CN216799781U - Continuous production device of 2-methyl-3-hydroxybenzoic acid - Google Patents
Continuous production device of 2-methyl-3-hydroxybenzoic acid Download PDFInfo
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- CN216799781U CN216799781U CN202220209852.1U CN202220209852U CN216799781U CN 216799781 U CN216799781 U CN 216799781U CN 202220209852 U CN202220209852 U CN 202220209852U CN 216799781 U CN216799781 U CN 216799781U
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Abstract
The present disclosure relates to a continuous production apparatus of 2-methyl-3-hydroxybenzoic acid, comprising a batching unit, a conveying unit, a diazotization reaction unit and a hydrolysis reaction unit which are connected in sequence; the reactor used by the diazotization reaction unit comprises one of a dynamic tubular reactor, a dynamic tubular reactor series static tubular reactor and a dynamic tubular reactor series kettle reactor. The continuous production device provided by the disclosure uses 2-methyl-3-aminobenzoic acid as a raw material, can be used for continuous and safe production, and can be used for directly producing high-purity products.
Description
Technical Field
The disclosure relates to the technical field of compound production devices, in particular to a continuous production device of 2-methyl-3-hydroxybenzoic acid.
Background
2-methyl-3-hydroxybenzoic acid is an important intermediate for preparing medicines and agricultural chemicals, and the traditional process is prepared by heating 1,3, 5-trisulfonic acid or a salt thereof in the presence of alkali metal hydroxide; or heating 3-aminonaphthalene-1, 5-disulfonic acid sodium hydrogen and sodium hydroxide with twice weight equivalent under the pressure of 40bar and the temperature of 275-280 ℃, and filtering and acidifying after cooling a reaction mixture to prepare the product, wherein the process is complex, the conditions are harsh, the production device is very complex, and the cost is high; after the process is improved, 2-methyl-3-aminobenzoic acid can be used as a raw material to prepare 2-methyl-3-hydroxybenzoic acid through diazotization and hydrolysis, at present, a kettle type reactor device is adopted in industrial production of the method, the purity of the obtained product is low, matched refining equipment is needed for sale or downstream application, and continuous production cannot be completely realized, so that a device capable of realizing continuous, safe and stable production of high-purity 2-methyl-3-benzoic acid is very necessary.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the present disclosure provides a continuous production apparatus of 2-methyl-3-hydroxybenzoic acid. The continuous production device provided by the disclosure uses 2-methyl-3-aminobenzoic acid as a raw material, can be used for continuous and safe production, and can be used for directly producing high-purity products.
The present disclosure provides a continuous production apparatus of 2-methyl-3-hydroxybenzoic acid, the apparatus comprises a batching unit, a conveying unit, a diazotization reaction unit and a hydrolysis reaction unit which are connected in sequence;
wherein the reactor used by the diazotization reaction unit comprises one of a dynamic tubular reactor, a dynamic tubular reactor series static tubular reactor and a dynamic tubular reactor series kettle type reactor.
In the continuous production device used in the present disclosure, the outlet of the batching unit is communicated with the inlet of the conveying unit, the outlet of the conveying unit is communicated with the inlet of the diazotization reaction unit, the diazo liquid outlet is communicated with the diazo liquid inlet of the hydrolysis reaction unit, a hydrolysate containing 2-methyl-3-hydroxybenzoic acid can be obtained at the outlet of the hydrolysis reaction unit, and the content of the 2-methyl-3-hydroxybenzoic acid in the hydrolysate is high.
The diazotization reaction unit is used for providing a place where raw material 2-methyl-3-aminobenzoic acid is subjected to diazotization, when the continuous production device provided by the disclosure is utilized, raw material preparation and supply are carried out in a batching unit, and the preparation method comprises the steps of mixing 2-methyl-3-aminobenzoic acid with a sulfuric acid solution (first mixed solution) and providing a sodium nitrite solution (second mixed solution), then conveying the raw material to the diazotization reaction unit by utilizing a conveying unit for diazotization reaction, and then allowing the diazotization reaction solution to enter a hydrolysis reaction unit for hydrolysis to obtain a hydrolysis solution containing 2-methyl-3-hydroxybenzoic acid. The diazotization reaction unit is provided with a first mixed solution inlet, a second mixed solution inlet and a diazotization solution outlet.
The dynamic tubular reactor is provided with a reaction cavity with a stirring shaft and a heat exchange cavity capable of being communicated with a heat exchange medium, the stirring shaft is provided with a stirring paddle which plays a role in stirring and mixing, the effective liquid holdup of the dynamic tubular reactor is 1-200L, and the adjustment range of the rotation speed of the stirring shaft is within the range of 0-500 r/min. Meanwhile, in order to further ensure the conversion rate of the raw materials, a static tubular reactor or a kettle type reactor can be connected in series at a discharge port of the dynamic tubular reactor, wherein the static tubular reactor comprises a static tubular reactor with a mixing element arranged in a channel and a static tubular reactor without the mixing element arranged in the channel, and the static tubular reactor can be a tubular static mixing reactor, a wound tubular reactor, a coil tubular reactor or a tubular reactor; the kettle type reactor is a stirring kettle with an overflow port.
