CN116272769A - Production method and production device of micro-mixed tube type reaction nitrified toluene - Google Patents

Production method and production device of micro-mixed tube type reaction nitrified toluene Download PDF

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CN116272769A
CN116272769A CN202211094180.5A CN202211094180A CN116272769A CN 116272769 A CN116272769 A CN 116272769A CN 202211094180 A CN202211094180 A CN 202211094180A CN 116272769 A CN116272769 A CN 116272769A
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reaction
toluene
micro
temperature
sulfuric acid
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侯云辉
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Hubei Dongfang Chemical Industry Co ltd
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Hubei Dongfang Chemical Industry Co ltd
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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
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/18—Stationary reactors having moving elements inside
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/0013—Controlling the temperature of the process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B01J19/006—Baffles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B01J19/0066—Stirrers
    • 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
    • B01J4/00—Feed or outlet devices; Feed or outlet control devices
    • B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/06—Preparation of nitro compounds
    • C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/06—Preparation of nitro compounds
    • C07C201/16—Separation; Purification; Stabilisation; Use of additives
    • 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
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00076—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements inside the reactor
    • B01J2219/00085—Plates; Jackets; Cylinders
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

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  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention discloses a production method and a production device of micro-mixed tubular reaction nitrotoluene, which realize flexible synthesis of mononitrotoluene and dinitrotoluene through a set of reaction devices, abandon the traditional continuous kettle type reaction, increase the heat exchange area so as to improve the heat efficiency, avoid the need of maintaining the low-temperature reaction process to control the generation of impurities, avoid explosion caused by out-of-control temperature of a reaction system, and improve the production safety; the medium can enter the heat conducting pipe through a plurality of through pipes after entering the cavity, and the heat conducting area is increased by a plurality of heat conducting fins arranged in the heat conducting pipe, and the movement direction of the fluid changes due to the protruding shape in the heat conducting pipe, so that the fluid is concentrated with the middle part in the jacket pipe, even if the fluid flux rises, good mixing effect can still be ensured, further, the heat conducting fins are matched in the process of conducting cold and heat, the purposes of efficient mixing and cold and heat conduction can be kept on the basis of high flux, and the production and the preparation of products are facilitated.

Description

Production method and production device of micro-mixed tube type reaction nitrified toluene
Technical Field
The invention belongs to the technical field of chemical production, and particularly relates to a production method and a production device of micro-mixed tube reaction nitrified toluene.
Background
Toluene nitration is an important reaction in the chemical industry, and its nitration products include mononitrotoluene, dinitrotoluene and trinitrotoluene, and mononitrotoluene is an important fine chemical intermediate, including three isomers of ortho-nitrotoluene, meta-nitrotoluene and para-nitrotoluene, and is widely used in the industries of medicine, pesticides, dyes, etc. For example, para-nitrotoluene is used to make DSD acid, para-methylaniline and TNT, ortho-nitrotoluene is used to make ortho-methylaniline and TNT, and meta-nitrotoluene is used to make meta-methylaniline. Dinitrotoluene is mainly used for preparing dyes, paints and coatings, and is also a precursor for producing explosives and toluene diisocyanate. Trinitrotoluene is widely used as a first type of elemental explosive.
At present, the industrial production of mononitrotoluene and dinitrotoluene in China mainly adopts an intermittent or continuous kettle type process, a ring type nitration process of a French Mesona company, a normal pressure heat insulation and pressurizing heat insulation nitration process of a American cyanamide company, a pump type nitration process of a Norbeol company, a tubular heat insulation nitration process of a Germany Bayer company, a preparation process of mononitroaromatic compounds of triple well chemistry, and a toluene nitration reaction is carried out by adopting a static mixer, a micro mixer or a micro channel reactor of various types to carry out the toluene nitration reaction in the beginning of a micro reaction technology in the 21 st century.
The following problems exist in the continuous kettle type toluene nitration reaction:
1. in kettle type nitrification, equipment is huge and complex, the liquid holdup of a reaction kettle is large, and when danger is generated, the danger is large.
