Catalyst for preparing isosorbide, preparation method of catalyst and method for preparing isosorbide through reaction of sorbitol and dimethyl carbonate

Abstract

The invention discloses a catalyst for preparing isosorbide, a preparation method of the catalyst and a method for preparing isosorbide through reaction of sorbitol and dimethyl carbonate. The catalyst for preparing the isosorbide comprises macroporous ion exchange resin, and the macroporous ion exchange resin is provided with spherical or sphere-like pore channels and comprises a styrene type resin matrix and functional groups, the functional group is derived from a product obtained by carrying out chloromethylation on the styrene type resin matrix and then reacting the chloromethylated styrene type resin matrix with a heterocyclic compound containing more than two N atoms and a derivative of the heterocyclic compound. The catalyst can efficiently catalyze the reaction of sorbitol and dimethyl carbonate to prepare isosorbide, and has the characteristics of easy separation and high selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of ion exchange resins, and in particular to a catalyst for preparing isosorbide and a preparation method thereof, and a method for preparing isosorbide by reacting sorbitol with dimethyl carbonate. Background Art

[0002] Isosorbide (scientific name: 1,4:3,6-dianhydro-D-glucitol) is an important bio-based raw material second only to lactic acid, and is also the only sugar alcohol monomer that has been industrially produced. The industrial production of isosorbide currently mainly adopts a three-step process: (1) starch (or cellulose) is hydrolyzed to obtain glucose, (2) glucose is catalytically hydrogenated to sorbitol, and (3) sorbitol is dehydrated again to obtain isosorbide. The third step mainly uses sulfuric acid as a catalyst, and the reaction temperature is 127°C and the reaction is carried out under vacuum conditions for 1 to 5 hours. The yield of isosorbide is 70-77%. Using liquid acid as a catalyst has a higher catalytic efficiency, but there are problems such as a complex separation process, the catalyst cannot be recycled, and the requirements for the reaction equipment are stringent. Therefore, this production process has poor atom economy and is not environmentally friendly. Based on this, people turned their attention to solid acid catalysis and developed a variety of solid acid catalysts, such as sulfonated mesoporous materials, acidic ion exchange resins, supported metal salts, metal phosphates, acidic zeolites, sulfated and phosphated metal oxides, supported heteropoly acids, etc. However, the yield of isosorbide obtained by these solid acid catalysis is mostly 70-85%, which still needs to be further improved, and the reaction conditions are harsh (high temperature, vacuum or microwave assistance, or reducing atmosphere).

[0003] Sorbitol and dimethyl carbonate are reacted in the presence of a catalyst such as sodium methoxide, K 2 CO 3 The method of obtaining isosorbide under the action of triethylenediamine (DABCO), 1,8-diazobispirocyclic (5.4.0) undec-7-ene (DBU) or 1,5,7-triazidobicyclic (4.4.0) dec-5-ene (TBD) is a route for the efficient production of isosorbide. In particular, with DBU as a catalyst, the sorbitol conversion rate and isosorbide selectivity can even reach 100%, and after separation and purification, the isosorbide yield is 98%. However, these catalysts are homogeneous and used in large quantities, and there are also problems such as difficulty in separation, large discharge of three wastes, and inability to carry out large-scale continuous production. Based on this, people are committed to developing multiphase catalysts, but the multiphase catalysts currently developed have low selectivity for isosorbide (such as CN108126749A). Therefore, how to develop a catalyst that has both easy separation and high selectivity for the preparation of isosorbide by the reaction of sorbitol and dimethyl carbonate has become the key. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a catalyst for preparing isosorbide and a preparation method thereof, and a method for preparing isosorbide by reacting sorbitol with dimethyl carbonate. The catalyst can efficiently catalyze the reaction of sorbitol and dimethyl carbonate to prepare isosorbide, and has the characteristics of easy separation and high selectivity. The preparation method provided by the present invention is simple and feasible, and can provide a reference for preparing other catalysts with higher performance.

[0005] One of the purposes of the present invention is to provide a catalyst for preparing isosorbide, comprising a macroporous ion exchange resin having spherical or quasi-spherical pores, comprising a styrene-type resin matrix and a functional group, wherein the functional group is derived from a product obtained by reacting the styrene-type resin matrix with a heterocyclic compound containing two or more N atoms and its derivatives after chloromethylation.

