Preparation of isosorbide catalyst, method for preparing the same and use thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-10-20
- Publication Date
- 2026-05-29
AI Technical Summary
Existing catalysts for the preparation of isosorbide suffer from problems of separation difficulties and low selectivity. In particular, homogeneous catalysts are difficult to produce on a large scale and continuously, while heterogeneous catalysts have low selectivity for isosorbide.
An organic/inorganic hybrid material is used as a catalyst, in which functional groups containing two or more nitrogen atoms and hydrophobic groups without nitrogen are combined with mesoporous silica material. After haloalkylation and hydrophobization treatment, it reacts with compounds containing two or more nitrogen atoms to form a heterogeneous catalyst.
It achieves easy separation and high selectivity of catalyst, with sorbitol conversion ≥92% and isosorbitol selectivity ≥90%, making it suitable for large-scale continuous production.
Smart Images
Figure CN117917282B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a catalyst for the preparation of isosorbide, its preparation method, and its application. Background Technology
[0002] Isosorbide (1,4:3,6-didehydro-D-glucol) is considered an important bio-based raw material second only to lactic acid and is currently the only sugar alcohol monomer that has been industrially produced. The industrial production of isosorbide mainly employs a three-step process: (1) starch (or cellulose) is hydrolyzed into glucose; (2) glucose is catalytically hydrogenated to obtain sorbitol; and (3) sorbitol is dehydrated twice to obtain isosorbide. The third step primarily uses sulfuric acid as a catalyst. Under vacuum and at a reaction temperature of 127°C, the reaction time is 1–5 hours, and the yield of isosorbide is 70%–77%. Although using liquid acid as a catalyst has high catalytic efficiency, the complex separation process, the non-recyclable nature of the catalyst, and the stringent requirements for reaction equipment result in poor atom economy and an unfriendly environment for this production process. Therefore, attention has been turned to solid acid catalysis, and various solid acid catalysts have been developed, such as acidic ion exchange resins, sulfonated mesoporous materials, acidic zeolites, supported metal salts, metal phosphates, sulfated and phosphorylated metal oxides, and supported heteropoly acids. However, the yield of isosorbide obtained using the above-mentioned solid acid catalysis still needs to be further improved, and the reaction conditions are harsh (high temperature, vacuum, or microwave assistance, or a reducing atmosphere is required).
[0003] The efficient route to isosorbide production involves reacting sorbitol and dimethyl carbonate with alkaline catalysts such as K₂CO₃, sodium methoxide, triethylenediamine (DABCO), 1,8-diazobispirocyclo(5.4.0)undec-7-ene (DBU), or 157-triazidobicyclo(4.4.0)dec-5-ene (TBD). In particular, using DBU as a catalyst, both the sorbitol conversion and isosorbide selectivity are 100%, and the isosorbide yield reaches as high as 98% after separation and purification. However, these catalysts are homogeneous and require large quantities, leading to difficulties in separation, significant waste emissions, and limitations in large-scale continuous production. Therefore, attention has turned to heterogeneous catalysts, but existing heterogeneous catalysts exhibit low isosorbide selectivity, such as the porous alkaline supported ionic liquid catalyst disclosed in CN108126749B. Developing a catalyst that combines easy separation and high selectivity for the reaction of p-sorbitol and dimethyl carbonate to prepare isosorbide is crucial. Summary of the Invention
[0004] In view of the existing catalysts for the preparation of isosorbide, which are difficult to separate and have low selectivity, this invention provides a catalyst for the preparation of isosorbide, its preparation method and application. This catalyst can efficiently catalyze the reaction of sorbitol and dimethyl carbonate to prepare isosorbide, and has the characteristics of easy separation and high selectivity.
[0005] The first aspect of the present invention provides a catalyst for preparing isosorbide, wherein the catalyst is an organic / inorganic hybrid material, wherein the organic component includes functional groups containing two or more nitrogen atoms and hydrophobic groups that do not contain nitrogen, and the inorganic component is a mesoporous silica material.
[0006] In the above technical solution, the functional group containing two or more N atoms is obtained by reacting a compound containing two or more N atoms with a haloalkyl group.
