A method for preparing a biomass-based polyalkyl-substituted cyclopentane structured lubricating oil

Abstract

The application discloses a preparation method of biomass-based multi-alkyl-substituted cyclopentane structure lubricating oil and belongs to the field of organic synthesis. The multi-alkyl-substituted cyclopentane structure lubricating oil precursor is prepared from 2-undecanone and 5-methyl furfural through hydroxy aldehyde condensation and [2+2] cycloaddition reaction of the 2-undecanone and 5-methyl furfural, and the multi-alkyl-substituted cyclopentane structure lubricating oil is obtained through further hydrogenation and deoxidization. The multi-alkyl-substituted cyclopentane structure lubricating oil precursor has a high-tension four-membered ring structure, and the hydrogenation and deoxidization is carried out under the co-catalysis of an activated carbon supported metal hydrogenation catalyst and a molecular sieve, a heteropoly acid or alumina, and a high-performance cyclopentane structure lubricating oil is obtained through a skeleton rearrangement process. The lubricating oil has a kinematic viscosity (40 DEG C) of 14.25 mm 2 / s, a kinematic viscosity (100 DEG C) of 3.49 mm 2 / s.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, specifically relating to a method for preparing a biomass-based polyalkyl-substituted cyclopentane structure lubricating oil. Background Technology

[0002] Biomass-based lubricating oils are environmentally friendly lubricants manufactured using clean raw materials, achieving emission reduction, and directly applicable to the friction contact surfaces of equipment. The hydrodeoxygenation of lubricating oil precursors typically utilizes activated carbon-supported noble metal hydrogenation catalysts and catalysts such as molecular sieves, heteropoly acids, or alumina. Photocatalysis is widely used for the high-value conversion and utilization of biomass molecules, such as fuel precursors and material monomer synthesis. Compared to traditional thermocatalytic organic reactions, photocatalysis is environmentally friendly and can synthesize structures that are difficult to achieve through thermocatalysis, such as four-membered rings.

[0003] Polyalkyl-substituted cyclopentanes (MACs) are near-monomer synthetic hydrocarbons. Their cyclic molecular structure gives them better anti-wear properties than perfluoropolyethers (PFPEs), making them a potential high-performance lubricant alternative to PFPEs. Traditional MAC synthesis uses petroleum-based feedstocks, leading to significant carbon emissions and related environmental impacts. Therefore, there is an urgent need to develop high-performance lubricants derived from sustainable resources such as biomass.

[0004] Biomass-based polyalkylcyclopentane lubricants draw their feedstock from waste oils, municipal waste, agricultural and forestry waste, energy crops, and renewable electricity. Compared to traditional petroleum-based lubricants, biomass-based lubricants can reduce carbon dioxide emissions by more than 80% throughout their entire lifecycle. Biomass-based lubricants are defined as low-toxicity or non-toxic biodegradable products with zero CO2 emissions, and their feedstocks are renewable. Biomass-based lubricants can reduce dependence on fossil fuels and achieve a reduction in carbon emissions throughout their lifecycle. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention provides a method for preparing a biomass-based polyalkyl-substituted cyclopentane lubricating oil. The preparation method of this invention is based on biomass-based polyalkylcyclopentane lubricating oil precursor I and polyalkylcyclopentane lubricating oil precursor II, and can prepare a biomass-based polyalkylcyclopentane lubricating oil.

[0006] The present invention discloses a method for preparing a biomass-based polyalkyl-substituted cyclopentane structure lubricating oil, comprising the following steps:

[0007] Step 1: 5-substituted furanaldehyde and long-chain ketones undergo aldol condensation to generate polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I;

[0008] ;

[0009] In the formula, R1 and R2 are selected from alkyl, cycloalkyl, aryl or hydrogen.

[0010] The preferred reactants are 5-methylfurfural and 2-undecone.

[0011] Step 2: Polyalkyl-substituted cyclopentane lubricating oil condensation precursor I undergoes a [2+2] reaction under light irradiation to generate polyalkyl-substituted cyclopentane lubricating oil condensation precursor II;

[0012] ;

[0013] Step 3: The polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor II is prepared by hydrodeoxygenation to obtain the polyalkyl-substituted cyclopentane structure lubricating oil. The various structures of the product are controlled by adding different catalysts.

