A solid base catalyst for regulating the aldol condensation process of biomass derivatives and a preparation method and applications thereof
By preparing a Mg-Al-HT/NaY solid base catalyst and combining it with hydrotalcite and NaY molecular sieve, the aldol condensation process of biomass derivatives was regulated, solving the problem of high molecular weight condensation products and achieving high efficiency and stability of the catalyst and synthesis of biomass fuel precursors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2026-02-28
- Publication Date
- 2026-06-05
AI Technical Summary
In existing technologies, the aldol condensation reaction of biomass derivatives easily produces high molecular weight condensation products, leading to low catalyst activity and easy deactivation.
By preparing a Mg-Al-HT/NaY solid base catalyst and combining it with hydrotalcite and NaY molecular sieve, the aldol condensation process was regulated, the basicity of the catalyst was reduced and the specific surface area was increased, and the excessive condensation reaction was suppressed.
Effective control of the molecular weight of condensation products improves the thermal stability and activity of the catalyst, promotes the synthesis of biomass fuel precursors, and solves the problems of low catalyst activity and easy deactivation.
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Figure CN122141736A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysis technology, and in particular to a solid base catalyst for regulating the aldol condensation process of biomass derivatives, its preparation method, and its application. Background Technology
[0002] Biomass is the only renewable organic carbon source in nature, and it has significant advantages in producing renewable fuels or high-value-added fine chemicals. This is especially true for the production of aviation fuel components via the aldol condensation-hydrodeoxygenation route.
[0003] Aldol condensation refers to the nucleophilic addition of compounds containing active α-hydrogen atoms, such as aldehydes, ketones, carboxylic acids, and esters, to carbonyl compounds under the action of acids or bases to yield α-hydroxy aldehydes, ketones, or acids, or further dehydration to yield α,β-unsaturated aldehydes, ketones, or acid esters. Biomass platforms first produce oxygen-containing compounds with suitable carbon chain lengths and structures through aldol condensation, which can then be hydrogenated and deoxygenated to convert into suitable alkanes for use as aviation fuel additives.
[0004] The aldol condensation reaction is generally catalyzed by homogeneous catalysts, especially NaOH solution. For environmental reasons, using solid bases as aldol condensation catalysts is essential. Furthermore, solid bases offer higher selectivity for cross-condensation products.
[0005] The condensation reaction of furfural and 2,5-hexanedione is a promising method for synthesizing branched-chain alkane precursors for aviation fuel. However, 2,5-hexanedione possesses two ketone groups, indicating high reactivity and a tendency to generate high-molecular-weight condensation products during its reaction with furfural. Experimental studies have also demonstrated that even weakly basic solid base catalysts can lead to excessive condensation. Therefore, there is an urgent need to provide a solid base catalyst to address the problem of low catalyst activity and easy deactivation caused by the large molecular weight of condensation products in the hydrodeoxygenation process for aviation fuel. Summary of the Invention
[0006] The purpose of this invention is to provide a solid base catalyst and its preparation method for regulating the aldol condensation process of biomass derivatives, and its application, in order to solve the technical problem that some aldol condensation reactions in the prior art are prone to producing high molecular weight condensation products.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] A method for preparing a solid base catalyst for regulating the aldol condensation process of biomass derivatives includes the following steps:
[0009] Magnesium nitrate hexahydrate and aluminum nitrate nonahydrate solutions were dissolved in deionized water to obtain solution A. Solution A was added dropwise to sodium carbonate solution and subjected to ultrasonic treatment. NaOH solution was then added dropwise to the solution to obtain solution B. Solution B was heated and stirred, filtered to collect the precipitate, washed and dried to obtain Mg-Al hydrotalcite precursor. The Mg-Al hydrotalcite precursor was calcined in a muffle furnace to obtain Mg-Al hydrotalcite. The Mg-Al hydrotalcite was thoroughly mixed with NaY molecular sieve and calcined again in a muffle furnace to obtain Mg-Al-HT / NaY solid base catalyst.
[0010] Furthermore, the method includes the following steps:
[0011] (1) Dissolve a certain proportion of magnesium nitrate hexahydrate solution and aluminum nitrate nonahydrate solution in deionized water to obtain solution A;
[0012] (2) Add solution A dropwise to sodium carbonate solution and sonicate it. Then add NaOH solution to the solution to adjust the pH to 10-11 to obtain solution B.
[0013] (3) At a certain temperature, solution B precipitates at a speed of 500 r / min. The precipitate is collected by filtration, washed with deionized water multiple times and dried to obtain Mg-Al hydrotalcite precursor.
