Catalyst for preparing 2-chloro-3, 3, 3-trifluoropropene through gas phase fluorination, method and application

Abstract

The invention discloses a catalyst for preparing 2-chloro-3, 3, 3-trifluoropropene through gas phase fluorination, a method and application, and solves the problems of serious carbon deposition in fluorine-chlorine exchange reaction and short service life of the catalyst. The preparation method of the catalyst comprises the following steps: introducing an assistant A and an assistant C into a chromium salt solution in a reaction container in the presence of a precipitant by adopting a co-dripping feeding mode, keeping the solution in the container to be alkaline, and generating hydroxide crystals in the cooled container; crushing the hydroxide precursor and dipping the hydroxide precursor in an auxiliary agent B solution so as to introduce an auxiliary agent B; wherein the auxiliary agent A is at least one of Fe, Co, Ni, Cu and Zn salts, the auxiliary agent B is at least one of Zr, Ce, Sn, Ti, Mn, W and V salts, and the auxiliary agent C is at least one of Mg, K, Na, Y, Hf, La, Sm and B salts.

Description

Technical Field

[0001] The invention belongs to fluorine chemical technology, and specifically relates to a preparation method and application of a catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination. Background Art

[0002] 2-Chloro-3,3,3-trifluoropropene is one of the important intermediates for the preparation of the fourth-generation refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf), and can also be used as a monomer for a variety of polymers. The difficulty in synthesizing 2-chloro-3,3,3-trifluoropropene is to develop a catalyst for the fluorine-chlorine exchange of polychlorinated alkanes with a long life and mild reaction conditions.

[0003] Patent document 1, CN103946196A, points out that high temperature during the fluorination of 1,1,2,3-tetrachloropropylene (HCO-1230xa) to generate 2-chloro-3,3,3-trifluoropropylene (HCFO-1233xf) will cause catalyst instability. The experimental fluorination catalyst is fluorinated Cr2O3, and the reaction selectivity is 93% at 200°C. In addition, patent document CN104961623A points out that when the water content is controlled at an extremely low concentration, the reduction of catalytic activity can be suppressed.

[0004] Patent Documents 2 and 3, US20090030244A1, and CN101874009A use 1,1,2,3-tetrachloropropylene (HCO-1230xa) as a reactant, use Cr2O3 as a catalyst, and add a stabilizer to improve the selectivity and life of the catalyst. However, the addition of the stabilizer affects the subsequent product separation.

[0005] Patent document 4, WO2009003084A1 reports the fluorination of 1230xa in a liquid phase reactor without a catalyst, which has a long reaction time and high pressure, affecting the subsequent large-scale production.

[0006] Compared with Patent 1, the catalyst disclosed in CN1680029A converts antimony halide (SbF n Cl 5-n ) is loaded on calcium fluoride, but the catalyst has low activity and poor thermal stability.

[0007] Comparative Patent 2 and Comparative Patent 3, CN102405202A and CN104707608B respectively reported the use of nickel beads and Fe-Mg composite oxide as catalysts to avoid the use of Cr, but the reaction needs to be reacted at a temperature of 260°C or even higher. The fluorine-chlorine exchange reaction itself is an exothermic reaction, and high temperature promotes the decomposition and carbon deposition of polychlorinated alkanes. If the heat is not dissipated in time, it is easy to accelerate the carbonization of the raw materials and cause pipeline blockage.

[0008] Compared with Patent 4, in CN101961658B, the conversion rate of 240ab is 92%, the selectivity for HCFO-1233xf is 91%, and a large amount of high-boiling by-products affects the subsequent separation. Summary of the invention

[0009] In view of the defects of the prior art, the present invention provides a method for preparing a catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination and its application, which solves the problems of severe carbon deposition and short catalyst life in the fluorine-chlorine exchange reaction.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0011] First, a method for preparing a catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination is provided, comprising the following steps:

[0012] In a reaction container, the chromium salt solution is introduced into the auxiliary agent A and the auxiliary agent C in the presence of a precipitant by a co-dropping method, and the solution inside the container is kept alkaline, and hydroxide crystals are generated in the container at a reduced temperature;

[0013] The hydroxide crystals are crushed and immersed in a solution of the additive B, thereby introducing the additive B;

[0014] Among them, the auxiliary agent A is at least one of Fe, Co, Ni, Cu, and Zn salts, the auxiliary agent B is at least one of Zr, Ce, Sn, Ti, Mn, W, and V salts, and the auxiliary agent C is at least one of Mg, K, Na, Y, Hf, La, Sm, and B salts.

[0015] Preferably, the co-dropping method includes dropping the auxiliary agent A, the aqueous solution of the chromium salt and the precipitant solution into the aqueous solution of the auxiliary agent C.

[0016] Preferably, the co-dropping method further comprises continuously adding an aqueous solution of the auxiliary agent C; and / or, during the co-dropping method, maintaining the pH of the solution inside the container between 7-11.

