CN109663546B - Special reactor for synthesizing acetanilide - Google Patents
Special reactor for synthesizing acetanilide Download PDFInfo
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- CN109663546B CN109663546B CN201910128783.4A CN201910128783A CN109663546B CN 109663546 B CN109663546 B CN 109663546B CN 201910128783 A CN201910128783 A CN 201910128783A CN 109663546 B CN109663546 B CN 109663546B
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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
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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Abstract
The invention discloses a reactor special for synthesizing acetanilide, which comprises a reactor body, wherein the reactor body consists of a reactor top, a reactor bottom and a reactor side wall, and is characterized in that a gas outlet is formed in the top of the reactor body; the bottom of the reactor body is provided with a liquid outlet; a packing area is arranged at the lower part of the reactor body; two hollow feeding plates are arranged at the middle upper part of the reactor body, and a space for material flowing is reserved between the hollow feeding plates and the outer wall of the reactor.
Description
Technical Field
The invention belongs to the technical field of chemical equipment, and particularly relates to a special reactor for synthesizing acetanilide.
Background
Acetanilide, also known as N-phenyl (yl) acetamide, white lustrous flaky crystals or white crystalline powder, is a raw material of sulfonamides and can be used as an analgesic, antipyretic and preservative. Used for manufacturing dye intermediates of paranitroacetanilide, paranitroaniline and p-phenylenediamine. It is used in large quantities for manufacturing p-acetamido-benzenesulfonyl chloride in world war II. Acetanilides are also used in the production of thioacetamides. Can be used as rubber vulcanization accelerator, stabilizer for fiber grease coating, stabilizer for hydrogen peroxide, and synthetic camphor. It is also used as a medium for preparing penicillin G. The analgesic and antipyretic of the previous generation has been replaced by a new generation of acetyl drugs, such as acetaminophen and acetaminophen, due to its low toxicity.
In the prior art, acetanilide is generally prepared by the following method: obtained by acetylating aniline with acetic acid. Aniline and glacial acetic acid (100% excess) were placed in a jacketed glass lined reactor and refluxed for 6-14h until free aniline was absent. If dilute acetic acid is used, the reaction temperature is 150-160 ℃, the mixture is filtered when the reaction is finished, the residue is removed, and the filtrate is cooled, crystallized, centrifugally filtered, washed with water and dried to obtain the product. Alternatively, acetic anhydride may be used as the acylating agent and the reaction may be carried out in benzene solution with an acetic anhydride excess of 150%.
Typically, four reaction tanks are arranged in a ladder configuration, with the top one being equipped with a fractionation column. Aniline is continuously added from the top of the fractionating column, a mixture of recovered acetic acid and aniline is continuously added from the second reaction tank, and acetic acid is continuously added from the third reaction tank. Controlling different reaction temperatures (the third is 160-. The equipment used in the reaction process is various.
The present inventors have also conducted corresponding studies, and for example, chinese patent publication No. CN106518705A discloses the synthesis of acetoacetanilide. Relates to the synthesis of acetoacetanilide, which comprises the following steps: ethyl acetoacetate 5.31mmol, aniline 5.31mmol, and 4-dimethylaminopyridine 0.531mmol are weighed into a 25mL single-neck flask, then 10-30mL toluene is added, heating, stirring, refluxing are carried out for 20-36h, after the disappearance of the raw materials is monitored by thin layer chromatography (petroleum ether: ethyl acetate 4: 1 Rf: 0.37), the reaction is ended, water is added, the reaction solution is transferred into a separating funnel, ethyl acetate (20 mL. times.3) is extracted, the obtained organic phase is collected, then the organic phase is washed by saturated sodium chloride, dried by anhydrous MgSO4, the solid is removed by filtration, the filtered filtrate is collected and is rotary evaporated, and the target compound acetoacetanilide is isolated by taking petroleum ether: ethyl acetate 10: 1 as an eluent. For another example, chinese patent publication No. CN202945186U discloses a reaction apparatus for preparing isobutyrylacetanilide. Including reation kettle, rectifying column, receiving condenser and receiving tank, the top at reation kettle is fixed to the rectifying column, the rectifying column passes through the pipeline and receives the condenser intercommunication, receive condenser and receiving tank intercommunication, be provided with cooling water inlet tube I and cooling water outlet pipe I on the receiving condenser, its characterized in that: still be provided with reflux condenser between rectifying column and receiving condenser, this reflux condenser fixes at the top of rectifying column, the last cooling water inlet pipe II and the cooling water outlet pipe II of being provided with of reflux condenser.
However, the reaction process or reactor in these studies was not for acetanilide. It was not known whether or not the process was suitable for the synthesis of acetanilide. To date, no dedicated reactor is available in the prior art for the directional synthesis of acetanilide.