[0007] In the above technical solution, preferably, the compound containing two or more N atoms can be at least one of 1,8-diazobispirocyclo(5.4.0)undec-7-ene (DBU), 1,5,7-triazidobicyclo(4.4.0)dec-5-ene (TBD), triethylenediamine (DABCO), imidazole, imidazoline, pyrazole, and piperazine.
[0008] In the above technical solution, preferably, the haloalkyl group can be at least one of chloromethyl, chloropropyl, bromopropyl, and iodopropyl.
[0009] In the above technical solution, preferably, the nitrogen-free hydrophobic group can be at least one of methyl, dimethyl, trimethyl, ethyl, and propyl.
[0010] In the above technical solution, preferably, the molar ratio of functional groups containing two or more N atoms and hydrophobic groups that do not contain nitrogen is 0.5 to 7.
[0011] A second aspect of this invention provides a method for preparing an isosorbide catalyst, comprising the following steps:
[0012] (1) Synthesis of mesoporous silica materials;
[0013] (2) Disperse the mesoporous silica material obtained in step (1) into solvent I, and under an inert atmosphere, reflux for the first time, add haloalkylating agent and hydrophobicating agent, and reflux for the second time to obtain pore haloalkylated and hydrophobic mesoporous silica material.
[0014] (3) The mesoporous silica material with halogenated and hydrophobic pores obtained in step (2) is dispersed in solvent II, and a compound containing two or more N atoms in the molecule is added under an inert atmosphere to react and obtain the catalyst.
[0015] In the above technical solution, preferably, the mesoporous silica material in step (1) is a mesoporous silica material with disordered or ordered pores; more preferably, the mesoporous silica material in step (1) is selected from at least one of SBA-15, MCM-41, MCM-48, KIT-6, FDU-5, AMS-10, HMS, MSU, KIT-1 and TUD-1.
[0016] In the above technical solution, the mesoporous silica material can be prepared according to conventional methods in the art. There are no particular limitations on the pore size and specific surface area of the mesoporous silica material. Preferably, in the embodiments of the present invention, the pore size of the mesoporous silica material is 2–15 nm, and the specific surface area is 300–1500 m². 2 / g.
[0017] In the above technical solution, preferably, the solvent I in step (2) is selected from at least one of toluene, n-hexane, and cyclohexane. The volume of the solvent I is 5-500 mL / g based on the mass of the mesoporous silica material. Those skilled in the art can select a suitable desiccant to dry the solvent I first, depending on the solvent.
[0018] In the above technical solution, preferably, the inert gas in step (2) is selected from at least one of nitrogen and helium.
[0019] In the above technical solution, preferably, the haloalkylating agent in step (2) is selected from at least one of chloromethyltrimethoxysilane, chloropropyltrimethoxysilane, bromopropyltrimethoxysilane, and iodopropyltrimethoxysilane.
[0020] In the above technical solution, preferably, the hydrophobic reagent in step (2) is selected from at least one of methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, hexamethyldisilazane, and trimethylchlorosilane.
[0021] In the above technical solution, preferably, the molar ratio of the haloalkylating agent and the hydrophobicating agent in step (2) is 0.5 to 7.
[0022] In the above technical solution, preferably, the mass ratio of the mesoporous silica material to the haloalkylating reagent in step (2) is 1 to 10.
[0023] In the above technical solution, preferably, the time for the first reflux in step (2) is ≥0.2h, preferably 0.5~2h; and the time for the second reflux is ≥1h, preferably 4~72h.
[0024] In the above technical solution, preferably, after the reaction in step (2) is completed, the material is subjected to conventional filtration, washing, and drying to obtain a mesoporous silica material with halogenated and hydrophobic channels. The washing can be performed using solvent I to remove unreacted silane coupling agent. The drying can be carried out in any manner conventionally known in the art, wherein the drying temperature does not exceed 120°C.
[0025] In the above technical solution, preferably, the compound containing two or more N atoms in step (3) is selected from at least one of DBU, TBD, DABCO, imidazole, imidazoline, pyrazole, piperazine and its derivatives.
[0026] In the above technical solution, preferably, solvent II in step (3) is 1,4-dioxane. The volume of solvent II is 5 to 500 mL / g, calculated based on the mass of a compound containing two or more N atoms in its molecule.
[0027] In the above technical solution, preferably, the mass ratio of the compound containing two or more N atoms in the molecule in step (3) to the mass ratio of the pore-halogenated and hydrophobic mesoporous silica material is 0.1 to 1.2.
[0028] In the above technical solution, preferably, the reaction conditions in step (3) are as follows: the reaction temperature is 25~101℃, preferably 60~101℃, and the reaction time is ≥6h, preferably 6~72h.
[0029] In the above technical solution, after the reaction in step (3) is completed, the catalyst is obtained through conventional filtration, washing, and drying. The washing can be performed using 1,4-dioxane and methanol to remove unreacted organic amines. The drying can be carried out in any manner conventionally known in the art, wherein the drying temperature does not exceed 120°C.
[0030] The third aspect of the present invention provides the application of the above-described catalyst or the catalyst prepared by the above-described preparation method in the reaction for the preparation of isosorbide.
[0031] The specific application is as follows: isosorbide is prepared from sorbitol and dimethyl carbonate under the action of the above catalyst.
[0032] In the above technical solution, the molar ratio of dimethyl carbonate to sorbitol is 2 to 50, and the amount of catalyst used is 10% to 50% of the mass of sorbitol.
[0033] In the above technical solution, the reaction temperature is 80-200℃ and the reaction time is 4-72h.
[0034] Compared with the prior art, the present invention has the following beneficial effects:
[0035] (1) The present invention provides a catalyst for the preparation of isosorbide, which is an organic / inorganic hybrid heterogeneous catalyst. The modification of the silanizing agent gives it unique hydrophilicity and hydrophobicity, while the introduction of a compound containing two or more N atoms gives it unique basicity. This solves the problems of separation difficulties and low product selectivity in the catalysts for the preparation of isosorbide in the prior art.
[0036] (2) In this invention, mesoporous silica material is first subjected to haloalkylation and hydrophobication treatment, and then a compound containing two or more nitrogen atoms in its molecule is added for reaction, ultimately yielding an isosorbide catalyst with unique hydrophilicity, hydrophobicity, and basicity. The method provided by this invention is simple and feasible. Using the catalyst of this invention, the sorbitol conversion rate is ≥92%, and the isosorbide selectivity is ≥90%. Attached Figure Description
[0037] Figure 1 This is a TEM image of the catalyst prepared in Example 3. Detailed Implementation
[0038] To more clearly illustrate the technical solution of the present invention, the following specific embodiments are listed. However, those skilled in the art will readily understand that the description of the embodiments is for illustrative purposes only and should not, and will not, limit the invention as described in detail in the claims.
[0039] In this invention, transmission electron microscopy (TEM) was used to observe the mesoporous properties of the catalyst. The TEM used was a Tecnai 20 S-TWIN, operating at 200 kV.
[0040] In this invention, elemental analysis was used to determine the C and N content in the catalyst. The elemental analyzer used was a FLASH 2000 CHNS-O ANALYZER.
[0041]
Example 1
[0042] (1) At 38℃, 4g of surfactant P123 was dissolved in 130ml of H2O and 21ml of concentrated hydrochloric acid, and the mixture was stirred until the solution was homogeneous. 9.8g of tetraethyl orthosilicate (TEOS) was added and the mixture was stirred for 20 hours. The mixture was placed in a constant temperature oven at 100℃ for 24 hours to crystallize. After cooling to room temperature, the mixture was filtered and washed several times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material SBA-15.
[0043] (2) Weigh 2.0 g of the above SBA-15 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 0.6 mL of chloropropyltrimethoxysilane (M = 198.72 g / mol, e = 1.09 g / cm³). 3 ) and 0.4 mL of propyltrimethoxysilane (M = 164.27 g / mol, e = 0.932 g / cm) 3 The mixture was refluxed in a nitrogen atmosphere for 16 hours, filtered, thoroughly washed with toluene, and dried to obtain chloroalkylated and hydrophobic mesoporous silica material SBA-15.
[0044] (3) The chloroalkylated and hydrophobic mesoporous silica material SBA-15 obtained above was added to 25 mL of 1,4-dioxane containing 0.567 g piperazine (6.58 mmol, 2 equivalents, M = 86.14 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst A.
[0045]
Example 2
[0046] (1) At room temperature (25℃), 0.8g CTAB was dissolved in 38g H2O and 4.0g (2mol / L) NaOH solution, and the mixture was stirred until homogeneous. 3.8g tetraethyl orthosilicate (TEOS) was added, and the mixture was stirred for 1 hour. The mixture was then placed in a constant temperature oven at 100℃ for 72 hours for crystallization treatment. After cooling to room temperature, the mixture was filtered and washed multiple times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material MCM-41.
[0047] (2) Weigh 2.0 g of the above MCM-41 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 0.7 mL of chloromethyltrimethoxysilane (M = 170.67 g / mol, e = 1.132 g / cm³). 3 ) and 0.3 mL of dimethyldimethoxysilane (M = 120.22 g / mol, e = 0.88 g / cm) 3 The mixture was refluxed in a nitrogen atmosphere for 16 hours, filtered, thoroughly washed with toluene, and dried to obtain chloroalkylated and hydrophobic mesoporous silica material MCM-41.
[0048] (3) The chloroalkylated and hydrophobic mesoporous silica material MCM-41 obtained above was added to 25 mL of 1,4-dioxane containing 0.65 g of 2-imidazoline (9.28 mmol, 2 equivalents, M = 70.09 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst B.
[0049]
Example 3
[0050] (1) At 35℃, 6.0g of P123 was dissolved in 217g of H2O and 11.8g of (12mol / L) HCl solution, and the mixture was stirred until the solution was homogeneous. 6.0g of n-butanol was added and the mixture was stirred for 1h. 12.9g of tetraethyl orthosilicate (TEOS) was added and the mixture was stirred for 24h. The mixture was then placed in a constant temperature oven at 100℃ for 24h to stand and crystallize. After cooling to room temperature, the mixture was filtered and washed multiple times with deionized water. After drying, it was calcined at 550℃ for 6h to obtain mesoporous silica material KIT-6.
[0051] (2) Weigh 2.0 g of the above KIT-6 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 0.8 mL of bromopropyltrimethoxysilane (M = 243.17 g / mol, e = 1.298 g / cm³). 3 ) and 0.2 mL of ethyltrimethoxysilane (M = 150.25 g / mol, e = 0.94 g / cm) 3 ) Continue reflux in a nitrogen atmosphere for 16 hours, filter, wash thoroughly with toluene, and dry to obtain brominated and hydrophobic mesoporous silica material KIT-6;
[0052] (3) The above-obtained bromoalkylated and hydrophobic mesoporous silica material KIT-6 was added to 25 mL of 1,4-dioxane containing 1.189 g TBD (8.54 mmol, 2 equivalents, M = 139.2 g / mol), reacted at 100 °C for 24 h, filtered, thoroughly washed with 1,4-dioxane and methanol, and dried to obtain catalyst C.
[0053]
Example 4
[0054] (1) At room temperature (25℃), 0.8g CTAB was dissolved in 38g H2O and 6g (2mol / L) NaOH solution and stirred until the solution was homogeneous. Then 3.8g tetraethyl orthosilicate (TEOS) was added and stirred for 1 hour. The solution was placed in a constant temperature oven at 110℃ for 72 hours for crystallization treatment. After cooling to room temperature, the solution was filtered and washed multiple times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material MCM-48.
[0055] (2) Weigh 2.0 g of the above MCM-48 and place it in 10 mL of dry n-hexane. Reflux under a nitrogen atmosphere for 1 h. Add 0.4 mL of iodopropyltrimethoxysilane (M = 290.17 g / mol, e = 1.482 g / cm³). 3 ) and 0.4 mL of methyltrimethoxysilane (M = 136.22 g / mol, e = 0.955 g / cm) 3The mixture was refluxed under a nitrogen atmosphere for 8 hours, filtered, thoroughly washed with n-hexane, and dried to obtain iodinated and hydrophobic mesoporous silica material MCM-48.
[0056] (3) The iodinated and hydrophobic mesoporous silica material MCM-48 obtained above was added to 135 mL of 1,4-dioxane containing 0.2783 g imidazole (4.088 mmol, 2 equivalents, M = 68.08 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst D.
[0057]
Example 5
[0058] (1) At room temperature (25℃), 1.0g P123, 15g ethanol, 0.1g (2mol / L) HCl solution and 0.9g H2O were stirred evenly, 2.08g tetraethyl orthosilicate (TEOS) was added, and the mixture was stirred for 2 hours. The mixture was then transferred to an open petri dish and allowed to stand for 48 hours. After that, it was placed in a reaction vessel and 50mL of n-hexane was added. The mixture was then solvothermal treated at 80℃ for 72 hours. After cooling to room temperature, the mixture was filtered and washed several times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material FDU-5.
[0059] (2) Weigh 2.0 g of the above FDU-5 and place it in 1000 mL of dry cyclohexane. Reflux under a nitrogen atmosphere for 1 h. Add 1.3 mL of chloromethyltrimethoxysilane (M = 170.67 g / mol, e = 1.132 g / cm³). 3 ) and 0.2 mL of methyltrimethoxysilane (M = 136.22 g / mol, e = 0.955 g / cm) 3 ) Continue reflux in a nitrogen atmosphere for 72 hours, filter, wash thoroughly with cyclohexane, and dry to obtain chloroalkylated and hydrophobic mesoporous silica material FDU-5;
[0060] (3) The chloroalkylated and hydrophobic mesoporous silica material FDU-5 obtained above was added to 15 mL of 1,4-dioxane containing 2.625 g DBU (17.24 mmol, 2 equivalents, M = 152.24 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst E.
[0061]
Example 6
[0062] (1) At room temperature (25℃), 2.54g of tetradecylamine was dissolved in 18.4g of anhydrous ethanol, and 130g of H2O was added and stirred to form an emulsion. Under vigorous stirring, 10.4g of tetraethyl orthosilicate (TEOS) was added dropwise over 15 minutes. Stirring was continued for 24 hours. The mixture was filtered and washed multiple times with deionized water. After drying, it was calcined at 600℃ for 6 hours to obtain mesoporous silica material HMS.
[0063] (2) Weigh 2.0 g of the above HMS and place it in 500 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 0.18 mL of chloromethyltrimethoxysilane (M = 170.67 g / mol, e = 1.132 g / cm³). 3 ) and 0.18 mL of ethyltrimethoxysilane (M = 150.25 g / mol, e = 0.94 g / cm) 3 The mixture was refluxed in a nitrogen atmosphere for 8 hours, filtered, thoroughly washed with toluene, and dried to obtain chloroalkylated and hydrophobic mesoporous silica material HMS.
[0064] (3) The chloroalkylated and hydrophobic mesoporous silica material HMS obtained above was added to 67 mL of 1,4-dioxane containing 0.2682 g DABCO (2.394 mmol, 2 equivalents, M = 112.17 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst F.
[0065] Comparative Example 1
[0066] The method is the same as in Example 1, except that propyltrimethoxysilane is not used, and it is replaced by an equal volume of chloropropyltrimethoxysilane. The corresponding amount of piperazine is increased, as detailed below:
[0067] (1) At 38℃, 4g of surfactant P123 was dissolved in 130ml of H2O and 21ml of concentrated hydrochloric acid, and the mixture was stirred until the solution was homogeneous. 9.8g of tetraethyl orthosilicate (TEOS) was added and the mixture was stirred for 20 hours. The mixture was placed in a constant temperature oven at 100℃ for 24 hours to crystallize. After cooling to room temperature, the mixture was filtered and washed multiple times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material SBA-15.
[0068] (2) Weigh 2.0 g of the above SBA-15 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 1 mL of chloropropyltrimethoxysilane (M = 198.72 g / mol, e = 1.09 g / cm³). 3 The mixture was refluxed in a nitrogen atmosphere for 16 hours, filtered, thoroughly washed with toluene, and dried to obtain chloroalkylated mesoporous silica material SBA-15.
[0069] (3) The chloroalkylated and hydrophobic mesoporous silica material SBA-15 obtained above was added to 25 mL of 1,4-dioxane containing 0.944 g piperazine (10.96 mmol, 2 equivalents, M = 86.14 g / mol), reacted at 100 °C for 24 h, filtered, thoroughly washed with 1,4-dioxane and methanol, and dried to obtain catalyst G.
[0070] Comparative Example 2
[0071] The method is the same as in Example 1, except that chloropropyltrimethoxysilane is not used, and it is replaced by propyltrimethoxysilane in equal volume. The corresponding amount of piperazine is increased, as follows:
[0072] (1) At 38℃, 4g of surfactant P123 was dissolved in 130ml of H2O and 21ml of concentrated hydrochloric acid, and the mixture was stirred until the solution was homogeneous. 9.8g of tetraethyl orthosilicate (TEOS) was added and the mixture was stirred for 20 hours. The mixture was placed in a constant temperature oven at 100℃ for 24 hours to crystallize. After cooling to room temperature, the mixture was filtered and washed multiple times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material SBA-15.
[0073] (2) Weigh 2.0 g of the above SBA-15 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 1 mL of propyltrimethoxysilane (M = 164.27 g / mol, e = 0.932 g / cm³). 3 The mixture was refluxed in a nitrogen atmosphere for 16 hours, filtered, thoroughly washed with toluene, and dried to obtain hydrophobic mesoporous silica material SBA-15.
[0074] (3) Take the hydrophobic mesoporous silica material SBA-15 obtained above and add it to 25 mL of 1,4-dioxane containing 0.944 g piperazine (10.96 mmol, 2 equivalents, M = 86.14 g / mol). React at 100 °C for 24 h. Filter, wash thoroughly with 1,4-dioxane and methanol, and dry to obtain catalyst H.
[0075] Comparative Example 3
[0076] The method is the same as in Example 1, except that the ratio of chloropropyltrimethoxysilane to propyltrimethoxysilane is 0.38, as detailed below:
[0077] (1) At 38℃, 4g of surfactant P123 was dissolved in 130ml of H2O and 21ml of concentrated hydrochloric acid, and the mixture was stirred until the solution was homogeneous. 9.8g of tetraethyl orthosilicate (TEOS) was added and the mixture was stirred for 20 hours. The mixture was placed in a constant temperature oven at 100℃ for 24 hours to crystallize. After cooling to room temperature, the mixture was filtered and washed several times with deionized water. After drying, it was calcined at 550℃ for 6 hours to obtain mesoporous silica material SBA-15.
[0078] (2) Weigh 2.0 g of the above SBA-15 and place it in 25 mL of dry toluene. Reflux under a nitrogen atmosphere for 1 h. Add 0.3 mL of chloropropyltrimethoxysilane (M = 198.72 g / mol, e = 1.09 g / cm³). 3 ) and 0.75 mL of propyltrimethoxysilane (M = 164.27 g / mol, e = 0.932 g / cm) 3 The mixture was refluxed in a nitrogen atmosphere for 16 hours, filtered, thoroughly washed with toluene, and dried to obtain chloroalkylated and hydrophobic mesoporous silica material SBA-15.
[0079] (3) The chloroalkylated and hydrophobic mesoporous silica material SBA-15 obtained above was added to 25 mL of 1,4-dioxane containing 0.282 g piperazine (3.27 mmol, 2 equivalents, M = 86.14 g / mol), and reacted at 100 °C for 24 h. After filtration, 1,4-dioxane and methanol were thoroughly washed and dried to obtain catalyst I.
[0080] [Test Example]
[0081] 182 mg of sorbitol was added to a high-pressure reactor, followed by 50 mg of catalyst AF, 720 mg of dimethyl carbonate (DMC), and 2 mL of methanol. The reaction was carried out at 90 °C for 12 h. The results are shown in Table 1. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was separated from the catalyst. The catalyst was washed with methanol, dried, and then recycled. The conversion rate and selectivity of the recycled catalyst are shown in Table 3.
[0082] Table 1 Performance of catalyst AF in the reaction of sorbitol and DMC
[0083] catalyst Sorbitol conversion rate, % Isosorbide selectivity, % A 97 90 B 98 90 C 99 90 D 92 90 E 99 95 F 93 90
[0084] [Comparative Test Examples]
[0085] 182 mg sorbitol, 50 mg catalyst GI, 720 mg dimethyl carbonate (DMC), and 2 mL methanol were added to a high-pressure reactor and the reaction was carried out at 90 °C for 12 h. The results are shown in Table 2. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was separated from the catalyst. The catalyst was washed with methanol, dried, and recycled. The conversion rate and selectivity of the recycled catalyst are shown in Table 3.
