CN112516925A - Reaction device for p-hydroxybenzoic acid and preparation method thereof - Google Patents
Reaction device for p-hydroxybenzoic acid and preparation method thereof Download PDFInfo
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- CN112516925A CN112516925A CN202011330416.1A CN202011330416A CN112516925A CN 112516925 A CN112516925 A CN 112516925A CN 202011330416 A CN202011330416 A CN 202011330416A CN 112516925 A CN112516925 A CN 112516925A
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- phenol
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- hydroxybenzoic acid
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- FJKROLUGYXJWQN-UHFFFAOYSA-N 4-hydroxybenzoic acid Chemical compound OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 60
- 229940090248 4-hydroxybenzoic acid Drugs 0.000 title claims abstract description 34
- 238000002360 preparation method Methods 0.000 title abstract description 12
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 106
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 54
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 53
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000007787 solid Substances 0.000 claims abstract description 43
- 238000006473 carboxylation reaction Methods 0.000 claims abstract description 13
- OHEPMXOERTVRMN-UHFFFAOYSA-L dipotassium;4-carboxyphenolate Chemical compound [K+].[K+].OC(=O)C1=CC=C([O-])C=C1.OC(=O)C1=CC=C([O-])C=C1 OHEPMXOERTVRMN-UHFFFAOYSA-L 0.000 claims abstract description 12
- 238000007065 Kolbe-Schmitt synthesis reaction Methods 0.000 claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 13
- 239000002245 particle Substances 0.000 claims description 9
- 238000003860 storage Methods 0.000 claims description 9
- 239000000428 dust Substances 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 4
- 238000009835 boiling Methods 0.000 claims description 3
- 239000006185 dispersion Substances 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims description 2
- 159000000000 sodium salts Chemical class 0.000 claims description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-M phenolate Chemical compound [O-]C1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-M 0.000 claims 4
- 229940031826 phenolate Drugs 0.000 claims 2
- 230000005494 condensation Effects 0.000 claims 1
- 238000009833 condensation Methods 0.000 claims 1
- ZGJADVGJIVEEGF-UHFFFAOYSA-M potassium;phenoxide Chemical compound [K+].[O-]C1=CC=CC=C1 ZGJADVGJIVEEGF-UHFFFAOYSA-M 0.000 abstract description 19
- 230000008901 benefit Effects 0.000 abstract description 6
- 239000011343 solid material Substances 0.000 description 9
- RKHQZMOCQHXUBC-UHFFFAOYSA-N phenol;potassium Chemical compound [K].OC1=CC=CC=C1 RKHQZMOCQHXUBC-UHFFFAOYSA-N 0.000 description 6
- 238000007599 discharging Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 150000002989 phenols Chemical class 0.000 description 2
- DKGFIVSGQRBSOG-UHFFFAOYSA-M potassium;4-hydroxybenzoate Chemical compound [K+].OC1=CC=C(C([O-])=O)C=C1 DKGFIVSGQRBSOG-UHFFFAOYSA-M 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical class [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000021523 carboxylation Effects 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- KCIDZIIHRGYJAE-YGFYJFDDSA-L dipotassium;[(2r,3r,4s,5r,6r)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl] phosphate Chemical compound [K+].[K+].OC[C@H]1O[C@H](OP([O-])([O-])=O)[C@H](O)[C@@H](O)[C@H]1O KCIDZIIHRGYJAE-YGFYJFDDSA-L 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 239000002304 perfume Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- PYOZTOXFQNWBIS-UHFFFAOYSA-N phenol;sodium Chemical compound [Na].OC1=CC=CC=C1 PYOZTOXFQNWBIS-UHFFFAOYSA-N 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
- B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
- B01J3/002—Component parts of these vessels not mentioned in B01J3/004, B01J3/006, B01J3/02 - B01J3/08; Measures taken in conjunction with the process to be carried out, e.g. safety measures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
- B01J3/04—Pressure vessels, e.g. autoclaves
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/02—Preparation of carboxylic acids or their salts, halides or anhydrides from salts of carboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/15—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/41—Preparation of salts of carboxylic acids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
- B01D46/16—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces arranged on non-filtering conveyors or supports
Abstract
The invention discloses a reaction device for p-hydroxybenzoic acid and a preparation method thereof, wherein the preparation method comprises the following steps: continuously feeding the solid of the potassium phenolate and carbon dioxide gas into a fluidized bed reactor, carrying out Kolbe-Schmitt carboxylation reaction to generate dipotassium p-hydroxybenzoate and phenol, taking the phenol out of the fluidized bed reactor by carbon dioxide gas flow, and condensing and recovering the phenol by a condenser; the carbon dioxide gas stream is circulated through the fan. The reaction device has the characteristics of higher reaction selectivity and higher yield, and has the advantage of simple equipment compared with gas-liquid-solid heterogeneous reaction.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a reaction device for p-hydroxybenzoic acid and a preparation method thereof.