The continuous reaction device is adopted, the mixed solution of 2-methyl-3-aminobenzoic acid and sulfuric acid and a sodium nitrite solution are simultaneously conveyed into the dynamic tubular reactor in the diazotization reaction stage, diazotization reaction is carried out while the two mixed solutions are rapidly mixed, the operation of reaction after mixing is avoided, the contact probability of diazotized solution and raw material can be reduced, the process is simplified, back mixing is avoided, the raw material can be fully reacted under the condition of ensuring higher reaction rate, and the occurrence of side reaction is reduced.
The diazotization reaction unit provided by the disclosure can carry out diazotization reaction at a lower temperature (0-30 ℃, preferably 5-20 ℃), and the reaction time is shorter (1-30 min, preferably 2-20 min), so that the rapid diazotization reaction of 2-methyl-3-aminobenzoic acid is realized. According to the method, the reactor used by the diazotization reaction unit is limited, so that the diazotization reaction can be carried out while the raw material is rapidly mixed with the mixed solution of 2-methyl-3-aminobenzoic acid and sulfuric acid and the sodium nitrite solution in the diazotization reaction stage, the pre-mixing process can be omitted, the process is simplified, the occurrence of side reactions can be reduced, and the purity and yield of the product are improved.
In order to remove the residual sodium nitrite in the diazo liquid, the preparation process of the 2-methyl-3-hydroxybenzoic acid should also comprise an impurity removal process, as a preferred technical scheme of the present disclosure, the continuous production device further comprises an impurity removal reaction unit positioned between the diazotization reaction unit and the hydrolysis reaction unit, the diazotization reaction unit and the hydrolysis reaction unit are connected through the impurity removal reaction unit, and in the impurity removal reaction unit, the urea solution reacts with the sodium nitrite in the diazo liquid.
The impurity removal reaction unit is provided with a diazo liquid inlet, a urea solution inlet and an impurity removed diazo liquid outlet, the diazo liquid inlet is connected with the diazo liquid outlet of the diazotization reaction unit, the impurity removed diazo liquid outlet is connected with the diazo liquid inlet of the hydrolysis reaction unit, an exhaust port is arranged on the impurity removal reaction unit, or a discharge port of the impurity removal reaction unit is connected with a gas-liquid separation device and used for discharging gas generated in the impurity removal process; as a preferred technical scheme of the present disclosure, the reactor used by the impurity removal reaction unit comprises a tank reactor or a dynamic tubular reactor.
As a preferred embodiment of the present disclosure, the continuous production apparatus further includes a separation unit connected to the hydrolysis reaction unit.
In order to obtain a 2-methyl-3-hydroxybenzoic acid product by post-treating hydrolysate containing 2-methyl-3-hydroxybenzoic acid, phase separation, extraction, concentration and drying are generally required to obtain the 2-methyl-3-hydroxybenzoic acid, and as a preferred technical scheme of the disclosure, the equipment used by the separation unit comprises an oil-water separator, an aqueous phase extraction equipment, an organic solvent recovery equipment, a sulfuric acid recovery equipment and a drying equipment.
In the process of post-treatment, the organic solvent recovered by phase separation can be recovered and reused for hydrolysis reaction, and the water phase can obtain sulfuric acid which can be used for diazotization reaction or hydrolysis reaction through processes of organic matter removal, concentration, salt removal and the like after the residual organic phase is extracted.
The oil-water separation equipment is provided with a hydrolysate inlet, an organic phase outlet and a water phase outlet, and can be a conventional oil-water separator on the market, so that continuous or intermittent separation of oil and water phases can be realized.
The water phase extraction equipment is provided with a water phase inlet, an organic solvent inlet, a post-extraction water phase outlet and a post-extraction organic phase outlet, and the water phase extraction equipment can be an extraction tower or a centrifugal extractor or other equipment capable of realizing the extraction function.
The organic solvent recovery equipment is provided with an organic phase inlet, an organic solvent outlet and a product outlet, and the organic solvent recovery equipment can select evaporation concentration equipment so as to realize the recovery of the organic solvent and obtain the product 2-methyl-3-hydroxybenzoic acid.
The equipment used by the separation unit also comprises sulfuric acid recovery equipment and drying equipment, wherein the sulfuric acid recovery equipment can select a distillation kettle or a rectifying tower to realize the concentration of sulfuric acid; the drying device can be selected from a roller dryer, a drum dryer, a film dryer or other devices capable of drying the product.
The hydrolysate outlet of the hydrolysis reaction unit is communicated with the hydrolysate inlet of the oil-water separation equipment, the water phase outlet of the oil-water separation equipment is connected with the water phase inlet of the water phase extraction equipment, and the organic phase outlet of the water phase extraction equipment and the organic phase outlet of the oil-water separation equipment are both connected with the organic solvent inlet of the organic solvent recovery equipment.
The hydrolysis reaction unit is used for providing a place for the diazo liquid to have hydrolysis reaction and is provided with a diazo liquid inlet, an organic solvent inlet, a sulfuric acid inlet and a hydrolysate outlet.