[0017] Preferably, during the co-dropping process, the temperature of the container is simultaneously lowered and the temperature difference between the center of the solution and the container wall is maintained between 10-30°C; wherein the solution temperature is maintained at 20-40°C and the inner wall of the container is maintained at 0-25°C.

[0018] Preferably, the chromium salt is at least one of nitrate, acetate, and chloride; and / or, the auxiliary agent A and auxiliary agent C are at least one of nitrate, acetate, chloride, oxychlorate, phosphate, isopropoxide, and citrate, and the components of auxiliary agent A and auxiliary agent C are different; and / or, the auxiliary agent B is at least one of nitrate, acetate, and chloride; and / or, the solvent of the auxiliary agent B is at least one of water, ethanol, methanol, acetone, ethylenediamine, ether, and ammonia water; and / or, the precipitant solution is an aqueous solution of at least one of sodium carbonate, sodium hydroxide, potassium hydroxide, ammonia, urea, and ammonium bicarbonate.

[0019] Preferably, the molar ratio of the auxiliary agent A to the aqueous solution of the chromium salt is auxiliary agent A 1.0: chromium salt 4.9-20.0: water 50-500; and / or, the concentration of the aqueous solution of the auxiliary agent C is 0.001-0.5 mol / L; and / or, the mass ratio of auxiliary agent B to solvent in the auxiliary agent B solution is auxiliary agent B 1.0: solvent 20-400; and / or, the concentration of the precipitant solution is 0.1-8 mol / L.

[0020] Preferably, the method further comprises the steps of removing the solvent after impregnation, granulating and calcining; wherein the granulating method is to add 0.1-5wt% graphite and pressurize the granules; the calcining method is to calcine at 400-800°C under nitrogen for 3-72h, then cool down to 250°C, heat up to 350°C, and gradually introduce HF during the heating process until pure HF gas is fluorinated.

[0021] Secondly, the present invention also provides a catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination, which is prepared by the above method.

[0022] Preferably, the molar content of Cr in the catalyst is 40-85%; and / or, the molar content of the auxiliary agent A is 5-20%; and / or, the molar content of the auxiliary agent B is 0.2-12%; and / or, the molar content of the auxiliary agent C is 0.1-8%.

[0023] In addition, the present invention also provides an application of a 2-chloro-3,3,3-trifluoropropene catalyst, which uses the above catalyst to prepare 2-chloro-3,3,3-trifluoropropene using 2,3,3,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane or a mixture of 1,1,2,3-tetrachloropropene and 1,1,1,2,3-pentachloropropane as a raw material.

[0024] The technical solution adopted by the present invention has the following beneficial effects:

[0025] 1. The additives A and C are introduced by the co-dropping method, and the crystallization environment is relatively stable; the number of crystal nuclei and the crystal growth rate are controlled by cooling, so that the metal hydroxide produces chromium hydroxide crystals with a lower degree of polymerization on the inner surface of the container, and flaky chromium hydroxide crystals are produced on the interface between the two phases. Due to the flaky skeleton structure, there is less carbon deposition when the material flows through the catalyst bed. Compared with other chromium-based catalysts, the reaction conditions are milder and the catalyst life is longer.

[0026] 2. The hydroxide crystals are crushed and immersed in the additive B solution, so as to further modify the corresponding transition metal additive on the flaky hydroxide skeleton and adjust the surface acidity of the catalyst, which is beneficial to further improve the catalyst's ability to resist carbon deposition. Compared with the comparative catalyst, 1233xf has higher selectivity (see Table 2) and is more conducive to the subsequent separation and purification process.

[0027] 3. The catalyst particles produced after granulation, calcination and fluorination have high density and strength, uniform morphology, retain a large number of pore structures, and have a large specific surface area, thereby exposing more active sites and improving the conversion rate.

[0028] The specific technical solutions and beneficial effects of the present invention will be described in detail in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0030] Figure 1 Experimental results for catalysts 1-8 Figure 1 ;

[0031] Figure 1a Experimental results for catalysts 1-8 Figure 2 ;

[0032] Figure 2 is the SEM image of the amorphous structure catalyst 7;

[0033] Figure 3 This is the SEM image of the sheet-like structure catalyst 8. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Those skilled in the art will appreciate that, in the absence of conflict, the features in the following embodiments and implementations may be combined with each other.

[0036] In order to improve the problem of severe carbon deposition and short catalyst life in the fluorine-chlorine exchange reaction, the present invention provides a method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination, wherein a precipitant is added in the presence of a soluble salt of chromium and additives A and C, and crystallizes with the solution at the liquid-solid interface on the inner surface of a low-temperature precipitation container to generate a crystalline precipitate, and then the crystalline precipitate of the solution in the container is filtered or centrifuged, washed with deionized water to a pH of about 7.5, and dried at 60-120°C for 2-60h to obtain a flaky hydroxide skeleton, i.e., a catalyst precursor. The flaky hydroxide skeleton is then crushed and immersed in an additive B solution, thereby introducing additive B.

