CN115228417A - Synthesis device and synthesis method of m-nitrobenzotrifluoride - Google Patents

Abstract

The invention discloses a m-nitrobenzotrifluoride synthesis device and a synthesis method, which belong to the field of nitration reaction and comprise the following steps: the feeding end of the first-stage reactor is provided with a feeding mechanism, the outlet end of the first-stage reactor is provided with a second-stage reactor, and a stirring mechanism is arranged inside the first-stage reactor; the main shaft is rotatably arranged at the other side of the secondary reactor, is mechanically sealed and is connected with the motor, and the main shaft extends into the secondary reactor; the mixing disc consists of a main disc and an auxiliary disc, is arranged in the secondary reactor, is matched with the main shaft, and is fixedly arranged in the cavity of the secondary reactor and separates the cavity; the heat exchanger is arranged at the outlet end of the secondary reactor, and can mix the mixtures with different depths in the inner wall of the reactor together, reduce the mixture with the layering phenomenon on the inner wall of the reactor, so that the mixture at the inner wall of the reactor can be fully reacted.

Description

Synthesis device and synthesis method of m-nitrobenzotrifluoride

Technical Field

The invention relates to the field of nitration reaction, and more particularly relates to a m-nitrobenzotrifluoride synthesis device and a synthesis method.

Background

The synthesis of m-nitrobenzotrifluoride is to prepare mixed nitro compound (other is about 8 percent of o-nitrobenzotrifluoride and about 1.5 percent of p-nitrobenzotrifluoride) taking m-nitrobenzotrifluoride as main components by nitration reaction of mixed acid prepared from sulfuric acid and nitric acid and benzotrifluoride, and the production of the mixed nitro compound takes a common single-kettle intermittent reaction or multi-kettle series continuous reaction, and compared with the multi-kettle series continuous reaction, the intermittent kettle type continuous reaction has the advantages of complex operation control, low unit equipment efficiency, more sulfuric acid and nitric acid consumption and is a process which is gradually eliminated;

through patent retrieval, chinese patent with publication number CN113244871A discloses an environment-friendly nitration reactor, which comprises a reactor, a driving motor, a heat exchange jacket, a water inlet pipe, a water outlet pipe, a feed inlet, a discharge outlet, a reciprocating screw rod, a stirring rod, a helical blade, a waste gas treatment cavity and a nitration reaction cavity, wherein although the driving motor is matched with the rotating rod to conveniently drive a cross column to rotate in the nitration reaction cavity, the cross column is matched with a first self-rotation assembly in the rotating process to enable the reciprocating screw rod to rotate automatically, so that a screw rod sliding block can reciprocate along a through groove, the screw rod sliding block drives the stirring rod to move synchronously and horizontally, a bearing seat is matched with a second self-rotation assembly to enable the stirring rod to rotate automatically in the horizontal movement process, the helical blade is matched to conveniently stir materials, and the driving motor can drive the whole partition plate to do annular movement, so that the materials in the nitration reaction cavity can be stirred in all directions conveniently, and dead angles of stirring are avoided, thereby effectively improving the effect of nitration reaction;

(1) But the problems that the existing environment-friendly nitration reactor can rotate automatically in the process of stirring the mixture by the stirring rod in the horizontal movement process to drive the helical blades to rotate and stir the mixture in the reactor, the helical blades are inconvenient to slide along the inner wall of the reactor, and the mixture on the inner wall of the reactor can only be driven by the stirring rod to move unidirectionally in the horizontal plane, so that the mixtures at different depths in the inner wall of the reactor are difficult to mix together, the mixture is easy to have a layering phenomenon, and the mixture at the inner wall of the reactor is not reacted sufficiently are not solved, and therefore, the m-nitrobenzotrifluoride synthesis device and the synthesis method are provided;

(2) The reaction kettle has high local temperature, prolonged reaction time and high content of required mixed acid due to insufficient stirring in the production process, when the m-nitrobenzotrifluoride is produced, the reaction temperature is high, the reaction time is long, side reactions such as decomposition or polymerization of materials are easy to occur, F-contained in the reaction acid is increased (about more than 2000 PPm), the higher the F-concentration is, the higher the requirement on corrosion resistance of equipment is when sulfuric acid is recycled, a noble metal material is required to resist corrosion, the higher the initial concentration of the added mixed acid (about 92% of sulfuric acid) is, the higher the concentration of the acid recycled by the reaction acid is, the higher the recovery temperature in dehydration recycling is, the requirement on system vacuum is high, and after the initial concentration of the mixed acid is high, the concentration of the generated reaction acid is also high (about 86%), organic matters remained in the reaction acid are related to the acid concentration, and the remained in the organic matter reaction acid is also much in the reaction, so that the reaction speed is increased, the reaction time is reduced, and the initial concentration of the mixed acid is reduced by adopting a novel one-stage reactor with high efficiency.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to: (1) The m-nitrobenzotrifluoride synthesis device and the synthesis method can reduce back mixing of materials in a reactor, and timely discharge the generated products and waste acid to enter a heat exchanger, thereby avoiding side reaction of the materials and improving the quality and yield of the reactants; (2) Another object of the present invention is to develop and use a novel nitration first-stage reactor, which reduces the F-concentration in the reaction acid, increases the quality and yield of the nitration and reduces the cost.

