CN117282375A - System and method for continuously preparing 80/20DNT by utilizing microreactor - Google Patents
System and method for continuously preparing 80/20DNT by utilizing microreactor Download PDFInfo
- Publication number
- CN117282375A CN117282375A CN202311242742.0A CN202311242742A CN117282375A CN 117282375 A CN117282375 A CN 117282375A CN 202311242742 A CN202311242742 A CN 202311242742A CN 117282375 A CN117282375 A CN 117282375A
- Authority
- CN
- China
- Prior art keywords
- reactor
- micro
- toluene
- stage
- dnt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 81
- 238000006243 chemical reaction Methods 0.000 claims abstract description 44
- 239000002253 acid Substances 0.000 claims abstract description 27
- DYSXLQBUUOPLBB-UHFFFAOYSA-N 2,3-dinitrotoluene Chemical compound CC1=CC=CC([N+]([O-])=O)=C1[N+]([O-])=O DYSXLQBUUOPLBB-UHFFFAOYSA-N 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 238000005406 washing Methods 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 13
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 11
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 11
- 239000000945 filler Substances 0.000 claims description 11
- 229910017604 nitric acid Inorganic materials 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 5
- 239000010935 stainless steel Substances 0.000 claims description 5
- 229910000856 hastalloy Inorganic materials 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 3
- RMBFBMJGBANMMK-UHFFFAOYSA-N 2,4-dinitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1[N+]([O-])=O RMBFBMJGBANMMK-UHFFFAOYSA-N 0.000 abstract description 12
- 238000002360 preparation method Methods 0.000 abstract description 10
- 239000002994 raw material Substances 0.000 abstract description 10
- XTRDKALNCIHHNI-UHFFFAOYSA-N 2,6-dinitrotoluene Chemical compound CC1=C([N+]([O-])=O)C=CC=C1[N+]([O-])=O XTRDKALNCIHHNI-UHFFFAOYSA-N 0.000 abstract description 9
- ZPTVNYMJQHSSEA-UHFFFAOYSA-N 4-nitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1 ZPTVNYMJQHSSEA-UHFFFAOYSA-N 0.000 abstract description 6
- 238000006396 nitration reaction Methods 0.000 abstract description 6
- 239000007788 liquid Substances 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 description 10
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 9
- 239000012071 phase Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 238000012546 transfer Methods 0.000 description 8
- 239000012074 organic phase Substances 0.000 description 5
- 239000000376 reactant Substances 0.000 description 5
- 239000012948 isocyanate Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 3
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- -1 aliphatic isocyanate Chemical class 0.000 description 3
- 239000012295 chemical reaction liquid Substances 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical class [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920001451 polypropylene glycol Polymers 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 230000036632 reaction speed Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000007806 chemical reaction intermediate Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000005182 dinitrobenzenes Chemical class 0.000 description 1
- VMMLSJNPNVTYMN-UHFFFAOYSA-N dinitromethylbenzene Chemical group [O-][N+](=O)C([N+]([O-])=O)C1=CC=CC=C1 VMMLSJNPNVTYMN-UHFFFAOYSA-N 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- 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
- B01J19/0046—Sequential or parallel reactions, e.g. for the synthesis of polypeptides or polynucleotides; Apparatus and devices for combinatorial chemistry or for making molecular arrays
-
- 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
- B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
-
- 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
- B01J19/24—Stationary reactors without moving elements inside
- B01J19/2415—Tubular reactors
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention belongs to the technical field of micro-chemical industry, and particularly relates to a system and a method for continuously preparing 80/20DNT from toluene. The nitration reaction of toluene and mixed acid belongs to liquid-liquid heterogeneous strong exothermic reaction. The system and the method for combining the multichannel microreactor and the tubular reactor realize continuous preparation of dinitrotoluene by direct nitration of toluene, and have the advantages of high raw material conversion rate, product compliance with 80/20 standards of enterprises, process safety and the like. Toluene and Mononitrotoluene (MNT) conversion is above 99.9%, dinitrotoluene (DNT) yields are above 99%, wherein the percentages of 2,4-DNT and 2,6-DNT are above 96%, 2,4-DNT/2, 6-dnt=3.76-4.26.
