A multilayer core-shell structured catalyst, a preparation method and use thereof

Abstract

The application discloses a multilayer core-shell structure catalyst, which comprises an acidic spherical inner core and a multilayer spherical outer shell. The application also discloses a preparation method of the multilayer core-shell structure catalyst and an application of the multilayer core-shell structure catalyst in catalyzing a biomass raw material to prepare an oxygen-free precursor of RJ-4 or JP-10 in one step.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to multilayer core-shell structure catalysts, their preparation methods, and their use in the synthesis of high-density fuel precursors. Background Technology

[0002] RJ-4 (bridged tetrahydromethyldicyclopentadiene dimer) was the first petroleum-based high-density liquid fuel synthesized artificially and used in the Talos missile. With increasing focus on fossil resources, various biomass methods for synthesizing RJ-4 have also been reported. The literature (ChemSusChem 2011, 4, 465-469) reports the preparation of methylcyclopentene methanol from linalool using the development of an organically coordinated noble metal, rhodium, followed by the dehydration condensation of methylcyclopentene methanol under an acidic catalyst to prepare the RJ-4 precursor. However, linalool here is a plant metabolite with limited sources. The literature (Green Chem. 2020, 22, 7765-7768.) reports that 2,5-hexanedione was first prepared by selective hydrogenation and deoxygenation ring-opening of 5-hydroxymethylfurfural under the action of Ni2P / mordenite catalyst, and then methylcyclopentenone was prepared by aldehyde condensation under alkaline catalyst. Then, methylcyclopentenol was prepared from methylcyclopentenone by selective hydrogenation and deoxygenation, and finally methylcyclopentenol was dehydrated and condensed under the action of acidic catalyst to synthesize a mixture of RJ-4 and methylcyclohexadiene trimer. The literature (ChemSusChem 2011, 4, 465-469) reports a method using 2,5-hexanedione as a starting material, which generates 3-methyl-2-cyclopenten-1-one via a base-catalyzed aldol condensation reaction. This is then selectively reduced to 3-methyl-2-cyclopenten-1-ol using [RuCl2(PPh3)3 / NH2(CH2)2NH2 / KOH], followed by dehydration condensation under AlPO4 / MgSO4 to prepare the RJ-4 precursor. It is evident that current biomass RJ-4 synthesis is either limited by the availability of raw materials, or, although the raw materials are widely available, requires multiple reaction steps to convert them into the RJ-4 precursor product.

[0003] JP-10 (hanging tetrahydrodicyclopentadiene) has a higher energy density (0.94 g / mL), better thermal stability, and a lower freezing point than traditional aviation fuels. Traditional JP-10 is mainly prepared by dimerization, hydrogenation, and isomerization of cyclopentadiene derived from petroleum refining, limiting the availability of raw materials. Recently, biomass JP-10 synthesis has also been developed. Literature reports a method using an alkaline catalyst to catalyze the rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone, followed by selective hydrogenation and deoxygenation of 4-hydroxycyclopent-2-enone to prepare 1,3-cyclopentadiol. 1,3-cyclopentadiol is then dehydrated to cyclopentadiene, which subsequently undergoes a self-Diels-Alder reaction to generate a cyclopentadiene dimer. Finally, the cyclopentadiene dimer is hydrogenated and isomerized to a bridged tetrahydrodicyclopentadiene dimer. In other words, the process from furfuryl alcohol to the JP-10 precursor requires four steps (Angew. Chem. Int.). (Ed. 2019, 58, 12154–12158; Shaanxi University of Technology, 2023. DOI: 10.27733 / d.cnki.gsxlg.2023.000292.); The estimated cost of JP-10 obtained by this synthesis method is less than $5600 / ton. Moreover, with the expected price of furfuryl alcohol falling to $400 / ton, JP-10 could reach $2547 / ton, far lower than the current market price of $7091 / ton for petroleum-based JP-10. It is evident that the synthesis of biomass JP-10 currently requires multiple reaction steps.

[0004] Currently, a wide variety of catalysts are used to synthesize RJ-4 and JP-10 from biomass feedstocks. The synthesis of RJ-4 precursors from cellulose-derived 2,5-hexanedione mainly involves multiple steps, each using a different catalyst with distinctly different properties, necessitating the separation and purification of the reaction products at each step. For example, the literature (Green Chem. 2020, 22, 7765-7768.) uses alkaline catalysts such as Mg–Zr–O, MgO, TiO2, Al2O3, Mg–Al–O, K3PO4, and NaOH in water and / or toluene solvents to first synthesize methylcyclopentenone from 2,5-hexanedione, and then methylcyclopentenone is reacted in NaBH4 / Ce 3+In a methanol system, methylcyclopentenol is selectively hydrogenated to synthesize methylcyclopentenol, which is then dehydrated and condensed under an acidic molecular sieve catalyst to generate the RJ-4 precursor. Literature (ChemSusChem 2021, 14, 339–343) describes the synthesis of methylcyclopentenone from 2,5-hexanedione using KOH as a catalyst, followed by selective reduction of methylcyclopentenone to methylcyclopentenol using RuCl2[P(C6H5)3]3, and finally dehydration condensation under the catalysis of AlPO4 and MgSO4 to prepare the RJ-4 precursor. The synthesis of the JP-10 precursor from furfuryl alcohol, a hemicellulose-derived feedstock, also involves multiple steps, requiring product separation and purification before each step, with each step using distinctly different catalysts. For example, (Angew. Chem. Int. Ed. 2019, 58, 12154–12158) reported the conversion of furfuryl alcohol to 4-hydroxy-cyclopenten-2-one using CaO catalysis, followed by selective reduction of 4-hydroxy-cyclopenten-2-one to cyclopentanediol using lanthanum, niobium, and nickel, and finally the dehydration condensation of 4-hydroxy-cyclopenten-2-one to cyclopentanediol using HUSY molecular sieve catalysis to prepare the JP-10 precursor.