In order to solve the above problems, the present invention adopts the following technical solutions.

An m-nitrobenzotrifluoride synthesis device comprises:

the device comprises a primary reactor, a secondary reactor and a stirring mechanism, wherein a feeding mechanism is arranged at the feeding end of the primary reactor, a secondary reactor is arranged at the outlet end of the primary reactor, and the stirring mechanism is arranged in the primary reactor;

the main shaft is rotatably arranged on the other side of the secondary reactor, is mechanically sealed and is connected with the motor, and the main shaft extends into the secondary reactor;

the mixing disc consists of a main disc and an auxiliary disc, is arranged in the secondary reactor, is matched with the main shaft, and is fixedly arranged in the cavity of the secondary reactor and separates the cavity;

the heat exchanger is arranged at the outlet end of the secondary reactor, and the cooling medium of the heat exchanger can be circulating water or refrigerating fluid;

and the separator is fixedly arranged at the outlet end of the heat exchanger.

Further, the feeding mechanism comprises:

the first feeding pipe is fixedly arranged at the upper end of the primary reactor, and one end of the first feeding pipe extends into the primary reactor;

one end of the second feeding pipe is inserted into one end of the first feeding pipe extending into the primary reactor, and the other end of the second feeding pipe extends out of the interior of the first feeding pipe;

and one end of the third feeding pipe is inserted into one end, positioned in the first feeding pipe, of the second feeding pipe, and the other end of the third feeding pipe extends out of the second feeding pipe.

Further, the inside of first inlet pipe, the inside of second inlet pipe and the inside of third inlet pipe all fixed mounting have the flowmeter, the outside of first inlet pipe is equipped with control valve A, the outside of second inlet pipe is equipped with control valve B, the outside of third inlet pipe is equipped with control valve C.

Furthermore, the outside fixed mounting of first order reactor has the cooling tube, the cooling tube is helical structure, the end fixed mounting that intakes of cooling tube has the inlet tube.

Further, the filter mechanism includes:

one end of the discharge pipe is fixedly connected to the lower end of the primary reactor;

the heat exchanger is fixedly arranged on the outer side of the discharge pipe;

and the upper end of the separator is fixedly connected to one end, far away from the primary reactor, of the discharge pipe.

Further, the lower limb fixed mounting in the separator outside has the back flow, the one end fixed connection in the one side of the first order reactor upper end that the separator was kept away from to the back flow, the lower extreme fixed mounting of separator has the reaction acid pipe, the first half fixed mounting in the separator outside has finished product pipe.

Further, through being provided with discharging pipe fixed connection between the discharge end of primary reactor and the feed end of secondary reactor, the inside lower wall of primary reactor is provided with drive gear group, the lower extreme meshing of drive gear group and rotation axis, the lower limb of primary reactor inboard rotates installs the ring gear, the inboard and the drive gear group meshing of ring gear, the upper end fixed mounting of ring gear has the spiral plate, just the outside of spiral plate is laminated in the inboard of primary reactor.

Furthermore, a plurality of flow distribution plates are distributed at one end of the first feeding pipe extending into the first-stage reactor along the circumference in an array mode, and a filter screen is fixedly installed between the outer sides of the two adjacent flow distribution plates.

Furthermore, a water inlet is formed in one end of the heat exchanger, a water outlet is formed in the end, away from the water inlet, of the heat exchanger, and a heat dissipation cavity is formed in the heat exchanger.

