Method for preparing linear alcohol by utilizing biomass-based derivative

Abstract

The invention discloses a method for preparing linear alcohol from biomass-based derivatives, and belongs to the technical field of energy chemistry. According to the method, multiple biomass-based derivatives are taken as substrates, a RuCo / SBA-15 bimetallic catalyst and 1, 4-dioxane are added into a reactor in proportion, under certain reaction conditions, the substrates can be subjected to selective ring-opening hydrogenolysis, the linear alcohol is efficiently prepared, the yield reaches 80% or above, and the selectivity is at least 80%. The method solves the problem of low selectivity caused by multi-step competitive reaction, has the advantages of low cost, high catalytic efficiency, simple process and the like, and has strategic value for promoting the development of carbon cycle economy.

Description

Technical Field

[0001] This invention belongs to the field of energy chemistry technology, specifically relating to a method for preparing linear alcohols using biomass-based derivatives. Background Technology

[0002] Linear alcohols, as linear alcohol compounds with typical straight-chain structures, play an important role as multifunctional structural units in the industrial field. Among them, 2,5-hexanediol, with its dihydroxyl functional group, is widely used in the synthesis system of polymers such as polyethers, polyesters, and polyurethanes. It is also a key precursor for pharmaceutical intermediates and cosmetic raw materials (Zhang L, Li X, Wang J, et al. Iodine-modified Pt nanoparticles accelerate the hydrogenative ring-opening of furfurals to linear alcohols[J]. AIChE Journal, 2023.). 2-Hexanol, due to its monohydroxy linear molecular structure, can be used as a diesel blending component, lubricating oil base oil, or surfactant raw material in the preparation of functional chemicals through catalytic conversion or molecular compounding technology (Hu X, Li Z, Wang H, et al. Selective Hydrogenolysis of 5-Hydroxymethylfurfural to 2-Hexanol over Au / ZrO[J]. ChemSusChem, 2022, 15(13): e202200092.). 1,4-Pentanediol, like other biodiols, is a component of biodegradable polyesters and plastics. 1,4-Pentanediol can combine with long-chain diacids (>C12) to form crystalline polyesters, which, due to their low switching temperature (<0℃), are suitable for developing shape memory polymers. This unique heat-sensitive adhesive has broad application potential in the packaging of temperature-sensitive goods, adhesives, coatings, and elastic / rubber materials. In addition, 1,4-pentanediol is also widely used as an industrial solvent (Zhu S, Lv Z, Wang J, et al. Catalytic production of 1,4-pentanediol from lignocellulosic biomass[J]. Green Chemistry, 2024, 26(14):16.). 1,2-pentanediol, as an important chemical substance, is widely used in the manufacture of polyesters, the production of the bactericide propiconazole, and as an antibacterial agent in cosmetics due to its excellent solubility (Wang J, Zhu S, et al. Pt / Mg x AlO ybifunctional catalysts with various Mg / Al ratios for selective hydrogenation of furfural alcohol to 1,2-pentanediol[J]. Catalysis Today, 2024, 433: 114647.).

[0003] It is worth noting that, driven by global "dual carbon" goals, the linear alcohol production industry faces an urgent need to optimize its carbon footprint. Given the renewable nature of oxygen-containing biomass resources, achieving the green preparation of linear alcohols through bioconversion or catalytic upgrading processes not only aligns with the development trend of sustainable chemistry, but also holds strategic value in promoting the development of a carbon circular economy, both in terms of technological innovation in the exploration of reaction mechanisms in academic research and in large-scale production applications in industrial practice.

