Method for preparing trifluoroethylamine through continuous ammonolysis by using microchannel method

Abstract

The invention discloses a method for preparing trifluoroethylamine through continuous ammonolysis by using a microchannel method. The method comprises the following steps: (1) mixing chlorotrifluoroethane with an organic solvent I to obtain an A-phase solution; mixing ammonia gas, a surfactant and an organic solvent II to obtain a B-phase solution; and (2) simultaneously feeding the A-phase solution and the B-phase solution into a micro-channel reactor according to a certain flow rate, heating to 50-110 DEG C, and carrying out ammonolysis reaction to obtain trifluoroethylamine. According to the preparation method disclosed by the invention, the high conversion rate of the substrate and the high selectivity and high yield of the target product can be ensured, the preparation process is simple in condition and short in time consumption, the prepared TFEA refined product is more convenient to realize industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine chemical industry, and particularly relates to a method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method. Background Art

[0002] Trifluoroethylamine (TFEA) is a colorless, transparent liquid with an ammonia smell. The trifluoromethyl group gives it significant chemical stability, strong electron-withdrawing properties and lipophilicity, resulting in its unique physicochemical properties. Trifluoroethylamine is widely used in fine chemicals such as dyes, pesticides, and pharmaceuticals, and is an important fluorine-containing intermediate and raw material. In the field of dyes, the addition of trifluoroethyl makes the dye color more vivid and less prone to fading. In the field of pesticides, trifluoroethylamine participates in the synthesis of pyrimidine, pyrazole and pyrrole pesticides, helping to prevent and control invertebrate pests and solve drug resistance problems. In the field of medicine, trifluoroethylamine is a synthetic raw material for a variety of drug intermediates and APIs, used to treat cardiovascular diseases, mental illnesses, and immune regulation disorders. In short, trifluoroethylamine, as a fluoride intermediate, has a wide range of application value. At present, some literature has reported its related synthesis methods, such as:

[0003] Patent GB717232 discloses a method using trifluoroacetamide as a raw material, dissolving it in anhydrous ether or tetrahydrofuran, slowly adding a reducing agent, lithium aluminum hydride, to react to obtain 2,2,2-trifluoroethylamine hydrochloride, and then converting the trifluoroethylamine hydrochloride into trifluoroethylamine. The advantages of this method are that the reaction steps are few and the amide can be reduced to amine under mild conditions, but the disadvantages are that the reaction is accompanied by side reactions, the yield of trifluoroethylamine is only 75.1%, and the cost of trifluoroacetamide is high, which is not conducive to large-scale industrial production.

[0004] Patent CN109096121 discloses a method using trifluoroacetaldehyde as a raw material, which is mixed with ammonia water and then introduced into a tubular reactor filled with a molecular sieve-loaded catalyst, and undergoes a condensation-reduction reaction with ammonium formate as a hydrogen donor to obtain a product mixture containing an imine intermediate, and then deammoniation and cooling, and then transferred to a stirred tank, reacted under a nitrogen atmosphere and a secondary reducing agent, and after the reaction is completed, refined trifluoroethylamine is obtained by vacuum distillation and rectification. The advantage of this method is that the reaction conditions are relatively mild, but the disadvantage is that the reaction process is relatively cumbersome, and it is necessary to undergo two reductions to obtain a crude product. The impurities such as the imine intermediate, ammonium formate, and the reducing agent present therein also make the post-processing steps more complicated. At the same time, trifluoroacetaldehyde is extremely unstable, and the raw material storage and transportation are difficult, and the cost is expensive, so it is also difficult to industrialize.

[0005] Patent US4618718 discloses a method using trifluoromonochloroethane (R133a) as a raw material, using an intermittent process, adding R133a, a solvent and ammonia to a high-temperature and high-pressure reactor, the reaction temperature is 200-220°C, the reaction pressure is 7-11MPa, the reaction time is 24h, and the yield of trifluoroethylamine is 86.8%. The advantage of this method is that the selected raw material R133a has a complete process production route, the cost is relatively low, and due to the current control of chlorofluorocarbons, it is necessary to develop downstream products of R133a, so R133a is further converted into TFEA by ammonolysis, which is also a potential use for R133a. However, the disadvantage of this method is that the reaction temperature and reaction pressure are high, and the equipment requirements are relatively large. If it is carried out in large-scale industrial production, it will bring considerable safety risks and challenges.

