Method for preparing isosorbide through sorbitol dehydration

Abstract

The invention relates to the technical field of isosorbide preparation, and provides a method for preparing isosorbide by sorbitol dehydration, which comprises the following steps: melting sorbitol, adding a solid acid catalyst and an entrainer, and stirring for reaction to obtain isosorbide; the solid acid catalyst comprises a supported sulfonated polystyrene-divinylbenzene catalyst or a supported sulfonated phenolic resin solid acid catalyst. The method for preparing the isosorbide by dehydrating the sorbitol, provided by the invention, has relatively high sorbitol conversion rate and isosorbide yield; compared with an existing isosorbide preparation industrial technology, the method has the advantages that the generation amount of by-products such as water is greatly reduced, the defects that equipment is easy to corrode, continuous production is difficult, products are difficult to separate, the catalyst cannot be repeatedly used and the like when a liquid acid catalyst is used are overcome, and continuous production can be carried out.

Description

Technical Field

[0001] The invention relates to the technical field of isosorbide preparation, and more specifically to a method for preparing isosorbide by dehydrating sorbitol. Background Art

[0002] Isosorbide is an organic diol composed of two furan fused rings. It has a chiral structure and great molecular rigidity. It is an important new bio-based intermediate that can be used for copolymerization modification of polymers such as polycarbonate, polyester, polyurethane, and epoxy resin, and can significantly improve the high-temperature performance and impact resistance of polymers. It can also be used as an organic synthesis intermediate and is widely used in the fields of medicine, food, and cosmetics.

[0003] At present, the industry mainly uses concentrated sulfuric acid and other liquid acids as catalysts and adopts intermittent reactors to synthesize isosorbide. Sorbitol is dehydrated in the first step of acid catalysis to obtain 1,4-anhydrosorbitol and a small amount of 3,6-anhydrosorbitol, and then further dehydrated to obtain isosorbide. Liquid acid catalysts have high catalytic activity and good selectivity, but they also have inevitable disadvantages, such as easy corrosion of equipment, difficulty in product separation, non-reusability of catalysts, and difficulty in continuous production. Therefore, it is urgent to establish a continuous production process for isosorbide. Among them, the research and development of efficient and recyclable catalysts is the most critical technical issue. At present, the research on sorbitol dehydration reaction mainly focuses on the development of efficient solid acid catalysts, including heteropoly acids, polymers, acidic resins, molecular sieves, etc. Heteropoly acid catalysts have the advantages of easy acidity regulation, stronger acidity than general solid acids, and good catalytic effect, but the active components are easy to lose at high temperatures and the catalyst has poor stability. Although polymers have high activity and high selectivity, they also have the disadvantage of easy loss of active components. Acidic resin has high acid content and stable network structure, has good catalytic effect on sorbitol dehydration, high reuse rate, long life and other advantages. Molecular sieve has reversible cation exchange capacity and exchange selectivity, can adjust the molecular sieve pore size, crystal electric field and surface properties, can adjust adsorption and catalytic performance, and has high activity and selectivity. Therefore, acidic resin and molecular sieve solid acid catalyst have become one of the main development targets of scientific researchers.

[0004] CN109134485B discloses a method of preparing isosorbide by acid catalysis using 1,4-dehydrated sorbitol as a reaction raw material in the presence of a fatty ketone reagent. The method uses a strongly acidic cation exchange resin Amberlyst-15, Amberlyst-35, Amberlyst-70, a hydrogen-type zeolite molecular sieve H-ZSM-5, H-Beta, HY, a Keggin-type phosphotungstic acid or a silicon tungstic acid as a catalyst to prepare isosorbide, and the reaction yield is as high as 97%. The method has mild reaction conditions and a high yield, but the method uses 1,4-dehydrated sorbitol, an intermediate product of sorbitol one-step dehydration, as a raw material, which is expensive compared to sorbitol raw materials, and the sorbitol one-step dehydration product 1,4-sorbitol must be separated and purified, which prolongs the production process and increases the production cost.

[0005] In addition, in addition to the influence of the catalyst, the removal of the reaction product water and the reaction temperature are also key factors affecting the dehydration of sorbitol. In the reaction process of sorbitol dehydration to generate isosorbide, the byproduct water will be detrimental to the reaction and needs to be removed in time; and low reaction temperature will cause the catalyst to fail to reach the activation temperature, and the dehydration reaction cannot proceed, while too high a reaction temperature will easily carbonize the product and the yield will be low. How to remove the byproduct water in time and control the reaction temperature are also urgent problems to be solved in the reaction of sorbitol dehydration to generate isosorbide. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing isosorbide by dehydrating sorbitol, so as to solve the technical problems of easily corroded equipment, difficult product separation, non-reusable catalyst and difficulty in continuous production in the prior art of preparing isosorbide by dehydrating sorbitol using a liquid acid catalyst.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The invention provides a method for preparing isosorbide by dehydrating sorbitol, comprising: melting sorbitol, adding a solid acid catalyst and an azeotropic agent to prepare isosorbide;

[0009] The solid acid catalyst includes a supported sulfonated polystyrene-divinylbenzene catalyst or a supported sulfonated phenolic resin solid acid catalyst.