[0037] The container contact material is selected from one of Q235B / Q245R / S304 / S316 / S316L / GG17 high borosilicate glass / G3.3 borosilicate glass / PFLUON polytetrafluoroethylene. The additive A is at least one of Fe, Co, Ni, Cu, and Zn salts, the additive B is at least one of Zr, Ce, Sn, Ti, Mn, W, and V salts, and the additive C is at least one of Mg, K, Na, Y, Hf, La, Sm, and B salts.

[0038] Preferably, the co-dropping method includes dropping the auxiliary agent A, the aqueous solution of the chromium salt, and the precipitant solution into the aqueous solution of the auxiliary agent C. It is understood that the co-dropping can be continuous or discontinuous. In addition, during the co-dropping method, the pH of the solution in the container is kept between 7 and 11.

[0039] Furthermore, the co-dropping method also includes continuously adding the aqueous solution of the auxiliary agent C. Of course, the aqueous solution of the auxiliary agent C may not be added.

[0040] In addition, during the co-drop feeding method, the temperature of the container is simultaneously reduced and the temperature difference between the center of the solution and the container wall is maintained between 10-30° C. The co-drop feeding can be performed by a feeding device, which extends into the container, close to the inner wall of the container and has a heat exchange device in the center of the feeding device, so that the solution temperature is maintained at 20-40° C. and the inner wall of the container is maintained at 0-25° C.

[0041] Specifically, the chromium salt is at least one of nitrate, acetate, and chloride. The auxiliary agent A and the auxiliary agent C are at least one of nitrate, acetate, chloride, oxychlorate, phosphate, isopropoxide, and citrate, and the ingredients of the auxiliary agent A and the auxiliary agent C are different. The auxiliary agent B is one of nitrate, acetate, and chloride. The solvent of the auxiliary agent B is at least one mixture of water, ethanol, methanol, acetone, ethylenediamine, ether, and ammonia water. The precipitant solution is an aqueous solution of at least one of sodium carbonate, sodium hydroxide, potassium hydroxide, ammonia, urea, and ammonium bicarbonate.

[0042] The molar composition ratio of the aqueous solution of the auxiliary agent A and the chromium salt is auxiliary agent A 1.0: chromium salt 4.9-20.0: water 50-500. The concentration of the aqueous solution of the auxiliary agent C is 0.001-0.5 mol / L. The mass ratio of the auxiliary agent B to the solvent in the auxiliary agent B solution is auxiliary agent B 1.0: solvent 20-400. The concentration of the precipitant solution is 0.1-8 mol / L.

[0043] Further, the molar composition ratio of the aqueous solution of the auxiliary agent A and the chromium salt is 1.0 auxiliary agent A: 4.9-12.0 chromium salt: 50-400 water. The mass ratio of the auxiliary agent B to the solvent in the auxiliary agent B solution is 1.0 auxiliary agent B: 50-300 solvent. The concentration of the aqueous solution of the auxiliary agent C is 0.01-0.5 mol / L. The concentration of the precipitant solution is 1-8 mol / L.

[0044] Referring to the preparation method of chromium-based catalyst in the prior art, after impregnation, it also includes the steps of removing solvent, granulation and calcination. Among them, stirring is first performed for 1-20 hours, and the temperature is increased to evaporate and recover the solvent; then the granulation method is to add 0.1-5wt% (relative to the mass ratio of the chromium-based catalyst precursor) of graphite and pressurize the granulation, and the particle size is 5-100 mesh; finally, the calcination method is to calcine at 400-800℃ under nitrogen for 3-72h, then cool to 250℃, slowly increase the temperature to 350℃, and gradually introduce HF during the heating process until pure HF gas is fluorinated.

[0045] Based on the above technical scheme, further, stirring for 1-16 hours, heating and stirring at 60-100°C to recover the solvent, adding 0.1-3wt% graphite and pressurizing to granulate, and calcining at 400-700°C under nitrogen for 3-72 hours.

[0046] In addition, a catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination is also provided, which is prepared by the above method.

[0047] The molar content of Cr in the catalyst is 40-85%, the molar content of the auxiliary agent A is 5-20%, the molar content of the auxiliary agent B is 0.2-12%, and the molar content of the auxiliary agent C is 0.1-8%.

[0048] Based on the above technical solution, further, the catalyst composition has Cr as the main element with a content of 40-75%, the auxiliary agent A is at least one of Fe, Co, Ni, Cu, Zn, and Mg salts with an element content of 5-18%, the auxiliary agent B is at least one of Zr, Ce, Sn, Ti, Mn, W, and V salts with an element content of 0.2-10%, and the auxiliary agent C is at least one of K, Na, Y, Hf, La, Sm, and B salts with an element content of 0.1-6%.

[0049] In addition, the catalyst regeneration method is as follows:

[0050] When the catalyst conversion rate is lower than 90%, the HF and feed valves are closed.

