Method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene

Abstract

To provide a method for co-producing 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene.SOLUTION: A method comprises A1. a telomerization step and A2. a removal step. A1 is a telomerization step of subjecting monofluoromonochloromethane and trifluoroethylene to a telomerization reaction under the action of a telomerization catalyst to prepare 3-chloro-1,1,1,2-tetrafluoropropane, wherein the telomerization catalyst is selected from at least one halide of Al, Sb, Ti, Zr and Hf, and wherein the reaction employs a nonsolvent reaction, and A2 is a removal step of subjecting the 3-chloro-1,1,1,2-tetrafluoropropane to a dehydrochlorination reaction and a dehydrogenation reaction simultaneously under the action of an activated carbon supported noble metal catalyst to obtain 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, wherein the activated carbon supported noble metal catalyst is at least one of Pd / activated carbon and Pt / activated carbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to the production of 2,3,3,3-tetrafluoropropene, and more particularly to a method for producing 2,3,3,3-tetrafluoropropene by using trifluoroethylene as a raw material and undergoing a double-step reaction of telomerization and elimination (dehydrochlorination, dehydrofluorination, dehydrogenation, etc.). [Background technology]

[0002] 2,3,3,3-tetrafluoropropene has zero ODP, a GWP value of <1, a lower life cycle climate performance (LCCP) than conventional refrigerant HFC-134a, superior system refrigeration performance than HFC-134a, and the same atmospheric decomposition products as HFC-134a. It is currently considered the most promising automotive refrigerant alternative and has been accepted by several mainstream automakers. Currently, the production routes for 2,3,3,3-tetrafluoropropene include several of the following:

[0003] 1. Hexafluoropropylene pathway: The production of 2,3,3,3-tetrafluoropropene using hexafluoropropylene as a raw material is divided into four steps: (1) a hydrogenation reaction between hexafluoropropylene and hydrogen gas to produce 1,1,1,2,3,3-hexafluoropropane (HFC-236ea); (2) a dehydrofluorination reaction between HFC-236ea and catalysis to produce 1,1,1,2,3-pentafluoropropene (HFO-1225ye); (3) a hydrogenation reaction between HFO-1225ye and hydrogen gas to produce 1,1,1,2,3-pentafluoropropane (HFC-245eb); and (4) a dehydrofluorination reaction between HFC-245eb and catalysis to produce 2,3,3,3-tetrafluoropropene.

[0004] US Patent US20070179324A, Chinese Patents CN101544536A, CN102267869A, and CN102026947A, among others, disclose a method for producing 2,3,3,3-tetrafluoropropene through a quadruple-step reaction of hydrogenation, dehydrofluoridation, rehydrogenation, and re-dehydrofluoridation using hexafluoropropylene as a raw material. While this method has advantages such as a simple process and mature technology, it suffers from problems such as numerous reaction steps, the need to separate and purify multiple types of intermediate products, complex process steps, high capital investment, low reaction yield, high separation costs, and high energy consumption.

[0005] To address the shortcomings of the above-mentioned patented technology, Chinese Patent CN103449963B discloses a method for synthesizing 2,3,3,3-tetrafluoropropene by a multiple-step continuous reaction using hexafluoropropylene as a raw material, enabling continuous production by directly reacting intermediate products such as HFC-236ea, HFO-1225ye, and HFC-245eb without separation. However, not separating and purifying the intermediate products means that impurities constantly accumulate and are added to the reactants, ultimately affecting the yield of the target product, 2,3,3,3-tetrafluoropropene, and simultaneously increasing the difficulty of rectification separation of the 2,3,3,3-tetrafluoropropene product.

[0006] 2. Tetrachloropropene (TCP) pathway: Patent CN101395108B discloses a method for producing 2,3,3,3-tetrafluoropropene by a triple-step reaction using 1,1,2,3-tetrachloropropene as a raw material, the reaction steps being: (1) 1,1,2,3-tetrachloropropene and HF are subjected to a gas-phase fluorination reaction to produce 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), with a selectivity of 80-96%, and Cr2O3 and FeCl The process involves (2) an addition reaction between HCFO-1233xf and HF to produce 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), with SbCl5 as the catalyst, and (3) a gas-phase dechlorination reaction of HCFC-244bb under the action of an activated carbon catalyst to produce the target product, 2,3,3,3-tetrafluoropropene. This process has problems such as complex reaction steps, being unsuitable for industrial production, a low conversion rate, and a high reaction temperature.

[0007] U.S. Patent US20090099396 discloses a method for producing 2,3,3,3-tetrafluoropropene by a double-step reaction using 1,1,2,3-tetrachloropropene as a starting material. The reaction steps include: (1) liquid-phase fluorination of 1,1,2,3-tetrachloropropene with HF to produce 1,1,1,2,3-pentafluoropropane (HFC-245eb) using SbCl5 as a catalyst, with a TCP conversion rate of 100%, but the selectivity of HFC-245eb is only 53-59%, resulting in the generation of many by-products; and (2) liquid-phase dehydrofluorination of HFC-245eb under the action of an alkali metal hydroxide to produce the target product, 2,3,3,3-tetrafluoropropene. This process has the advantage of fewer reaction steps and lower capital investment, but the selectivity of the intermediate product HFC-245eb is low, and the separation of by-products is difficult.

[0008] III. The trifluoropropene pathway: Patent CN101979364A discloses a method for producing 2,3,3,3-tetrafluoropropene using 3,3,3-trifluoropropene as a raw material, the reaction being: (1) Addition reaction of 3,3,3-trifluoropropene and chlorine gas under photocatalysis to produce 1,2-dichloro-3,3,3-trifluoropropane, with a raw material conversion rate of 95% and a selectivity of 90%; (2) Liquid-phase dehydrochlorination reaction of 1,2-dichloro-3,3,3-trifluoropropane under the action of alkali metal hydroxide to produce 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). The process is divided into four steps: (1) generating the product, with both the conversion rate and selectivity reaching 90%; (2) adding HCFO-1233xf to HF to produce 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), using SnCl4, TiCl4, and fluorosulfonic acid as catalysts, with a raw material conversion rate of 95% and a selectivity of 90-96%; and (3) dehydrochlorinating HCFC-244bb in the liquid phase under the action of an alkali metal catalyst to produce the target product CF3CF=CH2, with a raw material conversion rate of 95% and a selectivity of 90-95%. This process has a long synthesis route, high equipment requirements for the chlorination reaction in the first step, and generates a large amount of wastewater in the dehalogenation reaction in the second step, resulting in a low overall yield and high synthesis costs.

