Supported sulfonated phenolic resin solid acid catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and provides a supported sulfonated phenolic resin solid acid catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out hydrophobic modification on the surface of a carrier by adopting a silane coupling agent to obtain a modified carrier; then carrying out polymerization in-situ growth on soluble phenolic resin and a curing agent on the modified carrier to obtain a phenolic resin-loaded modified carrier; the preparation method of the supported sulfonated phenolic resin solid acid catalyst provided by the invention has the advantages that the process is simple, the cost is low, and the utilization rate of phenolic resin is high; the prepared catalyst is uniform in size, high in mechanical strength, not easy to crush, small in resistance and good in stability during liquid-phase flow catalytic continuous reaction, has good catalytic activity and high isosorbide yield when being used for catalyzing dehydration of sorbitol to prepare isosorbide, and can be recycled.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and more specifically to a supported sulfonated phenolic resin solid acid catalyst and a preparation method and application thereof. Background Art

[0002] Isosorbide, as an important biomass raw material, is widely used in the fields of medicine, liquid crystal materials, plasticizers, polymers, etc. Isosorbide is usually prepared by two-step dehydration of sorbitol under the action of an acid catalyst. Although the traditional liquid acid (sulfuric acid, hydrochloric acid or organic acid) catalytic process has high activity and low cost, it inevitably has many disadvantages during use, such as equipment corrosion, safety issues, cumbersome catalyst recovery process and generation of a large amount of waste liquid. Therefore, the research and development of environmentally friendly solid acid catalysts has attracted people's attention.

[0003] Phenolic resin has more benzene ring structures, and sulfonic acid groups can be introduced by suitable sulfonation methods, thereby showing solid acid catalytic performance. Publication number is that Chinese patent CN110560161A discloses a preparation method of sulfonated phenolic resin type solid acid catalyst and its application in glycerol esterification reaction, and adopts one-step polycondensation method to carry out polycondensation reaction of p-hydroxybenzenesulfonic acid, phenol and paraformaldehyde to prepare sulfonated phenolic resin type solid acid catalyst. The preparation method of the acid catalyst of this invention has simple process, safety and environmental protection, and the prepared sulfonated phenolic resin type solid acid catalyst has good stability, high catalytic activity, and can catalyze glycerol to carry out esterification reaction under relatively low temperature conditions. However, the catalyst is powdery, and in the reaction process, it is difficult to separate and recycle.

[0004] The Chinese patent with publication number CN101550223A discloses a sulfonated phenolic resin and its preparation and application as a catalyst, and provides a sulfonated phenolic resin, which is prepared by synthesizing phenolic resin with phenol and formaldehyde as raw materials and then sulfonating it under appropriate conditions. The sulfonated phenolic resin catalyst is used for the catalytic synthesis reaction of trioctyl citrate and tributyl citrate. The results show that the esterification rate of tributyl citrate is 99%, and the esterification rate of trioctyl citrate is more than 96%. However, the prepared catalyst is also in powder form, and it is not easy to separate and recycle during the reaction process.

[0005] In "Synthesis and Acid Catalytic Performance of Novel Ordered Mesoporous Sulfonated Phenolic Resin FDU-16-SO3H" (Journal of Chemistry in Universities, 2010, 31(08)), Mou Li et al. prepared a novel ordered mesoporous solid acid catalyst FDU-16-SO3H by sulfonating ordered mesoporous phenolic resin (FDU-16) with chlorosulfonic acid. The catalyst has a large specific surface area, strong acidity and hydrophobicity of the skeleton, and thus exhibits good catalytic activity in esterification and acylation reactions. However, the catalyst is in powder form and is also difficult to separate and recycle during the reaction process; and the preparation process is complicated, the cost is high, the yield is low, and it is difficult to apply industrially.

[0006] Although sulfonated phenolic resin is a strongly acidic cation exchange resin catalyst with a high acid content and a stable network structure, thus showing a good catalytic effect, the sulfonated phenolic resin powder is not easy to separate and recycle from the product during use, and has a large resistance in the flow catalytic reaction process. In addition, the polymerized phenolic resin itself has a small pore structure, resulting in a small active surface area, which limits the improvement of its activity.

[0007] Phenolic resin microspheres can also be prepared by suspension polymerization, but the droplet size during the reaction is difficult to control, and the resulting phenolic resin microspheres are small in size and uneven in size; in addition, the phenolic resin microspheres have a small surface area, poor mechanical strength, and are easily crushed.

[0008] Therefore, it is necessary to develop a sulfonated phenolic resin catalyst with uniform particle size, large surface area and good strength. Summary of the invention

[0009] The object of the present invention is to provide a supported sulfonated phenolic resin solid acid catalyst and a preparation method thereof, so as to solve the technical problems of uneven size and poor strength of the sulfonated phenolic resin catalyst in the prior art.