A synthetic method of m-nitrobenzotrifluoride comprises the following steps:

s1, proportioning and mixing: respectively conveying trifluorotoluene, concentrated nitric acid and sulfuric acid to the interior of the primary reactor through the first feeding pipe, the second feeding pipe and the third feeding pipe, wherein the molar ratio of mixed acid prepared from the trifluorotoluene, the concentrated nitric acid and the sulfuric acid is 1:1.01 to 1.10:1.5 to 4.0;

s2, stirring and mixing: the transmission gear set and the gear ring in tooth connection with the transmission gear set are driven to rotate through the rotating shaft, the spiral plate on the gear ring rotates along the inner side of the primary reactor, so that a mixture on the inner side of the primary reactor flows upwards or downwards along the edge of the spiral plate, the mixture is fully mixed and reacts, and heat is released;

s3, heat dissipation and cooling: cold water is conveyed into the cooling pipe through the water inlet pipe, and the water flow in the cooling pipe takes away heat outside the primary reactor, so that the primary reactor is conveniently cooled;

s4, product sedimentation: after the mixture in the first-stage reactor is stirred and mixed for a specified time, conveying the reaction product in the first-stage reactor to a separator through the discharge pipe, performing gravity settling on the reaction product in the separator, standing the solution in the separator to obtain a chromatographic solution, obtaining a crude product of m-nitrobenzotrifluoride on the upper layer of the chromatographic solution, and obtaining reaction sulfuric acid on the lower layer of the chromatographic solution;

s5, reaction acid recovery: and finally, discharging the reaction sulfuric acid at the lower layer of the chromatographic solution through the reaction acid pipe, and recycling and utilizing the reaction sulfuric acid.

Compared with the prior art, the invention has the advantages that:

(1) This scheme is through first inlet pipe, second inlet pipe and third inlet pipe to the inside trifluorotoluene of carrying respectively of primary reactor, concentrated nitric acid and sulphuric acid, simultaneously through first inlet pipe, the structural feature that second inlet pipe and third inlet pipe overlap in proper order and establish, trifluorotoluene, concentrated nitric acid and sulphuric acid wrap up along the gradient in proper order, make things convenient for trifluorotoluene, concentrated nitric acid and sulphuric acid are premixed, increase trifluorotoluene, the area of contact between each other of concentrated nitric acid and sulphuric acid, can reduce the degree of difficulty that the mixture mixes in the primary reactor.

(2) According to the scheme, when the first feeding pipe flows into the mixture into the first-stage reactor, the mixture is contacted with the flow distribution plate to be divided into a plurality of strands, so that the volume of the benzotrifluoride, the concentrated nitric acid and the sulfuric acid which are gathered is conveniently reduced, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are easily dispersed and contacted with each other under the action of gravity, then the benzotrifluoride, the concentrated nitric acid and the sulfuric acid flow out along the pores of the filter screens, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are further dispersed through the plurality of filter screens, the surface area of the mixture is increased, combination among different liquid drops is facilitated, combination of different types of liquid drops is promoted, and the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are conveniently contacted and subjected to nitration reaction.

(3) The scheme drives the transmission gear set and the gear ring meshed with the transmission gear set to rotate through the rotating shaft, the spiral plate on the gear ring is rotated along the inner side of the primary reactor, so that the mixture on the inner side of the primary reactor flows along the upper wall or the lower wall of the spiral plate in an inclined manner, the depth of the mixture is changed, the mixture with different depths of the inner wall of the primary reactor is conveniently stirred, the mixtures with different depths are mixed together, the mixture is fully mixed and reacted, heat is released, the mixtures with different depths of the inner wall of the primary reactor can be mixed together, the mixture with the layering phenomenon on the inner wall of the primary reactor is reduced, and the mixture at the inner wall of the primary reactor is fully reacted.

(4) This scheme passes through the motor and drives the main shaft rotation, the main shaft drives the main disc rotation, stir the solution in the second grade reactor cavity, carry the second grade reactor reaction product along the heat exchanger again and give the separator, absorb the partial heat that the product gived off through the heat exchanger simultaneously, make things convenient for the product and the heat dissipation of second grade reactor, can make the contact of the mixture intensive mixing in the second grade reactor cavity, and flow to the ejection of compact side, so that the material reduces back mixing in the reactor, the product and the spent acid of formation in time discharge, get into the heat exchanger, avoid the material to take place side reaction, improve reaction mass and yield.

(5) The reaction acid pipe is used for discharging the reaction sulfuric acid on the lower layer of the chromatographic solution, the reaction sulfuric acid is recycled and utilized, the reaction of the primary reactor is facilitated, and the reaction product is subjected to gravity settling at the same time, compared with the multi-kettle series continuous reaction and the intermittent kettle type reaction, the primary reactor has the same composition of the obtained mixed nitro-compound finished product, and the reaction time is shortened to 10-15 minutes from 1 hour of the multi-kettle series connection. The liquid holdup of the reaction system is reduced from more than ten thousand liters to about 150 liters, and the method has the advantages of high product yield, safety, environmental protection, good productivity and stable quality.