[0014] The polyalkyl-substituted cyclopentane structure lubricating oil includes at least one of the compounds shown in formulas (1) to (3). In addition to the compounds with structures shown in formulas (1) to (3), the product may also include at least one of the compounds with structures shown in formulas (4) to (8).

[0015] .

[0016] Furthermore, in step 1:

[0017] Under alkaline conditions at 0°C, 5-substituted furanaldehyde and long-chain ketone undergo aldol condensation in a solvent to yield polyalkyl-substituted cyclopentane lubricating oil condensation precursor I.

[0018] The molar ratio of 5-substituted furanaldehyde to long-chain ketone is (1~1.5):1.

[0019] The alkaline conditions are achieved by adding sodium hydroxide, wherein the molar amount of sodium hydroxide is 0-20 mol% of the total molar amount of 5-substituted furanaldehyde and long-chain ketone, preferably 15 mol%.

[0020] The aldol condensation reaction is carried out at a temperature of -20°C to 200°C for 1 to 24 hours.

[0021] The solvent is selected from at least one of acetonitrile, methanol, ethanol, water, toluene, ethyl acetate, acetone, and dichloromethane.

[0022] The amount of solvent is such that the concentration of polyalkyl-substituted cyclopentane lubricating oil condensation precursor I in the system is 0.05~0.8 mol / L. -1 .

[0023] Furthermore, in step 2:

[0024] Under light irradiation and with or without a catalyst (such as acetic acid), the polyalkyl-substituted cyclopentane lubricating oil condensation precursor I undergoes a [2+2] reaction in a solvent to obtain the polyalkyl-substituted cyclopentane lubricating oil condensation precursor II.

[0025] Before the [2+2] reaction occurs, an inert gas is introduced into the polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I for 0.5 to 2 h.

[0026] The [2+2] reaction is carried out at a temperature of -20℃ to 40℃ for a reaction time of 1 to 24 h.

[0027] The light irradiation is ultraviolet light irradiation.

[0028] The solvent is selected from at least one of acetonitrile, methanol, ethanol, water, toluene, ethyl acetate, acetone, and dichloromethane.

[0029] The amount of solvent is such that the concentration of the polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I is 0.05~0.8 mol / L. -1 .

[0030] Furthermore, in step 3:

[0031] In a hydrogen atmosphere and in the presence of a catalyst, the polyalkyl-substituted cyclopentane lubricating oil condensation precursor II undergoes a hydrodeoxygenation reaction. The hydrogen pressure is 0.5~8 MPa, the hydrodeoxygenation reaction time is 1~18 h, and the temperature is 100~250 °C.

[0032] The catalyst includes one or more of the following: metal-supported alumina catalyst, metal-supported molecular sieve catalyst, and activated carbon-supported noble metal hydrogenation catalyst.

[0033] The metal-supported alumina catalyst includes at least one of Pd@α-Al2O3, Pd@γ-Al2O3, Pt@α-Al2O3, Pt@γ-Al2O3, Ru@α-Al2O3, Ru@γ-Al2O3, Rh@α-Al2O3, and Rh@γ-Al2O3; the metal-supported molecular sieve catalyst includes Pd@HY, Pd@LaY, Pd@CeY, Pd@NaY, Pd@ReY, Pd@NH4Y, Pd@USY, Pd@mesoporous Y, Pd@ZSM-5, Pd@ZSM-35, Pd@MCM, Pd@β, Pd@SAPO, Pt@HY, Pt@LaY, Pt@CeY, Pt@NaY, Pt@ReY, Pt@NH4Y, Pt@USY, Pt@mesoporous Y, Pt@ZSM-5, and P The activated carbon-supported noble metal hydrogenation catalyst comprises at least one of the following: t@ZSM-35, Pt@MCM, Pt@β, Pt@SAPO, Ru@HY, Ru@LaY, Ru@CeY, Ru@NaY, Ru@ReY, Ru@NH4Y, Ru@USY, Ru@mesoporous Y, Ru@ZSM-5, Ru@ZSM-35, Ru@MCM, Ru@β, Ru@SAPO, Rh@HY, Rh@LaY, Rh@CeY, Rh@NaY, Rh@ReY, Rh@NH4Y, Rh@USY, Rh@mesoporous Y, Rh@ZSM-5, Rh@ZSM-35, Rh@MCM, Rh@β, and Rh@SAPO; the activated carbon-supported noble metal hydrogenation catalyst comprises at least one of Pd / C, Pt / C, Ru / C, and Rh / C, wherein the metal content is 0.1% to 10%.