Description
Technical Field
The invention belongs to the technical field of micro-chemical industry, relates to a continuous preparation process of dinitrobenzene compounds, and in particular relates to a system and a method for continuously preparing 80/20DNT products from toluene.
Background
Dinitrotoluene is an important raw material for the polyurethane industry, and polyurethane main raw materials including diphenylmethane diisocyanate (MDI), toluene Diisocyanate (TDI) and polypropylene glycol (PPG) are currently becoming internationalized. The production technology and equipment of the raw materials are complex, and the product competition is quite strong. DNT is mainly used for the preparation of Toluene Diisocyanate (TDI). Isocyanates are a generic term for various esters of isocyanic acid. Can be divided into aliphatic isocyanate and aromatic isocyanate, and the use amount of the aromatic isocyanate is the largest at present, such as MDI, TDI and the like.
Since two nitro groups in the dinitrotoluene structure are different in positions on the benzene ring, three types of TDI are produced, namely TDI-100, TDI-80 and TDI-65, wherein TDI-80 is prepared from 80% of 2,4-DNT and 20% of 2,6-DNT, and the market demand of TDI-80 is huge. The 2,4-DNT content of 80% and the 2,6-DNT content of 20% are commonly known in the dinitrotoluene production industry as 80/20DNT.
The chemical reaction carried out in a conventional kettle type is that a certain active group of a reactant molecule indiscriminately attacks other parts in the molecule or any part of another molecule, and the selectivity of the reaction is determined by the reactivity and steric hindrance of the attacked part in the molecule. In microreaction, reactants have certain orientation and ordered arrangement at molecular level, and at the same time, the microreactor limits the movement of reactant molecules and reaction intermediates, and the orientation, arrangement and limiting effect influence and determine the direction (i.e. the selectivity of the product) and the speed of the reaction, so that the research on the finite field effect in the microreactor is more and more important in the aspect of the product selectivity.
Dinitrotoluene (DNT) is the product of the two-stage nitration of toluene in a mixed acid, which is a heterogeneous, strongly exothermic reaction. In the prior art, 80/20DNT production is realized by adopting a kettle type two-stage nitration process. The method has the problems of long reaction period, low process safety, poor product selectivity and the like. Compared with the conventional kettle type production, the micro-reactor has the advantages of high mass transfer coefficient, improved reaction speed and greatly shortened reaction period. Secondly, the microreactor has less online materials and safe and controllable process. More importantly, the micro-reaction has larger specific surface area, larger heat exchange efficiency, orientation, arrangement and confinement effect on reactant molecules, and improves the selectivity of the product. Therefore, a novel efficient continuous preparation system and method meeting the requirements of 80/20 products of enterprises are a problem to be solved.
Disclosure of Invention
In order to solve the problems of poor product selectivity, complicated working procedures, long reaction period, safety caused by large heat release amount in the reaction process and the like in the existing kettle type production process. Aiming at the characteristics of a kettle-type dinitrotoluene preparation process, the invention provides a system and a method for continuously preparing 80/20DNT by using toluene by using a microreactor, and the mass transfer and heat transfer capabilities of the reaction process can be enhanced by using the mass transfer and heat transfer efficiency and the finite field effect of the microreactor, so that the product selectivity and the process safety are improved. The conversion rate of toluene and Mononitrotoluene (MNT) is more than 99.9%, the yield of dinitrotoluene reaches more than 99%, wherein the percentages of 2,4-DNT and 2,6-DNT are more than 96%, and the 2,4-DNT/2,6-DNT completely accords with 80/20 product standards of enterprises.
The technical scheme adopted by the invention is as follows:
in one aspect, the invention provides a micro-reaction system for continuously preparing 80/20DNT by using toluene through a micro-reactor, which comprises a first-stage micro-reactor and a second-stage micro-reactor, wherein the first-stage micro-reactor is a multi-channel micro-mixing reactor, the first-stage micro-reactor is provided with a micro-heat exchanger, the second-stage micro-reactor is provided with heat exchange equipment and filler, the temperatures of the first-stage micro-reactor and the second-stage micro-reactor are controlled through the micro-heat exchanger and the heat exchange equipment, and the first-stage multi-channel micro-reactor, the second-stage micro-reactor and a sequential collecting kettle are sequentially connected in series.