[0006] Patent CN201010525312 also discloses a method using R133a as a raw material, wherein liquid R133a dissolved in glycerol is mixed with ammonia water with a concentration of 30%wt-100%wt, wherein the molar ratio of ammonia to R133a is 8-15:1, and then enters a tubular reactor for reaction at a temperature of 150-200°C, a pressure of 2-4MPa, and a time of 20-30min, and then a crude product is flashed for deamination, and then sodium carbonate is added to the liquid after deamination treatment for neutralization and then vacuum distillation is performed to obtain trifluoroethylamine with a yield of 95.6%. Compared with patent US4618718, this method significantly shortens the reaction time and improves the yield to a certain extent, but uses a large amount of high-concentration ammonia water, and the ammonia source is far in excess relative to R133a, which brings greater harm to the environment and does not meet the production requirements of green chemical industry. At the same time, the reaction temperature has no significant improvement.

[0007] From the perspective of industrial production cost and economic feasibility, the preparation of trifluoroethylamine by ammonolysis of R133a is a more appropriate solution. At present, most of the production processes in the process of preparing TFEA by ammonolysis of R133a are accompanied by high temperature and high pressure reaction conditions, and the reaction time is long, which poses a great safety risk.

[0008] A microchannel reactor is a device that performs chemical reactions at a microscale (usually micrometer or millimeter level), and is a chemical reactor that mixes, heats, reacts, and separates reactants through multiple narrow channels (microchannels). Microchannel reactors have a large surface area, and reactors of the same volume can provide more reaction surfaces, thereby increasing the reaction rate. In addition, the short distance in the microchannel can accelerate the mass transfer between reactants and avoid the phenomenon of reactant retention. At the same time, the heat conduction efficiency of the microchannel is high, and the heat exchange effect between the reactor surface and the cooling system is good, so the reaction temperature can be controlled more accurately. Rapid heating or cooling of reactants in the microchannel prevents side reactions or incomplete reactions caused by excessively high or low temperatures.

[0009] Patent CN111138292A discloses a method for preparing TFEA by a microchannel method, and describes the specifications of the microchannel in detail. The TFEA yield shown in the embodiment can reach 94%-95%. However, in the embodiment, the reaction temperature mentioned is as low as 110°C and as high as 190°C, and the energy demand is still large. There is no clear explanation of other reaction conditions such as the reaction residence time. At the same time, in the embodiment, the solvent used in the process of converting R133a into TFEA is not clearly explained. In addition, the R133a and NH 3 The molar ratio is 3:1, which means that the conversion rate of R133a in a single reaction process can only reach a maximum of 33.3%. Summary of the invention

[0010] In view of the above problems, the present invention discloses a method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method, which can ensure a high conversion rate of the substrate, and a high selectivity and a high yield of the target product, and the preparation process conditions are simple, the time consumption is short, and the TFEA fine product is prepared, which is more convenient for industrial production.

[0011] The specific technical solutions are as follows:

[0012] A method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method, comprising:

[0013] (1) mixing trifluorochloroethane and organic solvent I to obtain a phase A solution; mixing ammonia, a surfactant and organic solvent II to obtain a phase B solution;

[0014] (2) The phase A solution and the phase B solution are simultaneously fed into a microchannel reactor at a certain flow rate, and heated to 50-110° C. to perform an ammonolysis reaction to obtain trifluoroethylamine.