[0006] In a preferred embodiment of the present invention,

[0007] The macroporous ion exchange resin has a minimum pore size of 20 to 500 nm, preferably 70 to 200 nm, more preferably 70 to 120 nm; and / or,

[0008] The macroporous ion exchange resin is in the form of spherical or quasi-spherical particles, and its particle size is preferably in the range of 350 to 600 μm; and / or,

[0009] The pore size of the macroporous ion exchange resin is uniform and adjustable; and / or,

[0010] The styrene-type resin matrix is ​​prepared by using modified silica nanoparticles as pore-forming agents; the present invention uses modified silica nanoparticles as pore-forming agents (template agents or pore-forming agents) to successfully synthesize a styrene-type resin matrix with spherical or quasi-spherical pores and uniform and adjustable pore sizes; and / or,

[0011] The chloromethylation agent used in the chloromethylation is selected from at least one of chloromethyl ether, chloroethyl ether and chloromethyl ethyl ether, preferably at least one of chloromethyl ether and chloromethyl ethyl ether; and / or,

[0012] The heterocyclic compound containing more than two N atoms and its derivatives are at least one of 1,8-diazobispiro (5.4.0) undec-7-ene (DBU), 1,5,7-triazidobicyclo (4.4.0) dec-5-ene (TBD), triethylenediamine (DABCO), imidazole, imidazoline, pyrazole, piperazine and their derivatives, preferably at least one of 1,8-diazobispiro (5.4.0) undec-7-ene, 1,5,7-triazidobicyclo (4.4.0) dec-5-ene, triethylenediamine and their derivatives.

[0013] In a preferred embodiment of the present invention,

[0014] The most possible particle size of the modified silica nanoparticles is 20 to 500 nm, preferably 70 to 200 nm, more preferably 70 to 120 nm; and / or,

[0015] The modified silicon dioxide nanoparticles are obtained by modifying silicon dioxide nanoparticles with a silane coupling agent containing double bonds; the size change of the silicon dioxide nanoparticles before and after the modification is very small and can be ignored.

[0016] In a preferred embodiment of the present invention,

[0017] The double bond-containing silane coupling agent is selected from at least one of allyltriethoxysilane, allyltrimethoxysilane, 3-butenetriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, diethoxymethylvinylsilane and methylvinyldimethoxysilane; and / or,

[0018] The most possible particle size of the silica nanoparticles before modification is 20 to 500 nm, preferably 70 to 200 nm, more preferably 70 to 120 nm; and / or,

[0019] The silica nanoparticles before modification can be obtained from commercial sources or prepared by any method in the prior art. In the present invention, the silica nanoparticles before modification are preferably obtained by hydrolysis and polycondensation of silicate compounds; preferably,

[0020] The preparation process of the silica nanoparticles before modification may specifically include the following steps: uniformly mixing alcohol, water and a catalyst, and then adding a silicate compound to react to obtain the silica nanoparticles before modification; wherein the alcohol is preferably at least one of anhydrous ethanol and anhydrous methanol, and / or the catalyst is preferably at least one of ammonia water and sodium carbonate, and / or the volume ratio of alcohol to water is (1-15):1, and / or the mass ratio of the catalyst to water is (0.01-1):1, and / or the volume ratio of the silicate compound to water is (0.1-0.8):1, and / or the reaction temperature is preferably 10-60°C, and the reaction time is preferably 0.1-5h; preferably, the reaction is carried out under stirring, and the stirring rate is preferably 300-800rpm.

[0021] The silicate compound is selected from at least one of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate and butyl orthosilicate; and / or,

[0022] The volume ratio of the double-bond-containing silane coupling agent to the silicate compound is 0.1 to 0.8, preferably 0.2 to 0.4; and / or,

[0023] The modification conditions include: a temperature of 10 to 60° C., preferably 20 to 40° C.; and / or a time of 0.1 to 12 h, preferably 0.5 to 5 h.

[0024] In a preferred embodiment of the present invention,

[0025] The second object of the present invention is to provide a method for preparing a catalyst for preparing isosorbide according to one of the objects of the present invention, comprising the steps of preparing a styrene-type resin matrix, then chloromethylating the styrene-type resin matrix and then reacting it with a heterocyclic compound containing two or more N atoms and its derivatives.

[0026] In a preferred embodiment of the present invention,

[0027] The method comprises:

[0028] (1) polymerizing the components including styrene monomers, comonomers, modified silica nanoparticles, and a dispersant under the action of an initiator and then dispersing them in an acid or alkaline solution for treatment to obtain the styrene-based resin matrix;

[0029] (2) Chloromethylating the styrene-type resin matrix obtained in step (1) and then reacting it with a heterocyclic compound containing two or more N atoms and its derivatives to obtain the macroporous ion exchange resin.