As a preferred technical solution of the present disclosure, the reactor used in the hydrolysis reaction unit includes any one of a microchannel reactor, a dynamic tubular reactor, a tubular static mixing reactor, or a tank reactor, or a combination of at least two of them. The microchannel reactor is provided with a reaction channel and a heat exchange channel, the characteristic dimension of the reaction channel is 1-15 mm, and the effective liquid holdup is 1-20L; the tubular static mixing reactor adopts jacket heat exchange, a mixing element with a turbulent flow effect is arranged in the reaction cavity, and the kettle type reactor is a conventional stirring kettle capable of exchanging heat.
As a preferred technical solution of the present disclosure, the apparatus used by the batching unit includes:
the first batching kettle is used for preparing a mixed solution of 2-methyl-3-aminobenzoic acid-sulfuric acid solution;
and the second batching kettle is used for preparing the sodium nitrite solution.
The 2-methyl-3-hydroxybenzoic acid can be prepared by the following method by using the continuous production device provided by the disclosure:
(A) mixing 2-methyl-3-aminobenzoic acid and a sulfuric acid solution in a first batching kettle to obtain a first mixed solution;
(B) mixing sodium nitrite and water in a second batching kettle to obtain a second mixed solution;
(C) the first mixed solution and the second mixed solution respectively enter a diazotization reaction unit through different conveying units to carry out diazotization reaction, so as to obtain a diazotization reaction solution;
(D) and (3) allowing the diazo liquid flowing out of the diazotization reaction unit to enter a hydrolysis reaction unit, and performing hydrolysis reaction in the presence of a sulfuric acid solution and an organic solvent to obtain a hydrolysate containing 2-methyl-3-hydroxybenzoic acid.
As a preferred technical scheme of the present disclosure, the equipment used by the batching unit further comprises a third batching kettle for preparing the urea solution, and the third batching kettle is provided with a urea solution outlet connected with the urea solution inlet of the impurity removal reaction unit.
First batching cauldron, second batching cauldron and third batching cauldron all have feed inlet and discharge gate, can select for use conventional stirred tank.
As a preferred technical solution of the present disclosure, the apparatus used by the conveying unit includes:
the first feeding pump is connected with the first batching kettle and used for conveying the first mixed liquid; and the second feeding pump is connected with the second batching kettle and used for conveying second mixed liquid. The first feeding pump and the second feeding pump are provided with a feeding hole and a discharging hole, and a common diaphragm pump, a gear pump, a screw pump or other feeding pumps capable of conveying slurry or liquid materials can be selected for use so as to convey the materials.
As a preferred technical scheme of the present disclosure, the conveying unit further comprises a third feeding pump, and the third feeding pump is connected with the third batching kettle and the impurity removal reaction unit.
In the present disclosure, the connection between units or devices should be construed broadly unless otherwise explicitly stated or limited. For example, the connection may be direct pipe connection, or may be pipe connection connected to conventional conveying, metering, controlling, and temporary storage equipment such as pumping equipment, metering equipment, valve pipe fittings, and intermediate tanks, or may be fixed connection or detachable connection. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
As a specific embodiment of the present disclosure, the following operations are performed using the continuous production apparatus provided above:
(A) mixing 2-methyl-3-aminobenzoic acid and a sulfuric acid solution in a first batching kettle to obtain a first mixed solution;
(B) mixing sodium nitrite and water in a second batching kettle to obtain a second mixed solution;
(C) the first mixed solution passes through a first feeding pump, and the second mixed solution passes through a second feeding pump, and the first mixed solution and the second mixed solution are both conveyed to a diazotization reaction unit for diazotization reaction to obtain a diazotization reaction solution;
(D) carrying out impurity removal reaction on the urea solution in the third batching kettle and the obtained diazo reaction solution in an impurity removal reaction unit;
(E) the reaction solution after impurity removal enters a hydrolysis reaction unit, and hydrolysis reaction is carried out in the presence of a sulfuric acid solution and an organic solvent to obtain a hydrolysate containing 2-methyl-3-hydroxybenzoic acid;
(F) and (3) allowing the hydrolysate flowing out of the hydrolysis reaction unit to enter a separation unit, and performing phase splitting, extraction, concentration and drying to obtain the 2-methyl-3-hydroxybenzoic acid.
As a specific embodiment of the present disclosure, the continuous production apparatus is composed of a batching unit, a conveying unit, a diazotization reaction unit, an impurity removal reaction unit, a hydrolysis reaction unit and a separation unit which are connected in sequence.
The reactor used by the diazotization reaction unit comprises a dynamic tubular reactor and a static tubular reactor which are connected in series, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit comprises a kettle type reactor, and the reactor used by the hydrolysis reaction unit is the kettle type reactor;
as a specific embodiment of the present disclosure, the reactor used by the diazotization reaction unit includes a dynamic tubular reactor and a kettle reactor which are connected in series, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit includes a kettle reactor, and the reactor used by the hydrolysis reaction unit is a static tubular reactor;
as a specific embodiment of the present disclosure, the reactor used by the diazotization reaction unit includes a dynamic tubular reactor, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit includes a kettle-type reactor, and the reactor used by the hydrolysis reaction unit is a dynamic tubular reactor, a dynamic tubular reactor and a static tubular reactor which are sequentially connected in series, or a dynamic tubular reactor and a kettle-type reactor which are sequentially connected in series;
as a specific embodiment of the present disclosure, the reactor used by the diazotization reaction unit includes a dynamic tubular reactor, the reactor used by the impurity removal reaction unit includes a dynamic tubular reactor, and the reactor used by the hydrolysis reaction unit includes a microchannel reactor, a microchannel reactor and a dynamic tubular reactor which are sequentially connected in series, or a microchannel reactor and a kettle reactor which are sequentially connected in series.
