Gas-phase catalytic production of heptafluoroisobutyronitrile

Abstract

This application relates to a method, device, equipment, and medium for manufacturing an AA lithium-ion battery, including the steps of: obtaining a battery core through a battery core manufacturing process; selecting and stamping steel to manufacture the battery to obtain an upper steel shell of the battery; obtaining user needs and leaf spring property parameters and determining leaf spring bending parameters based on the user needs and the leaf spring property parameters; assembling a PCB board and the upper steel shell of the battery based on the leaf spring bending parameters, bending the negative leaf spring on the side of the PCB board downward to elastically contact the negative leaf spring with the upper steel shell, bending the positive leaf spring on the bottom of the PCB board downward to elastically contact the positive leaf spring with the top of the battery core, to obtain a complete step-down charging terminal; fitting the complete step-down charging terminal onto the battery core to obtain a semi-finished battery; and rolling and fixing the semi-finished battery along the roll grooves of the battery core and externally fitting an insulating film on the outside of the rolled and fixed semi-finished battery to obtain a finished battery. This application has the effect of improving the safety of lithium-ion batteries.

Description

[Technical Field]

[0001] The present invention relates to the production of heptafluoroisobutyronitrile, and more particularly to a process for producing heptafluoroisobutyronitrile by vapor phase catalytic dehydration. [Background technology]

[0002] Perfluoroisobutyronitrile (C4F7N) has low toxicity and excellent chemical stability, and its global warming potential (GWP) is 2400, which is only about 1 / 10 that of sulfur hexafluoride. Its ozone depletion potential (ODP) is 0, and its atmospheric lifetime is significantly shorter than that of sulfur hexafluoride, making it a promising alternative gas to sulfur hexafluoride. Currently, heptafluoroisobutyronitrile is mainly synthesized by the dehydration of heptafluoroisobutyronitrile, and the dehydration method is mainly dehydration with a dehydrating agent.

[0003] Patent US15997808A discloses a method for obtaining heptafluoroisobutyronitrile by dehydrating heptafluoroisobutyric amide using methyl heptafluoroisobutyrate and ammonia as raw materials, with a yield of 74.9%. Patent CN108395382A discloses a method for obtaining heptafluoroisobutyronitrile by dehydrating trifluoroacetic anhydride as a dehydrating agent, with a yield of 76%. Patent CN110642750A discloses a method for obtaining perfluoroalkyl amide by dehydrating a fluorine-containing carboxylic acid anhydride (e.g., trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluorobutyric anhydride and heptafluoroisobutyric anhydride) and N,N-dimethylformamide as a combined dehydrating agent. Patent CN107935884A discloses that the dehydrating agent mainly used in the dehydration of heptafluoroisobutyramide is one or more of trifluoroacetic anhydride, acetic anhydride, thionyl chloride, phosphorus pentoxide or phosphorus oxychloride, and the organic solvent used is one or more of pyridine, polyphosphoric acid, carbon tetrachloride, N,N-dimethylformamide, N,N-diethylformamide, 1,4-dioxane or dimethyl sulfoxide.

[0004] The process for dehydrating heptafluoroisobutyramide using a dehydrating agent has matured, but it has the following drawbacks: (1) it is an intermittent process, making it difficult to achieve large-scale continuous production; (2) it uses a large amount of dehydrating agent, which tends to generate a large amount of liquid or solid waste, and it is difficult to recover and reuse the spent dehydrating agent; and (3) it uses a large amount of solvent, which is difficult to recover and reuse due to the introduction of the dehydrating agent and its by-products, and it generates a large amount of waste liquid, causing serious environmental pollution.

[0005] Therefore, research into the catalytic dehydration of heptafluoroisobutyramide has been progressing gradually. Patent CN114105820A discloses a method for obtaining heptafluoroisobutyronitrile by dehydration of heptafluoroisobutyroamide under the action of a molecular sieve catalyst, and the molecular sieve catalyst used is at least one selected from HY molecular sieve, NaY molecular sieve, β molecular sieve, ZSM-5 molecular sieve, 3A molecular sieve, 4A molecular sieve, and 5A molecular sieve.