[0030] In a preferred embodiment of the present invention,

[0031] In step (1),

[0032] The styrene monomer is selected from at least one of styrene and its derivatives, preferably selected from at least one of styrene, α-methylstyrene and 4-butylstyrene; and / or,

[0033] The comonomer is selected from at least one of divinylbenzenes, preferably at least one of diisopropenylbenzene and divinylbenzene; and / or,

[0034] The dispersant is selected from at least one of polyvinyl alcohol, gelatin, starch, methyl cellulose, bentonite, and calcium carbonate, preferably at least one of polyvinyl alcohol and gelatin; and / or,

[0035] The initiator is selected from at least one of a peroxide initiator and an azo initiator, preferably at least one of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, and cumene hydroperoxide, more preferably at least one of benzoyl peroxide and azobisisobutyronitrile; and / or,

[0036] The acid solution is an HF aqueous solution; and / or, the alkaline solution is at least one of an aqueous ammonia solution, an alkali metal carbonate aqueous solution, and an alkali metal hydroxide aqueous solution, preferably at least one of an aqueous ammonia solution, an aqueous sodium carbonate aqueous solution, an aqueous sodium hydroxide solution, and an aqueous potassium hydroxide solution; and / or, the concentration of the acid or alkaline solution is 0.005-1.0 mol / L, preferably 0.05-1.0 mol / L; the amount of the acid or alkaline solution is at least enough to completely disperse the resin before treatment in the acid or alkaline solution, preferably, the amount of the acid or alkaline solution is 5-40 mL of the acid or alkaline solution for 1 g of the resin before treatment; in the present invention, the acid or alkaline treatment is to remove the silicon dioxide nanoparticles in the resin, thereby generating spherical or quasi-spherical macropores with uniform and adjustable pore sizes in the resin; the pores of the styrene-type resin matrix prepared by the method are substantially not deformed or only slightly deformed relative to the shape of the modified silicon dioxide (pore-forming agent), and the pore size of the styrene-type resin matrix can be conveniently adjusted by adjusting the size of the modified silicon dioxide nanoparticles; and / or,

[0037] The mass ratio of the styrene monomer, comonomer, modified silica nanoparticles, dispersant and initiator is 1: (0.01-0.05): (0.001-0.2): (0.04-0.15): (0.001-0.1), preferably 1: (0.01-0.03): (0.001-0.1): (0.04-0.1): (0.001-0.02); and / or

[0038] The polymerization conditions include: a temperature of 40 to 120° C., and / or a time of 10 to 72 hours; preferably, the polymerization is carried out in a step-by-step heating manner, preferably stirring at 40 to 50° C. for 0.5 to 2 hours for prepolymerization, then heating to 60 to 85° C. for reaction for 1 to 24 hours, then heating to 85 to 95° C. for reaction for 1 to 24 hours, and finally heating to 95 to 120° C. for reaction for 1 to 24 hours; and / or,

[0039] The treatment conditions include: a temperature of 10 to 100°C, preferably 60 to 100°C; and / or a time of 0.5 to 12 hours, preferably 0.5 to 3 hours; preferably, the treatment includes the step of dispersing the resin before treatment into the acid or alkali solution, and stirring the reaction at 10 to 100°C and 300 to 800 rpm for 0.5 to 12 hours.

[0040] Conventional nano-carbon materials in the art, such as graphene, etc., may also be added to the polymer raw materials of the styrene-based resin matrix in step (1) of the present invention. The amount used is also conventional, and those skilled in the art may add it according to actual conditions.

[0041] In a preferred embodiment of the present invention,

[0042] In step (2),

[0043] The chloromethylation comprises the step of carrying out a functionalization reaction between a styrene-based resin matrix and a chloromethylation agent in the presence of a catalyst; preferably,

[0044] The amount of the chloromethylation agent is 200-500% of the weight of the styrene-based resin matrix, preferably 400-500%; and / or,

[0045] The catalyst is zinc chloride; and / or,

[0046] The amount of the catalyst is 20 to 70% by weight of the styrene-based resin matrix, preferably 20 to 50%; and / or,

[0047] The conditions of the functionalization reaction include: a temperature of 30 to 60° C., preferably 30 to 50° C., and / or a time of 8 to 30 hours, preferably 8 to 15 hours.

[0048] In a preferred embodiment of the present invention,

[0049] In step (2),

[0050] The amount of the heterocyclic compound containing two or more N atoms and its derivatives is 20 to 100% of the weight of the styrene-based resin matrix, preferably 40 to 90%; and / or,

[0051] The conditions for reacting with the heterocyclic compound containing more than two N atoms and its derivatives include: reacting at reflux temperature for more than 6 hours, preferably reacting for 6 to 72 hours.

[0052] The present invention can adopt the following specific technical solutions:

[0053] The method for synthesizing the macroporous ion exchange resin comprises the following steps:

[0054] 1) first synthesizing silica nanoparticles, and then modifying them with a silane coupling agent containing a double bond to obtain modified silica nanoparticles;

[0055] 2) polymerizing the modified silica nanoparticles prepared in step 1) together with a styrene monomer, a comonomer and a dispersant under the action of an initiator, and dispersing the obtained beads into an acid or alkaline solution for 0.5 to 12 hours to obtain a styrene-based resin matrix;

[0056] 3) reacting the styrene-type resin matrix prepared in step 2) with a chloromethylation agent and a heterocyclic compound containing two or more N atoms and its derivatives in sequence to obtain the macroporous ion exchange resin.