2. The reaction kettle has smaller heat exchange area and low heat exchange efficiency, is not matched with the rapid nitration reaction with high reaction heat, and requires relatively mild acid condition to reduce the intrinsic rate so as to be matched with the heat transfer rate of the reactor.
3. The reaction kettle adopts an inner coil pipe to increase the heat exchange area, and the low-temperature reaction process is maintained to control the generation of impurities.
4. Once the heat exchange system of the reaction kettle is in mechanical or other faults to stop working, the temperature of the reaction system can be immediately out of control to cause explosion.
Furthermore, in the process of using the tubular reactor to carry out the corresponding chemical reaction on the fluid interactive mixing, and when the tubular reactor with the straight tubular design is used for carrying out the mixing reaction, along with the rising of the fluid flux, the mixing effect is influenced due to the too fast flow speed, and meanwhile, the process of carrying out the cold and heat conduction is also influenced, so that the problem of how to keep the efficient mixing and the cold and heat conduction on the basis of high flux is the problem to be solved at present.
Disclosure of Invention
(one) solving the technical problems
In order to overcome the defects in the prior art, the invention provides a production method and a production device for micro-mixed tubular reaction nitrified toluene, and solves the problems in the background art.
(II) technical scheme
In order to achieve the above purpose, the present invention provides the following technical solutions: a production method and a production device of micro-mixed tube reaction nitrified toluene, wherein the production method comprises the following steps:
a) Preparation of mononitrotoluene
(1) Diluting the concentrated sulfuric acid with the mass percent concentration of 98% into dilute sulfuric acid with the mass percent concentration of 65% -75%.
(2) Adding 98% of concentrated nitric acid into the dilute sulfuric acid solution in the step (1) to prepare the aqueous solution.
The molar ratio of the nitric acid to the sulfuric acid solution, namely the mixed acid solution, is 0.1-0.5.
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1-1.1): 1, controlling the temperature of the material conveying pipe in a water bath to be 30-50 ℃.
Stirring reaction is carried out in a tubular reactor, the reaction temperature is controlled to be 40-100 ℃, and the stirring rotation speed is 200-350rad/min, so as to obtain reactant solution.
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and performing alkali washing and water washing on the organic phase until the organic phase is neutral, thus obtaining the mononitrotoluene.
When the DNT concentration in the product is allowed to exceed 1%, the tubular reactor adopts heat insulation, the heat generated by the reaction is fully utilized, the reaction temperature reaches 90-100 ℃, the energy is saved, the reaction efficiency is improved, the dilute sulfuric acid concentration is optimally controlled to 73-75%, and the molar ratio of nitric acid to toluene is optimally controlled to be (1.05-1.1): 1.
when the DNT concentration in the product is allowed to be not more than 1%, the tubular reactor adopts temperature control, the reaction temperature is controlled to be 40-50 ℃, the dilute sulfuric acid concentration is optimally controlled to be 71-73%, and the molar ratio of nitric acid to toluene is (1.02-1.05): 1, thus controlling the reaction intensity and ensuring that MNT is not excessively nitrified into DNT in the later stage of the reaction.
B) Preparation of dinitrotoluene
(1) Diluting the concentrated sulfuric acid with the mass percent concentration of 98% into dilute sulfuric acid with the mass percent concentration of 75% -85%.
(2) Adding 98% of concentrated nitric acid into the dilute sulfuric acid solution in the step (1) to prepare the aqueous solution.
The molar ratio of the nitric acid to the sulfuric acid solution, namely the mixed acid solution, is 0.5-1.
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1.9-2.4): 1, the temperature of a material conveying pipe is controlled to be 40-60 ℃ in a water bath, stirring reaction is carried out in a tubular reactor, the reaction temperature is controlled to be 40-100 ℃, and the stirring rotation speed is 200-350rad/min, so that a reactant solution is obtained.
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and washing and drying the organic phase to obtain the dinitrotoluene.