Background
Para-hydroxybenzoic acid is an important organic chemical intermediate, and downstream products thereof are widely used in the industries of medicines, pesticides, dyes, cosmetics, perfumes and high molecular materials. The industrial preparation of p-hydroxybenzoic acid is mainly achieved by Kolbe-Schmitt carboxylation. Under certain reaction temperature and pressure conditions, a phenol metal salt such as potassium phenol salt or sodium phenol salt and carbon dioxide gas undergo carboxylation reaction to generate hydroxybenzoic acid; at lower temperatures (below 200 ℃ C.) mainly o-hydroxybenzoic acid is formed, and at higher temperatures mainly p-hydroxybenzoic acid is formed (EP 478197).
The carboxylation reaction of potassium phenolate and carbon dioxide gas at high temperature to produce p-hydroxybenzoic acid is shown as the following formula:
because phenol is slightly more acidic than the monopotassium p-hydroxybenzoate, the phenol produced by the reaction exchanges with the dipotassium p-hydroxybenzoate to produce monopotassium p-hydroxybenzoate:
the monopotassium salt of parahydroxybenzoic acid is easily decomposed at high temperature, and the decomposition is further promoted by the presence of phenol (journal of Industrial chemistry, 64,1624 (1961)). Therefore, the phenol produced by the reaction is removed in time, which would otherwise affect the yield.
There are two types of gas-solid heterogeneous reaction and gas-liquid-solid heterogeneous reaction for industrially producing p-hydroxybenzoic acid. The gas-solid heterogeneous reaction is carried out in a pressure vessel with stirring in intermittent operation, and under the limited action of a stirrer, solid materials such as potassium phenolate solid, dipotassium p-hydroxybenzoate solid and carbon dioxide gas are easy to aggregate and agglomerate, are heated unevenly, have uneven temperature distribution and poor mass and heat transfer effects, and sometimes even decompose and resinify the materials; phenol generated by the reaction cannot be removed in time; these factors all affect reaction selectivity and yield.
In order to solve the problem of poor solid dispersibility of gas-solid heterogeneous reaction carried out in a pressure vessel with stirring in batch operation, potassium phenoxide solid is suspended in a solvent to react with carbon dioxide gas, namely gas-liquid-solid heterogeneous reaction. Suitable solvents are kerosene, light oils, etc. (EP 478197; CN 102690195). This gas-liquid-solid heterogeneous reaction can be carried out in a pressure stirred tank; it may be operated continuously or intermittently. The disadvantage of this process is that the separation and recovery of the solvent requires complex processes and equipment.
Disclosure of Invention
The above-mentioned techniques have many drawbacks such as gas-solid heterogeneous reaction in a pressure vessel with stirring in batch operation, poor dispersion of solid, poor effect of mass and heat transfer, and inability of timely removal of phenol formed by the reaction; the separation and recovery of the solvent by gas-liquid-solid heterogeneous reaction is difficult. In order to solve the defects of the prior art, the invention provides a reaction device for p-hydroxybenzoic acid and a preparation method thereof.