[0009] IV. Other routes: Asahi Glass Patent WO2011162341A discloses a method for producing 2,3,3,3-tetrafluoropropene by hydrogenation reduction under the action of a palladium catalyst, using 1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya) as a raw material. However, this method makes it difficult to control the degree of hydrogenation reduction, and tends to produce intermediates such as 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd), 1-chloro-2,3,3,3-tetrafluoropropane (HCFC-244eb), and 2,3,3,3-tetrafluoropropane (HFC-254eb), as well as excessively reduced products. This results in low product selectivity, complicated post-treatment procedures, and the by-product HFC-254eb is prone to further dehydrofluorination during the alkaline washing process to produce 3,3,3-trifluoropropene (HFO-1243zf), which has a boiling point close to HFO-1234yf, further increasing the difficulty of impurity separation. While the above problems can be improved by controlling the reaction temperature of the catalyst bed and the absorption temperature of the alkaline washing, the degree of improvement is unclear, and the difficulty in controlling the process conditions is high, making it unsuitable for industrial expansion. [Overview of the project] [Problems that the invention aims to solve]

[0010] To solve the above technical problems, the present invention provides a method for producing 2,3,3,3-tetrafluoropropene by a double-step process that is simple, has mild reaction conditions, high product selectivity, and is suitable for industrial production. [Means for solving the problem]

[0011] The object of this invention is achieved by the following technical solution.

[0012] According to a first aspect, the present invention provides a method for producing 2,3,3,3-tetrafluoropropene by a double-step method, the method being A1. Telomerization step: A step of producing 3-chloro-1,1,1,2-tetrafluoropropane by subjecting monofluoromonochloromethane and trifluoroethylene to a pressurized telomerization reaction under the action of a telomerization catalyst, wherein the telomerization catalyst is a Lewis acid catalyst or a mixed catalyst of a Lewis acid catalyst and dichloromethane. A2. Dehydrochlorination step: A step of dehydrochlorinating 3-chloro-1,1,1,2-tetrafluoropropane under the catalytic action of activated carbon to obtain 2,3,3,3-tetrafluoropropene. It includes these steps.

[0013] The reaction formula for producing 2,3,3,3-tetrafluoropropene by the double-step method of the present invention is as follows.

[0014] [Chemical formula]

[0015] The Lewis acid catalyst of the present invention is at least one halide selected from Al, Sb, Ti, Zr, and Hf. Preferably, the Lewis acid catalyst is at least one selected from ZrCl4, HfCl4, TiCl4, AlCl3, AlF3, and SbF5. More preferably, the Lewis acid catalyst is ZrCl4 or HfCl4.

[0016] The telomerization reaction of monofluoromonochloromethane and trifluoroethylene as raw materials of the present invention is carried out under pressurized conditions, and a part or all of the raw material monofluoromonochloromethane forms a liquid under the reaction conditions. In addition, since the 3-chloro-1,1,1,2-tetrafluoropropane produced by the telomerization reaction is a liquid, the A1 step of the present invention preferably adopts a solvent-free reaction to reduce the separation steps of intermediates and / or products.

[0017] The telomerization catalyst of the present invention may employ a single Lewis acid catalyst or a mixed catalyst of a Lewis acid catalyst and dichloromethane. When a mixed catalyst is employed, the Lewis acid catalyst dissociates and activates monofluoromonochloromethane to form ions such as F - , CH2Cl + , Cl - , CH2F + , etc. Dichloromethane suppresses the recombination of ions such as F - , CH2Cl + , Cl - , CH2F + , etc., thereby ensuring the directional telomerization reaction between F - , CH2Cl + ions and trifluoroethylene, and obtaining the telomerization product CF3CHFCH2Cl with a high selectivity.

[0018] In a chemical reaction, the mixing ratio between raw materials, the mixing ratio between raw materials and a catalyst, the reaction temperature, the reaction time, etc. affect the reaction result. In particular, the combination of multiple variables greatly affects the reaction result.

[0019] In the telomerization step of the present invention, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:0.1 to 1:10, and more preferably, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:1 to 1:5. The usage amount of the Lewis acid catalyst is 0.01 to 50 wt% of the mass of monofluoromonochloromethane, and more preferably, the usage amount of the Lewis acid catalyst is 0.1 to 10 wt% of the mass of monofluoromonochloromethane. When a mixed catalyst of a Lewis acid catalyst and dichloromethane is employed, the molar mixing ratio of dichloromethane to monofluoromonochloromethane is 1:0.01 to 1:10, and more preferably, the molar mixing ratio of dichloromethane to monofluoromonochloromethane is 1:0.1 to 1:5.

[0020] The telomerization step of the present invention is carried out under pressurized conditions, with a reaction temperature of -30 to 100°C, a reaction pressure of 0.5 to 5.0 MPa, and a reaction time of 1 to 50 hours. More preferably, the reaction temperature is 0 to 50°C, the reaction pressure is 0.8 to 3.0 MPa, and the reaction time is 5 to 10 hours.

[0021] The hydrogen chloride removal step of the present invention is carried out under the catalytic action of activated carbon, the activated carbon being selected from fruit shell-based activated carbon, coal-based activated carbon, or wood-based activated carbon, and preferably fruit shell-based activated carbon.

[0022] The dehydrochlorination step is carried out at a reaction temperature of 200 to 500°C, preferably 300 to 350°C.

[0023] To further improve the product purity of 2,3,3,3-tetrafluoropropene and reduce the difficulty of post-processing, 3-chloro-1,1,1,2-tetrafluoropropane obtained by the telomerization step is separated by rectification and then used in the dehydrochlorination step.

[0024] According to a second aspect, the present invention provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, the co-production method is as follows: A1. Telomerization step: A step to produce 3-chloro-1,1,1,2-tetrafluoropropane by reacting monofluoromonochloromethane and trifluoroethylene under pressure with a telomerization catalyst, wherein the telomerization catalyst is a Lewis acid catalyst or a mixed catalyst of a Lewis acid catalyst and dichloromethane. A2. Desorption step: A step of simultaneously dehydrochlorinating and dehydrogenating 3-chloro-1,1,1,2-tetrafluoropropane under the action of a noble metal-supported activated carbon catalyst to obtain 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, wherein the noble metal-supported activated carbon catalyst is at least one of Pd / AC and Pt / AC.

[0025] The reaction equation for the co-production process of the present invention is as follows:

[0026] [ka]

[0027] The Lewis acid catalyst of the present invention is at least one halide selected from Al, Sb, Ti, Zr, and Hf. Preferably, the Lewis acid catalyst is at least one selected from ZrCl4, HfCl4, TiCl4, AlF3, AlCl3, and SbF5. More preferably, the Lewis acid catalyst is ZrCl4 or HfCl4.

[0028] The telomerization reaction of the starting material monofluoromonochloromethane and trifluoroethylene in this invention is carried out under pressurized conditions, and the starting material monofluoromonochloromethane partially or completely forms a liquid under the reaction conditions. In addition, since the 3-chloro-1,1,1,2-tetrafluoropropane produced by the telomerization reaction is a liquid, step A1 of this invention preferably employs a solvent-free reaction, reducing the separation step of intermediates and / or products.

[0029] The telomerization catalyst of the present invention may employ a single Lewis acid catalyst, or a mixed catalyst of a Lewis acid catalyst and dichloromethane. When a mixed catalyst is employed, the Lewis acid catalyst dissociates and activates monofluoromonochloromethane, and F - CH2Cl + Cl - CH2F + Dichloromethane forms ions such as F, and dissociates to form F - CH2Cl + Cl - CH2F + It suppresses the recombination of ions such as F - CH2Cl + A directed telomerization reaction between ions and trifluoroethylene is ensured, and the telomerization product CF3CHFCH2Cl is obtained with high selectivity.