A production method and a production device of micro-mixed tube reaction nitrified toluene, wherein the production device comprises the following steps:
A. b and H are storage bottles respectively, C is fluid conveying equipment, specifically a horizontal pump, D is a constant-temperature water bath, E is a micromixer, F is a tubular reactor, and G is a temperature sensor.
According to the material setting proportion, materials are simultaneously conveyed into a micromixer E for premixing through a constant-temperature water bath kettle D from a storage bottle A and a storage bottle B through a fluid conveying device C after temperature control, the materials comprise mixed acid and toluene and react in a tubular reactor F, the tubular reactor F adjusts stirring rotation speed, the temperature of the tubular reactor is controlled through jacket cooling water or the outside of the tubular reactor is kept warm through a heat insulation material to achieve the heat insulation effect, the tubular reactor is connected with a temperature sensor G for displaying the temperature in a segmented mode, reaction liquid after the reaction is stored in the storage bottle H, liquid separation treatment is carried out after the reaction liquid is cooled to room temperature, and an organic phase is a product.
As a further aspect of the invention: the micro-mixer is specifically a T-shaped micro-mixer and comprises a micro-channel plate, three micro-channels positioned on the micro-channel plate, namely two inlet channels and a mixing channel connected with the inlet channels respectively, wherein the inlet channels are connected with two inlet ends respectively, the mixing channel is connected with an outlet end, the two inlet channels are positioned on two sides of the micro-channel plate respectively, the residence time of reaction materials in the micro-mixer is extremely short, and the mixing effect of toluene and mixed acid is enhanced.
As a further aspect of the invention: the tubular reactor comprises a jacket pipe, a plurality of mounting holes are formed in two ends of the jacket pipe, a cavity is formed in the jacket pipe, the cavity is communicated with two medium inlet and outlet valve bodies, two valve pipes are clamped outside the jacket pipe, the valve pipes penetrate through the cavity, a mixing assembly is arranged in the jacket pipe, six heat conducting assemblies are arranged outside the mixing assembly, the six heat conducting assemblies are clamped on a heat conducting liner, and the heat conducting liner is clamped in the jacket pipe.
As a further aspect of the invention: the mixing assembly comprises two brackets, the brackets are fixed with the inner phase of the jacket pipe, the same stirring paddle is arranged between the two brackets, two stirring wings are arranged outside the stirring paddle, and three paddles are arranged outside the stirring wings.
As a further aspect of the invention: the stirring direction of the paddles is clockwise and downward, the reaction liquid is driven to be mixed and advance, and three paddles form a 120-degree circular row for one circle.
As a further aspect of the invention: the heat conduction assembly comprises a heat conduction pipe which is clamped on the heat conduction liner, a plurality of heat conduction sheets are arranged in the heat conduction pipe, and the heat conduction pipe is communicated with the cavity through four through pipes.
(III) beneficial effects
Compared with the prior art, the invention has the beneficial effects that:
1. in the invention, two mutually-incompatible reactant materials of toluene and nitro-sulfur mixed acid are respectively conveyed by a liquid horizontal pump; a constant temperature water bath, preheat two kinds of material pipelines, control reaction initial temperature, and realize the premix of two kinds of materials, the tubular reactor of reuse carries out normal atmospheric temperature, accuse temperature or adiabatic stirring reaction, can realize the flexible synthesis of mononitrotoluene and dinitrotoluene through a set of reaction unit, abandon the tradition and adopt continuous cauldron formula to react, thereby increase heat transfer area improves thermal efficiency, need not to maintain the production that low temperature reaction process controlled impurity, avoid the temperature of reaction system to appear out of control and arouse the explosion, improve production safety.