As a specific embodiment of the present disclosure, the continuous production apparatus is composed of a batching unit, a conveying unit, a diazotization reaction unit, a hydrolysis reaction unit and a separation unit which are connected in sequence.
As a specific embodiment of the present disclosure, the reactor used in the diazotization reaction unit includes a dynamic tubular reactor and a kettle reactor connected in series, the dynamic tubular reactor is connected with the conveying unit, and the reactor used in the hydrolysis reaction unit is a kettle reactor or a dynamic tubular reactor.
As a specific embodiment of the present disclosure, raw material 2-methyl-3-aminobenzoic acid and sulfuric acid solution are prepared in a first compounding kettle to obtain a first mixed solution, sodium nitrite and water are prepared in a second compounding kettle to obtain a second mixed solution, the first mixed solution and the second mixed solution are respectively conveyed to a reaction device of a diazotization reaction unit through a first feeding pump and a second feeding pump of a conveying unit to perform a diazotization reaction to obtain a diazotization solution, the diazotization solution flows into a hydrolysis reaction unit through a pipeline or is pumped into the hydrolysis reaction unit through a pumping device, and the diazotization solution contacts with an organic solvent and a sulfuric acid solution which are simultaneously pumped or pumped in advance to perform a hydrolysis reaction, so that a hydrolysate containing high-purity 2-methyl-3-hydroxybenzoic acid flows out of the hydrolysis reaction unit.
As a specific implementation mode of the present disclosure, raw materials 2-methyl-3-aminobenzoic acid and sulfuric acid solution are prepared in a first compounding kettle to obtain a first mixed solution, sodium nitrite and water are prepared in a second compounding kettle to obtain a second mixed solution, the first mixed solution and the second mixed solution are respectively conveyed to equipment of a diazotization reaction unit through a first feeding pump and a second feeding pump of a conveying unit to carry out diazotization reaction to obtain a diazotization solution, the diazotization solution flows into equipment of an impurity removal reaction unit through a pipeline or is pumped into the equipment of the impurity removal reaction unit through a pumping device, residual sodium nitrite in a hydrolysate and urea solution pumped in at the same time or pumped in advance are subjected to impurity removal reaction, the diazotization solution after impurity removal is exhausted and then enters a hydrolysis reaction unit, and is contacted with an organic solvent and sulfuric acid pumped in at the same time or pumped in advance to carry out hydrolysis reaction, and an outflow hydrolysis reaction containing high-purity 2-methyl-3-hydroxybenzoic acid is obtained And (4) units.
As a specific implementation mode of the disclosure, raw materials 2-methyl-3-aminobenzoic acid and sulfuric acid are prepared in a first material mixing kettle to obtain a first mixed solution, sodium nitrite and water are prepared in a second material mixing kettle to obtain a second mixed solution, the first mixed solution and the second mixed solution are respectively conveyed to equipment of a diazotization reaction unit through a first feeding pump and a second feeding pump of a conveying unit to carry out diazotization reaction to obtain a diazotization solution, the diazotization solution flows out of the diazotization reaction unit and flows into the equipment of an impurity removal reaction unit through a pipeline or a pumping device, residual sodium nitrite in a hydrolysate reacts with a urea solution pumped or pumped in advance at the same time, the diazotization solution after impurity removal is exhausted and then enters a hydrolysis reaction unit to be contacted with an organic solvent and sulfuric acid pumped in advance at the same time to carry out hydrolysis reaction, obtaining hydrolysate containing high-purity 2-methyl-3-hydroxybenzoic acid, flowing out of the hydrolysis reaction unit, flowing into a pipeline or pumping into an oil-water separation device of the separation unit through a pumping device to separate an aqueous phase and an organic phase, leaving the aqueous phase from the oil-water separation device to enter an aqueous phase extraction device, directly entering an organic solvent recovery device through the pipeline from the organic phase flowing out of the aqueous phase extraction device and the organic phase flowing out of the oil-water separation device, or flowing into an intermediate storage tank and then pumping into an organic solvent recovery device, returning the recovered organic phase to the hydrolysis reaction unit, conveying the obtained crude product to a drying device, drying to obtain a dried product, and flowing/pumping the aqueous phase flowing out of the aqueous phase extraction device into a sulfuric acid recovery device to obtain sulfuric acid capable of being used for diazotization or hydrolysis reaction.
The continuous production device provided by the disclosure for preparing the 2-methyl-3-hydroxybenzoic acid can simplify the process, reduce the occurrence of side reactions and improve the purity and yield of the product.
Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:
(1) the reactor used by the diazotization reaction unit is limited, so that the raw material can be subjected to diazotization reaction while the mixed solution of 2-methyl-3-aminobenzoic acid and sulfuric acid and the sodium nitrite solution are rapidly mixed in the diazotization reaction stage, a pre-mixing device can be omitted, and the purity and yield of the product can be improved;
(2) the continuous reaction device can simplify the process, reduce the occurrence of side reactions, and improve the purity and yield of the product, the purity of the product directly obtained by the raw materials after diazotization and hydrolysis can reach 99.6%, the yield can reach 98%, and the utilization rate of the raw materials is greatly improved;
(3) by utilizing the continuous production device provided by the disclosure, the directly obtained product has higher purity, does not need further purification, and can be directly sold or used for the production of downstream products;
(4) the continuous production device of 2-methyl-3-hydroxybenzoic acid provided by the disclosure can be applied to industrial continuous production, simplifies the production flow, reduces the production cost, and is really feasible after industrial production application.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
FIG. 1 is a first schematic structural diagram of a continuous reaction apparatus used in an embodiment of the present disclosure;
FIG. 2 is a second schematic structural diagram of a continuous reaction apparatus used in an embodiment of the present disclosure;
wherein, 1-a dosing unit; 101-a first batching kettle; 102-a second batching kettle; 103-a third batching kettle; 2-diazotization reaction unit; 3-impurity removal reaction unit; 4-a hydrolysis reaction unit; 5-separation unit.
Detailed Description
In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that the embodiments and features of the embodiments of the present disclosure may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced in other ways than those described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.
Fig. 1 is a first schematic structural diagram of a continuous production apparatus used in an embodiment of the present disclosure.
The continuous production device comprises a batching unit 1, a conveying unit, a diazotization reaction unit 2, an impurity removal reaction unit 3, a hydrolysis reaction unit 4 and a separation unit 5 which are connected in sequence, wherein the batching unit is connected with the diazotization reaction unit through a connecting pipe;
the batching unit 1 comprises: first batching cauldron 101, second batching cauldron 102 and third batching cauldron 103 all have feed inlet and discharge gate, can select for use conventional stirred tank.
The conveying unit comprises a first feeding pump, a second feeding pump and a third feeding pump which are provided with a feeding port and a discharging port, and a common diaphragm pump, a gear pump, a screw pump or other feeding pumps capable of conveying slurry or liquid materials can be selected to convey the materials.
The diazotization reaction unit 2 is provided with a first mixed solution inlet, a second mixed solution inlet and a diazotization solution outlet, and the reactor used by the diazotization reaction unit 2 comprises one of a dynamic tubular reactor, a dynamic tubular reactor series static tubular reactor and a dynamic tubular reactor series kettle type reactor.
The impurity removal reaction unit 3 is provided with a diazo liquid inlet, a urea solution inlet and an impurity removed diazo liquid outlet, the diazo liquid inlet is connected with the diazo liquid outlet of the diazotization reaction unit 2, the impurity removed diazo liquid outlet is connected with the diazo liquid inlet of the hydrolysis reaction unit 4, a kettle type reactor or a dynamic tubular reactor can be selected, an exhaust port can be arranged in addition, or a discharge port of the impurity removal reaction unit 3 is connected with a gas-liquid separation device for discharging gas generated in the impurity removal process.
The hydrolysis reaction unit 4 is provided with a diazo liquid inlet, an organic solvent inlet, a sulfuric acid inlet and a hydrolysate outlet, and the used reactor comprises any one or the combination of at least two of a microchannel reactor, a dynamic tubular reactor, a tubular static mixing reactor or a kettle type reactor.
The equipment used by the separation unit 5 comprises an oil-water separator, water phase extraction equipment and organic solvent recovery equipment.
The oil-water separation equipment is provided with a hydrolysate inlet, an organic phase outlet and a water phase outlet, and can select a conventional oil-water separator on the market; the water phase extraction equipment is provided with a water phase inlet, an organic solvent inlet, an extracted water phase outlet and an extracted organic phase outlet, and can select an extraction tower or a centrifugal extractor or other equipment capable of realizing the extraction function; the organic solvent recovery device is provided with an organic phase inlet, an organic solvent outlet and a product outlet, and can be selected from evaporation concentration devices.
The equipment used by the separation unit also comprises sulfuric acid recovery equipment and drying equipment, wherein the sulfuric acid recovery equipment can select a distillation still or a rectifying tower, and the drying equipment can select a roller dryer, a rotary drum dryer, a film dryer or other equipment capable of realizing product drying.
The hydrolysate outlet of the hydrolysis reaction unit is communicated with the hydrolysate inlet of the oil-water separation equipment, the water phase outlet of the oil-water separation equipment is connected with the water phase inlet of the water phase extraction equipment, and the organic phase outlet of the water phase extraction equipment and the organic phase outlet of the oil-water separation equipment are both connected with the organic solvent inlet of the organic solvent recovery equipment.
