Preparation method of bio-based C17 n-alkanes

Abstract

The invention provides a preparation method of bio-based C17 n-alkanes, which comprises the following steps: carrying out hydrodecarbonylation and decarboxylation reaction on animal and vegetable oil under the action of a hydrodecarbonylation and decarboxylation catalyst to obtain the bio-based C17 n-alkanes, the preparation method of the hydrogenation decarbonylation and decarboxylation catalyst comprises the following steps: 1, mixing magnesium aluminate spinel, TiO2 and a beta molecular sieve, grinding, mixing with a binder, molding, and roasting to obtain a catalyst carrier; and step 2, loading an active component on the catalyst carrier to obtain the hydrodecarbonylation and decarboxylation catalyst, wherein the mass ratio of the magnesium aluminate spinel to the TiO2 to the beta molecular sieve is 100: (0.05-0.5): (1.0-5.0). The TiO2, the beta molecular sieve and the magnesium aluminate spinel are mixed and modified, and when the prepared catalyst is used for preparing bio-based C17 n-alkanes from animal and vegetable oil, the conversion rate is high, and the n-alkanes selectivity is high.

Description

Technical Field

[0001] This invention belongs to the field of chemical reagent production, specifically relating to a method for preparing bio-based C17 n-alkanes. Background Technology

[0002] C15-C18 n-alkanes are mainly used in phase change materials, as well as in pharmaceutical cold chain logistics, phase change energy storage buildings, phase change microcapsules for textiles, and temperature control for electronic components. As solvents, they can also be used for the separation and analysis of lower hydrocarbons, as dewaxing solvents, in machining oils, as base oils for special rust-preventive oils, as base oils for metalworking, as metal cleaning agents, and as reference materials and stationary phases for gas chromatography. They can also be used for gas storage functions such as hydrogen and nitrogen storage.

[0003] Heptadecane has wide applications in functional temperature-regulating textiles, building energy conservation, and cold chain transportation. As a phase change material, heptadecane has a phase change temperature of 22℃, a purity ranging from 99.7% to 99.9%, and an enthalpy of 218 joules / gram. Besides its use as a phase change material, heptadecane can also be fermented to produce heptadecanedioic acid, which can be used to artificially synthesize the precious fragrance civet. Civet is an indispensable raw material in high-grade fragrances and scented products in the fragrance industry, possessing a valuable and delicate animalic aroma and aroma-fixing and preserving properties. Therefore, civet has always been regarded as an indispensable treasure in cosmetic fragrance blending by world-renowned perfumers. Heptadecane is also an environmentally friendly, renewable, pure plant-extracted, natural, and pollution-free non-polar organic solvent, particularly suitable for skin-adhesive applications and ointments. It is an excellent substitute for mineral oil, possessing gloss, lubrication, and skin-moisturizing properties without a greasy feel. Cosmetic applications include: face creams and lotions, makeup, hair care products (shampoo, conditioner, styling gel), deodorants, sunscreens and lotions, makeup removers, shower gels, and hand soaps / soaps.

[0004] The main feedstocks for industrialized production of n-alkanes are petroleum wax and Fischer-Tropsch synthetic oil wax. When producing n-alkanes from petroleum wax and Fischer-Tropsch synthetic oil wax, the process involves complex components such as alkenes, isoalkanes, cycloalkanes, aromatics, and compounds containing oxygen, sulfur, and nitrogen. This requires purification through deep hydrogenation, distillation, and separation of n- and isoalkanes, resulting in a complex production process with demanding conditions.

[0005] Besides using petroleum wax and Fischer-Tropsch synthetic oil wax as raw materials to produce monomeric n-alkanes, there is also the production of monomeric n-alkanes by hydrogenating and deoxygenating animal and vegetable oil esters. However, these methods often suffer from problems such as low conversion rates of animal and vegetable oils into monomeric alkanes, low selectivity for decarbonylation and decarboxylation, and the presence of C16 and C18 byproducts in the products.

[0006] CN200910100260 discloses a method for preparing alkanes from higher fatty acids, using methyl esters of fatty acids with 8-22 carbon atoms as raw materials, and performing hydrodeoxygenation to produce alkanes. However, in the resulting products, most of the carbon atoms in the fatty acids are removed. In addition to decarbonylation and decarboxylation reactions, other side reactions occur. For example, when using methyl stearate (methyl octadecanoate) as raw material, even with a maximum conversion rate of 98%, the total yield of heptadecane and octadecane is only 75%. When using ethyl stearate (ethyl octadecanoate) as raw material, even with a maximum conversion rate of 99%, the total yield of heptadecane and octadecane is only 82%.

[0007] CN201210322774 discloses a method for preparing alkanes by hydrodeoxygenation of non-edible animal and vegetable oils. The method uses a molybdenum-nickel catalyst containing 3-5 wt% cerium oxide and silicon oxide. The main components of the product are mixed alkanes of C15-C18, with an alkane yield of about 82% and a mixed alkanes yield of about 80%. In the prepared mixed aromatics, decarbonylation and decarboxylation reactions occur, generating C15 and C17 alkanes, but the selectivity is not high.

[0008] CN202110518934 discloses a method for preparing high-purity C16 and C18 n-monoalkanes. This method utilizes diluted vegetable oil through a two-bed hydrodeoxygenation reaction combined with distillation separation to produce high-purity C16 and C18 n-monoalkanes. The upper bed is loaded with a molybdenum-nickel catalyst, and the lower bed with a platinum catalyst. The two-bed catalyst solves the problems of high heat release and uneven bed temperature during the hydrodeoxygenation reaction of vegetable oil. The prepared target product has high purity, which can significantly improve the utilization value of vegetable oil. The hydrodeoxygenation products contain 84% n-hexadecane and n-octadecane, while the selectivity for n-pentadecane and n-heptadecane is not high.

[0009] In the production of n-heptadecane, the fossil-based production method depends on the content of n-heptadecane in the raw material. It also requires hydrogenation to remove sulfur, nitrogen, and oxygen impurities from the oil and the presence of aromatics. The bio-based production method produces a large amount of n-octadecane due to the low selectivity of n-heptadecane. In addition, the natural forms of animal and vegetable oils are mostly even-numbered fatty acids or fatty acid esters such as C16 and C18, while odd-numbered fatty acids or fatty acid esters such as C17 are in a co-occurring state and have a low content.