[0051] After calcining at 400-500℃ for 3-20h under nitrogen, regeneration begins. First, use 1% oxygen-nitrogen mixture to calcine at 400-500℃ for 20-120h, then use 5% oxygen-nitrogen mixture to calcine for 10-80h, and then use 10% oxygen-nitrogen mixture to calcine at 400-500℃. When the gas chromatogram detects no CO2 peak, stop calcining. Then cool to 250℃ and keep for 2-60h, slowly increase the temperature to 350℃, and gradually introduce HF until pure HF gas is fluorinated. Then cool to the reaction temperature and wait for the reaction to start.

[0052] In addition, the present invention provides an application of a 2-chloro-3,3,3-trifluoropropene catalyst, which uses the above catalyst to prepare 2-chloro-3,3,3-trifluoropropene using 2,3,3,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane or a mixture of 1,1,2,3-tetrachloropropene and 1,1,1,2,3-pentachloropropane as a raw material.

[0053] Preferably, under mild conditions of 170° C.-240° C., the ratio of HF to the raw material is: 1.0 raw material: 15-50 HF to prepare 2-chloro-3,3,3-trifluoropropene.

[0054] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0055] Example 1

[0056] 1. Preparation of Catalyst

[0057] (1) 856.7 g of zinc nitrate hexahydrate and 314.3 g of cobalt nitrate hexahydrate were added to 6 L of aqueous solution containing 6 mol / L Cr(NO3)3 and mixed evenly to prepare solution M. 12 L of aqueous solution N containing 0.03 mol / L samarium chloride. 6 mol / L potassium hydroxide aqueous solution P. Solution M and precipitant solution P were continuously added dropwise to 6 L of aqueous solution N containing samarium chloride. During the preparation process, 100 ml / min of auxiliary agent C solution was added. At the same time, the pH of the solution inside the reactor was maintained at 9.5. The liquid receiving material inside the reactor was GG17 high borosilicate glass. The liquid stirring speed was 500 rpm. While adding the materials, the wall temperature of the container was lowered to maintain the temperature at 10°C. The internal temperature of the solution was controlled at 25°C by the heating coil.

[0058] (2) Filter or centrifuge the precipitate, wash with deionized water until the pH value is 7.5, and dry at 120° C. for 48 h to obtain a gray-green block.

[0059] (3) After the catalyst precursor is crushed, it is impregnated with the additive B. The solvent is a mixture of water and ethanol, and the mass ratio of water to ethanol is 2:1. Take 63.1g of tin chloride pentahydrate and add it to 1.5L of solvent. Stir for 2h and then add the catalyst precursor.

[0060] (4) Stir for 6 hours, then gradually raise the temperature to 50°C and evaporate under reduced pressure to recover the solvent. When the catalyst is close to a non-Newtonian fluid, add 3wt% of graphite to the catalyst precursor and mix, pressurize and extrude to granulate, and then continue to dry. Load 100ml (about 60g) of the granulated catalyst precursor into a nickel tube fixed bed tubular reactor with an inner diameter of 36mm, roast at 520°C under nitrogen for 24 hours, then cool to 250°C and maintain for 6 hours, slowly raise the temperature to 350°C, and gradually introduce HF until pure HF gas is fluorinated. After fluorination for 40 hours, cool down. Nitrogen purges the HF on the catalyst surface. The catalyst is kept ready for use under nitrogen protection.

[0061] The catalyst is recorded as: Catalyst 1

[0062] 2. Preparation of 2-chloro-3,3,3-trifluoropropene by gas phase fluorination

[0063] 2 ml of fluorinated catalyst was loaded into a fixed bed tubular reactor with an inner diameter of 9 mm nickel tube, and then a mixture of HCC-240db and HCC-1230xa, with a mass ratio of HCC-240db and HCO-1230xa of 98:2, was preheated at 110°C and fully mixed with the preheated HF before entering the catalyst bed. The catalyst bed temperature was 240°C. The ratio of the amount of raw material to HF was maintained at 1:15. Raw material feed rate: 10 g / h. The tail gas was washed with water and KOH solution, dried, and analyzed by gas chromatography. The chromatographic column used was Agilent DB-624, the carrier gas was nitrogen, the injection port was 220°C, and the FID detector was 250°C.

[0064] Calculation method of reaction instantaneous conversion rate and selectivity:

[0065] The product composition was analyzed by gas chromatography, and the molar number of each product in the product was calculated by external standard method.

[0066]

[0067] For detailed experimental results, see Figure 1 and Figure 1a .

[0068] Example 2

[0069] Catalyst preparation:

[0070] (1) 731.9 g of magnesium chloride hexahydrate and 342.2 g of nickel chloride hexahydrate were added to 6 L of aqueous solution containing 6 mol / L Cr(NO3)3 and mixed evenly to prepare solution M. 12 L of aqueous solution N containing 0.003 mol / L lanthanum chloride. 6 mol / L ammonia solution P. Solution M and precipitant solution P were continuously added dropwise to 12 L of aqueous solution N containing lanthanum chloride. During the preparation process, solution N was not added. At the same time, the pH of the solution inside the reactor was maintained at 8.5. The material of the liquid receiving material inside the reactor was Q235B, and the liquid stirring speed was 300 rpm. While adding the materials, the wall temperature of the container was lowered to maintain a temperature of 15°C, and the internal temperature of the solution was controlled at 20°C by the heating coil.