In carrying out the preparation of 2-methyl-3-hydroxybenzoic acid:
(1) in the batching unit 1, 2-methyl-3-aminobenzoic acid and sulfuric acid solution are added into a first batching kettle 101 and mixed to obtain a mixed solution (first mixed solution) of 2-methyl-3-aminobenzoic acid and sulfuric acid solution, sodium nitrite and water are added into a second batching kettle 102 and mixed to obtain sodium nitrite solution (second mixed solution), and meanwhile, a urea solution is prepared in a third batching kettle 103;
(2) the first mixed solution and the second mixed solution are respectively conveyed to a diazotization reaction unit 2 through a first feeding pump and a second feeding pump of a conveying unit according to a certain proportion to carry out diazotization reaction, so as to obtain a diazotization solution;
(3) the diazo liquid flowing out from the diazotization reaction unit 2 enters an impurity removal reaction unit 3, and is subjected to impurity removal reaction with urea solution, and enters a hydrolysis reaction unit 4 after being detected by starch potassium iodide test paper and not changing blue;
(4) in a hydrolysis reaction unit 4, carrying out hydrolysis reaction in the presence of sulfuric acid and an organic solvent to obtain a hydrolysate containing 2-methyl-3-hydroxybenzoic acid;
(5) the hydrolysate flowing out of the hydrolysis reaction unit 4 enters a separation unit 5, an aqueous phase and an organic phase are separated in an oil-water separator, and the aqueous phase enters extraction equipment to extract the residual organic phase; and combining the organic phases, concentrating the organic phases and the like to obtain 2-methyl-3-hydroxybenzoic acid, returning the recovered organic solvent to the hydrolysis reaction unit 4 for subsequent hydrolysis reaction, extracting the residual organic phase from the residual aqueous phase after extraction, and then removing organic matters, concentrating and desalting to obtain sulfuric acid which can be used for diazotization or hydrolysis reaction, wherein the sulfuric acid can be returned to the first batching kettle 101 for diazotization reaction or can enter the hydrolysis reaction unit 4 for hydrolysis reaction.
Fig. 2 is a schematic structural diagram of a continuous production apparatus used in the embodiment of the present disclosure.
The continuous production device comprises a batching unit 1, a conveying unit, a diazotization reaction unit 2, a hydrolysis reaction unit 4 and a separation unit 5 which are connected in sequence.
In carrying out the preparation of 2-methyl-3-hydroxybenzoic acid:
(1) in the batching unit 1, adding 2-methyl-3-aminobenzoic acid and a sulfuric acid solution into a first batching kettle 101 for mixing to obtain a mixed solution (a first mixed solution) of 2-methyl-3-aminobenzoic acid and the sulfuric acid solution, adding sodium nitrite and water into a second batching kettle 102 for mixing to obtain a sodium nitrite solution (a second mixed solution);
(2) the first mixed solution and the second mixed solution are respectively conveyed to a diazotization reaction unit 2 through a first feeding pump and a second feeding pump of a conveying unit according to a certain proportion to carry out diazotization reaction, so as to obtain a diazotization solution;
(3) the diazo liquid flowing out from the diazotization reaction unit 2 enters a hydrolysis reaction unit 4, and hydrolysis reaction is carried out in the hydrolysis reaction unit 4 in the presence of sulfuric acid and an organic solvent to obtain a hydrolysate containing 2-methyl-3-hydroxybenzoic acid;
(4) the hydrolysate flowing out of the hydrolysis reaction unit 4 enters a separation unit 5, an aqueous phase and an organic phase are separated in an oil-water separator, and the aqueous phase enters extraction equipment to extract the residual organic phase; and combining the organic phases, concentrating the organic phases and the like to obtain 2-methyl-3-hydroxybenzoic acid, returning the recovered organic solvent to the hydrolysis reaction unit 4 for subsequent hydrolysis reaction, extracting the residual organic phase from the residual aqueous phase after extraction, and then removing organic matters, concentrating and desalting to obtain sulfuric acid which can be used for diazotization or hydrolysis reaction, wherein the sulfuric acid can be returned to the first batching kettle 101 for diazotization reaction or can enter the hydrolysis reaction unit 4 for hydrolysis reaction.
Example 1
This example provides a method for continuously producing 2-methyl-3-hydroxybenzoic acid by using the continuous production apparatus shown in FIG. 1.
(1) Adding a raw material of 2-methyl-3-aminobenzoic acid and 18% sulfuric acid in a molar ratio of 1:2 into a first batching kettle, mixing to obtain a first mixed solution, adding sodium nitrite and water into a second batching kettle, and mixing to obtain a 25% sodium nitrite solution, namely a second mixed solution;
(2) the first mixed solution and the second mixed solution are respectively conveyed to a dynamic tubular reactor with a liquid holdup of 20L in a diazotization reaction unit through a first feeding pump and a second feeding pump of a conveying unit at flow rates of 5.63kg/min and 1.32kg/min, the reaction is carried out for 2.9min at the temperature of 10 ℃, then the reaction is transferred to a wound tubular reactor with a liquid holdup of 50L, the heat preservation and the stirring are continuously carried out for 7.1min at the temperature of 10 ℃, and then diazotization solution is obtained, wherein the molar dosage of sodium nitrite is 1.05 times of that of the raw material;
(3) allowing the diazonium solution to flow out from an outlet of the winding pipe type reactor, allowing the diazonium solution and 35% urea solution with the flow rate of 0.05kg/min to enter an impurity removal kettle, reacting at 20 ℃ until the diazonium solution is detected by potassium iodide starch test paper and does not turn blue, and discharging the diazonium solution from an overflow port;
(4) pumping the diazo liquid after impurity removal into a microchannel reactor and a dynamic tubular reactor which are sequentially connected in series in a hydrolysis reaction unit through a feed pump connected on a pipeline, and mixing and reacting with sulfuric acid with the mass concentration of 45% and methyl isobutyl ketone which are pumped simultaneously for 5min at the temperature of 90 ℃, wherein the molar consumption of the sulfuric acid is 2.5 times of that of the raw material, and the mass of the methyl isobutyl ketone is 8 times of that of the raw material;
(5) and (3) allowing hydrolysate obtained after reaction to flow out of the dynamic tubular reactor and enter a separation unit, separating an aqueous phase and an organic phase in an oil-water separator, allowing the aqueous phase to enter aqueous phase extraction equipment to extract a residual organic phase, allowing two organic phases to enter organic solvent recovery equipment to recover methyl isobutyl ketone in the organic phase, and drying the solid by a dryer to obtain the product 2-methyl-3-hydroxybenzoic acid.
