Supported chromium-based catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a supported chromium-based catalyst as well as a preparation method and application thereof. The supported chromium-based catalyst comprises a carrier and chromium oxyfluoride; the carrier comprises spinel type nickel ferrite, the chemical formula of the spinel type nickel ferrite is M1-xNixFe2O4, x is more than or equal to 0.5 and less than or equal to 1, and M comprises at least one of Zn, Co, Cu, Mn, Mg, Ba and Sr. When the supported chromium-based catalyst is used as a catalyst for a fluorination reaction, the fluorination reaction has high conversion rate and selectivity, and in addition, the catalyst also has the advantage of long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a supported chromium-based catalyst and a preparation method and application thereof. Background Art

[0002] Chromium-based catalysts are a common fluorination catalyst, typically used in gas-phase catalytic fluorination reactions, where halogenated hydrocarbons react with hydrogen fluoride to produce fluorinated products. However, chromium-based catalysts currently suffer from short service life, prone to carbon deposition, easy loss of hexavalent chromium ions, and low fluorination conversion and selectivity. Currently, the industry primarily addresses carbon deposition by continuously aerating oxygen (O2) during the reaction, but this increases costs and makes the O2 flow rate difficult to control.

[0003] Patent publication number CN102631938A discloses a method for preparing a chromium-based catalyst by introducing a carbon template agent into a sucrose-citric acid solution, but the conversion rate and selectivity are very low, and there is no stability data; Patent publication number CN107848915A discloses a method comprising two different Cr2p 3 / 2 The invention discloses a chromium oxyfluoride catalyst with high binding energy, but the catalytic performance of the catalyst is general. The conversion rate of some halogenated hydrocarbons in the embodiments is only 29.9%, and the stable operation time of the catalyst is only 95 hours.

[0004] Therefore, there is still an urgent need for a catalyst for fluorination reaction with high catalytic activity, high selectivity, low carbon deposition and long service life. Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, the present invention provides a supported chromium-based catalyst, a preparation method, and applications thereof. Using this supported chromium-based catalyst as a catalyst for a fluorination reaction can achieve high conversion and selectivity, and the catalyst also has the advantage of a long service life.

[0006] To this end, the first aspect of the present invention provides a supported chromium-based catalyst, the supported chromium-based catalyst comprising a carrier and chromium oxyfluoride;

[0007] The carrier includes spinel nickel ferrite, whose chemical formula is M 1-x Ni x Fe2O4, wherein 0.5≤x≤1, and M includes at least one of Zn, Co, Cu, Mn, Mg, Ba, and Sr.

[0008] The supported chromium-based catalyst provided by the present invention solves the problem of chromium having catalytic activity in traditional chromium-based catalysts. 6+ The problem of easy loss and easy carbon deposition of chromium-based catalysts is solved, thereby extending the service life of the catalyst.

[0009] According to an embodiment of the present invention, the mass ratio of the chromium element in the chromium oxyfluoride to the carrier is (5-30):100.

[0010] According to an embodiment of the present invention, the specific surface area of ​​the carrier is 250m 2 / g-400m 2 / g.

[0011] The second aspect of the present invention provides a method for preparing the supported chromium-based catalyst according to the first aspect, the preparation method comprising the following steps:

[0012] Step S1: mixing an Fe source, a Ni source, an optional M source and water, then adding alkali dropwise to obtain a mixed solution A, stirring, cooling, obtaining a precipitate, washing, drying, and performing a first calcination treatment to obtain a carrier powder;

[0013] Step S2: adding the Cr source solution dropwise to the carrier powder obtained in step S1 for impregnation to obtain a first intermediate;

[0014] Step S3: performing a second calcination treatment on the first intermediate under a N2 / O2 mixed atmosphere to obtain a second intermediate;

[0015] Step S4: activating the second intermediate under a HF / N2 mixed atmosphere to obtain the supported chromium-based catalyst.

[0016] The supported chromium-based catalyst can be prepared by the preparation method provided by the present invention, and the catalyst has the advantage of long service life.

[0017] According to an embodiment of the present invention, the M source includes at least one of a Zn source, a Co source, a Cu source, a Mn source, a Mg source, a Ba source, and a Sr source.

[0018] According to an embodiment of the present invention, the M source includes nitrate or nitrate hydrate, chloride or chloride hydrate, sulfate or sulfate hydrate, oxalate or oxalate hydrate of at least one metal among Zn, Co, Cu, Mn, Mg, Ba, and Sr.

[0019] According to an embodiment of the present invention, the Fe source includes at least one of Fe(NO3)3, Fe(NO3)3·9H2O, FeCl3, FeCl3·6H2O, and Fe2(SO4)3.

[0020] According to an embodiment of the present invention, the Ni source includes at least one of Ni(NO3)2, Ni(NO3)2·6H2O, NiCl2, NiCl2·6H2O, and NiSO4.

[0021] According to an embodiment of the present invention, the Zn source includes at least one of Zn(NO3)2, Zn(NO3)2·6H2O, ZnCl2, ZnCl2·6H2O, and ZnSO4.

[0022] According to an embodiment of the present invention, the Co source includes at least one of Co(NO3)2, Co(NO3)2·6H2O, CoCl2, CoCl2·6H2O, CoSO4·7H2O, and CoC2O4·2H2O.

[0023] According to an embodiment of the present invention, the Cu source includes at least one of Cu(NO3)2, Cu(NO3)2·3H2O, CuCl2, CuCl2·6H2O, CuSO4·5H2O, and CuC2O4.

[0024] According to an embodiment of the present invention, the Mn source includes at least one of Mn(NO3)2, Mn(NO3)2·4H2O, MnCl2, MnCl2·4H2O, and MnSO4.

[0025] According to an embodiment of the present invention, the Mg source includes at least one of Mg(NO3)2, Mg(NO3)2·6H2O, MgCl2, MgCl2·6H2O, and MgSO4.

[0026] According to an embodiment of the present invention, the base is added in an amount such that the pH of the mixed solution A is 8.5-11.

[0027] According to an embodiment of the present invention, the base is added in an amount such that the pH of the mixed solution A reaches 10.

[0028] According to an embodiment of the present invention, the Ba source includes at least one of Ba(NO3)2 and BaCl2.

[0029] According to an embodiment of the present invention, the Sr source includes at least one of Sr(NO3)2 and SrCl2·6H2O.

[0030] According to an embodiment of the present invention, the base includes at least one of NaOH, KOH, and ammonia water.

[0031] According to an embodiment of the present invention, the mixing temperature in step S1 is 40°C-80°C.

[0032] According to an embodiment of the present invention, the mixing time in step S1 is 2 hours to 6 hours.

[0033] According to an embodiment of the present invention, the stirring temperature in step S1 is 40°C-80°C.

[0034] According to an embodiment of the present invention, the stirring time in step S1 is 2 hours to 6 hours.

[0035] According to an embodiment of the present invention, the washing in step S1 is performed by alternating washing with water and ethanol.

[0036] According to an embodiment of the present invention, the washing in step S1 is performed by alternating washing with water and ethanol for 1-5 times.

[0037] According to an embodiment of the present invention, the temperature of the first calcination treatment is 600°C-1000°C.

[0038] According to an embodiment of the present invention, the time of the first calcination treatment is 3 hours to 10 hours.

[0039] According to an embodiment of the present invention, the Cr source includes at least one of Cr(NO3)3 or its hydrate, and CrCl3 or its hydrate.

[0040] According to an embodiment of the present invention, the Cr source includes at least one of Cr(NO 3 ) 3 ·9H 2 O and CrCl 3 ·6H 2 O.

[0041] According to an embodiment of the present invention, the ratio of the mass of the Cr element in the Cr source solution to the mass of the carrier powder is (5-30):100.

[0042] According to an embodiment of the present invention, the immersion temperature in step S2 is 25°C-80°C.

[0043] According to an embodiment of the present invention, the immersion time in step S2 is 2 hours to 6 hours.

[0044] According to an embodiment of the present invention, the solvent in the Cr source solution includes water.

[0045] According to an embodiment of the present invention, the immersion in step S2 is performed under ultrasonic conditions.

[0046] According to an embodiment of the present invention, the step S2 further includes filtering and drying after the impregnation is completed.

[0047] According to an embodiment of the present invention, after the impregnation is completed, the step S2 further includes filtering and drying, the drying temperature is 80° C.-110° C., and the drying time is 10 h-24 h.

[0048] According to an embodiment of the present invention, the volume fraction of O2 in the N2 / O2 mixed atmosphere is 1%-10%.

[0049] According to an embodiment of the present invention, the temperature of the second calcination treatment is 300°C-500°C.

[0050] According to an embodiment of the present invention, the second calcination treatment is performed for 4 hours to 10 hours.

[0051] According to an embodiment of the present invention, the volume fraction of HF in the HF / N2 mixed atmosphere is 35%-70%.

[0052] According to an embodiment of the present invention, the temperature of the activation treatment is 200°C-400°C.

[0053] According to an embodiment of the present invention, the activation treatment time is 8h-24h.

[0054] The third aspect of the present invention provides the use of the supported chromium-based catalyst described in the first aspect or the supported chromium-based catalyst prepared according to the preparation method described in the second aspect in the fluorination reaction of C3 halocarbons.

[0055] A fourth aspect of the present invention provides a method for fluorinating a C3 halogenated hydrocarbon, comprising:

[0056] contacting a first halogenated hydrocarbon, HF, and a supported chromium-based catalyst to perform a fluorination reaction to obtain a second halogenated hydrocarbon;

[0057] Wherein, the supported chromium-based catalyst is the supported chromium-based catalyst described in the first aspect or the supported chromium-based catalyst prepared according to the preparation method described in the second aspect.

[0058] The supported chromium-based catalyst provided by the present invention can be used as a catalyst for fluorination reaction and improves the conversion rate and selectivity of the fluorination reaction.

[0059] According to an embodiment of the present invention, the molar ratio of the first halogenated hydrocarbon to HF is 1:(5-20).

[0060] According to an embodiment of the present invention, the first halogenated hydrocarbon includes one of 1,1,1,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane, 1,1,1,3,3-pentachloropropane, 1,1,2,3-tetrachloropropene, 1-chloro-3,3,3-trifluoropropene, and 2-chloro-3,3,3-trifluoropropene.

[0061] According to an embodiment of the present invention, the temperature of the fluorination reaction is 200°C-400°C.

[0062] According to an embodiment of the present invention, the contact time of the fluorination reaction is 1s-100s.

[0063] According to an embodiment of the present invention, the second halogenated hydrocarbon includes one of 3,3,3-trifluoropropene, 2-chloro-3,3,3-trifluoropropene, 1-chloro-3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, and 2,3,3,3-tetrafluoropropene.

[0064] According to an embodiment of the present invention, the first halogenated hydrocarbon is 1,1,1,3-tetrachloropropane, and the second halogenated hydrocarbon is 3,3,3-trifluoropropene.

[0065] According to an embodiment of the present invention, the first halogenated hydrocarbon is 1,1,1,2,3-pentachloropropane, and the second halogenated hydrocarbon is 2-chloro-3,3,3-trifluoropropene.

[0066] According to an embodiment of the present invention, the first halogenated hydrocarbon is 1,1,1,3,3-pentachloropropane, and the second halogenated hydrocarbon is 1-chloro-3,3,3-trifluoropropene.

[0067] According to an embodiment of the present invention, the first halogenated hydrocarbon is 1,1,2,3-tetrachloropropene, and the second halogenated hydrocarbon is 2-chloro-3,3,3-trifluoropropene.

[0068] According to an embodiment of the present invention, the first halogenated hydrocarbon is 1-chloro-3,3,3-trifluoropropene, and the second halogenated hydrocarbon is 1,3,3,3-tetrafluoropropene.

[0069] According to an embodiment of the present invention, the first halogenated hydrocarbon is 2-chloro-3,3,3-trifluoropropene, and the second halogenated hydrocarbon is 2,3,3,3-tetrafluoropropene.

[0070] Beneficial effects

[0071] Compared with the prior art, an embodiment of the present invention has at least one of the following beneficial technical effects:

[0072] (1) The catalyst provided by the present invention has high catalytic activity, high substrate conversion rate and high selectivity of fluorination reaction products in the catalytic reaction. 6+ Not easy to lose or deposit carbon, long service life.

[0073] (2) The catalyst prepared by using the carrier provided by the present invention has good stability, Cr 6+ It is not easy to lose, has a long service life, and has unexpected technical effects.

[0074] (3) The catalyst prepared by using the carrier provided by the present invention is not prone to carbon deposition, has a long service life, and has unexpected technical effects.

[0075] (4) The present invention preferably incorporates an element M (such as Zn, Sr, or Ba) into the preparation of the catalyst, which is more conducive to improving the catalytic activity of the resulting catalyst and is more conducive to improving the substrate conversion rate and target product selectivity of the catalytic reaction.

[0076] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0077] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0078] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0079] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0080] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which the present invention belongs.

[0081] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention, but not excluding other contents.

[0082] As used herein, the terms "optionally," "optional," or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0083] The term "vol%" means volume percentage.

[0084] According to an embodiment of the present invention, a first aspect of the present invention provides a supported chromium-based catalyst, the supported chromium-based catalyst comprising a carrier and chromium oxyfluoride;

[0085] The carrier includes spinel nickel ferrite, whose chemical formula is M 1-x Ni x Fe2O4, wherein 0.5≤x≤1, and M includes at least one of Zn, Co, Cu, Mn, Mg, Ba, and Sr.

[0086] The supported chromium-based catalyst provided by the application utilizes the adsorption of spinel nickel ferrite to heavy metal ions (hexavalent chromium ions Cr 6+ ) and the characteristics of rich lattice oxygen, solves the problems of easy loss of Cr 6+ with catalytic activity in the chromium-based catalyst and easy carbon deposition of the chromium-based catalyst, and prolongs the service life thereof; the doping of M can cause lattice defects of the ferrite, thereby regulating the active sites of the carrier and the Lewis acidity of the catalyst, and further improving the conversion rate and selectivity of the chromium-based catalyst to fluorination reaction.

[0087] According to a specific embodiment of the application, the mass ratio of chromium element to carrier in the chromium oxyfluoride is (5-30):100, and as some specific examples, the mass ratio of chromium element to carrier in the chromium oxyfluoride can be 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, etc.

[0088] According to a specific embodiment of the application, the specific surface area of the carrier is 250m 2 / g-400m 2 / g, and as some specific examples, the specific surface area of the carrier can be 250m 2 / g, 300m 2 / g, 350m 2 / g, 400m 2 / g, etc. Specifically, the measurement method of the specific surface area is not particularly limited, and for example, the BET method can be used for measurement.

[0089] According to an embodiment of the application, the second aspect of the application provides a preparation method of the supported chromium-based catalyst of the first aspect, and the preparation method comprises the following steps:

[0090] Step S1: mixing a Fe source, a Ni source, an optional M source and water, then adding dropwise an alkali to obtain a mixed solution A, stirring, cooling to obtain a precipitate, washing, drying, first calcination treatment, and obtaining a carrier powder.

[0091] According to a specific embodiment of the application, the type of the M source is not particularly limited, and as some specific examples, the M source comprises at least one of a Zn source, a Co source, a Cu source, a Mn source, a Mg source, a Ba source and a Sr source.

[0092] According to a specific embodiment of the application, the M source comprises at least one of a nitrate or a hydrate of a nitrate, a chloride or a hydrate of a chloride, a sulfate or a hydrate of a sulfate, an oxalate or a hydrate of an oxalate of Zn, Co, Cu, Mn, Mg, Ba and Sr.

[0093] According to a specific embodiment of the present invention, the type of the Fe source is not particularly limited. As some specific examples, the Fe source includes at least one of Fe(NO3)3, Fe(NO3)3·9H2O, FeCl3, FeCl3·6H2O, and Fe2(SO4)3.

[0094] According to a specific embodiment of the present invention, the type of the Ni source is not particularly limited. As some specific examples, the Ni source includes at least one of Ni(NO3)2, Ni(NO3)2·6H2O, NiCl2, NiCl2·6H2O, and NiSO4.

[0095] According to a specific embodiment of the present invention, the type of the Zn source is not particularly limited. As some specific examples, the Zn source includes at least one of Zn(NO3)2, Zn(NO3)2·6H2O, ZnCl2, ZnCl2·6H2O, and ZnSO4.

[0096] According to a specific embodiment of the present invention, the type of the Co source is not particularly limited. As some specific examples, the Co source includes at least one of Co(NO3)2, Co(NO3)2·6H2O, CoCl2, CoCl2·6H2O, CoSO4·7H2O, and CoC2O4·2H2O.

[0097] According to a specific embodiment of the present invention, the type of the Cu source is not particularly limited. As some specific examples, the Cu source includes at least one of Cu(NO3)2, Cu(NO3)2·3H2O, CuCl2, CuCl2·6H2O, CuSO4·5H2O, and CuC2O4.

[0098] According to a specific embodiment of the present invention, the type of the Mn source is not particularly limited. As some specific examples, the Mn source includes at least one of Mn(NO3)2, Mn(NO3)2·4H2O, MnCl2, MnCl2·4H2O, and MnSO4.

[0099] According to a specific embodiment of the present invention, the type of the Mg source is not particularly limited. As some specific examples, the Mg source includes at least one of Mg(NO3)2, Mg(NO3)2·6H2O, MgCl2, MgCl2·6H2O, and MgSO4.

[0100] According to a specific embodiment of the present invention, the type of the Ba source is not particularly limited. As some specific examples, the Ba source includes at least one of Ba(NO3)2 and BaCl2.

[0101] According to a specific embodiment of the present application, the kind of the Sr source is not particularly limited, and as some specific examples, the Sr source includes at least one of Sr(NO3)2, SrCl2·6H2O.

[0102] According to a specific embodiment of the present application, the kind of the base is not particularly limited, and as some specific examples, the base includes at least one of NaOH, KOH, ammonia water.

[0103] According to a specific embodiment of the present application, the temperature of the mixing of the step S1 is 40-80℃, and as some specific examples, the temperature of the mixing of the step S1 can be 40℃, 50℃, 60℃, 70℃, 75℃, 80℃, etc.

[0104] According to a specific embodiment of the present application, the time of the mixing of the step S1 is 2-6h, and as some specific examples, the time of the mixing of the step S1 can be 2h, 3h, 4h, 5h, 6h, etc.

[0105] According to a specific embodiment of the present application, the temperature of the stirring of the step S1 is 40-80℃, and as some specific examples, the temperature of the stirring of the step S1 can be 40℃, 50℃, 60℃, 70℃, 75℃, 80℃, etc.

[0106] According to a specific embodiment of the present application, the time of the stirring of the step S1 is 2-6h, and as some specific examples, the time of the stirring of the step S1 can be 2h, 3h, 4h, 5h, 6h, etc.

[0107] According to a specific embodiment of the present application, the washing of the step S1 uses water and ethanol for alternate washing.

[0108] According to a specific embodiment of the present application, the washing of the step S1 uses water and ethanol for alternate washing for 1-5 times, and as some specific examples, the washing of the step S1 uses water and ethanol for alternate washing for 1, 2, 3, 4, or 5 times.

[0109] According to a specific embodiment of the present application, the amount of the base added is such that the pH of the mixed solution A is 8.5-11, and as some specific examples, the amount of the base added can be such that the pH of the mixed solution A is 8.5, 9, 9.5, 10, 10.5, or 11.

[0110] According to a specific embodiment of the present application, the temperature of the first calcination treatment is 600-1000℃, and as some specific examples, the temperature of the first calcination treatment can be 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, etc.

[0111] According to a specific embodiment of the present invention, the time of the first calcination treatment is 3 hours to 10 hours. As some specific examples, the time of the first calcination treatment can be 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc.

[0112] Step S2: adding the Cr source solution dropwise to the carrier powder obtained in step S1 for impregnation to obtain a first intermediate.

[0113] According to a specific embodiment of the present invention, the type of the Cr source is not particularly limited and may be at least one of Cr(NO3)3 or its hydrate, CrCl3 or its hydrate. As some specific examples, the Cr source includes at least one of Cr(NO3)3·9H2O and CrCl3·6H2O.

[0114] According to a specific embodiment of the present invention, the ratio of the mass of the Cr element in the Cr source solution to the mass of the carrier powder is (5-30):100. As some specific examples, the ratio of the mass of the Cr element in the Cr source solution to the mass of the carrier powder may be 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, etc.

[0115] According to a specific embodiment of the present invention, the immersion temperature of step S2 is 25°C-80°C. As some specific examples, the immersion temperature of step S2 may be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.

[0116] According to a specific embodiment of the present invention, the immersion time of step S2 is 2 hours to 6 hours. As some specific examples, the immersion time of step S2 can be 2 hours, 4 hours, 6 hours, etc.

[0117] According to a specific embodiment of the present invention, the type of the solvent in the Cr source solution is not particularly limited, and includes but is not limited to water.

[0118] According to a specific embodiment of the present invention, the immersion in step S2 is performed under ultrasonic conditions.

[0119] According to a specific embodiment of the present invention, the step S2 further includes filtering and drying after the impregnation is completed.

[0120] According to a specific embodiment of the present invention, step S2 is further filtered and dried after the impregnation is completed, the drying temperature is 80°C-110°C (for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C), and the drying time is 10h-24h (for example, it can be 10h, 12h, 15h, 20h, 22h, 24h).

[0121] Step S3: performing a second calcination treatment on the first intermediate under a N2 / O2 mixed atmosphere to obtain a second intermediate.

[0122] Specifically, the type of the reaction vessel used in the second calcination treatment is not particularly limited, and some specific examples include but are not limited to a tubular reactor.

[0123] According to a specific embodiment of the present invention, the volume fraction of O2 in the N2 / O2 mixed atmosphere is 1%-10%. As some specific examples, the volume fraction of O2 in the N2 / O2 mixed atmosphere may be 1%, 2%, 3%, 4%, 5%, 6%, 6.5%, 7%, 8%, 9%, 10%, etc.

[0124] According to a specific embodiment of the present invention, the temperature of the second calcination treatment is 300°C-500°C. As some specific examples, the temperature of the second calcination treatment may be 300°C, 350°C, 400°C, 450°C, 500°C, etc.

[0125] According to a specific embodiment of the present invention, the time of the second roasting treatment is 4 hours to 10 hours. As some specific examples, the time of the second roasting treatment can be 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc.

[0126] According to a specific embodiment of the present invention, the preparation method further comprises: before performing the second calcination treatment on the first intermediate, pressing the first intermediate into a shape.

[0127] Step S4: activating the second intermediate under a HF / N2 mixed atmosphere to obtain the supported chromium-based catalyst.

[0128] According to a specific embodiment of the present invention, the volume fraction of HF in the HF / N2 mixed atmosphere is 35%-70%. As some specific examples, the volume fraction of HF in the HF / N2 mixed atmosphere may be 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc.

[0129] According to a specific embodiment of the present invention, the temperature of the activation treatment is 200°C-400°C. As some specific examples, the temperature of the activation treatment may be 200°C, 250°C, 300°C, 350°C, 400°C, etc.

[0130] According to a specific embodiment of the present invention, the activation treatment time is 8h-24h. As some specific examples, the activation treatment time can be 8h, 10h, 12h, 15h, 16h, 20h, 22h, 24h, etc.

[0131] According to an embodiment of the present invention, the third aspect of the present invention provides the use of the supported chromium-based catalyst described in the first aspect or the supported chromium-based catalyst prepared according to the preparation method described in the second aspect in the fluorination reaction of C3 halocarbons.

[0132] According to an embodiment of the present invention, a fourth aspect of the present invention provides a method for fluorination of a C3 halogenated hydrocarbon, comprising:

[0133] contacting a first halogenated hydrocarbon, HF, and a supported chromium-based catalyst to perform a fluorination reaction to obtain a second halogenated hydrocarbon;

[0134] Wherein, the supported chromium-based catalyst is the supported chromium-based catalyst described in the first aspect or the supported chromium-based catalyst prepared according to the preparation method described in the second aspect.

[0135] The supported chromium-based catalyst provided by the present invention can be used as a catalyst for fluorination reaction and improves the conversion rate and selectivity of the fluorination reaction.

[0136] According to a specific embodiment of the present invention, the molar ratio of the first halogenated hydrocarbon to HF is 1:(5-20). As some specific examples, the molar ratio of the first halogenated hydrocarbon to HF can be 1:5, 1:10, 1:15, 1:20, etc.

[0137] According to a specific embodiment of the present invention, the type of the first halogenated hydrocarbon is not particularly limited. As some specific examples, the first halogenated hydrocarbon includes but is not limited to one of 1,1,1,3-tetrachloropropane (R250fb), 1,1,1,2,3-pentachloropropane (R240db), 1,1,1,3,3-pentachloropropane (R240fa), 1,1,2,3-tetrachloropropene (R1230xa), 1-chloro-3,3,3-trifluoropropene (R1233zd), and 2-chloro-3,3,3-trifluoropropene (R1233xf).

[0138] According to a specific embodiment of the present invention, the temperature of the fluorination reaction is 200° C.-400° C. As some specific examples, the temperature of the fluorination reaction can be 200° C., 300° C., 400° C., etc.

[0139] According to a specific embodiment of the present invention, the contact time of the fluorination reaction is 1s-100s. As some specific examples, the contact time of the fluorination reaction can be 1s, 5s, 10s, 20s, 50s, 100s, etc.

[0140] According to a specific embodiment of the present invention, the type of the second halogenated hydrocarbon is not particularly limited. As some specific examples, the second halogenated hydrocarbon includes but is not limited to one of 3,3,3-trifluoropropene (R1243zf), 2-chloro-3,3,3-trifluoropropene (R1233xf), 1-chloro-3,3,3-trifluoropropene (R1233zd), 1,3,3,3-tetrafluoropropene (R1234ze), and 2,3,3,3-tetrafluoropropene (R1234yf). Specifically, the second halogenated hydrocarbon can be used as a refrigerant, a foaming agent, a fire extinguishing agent, etc., and has the characteristics of zero ozone depletion potential (ODP) value and low global warming potential (GWP) value.

[0141] Below, the scheme of the present invention will be explained in conjunction with embodiment.It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.In the embodiment, if specific technology or conditions are not indicated, the technology or conditions described in the literature in this area or the product instructions are used.The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained by commercial purchase.

[0142] Example 1

[0143] This embodiment provides a supported chromium-based catalyst and a preparation method thereof, comprising the following steps:

[0144] (1) 500 g of Fe(NO3)3·9H2O and Ni(NO3)2·6H2O powders were weighed and dissolved in deionized water at a molar ratio of Fe to Ni of 2:1. The mixture was heated to 60°C in a water bath with constant stirring. Then, a NaOH aqueous solution was slowly added dropwise until the pH value was 10. The mixture was stirred for 3 h. After the solution was cooled to room temperature, the precipitate was filtered and washed alternately with deionized water and anhydrous ethanol for 3 times. The filter cake was moved to an oven and dried at 80°C for 16 h. The spinel ferrite carrier NiFe2O4 was obtained. The specific surface area was 279.9 m2 as determined by BET. 2 / g;

[0145] (2) Cr(NO3)3.9H2O powder was weighed in the amount of 20% of Cr relative to the mass of the carrier, dissolved in deionized water, and slowly added dropwise to the NiFe2O4 powder under the condition of ultrasonic oscillation in a water bath at 60°C. After the dropwise addition was completed, ultrasonic oscillation was continued for 3 h. Filtration was performed, and the filter cake was dried in an oven at 100°C for 10 h to obtain a first intermediate. The first intermediate was pressed into shape and then fed into a tubular reactor. The second intermediate was obtained by calcining the second intermediate particles in the tubular reactor at 400°C for 4 h in an O2 / N2 (O2 volume fraction of 6.5%) atmosphere. The NiFe2O4-supported chromium oxyfluoride catalyst was obtained by fluorination of the second intermediate particles in the tubular reactor at 350°C for 16 h by feeding in HF / N2 mixed gas (HF accounts for 45 vol%, and the balance is N2).

[0146] Example 2

[0147] The difference between this example and Example 1 is that in step (2), Cr(NO3)3.9H2O powder was weighed in the amount of 10% of Cr relative to the mass of the carrier, and dissolved in deionized water.

[0148] Example 3

[0149] The difference between this example and Example 1 is that in step (2), the O2 volume fraction in the O2 / N2 atmosphere is replaced from 6.5% to 2.5%.

[0150] Example 4

[0151] The difference between this example and Example 1 is that in step (1), Fe(NO3)3.9H2O, Ni(NO3)2.6H2O and Zn(NO3)2.6H2O powders were weighed in the molar ratio of Fe, Ni and Zn of 2:0.5:0.5, and a total of 500 g was prepared to prepare a Ni 0.5 Zn 0.5 Fe2O4 carrier, and the specific surface area determined by BET was 335.1 m 2 / g.

[0152] Example 5

[0153] The difference between this example and Example 4 is that in step (1), Fe(NO3)3.9H2O, Ni(NO3)2.6H2O and Sr(NO3)2 powders were weighed in the molar ratio of Fe, Ni and Sr of 2:0.5:0.5, and a total of 500 g was prepared to prepare a Ni 0.5 Sr 0.5 Fe2O4 carrier, and the specific surface area determined by BET was 315.9 m 2 / g.

[0154] Example 6

[0155] The difference between this example and Example 4 is only that in step (1), Fe(NO3)3·9H2O, Ni(NO3)2·6H2O and Ba(NO3)2 powders are weighed to a total of 500 g in a molar ratio of Fe, Ni, Ba of 2:0.6:0.4 to prepare Ni 0.6 Ba 0.4 Fe2O4 support with a specific surface area of 297.6 m 2 / g, determined by BET.

[0156] Comparative Example 1

[0157] The difference between this comparative example and Example 4 is only that in step (1), Fe(NO3)3·9H2O, Ni(NO3)2·6H2O and Zn(NO3)2·6H2O powders are weighed to a total of 500 g in a molar ratio of Fe, Ni, Zn of 2:0.2:0.8 to prepare Ni 0.2 Zn 0.8 Fe2O4 support with a specific surface area of 255.8 m 2 / g, determined by BET.

[0158] Comparative Example 2

[0159] The difference between this comparative example and Example 4 is only that in step (1), Ni(NO3)2·6H2O and Zn(NO3)2·6H2O powders are weighed to a total of 500 g in a molar ratio of Ni, Zn of 1:1 to prepare the support with a specific surface area of 100.3 m 2 / g, determined by BET. Finally, a fluorinated Ni-Zn composite oxide supported chromium catalyst is obtained.

[0160] Comparative Example 3

[0161] This comparative example provides a γ-AlF3 supported chromium-based catalyst and a preparation method thereof, which comprises the following steps:

[0162] Commercially available γ-Al2O3 with a specific surface area of 234.3 m 2 / g, determined by BET. 100 g of γ-Al2O3 is taken as the support, and Cr(NO3)3·9H2O powder is weighed in a mass fraction of 20% of Cr relative to the mass of the support and dissolved in deionized water. The solution is slowly added to the γ-Al2O3 in a water bath at 60°C, and after the addition is completed, stirring is continued for 3 h. The filter cake is dried in an oven at 100°C for 10 h to obtain precursor 1, which is then pressed into a shape. The precursor 2 is obtained by calcining the precursor 1 at 400°C for 4 h in an O2 / N2 (O2 volume fraction of 6.5%) atmosphere. The precursor 2 particles are placed in a tubular reactor, and the temperature is controlled at 350°C. HF / N2 mixed gas (HF accounts for 45 vol%, and the balance is N2) is introduced for fluorination for 16 h. Finally, a γ-AlF3 supported chromium oxyfluoride catalyst is obtained.

[0163] Comparative Example 4

[0164] This comparative example provides a doped chromium oxide catalyst and a preparation method thereof, wherein the preparation method comprises the following steps:

[0165] Weigh 500g of Cr(NO3)3·9H2O powder, and weigh Fe(NO3)3·9H2O and Ni(NO3)2·6H2O powders with molar contents of Fe and Ni relative to Cr of 5mol% and 2.5mol%, respectively. Dissolve the powders in deionized water with constant stirring, slowly add ammonia water to pH = 9, age for 1h, and filter. Place the filter cake in a 100°C oven to dry for 10h to obtain precursor 1, which is pressed into shape and placed in a tubular reactor and calcined at 400°C for 4h in an O2 / N2 (O2 volume fraction is 6.5%) atmosphere to obtain precursor 2. Precursor 2 particles are placed in a tubular reactor, the temperature is controlled at 350°C, and an HF / N2 mixed gas (HF accounts for 45vol%, the balance is N2) is introduced for fluorination for 16h to obtain a fluorinated iron-nickel doped chromium oxide catalyst.

[0166] Test Case

[0167] 1. Fluorination reaction of halocarbons

[0168] 20 mL of each of the catalysts prepared in the above examples and comparative examples was placed in a reactor, heated to 280° C. and purged with N 2 for 4 h. The reactor temperature was then adjusted and used for the following fluorination reaction of halogenated hydrocarbons:

[0169] Reaction (1):

[0170] The reaction temperature was 250°C, the molar ratio of anhydrous HF and R250fb was 10:1, and the contact time was 10 s.

[0171] Reaction (2):

[0172] The reaction temperature was 300°C, the molar ratio of anhydrous HF and R1230xa was 15:1, and the contact time was 10 s.

[0173] Reaction (3):

[0174] The reaction temperature was 350°C, the molar ratio of anhydrous HF and R1233xf was 15:1, and the contact time was 10 s.

[0175] Reaction (4):

[0176] The reaction temperature was 350°C, the molar ratio of anhydrous HF and R1233zd was 10:1, and the contact time was 10 s.

[0177] Reaction (5):

[0178] The reaction temperature was 320℃, the molar ratio of anhydrous HF and R240db was 20:1, and the contact time was 10s.

[0179] The results of gas chromatography analysis of the products of reactions (1)-(5) after water washing and alkali washing to remove HF are shown in the following tables. The results of reaction (1) are shown in Table 1, the results of reaction (2) are shown in Table 2, the results of reaction (3) are shown in Table 3, the results of reaction (4) are shown in Table 4, and the results of reaction (5) are shown in Table 5.

[0180] Table 1

[0181]

[0182]

[0183] Table 2

[0184]

[0185] Table 3

[0186]

[0187]

[0188] Table 4

[0189]

[0190] Table 5

[0191]

[0192]

[0193] Result analysis:

[0194] (1) Compared with other molar ratios of Fe, Ni, and Zn in the support (such as 2:0.2:0.8, 0:1:1 (see Comparative Examples 1 and 2)), the catalyst prepared using the molar ratio of Fe, Ni, and M (such as Zn or Sr or Ba) provided by the present application (2:x:(1-x), wherein 0.5≤x≤1, such as 2:1:0, 2:0.5:0.5, and 2:0.6:0.4 (see Examples 1-6)) has high catalytic activity, high substrate conversion rate, high selectivity of the target product, and long service life, and the substrate conversion rate and the selectivity of the target product do not decrease significantly after long-term use.

[0195] (2) Compared with other carriers (such as γ-AlF3, see Comparative Example 3), the catalyst prepared using the carrier provided by the present invention has high catalytic activity, high substrate conversion rate, high target product selectivity, and long service life. After long-term use, the substrate conversion rate and target product selectivity do not decrease significantly.

[0196] (3) Compared with other catalysts (such as the fluorinated iron-nickel doped chromium oxide catalyst of Comparative Example 4), the catalyst prepared using the carrier provided by the present invention has high catalytic activity, high substrate conversion rate, high target product selectivity, and long service life. After long-term use, the substrate conversion rate and target product selectivity do not decrease significantly.

[0197] (4) The present invention preferably incorporates an element M (such as Zn, Sr, or Ba) into the preparation of the catalyst, which is more conducive to improving the catalytic activity of the resulting catalyst and is more conducive to improving the substrate conversion rate and target product selectivity of the catalytic reaction.

[0198] 2. Catalyst Cr before and after reaction 6+ Changes and carbon deposit detection

[0199] The catalysts before and after reaction (4) were characterized by the following test methods:

[0200] ① Raman spectroscopy characterization of Cr before and after reaction 6+ Changes:

[0201] The RM1000 laser confocal Raman microscope was manufactured by Renishaw. The laser wavelength was 514.5 nm and the scanning range was 100–1800 cm.

[0202] Calculate 1000-1020cm before and after the reaction -1 The peak intensity I1 and 540-560cm -1 The ratio of the peak intensity I2 is I1 / I2, as shown in Table 6. Where I1 represents the CrO3 vibration peak, and I2 represents the α-Cr2O3 crystal phase vibration peak.

[0203] Table 6

[0204]

[0205]

[0206] Result analysis:

[0207] From the results in Table 6, we can see that the catalyst provided in the embodiment has a significant effect on Cr 6+ The loss phenomenon has been significantly improved.

[0208] ②Determination of carbon content:

[0209] Using a Shanghai Dekai Instruments HCS-140 infrared carbon and sulfur analyzer, the sample was heated and burned in a high-frequency induction furnace. The CO2 and SO2 gases released were then sent to the infrared detection system after dust removal and drying. The carbon content of the catalyst after 500 hours of reaction is shown in Table 7.

[0210] Table 7

[0211]

[0212] Result analysis:

[0213] It can be seen from Table 7 that the catalyst provided in the examples has a significant inhibitory effect on carbon deposition.

[0214] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0215] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A supported chromium-based catalyst, characterized in that The supported chromium-based catalyst comprises a carrier and chromium oxyfluoride; The carrier includes spinel nickel ferrite, whose chemical formula is M 1-x Ni x Fe2O4, wherein 0.5≤x≤1, and M includes at least one of Zn, Co, Cu, Mn, Mg, Ba, and Sr.

2. The supported chromium-based catalyst according to claim 1, characterized in that The mass ratio of chromium element to carrier in the chromium oxyfluoride is (5-30):100; Optionally, the specific surface area of ​​the carrier is 250m 2 / g-400m 2 / g.

3. A method for preparing a supported chromium-based catalyst according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: Step S1: mixing an Fe source, a Ni source, an optional M source and water, then adding alkali dropwise to obtain a mixed solution A, stirring, cooling, obtaining a precipitate, washing, drying, and performing a first calcination treatment to obtain a carrier powder; Step S2: adding the Cr source solution dropwise to the carrier powder obtained in step S1 for impregnation to obtain a first intermediate; Step S3: performing a second calcination treatment on the first intermediate under a N2 / O2 mixed atmosphere to obtain a second intermediate; Step S4: activating the second intermediate under a HF / N2 mixed atmosphere to obtain the supported chromium-based catalyst.

4. The preparation method according to claim 3, characterized in that The M source includes at least one of a Zn source, a Co source, a Cu source, a Mn source, a Mg source, a Ba source, and a Sr source; Optionally, the M source includes a nitrate or a hydrate of a nitrate, a chloride or a hydrate of a chloride, a sulfate or a hydrate of a sulfate, or an oxalate or a hydrate of an oxalate of at least one metal selected from the group consisting of Zn, Co, Cu, Mn, Mg, Ba, and Sr; Optionally, the Fe source includes at least one of Fe(NO3)3, Fe(NO3)3·9H2O, FeCl3, FeCl3·6H2O, and Fe2(SO4)3; Optionally, the Ni source includes at least one of Ni(NO3)2, Ni(NO3)2·6H2O, NiCl2, NiCl2·6H2O, and NiSO4; Optionally, the Zn source includes at least one of Zn(NO3)2, Zn(NO3)2·6H2O, ZnCl2, ZnCl2·6H2O, and ZnSO4; Optionally, the Co source includes at least one of Co(NO3)2, Co(NO3)2·6H2O, CoCl2, CoCl2·6H2O, CoSO4·7H2O, and CoC2O4·2H2O; Optionally, the Cu source includes at least one of Cu(NO3)2, Cu(NO3)2·3H2O, CuCl2, CuCl2·6H2O, CuSO4·5H2O, and CuC2O4; Optionally, the Mn source includes at least one of Mn(NO3)2, Mn(NO3)2·4H2O, MnCl2, MnCl2·4H2O, and MnSO4; Optionally, the Mg source includes at least one of Mg(NO3)2, Mg(NO3)2·6H2O, MgCl2, MgCl2·6H2O, and MgSO4; Optionally, the Ba source includes at least one of Ba(NO3)2 and BaCl2; Optionally, the Sr source includes at least one of Sr(NO3)2 and SrCl2·6H2O; Optionally, the base includes at least one of NaOH, KOH, and ammonia water.

5. The preparation method according to claim 3, characterized in that The amount of base added is such that the pH of the mixed solution A is 8.5-11; Optionally, the base is added in an amount such that the pH of the mixed solution A is 10; Optionally, the mixing temperature in step S1 is 40° C.-80° C.; Optionally, the mixing time in step S1 is 2h-6h; Optionally, the stirring temperature in step S1 is 40° C.-80° C.; Optionally, the stirring time in step S1 is 2h-6h; Optionally, the washing in step S1 is performed by alternating washing with water and ethanol; Optionally, the washing in step S1 is performed by alternating washing with water and ethanol for 1-5 times; Optionally, the temperature of the first calcination treatment is 600°C-1000°C; Optionally, the first calcination treatment is performed for 3 hours to 10 hours.

6. The preparation method according to claim 3, characterized in that The Cr source includes at least one of Cr(NO3)3 or its hydrate, CrCl3 or its hydrate; Optionally, the Cr source includes at least one of Cr(NO3)3·9H2O and CrCl3·6H2O; Optionally, the ratio of the mass of the Cr element in the Cr source solution to the mass of the carrier powder is (5-30):100; Optionally, the immersion temperature in step S2 is 25° C.-80° C.; Optionally, the immersion time in step S2 is 2h-6h; Optionally, the solvent in the Cr source solution includes water; Optionally, the immersion in step S2 is performed under ultrasonic conditions; Optionally, the step S2 further comprises filtering and drying after the impregnation is completed; Optionally, after the impregnation is completed, the step S2 further includes filtering and drying, the drying temperature is 80° C.-110° C., and the drying time is 10 h-24 h.

7. The preparation method according to claim 3, characterized in that The volume fraction of O2 in the N2 / O2 mixed atmosphere is 1%-10%; Optionally, the temperature of the second calcination treatment is 300°C-500°C; Optionally, the second calcination treatment time is 4h-10h; Optionally, the volume fraction of HF in the HF / N2 mixed atmosphere is 35%-70%; Optionally, the activation treatment temperature is 200°C-400°C; Optionally, the activation treatment time is 8h-24h.

8. Use of the supported chromium-based catalyst according to claim 1 or 2 or the supported chromium-based catalyst prepared according to the preparation method according to any one of claims 3 to 7 in the fluorination reaction of C3 halocarbons.

9. A method for fluorinating a C3 halogenated hydrocarbon, characterized in that: include: contacting a first halogenated hydrocarbon, HF, and a supported chromium-based catalyst to perform a fluorination reaction to obtain a second halogenated hydrocarbon; Wherein, the supported chromium-based catalyst is the supported chromium-based catalyst according to claim 1 or 2, or the supported chromium-based catalyst prepared according to the preparation method according to any one of claims 3-7.

10. The fluorination method according to claim 9, characterized in that The molar ratio of the first halogenated hydrocarbon to HF is 1:(5-20); Optionally, the first halogenated hydrocarbon comprises one of 1,1,1,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane, 1,1,1,3,3-pentachloropropane, 1,1,2,3-tetrachloropropene, 1-chloro-3,3,3-trifluoropropene, and 2-chloro-3,3,3-trifluoropropene; Optionally, the temperature of the fluorination reaction is 200°C-400°C; Optionally, the contact time of the fluorination reaction is 1s-100s; Optionally, the second halogenated hydrocarbon comprises one of 3,3,3-trifluoropropene, 2-chloro-3,3,3-trifluoropropene, 1-chloro-3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, and 2,3,3,3-tetrafluoropropene.

Images