The technical scheme adopted by the invention for solving the problems is as follows: a reaction device for p-hydroxybenzoic acid comprises a heater 9, a fluidized bed reactor 4, a condenser 6, a phenol storage tank 7 and a fan 8; a gas distributor 10 and a dust removal device 3 are arranged in the fluidized bed reactor 4 to prevent the carbon dioxide gas flow from carrying the solid p-hydroxybenzoic acid dipotassium salt to leave the fluidized bed reactor 4; the barrel of the boiling bed reactor 4 is provided with a jacket which can keep the temperature and assist in providing heating.
Further, a scraper type stirrer is arranged in the region, close to the gas distributor 10, inside the fluidized bed reactor 4, so that the dispersibility of solid powder is fully guaranteed, dead angles of the solid powder are avoided, and the operability of the fluidized bed reactor 4 can be guaranteed.
Further, the reaction apparatus may be operated continuously or intermittently. Wherein, the continuous operation refers to gas circulation and continuous feeding and discharging of solid materials. The intermittent operation refers to gas circulation and one-time feeding and one-time discharging of solid materials.
Another object of the present invention is to provide a method for preparing parahydroxybenzoic acid according to the above reaction apparatus, comprising: and continuously feeding the metal phenol salt and carbon dioxide gas into the fluidized bed reactor 4, suspending the metal phenol salt in the carbon dioxide gas flow, and carrying out Kolbe-Schmitt carboxylation reaction to generate dipotassium p-hydroxybenzoate and phenol.
Further, the metal salt of phenol is any one of potassium salt of phenol and sodium salt of phenol.
Further, the metal phenate is a powdery metal phenate solid with the average particle diameter of 20-120 meshes, and is dried to be anhydrous and free of alkali, so that most of the metal phenate can be suspended in a carbon dioxide gas flow.
Further, the carbon dioxide gas is heated by a heater 9 and enters the fluidized bed reactor 4 through a gas distributor 10, and the powdery phenol metal salt solid enters through a feeding valve 2 and rolls up and down in the carbon dioxide gas flow.
Further, the phenol is carried out by a carbon dioxide gas flow, condensed by a condenser 6 and recovered. The phenol generated in the reaction is removed from the reactor in time, so that the selectivity and yield of the carboxylation reaction can be improved.
Further, the empty bed gas velocity of the carbon dioxide gas flow is 0.2-1.0 m/s, and the carbon dioxide gas flow is circulated by the fan 8. Wherein the flow rate of the carbon dioxide gas is controlled so that the potassium phenolate solid and the dipotassium parabenate solid are suspended in the carbon dioxide gas stream and are not entrained by the carbon dioxide gas stream.
Furthermore, the reaction temperature of the Kolbe-Schmitt carboxylation reaction is 200-300 ℃, the reaction pressure is 0.3-2.0 MPa, and the heat and the temperature required by the reaction are provided by a heater 9.
Furthermore, the reaction temperature of the Kolbe-Schmitt carboxylation reaction is 250-270 ℃, and the reaction pressure is 0.5-1.0 MPa.
The invention has the advantages that:
compared with gas-solid heterogeneous reaction carried out in a pressure vessel with stirring, the invention has the following advantages: because the solid particles move violently and roll up and down, the relative speed of the solid particles and the carbon dioxide gas is high, the influence of external diffusion is eliminated, the mass and heat transfer effects are good, and the temperature distribution is uniform; in addition, phenol can be removed in time, so that the reaction is promoted, and side reactions are reduced. Therefore, the carboxylation reaction has high selectivity and high yield, and compared with gas-liquid-solid heterogeneous reaction, the method has the advantage of simple equipment.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:
FIG. 1 is a schematic flow diagram of a reaction apparatus for carrying out the reaction of parahydroxybenzoic acid according to the present invention.