[0071] (2) Filter or centrifuge the precipitate, wash with deionized water until the pH value is 7.5, and dry at 110°C for 48 hours to obtain a gray mass.

[0072] (3) After the catalyst precursor is crushed, it is impregnated with the additive B. The solvent is water. 142.4 g of manganese chloride tetrahydrate and 44.4 g of ammonium metatungstate are added to 1.5 L of solvent and stirred for 2 h before adding the catalyst precursor.

[0073] (4) Stir for 6 hours, then gradually raise the temperature to 50°C and evaporate under reduced pressure to recover the solvent. When the catalyst is close to a non-Newtonian fluid, add 5wt% of graphite in the catalyst precursor and mix and discharge it, pressurize and extrude it into granules, and then continue to dry it. Load 100ml (about 55g) of the granulated catalyst precursor into a nickel tube fixed bed tubular reactor, roast it at 500°C under nitrogen for 30 hours, then cool it to 250°C and keep it for 10 hours, slowly heat it to 350°C, and gradually introduce HF until pure HF gas is fluorinated. After fluorination for 40 hours, cool it down. Nitrogen purges the HF on the catalyst surface. The catalyst is ready for use under nitrogen protection. The reaction conditions are the same as those in Example 1.

[0074] The catalyst is recorded as: Catalyst 2

[0075] For detailed experimental results, see Figure 1 and Figure 1a .

[0076] Example 3

[0077] Preparation of catalyst:

[0078] (1) 1047.7g of cobalt nitrate hexahydrate, 256.7g of nickel chloride hexahydrate and 146.4g of magnesium chloride hexahydrate were added to 6L of aqueous solution containing 6mol / L Cr(NO3)3 and mixed evenly to prepare solution M. 12L of aqueous solution N containing 0.015mol / L yttrium chloride. 3mol / L ammonia solution P. Solution M and precipitant solution P were continuously added dropwise to 6L of aqueous solution N containing yttrium chloride. During the preparation process, aqueous solution N was added at a rate of 100ml / min. At the same time, the pH value of the solution inside the reactor was maintained at 10. The liquid receiving material inside the reactor was PFLUON polytetrafluoroethylene, and the liquid stirring speed was 300rpm. While adding the materials, the wall temperature of the container was lowered to maintain a temperature of 15°C, and the internal temperature of the solution was controlled at 30°C by a heating coil.

[0079] (2) Filter or centrifuge the precipitate, wash with deionized water until the pH value is 7.5, and dry at 110° C. for 48 h to obtain a blue-gray block.

[0080] (3) After the catalyst precursor is crushed, it is impregnated with the auxiliary agent B. The solvent is ethanol. Take 71.2g of manganese chloride tetrahydrate and add it to 1.5L of the solvent. Stir for 6h and then add the catalyst precursor.

[0081] (4) Stir for 12 hours, then gradually raise the temperature to 80°C to evaporate and recover the solvent. When the catalyst is close to a non-Newtonian fluid, add 5wt% of graphite in the catalyst precursor and mix and discharge, pressurize and extrude into granules, and then continue to dry. Load 100ml (about 65g) of the granulated catalyst precursor into a nickel tube fixed bed tubular reactor, calcine at 500°C under nitrogen for 20 hours, then cool to 250°C and maintain for 10 hours, slowly heat to 350°C, and gradually introduce HF until pure HF gas is fluorinated. Then cool to the reaction temperature and wait for the reaction to start. The reaction conditions are the same as in Example 1.

[0082] The catalyst is recorded as: Catalyst 3

[0083] For detailed experimental results, see Figure 1 and Figure 1a .

[0084] Example 4

[0085] Example 4 was carried out in the same manner as Example 1, except that in the catalyst preparation method, 131.3 g of samarium chloride hexahydrate was added to solution M, and solution N was replaced with deionized water. The precipitant was changed to 3 mol / L sodium hydroxide solution, the liquid receiving material inside the reactor was 316L, and the reaction conditions were the same as in Example 1.

[0086] Catalyst label: Catalyst 4

[0087] For detailed experimental results, see Figure 1 and Figure 1a .

[0088] Example 5

[0089] Example 5 was carried out in the same manner as Example 2, except that in the catalyst preparation method, 12.72 g of lanthanum chloride hexahydrate was added to solution M, and solution N was replaced with deionized water. The precipitant was changed to 1 mol / L ammonium bicarbonate solution, and the material for the liquid inside the reactor was S304. The reaction conditions and regeneration conditions were the same as those in Example 1. The catalyst was labeled as: Catalyst 5

[0090] For detailed experimental results, see Figure 1 and Figure 1a .