[0006] Patent CN114057605A discloses a method for producing nitriles by vapor-phase catalytic dehydration, wherein the dehydration catalyst used is a supported catalyst, the support of which is any one or more of silicon dioxide, molecular sieve, activated carbon, diatomaceous earth, montmorillonite, magnesium oxide, chromium oxide, iron oxide, nickel oxide, and zinc oxide, and the active component is any one or more of cobalt chloride, chromium chloride, zinc chloride, nickel chloride, iron chloride, and copper chloride.

[0007] Patent CN109320436A discloses a method for producing perfluoronitrile by gas phase catalysis, where the catalyst in the dehydration reaction is one or more of alumina, copper oxide, cobalt oxide or niobium oxide.

[0008] The catalytic dehydration method described above can reduce waste by more than 90% and costs by 30-40%, but it has drawbacks such as low catalyst selectivity, short life, difficulty in regeneration and activation, and poor reproducibility of reaction results. Summary of the Invention [Problem to be solved by the invention]

[0009] In order to solve the above technical problems, the present invention provides a method for producing heptafluoroisobutyronitrile using a gas-phase catalyst, which produces little waste, is low cost, has high catalytic activity, good product selectivity, good reaction reproducibility, has a long catalyst life, and is suitable for industrial continuous production. [Means for solving the problem]

[0010] The object of the present invention is achieved by the following technical solutions:

[0011] 1. A vapor phase catalytic production of heptafluoroisobutyronitrile, the process comprising: The method includes a step of obtaining heptafluoroisobutyronitrile by removing one molecule of water from heptafluoroisobutyroamide gas under the action of a catalyst, wherein the catalyst is an oxide of a siderophile element, and the siderophile element includes at least one medium siderophile element selected from tungsten, molybdenum, tin, or gallium, or at least one high siderophile element selected from osmium, iridium, ruthenium, rhenium, or titanium.

[0012] As a result of research, the present invention has found that moderate siderophile elements have characteristics such as small ionic radius, high electron charge, and strong polarizability, which make it easy to form complex anions in the reaction of the present invention and form relatively stable intermediates with the enol form of the amide. Therefore, the catalyst of the present invention is preferably an oxide of at least one moderate siderophile element selected from tungsten, molybdenum, tin, and gallium. More preferably, the catalyst of the present invention is molybdenum oxide and / or tungsten oxide.

[0013] The catalytic dehydration reaction temperature of the present invention is 150 to 600°C, the reaction pressure is 1 to 3 bar, and (τ-1)s≦residence time≦(τ+1)s, where τ is calculated according to the following formula: JPEG2025541647000002.jpg25170

[0014] In the equation, r is the radius of the reaction tube, h is the effective height of the reaction tube (i.e., the catalyst packing height), k is the catalyst packing factor, M = 213.05 g / mol, P is the reaction pressure, v is the feed rate, ρ = 1.517 g / mL, R = 8.314 J / (mol·K), and T is the reaction temperature.

[0015] Generally, the feed rate suitable for the present invention is 0.1 to 100 mL / min, the radius of the reaction tube is 10 to 300 mm, and the effective height of the reaction tube is 500 to 1000 mm, and therefore, the residence time is basically 0.1 to 50 s.

[0016] Preferably, the reaction temperature is 300 to 500° C., the reaction pressure is 1 to 2 bar, and the residence time is (τ−0.1) s≦residence time≦(τ+0.1) s.

[0017] The catalyst of the present invention is produced and obtained by the following steps: Concentrated ammonia is dropped into the metal salt solution to precipitate, and the temperature is controlled to be ≦80°C. The solution is left to stand for 12-24 hours for aging. After that, the precursor is obtained by distillation, crystallization, centrifugation, and drying. Finally, the catalyst is obtained by roasting. The metal salt solution is obtained by dissolving or dispersing a raw material containing a siderophile element in water (for example, deionized water).

[0018] The raw material containing a siderophile element is at least one selected from a metal acid, a metal acid salt, a metal alkoxide, a chloride, and an ammonium salt. Specifically, the metal acid may be tungstic acid, molybdic acid, or rhenic acid. The metal acid salt may be sodium tungstate, sodium molybdate, sodium perrhenate, or ruthenium acetate. The metal alkoxide may be tetrabutyl titanate or tetraethyl titanate. The chloride may be tungsten chloride, molybdenum chloride, tin chloride, titanium tetrachloride, osmium chloride, iridium chloride, or ruthenium chloride. The ammonium salt may be ammonium tungstate, ammonium paratungstate, ammonium molybdate, ammonium chloroosmate, ammonium chloroiridate, or the like.