[0034] The alumina includes at least one of α-Al2O3 (10nm, 20nm, 40nm, 60nm) and γ-Al2O3 (10nm, 20nm, 40nm, 60nm).

[0035] Furthermore, the catalyst also includes molecular sieves and / or heteropoly acids.

[0036] The molecular sieve includes at least one of HY, LaY, CeY, NaY, ReY, NH4Y, USY, mesoporous Y, ZSM-5, ZSM-35, MCM, β, and SAPO; the heteropoly acid includes at least one of trifluoromethanesulfonate, silicotungstic acid, phosphotungstic acid, and phosphomolybdic acid.

[0037] The polyalkylcyclopentane structured lubricating oil of this invention can be synthesized in three steps: aldol condensation, room-temperature and atmospheric-pressure photocatalytic cycloaddition, and hydrodeoxygenation. The preparation method of this invention features high yield, mild reaction conditions, a simple reaction process, few byproducts, and low cost for product separation and purification. The prepared polyalkylcyclopentane structured lubricating oil exhibits strong high-temperature oxidation resistance, a high viscosity index, and excellent anti-wear properties, with a kinematic viscosity (40℃) of 14.25 mm. 2 / s, kinematic viscosity (100℃) 3.49 mm 2 / s can be used as a base oil or additive for lubricating oil, promoting the high-value utilization of biomass resources. Attached Figure Description

[0038] Figure 1 The image shows the 1H NMR spectrum of the copolymerization product of 5-methylfurfural and 2-undecone.

[0039] Figure 2 The image shows the carbon NMR spectrum of the copolymerization product of 5-methylfurfural and 2-undecone.

[0040] Figure 3 The image shows the 1H NMR spectrum of the self-polymerization product of polyalkylcyclopentane structure lubricating oil condensation precursor I.

[0041] Figure 4 The image shows the carbon NMR spectrum of the self-polymerization product of polyalkylcyclopentane structure lubricating oil condensation precursor I.

[0042] Figure 5 It is the 1H NMR spectrum of a lubricating oil with a polyalkylcyclopentane structure.

[0043] Figure 6 It is the carbon NMR spectrum of a lubricating oil with a polyalkylcyclopentane structure. Detailed Implementation

[0044] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0045] In one aspect of the present invention, a polyalkylcyclopentane lubricating oil condensation precursor I is provided, the molecular formula of which comprises the following structure:

[0046]

[0047] In the formula, R1 and R2 are selected from alkyl, cycloalkyl, aryl or hydrogen.

[0048] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned polyalkylcyclopentane lubricating oil condensation precursor I, comprising: subjecting a biomass-derived alkyl-substituted furanaldehyde to a long-chain ketone in a solvent under alkaline conditions at 0 °C to undergo an aldol condensation reaction, thereby obtaining the polyalkyl-substituted cyclopentane lubricating oil condensation precursor I.

[0049] It is understood that the above-mentioned alkaline conditions preferably use sodium hydroxide, and the sodium hydroxide content is 0-20% of the furanaldehyde and long-chain ketone, preferably 15%.

[0050] In some embodiments of the present invention, the furfural and long-chain ketone are preferably 5-methylfurfural and 2-undecanone.

[0051] In some embodiments of the present invention, the molecular formula of 5-methylfurfural is: The molecular formula of 2-undecone is The above condensation reaction is an aldol condensation reaction between two reactant molecules, and the specific reaction formula is as follows:

[0052] .

[0053] In some embodiments of the present invention, the molar ratio of 5-methylfurfural to 2-undecone is (1~1.5):1. For example, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, or 1.5:1, etc. Therefore, the appropriate ratio of 5-methylfurfural to 2-undecone can efficiently obtain polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I.

[0054] In some embodiments of the present invention, the aldol condensation reaction is carried out at a temperature of -20 to 200 °C (e.g., -20 °C, -10 °C, 0 °C, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, or 200 °C, etc.) for a time of 1 to 24 h (e.g., 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, or 24 h, etc.). Therefore, the reaction process is simple and the reaction conditions are mild.