[0010] CN201910190778 discloses a method for decarboxylating unsaturated fatty acids. This method uses a Ru-supported catalyst and, under non-hydrogen-dependent conditions, utilizes an aqueous reforming process with a hydrogen donor to produce hydrogen in situ. A hydrothermal process is employed to achieve the decarboxylation reaction of the unsaturated fatty acids. The unsaturated fatty acids used are selected from one or more of the following: tetradecenoic acid, hexadecenoic acid, oleic acid, eicosenoic acid, erucic acid, linoleic acid, and linolenic acid, all containing double bonds in their carbon chains. The hydrogen donor is selected from one or more of the following: formic acid, methanol, ethanol, isopropanol, glycerol, glucose, amides, urea, sodium borohydride, potassium borohydride, ammonium borohydride, and lithium borohydride. Using linolenic acid as a raw material, methanol as a hydrogen donor, 5wt% Ru / Al₂O₃ catalyst, and water, Ne is introduced into the reactor, maintaining an initial pressure of 1 MPa and a stirring rate of 500 rpm. The reaction is heated to 300℃ and carried out for 9 hours. After the reaction, the resulting liquid product is separated by settling to obtain an organic phase of oil and an inorganic phase of water. The oleic acid conversion rate was 100%, and the yield of long-chain alkanes (the ratio of the amount of long-chain alkanes to the amount of reactants) was 91.1%, including C7 (3.41%), C8 (4.54%), C9 (6.05%), C10 (8.07%), C11 (10.76%), C12 (10.82%), C13 (10.13%), C14 (9.40%), C15 (8.64%), C16 (8.07%), C17 (19.45%), and C18 (0.65%). The C17 content in the product was extremely low.

[0011] CN201510664785 and CN201510665867 disclose a method for preparing long-chain alkanes by in-situ hydrogenation decarboxylation of unsaturated fatty acids or fatty acid methyl esters. Unsaturated fatty acids or fatty acid methyl esters, a non-precious metal catalyst, a hydrogen donor, and water are added to a high-temperature, high-pressure reactor. The unsaturated fatty acids or fatty acid methyl esters are saturated or unsaturated fatty acids or fatty acid methyl esters containing 14–24 carbon atoms. The reactor is heated to 300–390°C for a decarboxylation reaction for 1–6 hours. The decarboxylation product is cooled and filtered to obtain a liquid product. The conversion rate did not reach 100%, and the highest molar yield of long-chain alkanes was 86%.

[0012] CN201610124669 discloses a method for preparing long-chain alkanes by hydrolysis and in-situ hydrogenation and decarboxylation of microalgae oil. After mixing microalgae oil and water, a hydrolysis reaction is carried out by heating, and C10-C22 fatty acids are obtained after processing. The C10-C22 fatty acids, a non-precious metal catalyst, a hydrogen donor, and water are added to a high-temperature and high-pressure reactor and heated to 300-390℃ for decarboxylation reaction for 1-6 hours. The conversion rate did not reach 100%, and the highest yield of long-chain alkanes was 75.6%.

[0013] Current research on the preparation of n-heptadecanes via hydrodeoxygenation mainly focuses on the decarboxylation and decarbonylation of oxygen in the feedstock in the form of CO2 and CO, with the aim of reducing hydrogen consumption. The reactions are mostly batch reactions, and the deoxygenation conversion rate is not high. Therefore, further research is needed in this field on the preparation of C17 n-alkanes. Summary of the Invention

[0014] The main objective of this invention is to provide a method for preparing bio-based C17 n-alkanes, in order to overcome the problems of low conversion rate and selectivity in the conversion of animal and vegetable oils into n-heptadecane in the prior art.

[0015] To achieve the above objectives, the present invention provides a method for preparing bio-based C17 n-alkanes, comprising the following steps:

[0016] Animal and vegetable oils undergo hydrodecarbonylation and decarboxylation reactions under the action of a hydrodecarbonylation and decarboxylation catalyst to obtain bio-based C17 n-alkanes;

[0017] The preparation method of the hydrogenation decarbonylation and decarboxylation catalyst includes:

[0018] Step 1: Mix magnesium aluminum spinel, TiO2 and β molecular sieve, grind them, then mix them with a binder, shape them, and calcine them to obtain a hydrogenation decarbonylation and decarboxylation catalyst support;

[0019] Step 2: The active component is loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support to obtain the hydrogenation decarbonylation and decarboxylation catalyst;

[0020] The mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.05~0.5:1.0~5.0.

[0021] The method for preparing bio-based C17 n-alkanes according to the present invention includes the following steps in the preparation method of magnesium aluminum spinel:

[0022] Magnesium salt, aluminum salt and template agent are mixed to form a solution, and a precipitant is used to carry out a precipitation reaction to obtain a precipitate. The precipitate is then dried and calcined to obtain magnesium aluminum spinel.

[0023] The method for preparing bio-based C17 n-alkanes according to the present invention involves mixing magnesium salts, aluminum salts and acid solutions to obtain solution A, mixing a template agent and water to obtain solution B, then mixing solution A and solution B, adding a precipitant to carry out a precipitation reaction, and obtaining a precipitate.

[0024] The method for preparing bio-based C17 n-alkanes according to the present invention includes, in step 1, the addition of at least one of guar gum powder, a binder and a dispersant for mixing, wherein the binder is boehmite.

[0025] The method for preparing bio-based C17 n-alkanes according to the present invention comprises the following: the mass ratio of the mixture of magnesium aluminum spinel, TiO2, and β molecular sieve to the binder and guar gum powder is 60:30-50:1-5; the adhesive solvent is an aqueous nitric acid solution, and the dispersant is an aqueous citric acid solution; the calcination temperature in step 1 is 450-550℃, and the calcination time is 4-6 h.

[0026] The method for preparing bio-based C17 n-alkanes according to the present invention, wherein the active components are loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support by impregnation, and the active components are molybdenum and nickel.

[0027] The method for preparing bio-based C17 n-alkanes according to the present invention, wherein the molar ratio of molybdenum to nickel is 0.15~0.25:1, the calcination temperature in step 2 is 500~600℃, and the calcination time is 4~8h.

[0028] The method for preparing bio-based C17 n-alkanes according to the present invention, wherein, based on a total mass of 100 parts of the hydrogenation decarbonylation and decarboxylation catalyst support, and the active component being a metal oxide, the mass of the active component in the hydrogenation decarbonylation and decarboxylation catalyst is 20-30 parts; the mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.1-0.2:1.5-2.5.

[0029] The method for preparing bio-based C17 n-alkanes according to the present invention, wherein the active components in the hydrogenation decarbonylation and decarboxylation catalyst are molybdenum and nickel, and the molybdenum:nickel molar ratio is 0.10~0.3:1;

[0030] Before the animal and vegetable oils undergo hydrogenation decarbonylation and decarboxylation reactions, they are first subjected to a hydrogenation pre-purification reaction. The preparation method of the hydrogenation pre-purification catalyst includes:

[0031] Step 1': Mix magnesium aluminum spinel, TiO2 and β molecular sieve, grind them, then mix them with a binder, shape them, and calcine them to obtain a hydrogenation decarbonylation and decarboxylation catalyst support;

[0032] Step 2': The active component is loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support to obtain the hydrogenation decarbonylation and decarboxylation catalyst;

[0033] The mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.05~0.5:1.0~5.0; the active components in the hydrogenation pre-purification catalyst are molybdenum and nickel, and the molybdenum:nickel molar ratio is 1~4:1.