[0019] The precursor produced and obtained by the above method is at least one of a hydroxide or an acid ammonium salt of a siderophile element.

[0020] In a specific embodiment, the catalyst of the present invention is prepared and obtained by the following steps: The raw material containing siderophile elements is dissolved or dispersed in water, and concentrated ammonia (mass concentration 25-28%) is added dropwise to cause precipitation. The heat release temperature is controlled to be less than 80°C, and the mixture is left to age for 12-24 hours. The mixture is then distilled and crystallized at a low temperature (less than 80°C) for 6-12 hours, centrifuged, and dried in an oven at 60-80°C for 12-24 hours to obtain a precursor, which is then roasted at 300-500°C for 5-24 hours under nitrogen protection, and then crushed, formed, crushed, and sieved to produce the catalyst.

[0021] In a preferred embodiment, the present invention provides a precursor of a mixture containing at least one of a hydroxide of a siderophile element and an ammonium salt of an acid of a siderophile element, the specific preparation process of which is as follows:

[0022] A mixture of concentrated ammonia and a second-class salt solution is dropped into a first-class metal salt solution to precipitate, and the temperature is controlled to be ≦80°C. The mixture is left to age for 12-24 hours, and then the precursor is obtained by distillation, crystallization, centrifugation, and drying. Finally, the catalyst is obtained by roasting. The first group metal salt solution is obtained by dissolving or dispersing at least one selected from a metal acid, a metal salt, a metal alkoxide, and a chloride of a siderophile element in water, and the second group salt solution is obtained by dissolving or dispersing an acid ammonium salt of a siderophile element in water.

[0023] Furthermore, the first group metal salt solution is obtained by dissolving or dispersing in water at least one selected from tungstic acid, sodium tungstate, tungsten chloride, molybdic acid, sodium molybdate, and molybdenum chloride, and the second group salt solution is obtained by dissolving or dispersing in water at least one selected from ammonium tungstate, ammonium paratungstate, and ammonium molybdate.

[0024] In the produced and obtained precursor, the molar ratio of the hydroxide of the siderophile element to the acid ammonium salt of the siderophile element is 1:(0.5 to 1). Preferably, the molar ratio of the hydroxide of the siderophile element to the acid ammonium salt of the siderophile element is 1:(0.7 to 1).

[0025] The catalyst precursor thus produced contains not only the hydroxide of the siderophile element but also the acid ammonium salt of the siderophile element, thereby increasing the activity of the catalyst thus produced and extending its life.

[0026] When the catalyst obtained by the above production method is applied to the reaction for producing heptafluoroisobutyronitrile by dehydration of heptafluoroisobutyronitrile, the catalyst life is 500 to 2000 hours and the space-time yield is 0.5 to 1.5 t / (m 3 Generally, when the reaction temperature is about 150 to 350°C, the catalyst life is about 1000 to 2000 hours, and when the reaction temperature is about 350 to 600°C, the catalyst life is about 500 to 1500 hours. Preferably, the catalyst life is 1000 to 2000 hours, and the space-time yield is 1.0 to 1.5 t / (m 3 cat·h).

[0027] Furthermore, once deactivated, the catalyst of the present invention can be regenerated very easily: specifically, the catalyst is regenerated by blowing air and / or oxygen at 500-800°C and purging. [Effects of the Invention]

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The catalyst produced by the present invention is used to carry out catalytic dehydration of heptafluoroisobutyramide, which is low cost, produces little waste, is environmentally friendly, has good catalytic activity, good product selectivity, good reaction reproducibility, has a long catalyst life, and is easy to activate and regenerate. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 10 is a graph showing an evaluation of catalyst life for tungsten oxide (Cat 2) in Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will now be further described with reference to specific examples, but the present invention is not limited to these specific embodiments. Those skilled in the art should understand that the present invention covers all alternatives, modifications, and equivalents that may fall within the scope of the claims.