[0057] In the above technical solution, preferably, in step 3), a chloromethylation agent and a zinc chloride catalyst are added to the styrene-type resin matrix to carry out a functionalization reaction. After the reaction is completed, the macroporous chlorine balls are obtained by washing with methanol and water and drying.

[0058] In the above technical solution, preferably, the weight of the chloromethylation agent is 200-500% of the weight of the styrene type resin matrix, preferably 400-500%, and the weight of the zinc chloride catalyst is 20-70% of the weight of the styrene type resin matrix, preferably 20-50%.

[0059] In the above technical solution, preferably, in step 3), a solvent and a heterocyclic compound containing two or more N atoms and its derivatives are added to the macroporous chlorine ball to carry out a reaction; after the reaction is completed, the ball is washed with water and dried.

[0060] In the above technical solution, preferably, the solvent is selected from 1,4-dioxane;

[0061] In the above technical solution, preferably, the weight of the solvent is 200-700% of the weight of the macroporous chlorine balls.

[0062] In the above technical solution, preferably, the weight of the heterocyclic compound containing two or more N atoms and its derivatives in step 3) is 20 to 100% of the weight of the styrene-type resin matrix, preferably 40 to 90%.

[0063] The third object of the present invention is to provide a method for preparing isosorbide by reacting sorbitol with dimethyl carbonate, comprising the step of reacting sorbitol with dimethyl carbonate in the presence of the catalyst of the first object of the present invention or the catalyst prepared by the method of the second object of the present invention.

[0064] In a preferred embodiment of the present invention,

[0065] The molar ratio of dimethyl carbonate to sorbitol is (2-50):1, preferably (5-15):1; and / or,

[0066] The amount of the catalyst is 10-50% of the mass of sorbitol, preferably 20-40%; and / or,

[0067] The reaction conditions include: reaction temperature of 80 to 200° C., preferably 80 to 120° C., and reaction time of 1 to 72 hours, preferably 4 to 24 hours.

[0068] Beneficial effects of the present invention:

[0069] (1) The catalyst of the present invention is a heterogeneous catalyst, which effectively solves the problems of difficult separation and low product selectivity of the catalyst for preparing isosorbide in the prior art.

[0070] (2) The method provided by the present invention is simple and feasible.

[0071] (3) Using the catalyst of the present invention, the sorbitol conversion rate is ≥99%, and the isosorbide selectivity is ≥92%. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a SEM photograph of the macroporous ion exchange resin prepared in Example 1.

[0073] Figure 2 is a SEM photograph of the ion exchange resin prepared in Comparative Example 2. DETAILED DESCRIPTION

[0074] The present invention is described in detail below in conjunction with specific embodiments and drawings. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0075] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0076] The morphology of the resins prepared in the examples and comparative examples was measured by scanning electron microscopy (SEM); SiO 2 The size of nanoparticles was measured using a nanoparticle size potential analyzer (Nano ZS90); the pore size of the resin channel was measured using a mercury intrusion instrument Pascal 140 / 240.

[0077] [Example 1]

[0078] 71.4 mL of anhydrous ethanol, 10 mL of deionized water and 1.57 mL of ammonia water (ammonia water concentration 14.84 mol / L) were evenly mixed and placed in a water bath at 30 °C for magnetic stirring at a stirring speed of 400 rpm. After the temperature was balanced, 3 mL of ethyl orthosilicate was quickly added to the above reaction solution and reacted for 1 h to obtain solid SiO 2 Nanoparticles, the most probable particle size of which is 100 nm, were added with 1 mL of allyltriethoxysilane and continued to react for 1 h. After centrifugation, they were fully washed with ethanol and dried to obtain modified SiO 2 Nanoparticles.

[0079] Dissolve 4 g of gelatin in 260 mL of deionized water and disperse evenly by ultrasonication; take 58 g of styrene, 1.2 g of divinylbenzene, 0.5 g of benzoyl peroxide and 5.0 g of modified SiO 2The nanoparticles were ultrasonically dispersed for 30 minutes. Added to the previous gelatin aqueous solution, stirred at 400 rpm for 2 hours at 40°C for prepolymerization, gradually heated to 80°C, reacted for 5 hours, then heated to 90°C for 5 hours, and finally heated to 98°C for 6 hours. After the reaction, the upper liquid was poured out, washed and filtered with hot water, dried at 80°C, and sieved to collect resin beads with a particle size range of 350 to 600 μm. The obtained resin beads were then dispersed in 1000 mL of 0.6 mol / L Na 2 CO 3 The reaction was stirred at 400 rpm at 80°C for 1 hour, and the product was collected, washed thoroughly with water, and dried to obtain a styrene-type resin matrix.

[0080] Take 50g of styrene-type resin matrix and 250ml of chloromethyl ether, let stand at room temperature for 4 hours, then stir at 400rpm and add 15g of zinc chloride as a catalyst, heat to 60°C for reaction for 8 hours, then cool to room temperature, filter out the chlorinated mother liquor, wash thoroughly with methanol, then dry and disperse in 800ml of 1,4-dioxane containing 25g of DBU, reflux for 24h, filter, wash thoroughly with 1,4-dioxane and methanol, and dry to obtain macroporous ion exchange resin A (i.e., catalyst A for preparation of isosorbide). The particle size of the obtained macroporous ion exchange resin A is 350-600μm; the SEM photo of the obtained macroporous ion exchange resin A is shown in Figure 1 As shown, it can be seen that the pores of the macroporous ion exchange resin A are spherical or quasi-spherical, and the pore size is uniform. The most probable pore size is measured to be 99 nm.

[0081] [Example 2]

[0082] 71.4 mL of anhydrous ethanol, 10 mL of deionized water and 3 mL of ammonia water (ammonia water concentration 14.84 mol / L) were evenly mixed and placed in a water bath at 30 °C for magnetic stirring at a stirring speed of 400 rpm. After the temperature was balanced, 3 mL of ethyl orthosilicate was quickly added to the above reaction solution and reacted for 1 h to obtain solid SiO 2 Nanoparticles, the most probable particle size of which is 80 nm, were added with 1 mL of allyl triethoxysilane and continued to react for 1 h. After centrifugation, they were fully washed with ethanol and dried to obtain modified SiO 2 Nanoparticles.

[0083] Dissolve 4 g of gelatin in 260 mL of deionized water and disperse evenly by ultrasonication; take 58 g of styrene, 1.2 g of divinylbenzene, 0.5 g of benzoyl peroxide and 3.0 g of modified SiO 2The nanoparticles were ultrasonically dispersed for 30 minutes, added to the previous gelatin aqueous solution, stirred at 400 rpm for 2 hours at 40°C for prepolymerization, gradually heated to 80°C, reacted for 5 hours, then heated to 90°C for 5 hours, and finally heated to 98°C for 6 hours. After the reaction, the upper liquid was poured out, washed with hot water and filtered, dried at 80°C, sieved and collected resin beads with a particle size in the range of 350 to 600 μm, and then the obtained resin beads were dispersed in 1000 mL of 0.05 mol / L NaOH aqueous solution, stirred at 400 rpm at 80°C for 1 hour, the product was collected, washed with water, and dried to obtain a styrene-type resin matrix.

[0084] Take 50g of styrene-type resin matrix and 200mL of chloromethyl ether, stand at room temperature for 4 hours, stir at 400rpm, add 15g of zinc chloride as catalyst, heat to 40℃, react for 10 hours, cool to room temperature, filter out chlorinated mother liquor, wash thoroughly with methanol, disperse into 600mL of 1,4-dioxane containing 30g of TBD after drying, reflux for 24h, filter, wash thoroughly with 1,4-dioxane and methanol, and dry to obtain macroporous ion exchange resin B (i.e. catalyst B for preparation of isosorbide). The particle size of the obtained macroporous ion exchange resin B is 350-600μm; the pores of the obtained macroporous ion exchange resin B are spherical or quasi-spherical, and the pore size is uniform, and the most probable pore size is 79nm.

[0085] [Example 3]

[0086] 71.4 mL of anhydrous ethanol, 10 mL of deionized water and 3 mL of ammonia water (ammonia water concentration 14.84 mol / L) were evenly mixed and placed in a water bath at 30 °C for magnetic stirring at a stirring speed of 400 rpm. After the temperature was balanced, 4 mL of ethyl orthosilicate was quickly added to the above reaction solution and reacted for 1 h to obtain solid SiO 2 Nanoparticles, the most probable particle size of which is 90 nm, were added with 1 mL of allyl triethoxysilane and continued to react for 1 h. After centrifugation, they were fully washed with ethanol and dried to obtain modified SiO 2 Nanoparticles.

[0087] Dissolve 4 g of gelatin in 260 mL of deionized water and disperse evenly by ultrasonication; Take 58 g of styrene, 1.2 g of divinylbenzene, 0.5 g of benzoyl peroxide and 4.0 g of modified SiO 2The nanoparticles were ultrasonically dispersed for 30 minutes. They were added to the previous gelatin aqueous solution, stirred at 400 rpm for 2 hours at 40°C for prepolymerization, gradually heated to 80°C, reacted for 5 hours, then heated to 90°C for 5 hours, and finally heated to 98°C for 6 hours. After the reaction, the upper liquid was poured out, washed with hot water and filtered, dried at 80°C, and sieved to collect resin beads with a particle size in the range of 350 to 600 μm. The obtained resin beads were then dispersed in 1000 mL of 0.01 mol / L KOH aqueous solution, stirred at 400 rpm at 80°C for 1 hour, the product was collected, washed thoroughly with water, and dried to obtain a styrene-type resin matrix.