Drawings

FIG. 1 is a schematic structural view of a front view of the present invention;

FIG. 2 is a schematic top view of the present invention;

FIG. 3 is a schematic cross-sectional view of the present invention;

FIG. 4 is an enlarged schematic view of the invention at A of FIG. 1;

FIG. 5 is an enlarged view of the structure of FIG. 2 at B according to the present invention;

FIG. 6 is an enlarged view of the structure of FIG. 3 at C according to the present invention;

FIG. 7 is an enlarged view of FIG. 3 at D in accordance with the present invention;

FIG. 8 is a flow chart of a synthetic method of the present invention;

fig. 9 is an enlarged schematic view of the structure at E in fig. 3 according to the present invention.

The reference numbers in the figures illustrate:

1. a first stage reactor; 2. a rotating shaft; 3. a drive gear set; 4. a ring gear; 5. a spiral plate; 6. a first feed tube; 7. a second feed tube; 8. a third feed pipe; 9. a flow meter; 10. a control valve A; 11. a control valve B; 12. a control valve C; 13. a cooling tube; 14. a water inlet pipe; 15. a discharge pipe; 16. a heat exchanger; 17. a separator; 18. a return pipe; 19. a reaction acid tube; 20. a finished product pipe; 21. a fan blade; 22. a cylinder; 23. a rotating seat; 24. a packing auger; 25. a flow distribution plate; 26. filtering with a screen; 27. a water inlet; 28. a water outlet; 29. a heat dissipation cavity; 30. a control valve D; 31. a water valve; 32. a secondary reactor; 33. a main shaft; 34. and (4) a mixing disc.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work are within the scope of the present invention.

Example (b):

referring to fig. 1-9, an apparatus for synthesizing m-nitrobenzotrifluoride includes:

a feeding mechanism is arranged at the feeding end of the primary reactor 1, a secondary reactor 32 is arranged at the outlet end of the primary reactor 1, and a stirring mechanism is arranged inside the primary reactor 1;

the feed mechanism includes:

the first feeding pipe 6 is fixedly arranged at the upper end of the primary reactor 1, and one end of the first feeding pipe 6 extends into the primary reactor 1;

one end of the second feeding pipe 7 is inserted into one end of the first feeding pipe 6 extending into the primary reactor 1, and the other end of the second feeding pipe 7 extends out of the first feeding pipe 6;

a third feeding pipe 8, one end of the third feeding pipe 8 is inserted into one end of the second feeding pipe 7 inside the first feeding pipe 6, and the other end of the third feeding pipe 8 extends out of the second feeding pipe 7.

When the device works, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are respectively conveyed into the primary reactor 1 through the first feeding pipe 6, the second feeding pipe 7 and the third feeding pipe 8, and meanwhile, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are sequentially wrapped along a gradient through the structural characteristics of the first feeding pipe 6, the second feeding pipe 7 and the third feeding pipe 8 in a sleeving manner, so that the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are conveniently premixed, the contact area among the benzotrifluoride, the concentrated nitric acid and the sulfuric acid is increased, and the difficulty of mixing the mixture in the primary reactor 1 can be reduced.

Referring to fig. 3 and 7, a plurality of flow distribution plates 25 are further distributed along a circumferential array at one end of the first feeding pipe 6 extending into the primary reactor 1, a filter screen 26 is fixedly installed between the outer sides of two adjacent flow distribution plates 25, when the first feeding pipe 6 flows into the primary reactor 1, the mixture contacts with the flow distribution plates 25 to be divided into a plurality of strands, so that the volume of the benzotrifluoride, the concentrated nitric acid and the sulfuric acid is conveniently reduced, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are easily dispersed and contacted with each other under the action of gravity, then the benzotrifluoride, the concentrated nitric acid and the sulfuric acid flow out along the pores of the filter screen 26, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are further dispersed through the plurality of filter screens 26, the surface area of the mixture is increased, the combination of different droplets is convenient, the combination of different kinds of droplets is promoted, and the contact of the benzotrifluoride, the concentrated nitric acid and the sulfuric acid and the nitration reaction are conveniently performed.

Referring to fig. 1, 3 and 5, flow meters 9 are fixedly installed inside the first feeding pipe 6, inside the second feeding pipe 7 and inside the third feeding pipe 8, one end of each flow meter 9 is provided with a wireless communication module, the technical scheme is the prior art, which is not shown in the figure, a control valve a10 is installed outside the first feeding pipe 6, a control valve B11 is installed outside the second feeding pipe 7, and a control valve C12 is installed outside the third feeding pipe 8, when the first feeding pipe 6, the second feeding pipe 7 and the third feeding pipe 8 need to be fed, the control valve a10, the control valve B11 and the control valve C12 are opened, and then the flow rates in the first feeding pipe 6, the second feeding pipe 7 and the third feeding pipe 8 are respectively monitored through the three flow meters 9 until the flow rates reach a preset value, so as to timely close the control valve a10, the control valve B11 and the control valve C12.