List of reference numerals: the system comprises a phenol metal salt storage tank 1, a feed valve 2, a dust removal device 3, a fluidized bed reactor 4, a discharge valve 5, a condenser 6, a phenol storage tank 7, a fan 8, a heater 9 and a gas distributor 10; a-CO2，b-N2。
Detailed Description
The following detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.
Example 1
Reaction device for p-hydroxybenzoic acid and preparation method thereof
The carbon dioxide gas is heated to 250-270 ℃ by a heater 9 and enters the fluidized bed reactor 4 through a gas distributor 10; powdery potassium phenolate solid with the average particle diameter of 20-120 meshes enters a fluidized bed reactor 4 through a feeding valve 2, rolls up and down in carbon dioxide airflow, and undergoes Kolbe-Schmitt carboxylation reaction to generate dipotassium p-hydroxybenzoate and phenol; controlling the flow rate of the carbon dioxide gas, wherein the air speed of an empty bed is usually 0.2-1.0 m/s, so that the powdery potassium phenolate solid and the solid dipotassium p-hydroxybenzoate can be suspended in the carbon dioxide gas flow and cannot be taken away by the carbon dioxide gas flow. The lower part of the boiling bed reactor 4 is a dense phase area, the density of solid particles is high, and the dense phase area is a main reaction area; the upper part of the fluidized bed reactor 4 is a dilute phase region, the density of solid particles is small, the particle size is also small, and carbon dioxide gas which is going to leave the fluidized bed reactor 4 is collected by a dust removal device 3 such as a cyclone separator or a filter stick dust remover; the phenol is taken out by the carbon dioxide gas flow, condensed by a condenser 6 and then enters a phenol storage tank 7; the carbon dioxide gas stream is circulated by fan 8.
Example 2
Reaction device for p-hydroxybenzoic acid and preparation method thereof (intermittent operation)
In the reaction device shown in FIG. 1, carbon dioxide gas is heated to 250 ℃ by a heater 9 and enters an ebullated bed reactor 4 through a gas distributor 10; feeding powdery potassium phenolate solid with the particle diameter of 20-120 meshes into a fluidized bed reactor 4 through a feeding valve 2, and rolling up and down in carbon dioxide airflow to perform Kolbe-Schmitt carboxylation reaction to generate dipotassium p-hydroxybenzoate and phenol; the phenol is taken out by the carbon dioxide gas flow, condensed by a condenser 6 and then enters a phenol storage tank 7; the carbon dioxide gas stream is circulated by fan 8.
Wherein, 100 parts by mass of potassium phenoxide is fed, the operation temperature of the fluidized bed reactor 4 is 250 ℃, the operation pressure is 0.5MPa, the empty bed gas velocity of carbon dioxide gas is 0.2m/s, the reaction time is 2 hours, and 52.3 parts by mass of p-hydroxybenzoic acid with the content of 99.2 percent and the conversion rate of the potassium phenoxide of 99 percent are obtained by sampling and analyzing through a discharge valve 5.
Example 3
Reaction device for p-hydroxybenzoic acid and preparation method thereof (continuous operation)
On the basis of the embodiment 2, continuous feeding and continuous discharging are started, wherein 50 parts (by mass) of potassium phenolate per hour is continuously fed, and phenol is taken out by a carbon dioxide gas flow, condensed by a condenser 6 and then enters a phenol storage tank 7; circulating carbon dioxide gas flow through a fan 8, and acidifying and separating the dipotassium p-hydroxybenzoate discharged from the fluidized bed reactor 4 to obtain the p-hydroxybenzoic acid; wherein the operation temperature is 270 ℃, the operation pressure is 1.0MPa, the empty bed gas velocity of carbon dioxide gas is 1.0m/s, the retention time of solid materials is 1.5 hours, the solid materials are continuously discharged through a discharge valve 5, 26.2 parts (by mass) of p-hydroxybenzoic acid with the content of 99.0 percent is obtained every hour, and the conversion rate of phenol potassium salt is 99 percent.