2. According to the invention, the cavity is arranged in the jacket pipe and used for controlling the medium to enter and exit, the medium can enter the heat conducting pipe through the plurality of through pipes after entering the cavity, the heat conducting area is increased by the plurality of heat conducting fins arranged in the heat conducting pipe, and the movement direction of the fluid is changed to be centralized with the middle part in the jacket pipe due to the protruding shape in the heat conducting pipe, so that even if the fluid flux rises, good mixing effect can be ensured, and furthermore, the heat conducting fins are matched in the process of conducting cold and heat, so that the purposes of high-efficiency mixing and conducting cold and heat can be kept on the basis of high flux, and the production and the preparation of products are facilitated.
Drawings
FIG. 1 is a schematic flow chart of the micro-mixed tube reaction nitrifying toluene;
FIG. 2 is a schematic view of a micro-mixer microchannel plate according to the present invention;
FIG. 3 is a schematic view of the jacket pipe structure of the pipe reactor of the present invention;
FIG. 4 is a schematic cross-sectional view of a jacket sleeve according to the present invention;
FIG. 5 is a schematic view of a cross-section of a jacket sleeve and a heat conductive liner of the present invention;
FIG. 6 is a schematic structural view of a heat conduction assembly according to the present invention;
in the figure: 1. clamping the sleeve; 2. a mounting hole; 3. a cavity; 4. a valve tube; 5. medium in-out valve body; 6. a mixing assembly; 601. a bracket; 602. stirring paddles; 603. stirring wings; 604. a paddle; 7. a heat conducting component; 701. a heat conduction pipe; 702. a through pipe; 703. a heat conductive sheet; 8. a heat conductive liner; 100. a microchannel plate; 200. an inlet channel; 300. an inlet end; 400. a mixing channel; 500. an outlet end.
Detailed Description
The technical scheme of the patent is further described in detail below with reference to the specific embodiments.
As shown in fig. 1-6, the present invention provides a technical solution: a production method and a production device of micro-mixed tube reaction nitrified toluene, wherein the production method comprises the following steps:
a) Preparation of mononitrotoluene
(1) Diluting the concentrated sulfuric acid with the mass percent concentration of 98% into dilute sulfuric acid with the mass percent concentration of 65% -75%.
(2) Adding 98% of concentrated nitric acid into the dilute sulfuric acid solution in the step (1) to prepare the aqueous solution.
The molar ratio of the nitric acid to the sulfuric acid solution, namely the mixed acid solution, is 0.1-0.5.
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1-1.1): 1, controlling the temperature of the material conveying pipe in a water bath to be 30-50 ℃.
Stirring reaction is carried out in a tubular reactor, the reaction temperature is controlled to be 40-100 ℃, and the stirring rotation speed is 200-350rad/min, so as to obtain reactant solution.
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and performing alkali washing and water washing on the organic phase until the organic phase is neutral, thus obtaining the mononitrotoluene.
When the DNT concentration in the product is allowed to exceed 1%, the tubular reactor adopts heat insulation, the heat generated by the reaction is fully utilized, the reaction temperature reaches 90-100 ℃, the energy is saved, the reaction efficiency is improved, the dilute sulfuric acid concentration is optimally controlled to 73-75%, and the molar ratio of nitric acid to toluene is optimally controlled to be (1.05-1.1): 1.
when the DNT concentration in the product is allowed to be not more than 1%, the tubular reactor adopts temperature control, the reaction temperature is controlled to be 40-50 ℃, the dilute sulfuric acid concentration is optimally controlled to be 71-73%, and the molar ratio of nitric acid to toluene is (1.02-1.05): 1, thus controlling the reaction intensity and ensuring that MNT is not excessively nitrified into DNT in the later stage of the reaction.
B) Preparation of dinitrotoluene
(1) Diluting the concentrated sulfuric acid with the mass percent concentration of 98% into dilute sulfuric acid with the mass percent concentration of 75% -85%.
(2) Adding 98% of concentrated nitric acid into the dilute sulfuric acid solution in the step (1) to prepare the aqueous solution.
The molar ratio of the nitric acid to the sulfuric acid solution, namely the mixed acid solution, is 0.5-1.