Referring to fig. 2, 3 and 4, a discharge end of a first-stage reactor 1 is fixedly connected with a feed end of a second-stage reactor 32 through a discharge pipe 15, a water valve 31 is assembled outside the discharge pipe 15, a transmission gear set 3 is arranged on a lower wall inside the first-stage reactor 1, the transmission gear set 3 is meshed with a lower end of a rotating shaft 2, a gear ring 4 is rotatably installed on a lower edge of an inner side of the first-stage reactor 1, an inner side of the gear ring 4 is meshed with the transmission gear set 3, a spiral plate 5 is fixedly installed on an upper end of the gear ring 4, and an outer side of the spiral plate 5 is attached to an inner side of the first-stage reactor 1.

When the device works, the transmission gear set 3 and the gear ring 4 in tooth connection with the transmission gear set 3 are driven to rotate by the rotating shaft 2, the spiral plate 5 on the gear ring 4 rotates along the inner side of the first-stage reactor 1, so that the mixture on the inner side of the first-stage reactor 1 obliquely flows along the upper wall or the lower wall of the spiral plate 5, the depth of the mixture is changed, the mixture with different depths on the inner wall of the first-stage reactor 1 is conveniently stirred, the mixture with different depths is mixed together and fully mixed and reacts, heat is released, the mixture with different depths on the inner wall of the first-stage reactor 1 can be mixed together, the mixture with the layering phenomenon on the inner wall of the first-stage reactor 1 is reduced, the mixture on the inner wall of the first-stage reactor 1 is fully reacted, finally, the water valve 31 is opened, and the product in the first-stage reactor 1 is conveyed into the second-stage reactor 32 through the discharge pipe 15.

Referring to fig. 2, 3 and 9, the main shaft 33 is rotatably installed at the other side of the secondary reactor 32, has a mechanical seal, and is connected with the motor, and the main shaft 33 extends into the secondary reactor 32;

the mixing disc 34 is composed of a main disc and an auxiliary disc, the mixing disc 34 is installed inside the secondary reactor 32, the main disc is matched with the main shaft 33, and the auxiliary disc is fixedly installed in a cavity of the secondary reactor 32 and separates the cavity;

the heat exchanger 16 is arranged at the outlet end of the secondary reactor 32, and the cooling medium of the heat exchanger 16 can be circulating water or refrigerating fluid;

and the separator 17, wherein the separator 17 is fixedly arranged at the outlet end of the heat exchanger 16.

When the secondary reactor 32 cooling device works, the motor drives the main shaft 33 to rotate, the main shaft 33 drives the main disc to rotate, the solution in the cavity of the secondary reactor 32 is stirred, the reaction product of the secondary reactor 32 is conveyed to the separator 17 along the heat exchanger 16, meanwhile, the heat exchanger 16 absorbs part of heat emitted by the product, the product and the secondary reactor 32 are convenient to cool, the mixture in the cavity of the secondary reactor 32 can be fully mixed and contacted and flows to the discharging side, the material in the reactor is reduced from back mixing, the generated product and waste acid are timely discharged and enter the heat exchanger 16, the side reaction of the material is avoided, and the quality and the yield of the reaction are improved.

Referring to fig. 3 and 6, the agitating mechanism includes:

the fan blades 21 are distributed on the outer side of the rotating shaft 2 along a vertical array, and the fan blades 21 in each group are distributed along a circumference array;

one end of the air cylinder 22 is fixedly connected to the outer side of the rotating shaft 2, and the height of the air cylinder 22 is greater than that of the fan blades 21;

one side of the rotating seat 23 is fixedly connected with the output end of the air cylinder 22;

the packing auger 24, the upper end of packing auger 24 rotates and connects the lower extreme that rotates seat 23, rotates and is equipped with the brake motor that is used for rotatory packing auger 24 on the seat 23, and this technical scheme is prior art, does not show in the drawing.

When the device works, the rotating shaft 2 drives the fan blade 21 and the air cylinder 22 to rotate, the auger 24 on the rotating base 23 rotates around the rotating base 23 under the driving of the brake motor, the fan blade 21 and the auger 24 stir the mixture in the primary reactor 1 in the water direction, the auger 24 drives the mixture to move upwards or downwards, so that the mixtures with different depths are mixed together, and the air cylinder 22 can push the auger 24 to move horizontally to change the horizontal position of the auger 24 in the primary reactor 1, so that the auger 24 can conveniently stir the mixture in a larger area.