[0088] Take 50g of styrene-type resin matrix and 250ml of chloromethyl ether, stand at room temperature for 4 hours, stir at 400rpm, add 15g of zinc chloride as a catalyst, heat to 60℃, react for 8 hours, cool to room temperature, filter out the chlorinated mother liquor, wash with methanol, dry and disperse in 500ml of 1,4-dioxane containing 40g of DABCO, reflux for 24h, filter, wash with 1,4-dioxane and methanol, and dry to obtain macroporous ion exchange resin C (i.e. catalyst C for preparation of isosorbide). The particle size of the obtained macroporous ion exchange resin C is 350-600μm; the pores of the obtained macroporous ion exchange resin C are spherical or quasi-spherical, and the pore size is uniform, and the most probable pore size is 90nm.

[0089] [Comparative Example 1]

[0090] 71.4 mL of anhydrous ethanol, 10 mL of deionized water and 1.57 mL of ammonia water (ammonia water concentration 14.84 mol / L) were evenly mixed and placed in a water bath at 30 °C for magnetic stirring at a stirring speed of 400 rpm. After the temperature was balanced, 3 mL of ethyl orthosilicate was quickly added to the above reaction solution and reacted for 1 h to obtain solid SiO 2 The nanoparticles, whose most probable particle size was 100 nm, were washed extensively with ethanol and dried after centrifugation.

[0091] Dissolve 4 g of gelatin in 260 mL of deionized water and disperse evenly by ultrasonication; Take 58 g of styrene, 1.2 g of divinylbenzene, 0.5 g of benzoyl peroxide and 5.0 g of solid SiO 2 The nanoparticles were ultrasonically dispersed for 30 min and SiO 2Nanoparticles are difficult to disperse evenly. Add to the previous gelatin aqueous solution, stir at 400 rpm for 2 hours at 40°C for prepolymerization, gradually heat to 80°C, react for 5 hours, then heat to 90°C for 5 hours, and finally heat to 98°C for 6 hours. During the entire reaction process, most of the silica nanoparticles are distributed on the outside of the suspended polymerized beads. After the reaction is completed, pour out the upper liquid, wash and filter with hot water, dry at 80°C, and sieve to collect resin beads with a particle size range of 350-600μm. Then disperse the obtained resin beads into 1000mL of 0.6mol / LNa 2 CO 3 The mixture was treated in an aqueous solution at 80°C for 1 hour, washed thoroughly with water and then dried.

[0092] Take 50g of the resin beads treated as above and 250ml of chloromethyl ether, stand at room temperature for 4 hours, stir at 400rpm, add 15g of zinc chloride as a catalyst, heat to 60°C for reaction for 8 hours, cool to room temperature, filter out the chlorinated mother liquor, wash thoroughly with methanol, dry and disperse in 800ml of 1,4-dioxane containing 25g of DBU, reflux for 24h, filter, wash thoroughly with 1,4-dioxane and methanol, and dry to obtain ion exchange resin catalyst D. The obtained ion exchange resin D is substantially non-porous.

[0093] [Comparative Example 2]

[0094] Dissolve 4g of gelatin in 260mL of deionized water and disperse it evenly by ultrasonication; take 58g of styrene, 1.2g of divinylbenzene, 0.5g of benzoyl peroxide and 5g of toluene and disperse them by ultrasonication for 30min. Add to the previous gelatin aqueous solution, stir at 400rpm for 2 hours at 40℃ for prepolymerization, gradually heat to 80℃, react for 5 hours, then heat to 90℃ for 5 hours, and finally heat to 98℃ for 6 hours. After the reaction, pour out the upper liquid, wash and filter with hot water, dry at 80℃, and sieve to collect resin beads with a particle size range of 350-600μm. Then disperse the obtained resin beads into 1000mL of 0.6mol / LNa 2 CO 3 The mixture was stirred at 400 rpm for 1 hour at 80°C in an aqueous solution, and then washed thoroughly with water and dried.

[0095] Take 50g of the resin beads treated above and 250ml of chloromethyl ether, let stand at room temperature for 4 hours, then stir at 400rpm and add 15g of zinc chloride as a catalyst, heat to 60°C for 8 hours, cool to room temperature, filter out the chlorinated mother liquor, wash thoroughly with methanol, dry and disperse in 800ml of 1,4-dioxane containing 25g of DBU, reflux for 24h, filter, wash thoroughly with 1,4-dioxane and methanol, and dry to obtain ion exchange resin E. The SEM photo of the obtained ion exchange resin E is shown in the figure. Figure 2 As shown by Figure 2 It can be seen that the pores produced by the traditional pore-forming agent toluene do not have any fixed shape and are not uniform in size.

[0096] [Test Example 1]

[0097] 182 mg of sorbitol, 50 mg of catalyst A or B or C, 720 mg of dimethyl carbonate, and 2 mL of methanol were added to the reaction kettle at 90° C. and reacted for 12 hours. The results are shown in Table 1.

[0098] Table 1. Catalytic performance of catalysts AC in the reaction of sorbitol and DMC

[0099] catalyst Sorbitol conversion rate / 100% Isosorbide selectivity / 100% A 99.5 93.0 B 99.5 92.8 C 99.3 92.8

[0100]

Comparative test example 1

[0101] 182 mg of sorbitol, 50 mg of catalyst D or E, 720 mg of dimethyl carbonate, and 2 mL of methanol were added to the reaction kettle at 90° C. for 12 h. The results are shown in Table 2.

[0102] Table 2. Catalytic performance of catalyst D or E in the reaction of sorbitol and DMC

[0103] catalyst Sorbitol conversion rate / 100% Isosorbide selectivity / 100% D 90.3 70.6 E 95.2 78.0

[0104] It can be seen from Example 1, Comparative Example 1 and Tables 1-2 that in Example 1 of the present invention, SiO 2 The nanoparticles are modified and then used as pore-forming agents, so that the obtained resin has large pores and uniform pore size, thereby significantly improving the catalytic performance of the reaction of sorbitol and dimethyl carbonate to prepare isosorbide. It can be seen from Example 1, Comparative Example 2 and Tables 1-2 that compared with the ion exchange resin obtained by the traditional pore-forming agent, the macroporous ion exchange resin of Example 1 of the present invention has more regular pores and more uniform pore size, so it performs well in catalyzing the reaction of sorbitol and dimethyl carbonate to prepare isosorbide.

[0105] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, under the technical enlightenment provided by the present invention, as common knowledge in the field, other equivalent variations and improvements can also be made, which should also be regarded as the protection scope of the present invention.

Claims

1. A catalyst for preparing isosorbide, comprising macroporous ion exchange resin. The macroporous ion exchange resin has spherical or quasi-spherical pores, and it includes a styrene-type resin matrix and a functional group. The functional group is derived from the product obtained by chloromethylating the styrene-type resin matrix and then reacting it with a heterocyclic compound containing two or more N atoms and its derivatives.

2. The catalyst according to claim 1, characterized in that: the most probable pore diameter of the macroporous ion exchange resin is 20 - 500 nm, preferably 70 - 200 nm; and / or, the macroporous ion exchange resin is spherical or quasi-spherical particles, and the particle size range is preferably 350 - 600 μm; and / or, the styrene-type resin matrix is prepared using modified silica nanoparticles as a pore-forming agent; and / or, the chloromethylating reagent used for chloromethylation is selected from at least one of chloromethyl methyl ether, chloromethyl ethyl ether, and chloromethyl ethyl ether, preferably at least one of chloromethyl methyl ether and chloromethyl ethyl ether; and / or, the heterocyclic compound containing two or more N atoms and its derivatives is at least one of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, triethylenediamine, imidazoline, pyrazole, piperazine and its derivatives, preferably at least one of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triethylenediamine and its derivatives.

3. The catalyst according to claim 2, characterized in that: the most probable particle size of the modified silica nanoparticles is 20 - 500 nm, preferably 70 - 200 nm; and / or, the modified silica nanoparticles are obtained by modifying silica nanoparticles with a silane coupling agent containing a double bond.

4. The catalyst according to claim 3, characterized in that: the silane coupling agent containing a double bond is selected from at least one of allyl triethoxysilane, allyl trimethoxysilane, 3-butenyl triethoxysilane, vinyl triethoxysilane, vinyl trimethoxysilane, diethoxymethylvinylsilane, and methylvinyldimethoxysilane; and / or, the most probable particle size of the silica nanoparticles before modification is 20 - 500 nm, preferably 70 - 200 nm; and / or, the silica nanoparticles before modification are obtained by hydrolysis and polycondensation of a silicate compound; preferably, the silicate compound is selected from at least one of methyl silicate, ethyl silicate, propyl silicate, and butyl silicate; and / or, the volume ratio of the silane coupling agent containing a double bond to the silicate compound is 0.1 - 0.8, preferably 0.2 - 0.4; and / or, the conditions for modification include: the temperature is 10 - 60 °C, preferably 20 - 40 °C; and / or, the time is 0.1 - 12 h, preferably 0.5 - 5 h.