[0005] In summary, all reported biomass synthesis of RJ-4 or JP-10 currently employs multi-step methods, involving multiple intermediate product separation and purification processes, as well as the application of various catalysts, sometimes even homogeneous catalysts, leading to difficulties in product separation and purification, and catalyst recovery. The final hydrodeoxygenation reaction is subject to extremely harsh conditions due to the presence of carbonyl groups. In reality, the cost of biomass synthesis of RJ-4 or JP-10 mainly stems from raw materials, process energy consumption, and catalysts, as the current routes involve numerous steps, each requiring separation and purification, consuming significant amounts of energy. Furthermore, the multi-step reaction places high demands on equipment.

[0006] The development of highly efficient catalysts can significantly reduce process energy consumption and equipment requirements. Core-shell structured catalysts have attracted widespread attention in the field of catalysts because they can combine multiple functions of catalysts to catalyze tandem reactions. Currently developed core-shell structured catalysts typically use SiO2, zeolite, CeO2, Al2O3, etc., as the shell layer, and the preparation methods include sol-gel method, microemulsion method, physical coating method, precipitation method, self-assembly method, atomic layer deposition method, etc. Patents CN118002194A, CN117983289A, CN110064399A, CN117884131A, CN117328096A, CN113394417A, CN106953104A, CN109603848A, CN105797749A, as well as master's and doctoral dissertations and journals, such as: Journal of Fuel Chemistry (Chinese and English), 2024, 52(03):353-361.DOI:10.19906 / j.cnki.JFCT.2023072, China Environmental Science, 20 Journals such as 24,44(01):193-201.DOI:10.19674 / j.cnki.issn1000-6923.20230908.018 and Journal of Chemical Industry and Engineering, 2023,74(06):2458-2467 have reported the synthesis of three-layer core-shell catalysts. The core and shell may involve metal alloys, metal oxides, carbon layers, silicon dioxide, aluminum oxide, etc. However, as catalysts, such multi-layer core-shell structures generally have the problem of large mass transfer resistance. Moreover, these reports do not show core-shell catalysts with an acidic core, a metal oxide intermediate layer, and an alkaline outer shell.

[0007] In summary, the existing technologies have the following problems: 1. The reaction of biomass as a raw material to obtain RJ-4 or JP-10 precursors involves a multi-step process. Each step requires product separation, purification, and transfer, resulting in product waste and the use of multiple solvents and equipment, making the operation cumbersome. 2. The reaction of biomass as a raw material to obtain RJ-4 or JP-10 precursors uses multiple different catalysts, increasing operational complexity. 3. The precursors of biomass as a raw material to obtain RJ-4 or JP-10 contain oxygen, requiring harsh conditions for hydrogenation deoxygenation to obtain the final RJ-4 or JP-10 product. 4. The multi-layered core-shell structure catalysts used have high mass transfer resistance.

[0008] The present invention is proposed to solve the above problems. Summary of the Invention

[0009] This invention discloses for the first time a multi-shell structure catalyst comprising an acidic spherical core and multiple spherical outer shells, and its preparation method. The core of the multi-shell structure catalyst of this invention is hollow, and there are pores on its shell walls and on both outer shell layers, with the pores interconnected, such as... Figure 1As shown, this invention solves the problem of high mass transfer resistance in catalytic reactions. The multi-layered shell structure catalyst of this invention is used to catalyze the one-step preparation of RJ-4 or JP-10 precursors from biomass feedstocks. The precursors are oxygen-free, thus solving the problem of multiple steps in the synthesis of RJ-4 or JP-10 in existing technologies.

[0010] The technical solution of the present invention is as follows:

[0011] The first aspect of this invention discloses a multi-layered core-shell structure catalyst, comprising: an acidic spherical core and multiple spherical outer shells. The core and shell layers and the multiple outer shell layers can be regular spherical shells, or irregular spherical shells, such as ellipsoidal shells, flattened spherical shells, or other irregular spherical shells.

[0012] Preferably, the shell wall of the core has pores with a pore size of 0.5nm-30nm, the average diameter of the hollow cavity inside the shell wall of the core is 5.0-200nm, and the shell wall thickness of the core is 5-100nm; the acidic spherical shell-like core is one of acidic metal oxide, molecular sieve, a composite of acidic metal oxide and molecular sieve, or a composite of acidic metal oxide and silicon dioxide.

[0013] Preferably, the acidic metal oxide is NbWOx, WO3, Al2O3, Nb2O5, SiO2-Al2O3, SiO2-Nb2O5, MOF-808-2.5SO4, HfTPA, SnTPA, ZrTPA, or SO4. 2- / ZrO2, MMT-K10, or HPW, or one or more of them; the molecular sieve is Al-MCM-41, Al-SBA-15, Al-SBA-16, Ti-MCM-41, HY, Hβ, HZSM-5, MCM-41, ITQ, KIT-6, or Mordenite, or one or more of them.

[0014] Preferably, the outer shell has two layers, and both outer shell walls have pores with a pore diameter of 0.5nm-100nm; the inner shell layer is a metal oxide composite layer with a thickness of 5-100nm; and the outer shell layer is a solid alkali layer with a thickness of 10-200nm.

[0015] Preferably, the metal oxide composite is ZnMoO X ZrMoO x SiMoO x FeMoO x ZnCoO X ZrCoO x SiCoO x FeCoO x CeMoO x CeCoO XSiMoO x CuCoO X CuMoO X ZnCuMoO X CuFeMoO x ZnFeCoO x One or more of the following; the solid base is CaO and / or MgO, or a complex of CaO and / or MgO with silicon dioxide.

[0016] The second aspect of this invention discloses a method for preparing the multilayer core-shell structured catalyst, comprising the following steps:

[0017] (1) Dissolve a certain amount of the first surfactant in water or a mixture of water and the first alcohol, add carbon spheres, add the core precursor and continue mixing for a period of time; adjust the pH to 10-11 and maintain it, then perform hydrothermal crystallization; after filtration, washing with water and drying, obtain solid powder S1; or,

[0018] Carbon spheres and a second surfactant are added to a second alcohol and stirred until homogeneous. Then, the core precursor is added and stirred until homogeneous. Water is then added and stirred until homogeneous to obtain a sol. The obtained sol is gelled at a certain temperature for a period of time and then heated and dried for a period of time to obtain solid powder S1.

[0019] (2) Add the solid powder S1 obtained in step (1) and the third surfactant to the third alcohol and mix evenly. Then add the inner shell precursor and mix evenly. Add water and continue stirring and adjust the pH value of the solution to generate a sol. Gel the obtained sol at a certain temperature for a period of time. Then dry the gelled sample for a period of time to obtain the catalyst precursor S2.

[0020] (3) Dissolve a certain amount of S2 and the fourth surfactant in an aqueous solution of ammonia and ethanol, then add a solid base precursor and ethanol and mix; after gelation for a period of time, separate the solid, wash and dry it, and then calcine it for a period of time to obtain the multilayer core-shell structure catalyst S3.

[0021] Preferably, the first, second, third, and fourth surfactants are each independently a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (F127), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), oleylamine polyoxyethylene ether (PEG), polyacrylamide (PPG), sorbitan monooleate polyoxyethylene ether (Tween 80), sorbitan monooleate (Span 80), dodecylphenol polyoxyethylene ether (OP-10), isooctylphenyl polyoxyethylene ether (TX-100), or octadecyl alcohol polyoxyethylene ether (Brij). 76), fatty alcohol polyoxyethylene ether (AEO-9), polyethylene glycol octylphenyl ether (TritonX-100), coconut oil fatty acid monoethanolamide (CMEA), C12-14 alkyl glycoside (APG), fatty alcohol polyoxyethylene 3 / 7 / 9 ether (AEO-3 / 7 / 9), nonylphenol polyoxyethylene ether (TX-4.5 / 6).5 / 10 / 15 / 20 / 40), Hydroxy-synthetic alcohol polyoxyethylene ether (GENAPOL UD-080), Hydroxy-synthetic alcohol polyoxyethylene ether (UD-080), Triethanolamine monostearate (emulsifier 4H), Dodecyltrimethylammonium chloride (DTAC), Dodecyltrimethylammonium bromide (DTAB), Hexadecyltrimethylammonium chloride (CTAC), Hexadecyltrimethylammonium bromide (CTAB), Tetrabutylammonium hydroxide (TBAOH), Tetrapropylammonium hydroxide (TPAOH), Dodecyl dimethylbenzylammonium chloride (DDAC), Dodecyl dimethylbenzylammonium bromide (DDAB), Dodecyl trimethylammonium sulfate methyl ester ammonium (BTMS), Alkylpyridine, Alkylmorpholine, Alkyl imidazoline, Alkyl nitrocyclopentane, Lauroamide propylamine oxide (AMP), Cocamidopropyl betaine (DEHYTON) K), dodecylpropyl betaine (BS-12), dodecyl dimethylamine oxide (OA-12), cocamidopropyl dimethyl betaine (CAB-35), cocamidopropyl hydroxysulfonic acid betaine (CHS-35), cocoyl imidazoline (CAMA-30), fatty alcohol (9EO) (AEC-9), sodium dodecyl sulfate (SDS), secondary alkyl sulfate (Teep01), fatty alcohol sulfate (FAS), fatty alcohol sulfate monoethanolamine salt (ASEA), fatty alcohol polyoxyethylene ether sulfate salt (AES), disodium α-sulfated fatty acid (DSFA), dodecyl phosphate (MAP-85), potassium dodecyl phosphate (MAP-K), triethanolamine dodecyl phosphate (MAP-A), tetrabutylbenzene sulfonate (ABS), sodium alkylbenzene sulfonate (LAS), sodium dodecylbenzene sulfonate (SDBS), primary alkyl sulfonate (AS), secondary alkyl sulfonate (SAS), α-olefin sulfonate (AOS), α-sulfonyl fatty acid methyl ester (MES), fatty acid sulfonyl ester (Igepon) A) One or more of the following surfactants: fatty acid sulfonyl amide (Igepon T), sodium diisooctyl succinate sulfonate (AerosolOT), alkyl glycerol ether sulfonate (AGS), sodium dibutylnaphthalene sulfonate (penetrating agent BX), sodium p-methoxy fatty acid amide benzene sulfonate (detergent LS), sodium methylene bisnaphthalene sulfonate (NNO), fatty acid methyl ester sulfonate (MES), sodium fatty acid (SOAP), Lamepon A, sodium carboxymethyl cellulose (SCMC), and sodium acyl sarcosinate (DX107), with a surfactant concentration of 0.1% (w / v) to 10% (w / v).

[0022] Preferably, the first alcohol in step (1) is one or both of ethanol and propanol, and the second alcohol is propanol; the third alcohol in step (2) is propanol; the hydrothermal crystallization temperature in step (1) is 100-140℃, and the time is 1-4 days; the gelation temperature in step (1) or (2) is 45-55℃, and the time is 1-12 days; the drying temperature is 90℃-120℃, and the time is 10-24h; the calcination temperature in step (3) is 350℃-800℃, and the time is more than 2h.

[0023] Preferably, in step (1), the acidic metal oxide precursor in the core precursor is one or more of tungsten chloride, zinc chloride, phosphotungstic acid, niobium chloride, zirconium oxychloride, zirconium chloride, cerium nitrate, niobium oxalate, aluminum chloride, hafnium chloride, tin chloride, tetraethyl silicate, 1,2-bis(triethoxysilyl)ethane, tetrabutyl titanate, sodium silicate, and aluminum silicate; in step (2), the inner shell precursor is a co-deposit of at least two of zinc salt, cerium salt, copper salt, molybdenum salt, tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane, zirconium salt, iron salt, and cobalt salt; and the solid alkali precursor is a co-deposit of one or two of magnesium salt or calcium salt or a complex thereof with tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane.

[0024] A third aspect of this invention discloses the use of the multilayer core-shell structured catalyst for the one-step preparation of oxygen-free precursors of RJ-4 or JP-10 from biomass feedstock. The biomass feedstock is selected from 2,5-hexanedione and / or furfuryl alcohol; the RJ-4 precursor, containing only C-C single bonds and C=C double bonds and free of oxygen, is synthesized from 2,5-hexanedione; the JP-10 precursor, containing only C-C single bonds and C=C double bonds and free of oxygen, is synthesized from furfuryl alcohol.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention is the first to synthesize a multi-layered core-shell catalyst with an acidic spherical core, a metal oxide spherical middle layer, and an alkaline metal oxide spherical outer layer; wherein the shell walls of the core and the two outer shell layers have pores that are interconnected, such as... Figure 1 As shown, the increased permeability of the pores reduces mass transfer resistance and improves mass transfer efficiency in catalytic reactions.

[0027] 2. The multilayer core-shell structure catalyst of this invention can be considered as a three-layer spherical shell structure with a hollow cavity, consisting of an acidic core layer, a metal oxide middle layer, and an alkaline metal oxide outer layer from the inside out. The inner core layer and the two outer shell layers can be regular spherical shells, or non-spherical shells, such as ellipsoidal shells, flattened spherical shells, or other irregular spherical shell shapes. In catalytic reactions, the three layers function from the outside in, respectively, for cyclization, selective hydrogenation, and dehydration condensation. This core-shell structure catalyst of the present invention enables multiple catalyst combinations, allowing for one-step synthesis of RJ-4 or JP-10 precursors with a single catalyst. This solves the problem of currently requiring multiple different catalysts for the synthesis of RJ-4 or JP-10 precursors from biomass, while also avoiding the separation, purification, and transfer of intermediates.

[0028] 3. The multilayer core-shell structure catalyst of the present invention includes, but is not limited to, the following: NbWOx@ZnMoO X @MgO, Al-MCM-41@ZrMoO x @CaO, WO3@SiMoO x @MgO-CaO, Al-SBA-15@FeMoO x @SiO2-MgO、Al-SBA-16@ZnCoO X @SiO2-CaO、Ti-MCM-41@ZrCoO x @SiO2-MgO-CaO、HY@SiCoO x @SiO2-MgO-CaO 、 Hβ@FeCoO x @SiO2-CaO, HZSM-5@CeMoO x @SiO2-MgO、 Al2O3@CeCoO X @MgO-CaO、Nb2O5@SiMoO x @CaO、SiO2-Al2O3@CuCoO X @MgO、CsTPA@CuMoO X @MgO、HfTPA / MCM-41@ZnCuMoO X @CaO、SiO2-Nb2O5@ZrMoO x @MgO-CaO、MOF-808-2.5SO4@SiMoO x @SiO2-MgO、HfTPA@CuFeMoO x @SiO2-CaO、SnTPA@ZnCoO X @SiO2-MgO-CaO、ZrTPA@ZrCoO x @SiO2-MgO-CaO、SO4 2- / ZrO2@SiCoO x @SiO2-CaO、 ITQ@ZnFeCoO x @SiO2-MgO、KIT-6@CeMoO x @MgO-CaO, Mordenite@CeCoO X @CaO, MMT-K10@SiMoO x @MgO、HPW / MCM-41@CuMoO X @MgO. In the description of the multilayer core-shell structure catalyst of this invention, a1 / a2@b@c, the part before the first @ indicates the composition of the core and shell layers, " / " indicates a combination of both, b between the two @ indicates the composition of the inner shell layer, and c after the second @ indicates the composition of the outer shell layer. If each core and shell layer is a bimetallic material or a metal and silicon, the molar ratio is 1:20 to 20:1; if it is a trimetallic material or silicon and two metals, the molar ratio is 1:20:1 to 20:1:20.

[0029] 4. The preparation method of the multilayer core-shell structure catalyst of the present invention uses carbon spheres and a subsequent high-temperature calcination step to prepare a hollow spherical core; simultaneously, the surfactant acting as a template agent is removed through the calcination step, thereby forming interconnected pores on the shell walls of the core and the two outer shells; this reduces mass transfer resistance and improves mass transfer efficiency in catalytic reactions. The multilayer core-shell structure catalyst of the present invention solves the problems of high mass transfer pressure, poor permeability between core and shell layers, and high mass transfer resistance of the solid core in the prior art.

[0030] 5. The multilayer core-shell structure catalyst of this invention is used for one-step catalytic synthesis of RJ-4 precursor from biomass 2,5-hexanedione, or JP-10 precursor from biomass furfuryl alcohol. The RJ-4 or JP-10 precursors contain no oxygen, only C-C single bonds and unsaturated C=C double bonds. The precursors are then hydrogenated to obtain RJ-4 or JP-10. The conditions are mild and easy to achieve, avoiding the harsh conditions of hydrogenation and deoxygenation in existing technologies. The one-step synthesis of RJ-4 or JP-10 precursors avoids the separation, purification, and transfer of intermediates, simplifying the synthesis process of RJ-4 or JP-10. Therefore, the core-shell structure catalyst of this invention is innovative in terms of catalyst, reaction process, and technical means for the catalytic reaction of RJ-4 precursor from biomass 2,5-hexanedione, or JP-10 precursor from biomass furfuryl alcohol.

[0031] 6. The multilayer core-shell structure catalyst of this invention is used for one-step catalytic synthesis of RJ-4 precursor from biomass 2,5-hexanedione, with a feedstock conversion rate of 100% and a fuel precursor yield of not less than 75%; it is also used for one-step catalytic synthesis of JP-10 precursor from biomass furfuryl alcohol, with a feedstock conversion rate of 100% and a fuel precursor yield of not less than 70%. The feedstock is completely converted, and the product yield is high. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the multilayer core-shell structure catalyst of the present invention.

[0033] Figure 2 This is a schematic diagram of the multilayer core-shell structure catalyst of the present invention used to catalyze the one-step preparation of RJ-4 or JP-10 precursors containing only C=C double bonds from biomass feedstock; (a) synthesis of RJ-4 precursor from 2,5-hexanedione; (b) synthesis of JP-10 precursor from furfuryl alcohol. Detailed Implementation

[0034] The technical solution of the present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, the raw materials used in the embodiments are all commercially available products; unless otherwise specified, the processes used are all conventional processes in the art.

[0035] A schematic diagram of the multilayer core-shell structure catalyst of this invention is shown below. Figure 1 As shown. Using the core-shell structured catalyst of this invention, a one-step reaction can be achieved to obtain the RJ-4 precursor from biomass 2,5-hexanedione, or the JP-10 precursor from furfuryl alcohol, as shown. Figure 2 As shown.

[0036] The present invention is as follows Figure 1 The multilayer core-shell structure catalyst shown comprises an acidic spherical core and multiple spherical outer shells. The core and shell layers and the multiple outer shell layers can be regular spherical shells or irregular spherical shells, such as ellipsoidal shells, flattened spherical shells, or other irregular spherical shells.

[0037] The core has pores on its shell wall with a diameter of 0.5 nm to 30 nm, the average diameter of the hollow cavity inside the shell wall of the core is 5.0 to 200 nm, and the shell wall thickness of the core is 5 to 100 nm; the acidic spherical shell-like core is one of acidic metal oxide, molecular sieve, a composite of acidic metal oxide and molecular sieve, or a composite of acidic metal oxide and silicon dioxide.

[0038] Among them, the acidic metal oxides are NbWOx, WO3, Al2O3, Nb2O5, SiO2-Al2O3, SiO2-Nb2O5, MOF-808-2.5SO4, HfTPA, SnTPA, ZrTPA, and SO4. 2- / ZrO2, MMT-K10, or HPW, or one or more of them; the molecular sieve is Al-MCM-41, Al-SBA-15, Al-SBA-16, Ti-MCM-41, HY, Hβ, HZSM-5, MCM-41, ITQ, KIT-6, or Mordenite, or one or more of them.

[0039] The outer shell consists of two layers, both of which have pores with a diameter of 0.5 nm to 100 nm. The inner shell is a metal oxide composite layer with a thickness of 5-100 nm. The outer shell is a solid alkali layer with a thickness of 10-200 nm.

[0040] Among them, the metal oxide composite is ZnMoO X ZrMoO x SiMoO x FeMoO x ZnCoO X ZrCoO x SiCoO x FeCoO x CeMoO x CeCoO X SiMoO x CuCoO X CuMoO X ZnCuMoO X CuFeMoO x ZnFeCoO x One or more of the following; the solid base is CaO and / or MgO, or a complex of CaO and / or MgO with silicon dioxide.

[0041] The multilayer core-shell structured catalyst of the present invention includes, but is not limited to, the following: NbWOx@ZnMoO X @MgO、Al-MCM-41@ZrMoO x @CaO、WO3@SiMoO x @MgO-CaO、Al-SBA-15@FeMoO x @SiO2-MgO、Al-SBA-16@ZnCoO X @SiO2-CaO、Ti-MCM-41@ZrCoO x @SiO2-MgO-CaO、HY@SiCoO x @SiO2-MgO-CaO、Hβ@FeCoO x @SiO2-CaO, HZSM-5@CeMoO x @SiO2-MgO, Al2O3@CeCoO X @MgO-CaO, Nb2O5@SiMoO x @CaO, SiO2-Al2O3@CuCoO X @MgO, CsTPA@CuMoO X@MgO, HfTPA / MCM-41@ZnCuMoO X @CaO、SiO2-Nb2O5@ZrMoO x @MgO-CaO、MOF-808-2.5SO4@SiMoO x @SiO2-MgO、HfTPA@CuFeMoO x @SiO2-CaO、SnTPA@ZnCoO X @SiO2-MgO-CaO、ZrTPA@ZrCoO x @SiO2-MgO-CaO、SO4 2- / ZrO2@SiCoO x @SiO2-CaO、 ITQ@ZnFeCoO x @SiO2-MgO、KIT-6@CeMoO x @MgO-CaO, Mordenite@CeCoO X @CaO, MMT-K10@SiMoO x @MgO、HPW / MCM-41@CuMoO X @MgO. If each core and shell is a bimetal or a metal and silicon, the molar ratio is 1:20 to 20:1; if it is a trimetallic or silicon and two metals, the molar ratio is 1:20:1 to 20:1:20.

[0042] The preparation method of the multilayer core-shell structure catalyst of the present invention includes the following steps:

[0043] (1) Dissolve a certain amount of the first surfactant in water or a mixture of water and the first alcohol, and add carbon spheres. While stirring, add the core precursor sequentially and continue stirring for 2-6 hours. Adjust the pH to 10-11 and maintain for 2 hours. Then place it in a stainless steel reactor lined with polytetrafluoroethylene (PTFE) and hydrothermally crystallize at 100-140℃ for 1-4 days. After crystallization, filter, wash with water, and dry at 90-120℃ for 10-24 hours to obtain the acidic core precursor S1; or...

[0044] Carbon spheres and the second surfactant are added to the second alcohol and stirred until homogeneous. Then, the core precursor is added and stirred until homogeneous. Water is then added and stirred until homogeneous to obtain a sol. The obtained sol is gelled at 45-55℃ for 1-12 days and then heated to 90-120℃ and dried for 10-24 hours to obtain the acidic core precursor S1. Hydrothermal crystallization is required when using an aqueous solvent.

[0045] (2) Add the solid powder S1 obtained in step (1) and the third surfactant to the third alcohol and mix evenly. Then add the inner shell precursor and mix evenly. Add water and continue stirring and adjust the pH value of the solution to form a sol. Gel the obtained sol in a petri dish at 45-55℃ for 1-12 days. Then dry the aged gel sample at 90-120℃ for 10-24h to obtain the catalyst precursor S2 with acidic center and outer shell structure with metal oxide complex precursor.

[0046] (3) Dissolve a certain amount of S2 and the fourth surfactant in an aqueous solution of ammonia in an ethanol solution, then add a solid base precursor and / or a silica precursor, and ethanol, and stir. Gel the mixture in a petri dish at 45-55°C for 1-12 days. Collect the reaction product by centrifugation, wash it three times with water, dry it at 90-120°C for 10-24 hours, and then calcine it in a muffle furnace at 350-800°C for more than 2 hours to obtain the multilayer core-shell structure catalyst S3.

[0047] Among them, the first, second, third, and fourth surfactants are each independently a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), a polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (F127), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), oleylamine polyoxyethylene ether (PEG), polyoxyacrylamide (PPG), sorbitan monooleate polyoxyethylene ether (Tween 80), sorbitan monooleate (Span 80), dodecylphenol polyoxyethylene ether (OP-10), isooctylphenyl polyoxyethylene ether (TX-100), and octadecyl alcohol polyoxyethylene ether (Brij). 76), fatty alcohol polyoxyethylene ether (AEO-9), polyethylene glycol octylphenyl ether (TritonX-100), coconut oil fatty acid monoethanolamide (CMEA), C12-14 alkyl glycoside (APG), fatty alcohol polyoxyethylene 3 / 7 / 9 ether (AEO-3 / 7 / 9), nonylphenol polyoxyethylene ether (TX-4.5 / 6).5 / 10 / 15 / 20 / 40), Hydroxy-synthetic alcohol polyoxyethylene ether (GENAPOL UD-080), Hydroxy-synthetic alcohol polyoxyethylene ether (UD-080), Triethanolamine monostearate (emulsifier 4H), Dodecyltrimethylammonium chloride (DTAC), Dodecyltrimethylammonium bromide (DTAB), Hexadecyltrimethylammonium chloride (CTAC), Hexadecyltrimethylammonium bromide (CTAB), Tetrabutylammonium hydroxide (TBAOH), Tetrapropylammonium hydroxide (TPAOH), Dodecyl dimethylbenzylammonium chloride (DDAC), Dodecyl dimethylbenzylammonium bromide (DDAB), Dodecyl trimethylammonium sulfate methyl ester ammonium (BTMS), Alkylpyridine, Alkylmorpholine, Alkyl imidazoline, Alkyl nitrocyclopentane, Lauroamide propylamine oxide (AMP), Cocamidopropyl betaine (DEHYTON) K), dodecylpropyl betaine (BS-12), dodecyl dimethylamine oxide (OA-12), cocamidopropyl dimethyl betaine (CAB-35), cocamidopropyl hydroxysulfonic acid betaine (CHS-35), cocoyl imidazoline (CAMA-30), fatty alcohol (9EO) (AEC-9), sodium dodecyl sulfate (SDS), secondary alkyl sulfate (Teep01), fatty alcohol sulfate (FAS), fatty alcohol sulfate monoethanolamine salt (ASEA), fatty alcohol polyoxyethylene ether sulfate salt (AES), disodium α-sulfated fatty acid (DSFA), dodecyl phosphate (MAP-85), potassium dodecyl phosphate (MAP-K), triethanolamine dodecyl phosphate (MAP-A), tetrabutylbenzene sulfonate (ABS), sodium alkylbenzene sulfonate (LAS), sodium dodecylbenzene sulfonate (SDBS), primary alkyl sulfonate (AS), secondary alkyl sulfonate (SAS), α-olefin sulfonate (AOS), α-sulfonyl fatty acid methyl ester (MES), fatty acid sulfonyl ester (Igepon) A) One or more of the following surfactants: fatty acid sulfonyl amide (Igepon T), sodium diisooctyl succinate sulfonate (AerosolOT), alkyl glycerol ether sulfonate (AGS), sodium dibutylnaphthalene sulfonate (penetrating agent BX), sodium p-methoxy fatty acid amide benzene sulfonate (detergent LS), sodium methylene bisnaphthalene sulfonate (NNO), fatty acid methyl ester sulfonate (MES), sodium fatty acid (SOAP), Lamepon A, sodium carboxymethyl cellulose (SCMC), and sodium acyl sarcosinate (DX107), with a surfactant concentration of 0.1% (w / v) to 10% (w / v).

[0048] In step (1), the first alcohol is one or both of ethanol and propanol, and the second alcohol is propanol; in step (2), the third alcohol is propanol; the hydrothermal crystallization temperature in step (1) is 100-140℃, and the time is 1-4 days; the gelation temperature in step (1) or (2) is 45-55℃, and the time is 1-12 days; the drying temperature is 90℃-120℃, and the time is 10-24h; the calcination temperature in step (3) is 350℃-800℃, and the time is more than 2h.

[0049] In step (1), the acidic metal oxide precursor in the core precursor is one or more of tungsten chloride, zinc chloride, phosphotungstic acid, niobium chloride, zirconium oxychloride, zirconium chloride, cerium nitrate, niobium oxalate, aluminum chloride, hafnium chloride, tin chloride, tetraethyl silicate, 1,2-bis(triethoxysilyl)ethane, tetrabutyl titanate, sodium silicate, and aluminum silicate; in step (2), the inner shell precursor is a co-deposit of at least two of zinc salt, cerium salt, copper salt, molybdenum salt, tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane, zirconium salt, iron salt, and cobalt salt; and the solid alkali precursor is a co-deposit of one or two of magnesium salt or calcium salt or a complex of it with tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane.

[0050] The multilayer core-shell structure catalyst of this invention can be used to catalyze the one-step preparation of RJ-4 or JP-10 oxygen-free precursors from biomass feedstocks, such as... Figure 2 As shown. The biomass feedstock is selected from 2,5-hexanedione and / or furfuryl alcohol; oxygen-free RJ-4 precursor is synthesized from 2,5-hexanedione; oxygen-free JP-10 precursor is synthesized from furfuryl alcohol.

[0051] Catalyst Preparation Example 1: Preparation of a multilayer core-shell structure catalyst, the steps are as follows:

[0052] (1) 1g of carbon spheres and 1g of surfactant P123 were added to 10g of anhydrous 1-propanol and mixed evenly at 2000rpm. Then, 3mmol of niobium chloride and 3mmol of tungsten chloride were added and the mixture was stirred evenly. Then, 30mmol of water was added and the mixture was stirred evenly to obtain a sol. The obtained sol was gelled in a petri dish at 50℃ for 2 days and then dried in a desiccator at 100℃ for 12h to obtain solid powder S1.

[0053] (2) Add the above solid powder S1 and 1g of P-123 to 10g of anhydrous 1-propanol, stir vigorously, and add 4mmol of (NH4)6Mo7O 24 • 4H2O and 2mmol zinc oxalate were stirred evenly; 30mmol water was added to the solution to adjust the pH to 10-11 and stirred further to obtain a sol; the obtained sol was gelled in a petri dish at 50℃ for 2 days; then the aged gel sample was dried in a desiccator at 100℃ for 12h to obtain catalyst S2;

[0054] (3) S2 and 2.0 g CTAB were dissolved in a mixed solution of 350 mL water, 35 mL ethanol, and 20 mL concentrated ammonia (25 wt%), and heated to 50 °C. Then, 3.0 g magnesium chloride and 7.5 mL ethanol were added to the mixed solution while stirring at 1100 rpm. The mixture was gelled in a petri dish at 50 °C for 2 days. The white reaction product was collected by centrifugation, washed 3 times with water, dried in a drying oven at 100 °C for 12 h, and then calcined in a muffle furnace at 500 °C for 5 h to obtain the multilayer core-shell structure catalyst S3 shown, namely NbWOx@ZnMoO. x @MgO.

[0055] Catalyst Preparation Example 2: Preparation of multilayer core-shell structure catalyst.

[0056] (1) Dissolve 1.8g CTAB in 70mL of water, heat and stir until dissolved to form a transparent solution, and let stand for 10min. While stirring continuously, add 1g carbon balls, 0.2g aluminum nitrate and 5.7g sodium silicate in sequence, mix them evenly, and continue stirring for 2h; adjust the pH of the solution to about 10.50 with 2mol / L sulfuric acid solution, continue stirring for 0.5h to form a uniform gel phase, and adjust the pH to about 10.50 again; then transfer it to a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermally crystallize at 120℃ for 72h; after the hydrothermal crystallization is completed, filter, wash with water and dry at 100℃ for 12h to obtain solid powder S1;

[0057] Steps (2) and (3) are the same as in Example 1. Al-MCM-41@ZnMoO is obtained. x @MgO.

[0058] Other catalysts WO3@SiMoO x @MgO-CaO、Al-SBA-15@FeMoO x @SiO2-MgO、Al-SBA-16@ZnCoO X @SiO2-CaO、Ti-MCM-41@ZrCoO x @SiO2-MgO-CaO、HY@SiCoO x @SiO2-MgO-CaO 、 Hβ@FeCoO x @SiO2-CaO, HZSM-5@CeMoO x @SiO2-MgO、 Al2O3@CeCoO X @MgO-CaO、Nb2O5@SiMoO x @CaO、SiO2-Al2O3@CuCoO X @MgO、CsTPA@CuMoOX @MgO、HfTPA / MCM-41@ZnCuMoO X @CaO、SiO2-Nb2O5@ZrMoO x @MgO-CaO、MOF-808-2.5SO4@SiMoO x @SiO2-MgO、HfTPA@CuFeMoO x @SiO2-CaO、SnTPA@ZnCoO X @SiO2-MgO-CaO、ZrTPA@ZrCoO x @SiO2-MgO-CaO、SO4 2- / ZrO2@SiCoO x @SiO2-CaO、 ITQ@ZnFeCoO x @SiO2-MgO、KIT-6@CeMoO x @MgO-CaO, Mordenite@CeCoO X @CaO, MMT-K10@SiMoO x @MgO、HPW / MCM-41@CuMoO X The preparation methods of MgO and the like are the same or similar to those in Example 1 or Example 2.

[0059] Examples 1-25: Preparation of JP-10 precursors: Multilayer core-shell structure catalysts are used to catalyze the preparation of JP-10 precursors.

[0060] A fixed-bed reactor was used. Before the reaction started, 2.5 g of catalyst S3 was loaded. The multilayer core-shell catalyst was first activated with hydrogen at 400 °C for 2 h. Then, furfuryl alcohol and hydrogen were introduced into the reactor simultaneously as reactants and carrier gases using an HPLC pump. The conditions and results are shown in Table 1.

[0061] Table 1. Precursors for Fuel JP-10 Preparation from Furfuryl Alcohol

[0062]

[0063] As shown in Table 1, biomass furfuryl alcohol can generate JP-10 precursor under the catalysis of the multilayer core-shell structure catalyst of this invention, within a temperature range of 180℃ to 450℃, a hydrogen pressure of 0.1 to 0.5 MPa, a WHSV of 0.10 to 0.45 g / g / h, and an H2 / furfuryl alcohol molar ratio controlled at 30 to 50; the feed conversion rate is 100%, and the yield of fuel precursor is not less than 70%.

[0064] Examples 26-50: Preparation of RJ-4 precursors: Multilayer core-shell structure catalysts for the preparation of RJ-4 precursors.

[0065] The same methods were used for preparing the JP-10 precursor as in Examples 1-25, except that the reactants were replaced with 2,5-hexanedione. The conditions and results are shown in Table 2.

[0066] Table 2. Preparation of fuel RJ-4 precursors from 2,5-hexanedione.

[0067]

[0068] As shown in Table 2, under the catalysis of the multilayer core-shell structure catalyst of the present invention, the biomass 2,5-hexanedione achieves a 100% feedstock conversion rate for generating RJ-4 precursor within a temperature range of 180℃ to 450℃, a hydrogen pressure of 0.1 to 0.5 MPa, a WHSV of 0.10 to 0.45 g / g / h, and an H2 / 2,5-hexanedione molar ratio controlled at 30 to 50, with a fuel precursor yield of not less than 75%.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multilayer core-shell structure catalyst for one-step preparation of RJ-4 or JP-10 oxygen-free precursors from biomass feedstocks, characterized in that, It includes: an acidic spherical core and two spherical outer shells; The shell wall of the core has pores with a diameter of 0.5 nm-30 nm, the average diameter of the hollow cavity inside the shell wall of the core is 5.0-200 nm, and the thickness of the shell wall of the core is 5-100 nm; the acidic spherical shell core is one of acidic metal oxide, molecular sieve, a composite of acidic metal oxide and molecular sieve, or a composite of acidic metal oxide and silicon dioxide. Both outer shells have pores with a diameter of 0.5 nm to 100 nm; the inner shell is a metal oxide composite layer with a thickness of 5 to 100 nm; the outer shell is a solid alkali layer with a thickness of 10 to 200 nm.

2. The multi-layered core-shell structured catalyst according to claim 1, characterized in that, Acidic metal oxides include NbWOx, WO3, Al2O3, Nb2O5, MOF-808-2.5SO4, HfTPA, SnTPA, ZrTPA, and SO4. 2- The molecular sieve is one or more of ZrO2, MMT-K10, or HPW; the molecular sieve is one or more of Al-MCM-41, Al-SBA-15, Al-SBA-16, Ti-MCM-41, HY, Hβ, HZSM-5, ITQ, or Mordenite; the complex of acidic metal oxide and silicon dioxide is SiO2-Al2O3 or SiO2-Nb2O5.

3. The multi-layered core-shell structured catalyst according to claim 1, characterized in that, The metal oxide composite is ZnMoO X ZrMoO x SiMoO x FeMoO x ZnCoO X ZrCoO x SiCoO x FeCoO x CeMoO x CeCoO X CuCoO X CuMoO X ZnCuMoO X CuFeMoO x ZnFeCoO x One or more of the following; the solid base is CaO and / or MgO, or a complex of CaO and / or MgO with silicon dioxide.

4. The method for preparing the multilayer core-shell structured catalyst according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolve a certain amount of the first surfactant in water or a mixture of water and the first alcohol, add carbon spheres, add the core precursor and continue mixing for a period of time; adjust the pH to 10-11 and maintain it, then perform hydrothermal crystallization; after filtration, washing with water and drying, obtain solid powder S1; or, Carbon spheres and a second surfactant are added to a second alcohol and stirred until homogeneous. Then, the core precursor is added and stirred until homogeneous. Water is then added and stirred until homogeneous to obtain a sol. The obtained sol is gelled at a certain temperature for a period of time and then heated and dried for a period of time to obtain solid powder S1. (2) Add the solid powder S1 obtained in step (1) and the third surfactant to the third alcohol and mix evenly. Then add the inner shell precursor and mix evenly. Add water and continue stirring and adjust the pH value of the solution to generate a sol. Gel the resulting sol at a certain temperature for a period of time. The gelled sample was then dried for a period of time to obtain catalyst precursor S2; (3) A certain amount of catalyst precursor S2 and fourth surfactant are dissolved in an aqueous solution of ammonia and ethanol, and then a solid base precursor and ethanol are added and mixed. After gelation for a period of time, the solid is separated, washed and dried, and then calcined for a period of time to obtain the multilayer core-shell structure catalyst S3.

5. The preparation method according to claim 4, characterized in that, The first, second, third, and fourth surfactants are each independently one or more of the following: polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer, polyvinylpyrrolidone, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, dodecyldimethylbenzylammonium chloride, and dodecyldimethylbenzylammonium bromide, with a surfactant concentration of 0.1 w / v % to 10 w / v %.

6. The preparation method according to claim 4, characterized in that, The first alcohol in step (1) is one or both of ethanol and propanol, and the second alcohol is propanol; the third alcohol in step (2) is propanol; the hydrothermal crystallization temperature in step (1) is 100-140℃ and the time is 1-4 days; the gelation temperature in step (1) or (2) is 45-55℃ and the time is 1-12 days; the drying temperature is 90℃-120℃ and the time is 10-24 h; the calcination temperature in step (3) is 350℃-800℃ and the time is more than 2 h.

7. The preparation method according to claim 4, characterized in that, In step (1), the acidic metal oxide precursor in the core precursor is one or more of tungsten chloride, phosphotungstic acid, niobium chloride, zirconium oxychloride, zirconium chloride, niobium oxalate, aluminum chloride, hafnium chloride, tin chloride, and aluminum silicate; the silica precursor in the complex of acidic metal oxide and silica is tetraethyl silicate or 1,2-bis(triethoxysilyl)ethane; in step (2), the inner shell precursor is a co-deposit of at least two of zinc salt, cerium salt, copper salt, molybdenum salt, tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane, zirconium salt, iron salt, and cobalt salt; the solid alkali precursor is one or two of magnesium salt or calcium salt co-deposit or a complex of it with tetraethyl silicate or / and 1,2-bis(triethoxysilyl)ethane.

8. The use of the multilayer core-shell structure catalyst according to any one of claims 1-3 for the one-step preparation of RJ-4 or JP-10 oxygen-free precursors from biomass feedstock.

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