Disclosure of Invention
The purpose of the invention is as follows: for the acetanilide synthesis reaction, if the reaction temperature is too high and is close to the distillation temperature of the glacial acetic acid, the reaction is not completely carried out, and the glacial acetic acid is continuously distilled off, so that the reaction is not facilitated. Even more disadvantageously, bumping may also occur. Therefore, it is desirable to lower the reaction temperature, but too low a temperature is disadvantageous in advancing the reaction in the forward direction, and the conversion rate and the yield are lowered. A common suitable reaction temperature is between 90 and 100 ℃. Therefore, it is difficult to maintain the conversion and selectivity even when the reaction temperature is lowered. This requires an increase in the mass transfer efficiency of the reactants to allow sufficient contact of the reactants. Therefore, a special reactor for the synthesis reaction of the acetanilide is designed. The reaction can be carried out at 60-70 ℃.
The technical scheme is as follows: the reactor special for synthesizing the acetanilide comprises a reactor body 1, wherein the reactor body 1 consists of the top, the bottom and a side wall of the reactor, and is characterized in that a gas outlet 4 is formed in the top of the reactor body 1; the bottom of the reactor body 1 is provided with a liquid outlet 5; the lower part of the reactor body 1 is provided with a filler zone 6; the middle upper part of the reactor body 1 is provided with two hollow feeding plates 2, and a space for material to flow is reserved between the hollow feeding plates 2 and the outer wall of the reactor;
the hollow feeding plate 2 is vertically arranged, the upper part of the hollow feeding plate is provided with an air inlet 21, the lower part of the hollow feeding plate is provided with a liquid inlet 22, the interior of the hollow feeding plate 2 is hollow, the interior of the hollow feeding plate is a hollow cavity, and gas and liquid can be mixed; two sides of the middle part of the hollow feeding plate 2, wherein one side is a non-porous flat plate, and the other side is provided with a plurality of small holes for atomizing and spraying gas and liquid after mixing.
Specifically, the two hollow feeding plates are symmetrically arranged; and the small holes of the two hollow feeding plates are arranged on different sides, so that the mixture atomized and ejected from the small holes can flow clockwise. For the purposes of the present invention, the distribution of the orifices is more specific, the smaller the number of said orifices, the closer they are to the center of the reactor, the greater the number of orifices, the closer they are to the outer wall of the reactor. More preferably, the orifices are divided into 5 rows, the number of the first row near the middle of the reactor is 2, the number of the first row is increased in turn, and the number of the sixth row is 7. Through the arrangement, good aerial fog vortex can be realized in the reactor, the mass transfer and heat transfer of reactants are promoted, and the reaction efficiency is improved.
Furthermore, we have studied the distribution of the small holes, if the distance between the small holes is too large, the outlet temperature distribution coefficient (or the outlet hot spot distribution coefficient OTDF) is too large (especially in the high power state), if the distance between the small holes is too small, that is, the number of the small holes is too large, and under the same size of the small holes and the same air flow condition, the air pressure difference is reduced, so that the fogging effect is poor and the stability is poor. Therefore, the most suitable distribution range is designed, namely the diameter of the small holes is less than 5mm, and the hole-to-hole distance is 5-15 cm.
The reactor is also provided with a filler area, and the filler of the filler area is activated carbon. Further research shows that the effect is better if the active carbon is loaded with zinc, and the loading amount of the zinc is preferably 3 percent for the reaction.
The excessive amount of glacial acetic acid used for the reaction often leads to acid accumulation in the reactor, which deactivates the catalyst and is not favorable for the reaction. Therefore, the material of the hollow feeding plate is very high in requirement, and the material is made of corrosion-resistant special steel. Specifically, the corrosion-resistant special steel comprises the following components: 0.01-0.03% of carbon, 16% of chromium, 7% of nickel, 0.1% of copper, 0.4% of tungsten, 0.3-0.8% of niobium and the balance of iron.
The invention also provides a preparation method of the corrosion-resistant special steel, which comprises the following steps: the preparation method comprises the following steps of proportioning raw materials, forging, carrying out heat treatment, placing the raw materials in a container filled with water vapor, keeping the raw materials at the temperature of 120-125 ℃ and the pressure of 1.2-1.5 MPa for 2-4 hours, replacing the water vapor with air, and keeping the raw materials at the temperature of 150-155 ℃ and the pressure of 1.2-1.5 MPa for 2-4 hours to obtain the product.
Specifically, the heat treatment is: heating the steel to 860-880 ℃, preserving heat for 1-2 hours, discharging the steel after isothermal annealing and general annealing, preheating twice, raising the temperature to 1220-1280, keeping the temperature for 0.5-1 hour, quenching, immediately tempering after quenching, and tempering for three times. The obtained material completely meets the requirements of the professional reactor of the invention and can be used in the environment of glacial acetic acid for a long time.
Has the beneficial effects that: compared with the conventional reactor, the invention has incomparable heat and mass transfer effects, and firstly, the two raw materials are effectively atomized, and secondly, vortex is ingeniously formed in the reactor, so that the reaction can be carried out at 60-70 ℃, and the yield of the product is not lower than 80%. Due to the cross flow contact of the vapor and the liquid, the vapor phase resistance is greatly reduced, the flooding gas velocity is improved, and the power equipment and the operation cost are reduced. In addition, in order to adapt to the special requirements of the reaction, the preparation method of the corrosion-resistant special steel is provided, the obtained material completely meets the requirements of the special reactor of the invention, and the material can be used in the environment of glacial acetic acid for a long time.