[0014] (4) The prepared hydrotalcite precursor was placed in a muffle furnace and calcined to obtain Mg-Al hydrotalcite;
[0015] (5) The hydrotalcite and NaY molecular sieve are thoroughly mixed in proportion and then calcined in a muffle furnace to obtain the Mg-Al-HT / NaY catalyst.
[0016] Furthermore, in step (1), the molar ratio of magnesium nitrate hexahydrate and aluminum nitrate nonahydrate is (1~3):1 (Mg:Al=(1~3):1), and the concentration of magnesium nitrate and aluminum nitrate in the resulting solution A is 1 mol / L.
[0017] Furthermore, in step (2), the concentration of the sodium carbonate solution is 0.2 mol / L, the concentration of the NaOH solution is 1.6 mol / L, and the volume ratio of solution A to sodium carbonate solution is 3:2.
[0018] Furthermore, in step (3), the heating temperature during the stirring process of solution B is 60°C, and the drying condition is drying at 100°C for 24 hours.
[0019] Furthermore, in step (4), the calcination temperature is 450℃, the calcination time is 7h, and the heating rate is 5℃ / min.
[0020] Furthermore, in step (5), the mass ratio of hydrotalcite and NaY molecular sieve is (1~4):1. The mixing method is to grind them together in the same mortar, the calcination temperature is 500℃, the calcination time is 4h, and the heating rate is 5℃ / min.
[0021] This invention provides a method for preparing a solid alkali for regulating the aldol condensation process of biomass derivatives.
[0022] This invention provides the application of a solid base capable of controlling the molecular weight of aldol condensation products in the synthesis of biomass fuel precursors, comprising the following steps:
[0023] Furfural, ketone compounds, catalyst, and solvent were mixed and placed in a high-pressure stirred reactor. The temperature, reaction time, and rotation speed (500 rpm) were set, and the reaction was carried out. After the reaction was completed, the solid base catalyst was removed by centrifugation, and the condensation product solution was then placed in a micro-sample distillation apparatus to evaporate and remove the substrate and solvent.
[0024] Furthermore, the reaction temperature is 60~120℃, the reaction time is 8~12h, the solvent used is a water-isopropanol (volume ratio of 0.5-2) mixed solution, and the amounts of furfural, ketones, catalyst and solvent used are 0.2mol:0.1mol:1g:15m.
[0025] Beneficial effects
[0026] Mixing a strong solid alkali with a molecular sieve reduces the basicity of the solid alkali but increases the specific surface area of the catalyst. This lowers the molecular weight of the condensation product without sacrificing too much conversion rate in the condensation reaction. The solid alkali catalyst obtained by mixing hydrotalcite and NaY molecular sieve in this invention possesses high specific surface area, thermal stability, and high activity. It exhibits excellent performance in catalyzing the condensation reactions of furfural and various ketones. Furthermore, in the reaction of furfural and 2,5-hexanedione, it not only achieves a product yield of 51.3% but also successfully controls the molecular weight to 495, significantly lower than the condensation products obtained with NaOH solution and other solid alkali catalysts at the same temperature.
[0027] This catalyst exhibits excellent regulatory effects on the aldol condensation of aldehyde-ketone biomass derivatives such as furfural and 2,5-hexanedione, inhibiting addition polymerization and excessive condensation reactions, effectively controlling the molecular weight of the condensation products, and avoiding the formation of large molecular weight condensation products. The catalyst of this invention is used to regulate the synthesis of condensation products with carbon chain lengths suitable for aviation fuel components, which helps solve the problem of low catalyst activity and easy deactivation caused by large molecular weight condensation products in the hydrodeoxygenation process for aviation fuel. The catalyst prepared by this invention has a large specific surface area and good thermal stability, effectively inhibiting excessive condensation reactions while retaining a considerable amount of catalytic activity. Attached Figure Description
[0028] Figure 1 This is a molecular weight distribution diagram of the product obtained in Example 13.
[0029] Figure 2 CO2-TPD diagrams of Mg-Al(3:1)-HT / NaY solid alkalis with different ratios of hydrotalcite and molecular sieve. Detailed Implementation
[0030] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0031] The present invention aims to provide a method for preparing a solid base for regulating the aldol condensation process of biomass derivatives, thereby solving the technical problem that some aldol condensation reactions in the prior art easily produce high molecular weight condensation products. The method includes the following steps:
[0032] (1) Dissolve a certain proportion of magnesium nitrate hexahydrate solution and aluminum nitrate nonahydrate solution in deionized water to obtain solution A;
[0033] (2) Add solution A dropwise to sodium carbonate solution and sonicate it. Then add NaOH solution to the solution to adjust the pH to 10-11 to obtain solution B.