[0055] In some embodiments of the present invention, the solvent includes at least one selected from acetonitrile, methanol, ethanol, water, toluene, ethyl acetate, acetone, and dichloromethane. Therefore, the materials are widely available, inexpensive, and do not readily react with the reactants, thus avoiding the introduction of new byproducts.

[0056] In some embodiments of the present invention, the amount of solvent is 0.05~0.8 mol L. -1 Compared to the above concentrations, when the amount of solvent is higher than 0.8 mol / L... -1 When the solvent content is less than 0.05 mol / L, the product yield is lower; when the solvent content is less than 0.05 mol / L, the product yield is lower. -1 If the product yield is too low and the solvent consumption is too high, the solvent loss during separation and purification will be significant.

[0057] In another aspect of the present invention, a polyalkylcyclopentane lubricating oil condensation precursor II is provided, the molecular formula of which comprises the following structure:

[0058]

[0059] In the formula, R1 and R2 are selected from alkyl, cycloalkyl, aryl, or hydrogen. The polyalkylcyclopentane lubricating oil precursor II is prepared using the polyalkylcyclopentane lubricating oil precursor I described above.

[0060] In another aspect of the present invention, the present invention provides a method for preparing the aforementioned polyalkyl cyclopentane lubricating oil precursor II, comprising: subjecting the polyalkyl-substituted cyclopentane lubricating oil condensation precursor I to a [2+2] reaction in a solvent under ultraviolet light irradiation and in the presence or absence of a photocatalyst, to obtain the polyalkyl-substituted cyclopentane lubricating oil precursor II.

[0061] Compared to copolymerization reactions that require photocatalysts, this invention does not require photocatalysts, produces almost no byproducts, and yields a high product yield.

[0062] It is understood that the above-mentioned ultraviolet light irradiation conditions can be provided by a 365nm LED light strip. In some specific embodiments of the present invention, a 365nm LED light strip is used to irradiate the polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I prepared from biomass-derived molecules, causing it to undergo a self-polymerization reaction in a solvent.

[0063] In some embodiments of the present invention, the molecular formula of polyalkyl-substituted cyclopentane lubricating oil condensation precursor II is: The above self-polymerization reaction is a [2+2] cycloaddition reaction between two reactant molecules, and the specific reaction formula is as follows:

[0064] Therefore, polyalkyl-substituted cyclopentane lubricant precursor II can be obtained in high yield through a one-step cycloaddition process.

[0065] It should be noted that the self-polymerization reaction of polyalkyl-substituted cyclopentane lubricating oil condensation precursor I does not require a photocatalyst. If no catalyst is added, the yield of this copolymerization reaction is relatively high. If an acetic acid catalyst is added, the yield can be further improved.

[0066] In some embodiments of the present invention, the copolymerization reaction is carried out at a temperature of -20 to 40°C (e.g., -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, or 40°C), and for a time of 1 to 24 hours (e.g., 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours). Therefore, the reaction process is simple and the reaction conditions are mild.

[0067] In some embodiments of the present invention, the solvent includes at least one selected from acetonitrile, methanol, ethanol, water, toluene, ethyl acetate, acetone, and dichloromethane. Therefore, the materials are widely available, inexpensive, and do not readily react with the reactants, thus avoiding the introduction of new byproducts. The amount of the solvent is 0.05~0.8 mol L. -1 .

[0068] In some embodiments of the present invention, the amount of solvent is 0.05~0.8 mol L. -1 Compared to the above concentrations, when the amount of solvent is higher than 0.8 mol / L... -1 When the solvent content is less than 0.05 mol / L, the product yield is lower; when the solvent content is less than 0.05 mol / L, the product yield is lower. -1 If the product yield is too low and the solvent consumption is too high, the solvent loss during separation and purification will be significant.

[0069] In some embodiments of the present invention, before the copolymerization reaction occurs, an inert gas (e.g., nitrogen) is introduced into the mixture formed by the polyalkyl-substituted cyclopentane lubricating oil condensation precursor I and the solvent for 0.5 to 2 hours (e.g., 0.5 hours, 1 hour, 1.5 hours, or 2 hours). This effectively removes oxygen from the reaction system and reduces the occurrence of side reactions.