[0091] Example 6

[0092] Example 6 was carried out in the same manner as Example 3, except that in the catalyst preparation method, 54.6 g of yttrium chloride hexahydrate was added to solution M, and solution N was replaced with deionized water. The reaction conditions and regeneration conditions were the same as those of Example 3. The catalyst was labeled as: Catalyst 6

[0093] For detailed experimental results, see Figure 1 and Figure 1a .

[0094] Example 7

[0095] Preparation of catalyst:

[0096] 1047.7g of cobalt nitrate hexahydrate, 256.7g of nickel chloride hexahydrate and 146.4g of magnesium chloride hexahydrate were added to 6L aqueous solution containing 6mol / L Cr(NO3)3 and mixed evenly to form solution M. 3mol / L ammonia solution P. The precipitant solution P was continuously added dropwise to solution M. The liquid receiving material inside the reactor was PFLUON polytetrafluoroethylene, and the liquid stirring speed was 300rpm. The solution temperature was maintained at 15°C while adding the materials. Until the pH of the precipitation solution was 8.5. Other preparation conditions and reaction conditions were the same as those in Example 3.

[0097] The catalyst is recorded as: Catalyst 7

[0098] For detailed experimental results, see Figure 1 and Figure 1a The catalyst was shown in SEM. Figure 2 .

[0099] Example 8

[0100] Preparation of catalyst:

[0101] (1) 1047.7 g of cobalt nitrate hexahydrate, 342.3 g of nickel chloride hexahydrate and 92.3 g of magnesium chloride hexahydrate were added to 6 L of aqueous solution containing 6 mol / L Cr(NO3)3 and mixed evenly to prepare solution M. 12 L of aqueous solution N containing 0.03 mol / L yttrium chloride. 3 mol / L ammonia solution P. Solution M and precipitant solution P were continuously added dropwise to 6 L of aqueous solution N containing yttrium chloride. During the preparation process, aqueous solution N was added at 50 ml / min. At the same time, the pH value of the solution inside the reactor was maintained at 9. The liquid receiving material inside the reactor was GG17 high borosilicate glass. The liquid stirring speed was 300 rpm. While adding the materials, the wall temperature of the container was lowered to maintain the temperature at 10°C. The internal temperature of the solution was controlled at 25°C by the heating coil.

[0102] (2) Filter or centrifuge the precipitate, wash with deionized water until the pH value is 7.5, and dry at 110° C. for 48 h to obtain a blue-gray block.

[0103] (3) After the catalyst precursor is crushed, it is impregnated with the additive B. The solvent is acetone. Take 35.6g of manganese chloride tetrahydrate and 71.3g of tungsten chloride and add them to 1L of solvent. Stir for 6h and then add the catalyst precursor.

[0104] (4) Stir for 12 hours, and then evaporate and recover the solvent by distillation at 30°C under reduced pressure. When the catalyst is close to a non-Newtonian fluid, add 5wt% of graphite in the catalyst precursor and mix and discharge it. Pressurize and extrude it into granules and continue drying. Load 100ml (about 65g) of the granulated catalyst precursor into a nickel tube fixed bed tubular reactor, calcine it at 450°C under nitrogen for 20 hours, then cool it to 250°C and keep it for 10 hours, slowly heat it to 350°C, and gradually introduce HF until pure HF gas is fluorinated. After fluorination for 40 hours, cool it down. Nitrogen purges the HF on the catalyst surface. The catalyst is kept ready for use under nitrogen protection. The reaction conditions are the same as those in Example 1.

[0105] The catalyst is recorded as: Catalyst 8

[0106] For detailed experimental results, see Figure 1 and Figure 1a The catalyst was observed by scanning electron microscopy. Figure 3 .

[0107] Example 9

[0108] Example 9 uses the same catalyst as Example 1, but differs from Example 1 in the reaction conditions.

[0109] The reaction conditions are as follows:

[0110] 80ml of fluorinated catalyst was loaded into a fixed bed tubular reactor with an inner diameter of 36mm nickel tube, and then the raw material HCC-240db (water content less than 20ppm as determined by Karl Fischer moisture meter) was preheated at 110℃, fully mixed with the preheated HF and then entered the catalyst bed. The catalyst bed temperature was 180℃. The ratio of raw material to HF substance was maintained at 1:30. Raw material feed rate: 24g / h. The tail gas was washed with water and KOH solution, dried, and analyzed by gas chromatography. The chromatographic column used was Agilent DB-624, carrier gas: nitrogen, injection port 220℃, FID detector 250℃.

[0111] The reaction results are shown in Table 1.

[0112] Example 10

[0113] Example 10 used the same catalyst as Example 6, and the reaction conditions were the same as Example 9. The reaction results are shown in Table 1.

[0114] Embodiment 11

[0115] Example 11 used the same catalyst as Example 8, and the reaction conditions were the same as Example 9. The reaction results are shown in Table 1.