[0015] The preparation method disclosed in the present invention uses a microchannel reactor, uses R133a as a substrate, and uses ammonia as an ammonia source to react R133a with NH 3 The reaction is carried out in the liquid phase, where the choice of solvent is influenced by the R133a and NH 3 The obvious difference in hydrophilicity between NH 3 It is extremely hydrophilic, while R133a is extremely hydrophobic. Therefore, it is necessary to screen out an excellent reaction solvent system that is conducive to the reaction of R133a with NH 3To form a homogeneous phase, in addition to a suitable reaction solvent, the selection of a surfactant is also crucial. In the present invention, the surfactant can promote the formation of bubbles and the dissolution of gas, increase the contact area between R133a and ammonia and the reaction solvent, thereby accelerating the reaction rate; and in the case where the reactants are not easily mixed, the surfactant can promote the uniform dispersion of the reactants by reducing the interfacial tension. At the same time, the hydrophilic and lipophilic properties of the surfactant can affect the solubility of the reactants, thereby changing their activity. In the mass transfer process between the solvent and the reactants, the surfactant can increase the solubility of the reactants in the solvent or change the properties of the solvent, making it easier for the reactants to participate in the reaction.

[0016] In step (1):

[0017] Preferred:

[0018] The organic solvent I is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, ethylene glycol, glycerol, 1,4-dioxane, N,N-dimethylacetamide, and toluene;

[0019] The organic solvent II is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, ethylene glycol, glycerol, 1,4-dioxane, N,N-dimethylacetamide, and toluene;

[0020] To simplify production, organic solvent I and organic solvent II are selected from the same type.

[0021] Further preferably,

[0022] The organic solvent I is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, and ethylene glycol;

[0023] The organic solvent II is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide and ethylene glycol.

[0024] Preferred:

[0025] The surfactant is selected from one or more of hexadecyltrimethylammonium bromide, polyvinyl alcohol, polyethylene glycol, sodium octylphenoxyacetate, sodium lauryl sulfate, octadecyltrimethylammonium chloride, polysorbate 80, trioctylmethylammonium chloride, polydimethylsiloxane, hexadecylamidopropyltrimethylammonium chloride, polyvinylpyrrolidone, and behenyl disulfonate;

[0026] More preferably, the surfactant is selected from hexadecyltrimethylammonium bromide and / or hexadecanoylamidopropyltrimethylammonium chloride.

[0027] It has been found through experiments that the reaction system composed of the above-mentioned organic solvent and a mixture of an organic solvent and a surfactant can promote the reaction activity of R133a and ammonia, ensure a high conversion rate of the substrate, and a high selectivity and high yield of the target product.

[0028] In step (1):

[0029] Preferred:

[0030] In the phase A solution, the mass ratio of trifluorochloroethane to the organic solvent I is 1:(1-16); specifically, it can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16 or any ratio within the above range;

[0031] More preferably, the mass ratio of the two is 1:(1-12); more preferably, it is 1:(2-12).

[0032] Preferred:

[0033] When preparing the phase A solution, an inert gas is used for pressure protection.

[0034] Preferred:

[0035] In the phase B solution, the mass ratio of ammonia gas to organic solvent II is 1:(3-10), specifically 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any ratio within the above range;

[0036] More preferably, in the phase B solution, the mass ratio of ammonia gas to organic solvent II is 1:(3-5); more preferably 1:5.

[0037] Preferred:

[0038] In the phase B solution, the mass ratio of the surfactant to the ammonia gas is (0.01-10):100, specifically 0.01:100, 0.05:100, 0.1:100, 0.5:100, 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100 or any ratio within the above range;

[0039] More preferably, in the phase B solution, the mass ratio of the surfactant to the ammonia gas is (0.05-7):100; more preferably (2-5):100; and even more preferably (3.5-5):100.

[0040] Preferred:

[0041] When preparing the phase B solution, an inert gas is used for pressure protection.

[0042] In step (2):

[0043] Preferred:

[0044] The flow rate of phase A solution is 1 to 4 mL / min; specifically, it can be 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min or any value within the above range; more preferably, the flow rate of phase A solution is 1 to 3 mL / min.

[0045] Preferred:

[0046] The flow rate of the phase B solution is 1 to 8 mL / min; specifically, it can be 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min, 4.5 mL / min, 5 mL / min, 5.5 mL / min, 6 mL / min or any value within the above range; more preferably, the flow rate of the phase B solution is 1 to 6 mL / min.