[0070] In another aspect of the invention, a polyalkyl-substituted cyclopentane structure lubricating oil is provided, characterized in that the molecular formula of the polyalkyl-substituted cyclopentane structure lubricating oil includes at least one of the molecular formulas shown in formulas (1) to (3). In addition to the compounds with structures shown in formulas (1) to (3), the product may also include at least one of the compounds with structures shown in formulas (4) to (8).

[0071]

[0072] The polyalkyl-substituted cyclopentane structure lubricating oil is prepared using the aforementioned polyalkyl-substituted cyclopentane structure lubricating oil precursor II.

[0073] In another aspect, the present invention provides a method for preparing the aforementioned polyalkyl-substituted cyclopentane structure lubricating oil, comprising: subjecting the aforementioned polyalkyl-substituted cyclopentane structure lubricating oil precursor II to a hydrodeoxygenation reaction to obtain the polyalkyl-substituted cyclopentane structure lubricating oil. Therefore, the reaction process is simple, produces few byproducts, and is suitable for large-scale applications.

[0074] The above-mentioned hydrodeoxygenation reaction reduces the carbonyl group and furan ring in the polyalkyl-substituted cyclopentane lubricant precursor II. At the same time, since the CO bond and carbonyl group of the furan ring are both located at the α position of the high-strain four-membered ring, the molecule will undergo skeletal rearrangement to a certain extent during the hydrodeoxygenation process to generate a lubricant with a polyalkyl-substituted cyclopentane structure.

[0075] In some embodiments of the present invention, the hydrodeoxygenation reaction of the polyalkylcyclopentane structure lubricating oil precursor II includes: under a hydrogen atmosphere, the hydrodeoxygenation reaction of the polyalkylcyclopentane structure lubricating oil precursor II is carried out by one or more of the following: a metal-supported alumina catalyst, a metal-supported molecular sieve catalyst, and an activated carbon-supported noble metal hydrogenation catalyst, in conjunction with a molecular sieve or a heteropolyacid. The hydrogen pressure is 0.5~8 MPa (e.g., 0.5 MPa, 1 MPa, 1.5 MPa, 3 MPa, 5 MPa, or 8 MPa), the hydrodeoxygenation reaction time is 1~18 h (e.g., 1 h, 2 h, 4 h, 8 h, 12 h, or 18 h), and the temperature is 100~250 °C (e.g., 100 °C, 110 °C, 130 °C, 180 °C, or 250 °C). Therefore, the polyalkylcyclopentane structure lubricating oil has a high yield, mild reaction conditions, a simple reaction process, few by-products, and low product separation and purification costs, making it suitable for large-scale applications.

[0076] In some specific embodiments of the present invention, under a hydrogen atmosphere, in the solvent cyclohexane or n-hexane, the polyalkylcyclopentane structure lubricating oil precursor II undergoes a hydrodeoxygenation reaction by one or more of the following: a metal-supported alumina catalyst, a metal-supported molecular sieve catalyst, and an activated carbon-supported noble metal hydrogenation catalyst, in conjunction with a molecular sieve or heteropolyacid.

