Non-noble metal-based bifunctional catalyst as well as preparation method and application thereof

Abstract

The invention discloses a non-noble metal-based bifunctional catalyst as well as a preparation method and application thereof. The non-noble metal-based bifunctional catalyst comprises a carrier and an active component, the carrier is a hydrogen type ZSM-48 molecular sieve; the active component comprises an active element; the active element is selected from at least one of Fe, Co and Ni; the dispersity of the active component is 5.5 to 40 percent. The catalyst is prepared by the following steps: preparing an aluminum source, a template agent, inorganic alkali, a metal precursor and water into a mother solution, then adding a ZSM-48 molecular sieve matrix into the mother solution, and carrying out hydrothermal crystallization at a certain temperature. According to the bifunctional catalyst, synchronous construction of a metal site and an acid site is realized by using a one-step recrystallization strategy, and the bifunctional catalyst prepared by the method has the advantages of high metal dispersity and good stability. The catalyst shows excellent catalytic activity and target product yield in a chain alkane isomerization reaction.

Description

Technical Field

[0001] The present application relates to a non-noble metal-based bifunctional catalyst, a preparation method thereof, and an application thereof, belonging to the technical field of catalytic chemistry. Background Art

[0002] Bifunctional catalytic materials with zeolite materials as carriers and metal species complexed are used in multiple catalytic fields, especially in consecutive reactions that require different catalytic active sites, such as: the hydrodeoxygenation process of biomass platform molecules, the CO 2 hydrocarbon production process, and the hydroisomerization process of wax oil. The "metal-acidity" balance in bifunctional catalysts is the key to constructing excellent alkane isomerization catalysts. Its metal components include two categories: noble metals (Pt, Pd, Ru, etc.) and non-noble metals (Ni, Co, Mo, etc.). Among them, noble metals Pt and Pd have been widely used industrially due to their excellent dehydrogenation / hydrogenation performance, but they have always faced problems of tight supply and high costs due to their scarcity. Therefore, the development of non-noble metal-based bifunctional catalysts has attracted much attention. However, since the dehydrogenation / hydrogenation performance of non-noble metals is far inferior to that of noble metals, a much higher loading amount is required to achieve the balance between acid sites and metal centers. The weak polarization ability of non-noble metals results in a weak interaction between them and the carrier, and metal sintering is likely to occur at a higher loading amount, leading to a decrease in catalytic ability [C. Dai, K. Du, C. Song, X. Guo, 2020, 6791-133.]. Therefore, designing and developing a catalyst preparation method with highly dispersed metals and good anti-sintering ability is the key to promoting the industrial application of non-noble metal-based catalysts.

[0003] In view of the defects of non-noble metal-based catalysts, such as difficult dispersion and easy sintering, a large number of modification methods have been developed. For example, through metal doping (CN116590053A), increasing the surface area of the carrier (CN103787368A), etc. Introducing metals in-situ during the zeolite crystallization process and utilizing the confinement effect of zeolite micropores or intercrystalline (intracrystalline) mesopores is an effective means to improve the metal dispersion and anti-sintering performance. Exploring a simple and economical in-situ synthesis strategy is an extremely important topic. Summary of the Invention

[0004] The purpose of the present application is to develop a non-noble metal-based bifunctional catalytic material. This method realizes the synchronous construction of metal sites and acid sites of the bifunctional catalyst through one-step recrystallization, and the preparation process is simple. Moreover, the obtained non-noble metal-based bifunctional catalyst has the characteristics of high metal dispersion and strong anti-sintering ability.

[0005] In one aspect of the present application, a non-noble metal-based bifunctional catalyst is provided, and the non-noble metal-based bifunctional catalyst includes a carrier and an active component;

[0006] The carrier is a hydrogen-form ZSM-48 molecular sieve;

[0007] The active component includes active elements;

[0008] The active elements are selected from at least one of Fe, Co, and Ni;

[0009] The dispersion degree of the active component is 5.5-40%;

[0010] Optionally, the dispersion degree of the active component is independently selected from any value of 5.5%, 10%, 15%, 19%, 25%, 27%, 30%, 31%, 35%, 40% or the range value between any two of the above;

[0011] Optionally, the catalyst has an ellipsoidal crystal structure or a rod bundle crystal.

[0012] Optionally, the particle size of the active component is 2 nm to 20 nm.

[0013] Optionally, the particle size of the active component is independently selected from any value of 2 nm, 2.5 nm, 3 nm, 5 nm, 10 nm, 15 nm, 20 nm or the range value between any two of the above;

[0014] Optionally, the mass content of the active component in the non-noble metal-based bifunctional catalyst is 1-10 wt%, wherein the mass of the active component is based on the mass of the active element.

[0015] Optionally, the mass content of the active component in the non-noble metal-based bifunctional catalyst is independently selected from any value of 1 wt%, 2 wt%, 3 wt%, 3.48 wt%, 4.99 wt%, 5.03 wt%, 6 wt%, 7.28 wt%, 8 wt%, 9 wt%, 10 wt% or the range value between any two of the above;

[0016] Optionally, the silica-alumina ratio (SiO 2 to Al 2 O 3 molar ratio) of the ZSM-48 molecular sieve ≥ 30, or the ZSM-48 molecular sieve is a pure silica molecular sieve.

[0017] Optionally, the non-noble metal-based bifunctional catalyst has a hydrogen-form ZSM-48 molecular sieve and metal species (Fe, Co, Ni). The non-noble metal-based bifunctional catalyst is to construct the acidic sites and metal sites required for the bifunctional catalyst in one step through a recrystallization hydrothermal synthesis strategy, and the silica-alumina ratio (SiO 2 to Al 2 O 3 molar ratio) of the ZSM-48 molecular sieve is 30-∞;

[0018] The mass content of the metal species in the non-noble metal-based bifunctional catalyst is 1-10 wt%.

[0019] The loading amount of the metal species is calculated based on the atomic weight of the metal in the metal precursor.

[0020] The metal species are selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, iron nitrate, iron chloride, and iron sulfate.

[0021] In another aspect of the present application, a preparation method of the above non-noble metal-based bifunctional catalyst is provided, and the above technical problems are solved by using appropriate raw materials and finely adjusting the raw material composition and adopting the recrystallization hydrothermal crystallization method.

[0022] The preparation method includes:

[0023] Mix the ZSM-48 molecular sieve matrix with the mother liquor, and after aging II and hydrothermal crystallization II, obtain the bifunctional catalyst raw powder, and obtain the non-noble metal-based bifunctional catalyst through calcination and ion exchange;

[0024] Among them, the mother liquor includes aluminum source II, template agent II, inorganic base II, metal precursor, and water II.

[0025] Optionally, the ZSM-48 molecular sieve matrix is a silica-aluminum or all-silica ZSM-48 molecular sieve.

[0026] Optionally, the preparation method of the ZSM-48 molecular sieve matrix includes:

[0027] Mix the raw materials containing silicon source I, inorganic base I, and template agent I with water I, then carry out aging I, hydrothermal crystallization I, washing, drying, and calcination to obtain the ZSM-48 molecular sieve matrix.

[0028] Optionally, the silicon source I is selected from at least one of fumed silica, silica sol, tetraethyl orthosilicate, and water glass;

[0029] The inorganic base I is selected from at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, lithium hydroxide, and ammonia water;

[0030] The concentration of the ammonia water is 25 wt%;

[0031] The template agent I is selected from at least one of hexamethylammonium bromide, hexamethylammonium chloride, hexamethylammonium hydroxide, and 1,6-hexanediamine.

[0032] Optionally, the molar ratio of the inorganic base I to the silicon source I is 0.02-0.6;

[0033] The molar ratio of the template agent I to the silicon source I is 0.02 to 0.5;

[0034] The molar ratio of the water I to the silicon source I is 15 to 60;

[0035] Among them, the molar amount of the silicon source I is calculated based on the molar amount of SiO 2 in the selected silicon source I;

[0036] The molar amount of the template agent I is calculated based on the molar amount of hexamethonium in the template agent I or the molar amount of 1,6-hexanediamine;

[0037] The molar amount of the inorganic base I is calculated based on the hydroxide in the inorganic base I.

[0038] Optionally, the molar ratio of the inorganic base I to the silicon source I is independently selected from any value of 0.02, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or the range value between any two of the above.

[0039] Optionally, the molar ratio of the template agent I to the silicon source I is independently selected from any value of 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 or the range value between any two of the above.

[0040] Optionally, the molar ratio of the water I to the silicon source I is independently selected from any value of 15, 30, 45, 60 or the range value between any two of the above.

[0041] Optionally, the raw material further contains an aluminum source I; the aluminum source I is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite, and aluminum chloride;

[0042] The molar ratio of the silicon source I to the aluminum source I ≥ 50;

[0043] The molar amount of the aluminum source I is calculated based on the molar amount of Al 2 O 3 in the aluminum source I.

[0044] Optionally, the temperature of the aging I is 25 to 80 °C;

[0045] The time of the aging I is 2 to 8 h.

[0046] Optionally, the temperature of the aging I is independently selected from any value of 25 °C, 30 °C, 40 °C, 45 °C, 50 °C, 60 °C, 70 °C, 80 °C or the range value between any two of the above.

[0047] Optionally, the time of the aging I is independently selected from any value of 2 h, 4 h, 6 h, 8 h or the range value between any two of the above.

[0048] Optionally, the hydrothermal crystallization I is dynamic crystallization;

[0049] The temperature of the hydrothermal crystallization I is 140 - 200 °C;

[0050] The time of the hydrothermal crystallization I is 48 - 120 h.

[0051] Optionally, the temperature of the hydrothermal crystallization I is independently selected from any value of 140 °C, 160 °C, 170 °C, 200 °C or the range value between any two of the above.

[0052] Optionally, the time of the hydrothermal crystallization I is independently selected from any value of 48 h, 64 h, 72 h, 100 h, 120 h or the range value between any two of the above.

[0053] Optionally, the dynamic crystallization I is carried out in a autoclave reactor in a rotary oven, and the rotation speed of the rotary oven is 10 - 80 r / min.

[0054] After the crystallization is completed, through filtration, washing, and calcination at 500 °C for 6 h to remove the template agent, the molecular sieve mother body is obtained.

[0055] Optionally, the mass ratio of the mother liquor to the ZSM-48 molecular sieve mother body is 5 - 70.

[0056] Optionally, the mass ratio of the mother liquor to the ZSM-48 molecular sieve mother body is independently selected from any value of 5, 10, 20, 30, 40, 50, 60, 70 or the range value between any two of the above.

[0057] Optionally, the aluminum source II is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudoboehmite, or aluminum chloride.

[0058] Optionally, the inorganic base II is selected from at least one of sodium hydroxide, potassium hydroxide, or lithium hydroxide.

[0059] Optionally, the template agent II is selected from at least one of hexamethylenediammonium bromide, hexamethylenediammonium chloride, or hexamethylenediammonium hydroxide.

[0060] Optionally, the metal precursor is selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, iron nitrate, iron chloride, or iron sulfate.

[0061] Optionally, in the mother liquor, the concentration of the aluminum source II is 0.001 - 0.1 mol / L, calculated as the concentration of Al ions;

[0062] In the mother liquor, the concentration of the template agent II is 0.06 - 0.45 mol / L;

[0063] In the mother liquor, the concentration of the inorganic base II is 0.1 to 0.8 mol / L, calculated based on the concentration of OH - .

[0064] Optionally, the concentration of the aluminum source II is independently selected from any value of 0.001 mol / L, 0.0019 mol / L, 0.0025, 0.055 mol / L, 0.085 mol / L, 0.1 mol / L or the range value between any two of the above.

[0065] Optionally, the concentration of the template agent II is independently selected from any value of 0.06 mol / L, 0.1 mol / L, 0.15 mol / L, 0.25 mol / L, 0.45 mol / L or the range value between any two of the above.

[0066] Optionally, the concentration of the inorganic base II is independently selected from any value of 0.1 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.4 mol / L, 0.52 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L or the range value between any two of the above.

[0067] Optionally, the addition amount of the metal precursor is 1 wt% to 15 wt% of the ZSM-48 molecular sieve matrix, calculated based on the metal content in the metal precursor.

[0068] Optionally, the addition amount of the metal precursor is independently selected from any value of 1 wt%, 3 wt%, 4 wt%, 5 wt%, 8 wt%, 9 wt%, 10 wt%, 12 wt%, 15 wt% or the range value between any two of the above.

[0069] Optionally, the temperature of the aging II is 30 to 80 °C;

[0070] The time of the aging II is 2 to 8 h.

[0071] Optionally, the temperature of the aging II is independently selected from any value of 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C or the range value between any two of the above.

[0072] Optionally, the time of the aging II is independently selected from any value of 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h or the range value between any two of the above.

[0073] Optionally, the temperature of the hydrothermal crystallization II is 120 to 200 °C; the time of the hydrothermal crystallization II is 48 to 120 h.

[0074] Optionally, the temperature of the hydrothermal crystallization II is independently selected from any value of 120 °C, 140 °C, 160 °C, 180 °C, 200 °C or a range value between any two of the above.

[0075] Optionally, the time of the hydrothermal crystallization II is independently selected from any value of 48 h, 60 h, 72 h, 84 h, 96 h, 108 h, 120 h or a range value between any two of the above.

[0076] Optionally, the hydrothermal crystallization II is dynamic crystallization under autogenous pressure;

[0077] The dynamic crystallization means that it is carried out in a kettle reactor in a rotary oven;

[0078] The rotation speed of the rotary oven is 10 - 80 r / min.

[0079] Optionally, the temperature of the calcination is 400 - 600 °C;

[0080] The time of the calcination is 1 - 8 h.

[0081] Optionally, the temperature of the calcination is independently selected from any value of 400 °C, 450 °C, 500 °C, 520 °C, 550 °C, 600 °C or a range value between any two of the above.

[0082] Optionally, the time of the calcination is independently selected from any value of 1 h, 2 h, 4 h, 6 h, 8 h or a range value between any two of the above.

[0083] Optionally, the obtained catalyst raw powder is calcined in an air atmosphere at 550 °C for 6 h to remove the template agent, and then the bifunctional catalyst is obtained through ion exchange.

[0084] In another aspect of the present application, there is provided an application of the above non-noble metal-based bifunctional catalyst in the catalytic isomerization reaction of linear alkanes, and the application includes:

[0085] Under the condition of hydrogen I, a raw material containing linear alkanes is contacted with the pretreated non-noble metal-based bifunctional catalyst to carry out an isomerization reaction;

[0086] Among them, the linear alkanes are selected from at least one of normal linear alkanes of C 6 ~C 18 .

[0087] Optionally, the conditions of the pretreatment are: the non-noble metal-based bifunctional catalyst is reduced and activated in a hydrogen II atmosphere;

[0088] The temperature of the reduction activation is 450 - 600 °C, and the time of the reduction activation is 1 - 5 h.

[0089] Optionally, the temperature of the reduction activation is independently selected from any value of 450 °C, 500 °C, 550 °C, 600 °C or a range value between any two of the above.

[0090] Optionally, the time of the reduction activation is independently selected from any value of 1 h, 2 h, 3 h, 4 h, 5 h or a range value between any two of the above.

[0091] Optionally, the temperature of the isomerization reaction is 200-370 °C;

[0092] The pressure of the isomerization reaction is 0-4 MPa;

[0093] The mass space velocity of hydrogen I is 0.5-10 h -1 ;

[0094] In the isomerization reaction, the volume ratio of hydrogen I to the linear alkane is 10-400.

[0095] Optionally, the temperature of the isomerization reaction is independently selected from any value of 200 °C, 250 °C, 290 °C, 300 °C, 305 °C, 350 °C, 370 °C or a range value between any two of the above.

[0096] Optionally, the pressure of the isomerization reaction is independently selected from any value of 0 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa or a range value between any two of the above.

[0097] Optionally, the mass space velocity of hydrogen I is independently selected from 0.5 h -1 , 1 h -1 , 2 h -1 , 4 h -1 , 6 h -1 , 8 h -1 , 10 h -1 or a range value between any two of the above.

[0098] Optionally, the volume ratio of hydrogen I to the linear alkane is independently selected from any value of 10, 50, 100, 150, 200, 250, 300, 350, 400 or a range value between any two of the above.

[0099] Optionally, as a specific implementation manner, the application includes: the above non-noble metal-based catalyst is subjected to reduction activation in an H 2 atmosphere, and after activation, the temperature is reduced to the reaction temperature, and then a raw material containing a linear alkane is contacted with the linear alkane isomerization catalyst for reaction.

[0100] The beneficial effects that can be produced by this application include:

[0101] (1) This application provides a synthesis method for in-situ synthesizing a non-noble metal-based bifunctional catalyst, which realizes the synchronous construction of acid sites and metal sites of the bifunctional catalyst through a recrystallization strategy in one step.

[0102] (2) The non-noble metal-based bifunctional catalyst prepared in this application has the advantages of high metal dispersion and strong anti-sintering ability.

[0103] (3) The method used in this application realizes the one-step construction of metal sites and acid sites, with a simple and economical process.

[0104] (4) The bifunctional catalyst prepared by this method has the advantages of high metal dispersion and good stability. It exhibits excellent catalytic activity and target product yield in the isomerization reaction of linear alkanes. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Figure 1 XRD patterns of the bifunctional catalysts prepared in Examples 1-5

[0106] Figure 2 SEM image of the bifunctional catalyst prepared in Example 1, with a scale bar of 1 μm.

[0107] Figure 3 TEM image of the bifunctional catalyst prepared in Example 1, with a scale bar of 20 nm.

[0108] Figure 4 SEM image of the bifunctional catalyst prepared in Example 3, with a scale bar of 2 μm. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0109] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0110] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0111] The specific information of various substances used in the embodiments is as follows:

[0112] Silica sol (Qingdao Ocean Chemical Co., Ltd., 30 wt% SiO 2 );

[0113] Fumed silica (Macklin, 95 wt% SiO 2 );

[0114] Tetraethyl orthosilicate (TEOS) (Comin Chemical, >98 wt%);

[0115] Al 2 (SO 4 )3 ·18H 2 O (Sinopharm Group, 98 wt%);

[0116] Al(NO 3 ) 3 ·9H 2 O (Sinopharm Group, 99 wt%);

[0117] Pseudoboehmite (Maclean, 66% wt Al 2 O 3 , 33 wt% H 2 O);

[0118] NaOH (Sinopharm Group, >96 wt%);

[0119] KOH (Kermel, 85 wt%);

[0120] HMBr (Aladdin, 98 wt%);

[0121] HMCl (Aladdin, 98 wt%)

[0122] n-Dodecane (Aladdin, 99.8 wt%)

[0123] High-purity hydrogen gas (Dalian Institute of Chemical Physics, 99.9 wt%)

[0124] Al 2 O 3 (Sinopharm Group, analytical reagent)

[0125] Deionized water (self-made).

[0126] In the examples of this application, the conversion rate and yield are calculated as follows:

[0127]

[0128]

[0129] In the examples of this application, XRD tests were carried out using a Bruker D8 Advance X-ray diffractometer from Germany, TEM tests were carried out using a JEM-2100F instrument, and SEM tests were carried out using a JSM-7800F instrument.

[0130] Preparation Example 1

[0131] Preparation of ZSM-48 molecular sieve mother body:

[0132] Under stirring conditions, 0.16 g of Al 2 (SO 4 ) 3 ·18H 2O, 1.01 g HMBr, and 0.78 g NaOH are dissolved in 37.29 g H 2 O. After complete dissolution, 18.26 g of silica sol is added dropwise under stirring conditions. The initial gel is aged by stirring at 45 °C for 4 h, transferred to a stainless-steel autoclave, placed in a rotary oven, and hydrothermally crystallized at 170 °C and 60 r / min for 60 h. After the crystallization is completed, it is quenched to room temperature with cold water, and the ZSM-48 zeolite parent is obtained through filtration, washing, drying, and calcination.

[0133] According to the above ratio and synthesis steps, it can be synthesized in an equal proportion by scale-up.

[0134] Preparation Example 2

[0135] Preparation of ZSM-48 zeolite parent:

[0136] Under stirring conditions, 3.49 g of HDA and 0.21 g of NaOH are dissolved in 54 g of H 2 O. After complete dissolution, 6.00 g of fumed silica is added dropwise under stirring conditions. The initial gel is aged by stirring at 40 °C for 4 h, transferred to a stainless-steel autoclave, placed in a rotary oven, and hydrothermally crystallized at 160 °C and 60 r / min for 72 h. After the crystallization is completed, it is quenched to room temperature with cold water, and the ZSM-48 zeolite parent is obtained through filtration, washing, drying, and calcination.

[0137] According to the above ratio and synthesis steps, it can be synthesized in an equal proportion by scale-up.

[0138] Example 1

[0139] 2.0 g of NaOH, 0.25 g of Al 2 (SO 4 ) 3 ·18H 2 O, 4.35 g of HMBr, and 0.74 g of Ni(NO 3 ) 2 are dissolved in 120 g of water to form a mother liquor. 6.00 g of the parent ZSM-48 zeolite obtained in Preparation Example 1 is added to the mother liquor. It is aged under stirring at 30 °C for 3 h, transferred to a 200 ml stainless-steel autoclave, placed in a rotary oven, and hydrothermally crystallized at 160 °C and 60 r / min for 96 h. After the crystallization is completed, it is quenched to room temperature with cold water, and the sodium-type catalyst raw powder is obtained through filtration, washing, and drying. The XRD pattern of this catalyst raw powder is as Figure 1 shown, which is a pure-phase ZSM-48 zeolite, and no diffraction peaks attributable to metal Ni species are found. From the SEM image ( Figure 2 ), it can be seen that the catalyst is in the shape of ellipsoidal crystals. From the TEM image ( Figure 3)It can be seen that metallic Ni is in a highly dispersed state with a diameter of approximately 2.5 nm. The dispersion of metal particles in the catalyst was tested by CO pulse chemisorption, and the dispersion of metallic Ni was obtained as 30%.

[0140] The original catalyst powder was calcined in air atmosphere at 520 °C for 4 h and ion-exchanged with 1 mol / L ammonium chloride solution at 90 °C for 3 h to obtain the desired hydrogen form catalyst. The Ni loading of metallic Ni was determined by XRF to be 4.99 wt%.

[0141] Example 2

[0142] 2.0 g of NaOH, 0.25 g of Al 2 (SO 4 ) 3 ·18H 2 O, 4.35 g of HMBr, 0.52 g of Ni(NO 3 ) 2 were dissolved in 120 g of water to form a mother liquor. 6.00 g of the parent ZSM-48 molecular sieve obtained in Preparation Example 1 was added to the mother liquor. It was aged for 3 h under stirring at 30 °C, transferred to a 200 ml stainless steel autoclave, placed in a rotary oven, and hydrothermally crystallized at 160 °C and 60 r / min for 96 h. After the crystallization was completed, it was quenched to room temperature with cold water, and the sodium form catalyst powder was obtained through filtration, washing, and drying. The XRD pattern of this catalyst powder is as Figure 1 shown, being a pure phase ZSM-48 molecular sieve, and no diffraction peaks attributed to metallic Ni species were found. The catalyst morphology was similar to that of the example, and metallic Ni was highly dispersed spherical particles with a diameter of approximately 2 nm. The dispersion of metal particles in the catalyst was tested by CO pulse chemisorption, and the dispersion of metallic Ni was obtained as 35%.

[0143] The original catalyst powder was calcined in air atmosphere at 550 °C for 2 h and ion-exchanged with 1 mol / L ammonium chloride solution at 90 °C for 3 h to obtain the desired hydrogen form catalyst. The Ni loading of metallic Ni was determined by XRF to be 3.48 wt%.

[0144] Example 3

[0145] 1.2 g of NaOH, 0.15 g of Al 2 (SO 4 ) 3 ·18H 2 O, 4.35 g of HMBr, 0.74 g of Ni(NO 3 ) 2Prepare a mother liquor by dissolving it in 120 g of water. Weigh 6.00 g of the parent ZSM-48 molecular sieve obtained in Preparation Example 2 and add it to the mother liquor. Age for 3 h under stirring conditions at 30 °C, transfer it to a 200 ml stainless steel autoclave, place it in a rotary oven, and hydrothermally crystallize at 160 °C and 60 r / min for 96 h. After the crystallization is completed, quickly cool it to room temperature with cold water, and obtain the sodium-type catalyst precursor powder through filtration, washing, and drying. The XRD pattern of this catalyst precursor powder is as Figure 1 shown, which is a pure-phase ZSM-48 molecular sieve, and no diffraction peaks attributed to metal Ni species are found. The SEM image ( Figure 4 ) shows that the morphology of the catalyst is rod-bundle-shaped crystals, and the metal Ni is highly dispersed spherical particles with a diameter of about 5.0 nm. The dispersion of the metal particles in the catalyst is tested by CO pulse chemisorption, and the dispersion of metal Ni is obtained as 27%.

[0146] Calcine the catalyst precursor powder in an air atmosphere at 500 °C for 6 h and ion-exchange it with 1 mol / L ammonium chloride solution at 90 °C for 3 h to obtain the required hydrogen-type catalyst. The Ni loading of the metal is determined by XRF to be 5.03 wt%.

[0147] Example 4

[0148] Dissolve 1.2 g of NaOH, 0.15 g of Al 2 (SO 4 ) 3 ·18H 2 O, 4.35 g of HMBr, and 0.52 g of Ni(NO 3 ) 2 in 120 g of water to prepare a mother liquor. Weigh 6.00 g of the parent ZSM-48 molecular sieve obtained in Preparation Example 2 and add it to the mother liquor. Age for 3 h under stirring conditions at 30 °C, transfer it to a 200 ml stainless steel autoclave, place it in a rotary oven, and hydrothermally crystallize at 160 °C and 60 r / min for 96 h. After the crystallization is completed, quickly cool it to room temperature with cold water, and obtain the sodium-type catalyst precursor powder through filtration, washing, and drying. The XRD pattern of this catalyst precursor powder is as Figure 1 shown, which is a pure-phase ZSM-48 molecular sieve, and no diffraction peaks attributed to metal Ni species are found. The catalyst morphology is similar to that of Example 3, and the metal Ni is highly dispersed spherical particles with a diameter of about 3.0 nm. The dispersion of the metal particles in the catalyst is tested by CO pulse chemisorption, and the dispersion of metal Ni is obtained as 31%.

[0149] Calcine the catalyst precursor powder in an air atmosphere at 500 °C for 6 h and ion-exchange it with 1 mol / L ammonium chloride solution at 90 °C for 3 h to obtain the required hydrogen-type catalyst. The Ni loading of the metal is determined by XRF to be 5.03 wt%.

[0150] Example 5

[0151] Dissolve 2.5 g of NaOH, 0.25 g of Al 2 (SO 4 ) 3 ·18H 2 O, 4.35 g of HMBr, 1.04 g of Ni(NO 3 ) 2 in 120 g of water to prepare a mother liquor. Weigh 6.00 g of the parent ZSM-48 molecular sieve obtained in Preparation Example 1 and add it to the mother liquor. Age for 3 h under stirring conditions at 30 °C, transfer it to a 200 ml stainless steel autoclave, place it in a rotary oven, and hydrothermally crystallize at 160 °C and 60 r / min for 96 h. After the crystallization is completed, quickly cool it to room temperature with cold water, and obtain the sodium-form catalyst precursor powder through filtration, washing, and drying. The XRD pattern of this catalyst precursor powder is as Figure 1 shown, which is a pure-phase ZSM-48 molecular sieve, and no diffraction peaks attributed to metal Ni species are found. The catalyst morphology is similar to that of Example 1, and the metal Ni is highly dispersed spherical particles with a diameter of about 3.0 nm. The dispersion of metal particles in the catalyst is tested by CO pulse chemisorption, and the dispersion of metal Ni is obtained as 19%.

[0152] Calcine the catalyst precursor powder in an air atmosphere at 500 °C for 6 h and ion-exchange it with 1 mol / L ammonium chloride solution at 90 °C for 3 h to obtain the required hydrogen-form catalyst. The metal Ni loading of it is determined by XRF to be 7.28 wt%.

[0153] Verification of catalytic performance:

[0154] The non-noble metal-based bifunctional catalysts obtained in Examples 1 to 5 are ion-exchanged and calcined to obtain hydrogen-form catalysts. Then, they are tableted and crushed into 20-40 mesh particles for standby.

[0155] The catalytic performance of the catalyst is evaluated by the hydroisomerization reaction of n-dodecane. The reactant raw material is 99.8 wt% n-dodecane. Before the reaction, the catalyst is activated at 550 °C for 3 h in an atmospheric-pressure hydrogen atmosphere. After the temperature is lowered to the reaction temperature, the pressure is adjusted to 2.0 MPa, and then n-dodecane is introduced into the reaction system with a double plunger pump to start the reaction. During the reaction, the volume ratio of hydrogen to n-dodecane is maintained at 10.

[0156] The results are shown in Table 1.

[0157] Table 1 Catalytic performance of the catalysts in Examples 1 to 5

[0158]

[0159] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the relevant art, without departing from the technical solution of the present application, making some changes or modifications using the technical content disclosed above is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A non-noble metal-based bifunctional catalyst, characterized in that, the non-noble metal-based bifunctional catalyst comprises a carrier and an active component; the carrier is a hydrogen-type ZSM-48 molecular sieve; the active component comprises active elements; the active elements are selected from at least one of Fe, Co, and Ni; the dispersion of the active component is 5.5-40%.

2. The non-noble metal-based bifunctional catalyst according to claim 1, characterized in that, the catalyst has an ellipsoidal crystal structure or a rod bundle-like crystal; preferably, the particle size of the active component is 2 nm-20 nm.

3. The non-noble metal-based bifunctional catalyst according to claim 1, characterized in that, the mass content of the active component in the non-noble metal-based bifunctional catalyst is 1-10 wt%, wherein the mass of the active component is calculated based on the mass of the active elements; The silica-to-alumina ratio (SiO 2 to Al 2 O 3 molar ratio) of the ZSM-48 molecular sieve is not less than 30, or the ZSM-48 molecular sieve is a pure silica molecular sieve.

4. A preparation method of the non-noble metal-based bifunctional catalyst according to any one of claims 1-3, characterized in that, the preparation method comprises: mixing the ZSM-48 molecular sieve mother body with the mother liquor, followed by aging II and hydrothermal crystallization II to obtain the bifunctional catalyst raw powder, and then obtaining the non-noble metal-based bifunctional catalyst through calcination and ion exchange; wherein, the mother liquor comprises an aluminum source II, a template agent II, an inorganic base II, a metal precursor, and water II.

5. The preparation method according to claim 4, characterized in that, the preparation method of the ZSM-48 molecular sieve mother body comprises: mixing the raw materials containing a silicon source I, an inorganic base I, and a template agent I with water I, followed by aging I and hydrothermal crystallization I to obtain the ZSM-48 molecular sieve mother body; preferably, the silicon source I is selected from at least one of fumed silica, silica sol, tetraethyl orthosilicate, and water glass; the inorganic base I is selected from at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, lithium hydroxide, and ammonia water; the template agent I is selected from at least one of hexamethylammonium bromide, hexamethylammonium chloride, hexamethylammonium hydroxide, and 1,6-hexanediamine; preferably, the molar ratio of the inorganic base I to the silicon source I is 0.02-0.6; the molar ratio of the template agent I to the silicon source I is 0.02-0.5; the molar ratio of water I to the silicon source I is 15-60; Among them, the molar amount of the silicon source I is calculated based on the molar amount of SiO 2 in the selected silicon source I; the molar amount of the template agent I is calculated based on the molar amount of hexamethylammonium in the template agent I or the molar amount of 1,6-hexanediamine; the molar amount of the inorganic base I is calculated based on the hydroxide in the inorganic base I; preferably, the raw materials further contain an aluminum source I; the aluminum source I is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite, and aluminum chloride; preferably, the molar ratio of the silicon source I to the aluminum source I is ≥50; The molar amount of the aluminum source I is calculated based on the molar amount of Al 2 O 3 in the aluminum source I.

6. The preparation method according to claim 5, characterized in that, the temperature of the aging I is 25-80 °C; the time of the aging I is 2-8 h; preferably, the hydrothermal crystallization I is dynamic crystallization; the temperature of the hydrothermal crystallization I is 140-200 °C; the time of the hydrothermal crystallization I is 48-120 h.

7. The preparation method according to claim 4, characterized in that, The mass ratio of the mother liquor to the ZSM-48 molecular sieve matrix is 5 to 70; Preferably, the aluminum source II is selected from at least one of aluminum nitrate, aluminum sulfate, sodium aluminate, pseudo-boehmite, or aluminum chloride; Preferably, the inorganic base II is selected from at least one of sodium hydroxide, potassium hydroxide, or lithium hydroxide; Preferably, the template agent II is selected from at least one of hexamethylenediammonium bromide, hexamethylenediammonium chloride, or hexamethylenediammonium hydroxide; Preferably, the metal precursor is selected from at least one of nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride, iron nitrate, iron chloride, or iron sulfate; Preferably, in the mother liquor, the concentration of the aluminum source II is 0.001 to 0.1 mol / L, calculated as the concentration of Al ions; In the mother liquor, the concentration of the template agent II is 0.06 to 0.45 mol / L; In the mother liquor, the concentration of the inorganic base II is 0.1 to 0.8 mol / L, calculated based on the concentration of OH - . Preferably, the addition amount of the metal precursor is 1 wt% to 15 wt% of the ZSM-48 molecular sieve matrix, calculated based on the metal content in the metal precursor.

8. According to the preparation method described in claim 4, wherein, the temperature of the second aging is 30 to 80 °C; the time of the second aging is 2 to 8 h; Preferably, the temperature of the second hydrothermal crystallization is 120 to 200 °C; the time of the second hydrothermal crystallization is 48 to 120 h; Preferably, the temperature of the calcination is 400 to 600 °C; the time of the calcination is 1 to 8 h.

9. An application of the non-noble metal-based bifunctional catalyst described in any one of claims 1 to 3 in the isomerization reaction of linear alkanes, wherein, the application includes: Under the condition of hydrogen I, the raw material containing linear alkanes contacts with the pretreated non-noble metal-based bifunctional catalyst to undergo an isomerization reaction; Among them, the chain alkane is selected from at least one of normal chain alkanes having C 6 ~C 18 .

10. According to the application described in claim 9, wherein, the condition of the pretreatment is: the non-noble metal-based bifunctional catalyst is reduced and activated in a hydrogen II atmosphere; the temperature of the reduction activation is 450 to 600 °C, and the time of the reduction activation is 1 to 5 h; Preferably, the temperature of the isomerization reaction is 200 to 370 °C; the pressure of the isomerization reaction is 0 to 4 MPa; The mass space velocity of the hydrogen I is 0.5 to 10 h -1 ; In the isomerization reaction, the volume ratio of hydrogen I to linear alkanes is 10 to 400.

Images