[0032] In this embodiment, gas chromatography was performed using a Shimadzu GC-2014 analyzer and a GAS-Pro (60 m x 0.32 mm x 1.0 μm) chromatography column. The GC analysis method was as follows: detector temperature 250°C, vaporizer temperature 250°C, column temperature 60°C (5 min), 10°C / min, 85°C (3 min), 10°C / min, 250°C (4 min), carrier gas (N2) flow rate 1.05 mL / min, air flow rate 300 mL / min, hydrogen flow rate 30 mL / min, split ratio 50:1, injection volume 0.2 mL.

[0033] Manufacturing Example 1 Molybdenum chloride (1.0 eq) was slowly added to 500 mL of deionized water until a partial precipitate formed. The temperature was controlled to be below 80°C (Liquid A). Concentrated ammonia (9.0 eq, 28%) and ammonium molybdate (1.0 eq) were mixed (Liquid B). Liquid A was vigorously stirred, and Liquid B was slowly added while the temperature was controlled to be below 80°C. The mixture was left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, a mixture of molybdenum hydroxide and ammonium molybdate. The precursor was then roasted under nitrogen protection at 400°C for 6 hours, followed by milling, molding, crushing, and sieving to produce molybdenum oxide, designated Cat. 1.

[0034] Manufacturing Example 2 Tungsten chloride (1.0 eq) was slowly added to 500 mL of deionized water until a partial precipitate was formed. The temperature was controlled to be below 80°C (Liquid A). Concentrated ammonia (10.0 eq, 28%) and ammonium paratungstate were mixed (Liquid B). Liquid A was stirred vigorously, and Liquid B was slowly added while the temperature was controlled to be below 80°C. The mixture was left to age for 24 hours, crystallized at a low temperature (<50°C) for 12 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, a mixture of tungsten hydroxide and ammonium tungstate. The precursor was then roasted under nitrogen protection at 400°C for 8 hours, followed by milling, molding, crushing, and sieving to produce tungsten oxide, designated Category 2.

[0035] Manufacturing Example 3 Tin chloride hydrate (1.0 eq) is slowly added to 500 mL of deionized water until a partial precipitate gradually precipitates. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (2.5 eq, 28%) is slowly added to the reaction solution while controlling the exothermic temperature to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is tin hydroxide. The precursor is then roasted under nitrogen protection at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce tin oxide, designated as Category 3.

[0036] Production Example 4 Gallium chloride (1.0 eq) is slowly added to 500 mL of deionized water, and some precipitation occurs gradually. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (3.5 eq, 28%) is slowly added to the reaction solution, and the exothermic temperature is controlled to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is gallium hydroxide. Under nitrogen protection, the precursor is roasted at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce gallium oxide, which is designated as Category 4.

[0037] Manufacturing Example 5 Osmium chloride (1.0 eq) was slowly added to 500 mL of deionized water until a partial precipitate was formed. The exothermic temperature was controlled to be less than 80°C. Concentrated ammonia (3.5 eq, 28%) was slowly added to the reaction solution while controlling the exothermic temperature to be less than 80°C. The mixture was left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which was osmium hydroxide. The precursor was then roasted under nitrogen protection at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce osmium oxide, designated as Category 5.

[0038] Manufacturing Example 6 Iridium chloride (1.0 eq) is slowly added to 500 mL of deionized water until a partial precipitate gradually precipitates. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (4.5 eq, 28%) is slowly added to the reaction solution while controlling the exothermic temperature to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is iridium hydroxide. Under nitrogen protection, the precursor is roasted at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce iridium oxide, designated as Cat. 6.

[0039] Manufacturing Example 7 Ruthenium chloride (1.0 eq) is slowly added to 500 mL of deionized water, and some precipitation occurs gradually. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (3.5 eq, 28%) is slowly added to the reaction solution, and the exothermic temperature is controlled to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is ruthenium hydroxide. The precursor is then roasted under nitrogen protection at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce ruthenium oxide, designated as Cat. 7.