[0030] In chemical reactions, factors such as the mixing ratio of raw materials, the mixing ratio of raw materials to catalyst, reaction temperature, and reaction time all affect the reaction outcome, and multivariate bonding, in particular, has a significant impact on the reaction result.

[0031] In the telomerization step of the present invention, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:0.1 to 1:10, and more preferably, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:1 to 1:5. The amount of Lewis acid catalyst used is 0.01 to 50 wt% of the mass of monofluoromonochloromethane, and more preferably, the amount of Lewis acid catalyst used is 0.1 to 10 wt% of the mass of monofluoromonochloromethane. When a mixed catalyst of Lewis acid catalyst and dichloromethane is used, the molar ratio of dichloromethane to monofluoromonochloromethane is 1:0.01 to 1:10, and more preferably, the molar ratio of dichloromethane to monofluoromonochloromethane is 1:0.1 to 1:5.

[0032] The telomerization step of the present invention is carried out under pressurized conditions, with a reaction temperature of -30 to 100°C, a reaction pressure of 0.5 to 5.0 MPa, and a reaction time of 1 to 50 hours. More preferably, the reaction temperature is 0 to 50°C, the reaction pressure is 0.8 to 3.0 MPa, and the reaction time is 5 to 10 hours.

[0033] In the desorption step of the present invention, under the action of a precious metal-supported activated carbon catalyst, when the raw material 3-chloro-1,1,1,2-tetrafluoropropane is adsorbed onto the activated carbon, a dehydrochlorination reaction occurs, and when the raw material 3-chloro-1,1,1,2-tetrafluoropropane is adsorbed onto the precious metal site on the activated carbon, a dehydrogenation reaction occurs, thereby simultaneously obtaining 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene.

[0034] The aforementioned precious metal-supported activated carbon catalyst can be manufactured by conventional methods, as long as the aforementioned precious metal-supported activated carbon catalyst of the present invention can be obtained. Preferably, the present invention employs an impregnation method for manufacturing. B1. Pretreatment of carrier: A step of drying activated carbon at 90-120°C for 12 hours or more, B2. Metal salt impregnation: A step of impregnating activated carbon that has been pretreated under vacuum or atmospheric pressure conditions with a soluble salt solution of Pd or Pt, B3. A step of drying the impregnated activated carbon, wherein the drying temperature is 90-120°C and the drying time is 12 hours or more. B4. A step of obtaining the noble metal-supported activated carbon catalyst by reducing the dried activated carbon with a hydrogen-nitrogen mixed gas, wherein the volume ratio of hydrogen gas in the hydrogen-nitrogen mixed gas is 5 to 50%, and the reduction temperature is 150 to 300°C.

[0035] In the aforementioned noble metal-supported activated carbon catalyst, the amount of Pd and Pt supported is 0.1 to 5.0 wt%, preferably 0.5 to 1.5 wt%.

[0036] The desorption step of the present invention is a gas-solid phase reaction, in which 3-chloro-1,1,1,2-tetrafluoropropane is vaporized and then loaded into a catalyst bed layer with nitrogen gas to carry out the desorption reaction, and the raw material volume space velocity of the desorption reaction is 50 to 300 h -1 The volume ratio of N2 / 3-chloro-1,1,1,2-tetrafluoropropane is (0.5~3.0):1, preferably (1.5~2.0):1.

[0037] The elimination step of the present invention is performed at a reaction temperature of 300 to 600°C, preferably 400 to 450°C.

[0038] The product distribution in the A2 elimination step can be controlled within a certain range by adjusting the precious metal-supported activated carbon catalyst manufacturing process, the amount of precious metal supported in the catalyst, and the reaction conditions. Generally, the A2 elimination step yields 30-90% 2,3,3,3-tetrafluoropropene and 10-50% 1-chloro-2,3,3,3-tetrafluoropropene. Preferably, the product of the elimination step contains 50-60% 2,3,3,3-tetrafluoropropene and 30-50% 1-chloro-2,3,3,3-tetrafluoropropene, with the remainder being by-products such as 1-chloro-3,3,3-trifluoropropene.

[0039] To further reduce the difficulty of post-processing, 3-chloro-1,1,1,2-tetrafluoropropane obtained in the telomerization step is separated by rectification and then used in the desorption step.

[0040] According to a third aspect, the present invention further provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, the co-production method is as follows: A1. Telomerization step: A step to produce 3-chloro-1,1,1,2-tetrafluoropropane by reacting monofluoromonochloromethane and trifluoroethylene under pressure with a telomerization catalyst, wherein the telomerization catalyst is a Lewis acid catalyst or a mixed catalyst of a Lewis acid catalyst and dichloromethane. A2. Dehalogenation step: A step of simultaneously dehydrochlorinating and dehydrofluorinating 3-chloro-1,1,1,2-tetrafluoropropane under the action of a composite dehalogenation catalyst to obtain 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, wherein the composite dehalogenation catalyst is manufactured from at least one oxide or fluoride selected from Al, Mg, or Cr and activated carbon powder.

[0041] The at least one oxide or fluoride among Al, Mg, or Cr is at least one selected from Al2O3, AlF3, MgF2, and Cr2O3, and the activated carbon powder is selected from fruit shell-based activated carbon, coal-based activated carbon, or wood-based activated carbon.

[0042] The reaction equation for the co-production process of the present invention is as follows:

[0043] [ka]

[0044] The Lewis acid catalyst of the present invention is at least one halide selected from Al, Sb, Ti, Zr, and Hf. Preferably, the Lewis acid catalyst is at least one selected from ZrCl4, HfCl4, TiCl4, AlF3, AlCl3, and SbF5. More preferably, the Lewis acid catalyst is ZrCl4 or HfCl4.

[0045] The telomerization reaction of the starting material monofluoromonochloromethane and trifluoroethylene in this invention is carried out under pressurized conditions, and the starting material monofluoromonochloromethane partially or completely forms a liquid under the reaction conditions. In addition, since the 3-chloro-1,1,1,2-tetrafluoropropane produced by the telomerization reaction is a liquid, step A1 of this invention preferably employs a solvent-free reaction, reducing the separation step of intermediates and / or products.

[0046] The telomerization catalyst of the present invention may employ a single Lewis acid catalyst, or a mixed catalyst of a Lewis acid catalyst and dichloromethane. When a mixed catalyst is employed, the Lewis acid catalyst dissociates and activates monofluoromonochloromethane, and F - CH2Cl + Cl - CH2F + Dichloromethane forms ions such as F, and dissociates to form F - CH2Cl + Cl- CH2F + It suppresses the recombination of ions such as F - CH2Cl + A directed telomerization reaction between ions and trifluoroethylene is ensured, and the telomerization product CF3CHFCH2Cl is obtained with high selectivity.