Based on the technical scheme, the micro heat exchanger and the heat exchange equipment are external refrigerant circulation equipment.
Based on the technical scheme, further, the multichannel microreactor is internally provided with a micro heat exchanger, the micro heat exchanger is a fin type heat exchanger, the channel width is 1-2 mm, and the hydraulic diameter is 0.1-3 mm.
Based on the technical scheme, further, the second-stage reactor is a filler pipe type reactor, the second-stage reactor is provided with a heat exchange sleeve, the pipe type reactor is a pipe body with the pipe diameter of 6.0mm (diameter) multiplied by 1.0mm (thickness) and the length of 100-800 mm, and triangular spiral filler is arranged in the pipe body.
Based on the technical scheme, further, the pipe body is made of stainless steel (such as 316 and 316L) or hastelloy, the filler is triangular spiral stainless steel (such as 316 and 316L) or hastelloy, and the triangular spiral filler is 1.0-3.0 mm multiplied by 1.0-3.0 mm in size.
Based on above technical scheme, collect cauldron including stirred tank, separation cauldron of standing, washing alkaline washing cauldron, stirred tank, separation cauldron of standing, washing alkaline washing cauldron connect gradually.
In another aspect, the present invention provides a method for continuously preparing 80/20DNT from toluene using a microreactor, using the above-described microreaction system, comprising the steps of: at the reaction temperature, toluene and mixed acid are mixed in a multi-channel reactor and a tubular reactor and react, heat released by the reaction is removed through heat exchange in time through the reactor, materials are mixed and reacted completely through the multi-channel reactor and the tubular reactor, and then enter a collecting kettle, and the dinitrotoluene product is obtained through separation, water washing and alkali washing; wherein the mixed acid is a mixed acid solution of nitric acid and sulfuric acid.
Based on the technical scheme, further, the molar ratio of the nitrate to the sulfur (nitric acid and sulfuric acid) in the mixed acid solution is 1:2-4, wherein the water content is 2wt.% to 15wt.%, and the water content of the mixed acid is preferably 14wt.%.
Based on the technical scheme, toluene and mixed acid are mixed and reacted in a reactor, the molar ratio of toluene to nitric acid is 1:2.10-2.25, and the molar ratio of toluene to nitric acid is 1:2.17-2.22.
Based on the technical scheme, further, the reaction temperature of the multichannel micro-reactor and the tubular reactor is controlled to be 60-100 ℃, and the reaction temperature is preferably 75 ℃.
Based on the above technical scheme, further, the total residence time of the materials in the reactors (the multi-channel reactors and the tubular reactors) is 1-5 minutes, and the preferable residence time is 4.7 minutes.
Based on the technical scheme, the method for continuously preparing 80/20DNT by utilizing the microreactor comprises the following steps:
(1) Preparing a mixed acid solution, namely preparing the mixed acid solution required by a test at room temperature, wherein the molar ratio of the nitrate to the sulfur is 1:2-4, and the water content is 2-15 wt%;
(2) The two materials are input into a reactor through two continuous conveying devices, mixed and reacted in the reactor, the temperatures of the multichannel micro-reactor and the tubular reactor are controlled through a heat exchanger, and after the raw materials are completely converted, the reaction liquid flows into a collecting kettle.
(3) And standing the materials in a collecting kettle to separate an acid phase, and washing an organic phase with water and alkali to obtain the dinitrotoluene product.
The nitration reaction of toluene and mixed acid belongs to liquid-liquid heterogeneous strong exothermic reaction. The system and the method for combining the multichannel microreactor and the tubular reactor realize continuous preparation of dinitrotoluene by direct nitration of toluene, and have the advantages of high raw material conversion rate, product compliance with 80/20 standards of enterprises, process safety and the like. Toluene and Mononitrotoluene (MNT) conversion is above 99.9%, dinitrotoluene (DNT) yields are above 99%, wherein the percentages of 2,4-DNT and 2,6-DNT are above 96%, 2,4-DNT/2, 6-dnt=3.76-4.26.