Example 4
Reaction device for p-hydroxybenzoic acid and preparation method thereof (continuous operation)
On the basis of the embodiment 2, continuous feeding and continuous discharging are started, wherein 50 parts (by mass) of potassium phenolate per hour is continuously fed, and phenol is taken out by a carbon dioxide gas flow, condensed by a condenser 6 and then enters a phenol storage tank 7; circulating carbon dioxide gas flow through a fan 8, and acidifying and separating the dipotassium p-hydroxybenzoate discharged from the fluidized bed reactor 4 to obtain the p-hydroxybenzoic acid; wherein the operation temperature is 200 ℃, the operation pressure is 0.3MPa, the empty bed gas velocity of carbon dioxide gas is 0.5m/s, the solid material stays for 1 hour, and the solid material is continuously discharged through a discharge valve 5, wherein 26.1 parts (by mass) of p-hydroxybenzoic acid with the content of 99.0 percent and the conversion rate of phenol potassium salt is 99 percent are obtained every hour.
Example 5
Reaction device for p-hydroxybenzoic acid and preparation method thereof (continuous operation)
On the basis of the embodiment 2, continuous feeding and continuous discharging are started, wherein 50 parts (by mass) of potassium phenolate per hour is continuously fed, and phenol is taken out by a carbon dioxide gas flow, condensed by a condenser 6 and then enters a phenol storage tank 7; circulating carbon dioxide gas flow through a fan 8, and acidifying and separating the dipotassium p-hydroxybenzoate discharged from the fluidized bed reactor 4 to obtain the p-hydroxybenzoic acid; wherein the operation temperature is 300 ℃, the operation pressure is 2MPa, the empty bed gas velocity of the carbon dioxide gas is 0.6m/s, the solid material stays for 2 hours, and the solid material is continuously discharged through a discharge valve 5, 25.8 parts (by mass) of p-hydroxybenzoic acid with the content of 99.0 percent is obtained every hour, and the conversion rate of the phenol potassium salt is 98 percent.
Comparative example 1
The gas-solid heterogeneous reaction is carried out in a pressure vessel with a screw-type stirrer operated intermittently. Reacting the solid potassium phenolate at the temperature of 250-270 ℃ for 4-6 hours under the pressure of 0.5-1.0 MPa carbon dioxide, and acidifying to obtain the p-hydroxybenzoic acid with the content of 98.0% and the conversion rate of the potassium phenolate of 70-75%.
Comparative example 2
The gas-solid heterogeneous reaction is carried out in a pressure vessel with a screw-type stirrer operated intermittently. 100 parts by mass of solid potassium phenoxide was reacted at 250 ℃ for 2 hours under 0.5MPa of carbon dioxide pressure, and after acidification treatment, 37.3 parts by mass of p-hydroxybenzoic acid was obtained, the content of which was 98.0%, and the conversion rate of potassium phenoxide was 70%.
Comparative example 3
The gas-solid heterogeneous reaction is carried out in a pressure vessel with a screw-type stirrer operated intermittently. Reacting the solid potassium phenolate at the carbon dioxide pressure of 0.5-1.0 MPa at the temperature of 250-270 ℃ for 4-6 hours; pressure is relieved, and phenol is distilled off; continuously reacting for 2-3 hours at the temperature of 250-270 ℃ under the pressure of carbon dioxide of 0.5-1.0 MPa; and (3) decompressing, distilling off phenol, and reacting for 2-3 hours to obtain p-hydroxybenzoic acid with the content of 98.0% and the conversion rate of phenol potassium salt of 75-80%.