[0047] In chemical reactions, factors such as the mixing ratio of raw materials, the mixing ratio of raw materials to catalyst, reaction temperature, and reaction time all affect the reaction outcome, and multivariate bonding, in particular, has a significant impact on the reaction result.

[0048] In the telomerization step of the present invention, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:0.1 to 1:10, and more preferably, the molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:1 to 1:5. The amount of Lewis acid catalyst used is 0.01 to 50 wt% of the mass of monofluoromonochloromethane, and more preferably, the amount of Lewis acid catalyst used is 0.1 to 10 wt% of the mass of monofluoromonochloromethane. When a mixed catalyst of Lewis acid catalyst and dichloromethane is used, the molar ratio of dichloromethane to monofluoromonochloromethane is 1:0.01 to 1:10, and more preferably, the molar ratio of dichloromethane to monofluoromonochloromethane is 1:0.1 to 1:5.

[0049] The telomerization step of the present invention is carried out under pressurized conditions, with a reaction temperature of -30 to 100°C, a reaction pressure of 0.5 to 5.0 MPa, and a reaction time of 1 to 50 hours. More preferably, the reaction temperature is 0 to 50°C, the reaction pressure is 0.8 to 3.0 MPa, and the reaction time is 5 to 10 hours.

[0050] In the hydrogen-free dehalogenation step of the present invention, under the action of a composite dehalogenation catalyst, when 3-chloro-1,1,1,2-tetrafluoropropane is adsorbed onto activated carbon, a hydrogen chloride reaction occurs, and when 3-chloro-1,1,1,2-tetrafluoropropane is adsorbed onto Al2O3 and / or AlF3 and / or MgF2 and / or Cr2O3, a hydrogen fluoride reaction occurs, thereby simultaneously obtaining 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene.

[0051] The composite dehalogenation catalyst of the present invention can be manufactured by conventional methods, as long as the composite dehalogenation catalyst of the present invention can be obtained. Preferably, it is manufactured by a co-mixing method. B1. Mixing: A step in which Al2O3 and / or AlF3 and / or MgF2 and / or Cr2O3 and activated carbon powder are combined in a mass ratio of (0.01~0.25):1 and thoroughly mixed by mechanical stirring or ball milling, B2. Sieving: A step of sieving the mixed material to remove any uneven parts of the mixture, B3. Molding: The step of sending the sieved material to a tablet press and molding it into tablets, B4. The molded catalyst is dried, and the composite dehalogenation catalyst, for example, Al2O 3- The process includes the step of producing catalysts such as AC, AlF3-AC, MgF2-AC, and Cr2O3-AC.

[0052] The aforementioned B3 molding step can be performed to create shapes such as columnar or sheet-like forms, and there are no specific restrictions on the shape.

[0053] The drying process in step B4 is generally carried out at 90°C to 120°C for 12 hours or more.

[0054] In the composite dehalogenation catalyst of the present invention, when Al2O3 is co-mixed with activated carbon powder, the Al2O3 content is 1.0 to 20 wt% of the total catalyst amount; when AlF3 is co-mixed with activated carbon powder, the AlF3 content is 1.0 to 20 wt% of the total catalyst amount; when MgF2 is co-mixed with activated carbon, the MgF2 content is 1.0 to 20 wt% of the total catalyst amount; and when Cr2O3 is co-mixed with activated carbon, the Cr2O3 content is 1.0 to 20 wt% of the total catalyst amount.

[0055] The hydrogen dehalogenation step of the present invention is a gas-solid phase reaction, in which 3-chloro-1,1,1,2-tetrafluoropropane is vaporized and then loaded into a catalyst bed layer with nitrogen gas to carry out the hydrogen dehalogenation reaction, and the raw material volume space velocity of the hydrogen dehalogenation reaction is 50 to 300 h. -1 The volume ratio of N2 / 3-chloro-1,1,1,2-tetrafluoropropane is (0.5~3.0):1, preferably (1.5~2.0):1.

[0056] The reaction temperature of the hydrogen dehalogenation step of the present invention is 300 to 500°C, preferably 350 to 450°C.

[0057] The product distribution in the dehalogenation step can be controlled within a certain range by adjusting the manufacturing process of the complex dehalogenation catalyst, the content of the active ingredient in the catalyst, and the reaction conditions. Generally, the dehalogenation step yields 10-50% 2,3,3,3-tetrafluoropropene and 10-70% 1-chloro-3,3,3-trifluoropropene. Preferably, the product of the elimination step contains 20-40% 2,3,3,3-tetrafluoropropene and 30-60% 1-chloro-3,3,3-trifluoropropene, with the remainder being an unknown by-product.

[0058] To further reduce the difficulty of post-processing, the 3-chloro-1,1,1,2-tetrafluoropropane obtained in the telomerization step is separated by rectification and then used in the dehalogenation step. [Effects of the Invention]

[0059] Compared to the prior art, the beneficial effects of the present invention are as follows:

[0060] The present invention uses monofluoromonochloromethane and trifluoroethylene as raw materials and obtains 3-chloro-1,1,1,2-tetrafluoropropane by pressurized telomerization under the action of a Lewis acid catalyst or a mixed catalyst of Lewis acid catalyst and dichloromethane. It can be obtained by producing 2,3,3,3-tetrafluoropropene from 3-chloro-1,1,1,2-tetrafluoropropane under the catalytic action of activated carbon, or by simultaneously dehydrochlorinating and dehydrogenating 3-chloro-1,1,1,2-tetrafluoropropane under the catalytic action of a noble metal-supported activated carbon catalyst to produce 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, or by simultaneously dehydrochlorinating and dehydrofluorinating 3-chloro-1,1,1,2-tetrafluoropropane under the catalytic action of a complex dehalogenation catalyst to produce 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The three methods provided by the present invention for producing 2,3,3,3-tetrafluoropropene have advantages such as a simple process, mild reaction conditions, and high selectivity for telomerized products and target products, making them suitable for industrial expansion. [Modes for carrying out the invention]

[0061] The present invention will be further described below based on specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention encompasses all alternatives, improvements, and equivalents that may be included in the claims.

[0062] According to a first embodiment of the present invention, a method for producing 2,3,3,3-tetrafluoropropene by a double-step method is provided. (Example 1.1) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene by a double-step process, comprising a telomerization step and a dehydrochlorination step, specifically as follows:

[0063] 1. Telomeration step A1. An Inconel alloy autoclave with a volume of 250 mL was used as the reactor, and 3.0 g of HfCl4 and 20.0 g of dichloromethane were placed in the reaction vessels. After sealing the reaction vessels, nitrogen gas at 1.0 MPa was flowed through to replace the air inside the reaction vessels, and this was repeated three times. A2. After the air exchange in the reaction vessel is complete, 19.9 g (0.29 mol) of monofluoromonochloromethane and 24.6 g (0.30 mol) of trifluoroethylene are successively added. A3. Set the reaction temperature to 10°C, the stirring speed to 300 rpm, and the initial reaction pressure to 0.9 MPa. Gradually decrease the pressure as the reaction progresses, and set the reaction time to 10 hours. A4. After the reaction was completed, the unreacted gas-phase raw materials, trifluoroethylene and / or monofluoromonochloromethane, and small amounts of telomerization products and dichloromethane were collected. The substances in the reaction vessel were subjected to solid-liquid separation treatment such as filtration or distillation. The solid component was found to be the Lewis acid catalyst (HfCl4), and the liquid-phase substance was found to be dichloromethane and telomerization products. By rectification separation, 3-chloro-1,1,1,2-tetrafluoropropane with a purity of 99.9% was obtained and used in the dehydrochlorination reaction.