[0010] According to some embodiments of the present invention, the mass ratio of sorbitol to the solid acid catalyst is 1:(0.001-0.5).

[0011] According to some embodiments of the present invention, the mass ratio of sorbitol to the entrainer is 1:(0.1-1).

[0012] According to some embodiments of the present invention, the azeotropic agent includes at least one of a benzene component and a ketone component.

[0013] Water is generated in the process of preparing isosorbide by dehydration of sorbitol, and it is usually necessary to remove the water by vacuuming or by passing nitrogen. In the present invention, by adding an azeotropic agent including a benzene component and a ketone component, water can be removed in time, and the reaction temperature can be controlled by the boiling point of the azeotropic agent, and the structure of the catalyst will not be destroyed, so as to achieve the effect of accelerating the reaction speed and improving the product yield.

[0014] According to some embodiments of the present invention, the benzene component includes at least one of benzene, toluene, xylene and mesitylene.

[0015] According to some embodiments of the present invention, the ketone component includes at least one of cyclopentanone, methyl isobutyl ketone and methyl isopropyl ketone.

[0016] According to some embodiments of the present invention, the reaction temperature of the stirring reaction is 100-180° C., the reaction time is 0.5-6 h; and the stirring speed is 300-1500 r / min.

[0017] According to some embodiments of the present invention, the method for preparing the supported sulfonated polystyrene-divinylbenzene catalyst includes: using a silane coupling agent to hydrophobically modify the surface of the carrier, then in situ growing polystyrene-divinylbenzene on the modified carrier, and then sulfonating it to obtain the supported sulfonated polystyrene-divinylbenzene catalyst.

[0018] It should be noted that the in-situ growth of polystyrene-divinylbenzene on the modified carrier described in the present invention means that styrene first reacts chemically with the silanization agent on the surface of the carrier to be bonded to the surface of the carrier, and then undergoes surface polymerization reaction.

[0019] Divinylbenzene (also called divinylbenzene) acts as a crosslinking agent in polystyrene-divinylbenzene polymers. It can generate a three-dimensional resin by copolymerization with polystyrene. Compared with linear resins, it has better thermal stability and a certain degree of improvement in mechanical strength. In addition, the three-dimensional resin can produce more pore structures, which is beneficial to the improvement of catalytic performance.

[0020] In the present invention, a silane coupling agent is used to hydrophobize the surface of the carrier. On the one hand, the hydrophilic surface of the carrier can be hydrophobized, the growth amount of polystyrene on the surface of the carrier can be increased, and the selectivity of the catalyst can be improved. If the surface of the carrier is not hydrophobized, polystyrene is difficult to grow on its surface and is more likely to polymerize in the solution. On the other hand, the hydrophobicity of the catalyst surface is increased, which is conducive to the desorption of water generated after the reaction from the surface and the stability of the catalyst is increased.

[0021] According to some embodiments of the present invention, the carrier is an inorganic carrier, preferably at least one selected from SiO2, Al2O3, TiO2, and molecular sieves.

[0022] In the present invention, various common types of molecular sieves can be used as carriers, such as H-Beta molecular sieve, ZSM-5 molecular sieve, and the like.

[0023] According to some embodiments of the present invention, the carrier is a spherical carrier.

[0024] According to some embodiments of the present invention, the particle size of the carrier is 1 to 5 mm.

[0025] According to some embodiments of the present invention, the silane coupling agent includes at least one of trimethoxypropylsilane (PTMS), trimethoxy-n-octylsilane (OTMS), and trimethoxyhexadecylsilane (HTMS).

[0026] According to some embodiments of the present invention, the hydrophobic modification comprises: dispersing the carrier in a first solvent, adding the silane coupling agent at 40 to 80° C., and stirring to react to obtain the modified carrier;

[0027] According to some embodiments of the present invention, the first solvent includes a mixed solvent of aqueous ammonia, anhydrous ethanol and water.

[0028] According to some embodiments of the present invention, the concentration of the aqueous ammonia is 10 to 25 wt %.

[0029] According to some embodiments of the present invention, the mass ratio of the aqueous ammonia, anhydrous ethanol and water is 1:(1-5):(1-5).

[0030] According to some embodiments of the present invention, the stirring reaction comprises stirring at a rotation speed of 100 to 1000 r / min for 24 to 72 hours.

[0031] According to some embodiments of the present invention, the mass ratio of the carrier to the silane coupling agent is 1:(0.025-1).

[0032] According to some embodiments of the present invention, the mass ratio of the carrier to the first solvent is 1:(1.5-8).