[0034] The method for preparing bio-based C17 n-alkanes according to the present invention includes the following: the animal or vegetable oil is at least one selected from castor oil, cottonseed oil, tung oil, and palm oil; the temperature of the hydrogenation decarbonylation and decarboxylation reaction is 300-400℃, the pressure is 1.5-3MPa, and the hydrogen-to-oil volume ratio is 150-800:1; the temperature of the hydrogenation pre-purification reaction is 80-200℃, the pressure is 1.5-3MPa, and the hydrogen-to-oil volume ratio is 150-800:1.

[0035] The method for preparing bio-based C17 n-alkanes according to the present invention comprises, based on 100 parts of the total mass of the hydrogenation decarbonylation and decarboxylation catalyst support, 20-30 parts of the mass of molybdenum and nickel (calculated as MoO3 and NiO) in the hydrogenation decarbonylation and decarboxylation catalyst support; and based on 100 parts of the mass of the hydrogenation pre-purification catalyst support, 10-15 parts of the mass of molybdenum and nickel (calculated as MoO3 and NiO) in the hydrogenation pre-purification catalyst support.

[0036] The beneficial effects of this invention are:

[0037] The present invention modifies TiO2, β molecular sieve and magnesium aluminum spinel by mixing them. The resulting catalyst has a high conversion rate and high selectivity for n-alkanes when used to prepare bio-based C17 n-alkanes from animal and vegetable oils. Detailed Implementation

[0038] The technical solution of the present invention will be described in detail below. The following embodiments are implemented under the premise of the technical solution of the present invention and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following embodiments. Structures or experimental methods that do not specify specific conditions in the following embodiments are generally performed under conventional conditions.

[0039] This invention provides a method for preparing bio-based C17 n-alkanes, comprising the following steps:

[0040] Animal and vegetable oils undergo hydrodecarbonylation and decarboxylation reactions under the action of a hydrodecarbonylation and decarboxylation catalyst to obtain bio-based C17 n-alkanes;

[0041] The preparation method of the hydrogenation decarbonylation and decarboxylation catalyst includes:

[0042] Step 1: Mix magnesium aluminum spinel, TiO2, and β molecular sieve, grind them, then mix them with boehmite and guar gum powder, shape them, and calcine them to obtain a hydrogenation decarbonylation and decarboxylation catalyst support.

[0043] Step 2: The active component is loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support to obtain the hydrogenation decarbonylation and decarboxylation catalyst;

[0044] The mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.05~0.5:1.0~5.0.

[0045] The present invention modifies TiO2, β molecular sieve and magnesium aluminum spinel by mixing them. The resulting catalyst has a high conversion rate and high selectivity for n-alkanes when used to prepare bio-based C17 n-alkanes from animal and vegetable oils.

[0046] In detail, magnesium aluminum spinel can enhance the hydrodeoxygenation performance of catalysts and has very high water resistance, making it the main component of hydrogenation catalysts for animal and vegetable oils.

[0047] TiO2 exhibits excellent hydrothermal stability. Furthermore, TiO2 interacts strongly with metal active sites, which improves the dispersibility of active components and enhances the anti-sintering properties of supported molybdenum-nickel alloy particles. TiO2 can also enhance the catalyst's resistance to CO2 and CO toxicity and increase the amount of medium-strong acids. In synergy with magnesium aluminum spinel, it improves the selectivity of decarbonylation and decarboxylation during the reaction process, thereby increasing catalyst lifetime and activity stability.

[0048] β-zeolite possesses strong acidity and a unique pore structure, featuring a distinctive three-dimensional twelve-membered ring pore structure. This structure facilitates the effective diffusion and adsorption of molecules within the pores, allowing magnesium aluminum spinel and β-zeolite to complement each other in terms of acidity and pore structure, resulting in a synergistic effect. This enhances the catalyst's hydrogenation performance and improves the selectivity of decarbonylation and decarboxylation during the reaction process.

[0049] In one embodiment, the magnesium aluminum spinel of the present invention is prepared by hydrothermal synthesis, and the preparation method includes, for example, the following steps:

[0050] Magnesium salt, aluminum salt and template agent are mixed to form a solution, and a precipitant is used to carry out a precipitation reaction to obtain a precipitate. The precipitate is then dried and calcined to obtain magnesium aluminum spinel.

[0051] In another embodiment, magnesium salts and aluminum salts are mixed with an acid solution to obtain solution A, and a template agent is mixed with water to obtain solution B. Then, solutions A and B are mixed, and a precipitant is added to carry out a precipitation reaction to obtain a precipitate.

[0052] In this mixture, the acid solution is, for example, a citric acid solution. The magnesium salt and aluminum salt are added sequentially to the citric acid solution to obtain solution A. The magnesium salt is, for example, magnesium nitrate, the aluminum salt is, for example, aluminum nitrate, and the template agent is, for example, hexadecyltrimethylammonium bromide. In one embodiment, the molar ratio of the magnesium salt, aluminum salt, template agent, acid, and water in the mixture is 1:1-3:4-7:0.01-0.03:60-80, for example, 1:2:6:0.01:70.

[0053] In one embodiment, a solution formed by mixing magnesium salt, aluminum salt, and a template agent is heated and stirred until homogeneous. Then, a precipitant is added to induce a precipitation reaction. The precipitant, for example, is ammonia. The addition of the precipitant adjusts the pH of the mixed solution to the range of 7.8–9.1. The mixture is then placed in a constant-temperature water bath and stirred continuously until a precipitate is obtained. The precipitate is then statically aged in an oven at room temperature for 2–4 hours, dried at 100–120°C, ground to 300–400 mesh, and calcined at 650–750°C with a heating rate of 2–3°C / min for 6–10 hours to obtain magnesium aluminum spinel powder.

[0054] This invention does not impose any particular limitation on the source of TiO2 and β-zeolite, and they can be commercially available products. In one embodiment, the mass ratio of magnesium aluminum spinel, TiO2, and β-zeolite in the hydrodecarbonylation and decarboxylation catalyst is 100:0.05~0.3:1.0~3.5, preferably 100:0.1~0.2:1.5~2.5.

[0055] This invention does not impose any particular limitation on the grinding method of magnesium aluminum spinel, TiO2, and β molecular sieve; any conventional method in the art is acceptable. In one embodiment, at least one of guar gum powder, a peptizing agent, and a dispersant is added during the mixing of the magnesium aluminum spinel, TiO2, and β molecular sieve with the binder in step 1. The binder is, for example, boehmite; the peptizing agent is, for example, an aqueous solution of nitric acid; and the dispersant is, for example, an aqueous solution of citric acid.

[0056] Guaranteed sesame powder primarily functions as a binder, lubricant, extrusion aid, and pore-forming agent. It enhances adhesion, making the molded product easier to shape; it lubricates during extrusion, reducing friction and improving production efficiency; and during calcination, it undergoes pyrolysis, forming pores that help increase the catalyst's specific surface area and activity.

[0057] The main function of nitric acid is to regulate adhesion and strength. Nitric acid can act as a binder, influencing the catalyst's molding effect by adjusting its adhesion and strength. It can also react with other components in the catalyst to form stable compounds, thereby enhancing the catalyst's mechanical strength and stability.

[0058] Citric acid can improve the dispersion of active components on the support surface through chelation and isolation effects. Specifically, citric acid can form complexes with metal ions, thereby preventing the aggregation of metal ions on the support surface and increasing their dispersibility. This improved dispersibility helps the catalyst exhibit higher activity and selectivity in the reaction.

[0059] In one embodiment, the mass ratio of the mixture of magnesium aluminum spinel, TiO2, and β-molecular sieve in step 1 to pseudoboehmite and guar gum powder is 60:30-50:1-5. Nitric acid aqueous solution and / or citric acid aqueous solution are added to the mixture of magnesium aluminum spinel, TiO2, β-molecular sieve, pseudoboehmite, and guar gum powder. The concentration of the nitric acid aqueous solution is, for example, 3-5 wt%, and the concentration of the citric acid aqueous solution is, for example, 2-6 wt%. The mixture is stirred into fine granules, kneaded 2-3 times using a twin-screw extruder, and then extruded into strips using a perforated plate with a diameter of φ1.5-2.0 mm. The wet strips are allowed to air dry naturally at room temperature and then calcined in a muffle furnace to obtain a hydrodecarbonylation and decarboxylation catalyst support. The calcination temperature is, for example, 450-550°C, and the calcination time is, for example, 4-6 h.

[0060] This invention does not particularly limit the manner in which the active component is supported on the hydrodecarbonylation and decarboxylation catalyst support. In one embodiment, the support method is impregnation, such as equal-volume impregnation or excess impregnation. In this invention, based on 100 parts by total mass of the hydrodecarbonylation and decarboxylation catalyst support, the active component, calculated as a metal oxide, comprises 15-30 parts by mass, preferably 20-30 parts. The active component in this invention can be molybdenum and nickel, with a molar ratio of molybdenum to nickel, for example, 0.10-0.3:1, preferably 0.15-0.25:1.

[0061] In one embodiment, an impregnation solution is formed from the active component precursor and used to impregnate the catalyst support. After impregnation, the solution is cured at room temperature for 2 hours, with stirring every 20 minutes to ensure uniform impregnation. After curing, the solution is poured into a crucible and placed in a drying oven at 110-120°C for 4-8 hours, followed by calcination at 500-600°C for 4-8 hours to obtain the hydrodecarbonylation and decarboxylation catalyst. The mass ratio of the impregnation solution to the support is, for example, 0.6-0.8:1, specifically, for example, 0.7:1.

[0062] In one embodiment, the precursor of nickel can be nickel nitrate, and the precursor of molybdenum can be ammonium molybdate heptahydrate, but the present invention is not limited thereto.

[0063] The hydrogenation decarbonylation and decarboxylation catalyst of this invention can be used for hydrogenation decarbonylation and decarboxylation reactions of animal and vegetable oils to prepare C17 n-alkanes. It has high water resistance, high resistance to CO2 and CO toxicity, and high to medium strong acid content. It can control the decarbonylation and decarboxylation reactions in the reaction process, improve the selectivity and yield of the target monomer C17 n-alkanes, and reduce the pressure of subsequent separation.

[0064] Specifically, nickel is beneficial for hydrodecarboxylation and decarbonylation reactions, while molybdenum is beneficial for hydrodehydration reactions. At a low molybdenum-nickel ratio, the total acidity of the catalyst can be increased with the increase of the molybdenum-nickel ratio. The increase in acidity is beneficial for the breaking of C-C bonds during the hydrodeoxygenation of vegetable oil, and the catalytic performance of the catalyst shifts towards decarbonylation and decarboxylation. Adding an appropriate amount of nickel can promote the reduction of MoO3, which is more beneficial for the reduction of the catalyst.

[0065] In this invention, the animal and vegetable oils are non-edible vegetable oils and / or waste animal and vegetable oils, which can be purchased directly or refined from oils as raw materials. The purpose of refining is to remove impurities such as phosphorus and chlorine metals from the animal and vegetable oils, including castor oil, cottonseed oil, jacaranda oil, palm oil, and lipids or any combination thereof. In one embodiment, the animal and vegetable oils are mixed with a solvent and placed in a fixed-bed reactor. Under the action of the above-mentioned hydrodecarbonylation and decarboxylation catalyst, the hydrodecarboxylation and decarbonylation reaction temperature is 300~400℃, preferably 340~380℃, the reaction pressure is 1.5~3MPa, preferably 1.5~2.5MPa, and the reaction mass hourly space velocity is 1.5~3.0h. -1 Preferably 1.5~2.5h -1 The hydrogen-to-oil volume ratio is 150-800:1, preferably 200-600:1, and the solvent volume accounts for 50-90% of the reaction mixture, preferably 70-90%, to carry out a hydrogenation-decarbonylation-decarboxylation reaction to obtain a C17 n-alkanes. The solvent can be cyclohexane, n-heptadecane, etc.

[0066] In one embodiment, before the animal and vegetable oils undergo hydrodecarbonylation and decarboxylation reactions, a pre-hydrogenation purification reaction is first performed to saturate the olefins. The preparation method of the pre-hydrogenation purification catalyst is similar to that of the hydrodecarbonylation and decarboxylation catalyst, the difference being the molar ratio of the active components molybdenum and nickel. In the hydrodecarbonylation and decarboxylation catalyst, the molar ratio of molybdenum to nickel is 0.10 to 0.3:1; in the pre-hydrogenation purification catalyst, the molar ratio of molybdenum to nickel is 1 to 4:1, preferably 2 to 3:1.

[0067] In another embodiment, the preparation method of the hydrotreating pre-purification catalyst differs from that of the hydrodecarbonylation and decarboxylation catalyst in that the content of the active components is different. Based on 100 parts by weight of the total mass of the hydrodecarbonylation and decarboxylation catalyst support, the mass of molybdenum and nickel (calculated as MoO3 and NiO) in the hydrodecarbonylation and decarboxylation catalyst is 20-30 parts; based on 100 parts by weight of the hydrotreating pre-purification catalyst support, the mass of molybdenum and nickel (calculated as MoO3 and NiO) in the hydrotreating pre-purification catalyst is 10-15 parts.

[0068] Apart from that, the preparation method of the hydrogenation pre-purification catalyst is exactly the same as that of the hydrogenation decarbonylation and decarboxylation catalyst.

[0069] In this invention, the temperature of the hydrotreating pre-purification reaction is 80~200℃, preferably 100~170℃, the pressure is 1.5~3MPa, and the hydrogen-to-oil volume ratio is 150~800:1. A solvent is also added to the hydrotreating pre-purification reaction, with a solvent proportion (solvent volume ratio of the reaction mixture) of 50~95%. The volume ratio of the catalysts in the hydrotreating pre-purification section and the hydrodecarboxylation and decarbonylation section is 10~20:100, preferably 12~18:100.

[0070] The present invention does not specifically limit the apparatus for the hydrogenation pre-purification reaction and the hydrogenation decarbonylation and decarboxylation reaction. The catalyst can be packed in the same reaction apparatus or carried out in two reaction apparatuses.

[0071] This invention employs a two-stage reaction. The first-stage catalyst functions as olefin saturation, converting the olefins and dienes in the raw materials into saturated fatty acid esters. This releases heat in advance, reducing the exothermic reaction of the second-stage catalyst. This results in more stable temperature control of the second-stage hydrogenation, decarboxylation, and decarbonylation catalyst, reducing the solvent dilution ratio and minimizing the ineffective load on the equipment. Simultaneously, olefin saturation in the low-temperature zone prevents the raw materials from polymerizing and coking.

[0072] In this invention, the conversion rate of the raw materials can reach 100%, and the selectivity of the target product, C17 n-alkanes, can reach over 97%. The purity of the monomeric n-alkanes is all above 98.5%, the sulfur, nitrogen, phosphorus, and oxygen content are all below 8 μg / g, the total metal content is below 10 μg / g, and aromatic hydrocarbons are not detected.

[0073] The technical solution of the present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the reagents and materials mentioned can be obtained from commercial channels.

[0074] Magnesium nitrate: Magnesium nitrate hexahydrate, Tianjin Fuchen, 98%

[0075] Aluminum nitrate: Tianjin Fuchen, 99%

[0076] Nickel nitrate: Nickel nitrate hexahydrate, Aladdin reagent, AR, 98%

[0077] Ammonium molybdate heptahydrate: Shanghai Yihe Biotechnology, AR, 99.95%

[0078] Citric acid: Jinan Century Tongda, 95%

[0079] Nitric acid: Tianjin Kemio Reagent Co., Ltd., AR, 70%

[0080] Ammonia solution: Tianjin Kemio Reagent Co., Ltd., AR, 25%

[0081] Hexadecyltrimethylammonium bromide: Aladdin reagent, AR, 98%

[0082] Boehmite: Yangzhou Zhongtianli New Material Co., Ltd., industrial agent, 99.9%.

[0083] β-molecular sieve: Tianjin Nanhua Catalyst Co., Ltd.

[0084] TiO2 powder: Hubei Dechao Chemical Co., Ltd.

[0085] Ru / C: Merck (Sigma-Aldrich) Life Sciences, 5wt%

[0086] Linoleic acid: Chengdu Keshi Chemical Co., Ltd., 98%

[0087] Cottonseed oil: Yunnan Shenyu

[0088] Tung oil refined from ancient trees: Yunnan Shenyu

[0089] Ruthenium trichloride trihydrate: RuCl3·3H2O, Shanghai Aoke Industrial Co., Ltd.

[0090] Sodium acetate trihydrate: CH3CO2Na.3H2O, Sinopharm Chemical Reagent Co., Ltd.

[0091] Zirconium oxychloride aqueous solution: ZrOCl2·8H2O, Sinopharm Chemical Reagent Co., Ltd.

[0092] Preparation of magnesium aluminum spinel powder:

[0093] A hydrothermal synthesis method was used. A certain amount of citric acid was weighed and added to deionized water and stirred until completely dissolved. Then, magnesium nitrate and aluminum nitrate were weighed and added sequentially to the citric acid aqueous solution to obtain solution A. A certain amount of hexadecyltrimethylammonium bromide was weighed and dissolved in deionized water to obtain solution B. The molar ratio of magnesium nitrate, aluminum nitrate, hexadecyltrimethylammonium bromide, citric acid, and water was 1:2:6:0.01:70.

[0094] Solution A and solution B are mixed, heated and stirred until homogeneous. The pH of the mixed solution is adjusted by adding ammonia dropwise to a range of 7.8 to 9.1. The mixed solution is placed in a constant temperature water bath and stirred until a precipitate is obtained. The precipitate is statically aged in an oven at room temperature for 2 to 4 hours. After drying at 100 to 120°C, it is ground to 300 to 400 mesh and calcined at 650 to 750°C with a heating rate of 2 to 3°C / min for 6 to 10 hours to obtain magnesium aluminum spinel powder.

[0095] Example 1

[0096] (1) Preparation of the molded carrier

[0097] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.1 parts, and β-molecular sieve powder was 2 parts. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3 wt% nitric acid and 4 wt% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0098] (2) Active ingredient loading

[0099] Hydrogenation pre-purification catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to obtain an impregnation solution. The solution consisted of 100 parts by weight of the support and 10 parts by weight of the active component (MoO3 + NiO), with a molar ratio of molybdenum to nickel of 3:1. The mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 4 hours. Finally, the solution was calcined at 500°C for 6 hours to obtain the hydrogenation pre-purification catalyst.

[0100] Hydrogenation decarboxylation and decarbonylation catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to prepare an impregnation solution. The active component (MoO3 + NiO) was 25 parts per 100 parts by weight of the support, with a molar ratio of molybdenum to nickel of 0.2:1. The mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 8 hours. The catalyst was then calcined at 550°C for 6 hours to obtain the hydrogenation decarboxylation and decarbonylation catalyst.

[0101] (3) Catalyst evaluation

[0102] Using tung oil as raw material, a fixed-bed reactor was used. The catalyst was graded and packed, with a pre-hydrogenation pre-purification catalyst in the front section and a hydrodecarboxylation and decarbonylation catalyst in the back section. The volume ratio of the front to back catalysts was 12:100. The reaction temperature in the front section was 100℃, and the reaction temperature in the back section was 350℃. The reaction pressure was 2 MPa, and the mass hourly space velocity (H₂S₀) was 2 h⁻¹. -1 The hydrogen-to-oil volume ratio was 400:1, and the solvent accounted for 90%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0103] Example 2

[0104] (1) Preparation of the molded carrier

[0105] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.15 parts, and β-molecular sieve powder was 1.5 parts. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3% nitric acid and 4% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0106] (2) Active metal loading

[0107] Hydrogenation pre-purification catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to obtain an impregnation solution. The solution consisted of 100 parts by weight of the support and 15 parts by weight of the active component (MoO3 + NiO). The molar ratio of molybdenum to nickel was 2.5:1, and the mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 4 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 6 hours. Finally, the solution was calcined at 500°C for 8 hours to obtain the hydrogenation pre-purification catalyst.

[0108] Hydrogenation decarboxylation and decarbonylation catalyst: A certain amount of nickel nitrate was dissolved in deionized water, and then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to prepare an impregnation solution. The solution consisted of 100 parts by weight of the support and 20 parts by weight of the active component (MoO3 + NiO). The molar ratio of molybdenum to nickel was 0.15:1, and the mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 6 hours. The catalyst was then calcined at 650°C for 6 hours to obtain the hydrogenation decarboxylation and decarbonylation catalyst.

[0109] (3) Catalyst evaluation

[0110] Using tung oil as raw material, a fixed-bed reactor was used with graded catalyst loading. The front section consisted of a hydrotreating pre-purification catalyst, and the rear section consisted of a hydrodecarboxylation and decarbonylation catalyst. The volume ratio of the front to rear catalysts was 15:100. The front reaction temperature was 130℃, the rear reaction temperature was 340℃, the reaction pressure was 1.5 MPa, and the mass hourly space velocity (HHSV) was 2 h⁻¹. -1The hydrogen-to-oil volume ratio was 250:1, and the solvent accounted for 85%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0111] Example 3

[0112] (1) Preparation of the molded carrier

[0113] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.15 parts, and β-molecular sieve powder was 2 parts. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3% nitric acid and 4% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0114] (2) Active metal loading

[0115] Hydrogenation pre-purification catalyst: A certain amount of nickel nitrate was dissolved in deionized water, and then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to obtain an impregnation solution. The solution consisted of 100 parts by weight of the support and 12 parts by weight of the active component (MoO3 + NiO). The molar ratio of molybdenum to nickel was 2.5:1, and the mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 4 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 4 hours. Finally, the solution was calcined at 500°C for 4 hours to obtain the hydrogenation pre-purification catalyst.

[0116] Hydrogenation decarboxylation and decarbonylation catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to prepare an impregnation solution. The active component (MoO3 + NiO) was 25 parts per 100 parts by weight of the support, with a molar ratio of molybdenum to nickel of 0.2:1. The mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 8 hours. The catalyst was then calcined at 550°C for 6 hours to obtain the hydrogenation decarboxylation and decarbonylation catalyst.

[0117] (3) Catalyst evaluation

[0118] Using tung oil as raw material, a fixed-bed reactor was used. The catalyst was graded and packed, with a pre-hydrogenation pre-purification catalyst in the front section and a hydrodecarboxylation and decarbonylation catalyst in the back section. The volume ratio of the front to back catalysts was 15:100. The reaction temperature in the front section was 150℃, and the reaction temperature in the back section was 360℃. The reaction pressure was 2 MPa, and the mass hourly space velocity (H₂S₀) was 2 h₀. -1 The hydrogen-to-oil volume ratio was 350:1, and the solvent content was 80%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0119] Example 4

[0120] (1) Preparation of the molded carrier

[0121] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.05 parts, and β-molecular sieve powder was 1.0 part. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3% nitric acid and 4% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0122] (2) Active ingredient loading

[0123] Hydrogenation pre-purification catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to obtain an impregnation solution. The solution consisted of 100 parts by weight of the support and 13 parts by weight of the active component (MoO3 + NiO). The molar ratio of molybdenum to nickel was 2:1. The mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 4 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 4 hours. Finally, the solution was calcined at 500°C for 4 hours to obtain the hydrogenation pre-purification catalyst.

[0124] Hydrogenation decarboxylation and decarbonylation catalyst: A certain amount of nickel nitrate was weighed and dissolved in deionized water, then ammonium molybdate heptahydrate was added. The mixture was heated and stirred until completely dissolved to prepare an impregnation solution. The active component, calculated as 20 parts by mass of MoO3 + NiO (100 parts by mass of the support), had a molar ratio of molybdenum to nickel of 0.15:1. The impregnation solution and support were used to impregnate the active component at a mass ratio of 0.7:1. After impregnation, the mixture was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the mixture was poured into a crucible and dried in a drying oven at 120°C for 6 hours. The catalyst was then calcined at 650°C for 6 hours to obtain the hydrogenation decarboxylation and decarbonylation catalyst.

[0125] (3) Catalyst evaluation

[0126] Using tung oil as raw material, a fixed-bed reactor was used with graded catalyst loading. The front section consisted of a hydrotreating pre-purification catalyst, and the rear section consisted of a hydrodecarboxylation and decarbonylation catalyst, with a front-to-rear catalyst volume ratio of 10:100. The front-section reaction temperature was 80℃, the rear-section reaction temperature was 300℃, the reaction pressure was 1.5 MPa, and the mass hourly space velocity (HHSV) was 3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 150:1, and the solvent accounted for 95%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0127] Example 5

[0128] Refer to Example 3 for carrier preparation and active metal loading.

[0129] (1) Catalyst evaluation

[0130] Using tung oil as raw material, a fixed-bed reactor was used with graded catalyst loading. The front section consisted of a hydrotreating pre-purification catalyst, and the rear section consisted of a hydrodecarboxylation and decarbonylation catalyst, with a front-to-rear catalyst volume ratio of 18:100. The front-section reaction temperature was 150℃, the rear-section reaction temperature was 360℃, the reaction pressure was 2 MPa, and the mass hourly space velocity (HHSV) was 2.8 h⁻¹. -1 The hydrogen-to-oil volume ratio was 350:1, and the solvent accounted for 85%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0131] Example 6

[0132] Refer to Example 3 for carrier preparation and active metal loading.

[0133] (1) Catalyst evaluation

[0134] Using tung oil as raw material, a fixed-bed reactor was used with graded catalyst loading. The front section consisted of a hydrotreating pre-purification catalyst, and the rear section consisted of a hydrodecarboxylation and decarbonylation catalyst, with a front-to-rear catalyst volume ratio of 18:100. The front-section reaction temperature was 160℃, the rear-section reaction temperature was 360℃, the reaction pressure was 2MPa, and the mass hourly space velocity (H₂S₀) was 2.5h⁻¹. -1 The hydrogen-to-oil volume ratio was 500:1, and the solvent accounted for 80%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0135] Example 7

[0136] (1) Preparation of the molded carrier

[0137] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.15 parts, and β-molecular sieve powder was 2.5 parts. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3% nitric acid and 4% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0138] Referring to Example 3, active metal loading was performed.

[0139] (2) Catalyst evaluation

[0140] Using refined castor oil as feedstock, a dual-reactor fixed-bed reactor was employed. The first reactor was loaded with a hydrotreating pre-refining catalyst, while the second reactor was loaded with a hydrodecarboxylation and decarbonylation catalyst. The volume ratio of the first to second reactor catalysts was 15:100. The reaction temperature for the first reactor was 140℃, and for the second reactor it was 380℃. The reaction pressure was 2.5 MPa, and the mass hourly space velocity (HHSV) was 3 h⁻¹. -1 The hydrogen-to-oil volume ratio was 600:1, and the solvent accounted for 75%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0141] Example 8

[0142] Refer to Example 3 for carrier preparation and active metal loading.

[0143] (1) Catalyst evaluation

[0144] Using refined cottonseed oil as feedstock, a dual-reactor fixed-bed reactor was employed. The first reactor was loaded with a hydrotreating pre-refining catalyst, while the second reactor was loaded with a hydrodecarboxylation and decarbonylation catalyst. The volume ratio of the first to second reactor catalysts was 15:100. The reaction temperature for the first reactor was 120℃, and for the second reactor it was 350℃. The reaction pressure was 2.5 MPa, and the mass hourly space velocity (HHSV) was 1.6 h⁻¹. -1 The hydrogen-to-oil volume ratio was 400:1, and the solvent accounted for 55%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0145] Example 9

[0146] Refer to Example 3 for carrier preparation and active metal loading.

[0147] (1) Catalyst evaluation

[0148] Using stearic acid as raw material, a dual-reactor fixed-bed reactor was employed. The first reactor was loaded with a hydrogenation pre-purification catalyst, and the second reactor was loaded with a hydrogenation decarboxylation and decarbonylation catalyst. The volume ratio of the first reactor to the second reactor catalyst was 12:100. The reaction temperature of the first reactor was 170℃, and that of the second reactor was 370℃. The reaction pressure was 2.5 MPa, and the mass hourly space velocity (H₂S₀) was 2 h₀. -1 The hydrogen-to-oil volume ratio was 500:1, and the solvent content was 60%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0149] Example 10

[0150] (1) Preparation of the molded carrier

[0151] TiO2 powder, β-molecular sieve, and magnesium aluminum spinel powder were ground evenly. The magnesium aluminum spinel was 100 parts by weight, TiO2 powder was 0.15 parts, and β-molecular sieve powder was 2 parts. The mixed powders, along with boehmite and guar gum powder, were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3% nitric acid and 4% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder, and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain the catalyst support.

[0152] (2) Active metal loading

[0153] A certain amount of nickel nitrate was weighed and dissolved in deionized water. Ammonium molybdate heptahydrate was then added, and the mixture was heated and stirred until completely dissolved to prepare an impregnation solution. The solution consisted of 100 parts by weight of the support and 25 parts by weight of the active component (MoO3 + NiO), with a molar ratio of molybdenum to nickel of 0.2:1. The impregnation solution and support were used to impregnate the active component at a mass ratio of 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 8 hours. Finally, the solution was calcined at 550°C for 6 hours to obtain the hydrogenation decarboxylation and decarbonylation catalyst.

[0154] (3) Catalyst evaluation

[0155] Refined tung oil was mixed with a solvent and subjected to hydrodecarboxylation and decarbonylation in a fixed-bed reactor. The hydrodeoxygenation reaction was carried out at a temperature of 360°C, a pressure of 2 MPa, and a mass hourly space velocity of 2 h⁻¹. -1 The hydrogen-to-oil volume ratio was 350:1, and the solvent content was 80%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenation product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0156] Comparative Example 1

[0157] Under stirring conditions at room temperature, ammonia water (25-28 wt%) was added to an aqueous solution of zirconium oxychloride until the pH reached 10. After stirring for 3 h, the solution was refluxed at 100 °C for 48 h. The precipitate was washed with deionized water until neutral, and then dried in an oven at 100 °C for 24 h. The resulting solid was ground and calcined in a muffle furnace at 600 °C for 5 h.

[0158] At room temperature, ruthenium trichloride trihydrate (3.96 mmol / L) and sodium acetate trihydrate (9.76 mmol / L) were dissolved in alcohol, and then the ZrO2 powder prepared above was added. The Ru loading was 5 wt%. The alcohol solution was added with stirring and heated to 160 °C and maintained for 30 min. After cooling, the solid was separated by centrifugation and washed with deionized water until no chloride ions were present in the centrifuged liquid (detected by silver nitrate). The alcohol was ethylene glycol, and the catalyst was prepared.

[0159] 10 g of linoleic acid, 0.5 g of urea, 1 g of 5 wt% Ru / ZrO2 catalyst, and 100 g of H2O were added to a 250 mL batch high-temperature and high-pressure reactor. The reactor was sealed, and N2 was introduced into the reactor to maintain an initial pressure of 2 MPa. The stirring rate was 500 rpm. The temperature was raised to 330 °C and the reaction was carried out for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, dissolved in dichloromethane, and filtered to obtain a liquid product and a solid catalyst. The liquid product was then separated by settling to obtain an organic phase of oil and an inorganic phase of water. The separated organic phase was diluted to volume with dichloromethane and then analyzed.

[0160] Comparative Example 2

[0161] 5g of linoleic acid, 5g of linolenic acid, 3g of sodium borohydride, 2g of 5wt% Ru / C catalyst, and 120g of H2O were added to a 250mL batch high-temperature and high-pressure reactor. The reactor was sealed, and He was introduced into the reactor to maintain an initial pressure of 3MPa. The stirring speed was 500rpm. The temperature was raised to 350℃ and the reaction was carried out for 1 hour. After the reaction was completed, the reaction product was cooled to room temperature, dissolved in dichloromethane, and filtered to obtain a liquid product and a solid catalyst. The obtained liquid product was then separated by settling to obtain an organic phase of oil and an inorganic phase of water. The separated organic phase was diluted to volume with dichloromethane and then analyzed.

[0162] Comparative Example 3

[0163] (1) Preparation of the molded carrier

[0164] TiO2 powder was ground evenly. TiO2 powder, boehmite, and guar gum powder were mixed in a mass ratio of 60:40:3. An aqueous solution containing 3 wt% nitric acid and 4 wt% citric acid was added, and the mixture was stirred into fine granules. The granules were then kneaded three times using a twin-screw extruder and extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature and then calcined in a muffle furnace at 500℃ for 4 hours to obtain catalyst support A.

[0165] The β-molecular sieve was ground uniformly. β-molecular sieve powder, boehmite, and guar gum powder were added to an aqueous solution containing 3 wt% nitric acid and 4 wt% citric acid at a mass ratio of 60:40:3. The mixture was stirred into fine granules, kneaded three times using a twin-screw extruder, and then extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain catalyst support B.

[0166] Magnesium aluminum spinel powder was ground evenly. Magnesium aluminum spinel powder, boehmite, and guar gum powder were added to an aqueous solution containing 3 wt% nitric acid and 4 wt% citric acid at a mass ratio of 60:40:3. The mixture was stirred into fine granules, kneaded three times using a twin-screw extruder, and then extruded into strips using a φ2.0 perforated plate. The wet strips were allowed to air dry naturally at room temperature, and then calcined in a muffle furnace at 500℃ for 4 hours to obtain catalyst support C.

[0167] (2) Active ingredient loading

[0168] A certain amount of nickel nitrate was weighed and dissolved in deionized water. Ammonium molybdate heptahydrate was then added, and the mixture was heated and stirred until completely dissolved to obtain an impregnation solution. Using supports A, B, and C as catalyst supports, with each support weighing 100 parts, the active component (MoO3 + NiO) weighing 25 parts, and a molar ratio of molybdenum to nickel of 0.2:1, the mass ratio of the impregnation solution to the support was 0.7:1. After impregnation, the solution was cured at room temperature for 2 hours, stirring every 20 minutes to ensure uniform impregnation. After curing, the solution was poured into a crucible and dried in a drying oven at 120°C for 8 hours. Finally, the solution was calcined at 550°C for 6 hours to obtain the corresponding titanium-based catalyst, β-based catalyst, and magnesium-aluminum spinel catalyst.