[0004] Existing research indicates that constructing high-yield linear alcohol systems using biomass-based platform molecules as substrates via a one-pot method remains highly challenging, despite the theoretical advantages of this strategy in terms of atom economy and energy consumption control. Specifically, the direct conversion from biomass derivatives to linear alcohols involves multiple competing reactions: deep hydrogenation of aldehyde functional groups, hydrogenolytic cleavage of hydroxyl sites, and ring-opening isomerization of the furan ring system. Insufficient synergistic regulation of these processes can lead to a significant decrease in the selectivity of the target product (Zhang L, Li X, Wang J, et al. Iodine-modified Pt nanoparticles accelerate the hydrogenative ring-opening of furfurals to linear alcohols[J]. AIChEJournal, 2023.). Currently, developing linear alcohol preparation technologies that combine cost-effectiveness, catalytic efficiency, and process simplicity requires not only overcoming the bottleneck of structure-activity relationship regulation among multiple active sites but also achieving precise product guidance in catalytic system design. Technological innovation in this area has become an urgent breakthrough direction for green synthetic chemistry. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a one-step method for preparing linear alcohols using biomass-based derivatives. This method solves the problem of low selectivity caused by multi-step competing reactions and has advantages such as low cost, high catalytic efficiency, and simple process, which is of strategic value for promoting the development of a carbon circular economy.

[0006] On one hand, the present invention provides a method for preparing linear alcohols using biomass-based derivatives, comprising the following steps: using biomass-based derivatives as substrates, adding them, along with a catalyst and 1,4-dioxane in a certain proportion to a reactor, and carrying out a ring-opening hydrogenolysis reaction under certain reaction conditions through the action of external hydrogen gas, wherein the catalyst is a metal mesoporous molecular sieve.

[0007] Specifically, the metal mesoporous molecular sieve can be a monometallic mesoporous molecular sieve or a bimetallic mesoporous molecular sieve. The monometallic supported mesoporous molecular sieve is Co / SBA-15, and the bimetallic supported mesoporous molecular sieve is RuCo / SBA-15, PdCo / SBA-15, NiCo / SBA-15, CuCo / SBA-15, and / or PtCo / SBA-15, preferably RuCo / SBA-15.

[0008] Specifically, the biomass-based derivatives include 5-hydroxymethylfurfural, 5-methylfurfural, furfural, furfuryl alcohol, 2,5-furandiethanol, 5-methyl-2-furanethanol, 2,5-dimethylfuran and / or 2-methylfuran.

[0009] Specifically, the linear alcohol is 2,5-hexanediol, 2-hexanol, 1,4-pentanediol, 1,2-pentanediol and / or n-pentanol.

[0010] Specifically, the reaction ratio of the substrate, catalyst and 1,4-dioxane is 0.05-0.35g:0.15-0.85g:10mL, preferably 0.06-0.25g:0.025-0.075g:10mL.

[0011] Specifically, the reaction conditions are: reaction temperature of 100–180℃, hydrogen pressure of 0.05–5.0 MPa, stirring speed of 200–1000 rpm, and reaction time of 3–6 h.

[0012] Preferably, the reaction temperature is 110–170°C, more preferably 120–160°C;

[0013] Preferably, the pressure is 0.1–3.0 MPa;

[0014] Preferably, the stirring speed is 300-900 rpm, more preferably 400-800 rpm.

[0015] Specifically, the reactor is a closed reactor, such as a stainless steel closed reactor.

[0016] On one hand, the present invention uses the above method to prepare linear alcohols, wherein the linear alcohols are 2,5-hexanediol, 2-hexanol, 1,4-pentanediol, 1,2-pentanediol and / or n-pentanol.

[0017] On the one hand, the present invention provides the use of the linear alcohol in the synthesis of polyethers, polyesters or polyurethanes.

[0018] On the other hand, the linear alcohol described in this invention is used in the preparation of pharmaceutical intermediates or cosmetic raw materials.

[0019] Beneficial Effects: This invention utilizes a bimetallic catalyst supported on a mesoporous molecular sieve to synthesize linear alcohols from biomass-based derivatives in a one-pot process under exogenous hydrogen conditions. The product exhibits high selectivity and yield (over 80%), with a selectivity of at least 80% and a short reaction time. This method solves the problem of low selectivity caused by multi-step competing reactions and offers advantages such as low cost, high catalytic efficiency, and simple process, making it strategically valuable for promoting the development of a carbon circular economy. Attached Figure Description

[0020] Figure 1 This is the gas chromatogram of the linear alcohols (2,5-hexanediol and 2-hexanol) prepared in Example 1 of the present invention.