Referring to fig. 1, 2 and 3, a cooling pipe 13 is fixedly installed on the outer side of the primary reactor 1, the cooling pipe 13 is of a spiral structure, and a water inlet pipe 14 is fixedly installed on the water inlet end of the cooling pipe 13, when the invention works, cold water is conveyed into the cooling pipe 13 through the water inlet pipe 14, and the water flow in the cooling pipe 13 takes away the heat on the outer side of the primary reactor 1, so that the primary reactor 1 is conveniently cooled and dissipated, and the temperature of nitration reaction in the primary reactor 1 is controlled within the range of 40-90 ℃.

Referring to fig. 1 and 3, a water inlet 27 is formed at one end of the heat exchanger 16, a water outlet 28 is formed at one end of the heat exchanger 16 away from the water inlet 27, a heat dissipation chamber 29 is formed inside the heat exchanger 16, when the product flows through the discharge pipe 15, cold water is input into the heat dissipation chamber 29 through the water inlet 27, heat of the discharge pipe 15 and heat of the product are taken away through the heat dissipation chamber 29, heat dissipation of the product and the discharge pipe 15 is facilitated, and hot water in the heat exchanger 16 is discharged through the water inlet 27.

Referring to fig. 2, 3 and 4, a return pipe 18 is fixedly installed on the lower edge of the outer side of the separator 17, one end of the return pipe 18, which is far away from the separator 17, is fixedly connected to one side of the upper end of the first-stage reactor 1, a control valve D30 is installed on the outer side of the return pipe 18, a reaction acid pipe 19 is fixedly installed at the lower end of the separator 17, a product pipe 20 is fixedly installed on the upper half of the outer side of the separator 17, when a product enters the separator 17, the product is subjected to gravity settling through the separator 17, a solution in the separator 17 is kept standing into a chromatographic solution, a crude product of m-nitrobenzotrifluoride is obtained on the upper layer of the chromatographic solution, a lower layer of the chromatographic solution is obtained to be reaction sulfuric acid, the concentration of F of the reaction sulfuric acid is lower than 200ppm, the reaction sulfuric acid is concentrated and recovered to obtain 88 to 92% of sulfuric acid, and the amount of the sulfuric acid is returned to a reaction system, the amount of nitric acid can be reduced by 2 to 3% compared with a multi-kettle series process, the amount of the invention, the waste gas is less, the alkali consumption of the absorbed waste gas is less, and the waste water is less.

The device comprises a primary reactor 1, a rotating shaft 2, a transmission gear set 3, a gear ring 4, a spiral plate 5, a first feeding pipe 6, a second feeding pipe 7, a third feeding pipe 8, a flowmeter 9, a control valve A10, a control valve B11, a control valve C12, a discharging pipe 15, a heat exchanger 16, a separator 17, a return pipe 18, a reaction acid pipe 19, a finished product pipe 20, fan blades 21, an air cylinder 22, a rotating seat 23, a packing auger 24, a flow distribution plate 25, a filter screen 26, a control valve D30 and a water valve 31 which are all coated with tetrafluoroethylene coatings and used for relieving the corrosion effect of strong acid in a mixture.

Referring to fig. 8, a method for synthesizing m-nitrobenzotrifluoride includes the following steps:

s1, proportioning and mixing: respectively conveying trifluorotoluene, concentrated nitric acid and sulfuric acid into the primary reactor 1 through a first feeding pipe 6, a second feeding pipe 7 and a third feeding pipe 8, wherein the molar ratio of mixed acid prepared from the trifluorotoluene, the concentrated nitric acid and the sulfuric acid is 1:1.01 to 1.10: 1.5-4.0, the concentration of the concentrated nitric acid is 98%, and meanwhile, through the structural characteristics that the first feeding pipe 6, the second feeding pipe 7 and the third feeding pipe 8 are sequentially sleeved, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are sequentially wrapped along a gradient, so that the pre-mixing of the benzotrifluoride, the concentrated nitric acid and the sulfuric acid is facilitated, the contact area among the benzotrifluoride, the concentrated nitric acid and the sulfuric acid is increased, the difficulty of mixing the mixture in the primary reactor 1 can be reduced, when the first feeding pipe 6 flows into the primary reactor 1, the mixture is in contact with the splitter plate 25 to be divided into a plurality of strands, so that the volume of the benzotrifluoride, the concentrated nitric acid and the sulfuric acid is conveniently reduced, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are easily dispersed and are in contact with each other under the action of gravity, then the benzotrifluoride, the concentrated nitric acid and the sulfuric acid flow out along the pores of the filter screen 26, the benzotrifluoride, the concentrated nitric acid and the sulfuric acid are further dispersed through the plurality of the filter screens 26, the surface area of the mixture is increased, so that the combination among different liquid drops is facilitated, the combination of different liquid drops, the different types of the benzotrifluoride, and the nitration reaction is facilitated;