[0034] (3) At a certain temperature, solution B precipitates at a speed of 500 r / min. The precipitate is collected by filtration, washed with deionized water multiple times and dried to obtain Mg-Al hydrotalcite precursor.
[0035] (4) The prepared hydrotalcite precursor was placed in a muffle furnace and calcined to obtain Mg-Al hydrotalcite;
[0036] (5) The hydrotalcite and NaY molecular sieve are thoroughly mixed in proportion and then calcined in a muffle furnace to obtain the Mg-Al-HT / NaY catalyst.
[0037] In some embodiments, the molar ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is (1~3):1 (Mg:Al=(1~3):1), and the concentration of magnesium nitrate and aluminum nitrate in the resulting solution A is 1 mol / L. Preferably, the molar ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is 1:1, 2:1, or 3:1 (Mg:Al=1:1, 2:1, or 3:1).
[0038] In some embodiments, the concentration of the sodium carbonate solution is 0.2 mol / L, the concentration of the NaOH solution is 1.6 mol / L, and the volume ratio of solution A to sodium carbonate solution is 3:2.
[0039] In some embodiments, solution B is heated to 60°C during stirring and dried at 100°C for 24 hours.
[0040] In some embodiments, the calcination temperature is 450°C, the calcination time is 7 hours, and the heating rate is 5°C / min.
[0041] In some embodiments, the mass ratio of hydrotalcite to NaY molecular sieve is (1~4):1, and the mixing method is to grind them together in the same mortar, calcining at 500°C for 4 hours, and heating at a rate of 5°C / min. Preferably, the mass ratio of hydrotalcite to NaY molecular sieve is (1:1, 1:2, 1:3, and 1:4).
[0042] On the other hand, the present invention provides a method for preparing a solid base that can control the molecular weight of the aldol condensation product.
[0043] This invention provides the application of a solid base capable of controlling the molecular weight of aldol condensation products in the synthesis of biomass fuel precursors, comprising the following steps:
[0044] Furfural, ketone compounds, catalyst, and solvent were mixed and placed in a high-pressure stirred reactor. The temperature, reaction time, and rotation speed (500 rpm) were set, and the reaction was carried out. After the reaction was completed, the solid base catalyst was removed by centrifugation, and the condensation product solution was then placed in a micro-sample distillation apparatus to evaporate and remove the substrate and solvent.
[0045] Furthermore, the reaction temperature is 60~120℃, the reaction time is 8~12h, the solvent used is a water-isopropanol (volume ratio 0.5-2) mixed solution, and the amounts of furfural, ketones, catalyst, and solvent used are 0.2mol:0.1mol:1g:15m. Preferably, the reaction temperature is 60℃, 80℃, 100℃, or 120℃, the reaction time is 8h, 10h, or 12h, and the volume ratio of the water-ethanol mixed solvent used is 1:2, 1:1, or 2:1.
[0046] The present application will be further described in detail below with reference to specific embodiments and accompanying drawings. These embodiments should not be construed as limiting the scope of protection claimed in this application.
[0047] Examples 1-3
[0048] 1) Dissolve 1 mol / L magnesium nitrate solution and 1 mol / L aluminum nitrate solution in deionized water at volume ratios of 3:1, 2:1, and 1:1 to obtain 150 mL of solution A;
[0049] 2) Add solution A dropwise to 100 mL of 0.2 mol / L sodium carbonate solution and sonicate. Then add 1.6 mol / L NaOH solution to adjust the pH to 10-11 to obtain solution B.
[0050] 3) Heat solution B to 60°C. At 60°C, precipitate solution B at a rotation speed of 500 r / min. Collect the precipitate by filtration, wash it with deionized water several times and dry it to obtain the Mg-Al hydrotalcite precursor.
[0051] 4) The prepared hydrotalcite precursor was placed in a muffle furnace for calcination at 450℃ for 7 hours with a heating rate of 5℃ / min to obtain Mg-Al hydrotalcite.