[0047] Preferred:

[0048] The flow ratio of the phase A solution to the phase B solution is 1:(0.3-3.0); specifically, it can be 1:0.3, 1:0.5, 1:0.8, 1:1, 1:1.5, 1:2, 1:2.5, 1:3 or any ratio within the above range;

[0049] More preferably, the flow ratio of the phase A solution to the phase B solution is 1:(1-2).

[0050] Preferred:

[0051] The total flow rate of the phase A solution and the phase B solution is controlled at 1 to 12 mL / min; specifically, it can be 1 mL / min, 2 mL / min, 3 mL / min, 4 mL / min, 5 mL / min, 6 mL / min, 7 mL / min, 8 mL / min, 9 mL / min, 10 mL / min, 11 mL / min, 12 mL / min or any value within the above range.

[0052] Experiments have shown that the continuous optimization of the above-mentioned raw material composition, flow rate and other parameters can promote the reaction activity of R133a and ammonia, ensuring a high conversion rate of the substrate, and a high selectivity and high yield of the target product.

[0053] Preferred:

[0054] In step (2), the microchannel reactor is equipped with 5 to 10 microreactors of the same structure connected in series; specifically, it can be 5, 6, 7, 8, 9, or 10 microreactors.

[0055] More preferably, the number of microreactors connected in series is 8 to 10.

[0056] Preferred:

[0057] In step (2), the temperature of the ammonolysis reaction is 80-110°C; specifically, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or any value within the above range.

[0058] More preferably, the temperature is 80°C.

[0059] Since the reaction system used in the present invention is to react the raw materials R133a and NH 3 The crude TFEA and the product TFEA all showed excellent solubility, which also means that the difficulty of separating the products after the reaction will increase. Based on this, the present method further proposes a distillation process suitable for preparing crude TFEA in the reaction system to obtain fine TFEA.

[0060] Preferably, in step (2), the reaction solution obtained after the ammonolysis reaction is subjected to two-stage distillation, comprising:

[0061] Stage I distillation: The reaction liquid is passed into the distillation tower kettle to start stage I distillation. When the kettle rises from room temperature to 50-60°C, it starts to boil and discharge NH 3 Components; continue to heat up to 100°C, and start to extract after the reflux is stable; when there is no reflux liquid at this temperature, heat up 10-20°C in full reflux mode, and extract at a reflux ratio of 1:1 after the system is stable, until the temperature rises to the boiling point of the reaction liquid and no reflux condensate is distilled;

[0062] Stage II distillation: The produced liquid from stage I distillation is passed into the bottom of the distillation tower to start stage II distillation. The initial temperature of the bottom of the tower is set at 20°C and slowly raised to 45°C. In the early stage of stage II distillation, total reflux is used and the condensation temperature is controlled at -20 to -10°C. The product is tested and mined after the purity of TFEA is not less than 99%.

[0063] Compared with the prior art, the present invention has the following beneficial results:

[0064] The present invention discloses a method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method. R133a is used as a raw material and ammonia gas is used as an ammonia source. Since the hydrophilicity and hydrophobicity of the two are quite different, the reaction conditions are relatively demanding. The present invention proposes a microchannel, a preferred solvent and a surfactant strategy to solve the problem.

[0065] At the same time, due to the reaction system mentioned in the present invention, the raw materials R133a and NH 3 The crude TFEA and the product TFEA all showed excellent solubility, which also means that the difficulty of separating the products after the reaction will increase. Based on this, the present invention also proposes a two-stage distillation process suitable for preparing crude TFEA in the reaction system to obtain fine TFEA.

[0066] The preparation method disclosed by the invention shortens the reaction time, improves the time-space yield, reduces the energy consumption, and the substrate conversion rate can reach up to 99.8%, the product yield can reach up to 98.5%, and the purity can reach 99.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 The gas phase diagram of the raw material obtained by mixing the phase A solution and the phase B solution in Example 1;

[0068] Figure 2 is a product gas phase diagram of the reaction solution prepared in Example 1;

[0069] Figure 3 for Figure 1 The fragment mass spectrum of the substance with the peak at 5.5min;

[0070] Figure 4 for Figure 2 Fragmentation mass spectrum of the substance with the peak at 4.6 min. DETAILED DESCRIPTION

[0071] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] In the description of the present invention, it should be noted that, for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances. Below, according to the overall structure of the present invention, its embodiments are described. Unless otherwise specified, the raw materials in the embodiments of the present invention are purchased through commercial channels.