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1.9-2.4): 1, the temperature of a material conveying pipe is controlled to be 40-60 ℃ in a water bath, stirring reaction is carried out in a tubular reactor, the reaction temperature is controlled to be 40-100 ℃, and the stirring rotation speed is 200-350rad/min, so that a reactant solution is obtained.
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and washing and drying the organic phase to obtain the dinitrotoluene.
A production method and a production device of micro-mixed tube reaction nitrified toluene, wherein the production device comprises the following steps:
A. b and H are storage bottles respectively, C is fluid conveying equipment, specifically a horizontal pump, D is a constant-temperature water bath, E is a micromixer, F is a tubular reactor, and G is a temperature sensor.
According to the material setting proportion, materials are simultaneously conveyed into a micromixer E for premixing through a constant-temperature water bath kettle D from a storage bottle A and a storage bottle B through a fluid conveying device C after temperature control, the materials comprise mixed acid and toluene and react in a tubular reactor F, the tubular reactor F adjusts stirring rotation speed, the temperature of the tubular reactor is controlled through jacket cooling water or the outside of the tubular reactor is kept warm through a heat insulation material to achieve the heat insulation effect, the tubular reactor is connected with a temperature sensor G for displaying the temperature in a segmented mode, reaction liquid after the reaction is stored in the storage bottle H, liquid separation treatment is carried out after the reaction liquid is cooled to room temperature, and an organic phase is a product.
Specifically, as shown in fig. 2, the micro-mixer is a T-type micro-mixer, and includes a micro-channel plate 100, three micro-channels located on the micro-channel plate 100, namely two inlet channels 200 and one mixing channel 400 respectively connected with the inlet channels 200, the inlet channels 200 are respectively connected with two inlet ends 300, the mixing channel 400 is connected with an outlet end 500, the two inlet channels 200 are respectively located at two sides of the micro-channel plate 100, the residence time of the reaction materials in the micro-mixer is extremely short, and the mixing effect of toluene and mixed acid is enhanced.
Specifically, as shown in fig. 3, fig. 4, fig. 5 and fig. 6, the tubular reactor comprises a jacket tube 1, both ends of the jacket tube 1 are respectively provided with a plurality of mounting holes 2, a cavity 3 is arranged in the jacket tube 1, the cavity 3 is communicated with two medium inlet and outlet valve bodies 5, two valve tubes 4 are clamped outside the jacket tube 1, the valve tubes 4 penetrate through the cavity 3, a mixing component 6 is arranged in the jacket tube 1, six heat conducting components 7 are arranged outside the mixing component 6, the six heat conducting components 7 are clamped on a heat conducting inner container 8, the heat conducting inner container 8 is clamped in the jacket tube 1, the mixing component 6 comprises two supports 601, the supports 601 are fixed with the inside of the jacket tube 1, one stirring paddle 602 is arranged between the two supports 601, two stirring paddles 603 are arranged outside the stirring paddle 602, three paddles 604 are arranged outside the stirring paddle 603, the stirring direction is clockwise, the pushing type 604 drives reaction liquid to mix forwards, the three paddles are 120-degree circular, the heat conducting component 7 comprises heat conducting pipes 701, the heat conducting pipes 701 are clamped on the heat conducting inner container 8, the heat conducting pipe 701 is provided with a plurality of heat conducting pieces 703, and the heat conducting pieces are communicated with the cavity 3 through four heat conducting pieces.
The working principle of the tubular reactor is as follows:
when the device is used, the medium inlet and outlet valve body 5 above the jacket pipe 1 is opened, the medium is injected into the cavity 3 through the medium inlet and outlet valve body 5, the medium can enter the heat conducting pipe 701 through the plurality of through pipes 702 after entering the cavity 3, the stirring paddles 602 on the support 601 drive the stirring wings 603 and the paddles 604 to rotate, the reaction liquid in the jacket pipe 1 is stirred, the heat conducting pipe 701 is in a convex shape, the movement direction of the reaction liquid is changed to enable the reaction liquid to be concentrated at the middle part in the jacket pipe 1, and the reaction liquid is driven to mix and flow rightwards.
The heat conduction area is increased by the plurality of heat conduction fins 703 arranged in the heat conduction pipe 701, so that the heat and cold transfer rate is improved, the reaction effect is improved, and the uniformity of heat and cold transfer is improved by matching with the arrangement of the heat conduction liner 8.
The heat transfer pipe 701 is protruded, and the movement direction of the reaction liquid is changed to be concentrated at the inner middle part of the jacket pipe 1, so that even if the fluid flux is increased, a good mixing effect can be ensured.
Example 1:
(1) 714.29g of concentrated sulfuric acid with the mass percent concentration of 98% is slowly added into 285.71g of water to prepare 1000 g of dilute sulfuric acid with the mass percent concentration of 70%;
(2) Adding 136.76g of concentrated nitric acid with the mass percent concentration of 98% into the dilute sulfuric acid solution with the mass percent concentration of 70% in the step (1), preparing a sulfuric acid solution (mixed acid solution) of nitric acid, wherein the molar ratio of nitric acid to sulfuric acid is 0.3, and adding the mixed acid solution into a storage bottle A;
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be 1.02:1, controlling the temperature of a material conveying pipe in a water bath to be 30 ℃, and stirring the material conveying pipe in a tubular reactor at normal temperature for reaction, wherein the stirring speed is 250rad/min to obtain a reactant solution;
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, sampling the organic phase, washing the organic phase with water to be neutral, and then performing gas chromatographic analysis.
The gas chromatography detection result of the mononitrotoluene prepared in the embodiment is as follows: toluene (0.5%), ortho-nitrotoluene (59.16%), meta-nitrotoluene (3.94%), para-nitrotoluene (35.5%), dinitrotoluene (0.8%), and from this result, it can be seen that in this example, toluene conversion is greater than 99%, mononitrotoluene purity is greater than 98.5%, and dinitrotoluene by-product is less than 1%.
Example 2:
(1) 755.10g of concentrated sulfuric acid with the mass percent concentration of 98% is slowly added into 244.90g of water to prepare 1000 g of dilute sulfuric acid with the mass percent concentration of 74%;
(2) Adding 194.17g of concentrated nitric acid with the mass percent concentration of 98% into the dilute sulfuric acid solution with the mass percent concentration of 74% in the step (1), preparing a sulfuric acid solution (mixed acid solution) of nitric acid, wherein the molar ratio of nitric acid to sulfuric acid is 0.3, and adding the mixed acid solution into a storage bottle A;
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be 1:1, controlling the temperature of a material conveying pipe in a water bath to be 40 ℃, stirring and reacting in a tubular reactor, preserving heat of the reactor by using a heat preservation material, and stirring at a rotating speed of 250rad/min to obtain a reactant solution;
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, sampling the organic phase, washing the organic phase with water to be neutral, and then performing gas chromatographic analysis.
The gas chromatography detection result of the mononitrotoluene prepared in the embodiment is as follows: toluene (0.1%), ortho-nitrotoluene (58.80%), meta-nitrotoluene (3.92%), para-nitrotoluene (35.28%), dinitrotoluene (1.40%).
Example 3:
(1) 816.33g of concentrated sulfuric acid with the mass percent concentration of 98% is slowly added into 183.67g of water to prepare 1000 g of dilute sulfuric acid with the mass percent concentration of 80%;
(2) Adding 419.83g of concentrated nitric acid with the mass percent concentration of 98% into the dilute sulfuric acid solution with the mass percent concentration of 74% in the step (1), preparing a sulfuric acid solution (mixed acid solution) of nitric acid, wherein the molar ratio of nitric acid to sulfuric acid is 0.8, and adding the mixed acid solution into a storage bottle A;
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be 2.1:1, controlling the temperature of a material conveying pipe in a water bath to be 50 ℃, stirring and reacting in a tubular reactor, controlling the temperature to be 80 ℃, and stirring at a rotating speed of 250rad/min to obtain a reactant solution;
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, sampling the organic phase, washing the organic phase with water to be neutral, and then performing gas chromatographic analysis.