[0052] Furfural, hexanedione, Mg-Al hydrotalcite, and solvent were mixed and reacted to obtain the condensation product. The reaction temperature was 100℃, the reaction time was 10 h, and the solvent used was a water-isopropanol (volume ratio 1:1) mixture. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. After the reaction, the solid base catalyst was removed by centrifugation, and the solvent and substrate were evaporated to obtain the condensation product. The concentrated condensation product was dissolved in THF, and the average molecular weight was determined by GPC. 0.1 mL of the reaction solution was diluted with methanol, and the conversion rates of furfural and hexanedione were determined by gas chromatography. The specific results are shown in Table 1.
[0053] Examples 4-7
[0054] The hydrotalcite Mg-Al(3:1)-HT obtained in Example 1 was ground and thoroughly mixed with NaY molecular sieve in mass ratios of 1:4, 1:3, 1:2, and 1:1. The mixture was then placed in a muffle furnace for calcination at a temperature of 500°C for 4 hours at a heating rate of 5°C / min. The resulting catalyst was denoted as Mg-Al-HT / xNaY, where x is the mass ratio of NaY to Mg-Al-HT(3:1).
[0055] Furfural and hexanedione, along with the aforementioned catalyst and solvent, were mixed and reacted to obtain the condensation product. The reaction temperature was 100℃, and the reaction time was 10 h. The solvent used was a water-isopropanol (volume ratio 1:1) mixture. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods are described in Examples 1-3. Specific results are shown in Table 1.
[0056] Table 1. Catalysts used in Examples 1-7 and reaction results
[0057]
[0058] The above results indicate that although the catalyst yield and conversion are highest when Mg:Al = 3:1, the average molecular weight of the product is significantly increased. This is because MgO is the main provider of basic sites, and increasing the MgO content inevitably enhances the catalyst's activity for aldol condensation. After adding molecular sieves, although the catalytic effect of the resulting catalyst decreases in both conversion and yield, the average molecular weight of the final product is also significantly reduced. This is because mixing NaY molecular sieves inevitably reduces the number of active sites on the catalyst surface.
[0059] Comparative Example 1
[0060] 1.92 g of furfural and 1.14 g of 2,5-hexanedione were each mixed with 10 mL of deionized water. These mixtures were then combined with 10 mL of 0.5 M NaOH solution under vigorous stirring and reacted at 40 °C for 2 h. After the reaction was complete, the total mass of the reaction system was measured. The solvent was evaporated, and the mass of NaOH and the weight of the reactor were subtracted to obtain the mass of the condensation product. A portion of the washed condensation product was dissolved in THF solution, and the average molecular weight was determined using GPC. The results are shown in Table 2.
[0061] The results of Comparative Example 1 show that although the homogeneous NaOH solution has the highest reaction yield and conversion rate when used as a catalyst, it is completely impossible to control the excessive condensation reaction.
[0062] Comparative Examples 2-3
[0063] Furfural and 2,5-hexanedione, along with a mixture of CaO or MgO and water-isopropanol (1:1), were mixed at a ratio of 0.2 mol: 0.1 mol: 1 g: 15 mL and reacted at a specific temperature for 10 h. After the reaction, the solid base catalyst was removed by centrifugation, and the solvent and substrate were evaporated to obtain the condensation product. The concentrated condensation product was dissolved in THF, and the average molecular weight was determined using GPC. 0.1 mL of the reaction solution was diluted with methanol, and the conversion rates of furfural and hexanedione were determined by gas chromatography. The results are shown in Table 2.
[0064] Comparative Examples 2 and 3 are two commercial solid bases: CaO, a strong base, and MgO, a weak base. Although the strong base CaO can achieve higher yields and conversion rates, it cannot effectively control the excessive condensation reaction, and the average molecular weight of the product reaches 876. The weak base MgO makes it difficult for the condensation reaction to proceed fully, and the yield is only 21.3%.
[0065] Comparative Example 4
[0066] By simply replacing the magnesium nitrate hexahydrate used in Example 1 with the same amount of cobalt chloride hexahydrate, while keeping all other conditions unchanged, Co-Al(3:1)-HT can be obtained.
[0067] Furfural and 2,5-hexanedione, a mixed solvent of Co-Al(3:1)-HT and water-isopropanol(1:1) was mixed at a ratio of 0.2 mol: 0.1 mol: 1 g: 15 mL and reacted at a certain temperature for 10 h. After the reaction, the solid base catalyst was removed by centrifugation, and the solvent and substrate were evaporated to obtain the condensation product. The concentrated condensation product was dissolved in THF, and the average molecular weight was determined by GPC. 0.1 mL of the reaction solution was diluted with methanol, and the conversion rates of furfural and hexanedione were determined by gas chromatography. The results are shown in Table 2.
