrate water in a reaction system to 0.02-0.3%. Carboxylation in liquid phase has high reaction selectivity, can directionally generate salicylic acid, and can recycle the solvent easily. The whole reaction process has no local overheating, the carboxylation reaction is a gas-liquid two-phase reaction, the traditional solid phase reaction is replaced by a liquid phase reaction, the carboxylation reaction speed is high, the selectivity is good, the total yield is high, and the solvent is easy to recover and reuse. The reaction process is a sealed circulation system, basically has no pollution, and is a new method suitable for industrial continuous production of salicylic acid.
Compared with the prior art, the invention has the following advantages: the reaction system 1 is easy to dehydrate, the sodium phenolate after dehydration 2 is homogeneous transparent liquid, and the water content of 3 is 0.02-0.03%. The 4 carboxylation reaction is a gas-liquid two-phase reaction, the reaction speed is high, and the reaction time is 4-6 hours. 5 reaction selectivity is good, salicylic acid can be directionally generated, and the p-hydroxybenzoic acid is basically not generated. The 6-carboxylation reaction can be carried out under normal pressure or under pressure. The solvent 7 is easy to recover, phenol and the solvent are recycled together in the reaction process, and the total recovery rate of the reaction is high and is more than 95 percent. 8, the product quality is high, the product meets the pharmaceutical grade standard, and the content is 99.56 percent. 9 the process is simple, safe in production, low in production cost, short in reaction time and suitable for large-scale continuous production. The process can adopt closed cycle production, the phenol is recycled, no discharge is generated, and three wastes are basically not generated. Salicylic acid product analysis
In the UK of China, the invention has salicylic acid content of more than 99.599.5-101 and more than 99.5 phenol content of more than 0.100.03 chloride of more than 0.014 of more than 0.0100.002 ignition residue of more than 0.10 and more than 0.05 and more than 0.10.007 heavy metal (pb) of more than 0.001 and more than 0.002 and more than 0.0020.001 sulfate of more than 0.020 and more than 0.0200.01 melting point range of 158 ℃161158-
The invention will be further described in detail with reference to the following examples:
FIG. 1 is a schematic view of the production process of the present invention.
The first embodiment is as follows:
in a 5000 ml four-hole glass reaction bottle with a stirrer and a moisture separator, 235 g (2.5 g molecule) of phenol is firstly added under the protection of nitrogen, 40 percent NaOH285 g (2.75 molecule) is slowly added with stirring, and then octanol (C) is added8H17OH)1900 g, controlling vacuum degree at 0.08 Mpa, heating to 73 deg.C, discharging water, sampling at 136 deg.C to analyze water content at 0.02%, free phenol content at 0.0802% (chromatography), cooling to 100 deg.CWhile introducing excess dry CO2Carrying out carboxylation reaction at 185 deg.C for 5 hr, stopping reaction, and cooling to room temperatureAdding 1500 ml of distilled water at 100 ℃ to dissolve the salicylic acid sodium salt, standing, separating out a water phase and an oil phase, recycling the oil phase, decoloring the water phase, acidifying with 30% sulfuric acid, stopping adding acid when the pH =2, cooling, filtering to obtain crude salicylic acid (the content is 97.5%), and recrystallizing with water to obtain 185 g of salicylic acid with the content of 99.83% (liquid chromatography analysis). The single-pass yield is: 53.9%, total yield based on phenol consumed was 96%.
Example two:
firstly, 1.4 kg of phenol is added into a mixer, 19.9 kg of octanol serving as a solvent is recovered, wherein 1.887 kg (20.07 g molecules) of phenol is added into 0.487 kg of phenol, 40 percent of NaOH 2.05 kg (20.05 g molecules) is added into the mixture under stirring, the mixture is put into a 30-liter stainless steel reaction kettle under the protection of nitrogen, the temperature is raised under stirring, the vacuum degree is controlled to be 0.09 Mpa, and water begins to flow out when the temperature reaches 58 ℃. Samples were taken for analysis when the temperature rose to 136 ℃: the content of phenol is 0.01 percent, the content of water is 0.12 percent, the materials are cooled to 110 ℃, and CO of 0.4-0.6 Mpa is mixed under stirring2Drying, introducing into a reaction kettle for carboxylation reaction at 185 deg.C,and absorbing CO2When the amount meets the requirement and sampling analysis is qualified, cooling to 100 ℃ in the presence of nitrogen, adding 10 kilograms of water, stirring for five minutes, standing, and separating out a water phase and an oil phase, wherein the refining method of the water phase is the same as that of the first embodiment. 0.927 kg of salicylic acid with the content of 99.56 percent is obtained, the once-through yield is 49.1 percent, and the total yield of the salicylic acid is 94 percent according to the consumed phenol.