[0169] (3) Catalyst evaluation

[0170] The prepared titanium-based catalyst, β-based catalyst, and magnesium-aluminum spinel catalyst were mixed at a mass ratio of 0.15:2:100. After thorough mixing, the mixture was loaded into a fixed-bed reactor. Refined tung oil was mixed with a solvent, and the reaction was carried out under the action of the mixed catalyst. The hydrodeoxygenation reaction temperature was 360℃, the reaction pressure was 2MPa, and the reaction mass hourly space velocity was 2h. -1 The hydrogen-to-oil volume ratio was 350:1, and the solvent content was 80%. The hydrodeoxygenation product was separated from water. The properties of the feed oil are shown in Table 1, and the catalyst evaluation results are shown in Table 2. A Fisher 2892 true boiling point apparatus was used to distill the deoxygenated product after oil-water separation to separate the monomeric n-heptadecane. The properties of the monomeric n-heptadecane are shown in Table 3.

[0171] Gas chromatography was used to analyze the mixed alkanes of the product and the monomer n-heptadecane after distillation using a true boiling point apparatus. An HP-1 capillary column (60m × 0.25mm × 1.00µm) manufactured by Agilent Technologies was selected.

[0172]

[0173] Note: Oxygen content was analyzed using an Elementar vario MICRO0.20CUBE elemental analyzer (Germany). a: Cyclohexane diluted 100-fold; b: Cyclohexane diluted 100-fold; detection limit 100 mg / kg. Carbon number distribution was analyzed using gas chromatography.

[0174]

[0175] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing bio-based C17 n-alkanes, characterized in that, Includes the following steps: Animal and vegetable oils undergo hydrodecarbonylation and decarboxylation reactions under the action of a hydrodecarbonylation and decarboxylation catalyst to obtain bio-based C17 n-alkanes; The preparation method of the hydrogenation decarbonylation and decarboxylation catalyst includes: Step 1: Mix magnesium aluminum spinel, TiO2 and β molecular sieve, grind them, then mix them with a binder, shape them and calcine them to obtain a hydrogenation decarbonylation and decarboxylation catalyst support; Step 2: The active component is loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support to obtain the hydrogenation decarbonylation and decarboxylation catalyst; The mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.05~0.5:1.0~5.

0.

2. The method for preparing bio-based C17 n-alkanes according to claim 1, characterized in that, The preparation method of magnesium aluminum spinel includes the following steps: Magnesium salt, aluminum salt and template agent are mixed to form a solution, and a precipitant is used to carry out a precipitation reaction to obtain a precipitate. The precipitate is then dried and calcined to obtain magnesium aluminum spinel.

3. The method for preparing bio-based C17 n-alkanes according to claim 2, characterized in that, Magnesium salts and aluminum salts are mixed with an acid solution to obtain solution A. A template agent is mixed with water to obtain solution B. Then, solutions A and B are mixed, and a precipitating agent is added to carry out a precipitation reaction to obtain a precipitate.

4. The method for preparing bio-based C17 n-alkanes according to claim 1, characterized in that, Step 1 also involves mixing at least one of guar gum powder, adhesive solvent, and dispersant, wherein the binder is boehmite.

5. The method for preparing bio-based C17 n-alkanes according to claim 4, characterized in that, The mass ratio of the mixture of magnesium aluminum spinel, TiO2, and β molecular sieve to the binder and guar gum powder is 60:30-50:1-5; the adhesive solvent is an aqueous solution of nitric acid, and the dispersant is an aqueous solution of citric acid; the calcination temperature in step 1 is 450-550℃, and the calcination time is 4-6 h.

6. The method for preparing bio-based C17 n-alkanes according to claim 1, characterized in that, The active components are loaded onto the hydrogenation decarbonylation and decarboxylation catalyst support by impregnation, and the active components are molybdenum and nickel.

7. The method for preparing bio-based C17 n-alkanes according to claim 6, characterized in that, The molar ratio of molybdenum to nickel is 0.15~0.25:1, and the roasting temperature in step 2 is 500~600℃, and the roasting time is 4~8h.

8. The method for preparing bio-based C17 n-alkanes according to claim 1, characterized in that, Based on a total mass of 100 parts for the hydrodecarbonylation and decarboxylation catalyst support, and considering the active component as a metal oxide, the active component in the hydrodecarbonylation and decarboxylation catalyst is 20-30 parts by mass; the mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.1-0.2:1.5-2.

5.

9. The method for preparing bio-based C17 n-alkanes according to claim 1, characterized in that, In the hydrogenation decarbonylation and decarboxylation catalyst, the active components are molybdenum and nickel, and the molybdenum:nickel molar ratio is 0.10~0.3:1; Before the animal and vegetable oils undergo hydrogenation decarbonylation and decarboxylation reactions, they are first subjected to a hydrogenation pre-purification reaction. The preparation method of the hydrogenation pre-purification catalyst includes: Step 1': Mix magnesium aluminum spinel, TiO2 and β molecular sieve, grind them, then mix them with a binder, shape them and calcine them to obtain a hydrogenation pre-purified catalyst support; Step 2': The active component is loaded onto the hydrogenation pre-purification catalyst support to obtain the hydrogenation pre-purification catalyst; The mass ratio of magnesium aluminum spinel, TiO2, and β molecular sieve is 100:0.05~0.5:1.0~5.0; the active components in the hydrogenation pre-purification catalyst are molybdenum and nickel, and the molybdenum:nickel molar ratio is 1~4:

1.

10. The method for preparing bio-based C17 n-alkanes according to claim 9, characterized in that, The animal and vegetable oils are at least one of castor oil, cottonseed oil, tung oil, and palm oil; the temperature of the hydrogenation decarbonylation and decarboxylation reaction is 300~400℃, the pressure is 1.5~3MPa, and the hydrogen-to-oil volume ratio is 150~800:1; the temperature of the hydrogenation pre-refining reaction is 80~200℃, the pressure is 1.5~3MPa, and the hydrogen-to-oil volume ratio is 150~800:

1.

11. The method for preparing bio-based C17 n-alkanes according to claim 9, characterized in that, Based on 100 parts of the total mass of the hydrodecarbonylation and decarboxylation catalyst support, the mass of molybdenum and nickel in the hydrodecarbonylation and decarboxylation catalyst is 20-30 parts, calculated as MoO3 and NiO respectively; based on 100 parts of the mass of the hydropre-purified catalyst support, the mass of molybdenum and nickel in the hydropre-purified catalyst is 10-15 parts, calculated as MoO3 and NiO respectively.

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