The beneficial effects of the invention are as follows:
(1) Realizing the continuous preparation of 80/20DNT in the microreactor;
(2) Compared with the kettle type preparation of 80/20DNT, the method has the advantages that the multichannel micro-reactor and the tubular reactor are combined, so that 80/20DNT is continuously prepared, and the raw material conversion rate is high, the product yield is high, the process is stable and the like through optimizing equipment and process conditions;
(3) The micro-reactor system has the advantages of high mass transfer coefficient, improved reaction speed and greatly shortened reaction period;
(4) The micro-reactor system and the method shorten the residence time of the reaction liquid in the reactor, avoid other side reactions and improve the reaction selectivity;
(5) The production process has less on-line materials and high safety.
(6) The micro-reactor system has the advantages of large specific surface area, large heat exchange efficiency, orientation, arrangement and domain limiting effect on reactant molecules, product selectivity improvement, and complete compliance of the product with the 80/20DNT standard of enterprises.
The characteristic advantages of the invention will be apparent from the following description of the examples of embodiment.
Drawings
FIG. 1 is a flow chart of a process for the continuous preparation of dinitrotoluene according to the invention.
Detailed Description
The invention will be further illustrated by the following examples, which are not intended to limit the scope of the invention, in order to provide a better understanding of the invention to those skilled in the art. The reagents used in the examples are all commercially available, and the technical means used in the examples are conventional means known to those skilled in the art.
Toluene flow, mixed acid flow, mole ratio of nitrate to sulfur, mole ratio of nitric acid to toluene, water content of mixed acid, reaction temperature and residence time are respectively calculated by Q org 、Q aq 、N/S、N/T、T, t.
Example 1 microreactor the specific procedure for the continuous preparation of 80/20DNT is as follows:
as shown in FIG. 1, the micro-reaction system for continuously preparing 80/20DNT by using toluene comprises a first-stage micro-reactor and a second-stage micro-reactor, wherein the first-stage multi-channel micro-reactor, the second-stage micro-reactor and a collecting kettle are sequentially connected in series, the collecting kettle comprises a stirring kettle, a static separation kettle and a water-washing alkali-washing kettle, and the stirring kettle, the static separation kettle and the water-washing alkali-washing kettle are sequentially connected. The first stage micro-reactor is sixteen-channel micro-mixing reactor, built-in fin type micro-heat exchanger, the channel width is 1.5mm, and the hydraulic diameter is 0.3mm. The second diode type reactor is a filler pipe type reactor, the second diode type reactor is provided with a heat exchange sleeve, the pipe type reactor is a stainless steel pipe with the pipe diameter of 6.0mm (diameter) multiplied by 1.0mm (thickness) and the length of 700mm, and a triangular spiral filler with the pipe diameter of 3.0mm multiplied by 3.0mm is arranged in the pipe type reactor, and the effective volume is 5mL.
(1) 64.78g of water was first added to a 500ml flask, concentrated sulfuric acid (4.0 mol,400 g) was slowly added to the flask, cooled with cold water, fuming nitric acid (1.00 mol,64.3 g) was slowly added to the flask after the sulfuric acid addition was completed, and stirred uniformly to form a transparent mixed acid solution, the mass concentration of nitric acid was 11.91wt.%, the mass concentration of water was 14wt.%, and toluene was used as the raw material phase B and toluene as the phase a.