[0010] To achieve the above object, the technical solution adopted by the present invention is:

[0011] In a first aspect, the present invention provides a method for preparing a supported sulfonated phenolic resin solid acid catalyst, comprising: using a silane coupling agent to hydrophobically modify the surface of a carrier to obtain a modified carrier; then using a soluble phenolic resin and a curing agent to polymerize and grow in situ on the modified carrier to obtain a modified carrier loaded with phenolic resin; and then sulfonating the modified carrier loaded with phenolic resin to obtain the supported sulfonated phenolic resin solid acid catalyst.

[0012] The preparation method of the supported sulfonated phenolic resin solid acid catalyst provided by the present invention can effectively increase the dispersion and active surface area of ​​the resin by in-situ growing the phenolic resin on the surface of the carrier, thereby improving the catalytic activity of the sulfonated phenolic resin, and at the same time improving the utilization efficiency of the resin and reducing the catalyst cost.

[0013] It should be noted that the in-situ growth described in the present invention means that the phenolic resin first reacts chemically with the silanization agent on the surface of the carrier to be bonded to the surface, and then a surface polymerization reaction occurs.

[0014] In the present invention, a silane coupling agent is used to hydrophobize the surface of the carrier. On the one hand, the hydrophilic surface of the carrier can be hydrophobized, the growth amount of the phenolic resin on the surface of the carrier can be increased, and the selectivity of the catalyst can be improved. If the surface of the carrier is not hydrophobized, the phenolic resin is difficult to grow on its surface and is more likely to polymerize in the solution. On the other hand, the hydrophobicity of the catalyst surface is increased, which is conducive to the desorption of water generated after the reaction from the surface and the stability of the catalyst is increased.

[0015] In the present invention, the soluble phenolic resin refers to a phenolic resin that is soluble in water or an organic solvent.

[0016] According to some embodiments of the present invention, the carrier is an inorganic carrier.

[0017] According to some embodiments of the present invention, the carrier is selected from SiO 2 、Al 2 O 3 、TiO 2 , at least one of molecular sieves.

[0018] In the present invention, various common types of molecular sieves can be used as carriers, such as H-Beta molecular sieve, ZSM-5 molecular sieve, and the like.

[0019] According to some embodiments of the present invention, the carrier is a spherical carrier.

[0020] According to some embodiments of the present invention, the particle size of the carrier is 1 to 5 mm.

[0021] According to some embodiments of the present invention, the silane coupling agent includes at least one of trimethoxypropylsilane (PTMS), trimethoxy-n-octylsilane (OTMS), and trimethoxyhexadecylsilane (HTMS).

[0022] According to some embodiments of the present invention, the curing agent comprises hexamethylenetetramine

[0023] According to some embodiments of the present invention, the hydrophobic modification comprises: dispersing the carrier in a first solvent, adding the silane coupling agent at 40 to 80° C., and stirring to react to obtain the modified carrier;

[0024] According to some embodiments of the present invention, the first solvent includes a mixed solvent of aqueous ammonia, anhydrous ethanol and water.

[0025] According to some embodiments of the present invention, the concentration of the aqueous ammonia is 10 to 25 wt %.

[0026] According to some embodiments of the present invention, the mass ratio of the aqueous ammonia, anhydrous ethanol and water is 1:(1-5)::(1-5).

[0027] According to some embodiments of the present invention, the stirring reaction comprises stirring at a rotation speed of 100 to 1000 r / min for 24 to 72 hours.

[0028] According to some embodiments of the present invention, the mass ratio of the carrier to the silane coupling agent is 1:(0.025-1).

[0029] According to some embodiments of the present invention, the mass ratio of the carrier to the first solvent is 1:(1.5-8).

[0030] According to some embodiments of the present invention, the in-situ growth of polymerization on a modified carrier using a soluble phenolic resin and a curing agent includes: dissolving the soluble phenolic resin and the curing agent in a second solvent, adding the modified carrier, and reacting for 12-72 hours under a sealed condition of 80 to 200° C. to obtain a modified carrier loaded with phenolic resin. The reaction temperature can be selected from, for example, 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 150° C., 160° C., 180° C., 200° C., etc., and the reaction time can be selected from 12h, 18h, 24h, 28h, 36h, 40h, 48h, 55h, 60h, 67h, 72h, etc.

[0031] According to some embodiments of the present invention, the second solvent comprises at least one of methanol, ethanol, acetone and water.

[0032] According to some embodiments of the present invention, the mass ratio of the phenolic resin to the modified carrier is (0.05-0.50):1, preferably (0.1-0.5):1, more preferably (0.2-0.3):1, for example 0.3:1; the mass ratio of the phenolic resin to the curing agent is 10:(1-3); preferably 10:(1.5-2.5), for example 10:1.5.

[0033] According to some embodiments of the present invention, the mass ratio of the second solvent to the phenolic resin is (3-20):1, preferably (5-10):1.

[0034] According to some embodiments of the present invention, the sulfonation treatment comprises dispersing the modified carrier loaded with phenolic resin in a third solvent, adding a sulfonating agent and stirring the reaction for 2 to 8 hours to obtain the loaded sulfonated phenolic resin solid acid catalyst.

[0035] According to some embodiments of the present invention, the third solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene.