Drawings
FIG. 1 is a schematic view of a reactor according to the present invention
FIG. 2 is a schematic view of the flow of materials in the reaction of the reactor according to the present invention
FIG. 1-reactor body; 2-a hollow feed plate; 3-small holes; 4-gas exhaust port; 5-a liquid discharge port; 6-a packing zone; 21-an air inlet; 22-liquid inlet.
The specific implementation mode is as follows:
as shown in figure 1, the invention comprises a reactor body 1, wherein the reactor body 1 consists of a reactor top, a reactor bottom and a reactor side wall, and the top of the reactor body 1 is provided with a gas outlet 4; the bottom of the reactor body 1 is provided with a liquid outlet 5; a packing area is arranged at the lower part of the reactor body 1; the middle upper part of the reactor body 1 is provided with two hollow feeding plates 2, and a space for material to flow is reserved between the hollow feeding plates 2 and the outer wall of the reactor; the hollow feeding plate 2 is vertically arranged, the upper part of the hollow feeding plate is provided with an air inlet 21, the lower part of the hollow feeding plate is provided with a liquid inlet 22, and the hollow feeding plate 2 is internally provided with a hollow cavity for mixing air and liquid; two sides of the middle part of the hollow feeding plate 2, wherein one side is a non-porous flat plate, and the other side is provided with a plurality of small holes for atomizing and spraying gas and liquid after mixing.
The two hollow feeding plates are symmetrically arranged; and the small holes of the two hollow feeding plates are arranged on different sides, so that the mixture atomized and sprayed from the small holes can flow clockwise. The small holes are less close to the center of the reactor and more close to the outer wall of the reactor. The small holes are divided into 5 rows, the number of the first row close to the middle of the reactor is 2, each row is increased in turn, and the number of the sixth row is 7. The diameter of the small holes is smaller than 5mm, and the hole distance between the holes is 5-15 cm.
The filler filled in the filler area is activated carbon loaded with zinc.
In the reaction process, nitrogen is introduced from an air inlet 21, and aniline is introduced from a liquid inlet 22; the nitrogen and aniline are mixed in the cavity of the hollow feed plate 2 and the mixed mixture is atomized and sprayed from a small hole on one side. Correspondingly, the nitrogen and the glacial acetic acid are mixed by another hollow feeding plate in the reactor and are atomized and sprayed out. The aperture of two cavity feed plates locates different one sides, and whole can be effectual like this make spray and the mixture that goes out form effectual vortex in the reactor, reach best mass and heat transfer effect for the reaction can be effectual going on under microthermal environment
After 10 hours of reaction, the product was received and was found to have an acetanilide yield of 82%. Compared with the conventional reaction device, the method can ensure that the reaction is carried out at 60-70 ℃, greatly reduces the energy consumption, and avoids the adverse effect of high temperature on the method on the premise of meeting the same yield.
The above-mentioned embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Claims (4)
1. A reactor special for synthesizing acetanilide comprises a reactor body (1), wherein the reactor body (1) consists of the top, the bottom and a side wall of the reactor, and is characterized in that a gas outlet (4) is formed in the top of the reactor body (1); the bottom of the reactor body (1) is provided with a liquid outlet (5); a packing area (6) is arranged at the lower part of the reactor body (1); the middle upper part of the reactor body (1) is provided with two hollow feeding plates (2), and a space for material to flow is reserved between the hollow feeding plates (2) and the outer wall of the reactor;
the hollow feeding plate (2) is vertically arranged, the upper part of the hollow feeding plate is provided with an air inlet (21), the lower part of the hollow feeding plate is provided with a liquid inlet (22), and the hollow feeding plate (2) is internally provided with a hollow cavity for mixing gas and liquid; two sides of the middle part of the hollow feeding plate (2), wherein one side is a non-porous flat plate, and the other side is provided with a plurality of small holes (3) which can be used for atomizing and spraying gas and liquid after mixing;
the two hollow feeding plates are symmetrically arranged; the small holes of the two hollow feeding plates are arranged on different sides, so that the mixture atomized and ejected from the small holes can flow clockwise;
the smaller the pores are, the closer the pores are to the center of the reactor, the fewer the pores are, and the closer the pores are to the outer wall of the reactor, the more the pores are;
the small holes are divided into 5 rows, the number of the first row close to the middle of the reactor is 2, each row is increased in turn, and the number of the sixth row is 7.
2. A special reactor as claimed in claim 1, wherein the diameter of said small holes is less than 5mm and the hole-to-hole distance is 5-15 cm.
3. A specialized reactor as defined in claim 1 wherein said packing material in said packing region is activated carbon.
4. A specialized reactor as defined in claim 3 wherein said activated carbon is zinc loaded activated carbon.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910128783.4A CN109663546B (en) | 2019-02-21 | 2019-02-21 | Special reactor for synthesizing acetanilide |
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| CN201910128783.4A CN109663546B (en) | 2019-02-21 | 2019-02-21 | Special reactor for synthesizing acetanilide |
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| CN109663546B true CN109663546B (en) | 2022-09-06 |
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