[0073] Example 1

[0074] (1) Weigh 600 g of N-methylpyrrolidone, evacuate, connect the R133a cylinder to the liquefied gas cylinder 1, open the valve, introduce 300 g of R133a at room temperature to obtain a phase A solution, connect the nitrogen cylinder to the liquefied gas cylinder 1, and maintain a certain nitrogen pressure; weigh 600 g of N-methylpyrrolidone (unless otherwise specified, the organic solvent I and the organic solvent II in the present invention are of the same type), add it to the liquefied gas cylinder 2, add 4.2 g of hexadecyltrimethylammonium bromide to the liquefied gas cylinder 2 according to a mass ratio of 3.5 wt%, evacuate, and add NH 3 The cylinder is connected to the liquefied gas cylinder 2, the valve is opened, and 120gNH 3 Prepare the phase B solution, connect the nitrogen cylinder to the liquefied gas cylinder 2, and maintain a certain nitrogen pressure.

[0075] (2) Start feeding the 316L microchannel reactor, connect the plunger pump 1 to the liquefied gas cylinder 1, control the flow rate of the phase A solution to 3 mL / min, connect the plunger pump 2 to the liquefied gas cylinder 2, control the flow rate of the phase B solution to 3 mL / min (after conversion, the molar ratio of R133a to ammonia is 1:3), use 10 microreactors as the device, control the reaction temperature at 80°C, and the residence time is 15 min.

[0076] (3) The reaction liquid is collected and subjected to two-stage distillation. A φ3×50cm distillation column is used. The filler is a triangular spiral 316L stainless steel. The theoretical number of plates is 50-70 / m (i.e., the number of device plates is about 25-35). The distillation column is insulated with a vacuum jacket; the connection between the distillation head and the distillation column is insulated with a wrapped insulation belt; the top condensation uses two condenser tubes in series, and the condensate inlet temperature is -20°C. In order to ensure the condensation of low-boiling components, copper tubes are wrapped around the bottom of the condenser, the U-tube and the outer wall of the receiver of the distillation device, and cooled with low-temperature circulating liquid. At the same time, the outlet of the non-condenser is connected to a gas washing bottle filled with NMP to capture low-boiling components that cannot be condensed: NH 3 and R133a.

[0077] Stage I distillation: Weigh 850g of the reaction solution into a 1000mL distillation flask and place it in the tower. Check the air tightness and start distillation. The tower starts to heat up slowly from room temperature. When the temperature reaches about 50-60℃, it starts to boil and discharge NH 3 When the kettle temperature rises to 100°C and the reflux stabilizes, extraction begins at a reflux ratio of 1:1. When there is no reflux liquid at this temperature, the temperature is raised by 20°C in the full reflux mode, and after the system stabilizes, extraction is continued at a reflux ratio of 1:1 until the temperature rises to the boiling point of the reaction liquid and no reflux condensate is distilled out.

[0078] Stage II distillation: Set the initial temperature of the tower bottom to 20°C, slowly raise the temperature to 45°C, use full reflux at the beginning of stage II distillation, and control the temperature of the condenser at -20~-10°C. Detect the solution in the U-tube, and mine after the TFEA purity is qualified. Separate and obtain TFEA with a purity of 99.7%. After testing, the conversion rate of R133a is 99.8%, and the yield of TFEA is 97.7%.

[0079] Figure 1 This is a gas phase diagram of the raw material obtained by mixing the phase A solution and the phase B solution in this embodiment;

[0080] Figure 2 is a product gas phase diagram of the reaction solution prepared in this example; Figure 3 for Figure 1 The fragment mass spectrum of the substance with the peak at 5.5min (the upper figure is the detection spectrum, and the lower figure is the standard spectrum); Figure 4 for Figure 2 The fragment mass spectrum of the substance with the peak at 4.6 min (the upper figure is the detection spectrum, and the lower figure is the standard spectrum). Combining the four figures, it can be confirmed that this method can convert R133a into TFEA.