s2, stirring and mixing: the transmission gear set 3 and the gear ring 4 in tooth connection with the transmission gear set 3 are driven to rotate through the rotating shaft 2, the rotating speed of the rotating shaft 2 is 1450rpm to 2900rpm, the spiral plate 5 on the gear ring 4 rotates along the inner side of the first-stage reactor 1, so that the mixture in the inner side of the first-stage reactor 1 flows along the upper wall or the lower wall of the spiral plate 5 in an inclined mode, the depth of the mixture is changed, the mixture is fully mixed and reacts, and heat is released;

s3, heat dissipation and cooling: cold water is conveyed into the cooling pipe 13 through the water inlet pipe 14, and the water flow in the cooling pipe 13 takes away the heat outside the primary reactor 1, so that the primary reactor 1 is conveniently cooled, and the temperature of the nitration reaction in the primary reactor 1 is controlled within the range of 40-90 ℃;

s4, product sedimentation: after the mixture in the first-stage reactor 1 is stirred and mixed for a specified time, the reaction product in the first-stage reactor 1 is conveyed to a separator 17 through a discharge pipe 15, the reaction product is subjected to gravity settling in the separator 17, the solution in the separator 17 is kept stand to form a chromatographic solution, the upper layer of the chromatographic solution is a crude product of m-nitrobenzotrifluoride, and the lower layer of the chromatographic solution is reaction sulfuric acid;

s5, recovering reaction acid: and finally, discharging the reaction sulfuric acid at the lower layer of the chromatographic solution through a reaction acid pipe 19, recovering and utilizing the reaction sulfuric acid, facilitating the reaction of the primary reactor 1 and simultaneously performing gravity settling on a reaction product, wherein compared with the multi-kettle series continuous reaction and the batch kettle type reaction, the composition of the obtained mixed nitro-compound finished product is the same, and the reaction time is shortened to 10-15 minutes from 1 hour of the multi-kettle series connection. The liquid holdup of the reaction system is reduced from more than ten thousand liters to about 150 liters, and the method has the advantages of high product yield, safety, environmental protection, good productivity and stable quality.

The foregoing is only a preferred embodiment of the present invention; the scope of the invention is not limited thereto. Any person skilled in the art should be able to cover the technical scope of the present invention by equivalent or modified solutions and modifications within the technical scope of the present invention.

Claims (10)

1. The m-nitrobenzotrifluoride synthesis device is characterized by comprising:

the device comprises a primary reactor (1), wherein a feeding mechanism is arranged at the feeding end of the primary reactor (1), a secondary reactor (32) is arranged at the outlet end of the primary reactor (1), and a stirring mechanism is arranged in the primary reactor (1);

the main shaft (33) is rotatably arranged on the other side of the secondary reactor (32), is mechanically sealed and is connected with the motor, and the main shaft (33) extends into the secondary reactor (32);

the mixing disc (34) consists of a main disc and an auxiliary disc, the mixing disc (34) is arranged in the secondary reactor (32), the main disc is matched with the main shaft (33), and the auxiliary disc is fixedly arranged in a cavity of the secondary reactor (32) and separates the cavity;

the heat exchanger (16), the heat exchanger (16) is installed at the outlet end of the secondary reactor (32), and the cooling medium of the heat exchanger (16) can be circulating water or refrigerating fluid;

and the separator (17), wherein the separator (17) is fixedly arranged at the outlet end of the heat exchanger (16).

2. The m-nitrobenzotrifluoride synthesis device according to claim 1, characterized in that: the feed mechanism includes:

the first feeding pipe (6), the first feeding pipe (6) is fixedly arranged at the upper end of the primary reactor (1), and one end of the first feeding pipe (6) extends into the primary reactor (1);

one end of the second feeding pipe (7) is inserted into one end of the first feeding pipe (6) extending into the primary reactor (1), and the other end of the second feeding pipe (7) extends out of the first feeding pipe (6);

the device comprises a third feeding pipe (8), one end of the third feeding pipe (8) is inserted into one end, located inside the first feeding pipe (6), of the second feeding pipe (7), and the other end of the third feeding pipe (8) extends out of the inside of the second feeding pipe (7).

3. The m-nitrobenzotrifluoride synthesis device according to claim 2, characterized in that: the inside of first inlet pipe (6), the inside of second inlet pipe (7) and the inside of third inlet pipe (8) all fixed mounting have flowmeter (9), the outside of first inlet pipe (6) is equipped with control valve A (10), the outside of second inlet pipe (7) is equipped with control valve B (11), the outside of third inlet pipe (8) is equipped with control valve C (12).

