Acidic resin, method of preparation and use thereof, and method of preparation of isosorbide

Abstract

This invention discloses an acidic resin, a method for preparing the same and its use, and a catalytic method for preparing isosorbide. The copolymer in the acidic resin comprises a first structural unit derived from styrene having an electron-withdrawing group at the meta position of a benzene ring, a second structural unit derived from divinylbenzene, and formula 1: [Formula 1] It contains a third structural unit derived from an allyl sulfonic acid compound represented by TIFF2026515615000016.tif31168.

Description

[Technical Field]

[0001] The present invention relates to acidic resins, methods for preparing and using the same, and catalytic methods for preparing isosorbide. [Background technology]

[0002] As fossil fuels are depleted and environmental pollution worsens, biomass is renewable, abundant, highly functional, and environmentally friendly. Therefore, the development and utilization of biomass raw materials and derivatives are attracting significant attention in the fields of fine chemicals and new materials. Isosorbide, an important biomass-derived chemical, is a completely non-toxic and environmentally friendly diol, and is widely used not only in pharmaceuticals, surfactants, and plastic additives, but also in novel polymer materials. For example, isosorbide has excellent antihypertensive and diuretic properties and can be used to synthesize the surfactants Span and Tween. It can also be used to synthesize novel green plasticizers as an alternative to benzoic acid diester plasticizers. Furthermore, it can be used to modify PET to significantly improve its high-temperature properties and impact resistance, and in new carbonate material technologies, it can be used as a substitute raw material for bisphenol A, which poses health risks, and can improve the environmental performance of polycarbonates. For these reasons, isosorbide synthesis technology has attracted considerable attention in recent years.

[0003] Currently, isosorbide synthesis primarily uses sorbitol or cellulose as raw materials and solid or liquid acids as catalysts. Liquid acids mainly include concentrated sulfuric acid, benzenesulfonic acid, and ionic liquids, while solid acids mainly include molecular sieves, acidic resins, metal oxides, metal phosphates, and heteropoly acids. Isosorbide is synthesized using a batch process. While batch processes have the advantages of low capital investment and suitability for small-scale production, they have the disadvantages of unstable product quality and difficulty in automation, making them unsuitable for large-scale industrial production. Considering the performance advantages of isosorbide and its applications in new materials fields, market demand for isosorbide is likely to increase rapidly, thus necessitating the development of a continuous process for preparing isosorbide.

[0004] Reports on continuous processes for producing isosorbide already exist. U.S. Patent No. 6,864,378 employs a continuous production process for isosorbide in which a liquid acid catalyst is used, and the resulting product forms an azeotrope with water vapor and is separated by distillation. Chinese Patent Application Publication No. 104788465 employs a continuous production process for isosorbide using a two-stage dehydration process, but does not mention the type of catalyst used, and the separation of the product requires deacidification and desalting steps. Chinese Utility Model No. 204752581 discloses a continuous production apparatus for producing isosorbide from sorbitol. U.S. Patent No. 6,639,067 discloses a continuous production process for isosorbide in which an organic solvent is used as a water carrier, and the product and the solvent are distilled and then the product is separated, and the solvent is reusable. Chinese Patent Application Publication No. 103980286 discloses a continuous process for producing isosorbide in which the catalyst is a liquid acid.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] The continuous processes described in the aforementioned literature all utilize liquid acids, requiring neutralization and deacidification in subsequent separation, as well as subsequent desalting operations, thus increasing process and production costs. In contrast, solid acid dehydration catalysts have advantages such as relatively easy product separation and the ability to reuse the catalyst. However, solid acid catalysts have challenges in catalyst lifetime and selectivity at high temperatures. In the catalytic dehydration synthesis of isosorbide, a strongly acidic resin that shows good conversion rate and selectivity is used as a solid acid catalyst. However, the catalyst lifetime is limited, and especially when the reaction temperature exceeds 120°C, the sulfonic acid group is easily removed, and the acidity decreases significantly. Therefore, it is not possible to meet the requirements for continuous isosorbide production, resulting in high production costs for isosorbide, unstable product quality, and limited industrial applications. Furthermore, since the raw material hexitol contains multiple active hydroxyl groups, multiple dehydration reaction pathways occur under the action of the catalyst. The primary dehydration products include 1,4-dehydrated products, 1,5-dehydrated products, and 2,5-dehydrated products, but only the 1,4-dehydrated product undergoes a secondary dehydration reaction to produce isosorbide.

[0007] Therefore, it is desirable to provide a novel catalyst system that improves product selectivity, suppresses by-product formation, has long-term stability, and satisfies the requirements of continuous processes. [Means for solving the problem]

[0008] (Content of the invention) Existing strongly acidic resin catalysts have limited lifespans and cannot meet the requirements of continuous isosorbide production processes. As a result, the cost of isosorbide production is high, and the quality of the product is unstable. Furthermore, conventional catalysts have the problem of low selectivity for isosorbide and low isosorbide yield, making it impossible to simultaneously achieve high catalyst stability, high isosorbide yield, and high selectivity. The present invention provides an acidic resin, a method for preparing the acidic resin, the use of the acidic resin as a catalyst for isosorbide production, and a continuous method for preparing isosorbide. When used as a catalyst in the synthesis reaction of isosorbide, the acidic resin of the present invention exhibits excellent catalytic performance and stability, especially at high temperatures. In particular, when the acidic resin of the present invention is used as a catalyst in the synthesis reaction of isosorbide in combination with other solid acid catalysts, not only high catalytic stability but also high isosorbide yield and selectivity can be obtained. The acidic resin of the present invention is extremely suitable as a catalyst for continuous isosorbide production, thereby reducing production costs and improving the stability of product quality.

[0009] A first aspect of the present invention is to provide an acidic resin, wherein the copolymer in the acidic resin comprises a first structural unit derived from styrene having an electron-withdrawing group at the meta position of a benzene ring, a second structural unit derived from divinylbenzene, and a copolymer of formula 1: [ka] The first structural unit comprises a third structural unit derived from an allyl sulfonic acid compound represented by the formula, where R1, R2, and R3 are each independently hydrogen or C1-C2 alkyl (i.e., methyl or ethyl), M is H or a metallic element, and a portion of the benzene ring in the first structural unit has a -SO3H group.

[0010] In some preferred embodiments of the present invention, the copolymer in the acidic resin comprises a first structural unit represented by formula 2, a second structural unit represented by formula 3, and a third structural unit represented by formula 4. [ka] Here, in formula 2, Y is -SO3H, X is an electron-withdrawing group, and in formula 4, R1, R2, and R3 are each independently hydrogen or a C1-C2 alkyl group.

[0011] In the present invention, the acidic resin acts as a catalyst, exhibiting excellent catalytic performance and high-temperature stability in the synthesis reaction of isosorbide. In particular, when the acidic resin catalyst is used in combination with a solid acid catalyst (different from the acidic resin catalyst of the present invention) in the synthesis reaction of isosorbide, the acidic resin of the present invention exhibits high catalytic stability, as well as high isosorbide yield and high selectivity.

[0012] According to the present invention, the electron-withdrawing group can be selected from a wide range of options. In some preferred embodiments of the present invention, the electron-withdrawing group may be at least one of a halogen atom, a nitro group, a nitroso group, a C1-C4 alkoxy group, and a C1-C4 alkanoyloxy group (e.g., an acetoxy group). The halogen atom may be selected from fluorine, chlorine, bromine, and iodine, for example, fluorine and chlorine.

[0013] According to the present invention, when M is a metallic element, the metallic element may be selected from alkali metals and alkaline earth metals, for example, one or more of lithium, sodium, potassium, magnesium, calcium, strontium, and barium. In some embodiments, M may be lithium, sodium, or potassium.

[0014] According to the present invention, the content of each structural unit in the copolymer can be selected from a wide range. In some embodiments of the present invention, when the total weight of the copolymer is 100% by weight, the content of the first structural unit may be 1 to 50% by weight, the content of the second structural unit may be 30 to 90% by weight, and the content of the third structural unit may be 1 to 50% by weight.

[0015] Preferably, in the present invention, when the total weight of the copolymer is 100% by weight, the content of the first structural unit is 15 to 40% by weight, for example, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, and can be within the range consisting of any two values. The content of the second structural unit can be 30 to 70% by weight, for example, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, and can be within the range consisting of any two values. The content of the third structural unit can be 10 to 45% by weight, for example, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, and can be within the range consisting of any two values.

[0016] In some embodiments of the present invention, the specific surface area of the acidic resin is 200 to 600 m -1 ·g -1 , preferably 200 to 500 m 2 ·g -1 It can be. For example, the specific surface area of the acidic resin is 200 m 2 ·g -1 , 250 m 2 ·g -1 , 300 m 2 ·g -1 , 350 m 2 ·g -1 , 400 m 2 ·g -1 , 450 m 2 ·g -1 , 500 m 2 ·g -1 , 550 m 2 ·g -1 , or 600 m 2 ·g -1 , and can be within the range consisting of any two values.

[0017] In some embodiments of the present invention, the pore volume of the acidic resin is 0.2 to 0.8 cm 3 ·g -1 , preferably 0.2 to 0.7 cm 3 ·g -1 It can be. For example, the pore volume of the acidic resin is 0.2 cm3 ·g -1 , 0.25cm 3 ·g -1 , 0.3cm 3 ·g -1 , 0.35cm 3 ·g -1 , 0.4cm 3 ·g -1 , 0.45cm 3 ·g -1 , 0.5cm 3 ·g -1 , 0.55cm 3 ·g -1 , 0.6cm 3 ·g -1 , 0.65cm 3 ·g -1 , 0.7cm 3 ·g -1 , 0.75cm 3 ·g -1 , 0.8cm 3 ·g -1 , and can be within a range of any two values.

[0018] In some embodiments of the present invention, the pore size of the acidic resin may be 1 to 20 nm, preferably 5 to 20 nm. For example, the pore size of the acidic resin may be within the range of 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, and any two values.

[0019] In the present invention, the pore volume, pore diameter, and specific surface area of ​​the acidic resin are measured by a nitrogen adsorption / desorption method based on GB / T19587-2017.

[0020] In some embodiments of the present invention, the acid content of the acidic resin is 1 to 10 mmol·g. -1 Preferably 3-8 mmol·g -1 For example, the acid content of the acidic resin is 1 mmol·g. -1 , 2 mmol·g -1 , 3 mmol·g -13.5 mmol·g -1 , 4mmol·g -1 4.5 mmol·g -1 , 5 mmol·g -1 5.5 mmol·g -1 , 6 mmol·g -1 6.5 mmol·g -1 , 7mmol·g -1 7.5 mmol·g -1 , 8mmol·g -1 , 9mmol·g -1 , 10 mmol·g -1 , and can be within a range of any two values.

[0021] In the present invention, the acid content of the acidic resin is measured by acid-base neutralization titration, with reference to GB / T2895-2008.

[0022] In the present invention, the particle size of the acidic resin is not particularly limited, and any particle size generally known in the art can be used. In some embodiments, the particle size of the acidic resin may be 0.02 to 5 mm, for example, 0.1 to 2 mm.

[0023] The acidic resin of the present invention can be used as a catalyst, for example, in reactions that utilize an acidic resin as a catalyst. In one preferred embodiment, the acidic resin of the present invention is used as a catalyst for preparing isosorbide from hexitol. In a particularly preferred embodiment, the acidic resin of the present invention is used as a catalyst for preparing isosorbide from the dehydration reaction of 1,4-sorbitan.

[0024] A second aspect of the present invention is a method for preparing the acidic resin described in the first aspect, comprising the following steps: A step of copolymerizing divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, and an allyl sulfonic acid compound represented by formula 1 in the presence of a dispersant and an initiator to obtain a resin matrix; [ka] (wherein R1, R2, and R3 are each independently hydrogen or C1-C2 alkyl, and M is H or a metallic element.); and The step of sulfonating the resin matrix to obtain an acidic resin, This provides a method that includes [something].

[0025] In some preferred embodiments of the present invention, the preparation method involves the following steps: (1) A step of mixing a solution containing the dispersant with a mixed solution containing divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, an allyl sulfonic acid compound of formula 1, and the initiator, and carrying out a polymerization reaction to obtain a resin matrix; (2) The step of mixing the resin matrix with an organic solvent containing a pore-expanding agent to obtain a mixed solution containing the resin matrix; and (3) A step of obtaining an acidic resin by bringing the mixed solution containing the resin matrix into contact with a sulfonating agent to perform sulfonation, and optionally washing and / or drying the solution. Includes.

[0026] According to the present invention, the electron-withdrawing group and M are as described in the first embodiment.

[0027] According to the present invention, the amounts of divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, and the allyl sulfonic acid compound of formula 1 (i.e., monomers used in copolymerization) can be selected from a wide range. In some embodiments of the present invention, when the total weight of the copolymer is 100% by weight, the content of the first structural unit may be 1 to 50% by weight, the content of the second structural unit may be 30 to 90% by weight, and the content of the third structural unit may be 1 to 50% by weight.

[0028] Preferably, in the present invention, when the total weight of all monomers used to prepare the copolymer is 100% by weight, the content of styrene having an electron-withdrawing group at the meta position of the benzene ring may be in the range of 15 to 40% by weight, for example, 15%, 20%, 25%, 30%, 35%, 40%, and any two values; the content of divinylbenzene may be in the range of 30 to 70% by weight, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, and any two values; and the content of the allyl sulfonic acid compound of formula 1 may be in the range of 10 to 45% by weight, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and any two values.

[0029] In the present invention, copolymerization of divinylbenzene, styrene having an electron-withdrawing group at the meta position of the phenyl ring, and an allyl sulfonic acid compound of formula 1 (also called a comonomer) can be carried out using a method commonly used for copolymerization of styrene and divinylbenzene, such as free radical suspension polymerization. Free radical suspension copolymerization of styrene and divinylbenzene is known in the art. In one preferred embodiment, the copolymerization of the present invention is free radical suspension polymerization. The copolymerization step of the present invention can use the same or similar polymerization processes and conditions as those used for free radical suspension copolymerization of styrene and divinylbenzene.

[0030] According to the present invention, the dispersant can be selected from a wide range of options. According to the present invention, a dispersant that is generally known in the art may be used in the reaction of step (1). In some preferred embodiments of the present invention, the dispersant is selected from at least one of polyvinyl alcohol, hydroxyethyl cellulose, and mixtures thereof, and is preferably polyvinyl alcohol having a number average molecular weight of 50,000 to 100,000.

[0031] According to the present invention, the initiator can be selected from a wide range of options. According to the present invention, various initiators commonly used in the art to initiate polymerization of monomers having vinyl functional groups can be used. For example, initiators commonly used in free radical suspension polymerization can be used. Such initiators are known in the art. In some preferred embodiments of the present invention, the initiator may be an azo compound initiator and / or a peroxide initiator, preferably comprising at least one of benzoyl peroxide, phenylacetyl peroxide, potassium peroxide, and azobisisobutyronitrile.

[0032] According to the present invention, the pore-expanding agent can be selected from a wide range of options. According to the present invention, in step (2), a pore-expanding agent commonly known in the art may be used. In some preferred embodiments of the present invention, the pore-expanding agent may be at least one of dichloromethane, dichloroethane, n-heptane, and mixtures thereof.

[0033] According to the present invention, the amounts of the dispersant, the initiator, and the pore-expanding agent can be selected from a wide range of options.

[0034] According to the present invention, as long as polymerization is initiated and a resin matrix is ​​obtained, those skilled in the art can easily select the amount of initiator used. In some preferred embodiments of the present invention, the amount of initiator used may be 0.2 to 6 parts by mass, preferably 0.5 to 4 parts by mass, per 100 parts by mass of the total monomer.

[0035] According to the present invention, those skilled in the art can easily select the amount of the dispersant used. In some preferred embodiments of the present invention, the amount of the dispersant used may be 1 to 10 parts by mass per 100 parts by mass of the total monomer.

[0036] According to the present invention, the amount of the pore-expanding agent can be selected from a wide range. In some preferred embodiments of the present invention, the amount of the pore-expanding agent may be 2 to 40 parts by mass, preferably 2 to 30 parts by mass, per 100 parts by mass of the resin matrix.

[0037] According to the present invention, the conditions for the polymerization reaction can be selected from a wide range. According to the present invention, various commonly used polymerization conditions can be used for polymerization or copolymerization in step (1), for example, polymerization conditions commonly used in the art to initiate polymerization of monomers having vinyl functional groups, such as free radical suspension polymerization, can be used. In some preferred embodiments of the present invention, the conditions for the polymerization reaction in step (1) may be a temperature of 60 to 150°C and / or a time of 3 to 14 hours. For example, the polymerization temperature may be within the range of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, or 160°C and any two values. For example, the polymerization time may be within the range of 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours and any two values.

[0038] According to the present invention, in step (2), the mixing conditions of the resin matrix and the organic solvent containing the pore-expanding agent can be selected from a wide range. In some preferred embodiments of the present invention, mixing the resin matrix and the organic solvent containing the pore-expanding agent in step (2) may include raising the temperature of the mixed system to 30 to 100°C, preferably 40 to 100°C, at a rate of 0.1 to 3°C / min. For example, the heating rate may be within the range of 0.1°C / min, 0.2°C / min, 0.3°C / min, 0.4°C / min, 0.5°C / min, 0.6°C / min, 0.7°C / min, 0.8°C / min, 0.9°C / min, 1.0°C / min, 1.1°C / min, 1.2°C / min, 1.3°C / min, 1.4°C / min, 1.5°C / min, 1.6°C / min, 1.7°C / min, 1.8°C / min, 1.9°C / min, 2.0°C / min, 2.1°C / min, 2.2°C / min, 2.3°C / min, 2.4°C / min, 2.5°C / min, 2.6°C / min, 2.7°C / min, 2.8°C / min, 2.9°C / min, 3.0°C / min, and any two values. For example, the temperature can rise to a range consisting of 30°C, 40°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 90°C, 100°C, and any two values.

[0039] The sulfonation of the resin matrix is ​​known in the art. The sulfonation step of the present invention can be carried out using conditions that are generally known in the art with respect to the sulfonation of polystyrene resins.

[0040] According to the present invention, the sulfonation conditions in step (3) can be selected from a wide range. In some preferred embodiments of the present invention, the sulfonation conditions in step (3) may include a temperature of 30 to 100°C and / or a time of 5 to 20 hours. For example, the sulfonation temperature may be in the range of 30°C, 40°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 90°C, 100°C, and any two values. For example, the sulfonation time may be in the range of 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, and any two values.

[0041] According to the present invention, the sulfonating agent can be a strong acid, such as an acid commonly used in the art for sulfonating polystyrene resins. The type of strong acid can be selected from a wide range of options. In some preferred embodiments of the present invention, the strong acid can be selected from at least one of concentrated sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, methanesulfonic acid, and mixtures thereof.

[0042] After sulfonation, the resulting sulfonated product (sulfonated resin matrix) may be post-treated to obtain the acidic resin of the present invention. Post-treatment includes immersion in a solvent, washing, filtration, and / or drying. These post-treatment operations are known in the art.

[0043] As an example, in one embodiment, the acidic resin of the present invention may be prepared by the following method: First, the dispersant and water are added to the reactor, stirred, and gradually heated until dissolved to form a continuous phase. Next, predetermined amounts of styrene, divinylbenzene, and an allyl sulfonic acid compound represented by formula 1, each having an electron-withdrawing group at the meta position, are mixed, and a predetermined amount of initiator is added. The resulting mixture is added to the continuous phase. The resulting system is then stirred and heated for 5 to 10 hours to ensure that the polymerization of the monomers is completed. The system is then cooled to room temperature, filtered, washed, dried, and sieved to obtain a mesoporous resin. The prepared mesoporous resin is weighed and added to the reactor along with the solvent and pore-expanding agent. The temperature is gradually increased, and a strong acid is added dropwise to carry out the sulfonation reaction. After the addition is complete, the reaction is continued for 7 to 12 hours. After the reaction is complete, the resin is cooled to room temperature, filtered, and separated. The product is immersed in the solvent, washed, filtered, and dried to a constant weight to obtain an acidic resin. The acidic resin of the present invention is prepared by synthesizing a mesoporous granular resin by suspension copolymerization using substituted styrene, divinylbenzene, and monomers containing sulfonic acid groups as raw materials, with a radical initiator such as an organic peroxide as an initiator and a dispersant, and then sulfonating this mesoporous granular resin.

[0044] In some embodiments of the present invention, only divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, and allyl sulfonic acid compounds of formula 1 are used as comonomers for preparing acidic resins.

[0045] A third aspect of the present invention provides the use of an acidic resin as described in the first aspect, or an acidic resin prepared by the preparation method described in the second aspect, as a catalyst in the preparation of isosorbide.

[0046] In some preferred embodiments, the acidic resin of the present invention may not be used alone as a catalyst for preparing isosorbide. That is, the acidic resin of the present invention may be used in combination with other types of catalysts as a catalyst for preparing isosorbide.

[0047] A fourth aspect of the present invention is a method for preparing isosorbide, preferably a continuous preparation method, comprising the following steps: 1) A step of contacting hexitol with a solid acid catalyst to carry out a primary dehydration reaction and obtain a primary dehydration reaction product mixture; and 2) Remove the solid acid catalyst from the primary dehydration reaction mixture, and contact the resulting mixture (i.e., the mixture obtained after removing the solid acid catalyst from the primary dehydration reaction mixture) with the acidic resin of the present invention to carry out a secondary dehydration reaction to obtain a reaction product containing isosorbide. The objective is to provide a method comprising, wherein the acidic resin is an acidic resin prepared by the acidic resin described in the first embodiment and / or the preparation method described in the second embodiment.

[0048] The method for preparing isosorbide according to the present invention can use hexitol as a raw material. The preparation method according to the present invention is suitable for preparing isosorbide in a continuous process using a highly selective catalyst, i.e., the acidic resin of the present invention, as a catalyst.

[0049] In the preparation method of the present invention, a supply unit, a reaction unit, and a product purification unit may be provided. The reaction unit comprises two reactors, with the first reactor preparing a 1,4-dehydrated product and the second reactor preparing isosorbide. In the two-stage reactor, different catalysts can be used depending on the purpose of the reaction. The catalyst in the first reactor is a solid acid catalyst suitable for the production of 1,4-sorbitan, and the acidic resin of the present invention is used as a catalyst suitable for the production of isosorbide in the second reactor, thereby enabling the continuous and efficient production of isosorbide.

[0050] In this invention, the acidic resin of the present invention is used as a catalyst in combination with a solid acid catalyst, and isosorbide is produced in high yield and with high selectivity by carrying out a secondary dehydration reaction. Furthermore, the entire preparation method of the present invention is catalytically stable and allows for continuous production.

[0051] According to the present invention, hexitol can be selected from a wide range of sources. In some preferred embodiments of the present invention, hexitol is selected from sorbitol and / or mannitol. In the present invention, hexitol can be used in the form of solid hexitol and / or aqueous hexitol solutions. In some embodiments, the concentration of the aqueous hexitol solution can be 50 to 90% by weight. For example, the concentration of the aqueous hexitol solution can be in the range of 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, 90% by weight, and any two of these values.

[0052] According to the present invention, the solid acid catalyst can be selected from a wide range of options. In a preferred embodiment, the solid acid catalyst is different from the acidic resin of the present invention. The solid acid catalyst may also be a catalyst known in the art for the preparation of isosorbide. In some preferred embodiments of the present invention, the solid acid catalyst may be selected from at least one of molecular sieves, acidic resins different from the acidic resin of the present invention, metal phosphates, Lewis acids, and heteropoly acids, preferably at least one of heteropoly acids and acidic resins different from the acidic resin of the present invention, more preferably heteropoly acids, and even more preferably phosphotungstic solid acid catalysts.

[0053] The inventors have discovered through research that, in a method for preparing isosorbide according to the present invention, using a phosphotungstic acid solid acid catalyst in the primary dehydration reaction and the acidic resin catalyst of the present invention in the secondary dehydration reaction unexpectedly yields particularly beneficial results, including high yield and selectivity, as well as high catalyst stability. It is believed that the phosphotungstic acid solid acid catalyst and the acidic resin catalyst of the present invention exhibit a synergistic effect in the two-step dehydration reaction of the present invention.

[0054] According to the present invention, in the primary dehydration reaction, the mass ratio of the solid acid catalyst to hexitol can be selected from a wide range. In some preferred embodiments of the present invention, in the primary dehydration reaction, the mass ratio of the solid acid catalyst to hexitol may be (0.1~1.0):100, preferably (0.5~6):100, and more preferably (1~5):100. In the present invention, the mass ratio of the solid acid catalyst to hexitol is calculated using the mass of hexitol before the primary dehydration reaction.

[0055] In preferred embodiments of the present invention, the selectivity of 1,4-sorbitan in the primary dehydration reaction is greater than 80%, preferably 85% or more, and more preferably 90% or more. In these preferred embodiments, isosorbide exhibits higher yield and selectivity.

[0056] According to the present invention, in the secondary dehydration reaction, the mass ratio of the acidic resin catalyst to hexitol can be selected from a wide range. In some preferred embodiments of the present invention, in the secondary dehydration reaction, the mass ratio of the acidic resin catalyst to hexitol may be (1-10):100, preferably (2-6):100. In the present invention, the mass ratio of the acidic resin catalyst to hexitol is calculated using the mass of hexitol before the primary dehydration reaction.

[0057] In one preferred embodiment of the present invention, the yield of isosorbide prepared by the secondary dehydration reaction is 79% or more, preferably more than 80%.

[0058] According to the present invention, the conditions in step 1) (primary dehydration reaction) can be selected from a wide range. In some preferred embodiments of the present invention, the conditions in step 1) include a reaction temperature of 80 to 130°C and / or a time (e.g., residence time) of 3 to 7 hours and / or a reaction pressure of 0.001 to 1 atm. For example, the reaction temperature may be within the range of 80°C, 90°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, and any two values. For example, the reaction time may be within the range of 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, and any two values. As will be understood by those skilled in the art, if the method of the present invention is a continuous process, the reaction time may be the residence time. For example, the reaction pressure may be within the range of 0.001 atm, 0.005 atm, 0.01 atm, 0.02 atm, 0.03 atm, 0.04 atm, 0.05 atm, 0.06 atm, 0.07 atm, 0.08 atm, 0.09 atm, 0.1 atm, 0.2 atm, 0.3 atm, 0.4 atm, 0.5 atm, 0.6 atm, 0.7 atm, 0.8 atm, 0.9 atm, 1 atm, and any two values.

[0059] According to the present invention, the conditions in step 2) (secondary dehydration reaction) can be selected from a wide range. In some preferred embodiments of the present invention, the conditions in step 2) include a reaction temperature of 120 to 160°C and / or a residence time of 1 to 9 hours and / or a reaction pressure of 0.001 to 1 atm. For example, the reaction temperature may be within the range of 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, and any two values. For example, the reaction time may be within the range of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, and any two values. As will be understood by those skilled in the art, if the method of the present invention is a continuous process, the reaction time may be the residence time. For example, the reaction pressure may be within the range of 0.001 atm, 0.005 atm, 0.01 atm, 0.02 atm, 0.03 atm, 0.04 atm, 0.05 atm, 0.06 atm, 0.07 atm, 0.08 atm, 0.09 atm, 0.1 atm, 0.2 atm, 0.3 atm, 0.4 atm, 0.5 atm, 0.6 atm, 0.7 atm, 0.8 atm, 0.9 atm, 1 atm, and any two values.

[0060] In some preferred embodiments of the present invention, the water produced in the primary dehydration reaction is discharged from the top of the reactor during the reaction, the solid acid catalyst is removed from the primary dehydration reaction product mixture after discharge from the reactor, and this mixture is then introduced into the reactor for the secondary dehydration reaction to carry out the reaction. For example, the solid acid catalyst can be removed by filtration. In some embodiments, the primary dehydration reaction product mixture can be dehydrated before the secondary dehydration reaction. The dehydrated primary reaction product mixture is then introduced into the reactor for the secondary reaction to carry out the reaction.

[0061] In some preferred embodiments of the present invention, the preparation method further comprises separating and / or purifying the reaction product containing isosorbide obtained after the secondary dehydration reaction to obtain purified isosorbide.

[0062] According to the present invention, the separation and / or purification method can employ separation and / or purification methods commonly used in the art. In some preferred embodiments of the present invention, the separation and / or purification method may be distillation and / or crystallization. Those skilled in the art can easily select the conditions for distillation and / or crystallization. For example, distillation can be carried out at a distillation temperature of about 160°C and a vacuum of about 0.005 atm, followed by crystallization at room temperature in a mixed solvent of isopropyl alcohol and n-hexane, preferably with a mass ratio of isopropyl alcohol to n-hexane of (10-20):1.

[0063] According to the present invention, the method for preparing isosorbide may be a batch method or a continuous method, but a continuous method is preferred.

[0064] As an example, in one embodiment, the method for the continuous preparation of isosorbide according to the present invention may be carried out as follows: The reaction raw materials are hexitol and / or an aqueous solution of hexitol (if hexitol is used, the reaction raw materials are added to a preheating tower and heated until good fluidity is obtained), and the raw materials are introduced into a first reaction stirring tank equipped with a solid acid catalyst. The reaction temperature is 80-130°C, the residence time is 3-7 hours, the reaction pressure is 0.0001-1 atm, and the amount of solid acid catalyst added is 1-10% by weight relative to the mass of the reaction raw materials (hexitol). After the reaction is carried out for a certain period of time, the obtained product is sent to a dehydration tower through a reactor valve filter, and at the same time, the reaction raw materials are supplied at a constant rate. The filtered product is optionally dehydrated in a dehydration tower and then sent to a second reaction stirring tank for further dehydration. The acidic resin of the present invention is loaded into the second reactor as a catalyst. The reaction temperature is 120-160°C, the residence time is 1-9 hours, the reaction pressure is 0.0001-1 atm, and the amount of catalyst added is 1-10% by weight relative to the mass of the reaction raw materials. After the reaction has been carried out for a certain period of time, the reaction mixture is introduced into a separation system, where the catalyst is removed by filtration. The resulting product mixture is then purified by distillation and crystallization, and dried to obtain the product. Optionally, preferably, a portion of the separated liquid can be recycled. The catalyst is recyclable after filtration and drying, thereby enabling continuous operation of the entire system.

[0065] The acidic resin of the present invention exhibits excellent catalytic performance and high-temperature stability when used as a catalyst in the synthesis reaction of isosorbide. In particular, combining the acidic resin catalyst with a solid acid catalyst for isosorbide synthesis not only provides high catalytic stability but also increases the yield and selectivity of isosorbide, making it very suitable for continuous production. As a result, it is possible to reduce production costs and improve the stability of product quality.

[0066] This invention uses substituted styrene having an electron-withdrawing group at the meta position of the benzene ring, divinylbenzene, and a sulfonic acid group-containing monomer represented by formula 1 as raw materials. A free radical initiator such as an organic peroxide is added as an initiator, and a dispersant is added to synthesize a mesoporous granular resin by suspension copolymerization. The prepared resin is then sulfonated to obtain a resin with high temperature resistance and strong acidity. The sulfonic acid groups in the acidic resin of this invention have high thermal stability, thus extending the high-temperature lifetime of the catalyst. Furthermore, by controlling the preparation conditions, the pore structure and specific surface area of ​​the catalyst become favorable for the dehydration reaction, further improving the selectivity. Therefore, by synthesizing isosorbide in combination with the acidic resin catalyst of this invention and a solid acid catalyst, excellent catalytic performance and high-temperature stability are observed, making it suitable for continuous production, and enabling reduction of production costs and improvement of the stability of product quality. The isosorbide prepared by this invention can be widely used in the fields of new materials, pharmaceuticals, and organic synthesis.

[0067] In this invention, isosorbide can be prepared in high yield and with high selectivity by using a specific acidic resin catalyst and solid acid catalyst according to the present invention, and by employing a secondary dehydration reaction. Furthermore, the preparation method of this invention is catalytically stable, enabling continuous production.

[0068] (Specific forms for carrying out the invention) Examples The present invention will be described in detail below with reference to specific examples. However, it should be noted that the following examples are for further explanation of the present invention and do not limit the scope of protection of the present invention. Non-essential improvements and modifications made by those skilled in the art based on this disclosure are also included in the scope of protection of the present invention. Phosphateungstic acid (solid acid catalyst) was analytically pure and purchased from Aladdin Reagent Co., Ltd. The polyvinyl alcohol used was analytically pure, and we used polyvinyl alcohol 1788 purchased from Aladdin Reagent Co., Ltd. The acid content of the acidic resin was measured by acid-base neutralization titration, referring to GB / T2895-2008. The pore volume, pore diameter, and specific surface area of ​​the acidic resin were measured using the nitrogen adsorption / desorption method according to GB / T19587-2017. Pore ​​volume, pore diameter, and specific surface area were measured using a Micromeritics ASAP 2420 specific surface area and pore distribution analyzer. Liquid chromatography analysis was performed using an Agilent 1100 high-performance liquid chromatograph. Unless otherwise specified, all raw materials used in this invention are conventional commercially available products. The raw materials used in the following examples were treated in accordance with methods well known in the industry before use, as necessary, to meet the reaction conditions. For example, styrene and divinylbenzene were distilled before use to remove polymerization inhibitors.

[0069] Example 1 of preparation of acidic resin Two grams of polyvinyl alcohol were weighed and added to a three-necked flask, and 500 ml of water was added. The mixture was heated to a boil and stirred to completely dissolve the polyvinyl alcohol, forming a continuous phase. The mixture was then cooled to 65°C. 30 g of metasubstituted chlorostyrene, 60 g of divinylbenzene, and 20 g of sodium allyl sulfonate were weighed in a predetermined ratio, and 3 g of benzoyl peroxide was weighed and uniformly dissolved in a beaker to prepare the dispersed phase. This dispersed phase was added to a three-necked flask containing the continuous phase and heated to 90°C with stirring for 7 hours to completely react with the monomers and complete the polymerization reaction. After cooling the polymerization system to room temperature (25°C), it was filtered and separated, washed with deionized water to a pH of 5-7, dried at 100-120°C, and particles in the range of 10-100 mesh were collected and weighed using a stainless steel sieve to obtain a mesoporous resin. 40 g of mesoporous resin was weighed and added to the reactor. 45 g of toluene solvent and 8 g of ethylene dichloride as a pore-expanding agent were added. The temperature was raised to 65°C at a rate of 1.6°C / min. Then, 50 g of concentrated sulfuric acid (98% by mass) was added dropwise. After the addition was complete, the reaction was continued for 10 hours. After the reaction was complete, the system was cooled to room temperature and filtered. The product was immersed in isopropyl alcohol for 10 hours, washed with water, and filtered. The product was washed with deionized water until neutral, filtered, and dried at 100-120°C until a constant weight was obtained to obtain acidic resin.

[0070] Example 2 of Acidic Resin Preparation Two grams of polyvinyl alcohol were weighed and added to a three-necked flask, and 500 ml of water was added. The mixture was heated to a boil and stirred to completely dissolve the polyvinyl alcohol, forming a continuous phase. The mixture was then cooled to 65°C. 30 g of metasubstituted chlorostyrene, 60 g of divinylbenzene, and 20 g of sodium methylallyl sulfonate were weighed in the specified ratio, and 3 g of benzoyl peroxide was weighed and uniformly dissolved in a beaker to prepare the dispersed phase. This dispersed phase was added to a three-necked flask containing the continuous phase and heated to 90°C with stirring for 7 hours to completely react with the monomers and complete the polymerization reaction. After cooling the polymerization system to room temperature, it was filtered and separated, washed with deionized water to a pH of 5-7, dried at 100-120°C, and particles in the range of 10-100 mesh were collected and weighed using a stainless steel sieve to obtain a mesoporous resin. 40 g of mesoporous resin was weighed and added to the reactor. 50 g of toluene solvent and 10 g of ethylene dichloride as a pore-expanding agent were added. The temperature was raised to 65°C at a rate of 1.5°C / min. Then, 50 g of concentrated sulfuric acid (98% by mass) was added dropwise. After the addition was complete, the reaction was continued for 10 hours. After the reaction was complete, the system was cooled to room temperature and filtered. The product was immersed in isopropyl alcohol for 10 hours, washed with water, and filtered. The product was washed with deionized water until neutral, filtered, and dried at 100-120°C until a constant weight was obtained to obtain acidic resin.

[0071] Preparation Example of Acidic Resin 3 3 g of polyvinyl alcohol was weighed and added to a three-necked flask, and 500 mL of water was added. The mixture was heated to a boil and stirred to completely dissolve the polyvinyl alcohol, forming a continuous phase. The mixture was then cooled to 65°C. 30 g of metasubstituted chlorostyrene, 60 g of divinylbenzene, and 40 g of sodium allyl sulfonate were weighed in a predetermined ratio, and 3 g of potassium persulfate was weighed and uniformly dissolved in a beaker to prepare the dispersed phase. This dispersed phase was added to a three-necked flask containing the continuous phase and heated to 90°C with stirring for 7 hours to completely react with the monomers and complete the polymerization reaction. After cooling the polymerization system to room temperature, it was filtered and separated, washed with deionized water to a pH of 5-7, dried at 100-120°C, and particles in the range of 10-100 mesh were collected and weighed using a stainless steel sieve to obtain a mesoporous resin. 40 g of mesoporous resin was weighed and added to the reactor. 60 g of toluene solvent and 10 g of ethylene dichloride as a pore-expanding agent were added. The temperature was raised to 65°C at a rate of 1.6°C / min. Then, 30 g of concentrated sulfuric acid (98% by mass) was added dropwise. After the addition was complete, the reaction was continued for 10 hours. After the reaction was complete, the system was cooled to room temperature and filtered. The product was immersed in isopropyl alcohol for 10 hours, washed with water, and filtered. The product was washed with deionized water until neutral, filtered, and dried at 100-120°C until a constant weight was obtained to obtain acidic resin.

[0072] Preparation Example of Acidic Resin 4 3 g of polyvinyl alcohol was weighed and added to a three-necked flask, and 500 mL of water was added. The mixture was heated to a boil and stirred to completely dissolve the polyvinyl alcohol, forming a continuous phase. The mixture was then cooled to 65°C. 25 g of meta-substituted acetoxystyrene, 50 g of divinylbenzene, and 40 g of sodium methylallyl sulfonate were weighed in a predetermined ratio, and 3 g of potassium persulfate was weighed and uniformly dissolved in a beaker to prepare the dispersed phase. This dispersed phase was added to a three-necked flask containing the continuous phase and heated to 90°C with stirring for 7 hours to completely react with the monomers and complete the polymerization reaction. After cooling the polymerization system to room temperature, it was filtered and separated, washed with deionized water to a pH of 5-7, dried at 100-120°C, and particles in the range of 10-100 mesh were collected and weighed using a stainless steel sieve to obtain a mesoporous resin. 40 g of mesoporous resin was weighed and added to the reactor. 50 g of toluene solvent and 10 g of ethylene dichloride as a pore-expanding agent were added. The temperature was raised to 65°C at a rate of 1.5°C / min. Then, 30 g of fuming sulfuric acid (98% by mass) was added dropwise. After the addition was complete, the reaction was continued for 10 hours. After the reaction was complete, the system was cooled to room temperature and filtered. The product was immersed in isopropyl alcohol for 10 hours, washed with water, and filtered. The product was washed with deionized water until neutral, filtered, and dried at 100-120°C until a constant weight was obtained to obtain acidic resin.

[0073] Comparative Acidic Resin Preparation Example 1 3 g of polyvinyl alcohol was weighed and added to a three-necked flask, and 500 mL of water was added. The mixture was heated to a boil and stirred to completely dissolve the polyvinyl alcohol, forming a continuous phase. The mixture was then cooled to 65°C. 37 g of styrene and 63 g of divinylbenzene were weighed in a predetermined ratio, and 3 g of benzoyl peroxide was weighed and uniformly dissolved in a beaker to prepare the dispersed phase. This dispersed phase was added to a three-necked flask containing the continuous phase and heated to 90°C with stirring for 7 hours to completely react with the monomers and complete the polymerization reaction. After cooling the polymerization system to room temperature, it was filtered and separated, washed with deionized water to a pH of 5-7, dried at 100-120°C, and particles in the range of 10-100 mesh were collected and weighed using a stainless steel sieve to obtain a mesoporous resin. 25 g of mesoporous resin was weighed and added to the reactor. 22 g of xylene solvent and 14 g of ethylene dichloride as a pore-expanding agent were added. The temperature was raised to 60°C at a rate of 1.5°C / min. Then, 150 mL of concentrated sulfuric acid (98% by mass) was added dropwise. After the addition was complete, the reaction was continued for 10 hours. After the reaction was complete, the system was cooled to room temperature and filtered. The product was immersed in isopropyl alcohol for 10 hours, washed with water, and filtered. The product was washed with deionized water until neutral, filtered, and dried at 100-120°C until a constant weight was obtained to obtain comparative acidic resin 1.

[0074] Comparative Acid Resin Preparation Example 2 A comparative acidic resin was prepared in accordance with the method of Acidic Resin Preparation Example 3, except that equimolar amounts of styrene monomer were used instead of metasubstituted chlorostyrene, to obtain comparative acidic resin 2.

[0075] Comparative Acidic Resin Preparation Example 3 Except for using an equimolar amount of metasubstituted chlorostyrene instead of styrene monomer, A comparative acidic resin was prepared according to the method of Comparative Acidic Resin Preparation Example 1, and comparative acidic resin 3 was obtained.

[0076] Isosorbide Synthesis Example 1 100 g of a 70% sorbitol aqueous solution was pumped into the primary dehydration reactor. Simultaneously, a solid acid catalyst (phosphotungstic solid acid) equivalent to 5% of the sorbitol mass was added as a catalyst for the primary dehydration reaction. The system was heated to 110°C, stirred, and then the pressure was reduced to a vacuum of 0.1 atm. The water produced during the reaction was discharged from the top of the reactor via a condenser. After 4 hours of reaction, liquid chromatography analysis showed a selectivity of 95% for 1,4-sorbitan. The valve was opened, and a 70% sorbitol aqueous solution was pumped into the reactor. Simultaneously, the reaction mixture was passed through a filter at the bottom of the reactor to remove the catalyst. The resulting filtrate was supplied to the secondary dehydration reactor. An acidic resin equivalent to 3% of the sorbitol mass (Acidic Resin Preparation Example 1) was introduced into the secondary dehydration reactor. The reaction was carried out at a temperature of 130°C and a pressure of 0.06 atm for 5 hours. Analysis by liquid chromatography showed that the yield of isosorbide produced by the secondary dehydration reaction was 81.5%. The valve was opened to discharge the reaction solution, and the catalyst was removed and recovered by filtration. The resulting mixture was purified by distillation (distillation temperature 160°C, vacuum 0.005 atm) and crystallization (crystallization solvent was a mixed solvent of isopropanol and n-hexane, with a mass ratio of 12:1 between the two solvents). The crystallization temperature was 20°C. The product was dried to obtain the isosorbide product.

[0077] Isosorbide Synthesis Example 2 100 g of a 75% sorbitol aqueous solution was pumped into the primary dehydration reactor. Simultaneously, a solid acid catalyst (phosphotungstic solid acid) equivalent to 3% of the sorbitol mass was added as a catalyst for the primary dehydration reaction. The system was heated to 120°C, stirred, and then the pressure was reduced to a vacuum of 0.15 atm. The water produced during the reaction was discharged from the top of the reactor via a condenser. After 5 hours of reaction, liquid chromatography analysis showed a selectivity of 93% for 1,4-sorbitan. The valve was opened, and a 75% sorbitol aqueous solution was pumped into the reactor. Simultaneously, the reaction mixture was passed through a filter at the bottom of the reactor to remove the catalyst. The resulting filtrate was supplied to the secondary dehydration reactor. An acidic resin equivalent to 3.5% of the sorbitol mass (Acidic Resin Preparation Example 2) was introduced into the secondary dehydration reactor. The reaction was carried out at a temperature of 135°C and a pressure of 0.1 atm for 5 hours. Analysis by liquid chromatography showed that the yield of isosorbide produced by the secondary dehydration reaction was 82.4%. The reaction solution was discharged by opening the valve, and the catalyst was removed and recovered by filtration. The resulting mixture was purified by distillation (distillation temperature 160°C, vacuum 0.005 atm) and crystallization (crystallization solvent was a mixed solvent of isopropanol and n-hexane, with a mass ratio of 15:1 between the two solvents). The crystallization temperature was 20°C. The product was dried to obtain the isosorbide product.

[0078] Isosorbide Synthesis Example 3 100 g of a 65% sorbitol aqueous solution was pumped into the primary dehydration reactor. Simultaneously, a solid acid catalyst (phosphotungstic solid acid) equivalent to 1% of the sorbitol mass was added as a catalyst for the primary dehydration reaction. The system was heated to 125°C, stirred, and then the pressure was reduced to a vacuum of 0.06 atm. The water produced during the reaction was discharged from the top of the reactor via a condenser. After 5 hours of reaction, liquid chromatography analysis showed a selectivity of 94% for 1,4-sorbitan. The valve was opened, and a 65% sorbitol aqueous solution was pumped into the reactor. Simultaneously, the reaction mixture was passed through a filter at the bottom of the reactor to remove the catalyst. The resulting filtrate was supplied to the secondary dehydration reactor. An acidic resin catalyst equivalent to 5% of the sorbitol mass (Acidic Resin Preparation Example 3) was introduced into the secondary dehydration reactor. The reaction was carried out at a temperature of 140°C and a pressure of 0.2 atm for 3 hours. Analysis by liquid chromatography showed that the yield of isosorbide produced by the secondary dehydration reaction was 80.9%. The reaction solution was discharged by opening the valve, and the catalyst was removed and recovered by filtration. The resulting mixture was purified by distillation (distillation temperature 160°C, vacuum 0.005 atm) and crystallization (crystallization solvent was a mixed solvent of isopropanol and n-hexane, with a mass ratio of 17:1 between the two solvents). The crystallization temperature was 20°C. The product was dried to obtain the isosorbide product.

[0079] Isosorbide Synthesis Example 4 Isosorbide was synthesized in accordance with the method of Isosorbide Synthesis Example 1, except that the acidic resin prepared in Acidic Resin Preparation Example 4 was used instead of the acidic resin prepared in Acidic Resin Preparation Example 1.

[0080] Isosorbide Synthesis Comparative Example 1 Isosorbide was synthesized in accordance with the method of Isosorbide Synthesis Example 1, except that the comparative acidic resin prepared in Comparative Acidic Resin Preparation Example 1 was used instead of the acidic resin prepared in Acidic Resin Preparation Example 1.

[0081] Isosorbide Synthesis Comparative Example 2 Isosorbide was synthesized according to the method of Isosorbide Synthesis Example 1, except that a phosphotungstic acid solid acid catalyst was used in the primary dehydration reactor instead of the acidic resin prepared in Acidic Resin Preparation Example 1. The isosorbide yield was 48.5%.

[0082] Isosorbide Synthesis Comparative Example 3 Isosorbide was synthesized according to the method of Isosorbide Synthesis Example 1, except that the comparative acidic resin prepared in Comparative Acidic Resin Preparation Example 2 was used instead of the acidic resin catalyst 1 prepared in Acidic Resin Preparation Example 1. The isosorbide yield was 79.6%. After 10 cycles, the isosorbide yield was 68.1%.

[0083] Isosorbide Synthesis Comparative Example 4 Isosorbide was synthesized according to the method of Isosorbide Synthesis Example 1, except that the comparative acidic resin prepared in Comparative Acidic Resin Preparation Example 3 was used instead of the acidic resin catalyst 1 prepared in Acidic Resin Preparation Example 1. The isosorbide yield was 80.5%. After 10 cycles, the isosorbide yield was 65.3%.

[0084] The specific surface area, pore volume, pore diameter, and acid content of the acidic resins prepared in the above example are shown in the table below: TIFF2026515615000005.tif117168

[0085] Method for calculating selectivity and yield Selectivity and yield were measured by high-performance liquid chromatography and calculated using the following method.

[0086] Method for calculating the selectivity of 1,4-sorbitan in the primary dehydration reaction:

number

[0087] Method for calculating the selectivity of isosorbide in a secondary dehydration reaction:

number

[0088] The formula for calculating the yield of isosorbide is as follows:

number

[0089] Table 1 shows the purity and yield of the isosorbide products obtained in the isosorbide synthesis example and the isosorbide synthesis comparative example.

[0090] [Table 1]

[0091] Stability test of acidic resins as catalysts Ten batches of isosorbide were prepared using acidic resin catalysts recovered from Isosorbide Synthesis Examples 1-4 and Isosorbide Synthesis Comparative Example 1, according to the respective examples and comparative examples. The purity and yield of the final batch of isosorbide are shown in Table 2. The acid content of the acidic resin recovered from the final batch was measured, and the results are shown in Table 3.

[0092] [Table 2]

[0093] [Table 3]

[0094] [Table 4]

[0095] The results from Tables 1 to 4 above show that the acidic resin catalyst of the present invention exhibits excellent catalytic performance and high-temperature stability in the synthesis reaction of isosorbide. By combining the acidic resin of the present invention with a solid acid catalyst in isosorbide synthesis, not only is high catalytic stability obtained, but also high isosorbide yield and selectivity.

[0096] The above examples are for illustrative purposes only and do not limit the present invention. While the present invention has been described with reference to representative examples, it should be understood that the terminology used herein is descriptive and interpretive, not restrictive. The present invention may be modified within the scope of the claims and may be altered without departing from the scope and spirit of the invention. The present invention as described herein relates to specific methods, materials, and examples, but this does not mean that the present invention is limited to the specific examples disclosed herein. Rather, the present invention can be extended to all other methods and applications having similar functions.

[0097] All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used herein have the meanings that are commonly understood by those skilled in the art. In the event of any conflict in definitions, the definitions herein shall prevail.

[0098] In this specification, when using the prefixes “well known to those skilled in the art,” “prior art,” or similar terms to describe materials, substances, methods, steps, devices, or components, the subject matter described by these prefixes includes not only those commonly used in the art at the time of filing, but also those that are not currently commonly used but are generally recognized in the art as suitable for similar purposes.

[0099] The endpoints and any values ​​of the ranges disclosed in this application should be understood not to be limited to exact ranges or values, but to include values ​​close to these ranges or values. For numerical ranges, one or more new numerical ranges can be obtained by combining the endpoint values ​​of each range, the endpoint values ​​of each range with other point values, and separate point values, and these numerical ranges are deemed to be specifically disclosed in the specification. Hereafter, as a general rule, new technical solutions can be obtained by combining each technical solution, and these are also deemed to be specifically disclosed in this specification.

[0100] In the context of this specification, unless explicitly stated otherwise, any matters or items not mentioned can be applied directly to matters or items known in the art without modification.

[0101] Furthermore, any embodiment described herein may be freely combined with one or more other embodiments described herein, and any technical solution or technical idea formed thereby shall be deemed part of the original disclosure or original record of the present invention and shall not be considered novel content not disclosed or foreseen herein unless such combination is clearly unreasonable to a person skilled in the art.

Claims

1. An acidic resin, wherein the copolymer in the acidic resin comprises a first structural unit derived from styrene having an electron-withdrawing group at the meta position of a benzene ring, a second structural unit derived from divinylbenzene, and formula 1: 【Chemistry 1】 It includes a third structural unit derived from an allyl sulfonic acid compound represented by formula 1, where R １ , R ２ and R ３ Each of these is independently hydrogen or a C1-C2 alkyl group, M is H or a metallic element, and here, a part of the benzene ring in the first structural unit is -SO ３ An acidic resin containing H groups.

2. The copolymer in the acidic resin comprises a first structural unit shown in formula 2, a second structural unit shown in formula 3, and a third structural unit shown in formula 4. 【Chemistry 2】 Here, Y in equation 2 is -SO ３ H and X are electron-withdrawing groups, and R in formula 4 １ , R ２ and R ３ The acidic resin according to claim 1, characterized in that each of them is independently hydrogen or a C1-C2 alkyl group.

3. The electron-withdrawing group is selected from the group consisting of halogen atoms, nitro groups, nitroso groups, C1-C4 alkoxy groups, and C1-C4 alkanoyloxy groups, such as acetoxy groups, and / or The acidic resin according to claim 1 or 2, characterized in that, when the total weight of the copolymer is 100% by weight, the content of the first structural unit is 1 to 50% by weight, the content of the second structural unit is 30 to 90% by weight, and the content of the third structural unit is 1 to 50% by weight, preferably, when the total weight of the copolymer is 100% by weight, the content of the first structural unit is 15 to 40% by weight, the content of the second structural unit is 30 to 70% by weight, and the content of the third structural unit is 10 to 45% by weight.

4. The specific surface area of the acidic resin is 200 to 600 m ２ ·g －１ , preferably 200 to 500 m ２ ·g －１ and / or The pore volume of the aforementioned acidic resin is 0.2 to 0.8 cm². ３ ・g －１ Preferably 0.2 to 0.7 cm ３ ・g －１ And / or, The pore size of the acidic resin is 1 to 20 nm, preferably 5 to 20 nm, and / or The acid content of the aforementioned acidic resin is 1 to 10 mmol / g. －１ Preferably 3 to 8 mmol / g －１ The acidic resin according to any one of claims 1 to 3, characterized in that it is the acidic resin according to any one of claims 1 to 3.

5. The acidic resin according to any one of claims 1 to 4, characterized in that the acidic resin is used as a catalyst, preferably as a catalyst for preparing isosorbide from hexitol.

6. A step of copolymerizing divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, and an allyl sulfonic acid compound represented by formula 1 in the presence of a dispersant and an initiator to obtain a resin matrix; 【Transformation 3】 (In the formula, R １ , R ２ and R ３ Each of these is independently hydrogen or a C1-C2 alkyl group, and M is H or a metallic element. ); and The step of sulfonating the resin matrix to obtain an acidic resin, A preparation method according to any one of claims 1 to 5, including the method described in any one of claims 1 to 5.

7. (1) A step of mixing a solution containing the dispersant with a mixed solution containing divinylbenzene, styrene having an electron-withdrawing group at the meta position of the benzene ring, an allyl sulfonic acid compound of formula 1, and the initiator, and carrying out a polymerization reaction to obtain a resin matrix; (2) The step of mixing the resin matrix with an organic solvent containing a pore-expanding agent to obtain a mixed solution containing the resin matrix; and (3) A step of obtaining an acidic resin by bringing the mixed solution containing the resin matrix into contact with a sulfonating agent to perform sulfonation, and optionally washing and / or drying it. The preparation method according to claim 6, characterized by including the following:

8. The dispersant is selected from at least one of polyvinyl alcohol and hydroxyethylcellulose, preferably polyvinyl alcohol having a number average molecular weight of 50,000 to 100,000, and / or The initiator is an azo compound and / or peroxide, preferably at least one of benzoyl peroxide, phenylacetyl peroxide, potassium peroxide, and azobisisobutyronitrile, and / or The preparation method according to claim 6 or 7, characterized in that the pore-expanding agent is at least one of dichloromethane, dichloroethane, and n-heptane.

9. The amount of initiator used is 0.2 to 6 parts by mass, preferably 0.5 to 4 parts by mass, per 100 parts by mass of total monomer, and the amount of dispersant used is 1 to 10 parts by mass, and / or The preparation method according to any one of claims 6 to 8, wherein the amount of the pore-expanding agent is 2 to 40 parts by mass, preferably 2 to 30 parts by mass, per 100 parts by mass of the resin matrix.

10. The conditions for the polymerization reaction in step (1) are that the temperature is 60 to 150°C and / or the time is 3 to 14 hours, and / or In step (2), mixing the resin matrix with the organic solvent containing the pore-expanding agent includes raising the temperature of the mixture to 30 to 100°C, preferably 40 to 100°C, at a rate of 0.1 to 3°C / min, and / or The conditions for sulfonation in step (3) include a temperature of 30 to 100°C, preferably 40 to 100°C, and / or a time of 5 to 20 hours, and / or The preparation method according to claim 7, characterized in that the sulfonating agent comprises a strong acid, the strong acid being selected from at least one of concentrated sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, and methanesulfonic acid.

11. The use of an acidic resin according to any one of claims 1 to 5, or an acidic resin prepared by the preparation method according to any one of claims 6 to 10, as a catalyst in the preparation of isosorbide.

12. A method for preparing isosorbide, 1) A step of contacting hexitol with a solid acid catalyst to carry out a primary dehydration reaction and obtain a primary dehydration reaction product mixture; and 2) Remove the solid acid catalyst from the mixture produced by the primary dehydration reaction, and bring the resulting mixture into contact with an acidic resin to carry out a secondary dehydration reaction to obtain a reaction product containing isosorbide. A method comprising, wherein the acidic resin is the acidic resin described in any one of claims 1 to 5, or an acidic resin prepared by the preparation method described in any one of claims 6 to 10.

13. Hexitol is selected from sorbitol and / or mannitol, and / or Hexitol is solid hexitol and / or a solution of hexitol, and / or A method for preparing isosorbide according to claim 12, wherein the solid acid catalyst is selected from at least one of a molecular sieve, an acidic resin different from the acidic resin described in any one of claims 1 to 5 or the acidic resin prepared by the preparation method described in any one of claims 6 to 10, a metal phosphate, a Lewis acid, and a heteropoly acid, preferably at least one of a heteropoly acid and an acidic resin different from the acidic resin described in any one of claims 1 to 5 or the acidic resin prepared by the preparation method described in any one of claims 6 to 10, more preferably a heteropoly acid, and even more preferably a phosphotungstic acid solid acid catalyst.

14. In the primary dehydration reaction described above, the mass ratio of the solid acid catalyst to hexitol is (0.1 to 1.0):100, preferably (0.5 to 6):100, more preferably (1 to 5):100, and / or The selectivity of 1,4-sorbitan in the primary dehydration reaction is greater than 80%, preferably 85% or more, more preferably 90% or more, and / or In the aforementioned secondary dehydration reaction, the mass ratio of the acidic resin catalyst to hexitol is (1-10):100, preferably (2-6):100, and / or A method for preparing isosorbide according to claim 12 or 13, characterized in that the yield of isosorbide prepared by the secondary dehydration reaction exceeds 80%.

15. The conditions in step 1) include a reaction temperature of 80 to 130°C, and / or a residence time of 3 to 7 hours, and / or a reaction pressure of 0.001 to 1 atm, and / or A method for preparing isosorbide according to any one of claims 12 to 14, characterized in that the conditions in step 2) include a reaction temperature of 120 to 160°C and / or a residence time of 1 to 9 hours and / or a reaction pressure of 0.001 to 1 atm.

16. The water produced in the primary dehydration reaction is discharged from the top of the reactor during the reaction, the solid acid catalyst is removed from the mixture produced in the primary dehydration reaction after discharge from the reactor, and this mixture is then introduced into the reactor for the secondary dehydration reaction to carry out the reaction, and / or The mixture produced by the primary dehydration reaction is dehydrated before the secondary dehydration reaction and / or A method for preparing isosorbide according to any one of claims 12 to 15, wherein the preparation method further comprises purifying a reaction product containing isosorbide obtained after the secondary dehydration reaction to obtain purified isosorbide, and preferably the purification method is distillation and / or crystallization.

17. A method for preparing isosorbide according to any one of claims 12 to 16, wherein the preparation method is a continuous preparation method.

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