[0033] According to some embodiments of the present invention, the in situ growth of polystyrene-divinylbenzene on a modified support includes: adding a support, styrene, divinylbenzene, an initiator and a pore-forming agent into a second solvent, first stirring at 40 to 60° C. for 30 to 120 minutes, then heating to 70 to 80° C. and maintaining for 2 to 6 hours; then heating to 90 to 95° C. and reacting for 2 to 10 hours to obtain a modified support for in situ growth of polystyrene-divinylbenzene.

[0034] According to some embodiments of the present invention, a polymerization inhibitor is further added to the second solvent.

[0035] In the present invention, adding a polymerization inhibitor can effectively prevent styrene from polymerizing in an aqueous solution, thereby allowing more styrene to polymerize on the surface of the carrier.

[0036] According to some embodiments of the invention, the inhibitor comprises a methylene blue solution.

[0037] According to some embodiments of the invention, the second solvent comprises water.

[0038] According to some embodiments of the invention, the initiator comprises dibenzoyl peroxide (BPO).

[0039] According to some embodiments of the invention, the pore former comprises n-heptane and / or toluene.

[0040] In the present invention, the addition of pore-forming agent can make the polystyrene-divinylbenzene grown in situ on the carrier have a pore structure. The presence of the pore structure can significantly increase the surface area and the number of active sites of the catalyst, thereby increasing the rate of the catalytic reaction.

[0041] In the present invention, n-heptane and toluene are used together as pore-forming agents, and the pore-forming effect is better than that of n-heptane or toluene alone. The volume ratio of n-heptane to toluene is preferably within the range of 1: (0.8-1.2).

[0042] According to some embodiments of the present invention, the molar ratio of styrene to divinylbenzene is 10:(1-10), the mass ratio of the sum of the masses of styrene and divinylbenzene to the modified carrier is 1:(2-20), the mass ratio of the sum of the masses of styrene and divinylbenzene to n-heptane is 1:(1-5), and the mass ratio of the sum of the masses of styrene and divinylbenzene to dibenzoyl peroxide is 1:(0.05-0.20).

[0043] According to some embodiments of the present invention, the mass ratio of the sum of the masses of styrene and divinylbenzene to the mass of the second solvent is 1:(8-10).

[0044] According to some embodiments of the present invention, the sulfonation treatment comprises dispersing a modified carrier of in-situ grown polystyrene-divinylbenzene in a third solvent, adding a sulfonating reagent and stirring the reaction for 2 to 8 hours to obtain the supported sulfonated polystyrene-divinylbenzene catalyst.

[0045] According to some embodiments of the present invention, the third solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene.

[0046] According to some embodiments of the present invention, the sulfonation reagent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide.

[0047] According to some embodiments of the present invention, the mass ratio of the modified support for in-situ growth of polystyrene-divinylbenzene to the sulfonation reagent is (30-40): (1-10).

[0048] According to some embodiments of the present invention, the mass ratio of the modified support for in-situ growth of polystyrene-divinylbenzene to the third solvent is (30-40): (50-80).

[0049] According to some embodiments of the present invention, the preparation method of the supported sulfonated phenolic resin solid acid catalyst comprises: using a silane coupling agent to hydrophobically modify the surface of a carrier to obtain a modified carrier; then using a soluble phenolic resin and a curing agent to polymerize in situ growth on the modified carrier to obtain a modified carrier loaded with phenolic resin; and then sulfonating the modified carrier loaded with phenolic resin to obtain the supported sulfonated phenolic resin solid acid catalyst.

[0050] The preparation method of the supported sulfonated phenolic resin solid acid catalyst provided by the present invention can effectively increase the dispersion and active surface area of ​​the resin by in-situ growing the phenolic resin on the surface of the carrier, thereby improving the catalytic activity of the sulfonated phenolic resin, and at the same time improving the utilization efficiency of the resin and reducing the catalyst cost.

[0051] It should be noted that the in-situ growth of polymerization on a modified carrier using a soluble phenolic resin and a curing agent described in the present invention means that the phenolic resin first reacts chemically with the silanization agent on the carrier surface to be bonded to the surface, and then a surface polymerization reaction occurs.

[0052] In the present invention, a silane coupling agent is used to hydrophobize the surface of the carrier. On the one hand, the hydrophilic surface of the carrier can be hydrophobized, the growth amount of the phenolic resin on the surface of the carrier can be increased, and the selectivity of the catalyst can be improved. If the surface of the carrier is not hydrophobized, the phenolic resin is difficult to grow on its surface and is more likely to polymerize in the solution. On the other hand, the hydrophobicity of the catalyst surface is increased, which is conducive to the desorption of water generated after the reaction from the surface and the stability of the catalyst is increased.

[0053] In the present invention, the soluble phenolic resin refers to a phenolic resin that is soluble in water or an organic solvent.

[0054] According to some embodiments of the present invention, the carrier is an inorganic carrier.

[0055] According to some embodiments of the present invention, the carrier is selected from at least one of SiO2, Al2O3, TiO2, and molecular sieves.

