Catalyst based on twelve-membered ring aluminophosphate molecular sieve, preparation method and long-chain alkane isomerization method

Abstract

The invention discloses a catalyst based on a twelve-membered ring aluminophosphate molecular sieve, a preparation method and a long-chain alkane isomerization method. The catalyst comprises the twelve-membered ring aluminophosphate molecular sieve, a noble metal active component and a metal oxide auxiliary active component. The twelve-membered ring aluminum phosphate molecule is selected from at least one of SAPO-5 (silicoaluminophosphate), MeAPO-5, SAPO-31 (silicoaluminophosphate) and MeAPO-31 (silicoaluminophosphate); the noble metal active component is selected from at least one of Pt and Pd; the metal oxide auxiliary agent is selected from at least one of SnO2 and TiO2. The preparation method comprises the following steps: loading the auxiliary agent on the twelve-membered ring aluminophosphate molecular sieve, roasting, loading the noble metal active component, roasting and reducing to obtain the target catalyst. Compared with the catalyst prepared in the prior art, the catalyst prepared by the method provided by the invention has higher activity and isomer yield in the isomerization reaction of long-chain n-alkanes.

Description

Technical Field

[0001] The present application relates to a catalyst based on dodecacyclic aluminophosphate molecular sieve, a preparation method thereof, and a method for isomerization of long-chain alkanes, belonging to the technical field of molecular sieve catalysts. Background Art

[0002] Bifunctional solid catalysts are widely used in the process of alkane hydroisomerization, which consists of a hydrogenation-dehydrogenation component and an acidic support. Among them, the hydrogenation-dehydrogenation component is mainly Group VIII metals such as Pt, Pd, Rh, Ir, and Ni, etc.; the acidic support can be divided into the following three categories: 1. Amorphous single metal oxides or composite oxides, such as Al2O3 treated with halides, SiO2 / Al2O3, superacid ZrO2 / SO4 2- 、WO3 / ZrO2, etc.; 2. Series of silicon-aluminum molecular sieves, such as Y, Beta, ZSM-5, etc.; 3. Series of aluminophosphate molecular sieves, such as SAPO-5, SAPO-11, SAPO-31, and SAPO-41, etc. Compared with amorphous oxides and superacids, molecular sieves show excellent performance in terms of shape selectivity, stability, anti-poisoning, and anti-coking ability. Therefore, isomerization catalysts with molecular sieves as carriers are widely used. Patent documents such as US5882505, US20040138051A1, US20050077209A1, CN1792451, CN1788844A, and CN101245260A have all described in detail the preparation methods of alkane hydroisomerization catalysts with molecular sieves as carriers.

[0003] Dodecacyclic aluminophosphate molecular sieve is a kind of synthetic molecular sieve, and its typical representatives are SAPO-5, MeAPO-5 (Me = Zn, Mg, Mn, Co, Cr, Cu, Cd or Ni), SAPO-31, MeAPO-31 (Me = Zn, Mg, Mn, Co, Cr, Cu, Cd or Ni), which have the characteristics of moderate acidity and one-dimensional straight channels, and are ideal carriers for shape-selective isomerization catalysts of long-chain alkanes.

[0004] According to the reaction mechanism of n-alkanes on bifunctional catalysts, the conversion of n-alkanes on the catalyst surface mainly undergoes three chemical reaction steps and two diffusion steps. The chemical reaction steps include alkane dehydrogenation reaction and olefin hydrogenation reaction on metal centers and isomerization / cracking reaction on acidic centers. The diffusion steps include the diffusion of n-olefins from metal centers to acidic centers and the diffusion of iso-olefins from acidic centers to metal centers. From the perspective of chemical reaction steps, the isomerization performance of bifunctional catalysts is affected by factors such as the metallicity (electronic properties, loading, and dispersion, etc.) of the catalyst, acidity (acid type, acid amount, and acid strength, etc.), and pore structure. In the alkane isomerization reaction, the metallicity of the catalyst can not only ensure the progress of alkane dehydrogenation reaction and olefin hydrogenation reaction, improve the reaction activity and isomer selectivity of the catalyst, but also inhibit the formation of carbon deposition and improve the stability of the catalyst. When the metallicity is insufficient to balance the acidity, the isomerization carbocations on acidic centers are prone to further isomerization or even cracking reactions, resulting in low isomer selectivity of the catalyst. For a long time, people often increase the number of metal active sites by increasing the metal loading and improving the dispersion, so as to maintain the balance with acidic sites, while little attention has been paid to improving the intrinsic activity of metal sites. Summary of the Invention

[0005] The object of the present invention is to provide a shape-selective isomerization catalyst based on dodecasil phosphoaluminate molecular sieve and its preparation method.

[0006] The present invention also relates to the application of the above catalyst in the isomerization reaction of long-chain n-alkanes.

[0007] Specifically, the present invention provides a shape-selective isomerization catalyst based on dodecasil phosphoaluminate molecular sieve, which enhances the hydrogenation / dehydrogenation performance of noble metals by metal oxide promoters SnO2 and TiO2, thereby obtaining excellent hydroisomerization performance.

[0008] According to one aspect of the present application, a catalyst based on dodecasil phosphoaluminate molecular sieve is provided, and the catalyst comprises an active component, a metal oxide, and a dodecasil phosphoaluminate molecular sieve;

[0009] The active component and the metal oxide are loaded on the dodecasil phosphoaluminate molecular sieve;

[0010] The active component is selected from Pt and / or Pd;

[0011] The metal oxide is selected from SnO2 and / or TiO2;

[0012] The dodecasil phosphoaluminate molecular sieve is selected from at least one of SAPO-5, MeAPO-5, SAPO-31, and MeAPO-31;

[0013] Among them, Me in the MeAPO-5 and MeAPO-31 is selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Cd or Ni, and the mass content of Me is 0.05 to 5 wt.%.

[0014] Optionally, Me in the MeAPO-5 and MeAPO-31 is selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Cd or Ni, and the mass content of Me is independently selected from any value of 0.05 wt.%, 0.1 wt.%, 0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.% or the range value between any two of the above.

[0015] Optionally, the acid amount of the twelve-membered ring aluminophosphate molecular sieve is 0.6 to 1.8 mmol(NH3) / g.

[0016] Optionally, the acid amount of the twelve-membered ring aluminophosphate molecular sieve is independently selected from any value of 0.6 mmol(NH3) / g, 0.7 mmol(NH3) / g, 0.8 mmol(NH3) / g, 0.9 mmol(NH3) / g, 1.0 mmol(NH3) / g, 1.1 mmol(NH3) / g, 1.2 mmol(NH3) / g, 1.3 mmol(NH3) / g, 1.4 mmol(NH3) / g, 1.5 mmol(NH3) / g, 1.6 mmol(NH3) / g, 1.7 mmol(NH3) / g, 1.8 mmol(NH3) / g or the range value between any two of the above.

[0017] Optionally, the acid amount of the twelve-membered ring aluminophosphate molecular sieve is 1.0 to 1.6 mmol(NH3) / g.

[0018] Optionally, in the catalyst, the content of the active component is 0.1 wt.% to 0.3 wt.%.

[0019] Optionally, in the catalyst, the content of the active component is independently selected from any value of 0.1 wt.%, 0.15 wt.%, 0.2 wt.%, 0.25 wt.%, 0.3 wt.% or the range value between any two of the above.

[0020] Optionally, in the catalyst, the content of the metal oxide is 0.1 wt.% to 10 wt.%.

[0021] Optionally, in the catalyst, the content of the metal oxide is independently selected from any value of 0.1 wt.%, 0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.% or a range value between any two of the above.

[0022] Optionally, in the catalyst, the content of the metal oxide is 0.4 wt.% to 5 wt.%.

[0023] Optionally, in the catalyst, the content of the metal oxide is independently selected from any value of 0.4 wt.%, 0.8 wt.%, 1 wt.%, 1.2 wt.%, 1.8 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.% or a range value between any two of the above.

[0024] Optionally, in the catalyst, the content of the dodecasil aluminophosphate molecular sieve is 95 wt.% to 99.5 wt.%.

[0025] Optionally, in the catalyst, the content of the dodecasil aluminophosphate molecular sieve is independently selected from any value of 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, 99 wt.%, 99.5 wt.% or a range value between any two of the above.

[0026] According to another aspect of the present application, there is provided a method for preparing the above-mentioned catalyst, and the preparation method includes the following steps:

[0027] (1) A mixture containing a metal oxide precursor and a dodecasil aluminophosphate molecular sieve is impregnated, dried I, and calcined I to obtain a dodecasil aluminophosphate molecular sieve loaded with a metal oxide;

[0028] (2) The active component precursor is loaded onto the dodecasil aluminophosphate molecular sieve loaded with the metal oxide in step (1) by electrostatic adsorption, dried II, calcined II, and reduced to obtain the catalyst.

[0029] Optionally, in the step (1), the metal oxide precursor is selected from at least one of tin chloride, stannous chloride, titanium tetrachloride, titanium tetrabromide, and titanium tetraiodide.

[0030] Optionally, the impregnation is equal-volume impregnation.

[0031] Optionally, in the step (1), the impregnation method is the equal-volume impregnation method, and by measuring the pore volume of the carrier, an equal volume of an aqueous solution or hydrochloric acid solution of the promoter precursor is inhaled.

[0032] Optionally, the temperature of the first drying is 50°C to 200°C, and the time of the first drying is 0.5 to 24 h.

[0033] Optionally, the atmosphere for the first calcination is an oxygen-containing atmosphere.

[0034] Optionally, the oxygen-containing atmosphere is pure oxygen, oxygen-nitrogen mixture or oxygen-argon mixture.

[0035] Optionally, the temperature of the first calcination is 300°C to 800°C, and the time of the first calcination is 0.1 to 48 h.

[0036] Optionally, the temperature of the first calcination is 400°C to 600°C, and the time of the first calcination is 0.5 to 24 h.

[0037] Optionally, in the step (2), the active component precursor is selected from at least one of chloroplatinic acid, ammonium chloroplatinate, ammonium chloropalladate, chloropalladic acid, ammonium chloropalladite, and ammonium chloroplatinate.

[0038] Optionally, in the step (2), in the electrostatic adsorption, the pH value of the electrostatic adsorption mixed solution is 1 to 6.

[0039] Optionally, in the electrostatic adsorption, the pH value regulator is selected from at least one of hydrochloric acid, sulfuric acid, ammonia water, liquid ammonia, methylamine, nitric acid, ethylamine, and oxalic acid.

[0040] Optionally, in the step (2), the method of electrostatic adsorption is to soak the carrier in a solution containing the precursor of the loaded substance, adjust the charged property of the carrier surface, and selectively adsorb the positively or negatively charged loaded substance ions.

[0041] Optionally, in the step (2), in the method of electrostatic adsorption, the pH value of the electrostatic adsorption mixed solution is adjusted by adding acids such as hydrochloric acid, nitric acid, oxalic acid, sulfuric acid, and bases such as ammonia water, liquid ammonia, methylamine, and ethylamine.

[0042] Optionally, in the step (2), in the method of electrostatic adsorption, the dodecacyclic aluminophosphate molecular sieve after loading the metal oxide promoter is soaked in the noble metal precursor solution for 2 to 12 h.

[0043] Optionally, in the step (2), in the method of electrostatic adsorption, after soaking in the noble metal precursor solution, the solid is filtered and washed with deionized water 1 to 6 times until the eluate is neutral.

[0044] Optionally, in the step (2), the temperature of the second drying is 50°C to 200°C, and the time of the second drying is 0.5 to 24 h.

[0045] Optionally, the temperature of the second calcination is 400°C to 600°C, and the time of the first calcination is 0.5 to 24 h.

[0046] Optionally, the reducing atmosphere is hydrogen.

[0047] Optionally, the gas flow rate of the hydrogen is 2 to 200 mL / min / g 催化剂 。

[0048] Optionally, the reduction temperature is 200°C to 400°C, and the reduction time is 2 to 8 h.

[0049] Optionally, the reduction temperature is 250°C to 350°C, and the reduction time is 4 to 8 h.

[0050] According to another aspect of the present application, a method for isomerizing long-chain alkanes is provided, and the method includes: using a catalyst in the long-chain alkane isomerization reaction;

[0051] The catalyst is selected from the catalysts described above;

[0052] The long-chain alkane is selected from C8-C50 long-chain alkanes.

[0053] Optionally, the conditions for the long-chain alkane isomerization reaction are:

[0054] The feed volume space velocity is 0.5 to 5 h -1 , the hydrogen-oil ratio (mol / mol) is 5 to 50, the reaction temperature is 200 to 400°C, and the reaction pressure is 0.1 to 10 MPa.

[0055] Optionally, the reaction temperature is 280 to 350°C.

[0056] The catalyst provided by the present invention can be widely applied to the processing processes of petroleum fractions, biomass, and Fischer-Tropsch synthesis products, such as isomerization for pour point reduction, isomerization dewaxing, and other processes.

[0057] The above catalyst preparation method provided by the present invention: First, a metal oxide promoter is loaded on a dodecacyclic aluminophosphate molecular sieve, and then a noble metal active component is loaded after calcination, and the target catalyst is obtained through calcination and reduction, including the following steps:

[0058] (1) Loading a promoter precursor on a dodecacyclic aluminophosphate molecular sieve by an impregnation method, drying and then calcining in an oxygen-containing atmosphere to obtain a dodecacyclic aluminophosphate molecular sieve loaded with a metal oxide promoter;

[0059] (2) Further loading a noble metal precursor on the dodecacyclic aluminophosphate molecular sieve loaded with a metal oxide promoter obtained in step (1) by an electrostatic adsorption method, drying and then calcining in an oxygen-containing atmosphere, and reducing at 200 to 400°C in hydrogen for 2 to 8 h to prepare the shape-selective isomerization catalyst.

[0060] Optionally, the metal oxide promoter is selected from at least one of SnO2 and TiO2.

[0061] The beneficial effects that can be achieved by this application include:

[0062] 1) The noble metal content in the shape-selective isomerization catalyst provided by this application is 0.1 wt% to 0.3 wt%, which is significantly lower than the noble metal loading of about 0.5 wt% in traditional hydroisomerization catalysts;

[0063] 2) The shape-selective isomerization catalyst provided by this application has higher activity, isomer selectivity, and isomer yield in the alkane isomerization reaction;

[0064] 3) The preparation process of the catalyst provided by this application is simple and easy to implement. Specific Embodiments

[0065] The following describes this application in detail with reference to examples, but this application is not limited to these examples.

[0066] Unless otherwise specified, the raw materials in the examples of this application are all purchased through commercial channels.

[0067] Conversion (Conv) = C 所有产物 / (C 所有产物 +C 剩余正十四烷 ) × 100%;

[0068] Selectivity (S) = C 异十四烷 / C 所有产物 × 100%;

[0069] Yield (Y) = Conv × S × 100%.

[0070] Comparative Example 1

[0071] Take 50 g of template-removed SAPO-5 molecular sieve, and its acid amount is 1.2 mmol(NH3) / g. Immerse 50 g of the above carrier with 25 mL of H2PtCl6 solution containing 0.01 g / mL of Pt, air-dry naturally and dry at 120 °C for 4 h, calcine at 500 °C for 4 h, and then use hydrogen with a flow rate of 60 mL / min / g 催化剂 to reduce at 400 °C for 4 h to obtain a 0.5 wt% Pt / SAPO-5 catalyst. The catalytic reaction evaluation results are shown in Table 1.

[0072] Comparative Example 2

[0073] Take 50 g of the template-removed MgAPO-5 molecular sieve, with an acid amount of 1.0 mmol(NH3) / g. Impregnate 50 g of the above carrier with 25 mL of an H2PtCl6 solution containing 0.01 g / mL of Pt, air-dry naturally and dry at 120 °C for 4 h, calcine at 500 °C for 4 h, and then use hydrogen with a flow rate of 60 mL / min / g 催化剂 to reduce at 400 °C for 4 h to obtain a 0.5 wt% Pt / MgAPO-5 catalyst. The catalytic reaction evaluation results are shown in Table 1.

[0074] Comparative Example 3

[0075] Take 50 g of the template-removed SAPO-31 molecular sieve, with an acid amount of 1.4 mmol(NH3) / g. Impregnate 50 g of the above carrier with 25 mL of an H2PtCl6 solution containing 0.01 g / mL of Pt, air-dry naturally and dry at 120 °C for 4 h, calcine at 500 °C for 4 h, and then use hydrogen with a flow rate of 80 mL / min / g 催化剂 to reduce at 400 °C for 4 h to obtain a 0.5 wt% Pt / SAPO-31 catalyst. The catalytic reaction evaluation results are shown in Table 1.

[0076] Comparative Example 4

[0077] Take 50 g of the template-removed ZnAPO-31 molecular sieve, with an acid amount of 1.7 mmol(NH3) / g. Impregnate 50 g of the above carrier with 25 mL of an H2PdCl6 solution containing 0.01 g / mL of Pd, air-dry naturally and dry at 120 °C for 4 h, calcine at 500 °C for 4 h, and then use hydrogen with a flow rate of 80 mL / min / g 催化剂 to reduce at 400 °C for 4 h to obtain a 0.5 wt% Pd / ZnAPO-31 catalyst. The catalytic reaction evaluation results are shown in Table 1.

[0078] Example 1

[0079] Step 1: Take 50 g of the SAPO-5 molecular sieve in Comparative Example 1, impregnate it with 25 mL of an SnCl4 solution containing 0.012 g / mL of Sn, then air-dry naturally and dry at 120 °C for 4 h, and calcine at 500 °C for 4 h for standby; Step 2: Dissolve H2PtCl6 in deionized water, dilute it to a concentration of 0.0005 g / mL containing Pt, and measure 200 ml of this H2PtCl6 aqueous solution; Step 3: Immerse the 50 g of the SAPO-5 loaded with the tin oxide promoter obtained in Step 1 in the 200 ml of the H2PtCl6 aqueous solution prepared in Step 2, adjust its pH value to 2.6 with hydrochloric acid, soak for 6 h, filter and wash with deionized water 4 times until the eluate is neutral, air-dry the obtained solid naturally and dry at 120 °C for 4 h, calcine at 450 °C for 4 h, and then use hydrogen with a flow rate of 60 mL / min / g催化剂 The hydrogen gas was reduced at 400 °C for 4 h to prepare a 0.2 wt% Pt - 0.6 wt% SnO2 / SAPO - 5 catalyst. The evaluation results of the catalytic reaction are shown in Table 1.

[0080] Example 2

[0081] Step 1: Take 50 g of the MgAPO - 5 molecular sieve in Comparative Example 2, impregnate it with 25 mL of a SnCl2 solution containing 0.024 g / mL of Sn, then air - dry it naturally and dry it at 120 °C for 4 h, and calcine it at 450 °C for 6 h for standby; Step 2: Dissolve (NH4)2PtCl6 in deionized water, dilute it to a concentration containing 0.0004 g / mL of Pt, and measure 200 mL of this (NH4)2PtCl6 aqueous solution; Step 3: Immerse the 50 g of MgAPO - 5 loaded with tin oxide promoter obtained in Step 1 in the 200 mL of (NH4)2PtCl6 aqueous solution prepared in Step 2, adjust its pH value to 2.4 with hydrochloric acid, soak for 4 h, filter and wash it 4 times with deionized water until the eluate is neutral, air - dry the obtained solid naturally and dry it at 120 °C for 4 h, calcine it at 430 °C for 6 h, and then use hydrogen gas with a flow rate of 60 mL / min / g 催化剂 to reduce it at 380 °C for 4 h to prepare a 0.16 wt% Pt - 1.2 wt% SnO2 / MgAPO - 5 catalyst. The evaluation results of the catalytic reaction are shown in Table 1.

[0082] Example 3

[0083] Step 1: Take 50 g of the SAPO - 31 molecular sieve in Comparative Example 3, impregnate it with 25 mL of a TiCl4 solution containing 0.06 g / mL of Ti, then air - dry it naturally and dry it at 120 °C for 4 h, and calcine it at 500 °C for 4 h for standby; Step 2: Dissolve H2PtCl6 in deionized water, dilute it to a concentration containing 0.0005 g / mL of Pt, and measure 200 mL of this H2PtCl6 aqueous solution; Step 3: Immerse the 50 g of SAPO - 31 loaded with titanium oxide promoter obtained in Step 1 in the 200 mL of H2PtCl6 aqueous solution prepared in Step 2, adjust its pH value to 1.2 with hydrochloric acid, soak for 3 h, filter and wash it 5 times with deionized water until the eluate is neutral, air - dry the obtained solid naturally and dry it at 120 °C for 4 h, calcine it at 480 °C for 4 h, and then use hydrogen gas with a flow rate of 100 mL / min / g 催化剂 to reduce it at 400 °C for 4 h to prepare a 0.2 wt% Pt - 3 wt% TiO2 / SAPO - 31 catalyst. The evaluation results of the catalytic reaction are shown in Table 1.

[0084] Example 4

[0085] Step 1: Take 50 g of the ZnAPO-31 molecular sieve in Comparative Example 2, impregnate it with 25 mL of a TiBr4 solution containing 0.024 g / mL of Ti, then air-dry it naturally and dry it at 120 °C for 4 h, and calcine it at 420 °C for 6 h for standby; Step 2: Prepare an H2PdCl6 solution containing 0.0004 g / mL of Pd; Step 3: Immerse 50 g of the ZnAPO-31 loaded with titanium oxide promoter obtained in Step 1 in 200 ml of the H2PdCl6 solution prepared in Step 2, adjust its pH value to 1.4 with ammonia water, soak for 4 h, filter and wash it 4 times with deionized water until the eluate is neutral, and the obtained solid is air-dried naturally and dried at 120 °C for 4 h, and calcined at 430 °C for 6 h, and then reduced with hydrogen at a flow rate of 60 mL / min / g 催化剂 to obtain a 0.16 wt% Pd-1.2 wt% TiO2 / ZnAPO-31 catalyst. The catalytic reaction evaluation results are shown in Table 1.

[0086] Catalyst performance evaluation of Example 5

[0087] The catalyst evaluation was carried out in a stainless steel tube fixed-bed reactor. Take 10 mL of the prepared catalyst and install it in the reactor. Heat it to the reaction temperature under a hydrogen atmosphere, and feed the raw material oil n-tetradecane for reaction. The products were analyzed by gas chromatography. Reaction conditions: reaction temperature 280 - 350 °C, 3 MPa, n-tetradecane feed volume space velocity 1.0 h -1 , and the hydrogen-oil ratio (mol / mol) was 15.

[0088] Table 1. Catalyst evaluation results in comparative examples and examples

[0089]

[0090]

[0091] As can be seen from Table 1, compared with the catalysts prepared by the conventional method in the comparative examples, the catalysts prepared by the present method in Examples 1 - 4 can obtain higher activity, higher isomer selectivity and isomer yield in the hydroisomerization reaction of long-chain alkanes.

[0092] The above 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 art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases, and all belong to the scope of the technical solution.

Claims

1. A catalyst based on dodecacyclic aluminophosphate molecular sieve, characterized in that, The catalyst includes an active component, a metal oxide, and a dodecacyclic aluminophosphate molecular sieve; The active component and the metal oxide are supported on the dodecacyclic aluminophosphate molecular sieve; The active component is selected from Pt and / or Pd; The metal oxide is selected from SnO2 and / or TiO2; The dodecacyclic aluminophosphate molecular sieve is selected from at least one of SAPO-5, MeAPO-5, SAPO-31, and MeAPO-31; Wherein, Me in MeAPO-5 and MeAPO-31 is selected from at least one of Zn, Mg, Mn, Co, Cr, Cu, Cd, or Ni, and the mass content of Me is 0.05 - 5 wt.%; 2. The catalyst according to claim 1, characterized in that, The acid amount of the dodecacyclic aluminophosphate molecular sieve is 0.6 - 1.8 mmol(NH3) / g; Preferably, the acid amount of the dodecacyclic aluminophosphate molecular sieve is 1.0 - 1.6 mmol(NH3) / g; Preferably, in the catalyst, the content of the active component is 0.1 wt.% - 0.3 wt.%; Preferably, in the catalyst, the content of the metal oxide is 0.1 wt.% - 10 wt.%; Preferably, in the catalyst, the content of the metal oxide is 0.4 wt.% - 5 wt.%; Preferably, in the catalyst, the content of the dodecacyclic aluminophosphate molecular sieve is 95 wt.% - 99.5 wt.%; 3. A method for preparing the catalyst according to any one of claims 1 to 2, characterized in that, The preparation method includes the following steps: (1) Impregnate, dry I, and calcine I a mixture containing a metal oxide precursor and a dodecacyclic aluminophosphate molecular sieve to obtain a dodecacyclic aluminophosphate molecular sieve loaded with a metal oxide; (2) Load an active component precursor on the dodecacyclic aluminophosphate molecular sieve loaded with the metal oxide in step (1) by electrostatic adsorption, dry II, calcine II, and reduce to obtain the catalyst.

4. The preparation method according to claim 3, characterized in that, In the step (1), the metal oxide precursor is selected from at least one of tin chloride, stannous chloride, titanium tetrachloride, titanium tetrabromide, and titanium tetraiodide; Preferably, the impregnation is equal-volume impregnation; Preferably, the temperature of dry I is 50°C - 200°C, and the time of dry I is 0.5 - 24 h; Preferably, the temperature of calcine I is 300°C - 800°C, and the time of calcine I is 0.1 - 48 h; Preferably, the temperature of calcine I is 400°C - 600°C, and the time of calcine I is 0.5 - 24 h; 5. The preparation method according to claim 3, characterized in that, In the step (2), the active component precursor is selected from at least one of chloroplatinic acid, ammonium chloroplatinate, ammonium chloropalladate, chloropalladic acid, ammonium chloropalladite, and ammonium chloroplatinate; 6. The preparation method according to claim 3, characterized in that, In the step (2), in the electrostatic adsorption, the pH value of the electrostatic adsorption mixed solution is 1 - 6; Preferably, the pH value regulator in the electrostatic adsorption is selected from at least one of hydrochloric acid, sulfuric acid, ammonia water, liquid ammonia, methylamine, nitric acid, ethylamine, and oxalic acid; 7. The preparation method according to claim 3, characterized in that, In the step (2), the temperature of dry II is 50°C - 200°C, and the time of dry II is 0.5 - 24 h; Preferably, the temperature of calcine II is 400°C - 600°C, and the time of calcine I is 0.5 - 24 h; Preferably, the reducing atmosphere is hydrogen; Preferably, the gas flow rate of the hydrogen is 2 to 200 mL / min / g 催化剂 ; Preferably, the reduction temperature is 200°C to 400°C, and the reduction time is 2 to 8 h; Preferably, the reduction temperature is 250°C to 350°C, and the reduction time is 4 to 8 h.

8. A method for isomerization of long-chain alkanes, characterized in that, The method includes: using the catalyst in the isomerization reaction of long-chain alkanes; The catalyst is selected from the catalysts described in any one of claims 1 to 2; The long-chain alkanes are selected from C8-C50 long-chain alkanes.

9. The method according to claim 8, wherein, The conditions for the isomerization reaction of long-chain alkanes are: The feed volume space velocity is 0.5 - 5 h -1 , the hydrogen / oil ratio (mol / mol) is 5 - 50, the reaction temperature is 200 - 400 °C, and the reaction pressure is 0.1 - 10 MPa.

10. The method according to claim 9, wherein, The reaction temperature is 280 to 350°C.

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