[0021] Figure 2 The gas chromatograms of the linear alcohols (1,4-pentanediol, 1,2-pentanediol and pentanol) prepared in Example 8 of this invention are shown. Detailed Implementation

[0022] Detailed Description of Embodiments. The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description unfolds. However, these embodiments are merely illustrative and do not constitute any limitation on the scope of protection defined by the claims of the present invention.

[0023] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0025] Example 1: Effect of different catalysts on the yield of linear alcohols

[0026] Using 5-hydroxymethylfurfural (HMF) as a substrate, the catalytic effects of different catalysts were compared. The specific operating steps are as follows:

[0027] 0.126 g of 5-hydroxymethylfurfural, 0.05 g of catalyst, and 10 mL of 1,4-dioxane were added to a stainless steel sealed reactor, which was then purged with 1 MPa H2 and reacted at 150 °C for 4 h with stirring at 600 rpm. After the reaction, the mixture was cooled to room temperature. Solid-liquid separation was performed using a centrifuge (8000 rpm, 5 min), and quantitative analysis was performed using a gas chromatograph (GC, Agilent 7890A). The conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity were calculated based on the gas chromatographic analysis. The effect of the catalyst on the yield and selectivity of the linear alcohol was further investigated. The gas chromatograms of the prepared linear alcohols (2,5-hexanediol and 2-hexanol) are shown below. Figure 1 As shown.

[0028] Table 1 shows that, compared to other supports (SiO2, CeO2, ZSM-5, Al2O3, and TiO2), loading cobalt onto SBA-15 mesoporous molecular sieve resulted in ring-opening products, with a linear alcohol yield of 10%. Subsequently, Ru, Pd, Pt, Cu, and Ni were also loaded onto Co / SBA-15 to construct a bimetallic system ruthenium-cobalt / mesoporous molecular sieve (RuCo / SBA-15). The results indicate that the RuCo / SBA-15 catalyst not only achieved complete HMF conversion without producing the intermediate 2,5-dimethylfuran, but also achieved a linear alcohol yield as high as 81%. The RuCo / SBA-15 catalyst was used in subsequent experiments.

[0029] Table 1. Effect of different catalysts on the yield of linear alcohols

[0030] Example 2: Effect of different solvents on the yield of linear alcohols

[0031] The specific steps for comparing the effects of different solvents on the yield of linear alcohols are as follows:

[0032] Referring to Example 1, 0.05 g of RuCo / SBA-15 was selected as the catalyst, and the reaction was carried out under different solvent conditions. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0033] Table 2 shows that the catalyst can ring-open 5-hydroxymethylfurfural in different solvents, but the linear alcohol yields vary. The ruthenium-cobalt / mesoporous molecular sieve (RuCo / SBA-15) catalyst exhibits the best catalytic effect in 1,4-dioxane, achieving a 100% conversion of 5-hydroxymethylfurfural and a linear alcohol yield as high as 81%. The solvent 1,4-dioxane was used in subsequent experiments.

[0034] Table 2. Effect of different solvents on the yield of linear alcohols

[0035]

[0036] Example 3: Effect of different reaction temperatures on the yield of linear alcohols

[0037] The specific operating steps for the comparative experiment at different reaction temperatures are as follows:

[0038] Referring to Example 2, 10 mL of 1,4-dioxane was selected as the reaction solvent, and the reaction was carried out under different temperature conditions. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0039] Table 3 shows that the conversion rate of 5-hydroxymethylfurfural reaches 100% when the temperature reaches 120℃, at which point the yield of 2,5-dimethylfuran is 47%, and the yield of linear alcohol is 29%. With increasing reaction temperature, the yield of 2,5-dimethylfuran decreases; the yield and selectivity of linear alcohol first increase and then decrease with increasing reaction temperature, reaching a maximum of 81% and a maximum selectivity of 81% at a reaction temperature of 150℃. The reaction temperature of 150℃ will be used in subsequent experiments.