[0056] According to some embodiments of the present invention, the carrier is a spherical carrier.

[0057] According to some embodiments of the present invention, the particle size of the carrier is 1 to 5 mm.

[0058] According to some embodiments of the present invention, the silane coupling agent includes at least one of trimethoxypropylsilane (PTMS), trimethoxy-n-octylsilane (OTMS), and trimethoxyhexadecylsilane (HTMS).

[0059] According to some embodiments of the present invention, the curing agent includes hexamethylenetetramine

[0060] According to some embodiments of the present invention, the hydrophobic modification comprises: dispersing the carrier in a fourth solvent, adding the silane coupling agent at 40 to 80° C., and stirring to react to obtain the modified carrier;

[0061] According to some embodiments of the present invention, the fourth solvent includes a mixed solvent of aqueous ammonia, anhydrous ethanol and water.

[0062] According to some embodiments of the present invention, the concentration of the aqueous ammonia is 10 to 25 wt %.

[0063] According to some embodiments of the present invention, the mass ratio of the aqueous ammonia, anhydrous ethanol and water is 1:(1-5)::(1-5).

[0064] According to some embodiments of the present invention, the stirring reaction comprises stirring at a rotation speed of 100 to 1000 r / min for 24 to 72 hours.

[0065] According to some embodiments of the present invention, the mass ratio of the carrier to the silane coupling agent is 1:(0.025-1).

[0066] According to some embodiments of the present invention, the mass ratio of the carrier to the fourth solvent is 1:(1.5-8).

[0067] According to some embodiments of the present invention, the in-situ growth of polymerization on a modified carrier using a soluble phenolic resin and a curing agent includes: dissolving the soluble phenolic resin and the curing agent in a fifth solvent, adding the modified carrier, and reacting for 12-72 hours under a sealed condition of 80 to 200° C. to obtain a modified carrier loaded with phenolic resin. Wherein, the reaction temperature can be selected from, for example, 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 150° C., 160° C., 180° C., 200° C., etc., and the reaction time can be selected from 12h, 18h, 24h, 28h, 36h, 40h, 48h, 55h, 60h, 67h, 72h, etc.

[0068] According to some embodiments of the present invention, the fifth solvent includes at least one of methanol, ethanol, acetone and water.

[0069] According to some embodiments of the present invention, the mass ratio of the phenolic resin to the modified carrier is (0.05-0.50):1, preferably (0.1-0.5):1, more preferably (0.2-0.3):1, for example 0.3:1; the mass ratio of the phenolic resin to the curing agent is 10:(1-3); preferably 10:(1.5-2.5), for example 10:1.5.

[0070] According to some embodiments of the present invention, the mass ratio of the fifth solvent to the phenolic resin is (3-20):1, preferably (5-10):1.

[0071] According to some embodiments of the present invention, the sulfonation treatment comprises dispersing the modified carrier loaded with phenolic resin in a sixth solvent, adding a sulfonating reagent and stirring the reaction for 2 to 8 hours to obtain the loaded sulfonated phenolic resin solid acid catalyst.

[0072] According to some embodiments of the present invention, the sixth solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene.

[0073] According to some embodiments of the present invention, the sulfonation reagent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide.

[0074] According to some embodiments of the present invention, the mass ratio of the modified carrier loaded with phenolic resin to the sulfonated reagent is (30-40): (1-10).

[0075] According to some embodiments of the present invention, the mass ratio of the modified carrier loaded with phenolic resin to the sixth solvent is (30-40): (60-80).

[0076] The beneficial effects of the present invention are at least:

[0077] The method for preparing isosorbide by dehydrating sorbitol provided by the present invention has high sorbitol conversion rate and isosorbide yield, and compared with the existing isosorbide preparation industrial technology, greatly reduces the generation of byproducts such as water, improves the isosorbide yield, and overcomes the disadvantages of using liquid acid catalysts, such as easy corrosion of equipment, difficulty in continuous production, difficulty in product separation, and non-reusability of catalysts, so that continuous production can be carried out. DETAILED DESCRIPTION

[0078] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent in detail and do not limit the scope of protection of the present invention in any way.

[0079] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the reagent amounts, unless otherwise specified, are the reagent amounts used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0080] Preparation Example 1