[0077] In some embodiments of the present invention, the metal-supported alumina catalyst includes at least one of Pd@α-Al2O3, Pd@γ-Al2O3, Pt@α-Al2O3, Pt@γ-Al2O3, Ru@α-Al2O3, Ru@γ-Al2O3, Rh@α-Al2O3, and Rh@γ-Al2O3; the metal-supported molecular sieve catalyst includes Pd@HY, Pd@LaY, Pd@CeY, Pd@NaY, and Pd@ ReY, Pd@NH4Y, Pd@USY, Pd@mesoporous Y, Pd@ZSM-5, Pd@ZSM-35, Pd@MCM, Pd@β, Pd@SAPO, Pt@HY, Pt@LaY, Pt@Ce Y, Pt@NaY, Pt@ReY, Pt@NH4Y, Pt@USY, Pt@mesoporous Y, Pt@ZSM-5, Pt@ZSM-35, Pt@MCM, Pt@β, Pt@SAPO, Ru@HY, R u@LaY, Ru@CeY, Ru@NaY, Ru@ReY, Ru@NH4Y, Ru@USY, Ru@Mesoporous Y, Ru@ZSM-5, Ru@ZSM-35, Ru@MCM, Ru@β, Ru@ SAPO, Rh@HY, Rh@LaY, Rh@CeY, Rh@NaY, Rh@ReY, Rh@NH4Y, Rh@USY, Rh@mesoporousY, Rh@ZSM-5, Rh@ZSM-35, Rh@ At least one of MCM, Rh@β, and Rh@SAPO; the activated carbon-supported noble metal hydrogenation catalyst includes at least one of Pd / C, Pt / C, Ru / C, and Rh / C; the molecular sieve includes at least one of HY, LaY, CeY, NaY, ReY, NH4Y, USY, mesoporous Y, ZSM-5, ZSM-35, MCM, β, and SAPO; the heteropolyacid includes at least one of trifluoromethanesulfonate, silicotungstic acid, phosphotungstic acid, and phosphomolybdic acid. The above-mentioned synthesis steps for the supported catalyst involve immersing the support in a solution containing a metal salt precursor (such as PdCl2, Pd(NO3)2, H2PtCl6, Pt(NO3)2, RuCl3, Ru(NO3)3, RhCl3, Rh(NO3)3, etc.), stirring thoroughly for 4 hours to allow the metal species to adsorb onto the support surface, then drying at 120°C for 12 hours, calcining at 500°C in air for 6 hours, and reducing with 10% H2 / Ar at 500°C for 2 hours to obtain the catalyst. The preferred metal loading is 5 wt%, and the catalyst addition is 2 wt% to 50 wt% of the lubricating oil precursor. Therefore, the above-mentioned activated carbon-supported noble metal hydrogenation catalyst, in combination with molecular sieves or heteropolyacids, can effectively improve the yield of polyalkylcyclopentane structure lubricating oils.

[0078] The preparation method of this invention has high yield, mild reaction conditions, simple reaction process, few by-products, and low cost of product separation and purification, making it suitable for large-scale application.

[0079] In polyalkylcyclopentane structure lubricating oil molecules, according to NMR (nuclear magnetic resonance imaging) Figure 5 , Figure 6 The significant difference in chemical shifts between the two sets of peaks corresponding to H and C on the ring at the lowest field indicates that the lubricating oil molecule has an asymmetric, five-membered ring structure. If the four-membered ring structure is retained, the molecular structure is symmetrical, and the chemical shifts of the two sets of peaks at the lowest field should be consistent.

[0080] Example 1:

[0081] The preparation method of the polyalkylcyclopentane structure lubricating oil in this embodiment includes the following steps:

[0082] Step 1: Preparation of polyalkylcyclopentane structured lubricating oil precursor I

[0083] In a 250 mL flask, 3.73 mL (45 mmol) of 5-methylfurfural and 8.2 mL (40 mmol) of 2-undecane were added, followed by 50 mL of methanol and 40 mL of water. The flask was placed in a Dewar flask, which was then kept at 0°C by immersing it in ice water. An alkaline solution (0.3 M) of 480 mg NaOH and 40 mL of water was prepared and slowly added dropwise to the mixture using a constant pressure funnel. After complete addition at 0°C, the flask was placed in an 80°C metal bath with a reflux apparatus and the reaction was allowed to proceed overnight (12 h). The reaction was scaled up to a 40 mmol scale while maintaining a 75% product yield. The parallel multiple-tube reaction mixture was collected in a 500 mL rotary evaporator, and the solvent was evaporated using a rotary evaporator to obtain a concentrated solution containing a polyalkylcyclopentane structure lubricating oil precursor I. The concentrated solution was analyzed by gas chromatography.

[0084] The structure of polyalkylcyclopentane structure lubricant condensation precursor I is shown below:

[0085] .

[0086] Step 2: Prepare polyalkyl-substituted cyclopentane lubricating oil condensation precursor II using polyalkyl-cyclopentane structure lubricating oil precursor I.

[0087] 1 mmol of polyalkylcyclopentane-structured lubricating oil precursor I was added to a Schlenk tube in 2.5 mL of acetonitrile, and argon gas was introduced for protection. The reactor was irradiated with an LED lamp at a wavelength of 365 nm for 15 h to obtain the reaction solution. The reaction solution was analyzed by gas chromatography-mass spectrometry (GC-MS) to identify the product and calculate the product yield, which was 67%. The parallel multiple-tube reaction solution was collected into a 500 mL rotary evaporator flask, and the solvent was evaporated using a rotary evaporator to obtain a concentrated solution containing polyalkyl-substituted cyclopentane-structured lubricating oil condensation precursor II. The concentrated solution was analyzed by gas chromatography.