[0064] Unreacted gaseous raw materials and separated Lewis acid catalyst can be returned to the telomerization step and reused.

[0065] Analysis of the gas and liquid phase substances by gas chromatography revealed that the conversion rate of monofluoromonochloromethane was 76.5%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 81.2%, the main byproduct was 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.3%, and there were also small amounts of other byproducts.

[0066] 2. Dehydrochlorination step B1. An Inconel alloy reaction tube with an inner diameter of 19 mm and a length of 800 mm is used as a fixed-bed reactor. Coconut shell type activated carbon with a volume of 20 mL and a particle size of 10-20 mesh is packed into the middle of the fixed-bed reactor, connected to the reaction line, and purged by flowing nitrogen gas at a nitrogen gas flow rate of 100 mL / min. B2. Set the reaction temperature to 350°C and the heating rate to 5°C / min, and start heating the reactor. B3. After the catalyst bed reaches the reaction temperature, the nitrogen gas flow rate is adjusted to 20 mL / min, and at the same time, 99.9% pure 3-chloro-1,1,1,2-tetrafluoropropane is continuously flowed into the fixed-bed reactor at a rate of 5.0 g / h to start the reaction. B4. Online GC and GC / MS analysis of the gas mixture effluent from the reactor revealed a conversion rate of 99.6% for 3-chloro-1,1,1,2-tetrafluoropropane and a selectivity of 99.3% for the product, 2,3,3,3-tetrafluoropropene. (Example 1.2) This example provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.1, except that in the telomerization step, ZrCl4 is used instead of HfCl4, with a usage amount of 4.0 g, the amount of monofluoromonochloromethane used is increased to 39.7 g (0.58 mol), and the amount of trifluoroethylene used is increased to 71.3 g (0.87 mol). All other conditions remain unchanged.

[0067] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.0% for monofluoromonochloromethane, a selectivity of 89.9% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 5.3%, and small amounts of other byproducts. (Example 1.3) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.2, except that in the telomerization step, dichloromethane is not used, the amount of trifluoroethylene used is increased to 95.1 g (1.16 mol), the reaction temperature is increased to 30°C, and the initial reaction pressure is increased to 1.5 MPa, with no other conditions changed.

[0068] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.5% for monofluoromonochloromethane, a selectivity of 88.1% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 4.1%, and small amounts of other byproducts. (Example 1.4) This example provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.2, except that in the telomerization step, AlCl3 is used instead of ZrCl4, the amount used remains the same at 4.0 g, dichloromethane is not used, and the amount of trifluoroethylene used is reduced to 52.5 g (0.64 mol). All other conditions remain unchanged.

[0069] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.6% for monofluoromonochloromethane, a selectivity of 75.5% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.9%, and small amounts of other byproducts. (Example 1.5) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.1, except that in step A2 of the telomerization step, monofluoromonochloromethane and trifluoroethylene are successively flowed through the autoclave, and then high-purity high-pressure nitrogen gas is used to pressurize the autoclave, increasing the pressure inside the autoclave from 0.9 MPa to 3.0 MPa. All other conditions remain unchanged.

[0070] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.8% for monofluoromonochloromethane, a selectivity of 88.6% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 7.6%, and small amounts of other byproducts. (Example 1.6) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene, and the operation is the same as in Example 1.1, except that in the dehydrochlorination step, 10-20 mesh coal-based activated carbon is used instead of coconut shell-based activated carbon.

[0071] Chromatographic analysis of the dehydrochlorination products revealed a conversion rate of 99.2% to 3-chloro-1,1,1,2-tetrafluoropropane, and a selectivity of 95.1% for the product, 2,3,3,3-tetrafluoropropene. (Example 1.7) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.1, except that the reaction temperature is reduced to 300°C in the dehydrochlorination step.

[0072] Chromatographic analysis of the dehydrochlorination revealed a conversion rate of 75.8% to 3-chloro-1,1,1,2-tetrafluoropropane and a selectivity of 99.2% for the product, 2,3,3,3-tetrafluoropropene. (Example 1.8) This embodiment provides a method for producing 2,3,3,3-tetrafluoropropene, the operation being the same as in Example 1.1, except that the reaction temperature is reduced to 320°C in the dehydrochlorination step.

[0073] Chromatographic analysis of the dehydrochlorination products revealed a conversion rate of 86.9% to 3-chloro-1,1,1,2-tetrafluoropropane and a selectivity of 99.1% for the product 2,3,3,3-tetrafluoropropene. (Comparative Example 1.1) This comparative example provides a method for producing 2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 1.1, except that trichloromethane is used instead of dichloromethane, and the amount used is 20.0 g. All other conditions remain unchanged.

[0074] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 86.9%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 46.2%, and a large amount of dichloromethane, a disproportionation product of monofluoromonochloromethane, was produced with a selectivity of 40.3%, along with small amounts of other telomerization byproducts. (Comparative Example 1.2) This comparative example provides a method for producing 2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 1.1, except that ZnCl2 is used instead of HfCl4, and the amount used is 3.0 g. All other conditions remain unchanged.

[0075] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 20.8%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not formed. (Comparative Example 1.3) This comparative example provides a method for producing 2,3,3,3-tetrafluoropropene, and the procedure is the same as in Example 1.1, except that HfCl4 and dichloromethane are not added; all other conditions remain unchanged.

[0076] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 7.7%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not produced. Instead, only dichloromethane, a disproportionation product of monofluoromonochloromethane, was formed.

[0077] According to a second embodiment of the present invention, a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene is provided. (Manufacturing Example 2.1) 6.0 mL of chloropalladium acid solution (concentration 0.033 g Pd / mL) was uniformly diluted with 80.0 mL of distilled water. This impregnation solution was added to 20.0 g of activated carbon that had been pre-treated (dried at 120°C for 12 hours), impregnated for 12 hours or more, and then dried at 120°C for 12 hours to obtain a 1% wt. Pd / AC catalyst labeled cat2.1. (Manufacturing Example 2.2) 9.2 mL of chloropalladium acid solution (concentration 0.033 g Pd / mL) was uniformly diluted with 80.0 mL of distilled water. This impregnation solution was added to 20.0 g of activated carbon that had been pre-treated (dried at 120°C for 12 hours), impregnated for 12 hours or more, and then dried at 120°C for 12 hours to obtain a 1.5 wt.% Pd / AC catalyst labeled cat2.2. (Manufacturing Example 2.3) 0.35 g of PtCl4 was dissolved in 80.0 mL of distilled water, and the above impregnation solution was added to 20.0 g of activated carbon that had been pre-treated (dried at 120°C for 12 hours). The impregnation was allowed for 12 hours or more, and then dried at 120°C for 12 hours to obtain a 1 wt.% Pt / AC catalyst labeled cat2.3. (Manufacturing Example 2.4) 0.52 g of PtCl4 was dissolved in 80.0 mL of distilled water, and the above impregnation solution was added to 20.0 g of activated carbon that had been pre-treated (dried at 120°C for 12 hours). The impregnation was allowed for 12 hours or more, and then dried at 120°C for 12 hours to obtain a 1.5 wt.% Pt / AC catalyst labeled cat2.4. (Example 2.1) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, comprising a telomerization step and an elimination step, specifically as follows.