Example 2
This example provides a method for continuously producing 2-methyl-3-hydroxybenzoic acid by using the continuous production apparatus shown in FIG. 2.
(1) Adding a raw material of 2-methyl-3-aminobenzoic acid and sulfuric acid with the mass concentration of 30% into a first batching kettle according to the molar ratio of 1:3, mixing to obtain a first mixed solution, adding sodium nitrite and water into a second batching kettle, and mixing to obtain a 40% sodium nitrite solution, namely a second mixed solution;
(2) the first mixed solution and the second mixed solution are respectively conveyed to a dynamic tubular reactor with a liquid holdup of 5L in a diazotization reaction unit through a first feeding pump and a second feeding pump of a conveying unit at flow rates of 6.03kg/min and 0.92kg/min, the reaction is carried out for 0.7min at the temperature of 40 ℃, then the reaction is transferred to a tubular static mixing reactor with a liquid holdup of 2L, the heat preservation and the stirring are continuously carried out for 0.3min at the temperature of 30 ℃, and then diazotization solution is obtained, wherein the molar amount of sodium nitrite is the same as that of the raw material;
(3) pumping the diazo liquid into a microchannel reactor of a hydrolysis reaction unit through a feed pump connected to a pipeline, and mixing and reacting the diazo liquid with 60% sulfuric acid and xylene which are pumped simultaneously at 130 ℃ for 0.5min, wherein the molar consumption of the sulfuric acid is 5 times of that of the raw material, and the mass of the xylene is 8 times of that of the raw material;
(4) and enabling the hydrolysate obtained after the reaction to flow out of the automatic state tubular reactor and enter a separation unit, separating an aqueous phase and an organic phase in an oil-water separator, enabling the aqueous phase to enter aqueous phase extraction equipment to extract a residual organic phase, enabling the two organic phases to enter organic solvent recovery equipment to recover xylene in the organic phase, and drying the solid through a dryer to obtain the product 2-methyl-3-hydroxybenzoic acid.
Comparative example 1
This comparative example provides a method of preparing 2-methyl-3-hydroxybenzoic acid.
(1) Adding 583.48kg of 2-methyl-3-aminobenzoic acid into a reaction kettle, conveying concentrated sulfuric acid to a high-level tank through a tank area material pump through a pipeline, then adding the concentrated sulfuric acid into the reaction kettle through a pipeline, adding water through a tap water pipeline, recycling sulfuric acid, adding the recycled sulfuric acid into the reaction kettle through a pump through a pipeline, starting stirring, heating to 65-70 ℃ to obtain a clarified solution, starting frozen brine, cooling to about 0 ℃, starting to add 319.4kg of sodium nitrite aqueous solution through a flowmeter, and keeping the temperature in the reaction kettle to be lower than 5 ℃ in the process;
(2) after the sodium nitrite is added, stirring is continued for 1 hour, then urea with a process amount is added (excessive nitroso is removed), then the reaction liquid is transferred to a hydrolysis reaction kettle, concentrated sulfuric acid aqueous solution with a specified amount and concentration is added into the hydrolysis reaction kettle through a flow meter, stirring is started, the temperature is slowly heated to 85-90 ℃, the temperature is kept for 2 hours, after the central control detection is qualified, circulating water is started to be cooled to 25-35 ℃, ethyl acetate is used for extraction, the water layer is reused as recovered sulfuric acid after secondary concentration and desalination, organic layers are combined, the solvent is decompressed, concentrated, crystallized and filtered, and reused in the next batch to obtain a solid wet product of 3-hydroxy-2-methylbenzoic acid, and drying is carried out to obtain the 3-hydroxy-2-methylbenzoic acid.
And (4) performance testing: yield and product purity
(1) The product and the product purity detection method comprise the following steps:
weighing 50.0mg of 2-methyl-3-hydroxybenzoic acid sample in a 50mL volumetric flask, adding methanol to completely dissolve the sample and dilute to a scale mark, shaking up, filtering by using a filter to obtain a test solution, using a micro-syringe to take about 5 mu L of sample and inject the sample into a liquid chromatogram, and repeatedly measuring each sample for two times;
the specification of the chromatographic column is phi 4.6 x 150mm and 5 μm, the material of the column is C18, the temperature of the column is 35 ℃, the mobile phase is methanol and water (0.1 percent phosphoric acid) is 40:60, the flow rate is 1.0mL/min, and the detection wavelength is 212 nm.