[0040] Table 3. Effect of different reaction temperatures on the yield of linear alcohols

[0041] Example 4: Effect of different hydrogen pressures on the yield of linear alcohols

[0042] The specific operating steps for the comparative experiment of different hydrogen pressures are as follows:

[0043] Referring to Example 3, the reaction was carried out under different hydrogen pressure atmospheres and stirred at 600 rpm at 150°C for 4 h. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0044] Table 4 shows that HMF can be completely converted at a hydrogen pressure of 0.1 MPa, indicating that the amount of hydrogen is sufficient during the reaction. However, with increasing hydrogen pressure, the yield and selectivity of the linear alcohol show a trend of first increasing and then decreasing, indicating that hydrogen pressure affects the product distribution. The linear alcohol has the highest yield and best selectivity at a hydrogen pressure of 0.9 MPa, and this product was used in subsequent experiments.

[0045] Table 4. Effect of different hydrogen pressures on the yield of linear alcohols

[0046] Example 5: Effect of different stirring speeds on the yield of linear alcohols

[0047] The specific operating steps for the comparative experiment of different stirring speeds are as follows:

[0048] Based on Examples 1-3, and referring to Example 4, the hydrogen pressure was selected as 0.9 MPa, and the reaction was carried out under different stirring speeds. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0049] As shown in Table 5, the conversion rate of 5-hydroxymethylfurfural gradually increased with the increase of stirring speed, eventually reaching complete conversion; the yield and selectivity of linear alcohols increased with the increase of stirring speed, reaching the best at 600 rpm, and were used in subsequent experiments.

[0050] Table 5. Effect of different stirring speeds on the yield of linear alcohols

[0051]

[0052] Example 6: Effect of different RuCo / SBA-15 dosages on linear alcohol yield

[0053] The specific operating steps for the comparative experiment on the dosage of different catalysts are as follows:

[0054] Referring to Example 5, the reaction was carried out at a stirring speed of 600 rpm under different RuCo / SBA-15 dosage conditions. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0055] As shown in Table 6, the conversion rate of 5-hydroxymethylfurfural gradually increased with the increase of RuCo / SBA-15 dosage, eventually reaching complete conversion; the yield of linear alcohol showed a trend of first increasing and then decreasing with the increase of RuCo / SBA-15 dosage, reaching the best under the condition of 0.05g. In subsequent experiments, the dosage of RuCo / SBA-15 was selected as 0.05g.

[0056] Table 6. Effect of different RuCo / SBA-15 dosages on linear alcohol yield

[0057] Example 7: Effect of different 5-hydroxymethylfurfural dosages on the yield of linear alcohols

[0058] The specific operating procedures for the comparative experiment of different dosages of 5-hydroxymethylfurfural are as follows:

[0059] Referring to Example 6, the dosage of RuCo / SBA-15 was selected as 0.05 g, and the reaction was carried out under different dosages of 5-hydroxymethylfurfural. Gas chromatography analysis was used to calculate the conversion rate of 5-hydroxymethylfurfural, the molar yield of the linear alcohol, and the selectivity, further investigating the effect of the catalyst on the yield and selectivity of the linear alcohol.

[0060] As shown in Table 7, the conversion rate of 5-hydroxymethylfurfural decreased with increasing dosage; the yield of the linear alcohol first increased and then decreased with increasing dosage. Considering substrate conversion, product yield, and cost, the dosage of 5-hydroxymethylfurfural was selected as 0.126 g.

[0061] Table 7. Effect of different 5-hydroxymethylfurfural dosages on linear alcohol yield

[0062] Example 8: Effect of different substrates on the yield of linear alcohols

[0063] The specific operating steps for the comparative experiment with different substrates are as follows:

[0064] Referring to Example 7, the substrate dosage was selected as 1 mmol (0.082–0.128 g), and the reaction was carried out under different substrate conditions. Gas chromatography analysis was performed to calculate the substrate conversion, linear alcohol molar yield, and selectivity. The effect of the catalyst on the yield and selectivity of the linear alcohols was further investigated. The gas chromatograms of the prepared linear alcohols (1,4-pentanediol, 1,2-pentanediol, and pentanol) are shown below. Figure 2 As shown.