Claims (7)
1. A process for preparing salicylic acid by solvent method includes such steps as neutralizing phenol with aqueous solution of sodium hydroxide to obtain sodium phenolate, and dissolving in water8H17Vacuum dewatering in organic OH solvent, carboxylating to produce sodium salicylate, and acidifying to obtain salicylic acid.
2. The process according to claim 1, wherein the weight ratio of the organic solvent to phenol is 4-10: 1.
3. The process as claimed in claim 1, wherein the molar ratio of phenol to sodium hydroxide is 1: 1.0-1.05, and the concentration of the aqueous sodium hydroxide solution is 30-50%.
4. The process according to claim 1 or 2, characterized in that after the organic solvent is added, the process is carried out under vacuum at a vacuum degree of 0-0.1 Mpa and a temperature of 40-140 ℃, and the dehydration is terminated when the water content in the phenol sodium salt is less than 0.3%.
5. The process as claimed in claim 4, wherein the carboxylation reaction of dehydrated sodium phenolate with excessive carbon dioxide is carried out at a reaction pressure of 0-0.8 MPa and a temperature of 100-190 ℃ to produce sodium salicylate, and then the introduction of carbon dioxide is stopped.
6. The process as claimed in claim 1 or 5, wherein the carboxylation reaction is carried out by cooling, adding water, standing under nitrogen protection, and acidifying the separated water phase to obtain salicylic acid.
7. The process according to claim 6, wherein the organic solvent containing phenol separated by standing after the carboxylation reaction is recovered and reused.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00123036A CN1119314C (en) | 2000-09-25 | 2000-09-25 | Process for preparing salicylic acid by solvent method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00123036A CN1119314C (en) | 2000-09-25 | 2000-09-25 | Process for preparing salicylic acid by solvent method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1289760A true CN1289760A (en) | 2001-04-04 |
| CN1119314C CN1119314C (en) | 2003-08-27 |
Family
ID=4589517
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN00123036A Expired - Fee Related CN1119314C (en) | 2000-09-25 | 2000-09-25 | Process for preparing salicylic acid by solvent method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1119314C (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100355719C (en) * | 2004-06-04 | 2007-12-19 | 北京清华紫光英力化工技术有限责任公司 | Salicylic acid preparing process |
| CN102584539A (en) * | 2011-01-06 | 2012-07-18 | 萍乡市飞虎炭黑有限公司 | Phenol sodium salt treatment method and device |
| CN102690195A (en) * | 2012-03-06 | 2012-09-26 | 江苏添鑫生物工程有限公司 | Para-hydroxybenzoic acid continuous production technique by liquid-phase method |
| CN103073394A (en) * | 2013-02-01 | 2013-05-01 | 河北敬业化工股份有限公司 | Method for producing phenol from salicylic acid sublimation residue |
| CN105878118A (en) * | 2016-05-21 | 2016-08-24 | 广州丹奇日用化工厂有限公司 | Method for extracting cedrela sinensis extract from cedrela sinensis leaves and application of method |
| CN107963963A (en) * | 2017-12-06 | 2018-04-27 | 江西省隆南药化有限公司 | A kind of preparation method of septichen |
| CN110041189A (en) * | 2019-04-28 | 2019-07-23 | 东南大学 | It is a kind of to prepare salicylic technique using microchannel continuous flow reactor |
| 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 |
| CN113416137A (en) * | 2021-06-22 | 2021-09-21 | 宁夏万香源生物科技有限公司 | Preparation method of benzyl salicylate |
| CN114345285A (en) * | 2022-01-12 | 2022-04-15 | 青岛科技大学 | Continuous production process of sodium salicylate solution |
| CN114805060A (en) * | 2022-06-13 | 2022-07-29 | 扬州大学 | Preparation method of potassium parahydroxybenzoate |
| CN115010599A (en) * | 2022-06-13 | 2022-09-06 | 扬州大学 | Method for separating and refining salicylic acid from sodium salicylate acidized material |
| CN116267989A (en) * | 2022-09-09 | 2023-06-23 | 兰州大学 | Nanometer iron antibacterial agent for fusarium trilineum |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2718932B2 (en) * | 1988-01-23 | 1998-02-25 | 株式会社上野製薬応用研究所 | Method for producing aromatic oxycarboxylic acid |
-
2000
- 2000-09-25 CN CN00123036A patent/CN1119314C/en not_active Expired - Fee Related
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100355719C (en) * | 2004-06-04 | 2007-12-19 | 北京清华紫光英力化工技术有限责任公司 | Salicylic acid preparing process |
| CN102584539A (en) * | 2011-01-06 | 2012-07-18 | 萍乡市飞虎炭黑有限公司 | Phenol sodium salt treatment method and device |