The gas chromatography detection result of the mononitrotoluene prepared in the embodiment is as follows: toluene (0.1%), ortho-nitrotoluene (0.42%), meta-nitrotoluene (0.25%), para-nitrotoluene (0.03%), 2,4-DNT (79.95%), 2,6-DNT (18.75%).
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
While the preferred embodiments of the present patent have been described in detail, the present patent is not limited to the above embodiments, and various changes may be made without departing from the spirit of the present patent within the knowledge of one of ordinary skill in the art.

Claims (7)

1. The production method and the production device of the micro-mixed tube reaction nitrified toluene are characterized by comprising the following steps:
a) Preparation of mononitrotoluene
(1) Diluting 98% by mass of concentrated sulfuric acid into 65% -75% by mass of dilute sulfuric acid;
(2) Adding 98% by mass of concentrated nitric acid into the dilute sulfuric acid solution obtained in the step (1) to prepare the aqueous solution;
sulfuric acid solution of nitric acid, namely mixed acid solution, wherein the molar ratio of nitric acid to sulfuric acid is 0.1-0.5;
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1-1.1): 1, controlling the temperature of a material conveying pipe in a water bath to be 30-50 ℃;
stirring reaction is carried out in a tubular reactor, the reaction temperature is controlled to be 40-100 ℃, and the stirring rotation speed is 200-350rad/min, so as to obtain a reactant solution;
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and performing alkali washing and water washing on the organic phase until the organic phase is neutral to obtain mononitrotoluene;
when the DNT concentration in the product is allowed to exceed 1%, the tubular reactor adopts heat insulation, the heat generated by the reaction is fully utilized, the reaction temperature reaches 90-100 ℃, the energy is saved, the reaction efficiency is improved, the dilute sulfuric acid concentration is optimally controlled to 73-75%, and the molar ratio of nitric acid to toluene is optimally controlled to be (1.05-1.1): 1.
when the DNT concentration in the product is allowed to be not more than 1%, the tubular reactor adopts temperature control, the reaction temperature is controlled to be 40-50 ℃, the dilute sulfuric acid concentration is optimally controlled to be 71-73%, and the molar ratio of nitric acid to toluene is (1.02-1.05): 1, controlling the reaction intensity in this way, and ensuring that MNT is not excessively nitrified into DNT in the later stage of the reaction;
b) Preparation of dinitrotoluene
(1) Diluting 98% by mass of concentrated sulfuric acid into 75% -85% by mass of dilute sulfuric acid;
(2) Adding 98% by mass of concentrated nitric acid into the dilute sulfuric acid solution obtained in the step (1) to prepare the aqueous solution;
sulfuric acid solution of nitric acid, namely mixed acid solution, wherein the molar ratio of nitric acid to sulfuric acid is 0.5-1;
(3) The two material flows of the mixed acid of the reactant and the toluene are synchronously pumped into two inlets of the micromixer through a metering pump, and the molar ratio of the nitric acid to the toluene is controlled to be (1.9-2.4): 1, controlling the temperature of a material conveying pipe in a water bath to be 40-60 ℃, stirring and reacting in a tubular reactor, controlling the reaction temperature to be 40-100 ℃ and the stirring rotation speed to be 200-350rad/min to obtain a reactant solution;
(4) Cooling the reactant solution in the step (3) to normal temperature, separating the reactant solution to obtain an organic phase and an acid phase, and washing and drying the organic phase to obtain the dinitrotoluene.