[0081] Embodiments 2 to 9

[0082] The preparation process is basically the same as that in Example 1, except that different organic solvents are used in preparing the phase A solution and the phase B solution. The specific types used and the data of R133a conversion rate and TFEA yield in each example are listed in Table 1 below.

[0083] Table 1

[0084]

[0085] Embodiments 10 to 20

[0086] The preparation process is basically the same as that in Example 1, except that the type of surfactant used in preparing the phase B solution is different. The specific types used and the data of R133a conversion rate and TFEA yield in each example are listed in Table 2 below.

[0087] Table 2

[0088]

[0089] Examples 21 to 24

[0090] The preparation process is basically the same as that in Example 1, except that the mass of R133a added when preparing the phase A solution is different. The specific mass, the adjusted mass ratio with organic solvent I, and the R133a conversion rate and TFEA yield data in each example are listed in Table 3 below.

[0091] Table 3

[0092]

[0093] a: After conversion, the molar ratio of R133a to ammonia in Example 21 is 1:2.

[0094] Examples 25 to 27

[0095] The preparation process is basically the same as that in Example 1, except that the mass of the surfactant used in preparing the phase B solution is different. The specific mass, the adjusted mass ratio with ammonia, and the R133a conversion rate and TFEA yield data in each example are listed in Table 4 below.

[0096] Table 4

[0097]

[0098] Embodiments 28 to 29

[0099] The preparation process is basically the same as that in Example 1, except that the mass of ammonia used in preparing the phase B solution is different. The specific mass, the adjusted mass ratio of ammonia to organic solvent II, and the R133a conversion rate and TFEA yield data in each example are listed in Table 5 below.

[0100] Table 5

[0101]

[0102] Embodiments 30 to 35

[0103] The preparation process is basically the same as that in Example 1, except that the flow rate and / or ratio of the phase A solution to the phase B solution are different. The specific ratios and the data of the R133a conversion rate and TFEA yield in each example are listed in Table 6 below.

[0104] Table 6

[0105]

[0106] b: After conversion, the molar ratio of R133a to ammonia in Example 30 is 1:1;

[0107] c: After conversion, the molar ratio of R133a to ammonia in Example 31 is 1:2.

[0108] Embodiments 36 to 37

[0109] The preparation process is basically the same as that in Example 1, except that the number of microchannel reactor blocks is different. The specific number of blocks and the data of R133a conversion rate and TFEA yield in each example are listed in Table 7 below.

[0110] Table 7

[0111]

[0112] Embodiments 38 to 39

[0113] The preparation process is basically the same as that in Example 1, except that the reaction temperature is different. The specific temperature and the R133a conversion rate and TFEA yield data in each example are listed in Table 8 below.

[0114] Table 8

[0115]

[0116] Comparative Example 1

[0117] The preparation process is basically the same as that in Example 1, except that the organic solvent used in preparing the phase A solution and the phase B solution is pyridine (the mass is the same as that in Example 1).

[0118] After testing, in this comparative example, the conversion rate of R133a was 54.2%, and the yield of TFEA was 43.7%.

[0119] Comparative Example 2

[0120] The preparation process is basically the same as that in Example 1, except that the surfactant is replaced with an equal mass of sodium dodecyl sulfate when preparing the phase B solution.

[0121] After testing, in this comparative example, the conversion rate of R133a was 49.7%, and the yield of TFEA was 35.8%.

[0122] Comparative Example 3

[0123] The preparation process is basically the same as that in Example 1, except that the reaction temperature is replaced with 150°C.

[0124] After testing, in this comparative example, the conversion rate of R133a was 99.9%, and the yield of TFEA was 55.6%.

[0125] Comparative Example 4

[0126] The preparation process is basically the same as that in Example 1, except that the reaction temperature is replaced with 30°C.