[0088] The structure of polyalkyl-substituted cyclopentane lubricant condensation precursor II is shown below:

[0089] .

[0090] Step 3: Preparation of polyalkylcyclopentane structured lubricating oil using polyalkylcyclopentane structured lubricating oil precursor II

[0091] Take 3 g of the concentrated solution and place it in a 500 mL hydrogenation reactor. Add 100 mL of cyclohexane and mix thoroughly. Add 2% Pd@γ-Al2O3 catalyst (γ-Al2O3 mesh size 100-200) at 25 wt% of the lubricating oil precursor. After mixing, seal the hydrogenation reactor and purge it three times with 3 MPa nitrogen. Then purge it three times with 3 MPa hydrogen. Finally, inject 6 MPa of hydrogen into the hydrogenation reactor, seal it, start stirring, and set the heating program to increase the temperature to 220℃ at 5 ℃ / min. Then, maintain the temperature for 15 h. During hydrogenation, frequently observe the pressure gauge. When the pressure in the hydrogenation reactor drops suddenly, replenish the pressure with hydrogen to 6 MPa every 2 hours. Samples were taken from the sampling port, and the hydrogenation reaction process was determined by chromatography. Once the raw material conversion exceeded 90% and the pressure inside the hydrogenation reactor no longer changed significantly, heating was stopped, and the reactor was allowed to cool naturally to room temperature. The reactor was then depressurized, the reaction liquid was removed, and the Pd@γ-Al2O3 catalyst was removed by centrifugation. The solvent was then removed by rotary evaporation, and the product was purified by distillation to obtain a polyalkylcyclopentane structure lubricating oil. The yield of the polyalkylcyclopentane structure lubricating oil was 94%, and the carbon yield was 93%. The product was analyzed using gas chromatography-mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectroscopy to determine its structure and purity.

[0092] The product's molecular formula contains the following structure:

[0093]

[0094] Where (1): (2): (3) = 2%: 3%: 95% (molar ratio).

[0095] Example 2:

[0096] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrodeoxygenation reaction is replaced with a Pd / C+Hf(OTf)4 catalyst, wherein 25wt% Pd / C and 10wt% Hf(OTf)4.

[0097] The product's molecular formula contains the following structure:

[0098]

[0099] Where (1): (2): (3) = 7%: 8%: 85% (molar ratio).

[0100] Example 3: The reaction conditions in this example are the same as in Example 1, except that the catalyst added in step 3 for the hydrogenation deoxygenation reaction is replaced with Pt@α-Al2O3 (α-Al2O3 with a mesh size of 100-200) catalyst.

[0101] The product's molecular formula contains the following structure:

[0102]

[0103] Where (2): (8) = 15%: 85% (molar ratio).

[0104] Example 4:

[0105] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrogenation deoxygenation reaction is replaced with Pt@γ-Al2O3 (γ-Al2O3 with a mesh size of 200-300) catalyst.

[0106] The product's molecular formula contains the following structure:

[0107]

[0108] Where (8): (1): (2) = 65%: 19%: 16% (molar ratio).

[0109] Example 5:

[0110] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrodeoxygenation reaction is replaced with a Pd / C + silicotungstic acid catalyst, wherein 25wt% Pd / C and 10wt% silicotungstic acid are used.

[0111] The product's molecular formula contains the following structure:

[0112]

[0113] Where (1): (2): (3) = 3%: 5%: 92% (molar ratio).

[0114] Example 6:

[0115] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrogenation deoxygenation reaction is replaced with Ru@γ-Al2O3 (γ-Al2O3 with a mesh size of 200-300) catalyst.

[0116] The product's molecular formula contains the following structure:

[0117]

[0118] Where (2): (3): (4) = 12%: 81%: 7% (molar ratio).

[0119] Example 7:

[0120] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrodeoxygenation reaction is replaced with a Pd@USY catalyst.

[0121] The product's molecular formula contains the following structure:

[0122]

[0123] Where (2): (8) = 20%: 80% (molar ratio).