2. The production method and production device of micro-mixed tube reaction nitrified toluene according to claim 1, wherein the production device comprises:
A. b and H are storage bottles respectively, C is fluid conveying equipment, specifically a horizontal pump, D is a constant-temperature water bath, E is a micromixer, F is a tubular reactor, and G is a temperature sensor;
according to the material setting proportion, materials are simultaneously conveyed into a micromixer E for premixing through a constant-temperature water bath kettle D from a storage bottle A and a storage bottle B through a fluid conveying device C after temperature control, the materials comprise mixed acid and toluene and react in a tubular reactor F, the tubular reactor F adjusts stirring rotation speed, the temperature of the tubular reactor is controlled through jacket cooling water or the outside of the tubular reactor is kept warm through a heat insulation material to achieve the heat insulation effect, the tubular reactor is connected with a temperature sensor G for displaying the temperature in a segmented mode, reaction liquid after the reaction is stored in the storage bottle H, liquid separation treatment is carried out after the reaction liquid is cooled to room temperature, and an organic phase is a product.
3. The production method and the production device of the micro-mixed tube reaction nitrified toluene according to claim 2, which are characterized in that: the micro-mixer is specifically a T-shaped micro-mixer and comprises a micro-channel plate (100), three micro-channels are arranged on the micro-channel plate (100), namely two inlet channels (200) and one mixing channel (400) connected with the inlet channels (200) respectively, the inlet channels (200) are connected with two inlet ends (300) respectively, the mixing channel (400) is connected with an outlet end (500), the two inlet channels (200) are respectively arranged on two sides of the micro-channel plate (100), the residence time of reaction materials in the micro-mixer is extremely short, and the mixing effect of toluene and mixed acid is enhanced.
4. The production method and the production device of the micro-mixed tube reaction nitrified toluene according to claim 2, which are characterized in that: the tubular reactor comprises a jacket pipe (1), a plurality of mounting holes (2) are formed in two ends of the jacket pipe (1), a cavity (3) is formed in the jacket pipe (1), the cavity (3) is communicated with two medium inlet and outlet valve bodies (5), two valve pipes (4) are clamped outside the jacket pipe (1), the valve pipes (4) penetrate through the cavity (3), a mixing assembly (6) is arranged in the jacket pipe (1), six heat conducting assemblies (7) are arranged outside the mixing assembly (6), the six heat conducting assemblies (7) are clamped on a heat conducting liner (8), and the heat conducting liner (8) is clamped in the jacket pipe (1).
5. The production method and the production device of the micro-mixed tube reaction nitrified toluene, which are characterized in that: the mixing assembly (6) comprises two brackets (601), the brackets (601) are fixed with the inner phase of the jacket pipe (1), the same stirring paddle (602) is arranged between the two brackets (601), two stirring wings (603) are arranged outside the stirring paddle (602), and three paddles (604) are arranged outside the stirring wings (603).
6. The production method and the production device of the micro-mixed tube reaction nitrified toluene, which are characterized in that: the stirring direction of the paddles (604) is clockwise and downward, the reaction liquid is driven to be mixed and advance, and the three paddles (604) form a 120-degree circular row for one circle.
7. The production method and the production device of the micro-mixed tube reaction nitrified toluene, which are characterized in that: the heat conduction assembly (7) comprises a heat conduction pipe (701), the heat conduction pipe (701) is clamped on the heat conduction liner (8), a plurality of heat conduction sheets (703) are arranged in the heat conduction pipe (701), and the heat conduction pipe (701) is communicated with the cavity (3) through four through pipes (702).
CN202211094180.5A 2022-09-08 2022-09-08 Production method and production device of micro-mixed tube type reaction nitrified toluene Pending CN116272769A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116571189A (en) * 2023-07-07 2023-08-11 江苏长青农化南通有限公司 Preparation process of 5- (2-chloro-4- (trifluoromethyl) phenoxy) -2-nitrobenzoic acid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116571189A (en) * 2023-07-07 2023-08-11 江苏长青农化南通有限公司 Preparation process of 5- (2-chloro-4- (trifluoromethyl) phenoxy) -2-nitrobenzoic acid
CN116571189B (en) * 2023-07-07 2024-04-02 江苏长青农化南通有限公司 Preparation process of 5- (2-chloro-4- (trifluoromethyl) phenoxy) -2-nitrobenzoic acid

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