[0068] In Comparative Example 4, the highly alkaline MgO in the hydrotalcite was replaced with CoO, which weakened the alkalinity of the catalyst surface, preventing the condensation reaction from proceeding fully.
[0069] Compared to Comparative Examples 1-4, Example 7 can enhance the catalytic effect on the condensation reaction by utilizing the high alkalinity of Mg-Al hydrotalcite, and introduce NaY to increase the overall specific surface area and reduce the alkalinity. While effectively reducing the average molecular weight, it retains a mass yield of 51.3%.
[0070] Table 2 Catalysts and reaction results for Comparative Examples 1-4
[0071]
[0072] Comparative Examples 5-7
[0073] Take the four solid base catalysts used in Comparative Examples 2 to 4, grind and mix them thoroughly with NaY type molecular sieve at a mass ratio of 1:1, and then calcine them in a muffle furnace at a temperature of 500℃ for 4 hours with a heating rate of 5℃ / min.
[0074] Furfural and hexanedione, along with the aforementioned catalyst and solvent, were mixed and reacted to obtain the condensation product. The reaction temperature was 100℃, and the reaction time was 10 h. The solvent used was a water-isopropanol (volume ratio 1:1) mixture. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods are described in Examples 1-3. Specific results are shown in Table 3.
[0075] Table 3. Reaction effects of new solid base catalysts obtained by mixing different solid bases with NaY molecular sieves
[0076]
[0077] The above results indicate that Mg-Al-HT has the best effect because Mg-Al-HT is more basic than Co-Al-HT and MgO, and has some acidic sites. The acid-base synergistic catalytic effect is better than CaO, which only has basic sites.
[0078] Examples 8-10
[0079] Furfural and hexanedione, the catalyst obtained in Example 7, and the solvent were mixed and reacted to obtain the condensation product. The reaction temperature was 60-120℃, the reaction time was 10 h, and the solvent used was a water-isopropanol (volume ratio 1:1) mixed solution. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods are as described in Examples 1-3. Specific results are shown in Table 4.
[0080] Table 4. Reaction effect of Mg-Al-HT / NaY solid base catalyst at different temperatures
[0081]
[0082] The above results indicate that the condensation reaction is most effective at a temperature of 100℃. This is because the reaction is insufficient at too low a temperature, while excessively high temperatures will promote the condensation reaction to proceed excessively.
[0083] Examples 11-12
[0084] Furfural and hexanedione, the catalyst obtained in Example 7, and the solvent were mixed and reacted to obtain the condensation product. The reaction temperature was 100°C, and the reaction time was 8 and 12 hours. The solvent used was a water-isopropanol (volume ratio 1:1) mixed solution. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods are described in Examples 1-3. Specific results are shown in Table 5.
[0085] Table 5. Reaction effect of Mg-Al-HT / NaY solid base catalyst at different reaction times.
[0086]
[0087] The above results indicate that the condensation reaction time is 10 hours, which is the best time. This is because the reaction is not complete in a shorter reaction time, while a longer reaction time will promote excessive condensation reaction.
[0088] Examples 13-14
[0089] Furfural and hexanedione, the catalyst obtained in Example 7, and the solvent were mixed and reacted to obtain the condensation product. The reaction temperature was 100°C, the reaction time was 10 h, and the solvent used was a water-isopropanol mixed solution with a volume ratio of 2:1 and 1:2. The amounts of furfural, hexanedione, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods are as described in Examples 1-3. Specific results are shown in Table 6.
[0090] Table 6. Reaction effect of Mg-Al-HT / NaY solid base catalyst under different solvent ratios
[0091]
[0092] The above results indicate that the best effect is achieved when the solvent ratio is 1:1. This is because, at high temperatures, solid bases are soluble in water but completely insoluble in isopropanol. Increasing the water ratio allows for more complete contact between the substrate and the catalyst, thereby increasing the yield of the condensation reaction. However, it also promotes excessive condensation. Increasing the alcohol ratio is not conducive to the reaction and reduces the yield.
[0093] Examples 15-18
[0094] The Mg-Al-HT / 1NaY prepared in Example 7 was used for the condensation reaction of furfural with different ketones. These different ketones refer to acetone, 2-butanone, 2-hexanone, and levulinic acid, all of which are common platform molecules in biomass. The reaction temperature was 100℃, the reaction time was 10 h, and the solvent used was a water-isopropanol (volume ratio 1:1) mixture. The amounts of furfural, ketone compounds, catalyst, and solvent used were 0.2 mol: 0.1 mol: 1 g: 15 mL. The test methods were the same as in Examples 1-3, and the specific results are shown in Table 7.