5. A method for preparing a catalyst according to any one of claims 1-4, comprising preparing a styrene-type resin matrix, and then subjecting the styrene-type resin matrix to chloromethylation and then reacting it with a heterocyclic compound containing two or more N atoms and its derivatives.

6. The preparation method according to claim 5, characterized in that the method comprises: (1) Polymerizing components including styrene monomers, comonomers, modified silica nanoparticles, and a dispersant under the action of an initiator, and then dispersing them in an acid or base solution for treatment to obtain the styrene-type resin matrix; (2) Subjecting the styrene-type resin matrix obtained in step (1) to chloromethylation and then reacting it with a heterocyclic compound containing two or more N atoms and its derivatives to obtain the macroporous ion exchange resin.

7. The preparation method according to claim 6, characterized in that: In step (1), the styrene monomers are selected from at least one of styrene and its derivatives, preferably at least one of styrene, α-methylstyrene, and 4-butylstyrene; and / or, the comonomers are selected from at least one of diene-based benzenes, preferably at least one of diisopropenylbenzene and divinylbenzene; and / or, the dispersant is selected from at least one of polyvinyl alcohol, gelatin, starch, methylcellulose, bentonite, and calcium carbonate, preferably at least one of polyvinyl alcohol and gelatin; and / or, the initiator is selected from at least one of peroxide initiators and azo initiators, preferably at least one of benzoyl peroxide, azobisisobutyronitrile, lauroyl peroxide, and cumene hydroperoxide; and / or, the acid solution is an HF aqueous solution; and / or, the base solution is at least one of an ammonia aqueous solution, an aqueous solution of an alkali metal carbonate, and an aqueous solution of an alkali metal hydroxide, preferably at least one of an ammonia aqueous solution, a sodium carbonate aqueous solution, a sodium hydroxide aqueous solution, and a potassium hydroxide aqueous solution; and / or, the concentration of the acid or base solution is 0.005-1.0 mol / L, preferably 0.05-1.0 mol / L; and / or, the mass ratio of the styrene monomers, comonomers, modified silica nanoparticles, dispersant, and initiator is 1:(0.01-0.05):(0.001-0.2):(0.04-0.15):(0.001-0.1), preferably 1:(0.01-0.03):(0.001-0.1):(0.04-0.1):(0.001-0.02); and / or, the conditions for the polymerization include: the temperature is 40-120 °C, and / or, the time is 10-72 hours; preferably, the polymerization is carried out in a stepwise temperature-raising manner, preferably with stirring at 40-50 °C for 0.5-2 h for pre-polymerization, then raising the temperature to 60-85 °C for reaction for 1-24 h, then raising the temperature to 85-95 °C for reaction for 1-24 h, and finally raising the temperature to 95-120 °C for reaction for 1-24 h; and / or, The conditions for the treatment include: the temperature is 10 to 100 °C, preferably 60 to 100 °C; and / or, the time is 0.5 to 12 h, preferably 0.5 to 3 h.

8. The preparation method according to claim 6, characterized in that: in step (2), the chloromethylation includes the step of subjecting a styrene-based resin matrix to a functionalization reaction with a chloromethylation reagent in the presence of a catalyst; preferably, the amount of the chloromethylation reagent is 200 to 500% by weight of the styrene-based resin matrix, preferably 400 to 500%; and / or, the catalyst is zinc chloride; and / or, the amount of the catalyst is 20 to 70% by weight of the styrene-based resin matrix, preferably 20 to 50%; and / or, the conditions for the functionalization reaction include: the temperature is 30 to 60 °C, preferably 30 to 50 °C, and / or, the time is 8 to 30 h, preferably 8 to 15 h.

9. The preparation method according to claim 6, characterized in that: in step (2), the amount of the heterocyclic compound containing two or more N atoms and its derivatives is 20 to 100% by weight of the styrene-based resin matrix, preferably 40 to 90%; and / or, the conditions for the reaction with the heterocyclic compound containing two or more N atoms and its derivatives include: reacting at the reflux temperature for more than 6 h, preferably reacting for 6 to 72 h.

10. A method for preparing isosorbide by reacting sorbitol with dimethyl carbonate, which includes the step of reacting sorbitol with dimethyl carbonate in the presence of the catalyst according to any one of claims 1-4 or the catalyst prepared by the method according to any one of claims 5-9.

11. The method according to claim 10, characterized in that: the molar ratio of dimethyl carbonate to sorbitol is (2 to 50):1, preferably (5 to 15):1; and / or, the amount of the catalyst is 10 to 50% by mass of sorbitol, preferably 20 to 40%; and / or, the conditions for the reaction include: the reaction temperature is 80 to 200 °C, preferably 80 to 120 °C, and the reaction time is 1 to 72 h, preferably 4 to 24 h.

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