[0065] As shown in Tables 8-9, the conversion rates of the substrates were all 100%. When the substrate was 2,5-dimethylfuran, the yield and selectivity of the linear alcohols were as high as 90%. Under the same conditions, other reaction substrates could also produce linear alcohols, with yields of no less than 80%.

[0066] Table 8. Effect of different substrates on the yield of linear alcohols

[0067]

[0068]

[0069] Table 9. Effect of different substrates on the yield of linear alcohols

[0070]

[0071] Through further optimization and screening of the examples, under the conditions of 150°C, 4 h reaction time, 0.9 MPa H2, and 600 rpm, 0.05 g RuCo / SBA-15 catalyst can completely hydrogenolyze 1 mmol of biomass-based derivatives (5-hydroxymethylfurfural, 5-methylfurfural, furfural, furfuryl alcohol, 2,5-furandiethanol, 5-methyl-2-furanethanol, 2,5-dimethylfuran, 2-methylfuran) to form linear alcohols (2,5-hexanediol, 1,4-pentanediol, etc.) in yields of over 80%. Under these reaction conditions, the selectivity for the formation of linear alcohols (2,5-hexanediol, 2-hexanol, 1,4-pentanediol, 1,2-pentanediol, pentanol) is at least 80%.

[0072] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing linear alcohols using biomass-based derivatives, characterized in that, The process includes the following steps: using a biomass-based derivative as a substrate, adding it, a catalyst, and 1,4-dioxane to a reactor, and carrying out a ring-opening hydrogenolysis reaction through the action of external hydrogen gas. The catalyst is a metal-supported mesoporous molecular sieve.

2. The method according to claim 1, characterized in that, The metal-loaded mesoporous molecular sieve is a monometallic-loaded mesoporous molecular sieve or a bimetallic-loaded mesoporous molecular sieve. The monometallic-loaded mesoporous molecular sieve is Co / SBA-15, and the bimetallic-loaded mesoporous molecular sieve is RuCo / SBA-15, PdCo / SBA-15, NiCo / SBA-15, CuCo / SBA-15, and / or PtCo / SBA-15, preferably RuCo / SBA-15.

3. The method according to claim 2, characterized in that, The biomass-based derivative is selected from one or more of 5-hydroxymethylfurfural, 5-methylfurfural, furfural, furfuryl alcohol, 2,5-furandiethanol, 5-methyl-2-furanethanol, 2,5-dimethylfuran, and 2-methylfuran.

4. The method according to claim 3, characterized in that, The linear alcohol is selected from one or more of 2,5-hexanediol, 2-hexanol, 1,4-pentanediol, 1,2-pentanediol, and n-pentanol.

5. The method according to claim 1, characterized in that, The reaction ratio of substrate, catalyst and 1,4-dioxane is 0.05-0.35 g: 0.15-0.85 g: 10 mL, preferably 0.06-0.25 g: 0.025-0.075 g: 10 mL.

6. The method according to claim 1, characterized in that, The reaction conditions were: reaction temperature 100–180℃, hydrogen pressure 0.05–5.0 MPa, stirring speed 200–1000 rpm, and reaction time 3–6 h. Preferably, the reaction temperature is 110–170°C, more preferably 120–160°C; Preferably, the pressure is 0.1–3.0 MPa; Preferably, the stirring speed is 300-900 rpm, more preferably 400-800 rpm.

7. The method according to claim 1, characterized in that, The reactor is a closed reactor, such as a stainless steel closed reactor.

8. The method according to any one of claims 1-7 prepares a linear alcohol, wherein the linear alcohol is 2,5-hexanediol, 2-hexanol, 1,4-pentanediol, 1,2-pentanediol and / or n-pentanol.

9. The use of the linear alcohol of claim 8 in the synthesis of polyethers, polyesters or polyurethanes.

10. The use of the linear alcohol according to claim 8 in the preparation of pharmaceutical intermediates or cosmetic raw materials.

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