| CN102690195A (en) * | 2012-03-06 | 2012-09-26 | 江苏添鑫生物工程有限公司 | Para-hydroxybenzoic acid continuous production technique by liquid-phase method |
| CN102690195B (en) * | 2012-03-06 | 2015-02-18 | 江苏添鑫生物工程有限公司 | Para-hydroxybenzoic acid continuous production technique by liquid-phase method |
| CN103073394A (en) * | 2013-02-01 | 2013-05-01 | 河北敬业化工股份有限公司 | Method for producing phenol from salicylic acid sublimation residue |
| CN103073394B (en) * | 2013-02-01 | 2015-07-29 | 河北敬业化工股份有限公司 | A kind of method of being produced phenol by salicylic acid sublimation residue |
| CN105878118A (en) * | 2016-05-21 | 2016-08-24 | 广州丹奇日用化工厂有限公司 | Method for extracting cedrela sinensis extract from cedrela sinensis leaves and application of method |
| CN107963963A (en) * | 2017-12-06 | 2018-04-27 | 江西省隆南药化有限公司 | A kind of preparation method of septichen |
| CN110041189A (en) * | 2019-04-28 | 2019-07-23 | 东南大学 | It is a kind of to prepare salicylic technique using microchannel continuous flow reactor |
| 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 |
| CN113416137A (en) * | 2021-06-22 | 2021-09-21 | 宁夏万香源生物科技有限公司 | Preparation method of benzyl salicylate |
| CN113416137B (en) * | 2021-06-22 | 2024-01-02 | 宁夏万香源生物科技有限公司 | Preparation method of benzyl salicylate |
| CN114345285A (en) * | 2022-01-12 | 2022-04-15 | 青岛科技大学 | Continuous production process of sodium salicylate solution |
| CN114345285B (en) * | 2022-01-12 | 2023-09-08 | 青岛科技大学 | Continuous production process of sodium salicylate solution |
| CN114805060A (en) * | 2022-06-13 | 2022-07-29 | 扬州大学 | Preparation method of potassium parahydroxybenzoate |
| CN115010599A (en) * | 2022-06-13 | 2022-09-06 | 扬州大学 | Method for separating and refining salicylic acid from sodium salicylate acidized material |
| CN115010599B (en) * | 2022-06-13 | 2024-01-09 | 扬州大学 | Method for separating and refining salicylic acid from sodium salicylate acidified material |
| CN116267989A (en) * | 2022-09-09 | 2023-06-23 | 兰州大学 | Nanometer iron antibacterial agent for fusarium trilineum |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1119314C (en) | 2003-08-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1289760A (en) | Process for preparing salicylic acid by solvent method | |
| CN108715574B (en) | Method for synthesizing biphenol | |
| US11524928B2 (en) | Method for preparation of 2,5-dimethylphenol by selective catalytic conversion of lignin | |
| US20210198108A1 (en) | Continuos process for producing insoluble sulfur | |
| CN1297531C (en) | Novel supercritical phase salicylic acid synthesis process | |
| CN111359659A (en) | Catalyst for synthesizing tertiary carboxylic acid, application of catalyst and synthetic method of tertiary carboxylic acid | |
| CN109400650B (en) | Synthesis method of flame retardant DOPO-ITA | |
| US20010023303A1 (en) | Method for recovery of terephthalic acid from a material containing poly (ethylene terephthalates) | |
| CN1214002C (en) | Process for synthesizing hydrate of calcium phenolsulfonate | |
| KR870000245B1 (en) | Process for the preparation of 2-hydroxy naphthalene-6-carboxylic acid | |
| CN111825590A (en) | Preparation method of tert-butyl peroxybenzoate | |
| CN106632533A (en) | Low-temperature and efficient preparation method of sucrose-6-acetate | |
| CN1883729A (en) | Method for processing rectified residue of ketene dimer | |
| CN101830820A (en) | Method for preparing 2,5-diparamethylaniline terephthalic acid (DTTA) | |
| US6326521B2 (en) | Process for the preparation of benzyl alcohol | |
| KR920005816B1 (en) | Process for producing aromatic hydroxycarboxylic acid | |
| CN115385363A (en) | Method for separating potassium fluoride and potassium chloride by using mixed alcohol reagent | |
| CN1068818A (en) | A kind of production method of antioxidant | |
| CN113402381A (en) | Preparation method of chloroacetyl chloride | |
| CN1394843A (en) | Solvent-free new synthesis process for simultaneously producing 2,4-dihydroxybenzoic acid and 2,6-diydroxybenzoic acid | |
| CN1868995A (en) | Separation method of o-chlorobenzoic acid and p-chlorobenzoic acid mixture | |
| CA1120055A (en) | Process for producing carboxylic acids and aromatic carboxylic acids | |
| CN220940689U (en) | Device for preparing polyaluminum chloride by reaction of light-burned kaolin and hydrochloric acid | |
| CN113912486B (en) | Preparation method of dicyclopentadiene dicarboxylate | |
| CN114874080B (en) | Preparation method of 4,4' -difluorobenzophenone |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |