CN117466740A - Continuous flow synthesis method of nitromethane - Google Patents
Continuous flow synthesis method of nitromethane Download PDFInfo
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- CN117466740A CN117466740A CN202211558842.XA CN202211558842A CN117466740A CN 117466740 A CN117466740 A CN 117466740A CN 202211558842 A CN202211558842 A CN 202211558842A CN 117466740 A CN117466740 A CN 117466740A
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- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 238000001308 synthesis method Methods 0.000 title claims abstract description 6
- 238000006243 chemical reaction Methods 0.000 claims abstract description 91
- 238000004821 distillation Methods 0.000 claims abstract description 50
- 238000000034 method Methods 0.000 claims abstract description 42
- 239000000047 product Substances 0.000 claims abstract description 41
- VAYGXNSJCAHWJZ-UHFFFAOYSA-N dimethyl sulfate Chemical compound COS(=O)(=O)OC VAYGXNSJCAHWJZ-UHFFFAOYSA-N 0.000 claims abstract description 35
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 claims abstract description 31
- 239000012043 crude product Substances 0.000 claims abstract description 30
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000002156 mixing Methods 0.000 claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 14
- 239000003054 catalyst Substances 0.000 claims abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 8
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical group [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims description 44
- 235000010288 sodium nitrite Nutrition 0.000 claims description 22
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical group [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 20
- 239000002131 composite material Substances 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 5
- 229910001220 stainless steel Inorganic materials 0.000 claims description 5
- 239000010935 stainless steel Substances 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 4
- 239000002585 base Substances 0.000 claims description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims description 2
- AZFNGPAYDKGCRB-XCPIVNJJSA-M [(1s,2s)-2-amino-1,2-diphenylethyl]-(4-methylphenyl)sulfonylazanide;chlororuthenium(1+);1-methyl-4-propan-2-ylbenzene Chemical compound [Ru+]Cl.CC(C)C1=CC=C(C)C=C1.C1=CC(C)=CC=C1S(=O)(=O)[N-][C@@H](C=1C=CC=CC=1)[C@@H](N)C1=CC=CC=C1 AZFNGPAYDKGCRB-XCPIVNJJSA-M 0.000 claims description 2
- 239000011736 potassium bicarbonate Substances 0.000 claims description 2
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 2
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 2
- 235000011181 potassium carbonates Nutrition 0.000 claims description 2
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 2
- 239000004304 potassium nitrite Substances 0.000 claims description 2
- 235000010289 potassium nitrite Nutrition 0.000 claims description 2
- 235000017550 sodium carbonate Nutrition 0.000 claims description 2
- 239000000758 substrate Substances 0.000 claims 6
- 239000006227 byproduct Substances 0.000 abstract description 9
- 238000005187 foaming Methods 0.000 abstract description 9
- 230000008569 process Effects 0.000 abstract description 8
- 238000011010 flushing procedure Methods 0.000 abstract description 6
- 238000005265 energy consumption Methods 0.000 abstract description 2
- 238000007670 refining Methods 0.000 abstract 1
- 239000002994 raw material Substances 0.000 description 16
- 230000003068 static effect Effects 0.000 description 10
- 239000007788 liquid Substances 0.000 description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000007795 chemical reaction product Substances 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000001944 continuous distillation Methods 0.000 description 5
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 5
- 238000005086 pumping Methods 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- -1 coatings Substances 0.000 description 4
- 238000005580 one pot reaction Methods 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 238000004220 aggregation Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000002518 antifoaming agent Substances 0.000 description 3
- 238000004880 explosion Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000006396 nitration reaction Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000035484 reaction time Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000000575 pesticide Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- JSZOAYXJRCEYSX-UHFFFAOYSA-N 1-nitropropane Chemical compound CCC[N+]([O-])=O JSZOAYXJRCEYSX-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 150000001350 alkyl halides Chemical class 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 208000012839 conversion disease Diseases 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000002816 fuel additive Substances 0.000 description 1
- 239000003254 gasoline additive Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- BLLFVUPNHCTMSV-UHFFFAOYSA-N methyl nitrite Chemical compound CON=O BLLFVUPNHCTMSV-UHFFFAOYSA-N 0.000 description 1
- 238000007069 methylation reaction Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000001546 nitrifying effect Effects 0.000 description 1
- MCSAJNNLRCFZED-UHFFFAOYSA-N nitroethane Chemical compound CC[N+]([O-])=O MCSAJNNLRCFZED-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 239000012038 nucleophile Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- FDRCDNZGSXJAFP-UHFFFAOYSA-M sodium chloroacetate Chemical compound [Na+].[O-]C(=O)CCl FDRCDNZGSXJAFP-UHFFFAOYSA-M 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 230000007847 structural defect Effects 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- 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
- C07C201/10—Preparation of nitro compounds by substitution of functional groups 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a continuous flow synthesis method of nitromethane. The method comprises the steps of mixing dimethyl sulfate, nitrite, a catalyst and water to obtain a mixture, continuously feeding the obtained mixture into a first reactor, and reacting at a first temperature to obtain a first reaction solution; continuously feeding the first reaction liquid into a second reactor, and reacting at a second temperature to obtain a second reaction liquid; continuously feeding the second reaction liquid into a distillation tower to obtain a nitromethane crude product, and rectifying to obtain a nitromethane product; the first reactor and the second reactor are plug flow reactors, and the first temperature is smaller than the second temperature. The method has the advantages of milder reaction conditions, easy control of the reaction process, reduction of the generation of byproducts and energy consumption cost, avoidance of potential safety hazards caused by severe foaming and material flushing in the reaction process, and great improvement of process safety and efficiency by refining and accurately controlling the reaction temperatures of the two reaction stages.
Description
Technical Field
The invention relates to the technical field of flow chemical synthesis, in particular to a continuous flow synthesis method of nitromethane.
Background
Nitromethane is an important organic chemical product and organic synthesis intermediate, has the characteristics of good selectivity, small viscosity, low volatility and the like, is widely used for synthesizing high polymer materials, and can also be used for preparing industries of explosives, rocket fuels, pesticides, gasoline additives, coatings, textiles, foods, paints and the like. Nitromethane is also a liquid explosive with good performance, and can be used as a fuel additive to improve the combustion value of fuel and reduce pollution. The nitromethane can be used as a raw material to synthesize a plurality of important organic chemical products, such as nitroalcohol, and the like, so that the nitromethane is also an important raw material in the industries of medicines, pesticides, dyes and the like. In recent years, the market demand for nitromethane has been increasing.
At present, nitromethane mainly has two synthetic methods, namely a methane gas-phase nitration method and a reaction method of dimethyl sulfate and sodium nitrite. The gas-phase nitrifying process for methane includes spraying diluted nitric acid to gasify, and mixing with preheated methane to maintain a certain proportion of nitric acid, methane and water vapour. The mixed gas enters a pipeline reactor taking molten salt as a heating medium, and is directly nitrified under the conditions of normal pressure and 450-550 ℃. Condensing and absorbing reaction products, distilling the obtained nitromethane aqueous solution to obtain crude nitromethane, washing and rectifying to obtain the finished product. The gas phase nitration method has high reaction temperature, high equipment requirement, low yield and potential safety hazard in higher reaction temperature. The reaction method of dimethyl sulfate and sodium nitrite is that sodium nitrite and dimethyl sulfate are added into a reaction kettle to react, and the reaction product is distilled after condensation, distillation, cooling and layering, thus obtaining the finished product. In addition, sodium nitrite and sodium chloroacetate can be used for reaction, and then the reaction product is heated. Nitrite and haloalkane. Other low-carbon alkanes (ethane and propane) can be directly nitrified by chlorine in industry, but the reaction product is a mixture of nitromethane, nitroethane and nitropropane, and the yield is low and the separation and purification are difficult. The reaction method of dimethyl sulfate and sodium nitrite has the characteristics of easily available raw materials, simple process and lower cost, and is a method commonly adopted in the industry at present. In the concrete implementation, the traditional process is a one-pot reaction of dimethyl sulfate and sodium nitrite, but the temperature of the existing kettle-type reactor is not easy to control, so that the potential safety hazards of flushing and flash explosion are caused by severe foaming in the reaction process, even if a defoaming agent is added, the potential safety hazards are difficult to avoid, in addition, the product and the byproducts cannot be timely discharged due to aggregation in the reaction process, and the product yield and the purity are easy to be reduced.
Disclosure of Invention
The invention provides a continuous flow synthesis method of nitromethane, which solves the problem of serious foaming caused by incapability of timely removing reaction materials, simultaneously reduces side reaction occurrence correspondingly, and improves reaction yield and purity.
Specifically, the method comprises the following steps:
(1) Mixing dimethyl sulfate, nitrite, a catalyst and water to obtain a mixture;
(2) Continuously feeding the mixture obtained in the step (1) into a first reactor, and reacting at a first temperature to obtain a first reaction solution;
(3) Continuously feeding the first reaction liquid into a second reactor, and reacting at a second temperature to obtain a second reaction liquid;
(4) Continuously feeding the second reaction liquid into a distillation tower to obtain a nitromethane crude product, and rectifying to obtain a nitromethane product;
the first reactor and the second reactor are plug flow reactors, and the first temperature is smaller than the second temperature.
In particular, according to the method of the present invention, the feeding in step (1) is performed by adding a material containing water but not containing nitrite to a material containing nitrite but not containing water. The nitrite is dissolved in water to absorb a large amount of heat, so that most of the heat released by the reaction of the nitrite and the dimethyl sulfate is consumed, the control of the reaction temperature is facilitated, and the reaction in the first reactor is mildly carried out.
Specifically, a first raw material and a second raw material are supplied as in the above step (1),
the first raw material comprises dimethyl sulfate, nitrite and a catalyst, and does not comprise water, and the second raw material comprises water and does not comprise nitrite;
or,
the first raw material comprises dimethyl sulfate and nitrite, does not comprise water, and the second raw material comprises water and a catalyst and does not comprise nitrite;
the second raw material is added to the first raw material and mixed.
A plug flow reactor refers to a tubular reactor of the type having a strictly uniform radial velocity profile in the flow reactor without any mixing in the axial direction and a forward flow of material like a piston in the ideal flow regime, this flow being called plug flow and no back mixing in the reactor. The flow in a practical plug flow reactor can be varied to approximate this ideal flow.
According to the method of the invention, the reaction of the first stage is carried out in the first plug flow reactor at low temperature, the first reaction liquid is continuously pumped into the second plug flow reactor for reaction, and the second reaction liquid is continuously pumped into the distillation tower. The method has the advantages that the reaction is fast carried out, the product is fast carried out of the reaction system, the safety problems such as foaming and the like caused by product aggregation are reduced, meanwhile, the reaction balance promotion is greatly promoted, and the yield is greatly improved. The reaction of dimethyl sulfate and nitrite can be considered a methylation reaction, as well as a nitration reaction. Nitrite ions dissociated from nitrite (e.g., sodium nitrite) act as amphiphilic nucleophiles. So for the reaction of nitrite (e.g., sodium nitrite) and dimethyl sulfate to nitromethane, nitromethane is formed when the nitrogen atom of nitrite attacks methyl, and the major byproduct nitrosomethyl ester is formed when the oxygen atom attacks methyl. The reaction temperatures required for dimethyl sulfate to remove two methyl groups are different. Considering that dimethyl sulfate hydrolyzes rapidly at high temperatures, the first methyl group of dimethyl sulfate is easily stripped off, so the first stage needs to be carried out at a lower temperature. However, the second methyl group is difficult to leave, the second stage requires reaction at a higher temperature to produce the product, and the product needs to be carried out of the reaction system as soon as possible, so that formation of gaseous byproducts (alkyl nitrite, nitrogen oxides, carbon dioxide, etc.) can not cause strong foaming of the reaction medium, and even if an antifoaming agent is used, the strong foaming phenomenon is difficult to control.
The invention divides the reaction of nitrite (such as sodium nitrite) and dimethyl sulfate into two stages, refines and precisely controls the reaction temperature of the two stages:
the first stage low temperature main reaction:
(CH 3 ) 2 SO 4 +NaNO 2 →CH 3 SO 4 Na+CH 3 NO 2
the second stage high temperature main reaction:
CH 3 SO 4 Na+NaNO 2 →Na 2 SO 4 +CH 3 NO 2
specifically, according to the method of the invention, the plug flow reactor is a plug flow reactor with a temperature control system and is used for controlling the preheating temperature, the temperature in the reaction process and the heat removal after the reaction;
straight pipes, coil pipes, U-shaped pipes and tubes or any combination pipelines connected in series or in parallel are arranged in the plug flow reactor.
The pipeline is made of a metal pipe, a plastic composite metal pipe or a plastic pipe, and is preferably a metal pipe;
preferably, the metal tube is a galvanized tube, a copper tube or a stainless steel tube;
preferably, the plastic-composite metal pipe is an aluminum-plastic composite pipe;
preferably, the plastic tube is a PVC tube or a PE tube.
In particular, the inner diameter of the pipeline of the plug flow reactor1.0-25.0mm (e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 20, 25 mm), preferably 2-10mm; the length is 0.5-15m (e.g. 0.5, 1.0, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15 m), preferably 0.5-2m.
Specifically, the first temperature is 30-50deg.C (e.g., 30, 35, 40, 45, 50 ℃), preferably 30-35deg.C.
Specifically, the second temperature is 80-100deg.C (e.g., 80, 85, 90, 95, 100deg.C), preferably 90-100deg.C.
The reaction at the first temperature is a low-temperature reaction, dimethyl sulfate is accumulated after the reaction in a conventional reaction kettle, the temperature reaches the second temperature, and the dimethyl sulfate can rapidly react and release heat. The adoption of the plug flow reactor can well solve the problems of material accumulation and rapid imbalance of reaction.
Specifically, the distillation temperature in step (4) is 100-110 ℃ (e.g., 100 ℃, 105 ℃, 110 ℃), and the distillation is atmospheric distillation.
Specifically, the reaction pressure in the first reactor and the second reactor is 0.1-0.2MPa.
Specifically, the nitrite is sodium nitrite or potassium nitrite, especially sodium nitrite.
Specifically, the catalyst is a base or a strong alkali weak acid salt, for example, the base may be sodium hydroxide, potassium hydroxide, and the strong alkali weak acid salt may be sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.
In particular, the molar ratio of dimethyl sulfate to nitrite is in the range 1:2 to 2.2 (e.g., 1:2, 1:2.05, 1:2.1, 1:2.2), particularly 1:2 to 2.1. Molar ratios of dimethyl sulfate to nitrite below or above the selected range can significantly reduce the yield of nitromethane product.
In particular, the mass ratio of catalyst to nitrite is from 0.01 to 0.1:1 (e.g. 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1), in particular from 0.02 to 0.06:1. Too low or too high a catalyst amount may reduce the nitromethane product yield.
Specifically, the mass ratio of water to nitrite in step (1) is 0.1-1:1 (e.g., 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1), especially 0.3-0.6:1. Too little water consumption can not dissolve raw materials well, too much water consumption can excessively dilute raw materials, and can not react well.
In one embodiment of the present invention, the step (4) further includes a step of recovering nitromethane from a column bottom liquid of the distillation column, specifically, for example, the column bottom liquid is collected periodically, and then the distillation column is used for distillation recovery to obtain a nitromethane crude product, and the nitromethane crude product is rectified separately or by combining two nitromethane crude products to obtain a nitromethane product.
The invention also provides the application of the plug flow reactor in synthesizing nitromethane by a dimethyl sulfate substitution method.
Specifically, the dimethyl sulfate substitution method refers to the synthesis of nitromethane by using dimethyl sulfate to undergo substitution reaction with nitrite (such as sodium nitrite) solution.
In particular, the plug flow reactor has the corresponding definition of the invention as described above.
In the reaction process of the plug flow reactor, the materials keep continuous and stable flow along the movement direction, the reaction is uniform, the products are quickly taken out of the reaction system after being generated, are not accumulated in the reactor, the occurrence of side reactions is reduced, and the product yield is improved. The equipment used by the invention has small occupied area, high reaction conversion rate, capability of realizing continuous feeding and discharging, greatly shortening the reaction time, high automation degree, improving the reaction selectivity, improving the product yield and the product purity, controllable online production safety risk and eliminating potential safety hazards.
Advantageous effects
1. The invention adopts a plug flow reactor, compared with a one-pot method, the invention has the advantages of short reaction residence time, more accurate reaction controllable temperature range, safe and reliable process, stable process control and high product yield; the traditional reaction kettle type production process has structural defects due to the limitation of the structure of the reaction kettle, such as small heat exchange area, difficult timely removal of products, uncontrolled reaction temperature and the like. The heat generated in the reaction process cannot be removed in time due to the small heat exchange area of the reaction kettle, the temperature in the reaction kettle is not controlled, and accidents such as kettle flushing and material flushing are easy to occur due to the rise of the temperature in the reaction kettle; the reaction products are not easy to be removed in time, the back mixing generated by the retention of the products in the kettle is easy to generate by-products, the reaction time in the kettle is long, the reaction yield is low, and the product quality is poor. The temperature of the reaction kettle is not easy to control, so that potential safety hazards such as foaming and flushing, flash explosion and the like in the reaction process can be caused, and the problem of foaming and flushing is difficult to avoid even if a defoaming agent is added. Intermittent reaction start-stop is also easy to cause safety accidents.
2. The invention particularly adopts a feeding mode that the material containing water but not containing nitrite is added to the material containing nitrite but not containing water. The nitrite dissolution and heat absorption are beneficial to the control of the exothermic temperature of the reaction, the reaction condition is milder, the reaction process is easy to control, and the generation of byproducts and the energy consumption cost are reduced;
3. according to the invention, a mode of continuously inputting materials into the first plug flow reactor is adopted, the intermediate product is rapidly fed into the second plug flow reactor for reaction, the promotion of the reaction balance of the second stage is promoted, the second reaction liquid is rapidly brought out of the reaction system and then enters the distillation tower, and the product is continuously produced, so that the production of the byproduct methyl nitrite is suppressed while the nitromethane yield of the main product is improved, and the foaming phenomenon is greatly reduced. Compared with a one-pot method, the method also avoids the danger of flash explosion caused by too fast rise of the aggregation temperature of materials in the reaction kettle;
4. the invention divides the reaction of nitrite and dimethyl sulfate into two stages of reactions, refines and precisely controls the reaction temperature of the two stages. The first plug flow reactor and the second plug flow reactor can be respectively and parallelly connected with a plurality of reaction pipes, so that continuous production of automatic control batching-low temperature reaction-high temperature reaction-distillation reaction in different equipment can be realized;
5. the traditional single-pot method has the defects that the reaction condition is inconvenient to change in the reaction process, the heat released by the reaction cannot be timely discharged, and local overheating is easy to generate, and the unit heat exchange area of the plug flow reactor adopted by the invention is large, and the heat exchange is sufficient and timely, so that the reaction temperature is easy to control and controllable, the generation of byproducts is reduced, and the reaction yield is improved. The yield of the produced nitromethane can reach more than 80 percent, and the purity is more than 99.5 percent.
6. Compared with the traditional reaction kettle type reaction, the reaction continuity generated by the plug flow reactor is strong, the required reaction time is shorter, the reaction rate is higher, and the automatic control and emergency cutting are easier to realize. The liquid holdup in the plug flow reactor is less than 1/50 or even 1/100 of that in the existing reaction kettle, the safety risk is controllable, the production is stable, the yield is improved, and the industrial popularization can be carried out. The production cost of each ton of nitromethane product can be reduced by about 1600 yuan.
Detailed Description
It should be noted that in this application, relational terms such as "first" and "second" and the like are used to distinguish one entity or operation from another entity or operation. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Unless defined otherwise, all scientific and technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention relates.
Various publications, patents, and published patent specifications cited herein are incorporated by reference in their entirety.
The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Examples are as follows:
example 1
230 ml of water is added with 345 g (5 mol) of sodium nitrite, 315.3 g (2.5 mol) of dimethyl sulfate and 8.6 g of sodium carbonate, and the mixture is mixed by a static mixing device and pumped into a first plug flow reactor, wherein the inside of the reactor is provided with 26 parallel tubes, and the inside diameter size is thatThe first plug flow reactor is 0.5m long, stainless steel is selected, the temperature of a hot zone of the first plug flow reactor is controlled at 30 ℃ through a temperature control system, the pressure is 0.1MPa, the flow rate is set to 20mL/min, the obtained first reaction liquid is continuously pumped into a second plug flow reactor, the structure of the reactor is the same as that of the first plug flow reactor, the temperature of the hot zone of the reactor is controlled at 80 ℃, the pressure is 0.1MPa, the flow rate is also set to 10mL/min, the obtained second reaction liquid is continuously fed into a distillation tower, the temperature of the distillation tower is controlled at 100-110 ℃, continuous distillation is continuously carried out along with the continuous inlet of the reaction liquid, the distilled product is continuously produced, the nitromethane crude product is obtained after standing and layering, the tower bottom liquid is collected from the bottom of the distillation tower, the nitromethane crude product is obtained after distillation recovery of the distillation tower, the nitromethane crude product is combined, the nitromethane crude product is rectified again, and the nitromethane product is 244.6 g, the purity is 99.51%, and the yield is 80.14%.
Example 2
Adding 1380 g (20 mol) of sodium nitrite, 1261.3 g (10 mol) of dimethyl sulfate and 34.5 g of sodium carbonate into 920 ml of water, mixing by a static mixing device, pumping into a first plug flow reactor, wherein the reactor is provided with 16 parallel tubes with the inner diameter size1m long, selecting an aluminum plastic composite pipe,the temperature of a hot zone of a first plug flow reactor is controlled at 40 ℃ through a temperature control system, the pressure is 0.15MPa, the flow rate is set to 100mL/min, the obtained first reaction liquid is continuously pumped into a second plug flow reactor, the structure of the reactor is the same as that of the first plug flow reactor, the temperature of the hot zone is controlled at 90 ℃, the pressure is 0.15MPa, the flow rate is set to 100mL/min, the obtained second reaction liquid is continuously fed into a distillation tower, the temperature of the distillation tower is controlled at 100-110 ℃, continuous distillation is continuously carried out along with the continuous entering of the reaction liquid, the distilled product is continuously produced, the nitromethane crude product is obtained after standing and layering, the tower bottom liquid is collected from the tower bottom of the distillation tower, the nitromethane crude product is obtained after distillation and recovery by the distillation tower, 1037.3 g of the nitromethane crude product is obtained after distillation, the nitromethane product is combined, the purity is 99.93%, and the yield is 85.02%.
Example 3
920 ml of water are added into 1449 g (21 mol) of sodium nitrite, 1261.3 g (10 mol) of dimethyl sulfate and 55.2 g of sodium carbonate, mixed by a static mixing device and pumped into a first plug flow reactor, wherein the inside of the reactor is provided with 10 parallel U-shaped pipes, and the inside diameter size is that of the first plug flow reactorThe first plug flow reactor is provided with a pipeline with the length of 2m, copper pipes are selected, the temperature of a hot zone of the first plug flow reactor is controlled at 35 ℃ through a temperature control system, the pressure is 0.15MPa, the flow rate is set to 400mL/min, the obtained first reaction liquid is continuously pumped into a second plug flow reactor, the pipeline structure of the second plug flow reactor is the same as that of the first plug flow reactor, the temperature of the hot zone of the second plug flow reactor is controlled at 100 ℃, the pressure is 0.15MPa, the flow rate is set to 400mL/min, the obtained second reaction liquid is continuously fed into a distillation tower, the temperature of the distillation tower is controlled at 100-110 ℃, the continuous distillation is continuously carried out along with the continuous entering of the reaction liquid, the distilled product is continuously produced, the nitromethane crude product is obtained after static layering, the tower bottom liquid is collected from the tower bottom of the distillation tower, the nitromethane crude product is obtained through distillation recovery of the distillation tower, 1065.6 g of the nitromethane crude product is combined, the nitromethane crude product is rectified, and the nitromethane product is obtained, the purity is 99.98%, and the yield is 87.34%.
Example 4
Will be 27.3 kgDissolving sodium bicarbonate in 920L water, adding 1380 kg (20 kmol) sodium nitrite and 1261.3 kg (10 kmol) dimethyl sulfate, mixing in static mixer, and pumping into a first plug flow reactor with 10 coils connected in parallel and having inner diameterThe pipeline length of the first plug flow reactor is 10m, stainless steel is selected, the temperature of the hot zone of the first plug flow reactor is controlled at 35 ℃ through a temperature control system, the pressure is 0.2MPa, the flow rate is set to be 10L/min, the obtained first reaction liquid is continuously pumped into the second plug flow reactor, and the reactor is identical to the first plug flow reactor, and the temperature of the hot zone of the reactor is controlled at 90 ℃, and the pressure and the flow rate are also the same. The obtained second reaction liquid is continuously fed into a distillation tower, the temperature of the distillation tower is controlled to be 100-110 ℃, continuous distillation is continuously carried out along with the continuous entering of the reaction liquid, distilled products are continuously produced, a nitromethane crude product is obtained after standing and layering, tower bottom liquid is collected from the tower bottom of the distillation tower, the distillation tower is used for distillation and recovery to obtain the nitromethane crude product, the nitromethane crude products are combined and then rectified, and 1050.6 kg of the nitromethane product is obtained, the purity is 99.92%, and the yield is 86.11%.
Example 5
Adding 1380 kg (20 kmol) of sodium nitrite, 1261.3 kg (10 kmol) of dimethyl sulfate and 34.5 kg of sodium carbonate into 920L of water, mixing by a static mixing device, pumping into a first plug flow reactor, wherein the reactor is provided with 9 parallel tubes, and the inner diameter size is thatThe pipeline length of the first plug flow reactor is 5m, stainless steel is selected, the temperature of the hot zone of the first plug flow reactor is controlled at 50 ℃ through a temperature control system, the pressure is 0.2MPa, the flow rate is set to 400L/min, the obtained first reaction liquid is continuously pumped into a second plug flow reactor, the structure of the reactor is the same as that of the first plug flow reactor, the temperature of the hot zone of the reactor is controlled at 100 ℃, the pressure is 0.2MPa, the flow rate is set to 400L/min, the obtained second reaction liquid is continuously fed into a distillation tower, the temperature of the distillation tower is controlled at 100-110 ℃, the continuous distillation is continuously carried out along with the continuous entering of the reaction liquid, and the distillation is continuously carried outContinuously producing the product, standing and layering to obtain a nitromethane crude product, collecting tower bottom liquid from the tower bottom of a distillation tower, distilling and recovering the nitromethane crude product by using another distillation tower to obtain the nitromethane crude product, merging the nitromethane crude products, and rectifying to obtain 995.6 kg of the nitromethane product, wherein the purity is 99.61%, and the yield is 81.28%.
Examples 4 and 5 are examples of industrial production, and if continuous production is required for a long time (for example, several days), the next batch of raw materials can be fed into the static mixing device after the previous batch of raw materials approaches the reaction, and the raw materials are fully mixed and fed continuously, so that the purpose is achieved.
Comparative example 1
1380 g (20 mol) of sodium nitrite, 34.5 g of sodium carbonate and 920 ml of water are respectively added into a reaction vessel, 1261.3 g (10 mol) of dimethyl sulfate is dripped in within half an hour, stirring and heating are carried out, the temperature is controlled below 70 ℃, after distillation for 2 hours, the crude product of nitromethane is obtained after standing and layering, and then the crude product is rectified, thus obtaining 721.1 g of nitromethane with the purity of 99.51% and the yield of 59.1%.
Comparative example 2
Adding 1380 kg (20 mol) of sodium nitrite, 1261.3 g (10 mol) of dimethyl sulfate and 34.5 g of sodium carbonate into 920 ml of water, mixing by a static mixing device, pumping into a first plug flow reactor, wherein the reactor is provided with 16 parallel tubes, and the inner diameter size is equal to that of the first plug flow reactor2m long, selecting an aluminum-plastic composite pipe, controlling the temperature of a hot zone of a first plug flow reactor to be 50 ℃, controlling the pressure to be 0.15MPa and the flow rate to be 100mL/min through a temperature control system, continuously feeding the obtained reaction liquid into a distillation tower, controlling the temperature of the distillation tower to be 100-110 ℃, standing and layering a distillation product to obtain a nitromethane crude product, and rectifying the nitromethane crude product to obtain 436.2 g of nitromethane product with the purity of 99.22 percent and the yield of 35.7 percent.
Comparative example 3
1380 kg (20 mol) of sodium nitrite, 1261.3 g (10 mol) of dimethyl sulfate and 34.5 g of sodium carbonate are added into 920 ml of water, and mixed by a static mixing device, and pumped into a first plug flow reactor, wherein the inside of the reactor is16 parallel tubes with inner diameter2m long, selecting an aluminum-plastic composite pipe, controlling the temperature of a hot zone of a first plug flow reactor to be 80 ℃ through a temperature control system, controlling the pressure to be 0.15MPa, setting the flow rate to be 100mL/min, continuously feeding the obtained reaction liquid into a distillation tower, controlling the temperature of the distillation tower to be 100-110 ℃, standing and layering a distillation product to obtain a nitromethane crude product, and rectifying the nitromethane crude product to obtain 798.6 g of nitromethane product with the purity of 99.56% and the yield of 65.4%.
It can be seen that the reaction was carried out by directly heating up to 80℃with only one plug flow reactor, similarly to the one-pot reaction of comparative example 1, and although the effect of a certain plug flow reactor could be exhibited, the ideal yield could not be fully achieved.
Comparative example 4
Adding 1380 kg (20 mol) of sodium nitrite, 1261.3 g (10 mol) of dimethyl sulfate and 34.5 g of sodium carbonate into 920 ml of water, mixing by a static mixing device, pumping into a first plug flow reactor, wherein the reactor is provided with 16 parallel tubes, and the inner diameter size is equal to that of the first plug flow reactor2m long, an aluminum plastic composite pipe is selected, the temperature of the hot zone of the first plug flow reactor is controlled at 25 ℃ through a temperature control system, the pressure is 0.15MPa, the flow rate is set to 100mL/min, and the target product nitromethane can not be obtained.
The reaction temperature is too low (lower than 30 ℃) and the reaction cannot be carried out, the reaction temperature is too high (higher than 100 ℃), and the chemical reaction is too severe, which is unfavorable for controlling the production safety.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is to be construed as including any modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
The foregoing embodiments and methods described in this invention may vary based on the capabilities, experience, and preferences of those skilled in the art.
The listing of the steps of a method in a certain order in the present invention does not constitute any limitation on the order of the steps of the method.
Claims (10)
1. A continuous flow synthesis method of nitromethane, comprising the steps of:
(1) Mixing dimethyl sulfate, nitrite, a catalyst and water to obtain a mixture;
(2) Continuously feeding the mixture obtained in the step (1) into a first reactor, and reacting at a first temperature to obtain a first reaction solution;
(3) Continuously feeding the first reaction liquid into a second reactor, and reacting at a second temperature to obtain a second reaction liquid;
(4) Continuously feeding the second reaction liquid into a distillation tower to obtain a nitromethane crude product, and rectifying to obtain a nitromethane product;
the first reactor and the second reactor are plug flow reactors, and the first temperature is smaller than the second temperature.
2. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the feeding in step (1) is performed by adding the material containing water but not containing nitrite to the material containing nitrite but not containing water.
3. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the plug flow reactor is provided with a temperature control system;
straight pipes, coil pipes, U-shaped pipes and tubes or any combination pipelines connected in series or in parallel are arranged in the plug flow reactor.
4. The method of claim 3, wherein the step of,
the pipeline is made of a metal pipe, a plastic composite metal pipe or a plastic pipe, and is preferably a metal pipe;
preferably, the metal tube is a galvanized tube, a copper tube or a stainless steel tube;
preferably, the plastic-composite metal pipe is an aluminum-plastic composite pipe;
preferably, the plastic tube is a PVC tube or a PE tube.
5. The method of claim 3, wherein the step of,
the inner diameter of the pipeline of the plug flow reactor1.0-25.0mm, preferably 2-10mm; the length is 0.5-15m, preferably 0.5-2m.
6. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the first temperature is 30-50 ℃, preferably 30-35 ℃;
the second temperature is 80-100 ℃, preferably 90-100 ℃.
7. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the reaction pressure in the first reactor and the second reactor is 0.1-0.2MPa.
8. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the nitrite is sodium nitrite or potassium nitrite;
the catalyst is alkali or strong alkali weak acid salt;
preferably, the base is sodium hydroxide or potassium hydroxide;
preferably, the strong base weak acid salt is sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.
9. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the molar ratio of the dimethyl sulfate to the nitrite is 1:2-2.2.
10. The method according to any one of claims 1 to 5, wherein,
the distillation temperature in the step (4) is 100-110 ℃;
preferably, the distillation in step (4) is an atmospheric distillation;
preferably, step (4) further comprises the step of recovering nitromethane from the bottoms of the distillation column.
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| CN202211558842.XA CN117466740A (en) | 2022-12-06 | 2022-12-06 | Continuous flow synthesis method of nitromethane |
| PCT/CN2023/128567 WO2024120073A1 (en) | 2022-12-06 | 2023-10-31 | Continuous-flow synthesis method for nitromethane |
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Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1039048B (en) * | 1956-01-27 | 1958-09-18 | Degussa | Process for the continuous production of nitroalkanes |
| RU2045514C1 (en) * | 1991-03-21 | 1995-10-10 | Гареев Гегель Амирович | Process for preparing nitromethane |
| RU2109728C1 (en) * | 1993-12-09 | 1998-04-27 | Гегель Амирович Гареев | Method of nitromethane synthesis |
| RU2076094C1 (en) * | 1995-04-14 | 1997-03-27 | Гегель Амирович Гареев | Method for production of nitromethane |
| CN102659602B (en) * | 2012-04-13 | 2014-07-16 | 湖北远大富驰医药化工股份有限公司 | Novel method for producing nitromethane |
| CN103553924B (en) * | 2013-10-21 | 2015-03-25 | 石家庄铁道大学 | Method for synthesizing nitromethane |
| CN105601520B (en) * | 2016-03-16 | 2018-07-03 | 临沂远博化工有限公司 | A kind of nitromethane synthesis and product separator |
| CN107857703B (en) * | 2017-09-14 | 2024-02-09 | 北京凯瑞英科技有限公司 | Reactor and method for continuously producing nitromethane |
| CN218981525U (en) * | 2022-12-06 | 2023-05-09 | 湖北富博化工有限责任公司 | Continuous flow synthesis system of nitromethane |
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