[0081] Supported sulfonated polystyrene-divinylbenzene catalyst A-01

[0082] 70g of a mixed solvent of ammonia water (25wt%), anhydrous ethanol and double distilled water (mass ratio of 1:2:2) was added to a three-necked flask and stirred in a 60℃ constant temperature water bath for 60min. 25g of Al2O3 round balls with a particle size of 3mm were weighed and slowly added to the three-necked flask and continued to stir for 5min. Then, 5g of trimethoxy-n-octylsilane was added and continued to stir at 500r / min for 72h. After the reaction was completed, the solid balls obtained by filtration were washed with anhydrous ethanol and double distilled water and dried to obtain a modified carrier. Add the modified carrier to a three-necked flask, and then add styrene, divinylbenzene, n-heptane, distilled water, 3-5 drops of methylene blue solution, and dibenzoyl peroxide (BPO) initiator in proportion, wherein the mass ratio of (styrene + divinylbenzene) / modified carrier is 0.1:1, the molar ratio of styrene / divinylbenzene is 2:1, the mass ratio of n-heptane / (styrene + divinylbenzene) is 3:1, the mass ratio of distilled water / (styrene + divinylbenzene) is 10:1, and the mass ratio of dibenzoyl peroxide / (styrene + divinylbenzene) is 0.1:1. Stir in a 60°C constant temperature water bath for 120 minutes. Heat to 70°C under reflux conditions and keep for 2 hours, then heat to 90°C and react for 2 hours. After the reaction is completed, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water and dried to obtain a modified carrier of in-situ growth polystyrene-divinylbenzene. At room temperature, the modified carrier of in-situ grown polystyrene-divinylbenzene was added to a three-necked flask, the content of the modified carrier of in-situ grown polystyrene-divinylbenzene was 35%, the content of dichloroethane was 60%, and the content of chlorosulfonic acid was 5%, and the reaction was stirred for 4 hours. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then dried to obtain catalyst A-01. Catalyst A-01 is a spherical particle with complete particles and uniform size; it has good strength and is not easy to crush.

[0083] Preparation Example 2

[0084] Supported sulfonated polystyrene-divinylbenzene catalyst A-02

[0085] The preparation method of catalyst A-02 refers to that of Preparation Example 1, except that 25 g of Al2O3 spherical pellets with a particle size of 3 mm are replaced with 25 g of SiO2 spherical pellets with a particle size of 3 mm.

[0086] Preparation Example 3

[0087] Supported sulfonated polystyrene-divinylbenzene catalyst A-03

[0088] The preparation method of catalyst A-03 refers to that of Preparation Example 1, except that 25 g of 3 mm Al2O3 spherical pellets are replaced with 25 g of 3 mm TiO2 spherical pellets.

[0089] Preparation Example 4

[0090] Supported sulfonated polystyrene-divinylbenzene catalyst A-04

[0091] The preparation method of catalyst A-04 refers to that of Preparation Example 1, except that 25 g of Al2O3 spherical pellets with a particle size of 3 mm are replaced with 25 g of H-Beta spherical pellets with a particle size of 3 mm.

[0092] Preparation Example 5

[0093] Supported sulfonated polystyrene-divinylbenzene catalyst A-05

[0094] The preparation method of catalyst A-05 refers to Preparation Example 1, except that n-heptane is replaced by a mixture of toluene and n-heptane of equal mass, and the mass ratio of toluene to n-heptane in the mixture is 1:1.

[0095] Preparation Example 6

[0096] Supported sulfonated polystyrene-divinylbenzene catalyst A-06

[0097] The preparation method of catalyst A-06 refers to Preparation Example 1, except that n-heptane is replaced with an equal mass of toluene.

[0098] Preparation Example 7

[0099] Supported sulfonated polystyrene-divinylbenzene catalyst A-07

[0100] The preparation method of catalyst A-07 is similar to that of Preparation Example 1, except that no methylene blue solution is added.

[0101] Comparative Preparation Example 1

[0102] Add Al2O3 spherical beads with a particle size of 3mm into a three-necked flask, and then add styrene, divinylbenzene, n-heptane, distilled water, 3-5 drops of methylene blue solution, and dibenzoyl peroxide (BPO) initiator in proportion, wherein the mass ratio of (styrene + divinylbenzene) / Al2O3 spherical beads is 0.1:1, the molar ratio of styrene / divinylbenzene is 2:1, the mass ratio of n-heptane / (styrene + divinylbenzene) is 3:1, the mass ratio of distilled water / (styrene + divinylbenzene) is 10:1, and the mass ratio of dibenzoyl peroxide / (styrene + divinylbenzene) is 0.1:1. Stir in a 60℃ constant temperature water bath for 120min. Heat to 70℃ under reflux conditions and keep for 2h, then heat to 90℃ and react for 2h. After the reaction is completed, the filtered solid beads are washed with anhydrous ethanol and double distilled water and dried to obtain Al2O3 spherical beads with surface growth resin. At room temperature, the Al2O3 spherical beads of the surface-grown resin were added into a three-necked flask, the content of the Al2O3 spherical beads of the surface-grown resin was 35%, the content of dichloroethane was 60%, and the content of chlorosulfonic acid was 5%, and the reaction was stirred for 4 hours. After the reaction was completed, the solid beads obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then dried to obtain catalyst D-01.