[0040] Manufacturing Example 8 Rhenium chloride (1.0 eq) is slowly added to 500 mL of deionized water until a partial precipitate gradually precipitates. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (5.5 eq, 28%) is slowly added to the reaction solution while controlling the exothermic temperature to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is rhenium hydroxide. The precursor is then roasted under nitrogen protection at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce rhenium oxide, designated as Cat 8.

[0041] Manufacturing Example 9 Titanium tetrachloride (1.0 eq) is slowly added to 500 mL of deionized water until a partial precipitate is formed. The exothermic temperature is controlled to be less than 80°C. Concentrated ammonia (5.0 eq, 28%) is slowly added to the reaction solution while controlling the exothermic temperature to be less than 80°C. The mixture is left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which is titanium hydroxide. The precursor is then roasted under nitrogen protection at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce titanium oxide, designated as Cat. 9.

[0042] Manufacturing Example 10 The procedure of this production example is the same as that of Production Example 1, except that only concentrated ammonia is used for precipitation, and ammonium molybdate is not mixed with it. The obtained precursor is molybdenum hydroxide, and the molybdenum oxide obtained after roasting, grinding, molding, crushing, and sieving is designated as Cat 10.

[0043] Comparative Manufacturing Example 1 Continuing with the catalyst manufacturing method in Patent CN109320436A, taking cobalt oxide as an example, the manufacturing process is as follows: cobalt nitrate hydrate is dissolved in water, concentrated ammonia is added dropwise to precipitate, the pH is adjusted to 7.5, and the mixture is aged for 12 hours, washed, filtered, dried in an oven at 80°C for 36 hours, and then roasted at 450°C for 8 hours under nitrogen protection to obtain cobalt oxide, designated as CatD1.

[0044] Comparative Manufacturing Example 2 Aluminum trichloride (1.0 eq) was slowly added to 500 mL of deionized water and stirred to dissolve. Concentrated ammonia (3.2 eq, 28%) was slowly added to the reaction solution, and the exothermic temperature was controlled to be less than 80°C. The mixture was left to age for 24 hours, centrifuged, and dried in an oven at 80°C for 12 hours to obtain the precursor, which was aluminum hydroxide. Under nitrogen protection, the precursor was roasted at 400°C for 8 hours, crushed, formed, crushed, and sieved to produce aluminum oxide, designated Cat D2.

[0045] Example 1 An Inconel tubular reactor having an inner diameter of 10 cm and an internal volume of 50 ml was filled with 20 ml of molybdenum oxide (Category 1) produced in Production Example 1. The preheating furnace temperature was 150°C, and circulating water at 60°C was injected into the gas-liquid separation tank jacket.

[0046] The reaction conditions are set as follows: reaction temperature: 350°C, reaction pressure: 1 bar, heptafluoroisobutyramide feed rate: 0.5 mL / min, and residence time: 6.5 s.

[0047] The reaction process involves first heating and dissolving heptafluoroisobutyronitrile, then injecting it into a preheated furnace via a high-temperature feed pump to vaporize it. The vaporized heptafluoroisobutyronitrile undergoes catalytic dehydration in a tubular reactor. The reactants coming out of the reaction tube are first separated through a gas-liquid separation tank, and the liquid in the separation tank is discharged and circulated to the preheated furnace via a bypass passage. The gas is then deeply cooled in two stages: in the first stage, water is separated at 0°C, and in the second stage, heptafluoroisobutyronitrile product is separated at -10°C and filled into a cylinder, which is not condensed and is then washed with alkali before being discharged.

[0048] Analysis of the heptafluoroisobutyronitrile product using GC reveals a product purity of 99.2% and a heptafluoroisobutyronitrile yield of 98.0%.

[0049] Example 2 The operation of this example is the same as that of Example 1, except that the tungsten oxide (Category 2) produced in Production Example 2 is filled in. Other conditions remain unchanged, and the residence time is calculated as 6.5.

[0050] Analysis of the heptafluoroisobutyronitrile product using GC reveals a product purity of 99.5% and a heptafluoroisobutyronitrile yield of 99.1%.

[0051] Under the reaction conditions of this example, catalyst life evaluation was performed on tungsten oxide (Category 2). Figure 1 shows the reaction results of a 1000-hour continuous reaction using tungsten oxide (Category 2). The reaction was performed continuously, with sampling and analysis every 24 hours, and the product was weighed. As shown in Figure 1, after 1000 hours of continuous reaction, GC analysis revealed that the purity of the heptafluoroisobutyronitrile product decreased from 99.5% to 89.5%, and the yield decreased from 99.1% to 85.0%.

[0052] Examples 3 to 10 The operations of Examples 3 to 10 were the same as those of Example 1, except that Cat 3 to Cat 10 prepared in Preparation Examples 3 to 10 were used, respectively, and the other operations remained unchanged. The heptafluoroisobutyronitrile products of each Example were analyzed using GC, and the purity and yield of the products are shown in Table 1 below.

[0053] Comparative Examples 1-2 The procedures of Comparative Examples 1 and 2 were the same as those of Example 1, except that Cat D1 to Cat D2 obtained in Comparative Preparation Examples 1 and 2 were loaded, respectively, and other procedures remained unchanged. The heptafluoroisobutyronitrile products of each Comparative Example were analyzed using GC, and the purity and yield of the products are shown in Table 1 below.

[0054] JPEG2025541647000003.jpg83170

[0055] Example 11 The operation of this example is the same as that of Example 1, except that the reaction temperature is set to 450°C, and other conditions are unchanged, and the residence time is calculated and acquired as 5.6 seconds.

[0056] Analysis of the heptafluoroisobutyronitrile product using GC reveals a product purity of 96.1% and a heptafluoroisobutyronitrile yield of 93.4%.

[0057] Example 12 The operation of this example is the same as that of Example 1, except that the heptafluoroisobutylamide feed rate is 1.0 mL / min, and other conditions are unchanged. The residence time is calculated as 3.3 s.

[0058] Analysis of the heptafluoroisobutyronitrile product using GC reveals a product purity of 90.7% and a heptafluoroisobutyronitrile yield of 88.5%.

[0059] Example 13 The operation of this example is the same as that of Example 1, except that the reaction pressure is 2 bar, and other conditions are unchanged, and the residence time is calculated and acquired as 13.0 seconds.

[0060] Analysis of the heptafluoroisobutyronitrile product using GC reveals a product purity of 97.9% and a heptafluoroisobutyronitrile yield of 95.1%.

[0061] Example 14 The reaction conditions used in this example were the same as those used in Example 16 of Patent CN109320436A. That is, an Inconel tubular reactor with an inner diameter of 10 cm and an internal volume of 50 mL was filled with 20 mL of the tungsten oxide (Category 2) prepared in Preparation Example 2.

[0062] The reaction conditions were a reaction temperature of 400°C, a reaction pressure of 0.1 MPa, and a contact time of heptafluoroisobutyramide of 10 seconds.

[0063] During the reaction process, the reactant stream coming out of the reaction tube first flows through a PTFE bottle to carry out condensation, the solids are retained at the bottom of the bottle, and then the water is removed through a drying tube, and the reactant stream enters a 200 mL small steel bottle made of 316 material to collect the gas phase product heptafluoroisobutyronitrile in the reaction system.

[0064] After 24 hours of continuous reaction, sampling was carried out every 2 hours and heptafluoroisobutyronitrile was analyzed using GC. The reaction results are shown in Table 2 below.

[0065] JPEG2025541647000004.jpg109170

[0066] Comparative Example 3 The procedure of this comparative example was the same as that of Example 14, except that Cat. D1 was used instead of Cat. 2, and other conditions were unchanged. After 24 hours of continuous reaction, samples were taken every 2 hours and the products were analyzed using GC. The reaction results are shown in Table 3 below.

[0067] JPEG2025541647000005.jpg106170

[0068] As can be seen from Table 3, after 24 hours of continuous reaction, the reaction selectivity continues to decrease. After 24 hours of reaction, the catalyst coking becomes serious, and the high-temperature (400°C) decomposition products hexafluoropropylene and heptafluoropropane coexist.

[0069] Example 15 In Example 2, the catalyst reacted for 1000 hours was regenerated by injecting air into the reactor, heating the reactor to 500°C, and burning the catalyst to remove carbon deposits and maintain the hexagonal crystal structure. The regenerated catalyst was evaluated according to the reaction conditions of Example 2, and the purity of heptafluoroisobutyronitrile was 98.1% and the yield of heptafluoroisobutyronitrile was 92.7%.

Claims

1. 1. A process for producing heptafluoroisobutyronitrile by vapor phase catalysis, comprising: The method includes a step of obtaining heptafluoroisobutyronitrile by removing one molecule of water from heptafluoroisobutyroamide gas under the action of a catalyst, wherein the catalyst is an oxide of a siderophile element, and the siderophile element includes at least one intermediate siderophile element selected from tungsten, molybdenum, tin, or gallium, or at least one highly siderophile element selected from osmium, iridium, ruthenium, rhenium, or titanium.

1. A method for producing heptafluoroisobutyronitrile using a gas phase catalyst, comprising:

2. The catalyst is an oxide of at least one of the intermediate siderophile elements tungsten, molybdenum, tin, or gallium. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 1.

3. The catalyst is molybdenum oxide and / or tungsten oxide. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 2.

4. The reaction temperature is 150-600°C, the reaction pressure is 1-3 bar, and (τ-1)s≦residence time≦(τ+1)s, where τ is calculated and obtained according to the following formula: In the formula, r is the radius of the reaction tube, h is the effective height of the reaction tube (i.e., the catalyst packing height), k is the catalyst packing factor, M=213.05 g / mol, P is the reaction pressure, v is the feed rate, ρ=1.517 g / mL, R=8.314 J / (mol·K), and T is the reaction temperature. A method for producing heptafluoroisobutyronitrile using the gas phase catalyst according to any one of claims 1 to 3.

5. The reaction temperature is 300°C to 500°C, the reaction pressure is 1 to 2 bar, and the residence time is (τ-0.1)s≦(τ+0.1)s. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 4.

6. The catalyst is produced and obtained by the following steps: Concentrated ammonia is dropped into the metal salt solution to precipitate, and the temperature is controlled to be ≦80°C. The solution is left to stand for 12-24 hours for aging. After that, the precursor is obtained by distillation, crystallization, centrifugation, and drying. Finally, the catalyst is obtained by roasting. The metal salt solution is obtained by dissolving or dispersing a raw material containing a siderophile element in water. A method for producing heptafluoroisobutyronitrile using the gas phase catalyst according to any one of claims 1 to 3.

7. The raw material containing a siderophile element is at least one selected from a metal acid, a metal acid salt, a metal alkoxide, a chloride, and an ammonium salt of an acid. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 6.

8. The precursor is at least one of a hydroxide and an ammonium salt of a siderophile element. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 7.

9. The catalyst is produced and obtained by the following steps: A mixture of concentrated ammonia and a second salt solution is dropped into a first metal salt solution to precipitate, and the temperature is controlled to be ≦80°C. The mixture is left to age for 12-24 hours, and then the precursor is obtained by distillation, crystallization, centrifugation, and drying. Finally, the catalyst is obtained by roasting. The first group metal salt solution is obtained by dissolving or dispersing in water at least one selected from metal acids, metal salts, metal alkoxides, and chlorides of siderophile elements, and the second group salt solution is obtained by dissolving or dispersing in water an ammonium salt of a siderophile element. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 6.

10. The first group metal salt solution is obtained by dissolving or dispersing in water at least one selected from tungstic acid, sodium tungstate, tungsten chloride, molybdic acid, sodium molybdate, and molybdenum chloride, and the second group salt solution is obtained by dissolving or dispersing in water at least one selected from ammonium tungstate, ammonium paratungstate, and ammonium molybdate. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 9.

11. The precursor is a mixture of at least one of a hydroxide of a siderophile element and an ammonium salt of an acid of a siderophile element. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 9 or 10.

12. The precursor is a hydroxide of a siderophile element and an ammonium salt of a siderophile element in a molar ratio of 1:(0.5-1). The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 11.

13. The catalyst life is 500 to 2000 hours, and the space-time yield is 0.5 to 1.5 t / (m ３ cat・h) A method for producing heptafluoroisobutyronitrile using the gas phase catalyst according to any one of claims 6 to 11.

14. The catalyst is regenerated after blowing air and / or oxygen at 500-800°C and purging. The method for producing heptafluoroisobutyronitrile using a gas phase catalyst according to claim 13.

Images