Comparative example 4
The gas-solid heterogeneous reaction is carried out in a pressure vessel with a screw-type stirrer operated intermittently. Feeding 100 parts (mass) of phenol potassium salt solid under the pressure of 0.5MPa of carbon dioxide and at the temperature of 250 ℃ for 5 hours; pressure is relieved, and phenol is distilled off; continuously reacting for 2 hours at 250 ℃ under the pressure of 0.5MPa of carbon dioxide; the pressure was released, phenol was distilled off, and the reaction was continued for 2 hours to obtain 42.7 parts by mass of p-hydroxybenzoic acid in an amount of 98.0% with a potassium phenoxide conversion of 80%.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The reaction device for p-hydroxybenzoic acid is characterized by comprising a heater (9), a fluidized bed reactor (4), a condenser (6), a phenol storage tank (7) and a fan (8); a gas distributor (10) and a dust removal device (3) are arranged in the fluidized bed reactor (4); the barrel of the boiling bed reactor (4) is provided with a jacket, so that heat can be preserved and heating can be provided in an auxiliary manner.
2. The p-hydroxybenzoic acid reaction device according to claim 1, wherein a scraper-type stirrer is arranged inside the fluidized bed reactor (4) near the gas distributor (10) to fully ensure the dispersion of the solid powder and avoid dead corners of the solid powder.
3. The reaction device of p-hydroxybenzoic acid according to claim 1, wherein the reaction device can be operated continuously or intermittently.
4. A method for preparing hydroxybenzoic acid according to any one of claims 1 to 3, wherein the method comprises: and continuously feeding the metal phenolate and carbon dioxide gas into the fluidized bed reactor (4), suspending the metal phenolate in a carbon dioxide gas flow, and carrying out Kolbe-Schmitt carboxylation reaction to generate dipotassium p-hydroxybenzoate and phenol.
5. The method according to claim 4, wherein the metal salt of phenol is any one of potassium salt of phenol and sodium salt of phenol.
6. The method according to claim 4, wherein the metal phenoxide is a powdery metal phenoxide solid having an average particle diameter of 20 to 120 mesh.
7. The method for preparing hydroxybenzoic acid according to claim 4, wherein the carbon dioxide gas is heated by the heater (9) and enters the ebullated-bed reactor (4) through the gas distributor (10).
8. The method according to claim 4, wherein the phenol is recovered by condensation in a condenser (6) carried out by a carbon dioxide stream.
9. The method according to claim 4, wherein the empty bed gas velocity of the carbon dioxide gas stream is 0.2-1.0 m/s.
10. The method for preparing p-hydroxybenzoic acid according to claim 4, wherein the Kolbe-Schmitt carboxylation reaction is carried out at a temperature of 200 ℃ to 300 ℃ and a pressure of 0.3MPa to 2.0 MPa.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113698286A (en) * | 2021-09-16 | 2021-11-26 | 宿迁思睿屹新材料有限公司 | Preparation method of p-hydroxybenzoic acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4508920A (en) * | 1982-03-23 | 1985-04-02 | Bayer Aktiengesellschaft | Process for the preparation of aromatic hydroxycarboxylic acids |
| CN111482146A (en) * | 2020-04-17 | 2020-08-04 | 中国石油化工股份有限公司 | Three-phase separator, three-phase reactor and three-phase reaction method |
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2020
- 2020-11-24 CN CN202011330416.1A patent/CN112516925A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4508920A (en) * | 1982-03-23 | 1985-04-02 | Bayer Aktiengesellschaft | Process for the preparation of aromatic hydroxycarboxylic acids |
| CN111482146A (en) * | 2020-04-17 | 2020-08-04 | 中国石油化工股份有限公司 | Three-phase separator, three-phase reactor and three-phase reaction method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113698286A (en) * | 2021-09-16 | 2021-11-26 | 宿迁思睿屹新材料有限公司 | Preparation method of p-hydroxybenzoic acid |
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