[0124] Example 8:

[0125] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrodeoxygenation reaction is replaced with Pd@ZSM-5 catalyst.

[0126] The product's molecular formula contains the following structure:

[0127]

[0128] Where (2): (3): (4) = 11%: 82%: 7% (molar ratio).

[0129] Example 9:

[0130] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrogenation deoxygenation reaction is replaced with Rh@γ-Al2O3 catalyst.

[0131] The product's molecular formula contains the following structure:

[0132]

[0133] Where (2): (3): (4) = 10%: 84%: 6% (molar ratio).

[0134] Example 10:

[0135] The reaction conditions in this embodiment are the same as in Example 1, except that the catalyst added in step 3 for the hydrodeoxygenation reaction is replaced with a Pd / C catalyst.

[0136] The product's molecular formula contains the following structure:

[0137]

[0138] Where (4): (5): (6): (7) = 10%: 62%: 6%: 22% (molar ratio).

[0139] For any points not covered above, existing technologies shall apply.

[0140] The hydrodeoxygenation catalysis system using Pd@γ-Al2O3 and Pd+ strong acid catalysts (trifluoromethanesulfonate or heteropolyacid) can achieve efficient synthesis of polyalkyl-substituted cyclopentanes, while the Pd-supported molecular sieve catalysis system tends to undergo carbon-carbon cracking. Compared to Pd catalysis systems, Pt catalysis systems are more prone to carbon-carbon bond breakage during hydrodeoxygenation. Ru and Rh catalysis systems are more prone to incomplete hydrogenation during hydrodeoxygenation compared to Pd catalysis systems.

[0141] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0142] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a biomass-based polyalkyl-substituted cyclopentane structure lubricating oil, characterized in that... Includes the following steps: Step 1: 5-substituted furanaldehyde and long-chain ketones undergo aldol condensation to generate polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I; ； In the formula, R1 is a methyl group and R2 is a C8H group. 17 ; Step 2: Polyalkyl-substituted cyclopentane lubricating oil condensation precursor I undergoes a [2+2] reaction under light irradiation to generate polyalkyl-substituted cyclopentane lubricating oil condensation precursor II; ； Step 3: In a hydrogen atmosphere and in the presence of a catalyst, the polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor II undergoes a hydrodeoxygenation reaction to prepare the polyalkyl-substituted cyclopentane structure lubricating oil. The polyalkyl-substituted cyclopentane structured lubricating oil comprises at least one of the compounds with structures shown in formulas (1) to (3): ； The catalyst includes one or more of the following: metal-supported alumina catalyst, metal-supported molecular sieve catalyst, and activated carbon-supported noble metal hydrogenation catalyst. The metal-supported alumina catalyst includes at least one of Pd@α-Al2O3 and Pd@γ-Al2O3; The metal-supported molecular sieve catalyst includes at least one of Pd@HY, Pd@LaY, Pd@CeY, Pd@NaY, Pd@ReY, Pd@NH4Y, Pd@USY, Pd@mesoporousY, Pd@ZSM-5, Pd@ZSM-35, Pd@MCM, Pd@β, and Pd@SAPO; The activated carbon-supported noble metal hydrogenation catalyst is Pd / C and heteropolyacid.

2. The preparation method according to claim 1, characterized in that: In step 1, under alkaline conditions, 5-substituted furanaldehyde and long-chain ketone undergo aldol condensation reaction in a solvent to obtain polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I; The alkaline conditions are achieved by adding sodium hydroxide; The aldol condensation reaction is carried out at a temperature ranging from -20°C to 200°C for 1-24 hours.

3. The preparation method according to claim 1, characterized in that: In step 2, under light irradiation, the polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor I undergoes a [2+2] reaction in a solvent to obtain polyalkyl-substituted cyclopentane structure lubricating oil condensation precursor II; The [2+2] reaction is carried out at a temperature ranging from -20°C to 40°C for 1-24 hours.

4. The preparation method according to claim 1, characterized in that: The hydrogen pressure is 0.5-8 MPa, the hydrogenation and deoxygenation reaction time is 1-18 h, and the temperature is 100-250℃.

5. The preparation method according to claim 1, characterized in that: The heteropoly acid is at least one of trifluoromethanesulfonate, silicotungstic acid, phosphotungstic acid, and phosphomolybdic acid.

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