[0103] Comparative Preparation Example 2

[0104] In a three-necked flask, add styrene, divinylbenzene, n-heptane, distilled water, 3-5 drops of methylene blue solution, and dibenzoyl peroxide (BPO) initiator in proportion, wherein the molar ratio of styrene / divinylbenzene is 2:1, the mass ratio of n-heptane / (styrene + divinylbenzene) is 3:1, the mass ratio of distilled water / (styrene + divinylbenzene) is 10:1, and the mass ratio of dibenzoyl peroxide / (styrene + divinylbenzene) is 0.1:1. Stir in a 60°C constant temperature water bath for 120 min. Raise the temperature to 70°C under reflux conditions and maintain for 2 hours, then raise the temperature to 90°C and react for 2 hours. After the reaction is completed, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water and dried to obtain polystyrene resin pellets.

[0105] At room temperature, polystyrene resin beads were added to a three-necked flask, the content of polystyrene resin beads was 15%, the content of dichloroethane was 70%, and the content of chlorosulfonic acid was 15%, and the reaction was stirred for 4 hours. After the reaction, the solid beads obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then dried to obtain a carrier-free sulfonated polystyrene resin catalyst D-02. The particles of catalyst D-02 were uneven in size and various in shape; and the strength was poor and it was easily crushed.

[0106] Preparation Example 8

[0107] Supported sulfonated phenolic resin solid acid catalyst B-01~B-03

[0108] Add a mixed solvent of 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a constant temperature water bath at 40°C for 10 min. Weigh 10 g of spherical SiO2 (particle size 3 mm) or spherical Al2O3 (particle size 3 mm) or spherical TiO2 (particle size 3 mm) respectively, slowly add them into the three-necked flask and continue stirring for 5 min. Then, add 1 g of trimethoxyhexadecylsilane and continue stirring at 800 r / min for 24 h. After the reaction is completed, wash the filtered solid with anhydrous ethanol and double distilled water, and dry it to obtain a surface-modified carrier.

[0109] Under stirring conditions, 2 g of soluble phenolic resin (2123) and 0.4 g of hexamethylenetetramine curing agent were dissolved in 40 mL of ethanol to obtain a clear solution, which was transferred to a hydrothermal kettle, and then 10 g of the modified inorganic carrier was added, and the reaction was sealed at 100 ° C for 48 hours. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water and dried to obtain pellets with surface-grown resin.

[0110] At room temperature, 10g of beads after different modified support growth resins were added to a three-necked flask, and 20g of dichloroethane was added to swell for 15min, and then 2mL of chlorosulfonic acid was added and stirred for 4h. After the reaction, the solid beads obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80°C to obtain SiO2-supported sulfonated phenolic resin solid acid catalyst B-01, Al2O3-supported sulfonated phenolic resin solid acid catalyst B-02, and TiO2-supported sulfonated phenolic resin solid acid catalyst B-03.

[0111] Preparation Example 9

[0112] Supported sulfonated phenolic resin solid acid catalyst B-04~B-07

[0113] A mixed solvent of 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water was added to a three-necked flask and stirred in a 40°C constant temperature water bath for 10 min. 10 g of spherical Al2O3 (particle size 2 mm) was weighed and slowly added to the three-necked flask and continued to stir for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and continued to stir at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0114] Under stirring conditions, 1g (B-04), 2g (B-05), 3g (B-06) and 5g (B-07) of soluble phenolic resin (2123) and 20% of the mass of the phenolic resin hexamethylenetetramine curing agent were dissolved in 20mL of ethanol to obtain clear solutions. The solutions with different phenolic concentrations were transferred to a hydrothermal kettle, and then 10g of the modified spherical Al2O3 carrier was added, and the mixture was sealed at 100°C for polymerization reaction for 24h. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with surface growth of resin.

[0115] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, and 20 g of dichloroethane was added to swell for 15 min, and then 1 mL, 2 mL, 3 mL and 5 mL of chlorosulfonic acid were added, respectively, and stirred for 4 h. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain sulfonated phenolic resin solid acid catalysts B-04 to B-07 with different phenolic resin loadings.

[0116] Preparation Example 10

[0117] Supported sulfonated phenolic resin solid acid catalyst B-08~B-12

[0118] A mixed solvent of 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water was added to a three-necked flask and stirred in a 40°C constant temperature water bath for 10 min. 10 g of spherical Al2O3 (particle size 2 mm) was weighed and slowly added to the three-necked flask and continued to stir for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and continued to stir at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0119] Under stirring conditions, 3g of soluble phenolic resin (2123) and 10% (B-08), 15% (B-09), 20% (B-10), 25% (B-11) and 30% (B-12) of hexamethylenetetramine curing agent of phenolic resin mass were dissolved in 20mL of ethanol to obtain a clear solution, and the solutions with different solid agent addition amounts were transferred to a hydrothermal autoclave, and then 10g of the modified spherical Al2O3 carrier was added, and the reaction was sealed at 100°C for polymerization for 24h. After the reaction was completed, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with surface growth of resin.

[0120] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 3 mL of chlorosulfonic acid was added to stir and react for 4 h. After the reaction, the solid pellet obtained by filtration was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain loaded sulfonated phenolic resin solid acid catalysts B-08 to B-12 with different curing agent / phenolic resin ratios.

[0121] Comparative Preparation Example 3

[0122] Sulfonated phenolic resin D-03 without carrier

[0123] Under stirring conditions, 3 g of soluble phenolic resin (2123) and 0.45 g of hexamethylenetetramine curing agent were dissolved in 50 mL of ethanol to obtain a clear solution, which was transferred to a hydrothermal autoclave and sealed for polymerization at 120 ° C for 24 hours. After the reaction, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a polymerized powdered phenolic resin.

[0124] At room temperature, 10 g of the prepared resin was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 10 mL of chlorosulfonic acid was added and stirred for 4 h. After the reaction, the filtered solid was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain sulfonated phenolic resin powder catalyst D-03.

[0125] Example 1

[0126] Weigh 50g of sorbitol into a three-necked flask and slowly heat it. After the sorbitol melts, add 0.05g of catalyst A-01 and 5g of benzene as an azeotropic agent. At a reaction temperature of 100°C and a stirring speed of 1500r / min, react for 0.5h, then take samples for analysis. The test results are shown in Table 1.

[0127] Example 2

[0128] Weigh 50g of sorbitol into a three-necked flask and slowly heat it. After the sorbitol melts, add 5g of catalyst A-01 and 50g of mesitylene as an azeotropic agent. At a reaction temperature of 170°C and a stirring speed of 300r / min, react for 5h, then take samples for analysis. The test results are shown in Table 1.

[0129] Example 3

[0130] Weigh 50g of sorbitol into a three-necked flask and slowly heat it. After the sorbitol melts, add 0.5g of catalyst A-01 and 20g of cyclopentanone as an azeotropic agent. At a reaction temperature of 130°C and a stirring speed of 800r / min, react for 2h, then take samples for analysis. The test results are shown in Table 1.

[0131] Example 4

[0132] The test method is the same as that of Example 3, except that 20 g of cyclopentanone is replaced by 20 g of toluene. The test results are shown in Table 1.

[0133] Embodiments 5 to 10

[0134] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of catalysts A-02 to A-07. The test results are shown in Table 1.

[0135] Examples 11 to 22

[0136] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of catalysts B-01 to B-12. The test results are shown in Table 1.

[0137] Comparative Example 1

[0138] The test method is the same as that of Example 3, except that 20 g of cyclopentanone is not added. The test results are shown in Table 1.

[0139] Comparative Example 2

[0140] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of concentrated sulfuric acid (98 wt%). The test results are shown in Table 1.

[0141] Comparative Example 3

[0142] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of catalyst D-01. The test results are shown in Table 1.

[0143] Comparative Example 4

[0144] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of catalyst D-02. The test results are shown in Table 1.

[0145] Comparative Example 5

[0146] The test method is the same as that of Example 3, except that 0.5 g of catalyst A-01 is replaced by 0.5 g of catalyst D-03. The test results are shown in Table 1.

[0147] Table 1 Reaction results of different catalysts to generate isosorbide

[0148]

[0149] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for preparing isosorbide by dehydrating sorbitol, characterized in that: include: After sorbitol is melted, a solid acid catalyst and an azeotropic agent are added, and the mixture is stirred for reaction to obtain isosorbide; The solid acid catalyst includes a supported sulfonated polystyrene-divinylbenzene catalyst or a supported sulfonated phenolic resin solid acid catalyst.

2. The method according to claim 1, characterized in that The mass ratio of sorbitol to solid acid catalyst is 1:(0.001-0.5); And / or, the mass ratio of sorbitol to the entrainer is 1:(0.1-1).

3. The method according to claim 1 or 2, characterized in that: The azeotropic agent includes at least one of a benzene component and a ketone component; Preferably, The benzene component includes at least one of benzene, toluene, xylene and mesitylene; And / or, the ketone component includes at least one of cyclopentanone, methyl isobutyl ketone and methyl isopropyl ketone.

4. The method according to any one of claims 1 to 3, characterized in that: The reaction temperature of the stirring reaction is 100-180° C., the reaction time is 0.5-6 hours, and the stirring speed is 300-1500 r / min.

5. The method according to any one of claims 1 to 4, characterized in that: The preparation method of the supported sulfonated polystyrene-divinylbenzene catalyst comprises: using a silane coupling agent to hydrophobically modify the surface of a carrier, then in-situ growing polystyrene-divinylbenzene on the modified carrier, and then performing a sulfonation treatment to obtain the supported sulfonated polystyrene-divinylbenzene catalyst; Preferably, The carrier is an inorganic carrier, preferably at least one selected from SiO2, Al2O3, TiO2, and molecular sieve; And / or, the carrier is a spherical carrier; And / or, the particle size of the carrier is 1 to 5 mm; And / or, the silane coupling agent includes at least one of trimethoxypropylsilane, trimethoxy-n-octylsilane, and trimethoxy-hexadecylsilane; And / or, the hydrophobic modification comprises: dispersing the carrier in a first solvent, adding the silane coupling agent at 40-80° C., stirring and reacting to obtain the modified carrier; preferably, the first solvent comprises a mixed solvent of ammonia water, anhydrous ethanol and water; And / or, the mass ratio of the carrier to the silane coupling agent is 1:(0.025-1).

6. The method according to claim 5, characterized in that The in-situ growth of polystyrene-divinylbenzene on the modified carrier comprises: adding the carrier, styrene, divinylbenzene, an initiator and a pore-forming agent into a second solvent, stirring at 40-60° C. for 30-120 min, then heating to 70-80° C. and maintaining for 2-6 h; then heating to 90-95° C. and reacting for 2-10 h to obtain a modified carrier for in-situ growth of polystyrene-divinylbenzene; Preferably, A polymerization inhibitor is also added to the second solvent; preferably, the polymerization inhibitor comprises a methylene blue solution; and / or, the second solvent comprises water; and / or, the initiator comprises dibenzoyl peroxide; and / or, the pore-forming agent comprises n-heptane and / or toluene; And / or, the molar ratio of styrene to divinylbenzene is 10:(1-10), the mass ratio of the sum of the mass of styrene and divinylbenzene to the modified carrier is 1:(2-20), the mass ratio of the sum of the mass of styrene and divinylbenzene to n-heptane is 1:(1-5), and the mass ratio of the sum of the mass of styrene and divinylbenzene to dibenzoyl peroxide is 1:(0.05-0.20); And / or, the mass ratio of the sum of the masses of styrene and divinylbenzene to the mass of the second solvent is 1:(8-10).

7. The method according to claim 5 or 6, characterized in that: The sulfonation treatment comprises dispersing the modified carrier of in-situ grown polystyrene-divinylbenzene in a third solvent, adding a sulfonation reagent and stirring the reaction for 2 to 8 hours to obtain the supported sulfonated polystyrene-divinylbenzene catalyst; Preferably, The third solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene; And / or, the sulfonating agent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide; and / or, the mass ratio of the modified support of the in-situ grown polystyrene-divinylbenzene to the sulfonated reagent is (30-40): (1-10); And / or, the mass ratio of the modified carrier for in-situ growth of polystyrene-divinylbenzene to the third solvent is (30-40): (50-80).

8. The method according to any one of claims 1 to 4, characterized in that: The preparation method of the supported sulfonated phenolic resin solid acid catalyst comprises: using a silane coupling agent to hydrophobically modify the surface of a carrier to obtain a modified carrier; then using a soluble phenolic resin and a curing agent to polymerize and grow in situ on the modified carrier to obtain a modified carrier loaded with phenolic resin; and then sulfonating the modified carrier loaded with phenolic resin to obtain the supported sulfonated phenolic resin solid acid catalyst; Preferably, The carrier is an inorganic carrier, preferably at least one selected from SiO2, Al2O3, TiO2, and molecular sieve; And / or, the carrier is a spherical carrier; And / or, the particle size of the carrier is 1 to 5 mm; And / or, the silane coupling agent includes at least one of trimethoxypropylsilane, trimethoxy-n-octylsilane, and trimethoxy-hexadecylsilane; and / or, the curing agent comprises hexamethylenetetramine; And / or, the hydrophobic modification comprises: dispersing the carrier in a fourth solvent, adding the silane coupling agent at 40-80° C., stirring and reacting to obtain the modified carrier; preferably, the fourth solvent comprises a mixed solvent of ammonia water, anhydrous ethanol and water; And / or, the mass ratio of the carrier to the silane coupling agent is 1:(0.025-1).

9. The method according to claim 8, characterized in that The in-situ growth of the soluble phenolic resin and the curing agent on the modified carrier includes: dissolving the soluble phenolic resin and the curing agent in a fifth solvent, adding the modified carrier, and reacting for 12-72 hours under a sealed condition of 80-200° C. to obtain a modified carrier loaded with the phenolic resin; Preferably, The fifth solvent includes at least one of methanol, ethanol, acetone and water; And / or, the mass ratio of the phenolic resin to the modified carrier is (0.05-0.50):1, and the mass ratio of the phenolic resin to the curing agent is 10:(1-3); And / or, the mass ratio of the fifth solvent to the phenolic resin is (3-20):

1.

10. The method according to claim 8 or 9, characterized in that: The sulfonation treatment comprises dispersing the modified carrier loaded with phenolic resin in a sixth solvent, adding a sulfonation reagent and stirring the reaction for 2 to 8 hours to obtain the loaded sulfonated phenolic resin solid acid catalyst; Preferably, The sixth solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene; And / or, the sulfonating agent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide; And / or, the mass ratio of the modified carrier loaded with phenolic resin to the sulfonated reagent is (30-40): (1-10); And / or, the mass ratio of the modified carrier loaded with phenolic resin to the sixth solvent is (30-40):(60-80).

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