[0116] Table 1

[0117]

[0118] Comparative Example

[0119] The following comparative examples are provided in conjunction with comparative patents 1-4 in the background art.

[0120] Comparative Example 1

[0121] The catalyst preparation method is as described in comparative patent 1: 82.5g of sodium silicate is dissolved in 2850ml of 28% ammonia water and 6kg of chromium trichloride aqueous solution (chromium content of about 10%) is added under vigorous stirring. The pH after mixing is about 7. The precipitate is collected by filtration, washed with deionized water, dried, and calcined at 450°C under nitrogen flow to obtain a silicon-containing precursor chromium salt. The precursor is treated with hydrogen fluoride diluted with nitrogen (hydrogen fluoride: nitrogen = 1:3) at room temperature for 4 hours to obtain porous chromium fluoride (PCrF). 250g of SbCl5 is slowly added to the tablet-shaped porous chromium fluoride (PCrF) in an N2 atmosphere. In this way, a PCrF tablet containing SbCl5 is obtained. After the tablet is dried at 100°C under circulating N2, it is treated at 100°C with anhydrous HF (AHF) diluted with N2 (N2 / AHF = 1 / 1), and then the temperature and the concentration of AHF are increased, and finally treated with pure AHF at 200°C. The last remaining HF was removed by blowing N2 gas, and the catalyst was recorded as Comparative Catalyst 1.

[0122] Comparative Example 2

[0123] The catalyst preparation method is as described in comparative patent 3: 83.5 g of Fe(NO3)3·9H2O and 317.9 g of Mg(NO3)2·6H2O are prepared into a mixed solution at a molar ratio of Fe element to Mg element of 1:6, heated to 40°C, 124 g of urea and a certain amount of ammonia water are added thereto, the pH value is adjusted to 9.5, aged for 1 hour, the temperature is increased to 90°C, and the aging is continued for 8 hours, filtered, the obtained colloidal precipitate product is washed to neutrality, dried at 120°C, and the obtained solid is roasted at 500°C for 6 hours to obtain Fe-Mg composite oxide.

[0124] Take 100g of Fe-Mg composite oxide and 25g of magnesium carbonate, mix them in a mass ratio of 4:1, grind them thoroughly with a ball mill, and then make tablets to obtain a catalyst precursor. The catalyst precursor is calcined at 400°C in a muffle furnace for 8 hours, then 100ml of the catalyst precursor is loaded into a tubular reactor, cooled to 200°C, and hydrogen fluoride gas is introduced. The exothermic temperature rise of the reaction is controlled to be less than 20°C, and the HF flow rate is gradually increased to 500ml / min. When the temperature drops to 200°C, fluorination is continued for 1 hour, and then the temperature is increased to 400°C at a heating rate of 1°C / min, and fluorination is continued for 8 hours to obtain a fluorination catalyst. This catalyst is recorded as comparative catalyst 2.

[0125] Comparative Example 3

[0126] The catalyst preparation method is as described in the comparative patent 4: the mass percentage composition of the fluorination catalyst precursor is as follows:

[0127] FeCl3 30.0%

[0128] MnCl2 0.5%

[0129] CaCO3 69.5%

[0130] Ferric chloride and MnCl2 were dissolved in water to prepare an impregnation solution, CaCO3 was added, and the solution was impregnated for 1 hour. The water in the impregnation solution was evaporated by rotary evaporation, and the solution was dried in an oven at 120°C for 8 hours to obtain a catalyst precursor. The obtained catalyst precursor was calcined at 450°C in a muffle furnace for 8 hours, and then loaded into a tubular reactor, heated to 300°C, fluorinated with hydrogen fluoride gas for 1 hour, and then heated to 400°C at a heating rate of 1°C / min, and fluorinated for 8 hours to obtain a calcium fluoride-based fluorination catalyst. This catalyst is recorded as comparative catalyst 3.

[0131] Catalyst Evaluation:

[0132] Catalyst 8 was evaluated according to the reaction conditions of Example 9. The results are shown in Table 2.

[0133] Comparative catalysts 1, 2, and 3 were evaluated under the following reaction conditions (refer to comparative patent 3): 80 ml of fluorination catalyst was loaded into a nickel tube fixed bed tubular reactor with an inner diameter of 36 mm, HF and 1,1,2,3-tetrachloropropene were introduced for reaction, the flow rate of 1,1,2,3-tetrachloropropene was 24 g / h, the molar ratio of HF to 1,1,2,3-tetrachloropropene was controlled to be 15:1, the contact time was 10 seconds, and the reaction temperature was 260°C. The results are shown in Table 2.

[0134] Table 2

[0135]

[0136] Gas Phase Fluorination Catalyst Regeneration

[0137] Close the HF and raw material valves, and start regeneration after calcining at 450℃ under nitrogen for 12h. First, use a 1% oxygen-nitrogen mixture to calcine at 450℃ for 120h, then use a 5% oxygen-nitrogen mixture to calcine for 48h, and then use a 10% oxygen-nitrogen mixture to calcine. When the gas chromatographic detection shows no CO2 peak, stop calcining. Then cool to 250℃ and keep for 6h, slowly heat to 350℃, and gradually introduce HF until pure HF gas is fluorinated. Then cool to the reaction temperature and wait for the reaction to start. The chromatographic column uses HP-PLOT Q carrier gas: helium, 30m*0.53mm*40μm, injection port 200℃, TCD detector 250℃. After regeneration, the reaction results are shown in Table 3.

[0138] Table 3

[0139]

[0140] Table 4 Textural properties after fluorination with different catalysts

[0141] catalyst <![CDATA[S BET (m 2 / g)]]> <![CDATA[V BJH (cm 3 / g)]]> <![CDATA[D bore (nm)]]> Example 1 163.463 0.316 3.660 Example 3 176.494 0.301 3.645 Example 7 195.923 0.448 3.651 Example 8 177.603 0.311 3.658

[0142] Table 4 S BET is the specific surface area, V BJH Pore ​​volume, D bore is the aperture.

[0143] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination, It is characterized in that The steps include: In a reaction container, the chromium salt solution is introduced into the auxiliary agent A and the auxiliary agent C in the presence of a precipitant by a co-dropping method, and the solution inside the container is kept alkaline, and hydroxide crystals are generated in the container at a reduced temperature; The hydroxide crystals are crushed and immersed in a solution of the additive B, thereby introducing the additive B; Among them, the auxiliary agent A is at least one of Fe, Co, Ni, Cu, and Zn salts, the auxiliary agent B is at least one of Zr, Ce, Sn, Ti, Mn, W, and V salts, and the auxiliary agent C is at least one of Mg, K, Na, Y, Hf, La, Sm, and B salts.

2. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 1, It is characterized in that The co-dropping method includes dropping the auxiliary agent A, the aqueous solution of the chromium salt and the precipitant solution into the aqueous solution of the auxiliary agent C.

3. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 2, It is characterized in that The co-dropping method further includes continuously adding the aqueous solution of the auxiliary agent C; and / or, during the co-dropping method, maintaining the pH of the solution inside the container between 7-11.

4. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 2, It is characterized in that During the co-dropping process, the container temperature is lowered and the temperature difference between the solution center and the container wall is maintained between 10-30°C; wherein the solution temperature is maintained at 20-40°C and the container inner wall is maintained at 0-25°C.

5. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 2, It is characterized in that The chromium salt is at least one of nitrate, acetate, and chloride; and / or, the auxiliary agent A and the auxiliary agent C are at least one of nitrate, acetate, chloride, oxychlorate, phosphate, isopropoxide, and citrate, and the components of the auxiliary agent A and the auxiliary agent C are different; and / or, the auxiliary agent B is at least one of nitrate, acetate, and chloride; and / or, the solvent of the auxiliary agent B is at least one of water, ethanol, methanol, acetone, ethylenediamine, ether, and ammonia water; and / or, the precipitant solution is an aqueous solution of at least one of sodium carbonate, sodium hydroxide, potassium hydroxide, ammonia, urea, and ammonium bicarbonate.

6. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 5, It is characterized in that The molar ratio of the auxiliary agent A to the aqueous solution of the chromium salt is auxiliary agent A 1.0: chromium salt 4.9-20.0: water 50-500; and / or, the concentration of the aqueous solution of the auxiliary agent C is 0.001-0.5 mol / L; and / or, the mass ratio of the auxiliary agent B to the solvent in the auxiliary agent B solution is auxiliary agent B 1.0: solvent 20-400; and / or, the concentration of the precipitant solution is 0.1-8 mol / L.

7. A method for preparing a catalyst for 2-chloro-3,3,3-trifluoropropene by gas phase fluorination according to claim 1, It is characterized in that The method further comprises the steps of removing the solvent after impregnation, granulating and calcining; wherein the granulating method is to add 0.1-5wt% graphite and pressurize the granules; the calcining method is to calcine at 400-800°C under nitrogen for 3-72h, then cool down to 250°C, heat up to 350°C, and gradually introduce HF during the heating process until pure HF gas is fluorinated.

8. A catalyst for preparing 2-chloro-3,3,3-trifluoropropene by gas phase fluorination, It is characterized in that The method according to any one of claims 1 to 7 is used to prepare the present invention.

9. The catalyst according to claim 8, It is characterized in that The molar content of Cr in the catalyst is 40-85%; and / or the molar content of the auxiliary agent A is 5-20%; and / or the molar content of the auxiliary agent B is 0.2-12%; and / or the molar content of the auxiliary agent C is 0.1-8%.

10. Application of a 2-chloro-3,3,3-trifluoropropene catalyst, It is characterized in that The catalyst according to claim 8 or 9 is used for preparing 2-chloro-3,3,3-trifluoropropene using 2,3,3,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane or a mixture of 1,1,2,3-tetrachloropropene and 1,1,1,2,3-pentachloropropane as a raw material.

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