[0095] Table 7. Effects of Mg-Al-HT / 1NaY on the condensation reaction of furfural with different ketones.
[0096]
[0097] The above results indicate that the reaction using furfural and hexanedione yields the best results, achieving a product yield of 51.3% and successfully controlling the molecular weight at 495, which is significantly lower than the condensation products obtained with NaOH solution and other solid base catalysts at the same temperature.
[0098] As illustrated by the above examples, this invention provides a method for preparing and applying a solid base for regulating the aldol condensation process of biomass derivatives. This invention first synthesizes Mg-Al hydrotalcite using a conventional co-precipitation method, then mixes the hydrotalcite with NaY molecular sieves to obtain a Mg-Al-HT / NaY solid base catalyst. The catalyst prepared by this invention can be used for the catalytic synthesis of biomass fuels. The catalyst prepared by this invention has a high specific surface area and thermal stability; it has low preparation cost and high catalytic activity, effectively catalyzing the aldol condensation reaction of low-activity substrates. The catalyst prepared by this invention not only exhibits high activity and a certain ability to regulate molecular weight in the condensation reaction of furfural and hexanedione, but also shows high activity in condensation reactions using other ketones as substrates.
[0099] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a solid base catalyst for regulating the aldol condensation process of biomass derivatives, characterized in that, Includes the following steps: Dissolve magnesium nitrate hexahydrate solution and aluminum nitrate nonahydrate solution in deionized water to obtain solution A; Solution A was added dropwise to sodium carbonate solution and sonicated. Then, NaOH solution was added dropwise to the solution to obtain solution B. Solution B was heated and stirred, the precipitate was collected by filtration, washed and dried to obtain Mg-Al hydrotalcite precursor; the Mg-Al hydrotalcite precursor was placed in a muffle furnace for calcination to obtain Mg-Al hydrotalcite; the Mg-Al hydrotalcite was thoroughly mixed with NaY molecular sieve and placed in a muffle furnace for calcination again to obtain a solid base catalyst for regulating the aldol condensation process of biomass derivatives.
2. The preparation method according to claim 1, characterized in that, The molar ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is 1~3:1, and the concentration of magnesium nitrate in the resulting solution A is 0.5~1.5 mol / L.
3. The preparation method according to claim 1, characterized in that, The concentration of sodium carbonate solution is 0.1~0.3 mol / L, the concentration of NaOH solution is 1~2 mol / L, and the volume ratio of solution A to sodium carbonate solution is 3:
2.
4. The preparation method according to claim 1, characterized in that, The temperature of solution B during stirring is 60℃, the drying temperature is 100℃, and the drying time is 24h.
5. The preparation method according to claim 1, characterized in that, The calcination temperature of the Mg-Al hydrotalcite precursor is 400~500℃, the calcination time is 6~8h, and the heating rate is 4~6℃ / min.
6. The preparation method according to claim 1, characterized in that, The mass ratio of Mg-Al hydrotalcite to NaY molecular sieve is 1:1~4. The mixing method is to grind them together in the same mortar. The calcination temperature is 450~550℃, the calcination time is 3~5h, and the heating rate is 4~6℃ / min.
7. A solid base catalyst for regulating the aldol condensation process of biomass derivatives, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.
8. The application of the solid base catalyst of claim 7 for regulating the aldol condensation process of biomass derivatives in the aldol condensation reaction.
9. The application according to claim 8, characterized in that, The solid base catalyst used to regulate the aldol condensation process of biomass derivatives is used to regulate the aldol condensation process and the molecular weight of the condensation product. The aldol condensation reaction includes the following steps: Furfural, ketone compounds, the solid base catalyst as described in claim 8, and solvent are mixed and placed in a high-pressure stirred reactor for reaction. After the reaction is completed, the solid base catalyst is removed by centrifugation, and the condensation product solution is placed in a micro sample distillation apparatus to evaporate and remove the substrate and solvent.
10. The application according to claim 9, characterized in that, The reaction temperature is 60~120℃, the reaction time is 8~12h, the solvent used is a water-isopropanol mixed solution, the volume ratio of water to isopropanol is 0.5~2:1; the amounts of furfural, ketones, solid base catalyst and solvent are 0.2mol:0.1mol:1g:10~15mL.