[0078] 1. Telomeration step A1. An Inconel alloy autoclave with a volume of 250 mL was used as the reactor, and 3.0 g of HfCl4 and 20.0 g of dichloromethane were placed in the reaction vessels. After sealing the reaction vessels, nitrogen gas at 1.0 MPa or higher was flowed through them to replace the air inside the vessels, and this was repeated three times. A2. After the air exchange in the reaction vessel is complete, 19.9 g (0.29 mol) of monofluoromonochloromethane and 24.6 g (0.30 mol) of trifluoroethylene are successively added. A3. Set the reaction temperature to 10°C, the stirring speed to 300 rpm, and the initial reaction pressure to 0.9 MPa. Gradually decrease the pressure as the reaction progresses, and set the reaction time to 10 hours. A4. After the reaction was completed, the unreacted gas-phase raw materials, trifluoroethylene and / or monofluoromonochloromethane, and small amounts of telomerization products and dichloromethane were collected. The substances in the reaction vessel were subjected to solid-liquid separation treatment such as filtration or distillation. The solid component was found to be the Lewis acid catalyst (HfCl4), and the liquid-phase substance was found to be dichloromethane and telomerization products. By rectification separation, 3-chloro-1,1,1,2-tetrafluoropropane with a purity of 99.9% was obtained and used in the elimination step.

[0079] Unreacted gaseous raw materials and separated Lewis acid catalyst can be returned to the telomerization step and reused.

[0080] Analysis of the gas and liquid phase substances by gas chromatography revealed that the conversion rate of monofluoromonochloromethane was 76.5%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 81.2%, the main byproduct was 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.3%, and there were also small amounts of other byproducts.

[0081] 2. Detachment Step B1. An Inconel alloy reaction tube with an inner diameter of 19 mm and a length of 800 mm is used as a fixed-bed reactor. 20 mL of cat2.1 is filled into the middle of the fixed-bed reactor, connected to the reaction line, and purged by flowing nitrogen gas at a nitrogen gas flow rate of 100 mL / min. B2. Set the reaction temperature to 450°C and the heating rate to 5°C / min, and start heating the reactor. B3. After the catalyst bed reaches the reaction temperature, the nitrogen gas flow rate is adjusted to 20 mL / min, and simultaneously, a peristaltic pump is used to continuously supply 99.9% pure 3-chloro-1,1,1,2-tetrafluoropropane to the fixed-bed reactor at a rate of 5.0 g / h to start the reaction. B4. The gas mixture released from the reactor was kept warm and analyzed online by GC and GC / MS. The conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 96.8%, the content of 2,3,3,3-tetrafluoropropene in the product was 56.3%, and the content of 1-chloro-2,3,3,3-tetrafluoropropene was 31.4%. (Example 2.2) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The operation is the same as in Example 2.1, except that in the telomerization step, ZrCl4 is used instead of HfCl4, with a usage amount of 4.0 g, the amount of monofluoromonochloromethane used is increased to 39.7 g (0.58 mol), and the amount of trifluoroethylene used is increased to 71.3 g (0.87 mol). All other conditions remain unchanged.

[0082] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.0% for monofluoromonochloromethane, a selectivity of 89.9% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 5.3%, and small amounts of other byproducts. (Example 2.3) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The operation is the same as in Example 2.2, except that in the telomerization step, dichloromethane is not used, the amount of trifluoroethylene used is increased to 95.1 g (1.16 mol), the reaction temperature is increased to 30°C, and the initial reaction pressure is increased to 1.5 MPa. All other conditions remain unchanged.

[0083] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.5% for monofluoromonochloromethane, a selectivity of 88.1% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 4.1%, and small amounts of other byproducts. (Example 2.4) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The operation is the same as in Example 2.2, except that in the telomerization step, AlCl3 is used instead of ZrCl4, the amount used remains the same at 4g, dichloromethane is not used, and the amount of trifluoroethylene used is reduced to 52.5g (0.64mol). All other conditions remain unchanged.

[0084] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.6% for monofluoromonochloromethane, a selectivity of 75.5% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.9%, and small amounts of other byproducts. (Example 2.5) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The operation is the same as in Example 2.1, except that in step A2 of the telomerization step, monofluoromonochloromethane and trifluoroethylene are flowed into the autoclave beforehand, and the autoclave is pressurized using high-purity high-pressure nitrogen gas to increase the pressure inside the autoclave from 0.9 MPa to 3.0 MPa. All other conditions remain unchanged.

[0085] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.8% for monofluoromonochloromethane, a selectivity of 88.6% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 7.6%, and small amounts of other byproducts. (Example 2.6) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, and the operation is the same as in Example 2.1, except that cat2.3 is used instead of cat2.1 in the elimination step.

[0086] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 89.3%, the content of 2,3,3,3-tetrafluoropropene in the product was 90.3%, and the content of 1-chloro-2,3,3,3-tetrafluoropropene was 7.7%. (Example 2.7) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, the operation being the same as in Example 2.1, except that the amount of cat2.1 used in the elimination step is increased to 40 mL.

[0087] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 95.8%, the content of 2,3,3,3-tetrafluoropropene in the product was 65.7%, and the content of 1-chloro-2,3,3,3-tetrafluoropropene was 26.8%. (Example 2.8) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, and the operation is the same as in Example 2.1, except that cat2.2 is used instead of cat2.1 in the elimination step.

[0088] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 70.1%, the content of 2,3,3,3-tetrafluoropropene in the product was 39.2%, and the content of 1-chloro-2,3,3,3-tetrafluoropropene was 28.5%. (Example 2.9) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, the operation being the same as in Example 2.1, except that the reaction temperature in the elimination step is 400°C.

[0089] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 96.7%, the content of 2,3,3,3-tetrafluoropropene in the product was 85.2%, and the content of 1-chloro-2,3,3,3-tetrafluoropropene was 10.3%. (Comparative Example 2.1) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 2.1, except that trichloromethane is used instead of dichloromethane, and the amount used is 20.0 g. All other conditions remain unchanged.

[0090] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 86.9%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 46.2%, and a large amount of dichloromethane, a disproportionation product of monofluoromonochloromethane, was produced with a selectivity of 40.3%, along with small amounts of other telomerization byproducts. (Comparative Example 2.2) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 2.1, except that ZnCl2 is used instead of HfCl4, and the amount used is 3.0 g. All other conditions remain unchanged.