(2) The product yield and the effective utilization rate of the raw materials are calculated by the following formula:
the product yield (mass of dried product/mass of theoretical product) × 100%;
the effective utilization rate of the raw material is (product purity x product yield) x 100%;
the results of the tests on examples 1-2 and comparative example 1 are shown in Table 1:
TABLE 1
Note: yield: samples obtained from 10min of continuous feed were collected and then calculated.
According to the embodiment and the performance test, the continuous production device provided by the disclosure is used for continuous production, the directly obtained product has high purity, the product yield is high, and the raw material utilization rate is high, namely the preparation method provided by the disclosure can reduce the production cost, improve the production efficiency, and perform industrial continuous production.
As can be seen from comparison between examples 1-2 and comparative example 1, the continuous production device provided by the present disclosure can perform industrial continuous production, and has high production efficiency and high product purity.
It is noted that, herein, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description is only for the purpose of describing particular embodiments of the present disclosure, so as to enable those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. The continuous production device of the 2-methyl-3-hydroxybenzoic acid is characterized by comprising a batching unit, a conveying unit, a diazotization reaction unit and a hydrolysis reaction unit which are connected in sequence;
wherein the reactor used by the diazotization reaction unit comprises one of a dynamic tubular reactor, a dynamic tubular reactor series static tubular reactor and a dynamic tubular reactor series kettle type reactor.
2. The continuous production apparatus according to claim 1, further comprising an impurity removal reaction unit located between the diazotization reaction unit and the hydrolysis reaction unit, wherein the diazotization reaction unit and the hydrolysis reaction unit are connected through the impurity removal reaction unit;
and/or, the continuous production device further comprises a separation unit connected with the hydrolysis reaction unit.
3. The continuous production device according to claim 2, wherein the reactor used by the impurity removal reaction unit comprises a tank reactor or a dynamic tube reactor.
4. The continuous production apparatus according to claim 2, wherein the separation unit uses equipment including an oil-water separator, an aqueous phase extraction equipment, an organic solvent recovery equipment, a sulfuric acid recovery equipment, and a drying equipment.
5. The continuous production apparatus according to claim 1, wherein the reactor used in the hydrolysis reaction unit comprises any one of or a combination of at least two of a microchannel reactor, a dynamic tube reactor, a tubular static mixing reactor or a tank reactor.
6. The continuous production device according to claim 1, characterized in that the equipment used by the batching unit comprises:
the first batching kettle is used for preparing a mixed solution of 2-methyl-3-aminobenzoic acid-sulfuric acid solution;
the second batching kettle is used for preparing the sodium nitrite solution;
and/or the equipment used by the conveying unit comprises:
the first feeding pump is connected with the first batching kettle;
the second feeding pump is connected with the second batching kettle;
the first feeding pump and the second feeding pump are respectively and independently selected from diaphragm pumps, gear pumps or screw pumps.
7. The continuous production apparatus according to any one of claims 1 to 6, wherein the continuous production apparatus is composed of a batching unit, a conveying unit, a diazotization reaction unit, an impurity removal reaction unit, a hydrolysis reaction unit and a separation unit, which are connected in sequence.
8. The continuous production device according to claim 7, wherein the reactor used by the diazotization reaction unit comprises a dynamic tubular reactor and a static tubular reactor which are connected in series, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit comprises a tank reactor, and the reactor used by the hydrolysis reaction unit is a tank reactor;
or the reactor used by the diazotization reaction unit comprises a dynamic tubular reactor and a kettle type reactor which are connected in series, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit comprises a kettle type reactor, and the reactor used by the hydrolysis reaction unit is a static tubular reactor;
or the reactor used by the diazotization reaction unit comprises a dynamic tubular reactor, the dynamic tubular reactor is connected with the conveying unit, the reactor used by the impurity removal reaction unit comprises a kettle reactor, and the reactor used by the hydrolysis reaction unit comprises a dynamic tubular reactor, a dynamic tubular reactor and a static tubular reactor which are sequentially connected in series or a dynamic tubular reactor and a kettle reactor which are sequentially connected in series;
or, the reactor that the diazotization reaction unit used includes dynamic tubular reactor, the reactor that edulcoration reaction unit used includes dynamic tubular reactor, the reactor that the hydrolysis reaction unit used is microchannel reactor, the microchannel reactor and the dynamic tubular reactor that establish ties in proper order or microchannel reactor and the kettle type reactor that establish ties in proper order.
9. The continuous production apparatus according to any one of claims 1 to 6, characterized in that the continuous production apparatus is composed of a batching unit, a conveying unit, a diazotization reaction unit, a hydrolysis reaction unit and a separation unit, which are connected in this order.
10. The continuous production device according to claim 9, wherein the reactor used by the diazotization reaction unit comprises a dynamic tubular reactor and a tank reactor which are connected in series, the dynamic tubular reactor is connected with the conveying unit, and the reactor used by the hydrolysis reaction unit is the tank reactor or the dynamic tubular reactor.
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