4. The m-nitrotrifluorotoluene synthesis apparatus according to claim 1, wherein: the outer side of the primary reactor (1) is fixedly provided with a cooling pipe (13), the cooling pipe (13) is of a spiral structure, and the water inlet end of the cooling pipe (13) is fixedly provided with a water inlet pipe (14).

5. The m-nitrobenzotrifluoride synthesis device according to claim 1, characterized in that: the agitation mechanism includes:

the rotating shaft (2), the rotating shaft (2) is rotatably installed in the middle of the upper wall of the primary reactor (1);

the fan blades (21) are distributed on the outer side of the rotating shaft (2) along a vertical array, and the fan blades (21) are distributed along a circumference array;

the air cylinder (22), one end of the air cylinder (22) is fixedly connected to the outer side of the upper end of the rotating shaft (2), and the height of the air cylinder (22) is greater than that of the fan blades (21);

one side of the rotating seat (23) is fixedly connected with the output end of the air cylinder (22); the upper end of the packing auger (24) is rotatably connected with the lower end of the rotating seat (23).

6. The m-nitrotrifluorotoluene synthesis apparatus according to claim 1, wherein: the lower limb fixed mounting in separator (17) outside has back flow (18), the one end fixed connection in one side of first order reactor (1) upper end that separator (17) were kept away from in back flow (18), the lower extreme fixed mounting of separator (17) has reaction acid pipe (19), the first fixed mounting in separator (17) outside has finished product pipe (20).

7. The m-nitrobenzotrifluoride synthesis device according to claim 1, characterized in that: through being provided with discharging pipe (15) fixed connection between the discharge end of primary reactor (1) and the feed end of secondary reactor (32), the inside lower wall of primary reactor (1) is provided with drive gear group (3), the lower extreme meshing of drive gear group (3) and rotation axis (2), ring gear (4) are installed in the lower limb rotation of primary reactor (1) inboard, the inboard and the drive gear of ring gear (4) organize (3) meshing, the upper end fixed mounting of ring gear (4) has spiral plate (5), just the outside of spiral plate (5) is laminated in the inboard of primary reactor (1).

8. The m-nitrobenzotrifluoride synthesis device according to claim 2, characterized in that: the first feeding pipe (6) extends into the inside one end of the first-stage reactor (1) and is further provided with a plurality of flow distribution plates (25) along the circumferential array, and a filter screen (26) is fixedly arranged between the two adjacent outer sides of the flow distribution plates (25).

9. The m-nitrobenzotrifluoride synthesis device according to claim 5, wherein: a water inlet (27) is formed in one end of the heat exchanger (16), a water outlet (28) is formed in one end, far away from the water inlet (27), of the heat exchanger (16), and a heat dissipation cavity (29) is formed in the heat exchanger (16).

10. A method for synthesizing m-nitrobenzotrifluoride is characterized by comprising the following steps: the m-nitrobenzotrifluoride synthesis device applied to any one of claims 1-9, wherein the synthesis method comprises the following steps:

s1, proportioning and mixing: respectively conveying trifluorotoluene, concentrated nitric acid and sulfuric acid to the interior of the primary reactor (1) through the first feeding pipe (6), the second feeding pipe (7) and the third feeding pipe (8), wherein the molar ratio of mixed acid prepared from the trifluorotoluene, the concentrated nitric acid and the sulfuric acid is 1:1.01 to 1.10:1.5 to 4.0;

s2, stirring and mixing: the transmission gear set (3) and the gear ring (4) in tooth joint with the transmission gear set (3) are driven to rotate through the rotating shaft (2), the spiral plate (5) on the gear ring (4) rotates along the inner side of the primary reactor (1), so that a mixture on the inner side of the primary reactor (1) flows upwards or downwards along the edge of the spiral plate (5), the mixture is fully mixed and reacts, and heat is released;

s3, heat dissipation and cooling: cold water is conveyed into the cooling pipe (13) through the water inlet pipe (14), and water flow in the cooling pipe (13) takes away heat outside the primary reactor (1), so that the primary reactor (1) is conveniently cooled;

s4, product sedimentation: after the mixture in the primary reactor (1) is stirred and mixed for a specified time, the reaction product in the primary reactor (1) is conveyed to a separator (17) through the discharge pipe (15), the reaction product is subjected to gravity settling in the separator (17), the solution in the separator (17) is kept still to be chromatographic liquid, the upper layer of the chromatographic liquid is used for obtaining a crude product of m-nitrobenzotrifluoride, and the lower layer of the chromatographic liquid is used for obtaining reaction sulfuric acid;

s5, reaction acid recovery: finally, the reaction sulfuric acid in the lower layer of the chromatography liquid is discharged through the reaction acid tube (19), and the reaction sulfuric acid is recovered and used.

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