[0091] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 20.8%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not formed. (Comparative Example 2.3) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 2.1, except that HfCl4 and dichloromethane are not added; all other conditions remain unchanged.

[0092] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 7.7%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not produced. Instead, only dichloromethane, a disproportionation product of monofluoromonochloromethane, was formed. (Comparative Example 2.4) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The operation is the same as in Example 2.1, except that in the desorption step, pre-treated activated carbon (dried at 120°C for 12 hours) is used instead of cat2.1. All other conditions remain unchanged.

[0093] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 99.7%, and the content of 2,3,3,3-tetrafluoropropene in the product was 99.0%, meaning that 1-chloro-2,3,3,3-tetrafluoropropene was not produced. (Comparative Example 2.5) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene. The procedure is the same as in Example 2.1, except that Al2O3 is used instead of cat2.1; all other conditions remain unchanged.

[0094] Chromatographic analysis of the elimination reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 50.1%, the content of 2,3,3,3-tetrafluoropropene in the product was 3.1%, and the content of 1-chloro-3,3,3-trifluoropropene was 62.2%, with no 1-chloro-2,3,3,3-tetrafluoropropene being produced.

[0095] According to a third embodiment of the present invention, a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene is provided. (Manufacturing Example 3.1) This manufacturing example describes the production of a copolymer catalyst, Cr2O3-AC, of ​​Cr2O3 and activated carbon powder. The manufacturing steps are as follows: The process involves blending S1.Cr2O3 and coconut shell-based activated carbon powder in a mass ratio of 1 / 9, and then placing the blended materials in a ball mill and mixing them in a ball mill to uniformly disperse each component. S2. The mixed substances are sieved to remove any uneven parts of the mixture. S3. The sieved material is sent to a tablet press and compressed into tablets to produce a columnar catalyst. S4. The process includes drying the molded catalyst at 120°C for 12 hours to produce a Cr2O3-AC catalyst labeled cat3.1. (Manufacturing Example 3.2) The procedure in this manufacturing example is the same as in manufacturing example 3.1, except that AlF3 is used instead of Cr2O3, and an AlF3-AC catalyst labeled cat3.2 is manufactured to obtain it. (Manufacturing Example 3.3) The procedure in this manufacturing example is the same as in manufacturing example 3.1, except that the mass ratio of Cr2O3 to activated carbon is changed to 1 / 4, and a Cr2O3-AC catalyst labeled cat3.3 is produced. (Example 3.1) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, comprising a telomerization step and a dehydrohalogenation step, specifically as follows.

[0096] 1. Telomeration step A1. An Inconel alloy autoclave with a volume of 250 mL was used as the reactor, and 3.0 g of HfCl4 and 20.0 g of dichloromethane were placed in the reaction vessels. After sealing the reaction vessels, nitrogen gas at 1.0 MPa or higher was flowed through them to replace the air inside the vessels, and this was repeated three times. A2. After the air exchange in the reaction vessel is complete, 19.9 g (0.29 mol) of monofluoromonochloromethane and 24.6 g (0.30 mol) of trifluoroethylene are successively added. A3. Set the reaction temperature to 10°C, the stirring speed to 300 rpm, and the initial reaction pressure to 0.9 MPa. Gradually decrease the pressure as the reaction progresses, and set the reaction time to 10 hours. A4. After the reaction was completed, the unreacted gas-phase raw materials, trifluoroethylene and / or monofluoromonochloromethane, and small amounts of telomerization products and dichloromethane were collected. The substances in the reaction vessel were subjected to solid-liquid separation treatment such as filtration or distillation. The solid component was found to be the Lewis acid catalyst (HfCl4), and the liquid-phase substance was found to be dichloromethane and telomerization products. By rectification separation, 3-chloro-1,1,1,2-tetrafluoropropane with a purity of 99.9% was obtained and used in the dehalogenation step.

[0097] Unreacted gaseous raw materials and separated Lewis acid catalyst can be returned to the telomerization step and reused.

[0098] Analysis of the gas and liquid phase substances by gas chromatography revealed that the conversion rate of monofluoromonochloromethane was 76.5%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 81.2%, the main byproduct was 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.3%, and there were also small amounts of other byproducts.

[0099] 2. Dehalogenation step B1. An Inconel alloy reaction tube with an inner diameter of 19 mm and a length of 800 mm is used as a fixed-bed reactor. 20 mL of CAT3.1 is filled into the middle of the fixed-bed reactor, connected to the reaction line, and purged by flowing nitrogen gas at a nitrogen gas flow rate of 100 mL / min. B2. Set the reaction temperature to 350°C and the heating rate to 5°C / min, and start heating the reactor. B3. After the catalyst bed reaches the reaction temperature, the nitrogen gas flow rate is adjusted to 20 mL / min, and at the same time, 99.9% pure 3-chloro-1,1,1,2-tetrafluoropropane is continuously flowed into the fixed-bed reactor at a rate of 5.0 g / h to start the reaction. B4. The gas mixture discharged from the reactor was kept warm and analyzed online by GC and GC / MS. The conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane reached 88.7%, the content of 2,3,3,3-tetrafluoropropene in the product reached 24.1%, and the content of 1-chloro-3,3,3-trifluoropropene reached 58.7%. (Example 3.2) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.1, except that in the telomerization step, ZrCl4 is used instead of HfCl4, with a usage amount of 4.0 g, the amount of monofluoromonochloromethane used is increased to 39.7 g (0.58 mol), and the amount of trifluoroethylene used is increased to 71.3 g (0.87 mol). All other conditions remain unchanged.

[0100] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.0% for monofluoromonochloromethane, a selectivity of 89.9% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 5.3%, and small amounts of other byproducts. (Example 3.3) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.2, except that dichloromethane is not used in the telomerization step, the amount of trifluoroethylene used is increased to 95.1 g (1.16 mol), the reaction temperature is increased to 30°C, and the initial reaction pressure is increased to 1.5 MPa. All other conditions remain unchanged.

[0101] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.5% for monofluoromonochloromethane, a selectivity of 88.1% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 4.1%, and small amounts of other byproducts. (Example 3.4) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.2, except that in the telomerization step, AlCl3 is used instead of ZrCl4, the amount used remains the same at 4.0 g, dichloromethane is not used, and the amount of trifluoroethylene used is reduced to 52.5 g (0.64 mol). All other conditions remain unchanged.

[0102] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.6% for monofluoromonochloromethane, a selectivity of 75.5% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 15.9%, and small amounts of other byproducts. (Example 3.5) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.1, except that in step A2 of the telomerization step, monofluoromonochloromethane and trifluoroethylene are sequentially flowed into the autoclave, and then high-purity, high-pressure nitrogen gas is used to pressurize the autoclave, increasing the pressure inside the autoclave from 0.9 MPa to 3.0 MPa. All other conditions remain unchanged.