(2) Two feed phases A (Q) org =3.5 ml/min) and B (Q aq =28.5 ml/min) was fed into the multichannel reactor by two advection pumps, the two materials were thoroughly mixed and reacted in the multichannel microreactor; the reaction materials are further mixed and reacted in the packed tubular reactor, the total residence time is 4.7min, and the materials flow out of the reactor to enter a collecting kettle after being completely converted. Meanwhile, the reaction temperature of the multichannel micro-reactor and the packing tube reactor is controlled to be 75 ℃, and the temperature of the collecting kettle is controlled to be 65 ℃. The reaction liquid enters a collecting kettle to stand for separating a lower acid phase, hot water (75 ℃) is added, stirring is carried out to wash the residual acid in the organic phase, an acid water phase is separated, saturated sodium bicarbonate solution is continuously added, the organic phase is washed, and the water phase is separated to obtain the dinitrotoluene product, the conversion rate of raw materials is 99.9%, the yield of the dinitrotoluene product is 99.5%, the percentages of 2,4-DNT and 2,6-DNT are above 96.4%, and 2,4-DNT/2, 6-DNT=4.25.
Examples 2-8 the microreactor continuously produces dinitrotoluene as follows:
a system for continuously preparing 80/20DNT was used as in example 1. In the reaction process, the reaction temperature is 75 ℃, and specific results are shown in Table 1 respectively.
TABLE 1 influence of mixed acids of different water contents on dinitrotoluene yield and 2,4-DNT/2,6-DNT
Examples 9-12 microreactors continuously produce dinitrotoluene stability tests, comprising the following steps:
a system for continuously preparing 80/20DNT was used as in example 1. Under the optimal process conditions, Q org ＝3.5ml/min,Q aq ＝28.5ml/min，N/S＝1:4，N/T＝2.22，t=4.7 min. Controlling the reaction temperature of the multichannel reactor and the tubular reactor to be 75 ℃, mixing and reacting reaction materials in the microreactor, standing the reaction solution in a collecting kettle after the reaction is completed to separate a lower acid phase, adding hot water (75 ℃) to stir and wash residual acid in an organic phase, separating an acid aqueous phase, continuously adding saturated sodium bicarbonate solution, washing the organic phase, and separating the aqueous phase to obtain the product dinitrotoluene. The specific results are shown in Table 2.
TABLE 2 influence of different sample injection amounts on DNT yield, stability of 2,4-DNT/2,6-DNT
The system for continuously preparing 80/20DNT by combining the multichannel microreactor and the tubular reactor effectively improves the problems of poor selectivity of the materials in kettle type production, long reaction period and production safety caused by exothermic reaction in the production process by utilizing the characteristics of efficient mass transfer and heat transfer and the finite field effect of the multichannel microreactor and the effect of enhancing the mixing of the tubular reactor, and improves the raw material conversion rate, the product selectivity and the production safety.
Those skilled in the art will appreciate that certain modifications and adaptations of the invention may be made. Such modifications and adaptations are intended to be within the scope of the present invention as defined in the appended claims.
Claims (9)
1. The micro-reaction system for continuously preparing 80/20DNT by using toluene is characterized by comprising a first-stage micro-reactor and a second-stage micro-reactor, wherein the first-stage micro-reactor is a multi-channel micro-mixing reactor, the first-stage micro-reactor is provided with a micro heat exchanger, the second-stage micro-reactor is provided with heat exchange equipment and filler, the temperature of the first-stage micro-reactor and the temperature of the second-stage micro-reactor are controlled by the micro heat exchanger and the heat exchange equipment, and the first-stage micro-reactor, the second-stage micro-reactor and a collecting kettle are sequentially connected in series.
2. The micro-reaction system of claim 1, wherein the micro-channels of the multi-channel mixing reactor have a hydraulic diameter of 0.1-3 mm.
3. The micro-reaction system according to claim 1, wherein the second-stage reactor is a tube body with an outer diameter of 6.0mm, a thickness of 1.0mm and a length of 100-800 cm, and is internally provided with a triangular spiral filler.
4. The microreaction system according to claim 1, wherein the tube body is a stainless steel tube or hastelloy tube, and the filler is a delta spiral stainless steel or hastelloy filler.
5. A method for continuously preparing 80/20DNT by using toluene by using a microreactor, which uses the microreaction system as claimed in any one of claims 1-4, and is characterized in that toluene and mixed acid are mixed and reacted in a multi-channel reactor and a tubular reactor at the reaction temperature, materials are mixed and reacted completely in the multi-channel reactor and the tubular reactor, and then enter a collecting kettle, and the products of dinitrotoluene are obtained through separation, water washing and alkali washing; wherein the mixed acid is a mixed acid solution of nitric acid and sulfuric acid.
6. The process according to claim 5, wherein the reaction temperature of the multichannel microreactor and the tubular reactor is controlled between 60 ℃ and 100 ℃, preferably 75 ℃.
7. The method according to claim 5, wherein the molar ratio of nitric acid to sulfuric acid in the mixed acid is 1:2-4, the water content is 2-15 wt.%, preferably the water content of the mixed acid is 14wt.%.
8. The process according to claim 5, wherein the molar ratio of toluene to nitric acid is 1:2.10-2.25, preferably the molar ratio of toluene to nitric acid is 1:2.17-2.22.
9. The process according to claim 5, wherein the total residence time of the material in the reactor is 1 to 5min, preferably 4.7min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311242742.0A CN117282375A (en) | 2023-09-25 | 2023-09-25 | System and method for continuously preparing 80/20DNT by utilizing microreactor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311242742.0A CN117282375A (en) | 2023-09-25 | 2023-09-25 | System and method for continuously preparing 80/20DNT by utilizing microreactor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117282375A true CN117282375A (en) | 2023-12-26 |
Family
ID=89240314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311242742.0A Pending CN117282375A (en) | 2023-09-25 | 2023-09-25 | System and method for continuously preparing 80/20DNT by utilizing microreactor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117282375A (en) |
-
2023
- 2023-09-25 CN CN202311242742.0A patent/CN117282375A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101544567B (en) | Nitration method for synthesizing dinitrotoluene in one step | |
| CN101613285B (en) | Synthetic method and special equipment for nitrobenzene | |
| CN102432471B (en) | Method for undergoing chlorobenzene nitration reaction by using micro-channel reactor | |
| US7763759B2 (en) | Continuous process for the manufacture of nitrobenzene | |
| CN113563197B (en) | Method for preparing 3-nitro-4-chlorotrifluorotoluene by continuous adiabatic nitration and micro-reaction equipment | |
| CN109467508B (en) | Method for synthesizing dinitrotoluene by using microchannel reactor | |
| CN109665963B (en) | Synthetic method of 2, 6-dimethyl nitrobenzene | |
| CN112679358B (en) | Method for continuously preparing 3, 5-dinitrobenzoic acid by using microchannel reactor | |
| TW200819414A (en) | A process for the production of dinitrotoluene | |
| CN103342649B (en) | 3-amino-2,4,6-trinitro-diphenylethylene compounds and preparation method thereof | |
| CN102209703B (en) | Adiabatic process for making mononitrobenzene | |
| CN112358400A (en) | Method for synthesizing acifluorfen by nitration in microreactor | |
| CN102040494A (en) | Method for preparing p-fluorobenzaldehyde | |
| JP4257891B2 (en) | Continuous adiabatic process for producing nitrochlorobenzene | |
| CN115043732A (en) | Preparation method of 2, 4-dinitrochlorobenzene | |
| US9150497B2 (en) | Continuous two step flow synthesis of M-amino acetophenone | |
| CN117282375A (en) | System and method for continuously preparing 80/20DNT by utilizing microreactor | |
| CN112851516A (en) | Method for nitrifying o-xylene by using microchannel reactor | |
| CN115819297B (en) | Preparation method of 2-nitro-4-methylsulfonyl benzoic acid | |
| CN111875503B (en) | Preparation method of 2, 6-dichloro-4-trifluoromethyl aniline | |
| CN102399150B (en) | New method for synthesizing hexanitrobibenzyl | |
| US9327263B2 (en) | Stepwise execution of exothermic reactions with participation of carbocations | |
| CN107353211A (en) | The synthetic method of enamine compound and the synthetic method of aromatic aldehyde compound | |
| CN113372231A (en) | Preparation method of 5-amino-1, 2, 3-benzenetricarboxylic acid | |
| CN107903203B (en) | Synthetic method of 3, 4-dinitrophthalimide |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |