Polymer solid acid catalyst, its preparation method and application

Abstract

The application relates to the technical field of catalysts, in particular to a polymer solid acid catalyst and a preparation method and application thereof. The first aspect of the application provides a polymer solid acid catalyst, wherein the catalyst comprises a polymer, a group A and a conjugate acid of the group A; the polymer is an aromatic polymer; the structure of the group A is shown in the formula; n is an integer not less than 1; the group A is connected with a benzene ring in the polymer at the position of the asterisk; and the catalyst further comprises a metal element M which is coordinated with a single-bond oxygen in at least part of the group A. The polymer solid acid catalyst has strong acidity, good thermal stability and high catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a polymer solid acid catalyst, its preparation method, and its application. Background Technology

[0002] Biomass, with its renewable, abundant, highly functionalized, and environmentally friendly characteristics, has become a research hotspot in the fields of fine chemicals and new materials under the background of green development. Isosorbide, isomannitol, and isosorbide diol, as important bio-based platform compounds, possess unique molecular structures and are environmentally friendly and non-toxic green diols. They are widely used not only in pharmaceuticals, surfactants, and plastic additives, but also play a crucial role in the field of novel polymer materials. Therefore, the synthesis technology and applications of isosorbide have attracted much attention in recent years.

[0003] Currently reported synthetic routes for isosorbide mainly use sorbitol as a raw material and liquid or solid acid as a catalyst for catalytic dehydration. From the reaction principle, the catalytic dehydration of sorbitol to isosorbide involves two dehydration steps: the first step yields 1,4-dehydrated sorbitol, and the second step yields isosorbide. However, because the sorbitol molecule has six hydroxyl groups, multiple dehydration reaction pathways exist, potentially generating various byproducts. These byproducts can further generate humic substances under catalysis. Liquid acids are mainly concentrated sulfuric acid and benzenesulfonic acid. Although this homogeneous process is relatively mature, the generation of multiple dehydration byproducts makes product separation complex, easily corrodes equipment, increases production costs, and is not conducive to large-scale industrial application. Solid acids mainly include molecular sieves, ion exchange resins, metal phosphates, and heteropoly acids. Due to their advantages such as low requirements for equipment materials, relatively simple product separation, and catalyst recyclability, solid acid catalysts have attracted attention and are gradually replacing liquid acid catalysts. However, solid acid catalyst technology is still immature, with issues in catalyst lifetime and selectivity at high temperatures, thus hindering large-scale industrial application. Literature reports that in the catalytic dehydration synthesis of isosorbide, strong acidic ion exchange resins are used as solid acid catalysts, showing good performance in conversion and selectivity. However, the catalyst lifetime is limited, especially at reaction temperatures above 120°C, where sulfonic acid groups easily detach, significantly reducing acidity. This cannot meet the requirements of continuous isosorbide production processes, leading to higher production costs and unstable product quality, thus limiting its industrial application. Summary of the Invention

[0004] To overcome the problem that the sulfonic acid groups of solid acids are easily detached when heated, resulting in a decrease in their catalytic activity for isosorbide, a polymer solid acid catalyst, its preparation method, and its application are provided. This polymer solid acid catalyst has strong acidity, good thermal stability, and high catalytic activity.

[0005] To achieve the above objectives, a first aspect of the present invention provides a polymer solid acid catalyst, the catalyst comprising a polymer, a group A, and a conjugate acid of the group A;

[0006] The polymer is an aromatic polymer;

[0007] The structure of group A is as follows: Where n is selected from integers not less than 1;

[0008] The group A is attached to the benzene ring in the polymer at the asterisk position;

[0009] The catalyst further comprises a metal element M, which is coordinated with a single-bonded oxygen in at least a portion of the group A.

[0010] A second aspect of the present invention provides a method for preparing the polymer solid acid catalyst provided in the first aspect of the present invention, the method comprising:

[0011] (1) In the presence of an acid and an optional solvent, the polymer is mixed with a haloalkylating agent and reacted to obtain a haloalkylated polymer;

[0012] (2) In the presence of a solvent and an activator, the haloalkylated polymer is subjected to an addition reaction with an α-olefin sulfonate, and after acidification, an alkylsulfonated polymer is obtained.

[0013] (3) In the presence of a solvent, the alkyl sulfonated polymer is mixed with and impregnated with a metal compound to obtain a polymer solid acid catalyst.

[0014] The third aspect of the present invention provides the application of the polymer solid acid catalyst provided in the first aspect of the present invention in the synthesis of isosorbide.

[0015] A fourth aspect of the present invention provides a method for synthesizing isosorbide using a polymer solid acid catalyst provided in the first aspect of the present invention, the method comprising the following steps:

[0016] (1) Sorbitol and the polymer solid acid catalyst are mixed at a mass ratio of 1:0.01-0.1;

[0017] (2) React at 110-130℃ and 40-80kPa absolute pressure for 3-7 hours;

[0018] (3) React at 135-200℃ and 5-40kPa absolute pressure for 5-10h;

[0019] (4) Isosorbide was isolated.

[0020] The beneficial effects of this invention are as follows:

[0021] First, the polymer solid acid catalyst provided by the present invention contains alkyl sulfonic acid groups and active metals, and has both Brønsted acid centers and Lewis acid centers. It is highly acidic, exhibits high catalytic activity in the synthesis of isosorbide, and has good thermal stability, making it reusable.

[0022] Secondly, the polymer solid acid catalyst provided by this invention exhibits good thermal stability. When used to synthesize isosorbide, it can react under high-temperature conditions, displaying different activities and selectivities at different temperatures: at lower temperatures, sorbitol selectively undergoes 1,4-dehydration; under high-temperature conditions, the 1,4-dehydrated product further loses one molecule of water to obtain isosorbide. This method of synthesizing isosorbide results in high selectivity, few byproducts, high product purity, and easy separation of the catalyst and product. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a polymer solid acid catalyst, the catalyst comprising a polymer, a group A, and a conjugate acid of the group A;

[0025] The polymer is an aromatic polymer;

[0026] The structure of group A is as follows: Where n is selected from integers not less than 1;

[0027] The group A is attached to the benzene ring in the polymer at the asterisk position;

[0028] The catalyst further comprises a metal element M, which is coordinated with a single-bonded oxygen in at least a portion of the group A.

[0029] In the catalyst provided by this invention, the conjugate acid of group A can provide Brønsted acid (B acid). The metal element M can provide Lewis acid (L-acid) centers. Furthermore, the sulfonic acid group in group A is linked to the benzene ring in the polymer via an alkyl group, rather than directly onto the benzene ring, which significantly improves the thermal stability of the catalyst. The catalyst maintains high acidity at high temperatures, making it particularly suitable for catalyzing the synthesis of isosorbide.

[0030] According to a preferred embodiment of the present invention, the metal element M has a valence of divalent, and the polymer solid acid catalyst comprises the following structure:

[0031]

[0032] Where Ph is phenyl, R1 and R2 are each independently derived from aromatic polymers, and n and m are each independently selected from integers not less than 1.

[0033] According to a preferred embodiment of the present invention, the metal element M has a valence of trivalent, and the polymer solid acid catalyst comprises the following structure:

[0034]

[0035] Wherein, Ph is phenyl, R1 and R2 are each independently derived from aromatic polymers, n and m are each independently selected from integers not less than 1, and X is selected from at least one of chloride ions, sulfate ions and nitrate ions, wherein the number of X ions is such that the above structure satisfies electroneutrality.

[0036] According to a preferred embodiment of the present invention, the metal element M has a tetravalent oxidation state, and the polymer solid acid catalyst comprises the following structure:

[0037]

[0038] Wherein, Ph is phenyl, R1 and R2 are each independently derived from aromatic polymers, n and m are each independently selected from integers not less than 1, and X is selected from at least one of chloride ions, sulfate ions and nitrate ions, wherein the number of X ions is such that the above structure satisfies electroneutrality.

[0039] According to a preferred embodiment of the present invention, the polymer is a styrene copolymer and / or a polyarylether.

[0040] In this invention, styrene copolymers and polyarylethers exhibit better stability under high-temperature reaction conditions compared to other aromatic polymers.

[0041] More preferably, the styrene copolymer is selected from at least one of polystyrene-divinylbenzene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer and styrene-acrylate copolymer.

[0042] More preferably, the polyarylether is selected from at least one of polyetherketone, polyetheretherketone, polyetherketoneketone, polyethersulfone, and polyaryletherketonesulfone.

[0043] According to the present invention, preferably, the metal element M is selected from at least one of divalent, trivalent and tetravalent metal elements.

[0044] More preferably, the metallic element M is selected from at least one of zinc, aluminum, iron, and tin.

[0045] In this invention, zinc, aluminum, iron, and tin can provide L-acid centers.

[0046] According to the present invention, preferably, n is selected from an integer from 1 to 4.

[0047] In this invention, when n is selected from the above range, the sulfonic acid group has better stability.

[0048] According to a preferred embodiment of the present invention, the catalyst contains 20-70 wt% C, 5-50 wt% O, 10-50 wt% S, and 0.1-10 wt% metal elements.

[0049] In this invention, when the contents of C, O, S and metal elements in the catalyst are within the above-mentioned ranges, the catalyst has better stability and catalytic performance.

[0050] More preferably, the catalyst contains 30-60 wt% C, 10-40 wt% O, 20-40 wt% S, and 2-8 wt% metal elements.

[0051] More preferably, the catalyst contains 40-50 wt% C, 20-30 wt% O, 25-35 wt% S, and 4-6 wt% metal elements.

[0052] According to a preferred embodiment of the present invention, the acid strength of the catalyst is 1-10 mmol / g [H]. + ].

[0053] More preferably, the catalyst has an acid strength of 3.5-6 mmol / g [H2O]. + At this point, the catalyst exhibits better reactivity and stability.

[0054] According to the present invention, preferably, based on the total amount of acid centers in the catalyst, the content of Brønsted acid centers in the catalyst is 80-99 mol%, and the content of Lewis acid centers is 1-20 mol%.

[0055] In this invention, when the contents of Brønsted acid centers and Lewis acid centers are within the above-mentioned range, the catalyst can provide good reactivity and selectivity.

[0056] More preferably, based on the total amount of acid centers in the catalyst, the content of Brønsted acid centers in the catalyst is 90-95 mol%, and the content of Lewis acid centers is 5-10 mol%.

[0057] According to the present invention, preferably, the catalyst has a specific surface area of ​​20-600 m². 2 ·g -1 .

[0058] In this invention, when the specific surface area of ​​the catalyst is within the above-mentioned range, the catalyst has higher reactivity.

[0059] More preferably, the catalyst has a specific surface area of ​​300-500 m². 2 ·g -1 .

[0060] According to the present invention, preferably, the pore volume of the catalyst is 0.1-0.8 cm³. 3 ·g -1 .

[0061] In this invention, when the pore volume of the catalyst is within the above-mentioned range, the selectivity of the catalyst is higher.

[0062] More preferably, the catalyst has a pore volume of 0.2-0.5 cm³. 3 ·g -1 .

[0063] According to the present invention, preferably, the catalyst has an average pore size of 5-50 nm.

[0064] In this invention, when the average pore size of the catalyst is within the above-mentioned range, the selectivity of the catalyst is higher.

[0065] More preferably, the catalyst has an average pore size of 20-40 nm.

[0066] According to the present invention, preferably, the dry basis water content of the catalyst is ≤3wt%.

[0067] According to the present invention, preferably, the bulk density of the catalyst is 0.2-0.8 g / mL.

[0068] In this invention, when the bulk density of the catalyst is within the above-mentioned range, the catalyst can be suspended in sorbitol liquid.

[0069] More preferably, the bulk density of the catalyst is 0.5-0.65 g / mL.

[0070] A second aspect of the present invention provides a method for preparing the polymer solid acid catalyst provided in the first aspect of the present invention, the method comprising:

[0071] (1) In the presence of an acid and an optional solvent, the polymer is mixed with a haloalkylating agent and reacted to obtain a haloalkylated polymer;

[0072] (2) In the presence of a solvent and an activator, the haloalkylated polymer is subjected to an addition reaction with an α-olefin sulfonate, and after acidification, an alkylsulfonated polymer is obtained.

[0073] (3) In the presence of a solvent, the alkyl sulfonated polymer is mixed with and impregnated with a metal compound to obtain a polymer solid acid catalyst.

[0074] In this invention, the above method can enter the active site at a specific position in the polymer, and efficiently and accurately alkylate the polymer.

[0075] According to a preferred embodiment of the present invention, in step (1), the mass ratio of the polymer to the haloalkylating agent is 1:0.1-2.

[0076] In this invention, when the mass ratio of the polymer to the haloalkylating agent is within the above-mentioned range, a more suitable amount of haloalkyl can be introduced onto the benzene ring of the polymer.

[0077] More preferably, the mass ratio of the polymer to the haloalkylating agent is 1:0.3-1.

[0078] The present invention does not impose a particular limitation on the amount of acid used, as long as it can effectively catalyze the haloalkylation reaction; those skilled in the art can choose the appropriate amount conventionally. According to one specific embodiment of the present invention, the mass ratio of the polymer to the acid is 1:0.01-0.1.

[0079] This invention does not particularly limit the specific type of the haloalkylating agent, and those skilled in the art can choose it conventionally. According to one specific embodiment of the invention, the haloalkylating agent is selected from at least one of haloalkanes, haloalcohols, haloethers, and haloalkyl sulfates, such as chloromethane, chloromethanol, and methylchloromethyl ether (CAS107-30-2).

[0080] The present invention does not particularly limit the specific type of acid, and those skilled in the art can choose conventionally. According to a specific embodiment of the present invention, in step (1), the acid can be a Brønsted acid such as hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid, or a Lewis acid such as zinc chloride, aluminum chloride, ferric chloride, tin chloride, and stannous chloride.

[0081] The present invention does not impose any particular limitation on the reaction conditions in step (1), and those skilled in the art can choose them conventionally. According to a specific embodiment of the present invention, the reaction temperature in step (1) is 40-120°C, and the time is 1-10 hours.

[0082] According to a preferred embodiment of the present invention, in step (2), the mass ratio of the halogenated alkylated polymer to the α-olefin sulfonate is 1:0.1-1.

[0083] In this invention, when the mass ratio of the haloalkylated polymer to the α-olefin sulfonate is within the above-mentioned range, the addition reaction can proceed more fully.

[0084] More preferably, the mass ratio of the haloalkylated polymer to the α-olefin sulfonate is 1:0.4-0.6.

[0085] The present invention does not impose a particular limitation on the amount of the activator, as long as it can effectively catalyze the addition reaction; those skilled in the art can choose it conventionally. According to a specific embodiment of the present invention, the mass ratio of the haloalkylated polymer to the activator is 1:0.01-0.1.

[0086] The present invention does not particularly limit the specific type of the activator, and those skilled in the art can choose it conventionally. According to one specific embodiment of the present invention, the activator is selected from at least one of potassium tert-butoxide, sodium hydride, sodium ethoxide, and potassium carbonate.

[0087] According to the present invention, preferably, the α-olefin sulfonate is sodium vinyl sulfonate (CAS#: 3039-83-6) and / or sodium allyl sulfonate (CAS#: 2495-39-8).

[0088] In this invention, when the α-olefin sulfonate is selected from the above range, the resulting catalyst can have better stability.

[0089] This invention does not impose any particular limitation on the specific conditions of the addition reaction, and those skilled in the art can choose them conventionally. According to one specific embodiment of the invention, the temperature of the addition reaction is 100-180°C, and the time is 8-24 hours.

[0090] The present invention does not particularly limit the specific conditions of acidification, and those skilled in the art can choose conventionally. According to a specific embodiment of the present invention, in step (2), the acid added is selected from at least one of sulfuric acid, hydrochloric acid, phosphoric acid and p-toluenesulfonic acid, the acidification temperature is 50-100°C, the time is 1-10h, and the mass ratio of the alkylsulfonated polymer to the acid added in step (2) is 1:0.4-1.

[0091] According to a preferred embodiment of the present invention, in step (3), the mass ratio of the alkylsulfonated polymer to the metal compound is 1:0.05-0.2.

[0092] In this invention, when the mass ratio of the alkylsulfonated polymer to the metal compound is within the above-mentioned range, a catalyst with a preferred content of Brønsted acid centers and Lewis acid centers can be obtained.

[0093] More preferably, in step (3), the mass ratio of the alkylsulfonated polymer to the metal compound is 1:0.05-0.2.

[0094] The present invention does not particularly limit the specific type of the metal compound, and those skilled in the art can choose conventionally. According to one specific embodiment of the present invention, the metal compound is selected from soluble salts capable of providing at least one metal selected from zinc, aluminum, iron, and tin.

[0095] The present invention does not impose any particular limitation on the impregnation conditions, and those skilled in the art can choose them conventionally. According to one specific embodiment of the present invention, the impregnation temperature is 20-100°C, and the time is 5-24 hours.

[0096] The present invention does not particularly limit the specific type of solvent, and those skilled in the art can conventionally select polar and non-polar solvents as needed. For example, the solvents in steps (1) and (2) can each be independently selected from non-polar solvents, such as xylene and other aromatic solvents; the solvent in step (3) can be a polar solvent, such as ethanol and other lower alcohols.

[0097] The present invention does not impose any particular limitation on the separation method in step (4), and those skilled in the art can choose conventional methods. For example, a combination of vacuum distillation and recrystallization can be used to separate and purify isosorbide from the product, and the specific operating conditions can be conventionally selected by those skilled in the art.

[0098] The third aspect of the present invention provides the application of the polymer solid acid catalyst provided in the first aspect of the present invention in the synthesis of isosorbide.

[0099] A fourth aspect of the present invention provides a method for synthesizing isosorbide using a polymer solid acid catalyst provided in the first aspect of the present invention, the method comprising the following steps:

[0100] (1) Sorbitol and the polymer solid acid catalyst are mixed at a mass ratio of 1:0.01-0.1;

[0101] (2) React at 110-130℃ and 40-80kPa absolute pressure for 3-7 hours;

[0102] (3) React at 135-200℃ and 5-40kPa absolute pressure for 5-10h;

[0103] (4) Isosorbide was isolated.

[0104] In this invention, the above-mentioned method for synthesizing isosorbide can fully utilize the characteristics of the polymer solid acid catalyst provided by this invention, which has strong acidity and high thermal stability, resulting in high selectivity, few by-products, and high product purity in the synthesis of isosorbide.

[0105] The present invention will be described in detail below through embodiments.

[0106] In the following examples, the contents of Brønsted acid centers and Lewis acid centers were determined by adsorption probe molecule method using Fourier transform infrared spectroscopy (FT-IR), and the probe molecule was pyridine.

[0107] In the infrared spectrum, the characteristic peak of the Brønsted acid center is located at ~1540 cm⁻¹. -1 At this location, the characteristic peak of the L-acid center is located at ~1450 cm⁻¹. -1 The content of Brønsted acid centers and Lewis acid centers is the ratio of the areas of their corresponding characteristic peaks.

[0108] The method for determining specific surface area is in accordance with GB / T 19587-2017;

[0109] The methods for determining pore volume and average pore diameter are in accordance with GB / T 21650.2-2008;

[0110] Moisture content on a dry basis was determined by the drying method;

[0111] The determination of bulk density shall be in accordance with SN / T2712-2010;

[0112] Elemental content was determined using X-ray energy dispersive spectroscopy (EDS).

[0113] The purity of 1,4-dehydrated sorbitol and isosorbide was determined by high performance liquid chromatography.

[0114] The stage yield of 1,4-dehydrated sorbitol = molar amount of 1,4-dehydrated sorbitol in the intermediate product / molar amount of sorbitol in the feed × 100%;

[0115] Isosorbide yield = (molar amount of isosorbide in the product / molar amount of sorbitol in the raw material) × 100%.

[0116] Unless otherwise specified, all raw materials and reagents are commercially available.

[0117] Polystyrene-divinylbenzene copolymer, polyetheretherketone and polyethersulfone were purchased from Bailingwei Company.

[0118] Examples 1-5

[0119] The polymer solid acid catalyst was prepared according to the following steps:

[0120] (1) Take 100g of polystyrene-divinylbenzene copolymer and add it to the reactor. Then add methyl chloromethyl ether (CAS107-30-2) and 3g of anhydrous zinc chloride. Heat to reflux temperature of 60℃, stir and keep warm for 5h. After cooling to room temperature, filter to obtain chloroalkylated polymer.

[0121] (2) Take 100g of the above chloroalkylated polymer, add 172g of xylene, then add 50g of sodium vinyl sulfonate and 3g of potassium tert-butoxide, heat to reflux temperature of 130℃ and react for 12h to obtain the product with sodium alkyl sulfonate introduced. Take 100g of the above product and add it to the reactor, add 100g of xylene, slowly heat to 70℃, then add 50g of concentrated sulfuric acid (98wt%) dropwise, continue to react for 3h, after the reaction is completed, cool to room temperature, filter and separate, wash with deionized water until neutral, filter again to obtain the alkylsulfonated polymer.

[0122] (3) Take 100g of the above alkyl sulfonated polymer and add it to the reactor. Add 120g of ethanol as a solvent, and then add zinc chloride. Impregnate at 50°C for 8h. After impregnation, wash and filter, and then dry at 80°C for 10h to obtain the polymer solid acid catalyst.

[0123] The amounts of methyl chloromethyl ether added in step (1) and zinc chloride added in step (3) are as shown in Table 1.

[0124] Table 1

[0125]

[0126] Example 6

[0127] The polymer solid acid catalyst was prepared according to the method of Example 1, except that instead of adding polystyrene-divinylbenzene copolymer, 100g of polyether ether ketone was added to obtain the polymer solid acid catalyst.

[0128] Example 7

[0129] The polymer solid acid catalyst was prepared according to the method of Example 1, except that instead of adding polystyrene-divinylbenzene copolymer, 100g of polyethersulfone was added to obtain the polymer solid acid catalyst.

[0130] Example 8

[0131] The polymer solid acid catalyst was prepared according to the method of Example 1, except that sodium vinyl sulfonate was not added, but 50g of sodium allyl sulfonate was added to obtain the polymer solid acid catalyst.

[0132] Comparative Example 1

[0133] 100g of polystyrene-divinylbenzene copolymer was added to the reactor, along with 100g of xylene. The temperature was slowly raised to 70°C, and then 50g of concentrated sulfuric acid (98wt%) was added dropwise. The reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed with deionized water until neutral, and filtered again to obtain the sulfonated polymer.

[0134] Comparative Example 2

[0135] The polymer solid acid catalyst, Amberlyst 15, was purchased from Inokai. In this solid acid catalyst, the sulfonic acid is directly linked to the benzene ring of the polymer.

[0136] Test Example 1

[0137] The total acid content, Brønsted acid center content, Lewis acid center content, specific surface area, pore volume, average pore diameter, dry basis moisture content, and bulk density of the polymer solid acid catalysts obtained in the above examples and comparative examples were measured, and the results are shown in Table 2.

[0138] Table 2

[0139]

[0140] Test Example 2

[0141] The elemental composition of Examples 1-5 and Example 8 was determined, and the results are shown in Table 3.

[0142] Table 3

[0143]

[0144]

[0145] Application examples

[0146] (1) Add 100g of solid sorbitol to the reactor, and add 3g of the polymer solid acid catalyst obtained in the above examples and comparative examples respectively;

[0147] (2) Heat to 120°C, evacuate to 60 kPa (absolute pressure), keep the reaction at this temperature for 3 hours, and analyze the stage yield of 1,4-dehydrated sorbitol by sampling.

[0148] (3) The temperature was then further increased to 145℃, and the vacuum was increased to 10 kPa (absolute pressure). After reacting for 6 hours, the mixture was cooled to room temperature, filtered to remove the catalyst, and the resulting filtrate was distilled at 160℃ and 5 mbar (absolute pressure). The crude product obtained by distillation was cooled and solidified, then dissolved in a mixed solvent of 3 times its mass (isopropanol and n-hexane in a mass ratio of 12:1). After cooling to 20℃, the mixture was crystallized and dried at 50℃ for 8 hours to obtain isosorbide product. The purity and yield of the product are shown in Table 4.

[0149] Table 4

[0150] Yield (%) of 1,4-dehydrated sorbitol stage Isosorbide purity (wt%) Isosorbide yield (%) Example 1 92 99 81.2 Example 2 91 99 80.5 Example 3 95 99 83.5 Example 4 90 99 80.9 Example 5 85 99 80.1 Example 6 92 99 82.6 Example 7 93 99 82.7 Example 8 94 99 83.1 Comparative Example 1 75 99 71.2 Comparative Example 2 65 99 60.3

[0151] As can be seen from the results in Table 4, when isosorbide is synthesized using the polymer solid acid catalyst provided by this invention, the yield of the 1,4-dehydrated sorbitol stage is high, and the selectivity of isosorbide is high, with few byproducts and high purity.

[0152] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polymer solid acid catalyst, characterized in that, The catalyst comprises a polymer, as well as group A and the conjugate acid of group A; The polymer is an aromatic polymer; The structure of group A is as follows: Where n is selected from integers not less than 1; The group A is attached to the benzene ring in the polymer at the asterisk position; The catalyst further comprises a metal element M, which is coordinated with a single-bonded oxygen in at least a portion of the group A.

2. The catalyst according to claim 1, characterized in that, The polymer is a styrene copolymer and / or a polyarylene ether; Preferably, the styrene copolymer is selected from at least one of polystyrene-divinylbenzene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-acrylate copolymer; Preferably, the polyarylether is selected from at least one of polyetherketone, polyetheretherketone, polyetherketoneketone, polyethersulfone, and polyaryletherketonesulfone; Preferably, the metal element M is selected from at least one divalent, trivalent, and tetravalent metal element, and more preferably from at least one of zinc, aluminum, iron, and tin; Preferably, n is selected from an integer from 1 to 4.

3. The catalyst according to claim 1 or 2, characterized in that, The catalyst contains 20-70 wt% carbon, 5-50 wt% oxygen, 10-50 wt% sulfur, and 0.1-10 wt% metallic elements.

4. The catalyst according to any one of claims 1-3, characterized in that, The acid strength of the catalyst is 1-10 mmol / g [H]. + ]; Preferably, based on the total amount of acid centers in the catalyst, the content of Brønsted acid centers in the catalyst is 80-99 mol%, and the content of Lewis acid centers is 1-20 mol%.

5. The catalyst according to any one of claims 1-4, characterized in that, The catalyst has a specific surface area of ​​20-600 m². 2 ·g -1 ; Preferably, the catalyst has a pore volume of 0.1-0.8 cm³. 3 ·g -1 ; Preferably, the catalyst has an average pore size of 5-50 nm; Preferably, the dry basis water content of the catalyst is ≤3wt%. Preferably, the bulk density of the catalyst is 0.2-0.8 g / mL.

6. A method for preparing the polymer solid acid catalyst according to any one of claims 1-5, characterized in that, The method includes: (1) In the presence of an acid and an optional solvent, the polymer is mixed with a haloalkylating agent and reacted to obtain a haloalkylated polymer; (2) In the presence of a solvent and an activator, the haloalkylated polymer is subjected to an addition reaction with an α-olefin sulfonate, and after acidification, an alkylsulfonated polymer is obtained. (3) In the presence of a solvent, the alkyl sulfonated polymer is mixed with and impregnated with a metal compound to obtain a polymer solid acid catalyst.

7. The method according to claim 6, characterized in that, In step (1), the mass ratio of the polymer to the haloalkylating agent is 1:0.2-2; Preferably, the mass ratio of the polymer to the acid is 1:0.01-0.1; Preferably, the halogenated alkylating agent is selected from at least one of halogenated alkanes, halogenated alcohols, halogenated ethers, and halogenated alkyl sulfates; Preferably, in step (1), the reaction temperature is 40-120℃ and the time is 1-10h.

8. The method according to claim 6 or 7, characterized in that, In step (2), the mass ratio of the halogenated alkylated polymer to the α-olefin sulfonate is 1:0.1-1; Preferably, the mass ratio of the halogenated alkylated polymer to the activator is 1:0.01-0.1; Preferably, the activator is selected from at least one of potassium tert-butoxide, sodium hydride, sodium ethoxide, and potassium carbonate; Preferably, the α-olefin sulfonate is sodium vinyl sulfonate and / or sodium allyl sulfonate; Preferably, the addition reaction is carried out at a temperature of 100-180°C for 8-24 hours. Preferably, the acidification temperature is 50-100℃ and the time is 1-10h.

9. The method according to any one of claims 6-8, characterized in that, In step (3), the mass ratio of the alkylsulfonated polymer to the metal compound is 1:0.05-0.2; Preferably, the metal compound is a soluble salt capable of providing at least one metal selected from zinc, aluminum, iron, and tin; Preferably, the impregnation temperature is 20-100℃ and the time is 5-24h.

10. The use of a polymer solid acid catalyst according to any one of claims 1-6 in the synthesis of isosorbide.

11. A method for synthesizing isosorbide using a polymer solid acid catalyst according to any one of claims 1-6, characterized in that, The method includes the following steps: (1) Sorbitol and the polymer solid acid catalyst are mixed at a mass ratio of 1:0.01-0.1; (2) React at 110-130℃ and 40-80kPa absolute pressure for 3-7 hours; (3) React at 135-200℃ and 5-40kPa absolute pressure for 5-10h; (4) Isosorbide was isolated.

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