[0103] Gas chromatography analysis of the gas and liquid phase substances in the telomerization step revealed a conversion rate of 99.8% for monofluoromonochloromethane, a selectivity of 88.6% for 3-chloro-1,1,1,2-tetrafluoropropane, the main byproduct being 1-chloro-1,1,2,3-tetrafluoropropane with a selectivity of 7.6%, and small amounts of other byproducts. (Example 3.6) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, and the operation is the same as in Example 3.1, except that in the dehalogenation step, cat3.2 is used instead of cat3.1.

[0104] Chromatographic analysis of the dehalogenation reaction product revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 92.9%, the content of 2,3,3,3-tetrafluoropropene in the product was 20.3%, and the content of 1-chloro-3,3,3-trifluoropropene was 58.7%. (Example 3.7) This embodiment provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, and the operation is the same as in Example 3.1, except that the amount of cat3.1 used in the dehalogenation step is increased to 40 mL.

[0105] Chromatographic analysis of the dehalogenation reaction product revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane exceeded 95.9%, with 2,3,3,3-tetrafluoropropene content at 16.1% and 1-chloro-3,3,3-trifluoropropene content at 44.6%. (Example 3.8) This example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, the operation being the same as in Example 3.1, except that the reaction temperature in the dehalogenation step is 450°C.

[0106] Chromatographic analysis of the dehalogenation reaction product revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 98.3%, the content of 2,3,3,3-tetrafluoropropene in the product was 15.9%, and the content of 1-chloro-3,3,3-trifluoropropene was 60.0%. (Comparative Example 3.1) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The procedure is the same as in Example 3.1, except that trichloromethane is used instead of dichloromethane, and the amount used is 20 g. All other conditions remain unchanged.

[0107] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 86.9%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 46.1%, and a large amount of dichloromethane, a disproportionation product of monofluoromonochloromethane, was produced with a selectivity of 40.3%, along with small amounts of other telomerization byproducts. (Comparative Example 3.2) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The procedure is the same as in Example 3.1, except that ZnCl2 is used instead of HfCl4, and the amount used is 3.0 g. All other conditions remain unchanged.

[0108] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 20.8%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not formed. (Comparative Example 3.3) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The procedure is the same as in Example 3.1, except that HfCl4 and dichloromethane are not added; all other conditions remain unchanged.

[0109] Chromatographic analysis of the material after the telomerization step reaction revealed that the conversion rate of monofluoromonochloromethane was 7.6%, and the target product, 3-chloro-1,1,1,2-tetrafluoropropane, was not produced. Only a small amount of dichloromethane, a disproportionation product of monofluoromonochloromethane, was formed. (Comparative Example 3.4) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.1, except that in the dehalogenation step, pre-treated (dried at 120°C for 12 hours) coconut shell-based activated carbon is used instead of cat3.1. All other conditions remain unchanged.

[0110] Chromatographic analysis of the dehalogenation reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane exceeded 99.7%, the content of 2,3,3,3-tetrafluoropropene in the product was 99.0%, and 1-chloro-3,3,3-trifluoropropene was not produced. (Comparative Example 3.5) This comparative example provides a method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene. The operation is the same as in Example 3.1, except that a Pd / AC catalyst (with a Pd load of 1 wt%) is used instead of cat3.1. All other conditions remain unchanged.

[0111] Chromatographic analysis of the dehalogenation reaction products revealed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 83.5%, the content of 2,3,3,3-tetrafluoropropene in the product was 96.4%, the content of 1-chloro-2,3,3,3-tetrafluoropropene was 1.3%, and 1-chloro-3,3,3-trifluoropropene was not produced.

Claims

1. A method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, A1. Telomeration step: A step to produce 3-chloro-1,1,1,2-tetrafluoropropane by reacting monofluoromonochloromethane and trifluoroethylene under pressure with a telomeration catalyst, wherein the telomeration catalyst is a Lewis acid catalyst or a mixed catalyst of a Lewis acid catalyst and dichloromethane, and the Lewis acid catalyst is at least one halide selected from Al, Sb, Ti, Zr, and Hf, and the A1. telomeration step employs a solvent-free reaction, A2. Desorption step: A step of simultaneously dehydrochlorinating and dehydrogenating 3-chloro-1,1,1,2-tetrafluoropropane under the action of a noble metal-supported activated carbon catalyst to obtain 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, wherein the noble metal-supported activated carbon catalyst is at least one of Pd / AC and Pt / AC. A method for the co-production of 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene, characterized in that the amount of Pd and Pt supported in the precious metal-supported activated carbon catalyst is 0.1 to 5.0 wt%, and 30 to 90% of 2,3,3,3-tetrafluoropropene and 10 to 50% of 1-chloro-2,3,3,3-tetrafluoropropene are obtained by the A2 elimination step.

2. The Lewis acid catalyst is ZrCl ４ , HfCl ４ TiCl ４ AlF ３ AlCl ３ SbF ５ A method for co-producing 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene according to feature 1, wherein at least one is selected from among the following.

3. The molar ratio of monofluoromonochloromethane to trifluoroethylene is 1:0.1 to 1:

10. The Lewis acid catalyst is present in an amount of 0.01 wt% to 50 wt% of the mass of monofluoromonochloromethane. The molar ratio of dichloromethane to monofluoromonochloromethane is 1:0.01 to 1:

10. The method for co-producing 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene according to claim 1, characterized in that the pressurized telomerization reaction is carried out at a temperature of -30 to 100°C and a pressure of 0.5 to 5.0 MPa, and the reaction time is 1 to 50 hours.

4. The aforementioned precious metal-supported activated carbon catalyst is manufactured by an impregnation method. B1. Pre-treatment of carrier: A step of drying activated carbon at 90-120°C for 12 hours or more, B2. Metal salt impregnation: A step of impregnating activated carbon that has been pretreated under vacuum or atmospheric pressure conditions with a soluble salt solution of Pd or Pt, B3. The activated carbon after impregnation is dried, with a drying temperature of 90-120°C and a drying time of 12 hours or more. B4. A method for co-producing 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene according to claim 1, characterized in that a dried activated carbon is reduced with a hydrogen-nitrogen mixed gas to obtain the noble metal-supported activated carbon catalyst, wherein the volume ratio of hydrogen gas in the hydrogen-nitrogen mixed gas is 5 to 50%, and the reduction temperature is 150 to 300°C.

5. 3-chloro-1,1,1,2-tetrafluoropropane is vaporized and then loaded into the catalyst bed layer with nitrogen gas to carry out the desorption reaction, with a raw material volume space velocity of 50-300 h⁻¹. －１ And N ２ The volume ratio of / 3-chloro-1,1,1,2-tetrafluoropropane is (0.5 to 3.0):1, The aforementioned elimination step is performed at a reaction temperature of 300 to 600°C. The method for producing both 2,3,3,3-tetrafluoropropene and 1-chloro-2,3,3,3-tetrafluoropropene according to claim 1, characterized in that 3-chloro-1,1,1,2-tetrafluoropropane obtained in the telomerization step is used in the elimination step after being separated by rectification.

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