[0086] Table 2 Performance of catalyst GI in the reaction of sorbitol and DMC
[0087] catalyst Sorbitol conversion rate, % Isosorbide selectivity, % G 90 75 H 0 0 I 40 80
[0088] Table 3 Conversion and selectivity of catalyst AI recycling
[0089]
[0090] The above embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to specifically limit the present invention. Those skilled in the art can make other variations or modifications based on the above description, and it is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. A catalyst for the preparation of isosorbide, characterized in that, The catalyst is an organic / inorganic hybrid material, wherein the organic component includes a functional group containing two or more nitrogen atoms and a nitrogen-free hydrophobic group, and the inorganic component is a mesoporous silica material; the nitrogen-free hydrophobic group is at least one of methyl, dimethyl, trimethyl, ethyl, and propyl; the molar ratio of the functional group containing two or more nitrogen atoms to the nitrogen-free hydrophobic group is 0.5~7. The catalyst preparation method includes: reacting mesoporous silica material with a haloalkylating agent and a hydrophobicating agent, and then adding a compound containing two or more N atoms in its molecule to react, thereby obtaining the catalyst.
2. The catalyst according to claim 1, characterized in that, The functional group containing two or more N atoms is obtained by reacting a compound containing two or more N atoms with a haloalkyl group; and / or, The compound containing two or more N atoms is at least one of DBU, TBD, DABCO, imidazole, imidazoline, pyrazole, and piperazine; and / or, The haloalkyl group is at least one of chloromethyl, chloropropyl, bromopropyl, and iodopropyl.
3. A method for synthesizing isosorbide catalyst, comprising the following steps: (1) Synthesis of mesoporous silica materials; (2) Disperse the mesoporous silica material obtained in step (1) into solvent I, and under an inert atmosphere, reflux for the first time, add haloalkylating agent and hydrophobicating agent, and reflux for the second time to obtain pore haloalkylated and hydrophobic mesoporous silica material; (3) Disperse the pore-shaped haloalkylated and hydrophobic mesoporous silica material obtained in step (2) into solvent II, and under an inert atmosphere, add a compound containing two or more N atoms in the molecule to react and obtain the isosorbide catalyst.
4. The synthesis method according to claim 3, characterized in that, The mesoporous silica material is a mesoporous silica material with disordered or ordered pores.
5. The synthesis method according to claim 4, characterized in that, The mesoporous silica material is selected from at least one of SBA-15, MCM-41, MCM-48, KIT-6, FDU-5, AMS-10, HMS, MSU, KIT-1 and TUD-1.
6. The synthesis method according to claim 3, characterized in that, The haloalkylating agent is selected from at least one of chloromethyltrimethoxysilane, chloropropyltrimethoxysilane, bromopropyltrimethoxysilane, and iodopropyltrimethoxysilane; and / or, The hydrophobicating agent is selected from at least one of methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, hexamethyldisilazane, and trimethylchlorosilane; and / or, Solvent I is selected from at least one of toluene, n-hexane, and cyclohexane, and solvent II is 1,4-dioxane.
7. The synthesis method according to claim 3, characterized in that, The molar ratio of the haloalkylating agent to the hydrophobicating agent is 0.5 to 7.
8. The synthesis method according to claim 3, characterized in that, The volume of solvent I, based on the mass of the mesoporous silica material, is 5~500 mL / g; and / or, The volume of solvent II is 5 to 500 mL / g, based on the mass of a compound containing two or more N atoms in its molecule.
9. The synthesis method according to claim 3, characterized in that, The compound containing two or more N atoms is selected from at least one of DBU, TBD, DABCO, imidazole, imidazoline, pyrazole, piperazine and its derivatives.
10. The synthesis method according to claim 3, characterized in that, The mass ratio of the mesoporous silica material to the haloalkylating agent is 1 to 10; and / or, The mass ratio of the compound containing two or more N atoms in the molecule to the mass ratio of the porous haloalkylated and hydrophobic mesoporous silica material is 0.1 to 1.
2.
11. The synthesis method according to claim 3, characterized in that, In step (2), the first reflux time is ≥0.2 h; the second reflux time is ≥1 h; and / or, In step (3), the reaction temperature is 25~101℃ and the reaction time is ≥ 6 h.
12. The synthesis method according to claim 11, characterized in that, In step (2), the first reflux time is 0.5~2 h; the second reflux time is 4~72 h; and / or, In step (3), the reaction temperature is 60~101℃ and the reaction time is 6~72h.
13. The use of the catalyst according to any one of claims 1-2 or the catalyst prepared by any one of the synthetic methods according to claims 3-12 in the preparation of isosorbide.