[0127] After testing, in this comparative example, the conversion rate of R133a was 5.4%, and the yield of TFEA was 3.9%.

[0128] The above-mentioned embodiments are preferred embodiments, but the protection scope of the present invention is not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above-mentioned embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method, characterized in that: include: (1) mixing trifluorochloroethane and organic solvent I to obtain a phase A solution; mixing ammonia, a surfactant and organic solvent II to obtain a phase B solution; (2) The phase A solution and the phase B solution are simultaneously fed into a microchannel reactor at a certain flow rate, and heated to 50-110° C. to perform an ammonolysis reaction to obtain trifluoroethylamine.

2. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 1, characterized in that: In step (1): The organic solvent I is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, ethylene glycol, glycerol, 1,4-dioxane, N,N-dimethylacetamide, and toluene; The organic solvent II is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, propylene glycol, ethylene glycol, glycerol, 1,4-dioxane, N,N-dimethylacetamide, and toluene; The surfactant is selected from one or more of hexadecyltrimethylammonium bromide, polyvinyl alcohol, polyethylene glycol, sodium octylphenoxyacetate, sodium lauryl sulfate, octadecyltrimethylammonium chloride, polysorbate 80, trioctylmethylammonium chloride, polydimethylsiloxane, hexadecylamidopropyltrimethylammonium chloride, polyvinylpyrrolidone, and behenyl disulfonate.

3. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 1, characterized in that: In step (1): In the phase A solution, the mass ratio of trifluorochloroethane to the organic solvent I is 1:(1-16); When preparing the phase A solution, an inert gas is used for pressurization protection; In the phase B solution, the mass ratio of ammonia to organic solvent II is 1:(3-10), and the mass ratio of surfactant to ammonia is (0.01-10):100; When preparing the phase B solution, an inert gas is used for pressure protection.

4. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 1, characterized in that: In step (2): The flow rate of phase A solution is 1 to 4 mL / min; The flow rate of phase B solution is 1-8 mL / min.

5. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 4, characterized in that: The flow ratio of phase A solution to phase B solution is 1:(0.3-3.0); The total flow rate of the phase A solution and the phase B solution is controlled at 1-12 mL / min.

6. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 1, characterized in that: In step (2), the microchannel reactor is equipped with 5 to 10 microreactors with the same structure connected in series.

7. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 1, characterized in that: In step (2), the reaction solution obtained after the ammonolysis reaction is subjected to two-stage distillation, comprising: Stage I distillation: The reaction liquid is introduced into the distillation tower kettle to start stage I distillation. When the kettle rises from room temperature to 50-60°C, it starts to boil and discharge NH3 components; the temperature is continued to rise to 100°C, and extraction begins after the reflux is stable; when there is no reflux liquid at this temperature, the temperature is raised by 10-20°C in the full reflux mode, and after the system is stable, extraction is continued at a reflux ratio of 1:1, until the temperature rises to the boiling point of the reaction liquid and no reflux condensate is distilled; Stage II distillation: The produced liquid from stage I distillation is passed into the bottom of the distillation tower to start stage II distillation. The initial temperature of the bottom of the tower is set at 20°C and slowly raised to 45°C. In the early stage of stage II distillation, total reflux is used and the condensation temperature is controlled at -20 to -10°C. The product is tested and mined after the purity of TFEA is not less than 99%.

8. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to any one of claims 1 to 7, characterized in that: In step (1): The organic solvent I is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, and ethylene glycol; The organic solvent II is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, and ethylene glycol; The surfactant is selected from hexadecyltrimethylammonium bromide and / or hexadecanoylamidopropyltrimethylammonium chloride.

9. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 8, characterized in that: In step (1): In the phase B solution, the mass ratio of ammonia gas to organic solvent II is 1:(3-5), and the mass ratio of surfactant to ammonia gas is (2-5):

100.

10. The method for preparing trifluoroethylamine by continuous ammonolysis using a microchannel method according to claim 9, characterized in that: In step (2): The temperature of the ammonolysis reaction is 80-110°C; There are 8 to 10 microreactors connected in series.

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