[0036] According to some embodiments of the present invention, the sulfonation reagent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide.

[0037] According to some embodiments of the present invention, the mass ratio of the modified carrier loaded with phenolic resin to the sulfonated reagent is (30-40): (1-10).

[0038] According to some embodiments of the present invention, the mass ratio of the modified carrier loaded with phenolic resin to the third solvent is (30-40): (60-80).

[0039] In a second aspect, the present invention provides a supported sulfonated phenolic resin solid acid catalyst, which is prepared by the preparation method described in the first aspect.

[0040] In a third aspect, the present invention provides use of the supported sulfonated phenolic resin solid acid catalyst described in the second aspect in catalyzing the dehydration of sorbitol to prepare isosorbide.

[0041] According to some embodiments of the present invention, the process conditions for preparing isosorbide by dehydrating sorbitol with the catalyst include: at normal pressure, the mass ratio of the catalyst to sorbitol is (0.01-0.2): 1, at 30 mL / min N 2 Under the condition of using protective gas and taking out water vapor, the reaction temperature is 100-180°C, the stirring speed is 300-1500r / min, and the reaction time is 1-4h.

[0042] The beneficial effects of the present invention are at least:

[0043] The preparation method of the supported sulfonated phenolic resin solid acid catalyst provided by the invention has the advantages of simple process, low cost and high utilization rate of phenolic resin; the prepared catalyst has uniform size, high mechanical strength and is not easy to be crushed; during the liquid phase flow catalytic continuous reaction, the resistance is small and the stability is good; the catalytic activity for catalyzing the dehydration of sorbitol to prepare isosorbide is good, the isosorbide yield is high and the catalyst can be recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 In Example 1, spherical SiO 2 Photograph of beads of surface-grown resin made from a carrier.

[0045] Figure 2 In Example 1, spherical SiO 2 Photo of the sulfonated phenolic resin solid acid catalyst prepared as a support.

[0046] Figure 3 This is a photograph of the polymerized powdered phenolic resin prepared in Comparative Example 1.

[0047] Figure 4 This is a photograph of the sulfonated phenolic resin powder catalyst prepared in Comparative Example 1. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent in detail and do not limit the scope of protection of the present invention in any way.

[0049] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the reagent amounts, unless otherwise specified, are the reagent amounts used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0050] In each embodiment and comparative example of the present invention, the product was analyzed by Agilent liquid chromatograph 1260Ⅱ and ZORBAX Extend Quantitative analysis using a chromatographic column and a differential refractive index detector.

[0051] Example 1

[0052] Add 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a 40°C constant temperature water bath for 10 min. Weigh 10 g of spherical SiO 2 (particle size 3mm) or spherical Al 2 O 3 (particle size 3mm) or spherical TiO 2(particle size is 3 mm), slowly add it into a three-necked flask and continue stirring for 5 minutes. Then, add 1 g of trimethoxyhexadecylsilane and continue stirring at 800 r / min for 24 hours. After the reaction is completed, the filtered solid is washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0053] Under stirring conditions, 2 g of soluble phenolic resin (2123) and 0.4 g of hexamethylenetetramine curing agent were dissolved in 40 mL of ethanol to obtain a clear solution, which was transferred to a hydrothermal kettle, and then 10 g of the modified inorganic carrier was added, and the reaction was sealed at 100 ° C for 48 hours. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water and dried to obtain pellets with surface-grown resin.

[0054] At room temperature, 10 g of pellets grown on different modified supports were added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 2 mL of chlorosulfonic acid was added and stirred for 4 h. After the reaction, the solid pellets were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain SiO 2 、Al 2 O 3 、TiO 2 Sulfonated phenolic resin solid acid catalyst.

[0055] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the above-prepared supported sulfonated phenolic resin solid acid catalyst after the sorbitol melts. Pass 30 mL / min N 2 As the protective gas and to carry out water vapor, at 150℃, 300r / min, the reaction was carried out for 2h and then the samples were taken for analysis. The reaction results are shown in Table 1.

[0056] Table 1 Effect of different carriers on catalyst performance

[0057]

[0058] Example 2

[0059] Add 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a 40°C constant temperature water bath for 10 min. 2 O 3 (particle size is 2 mm) was slowly added to a three-necked flask and stirred for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and stirred at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0060] Under stirring conditions, 1 g, 2 g, 3 g and 5 g of soluble phenolic resin (2123) and 20% of the mass of the phenolic resin hexamethylenetetramine curing agent were dissolved in 20 mL of ethanol to obtain clear solutions. The solutions with different phenolic concentrations were transferred to a hydrothermal kettle, and then the modified spherical Al 2 O 3 The carrier is 10 g, and the mixture is sealed and polymerized at 100° C. for 24 hours. After the reaction is completed, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with resin growing on the surface.

[0061] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 1 mL, 2 mL, 3 mL and 5 mL of chlorosulfonic acid were added, respectively, and stirred for 4 h. After the reaction, the solid pellets obtained by filtration were washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain sulfonated phenolic resin solid acid catalysts with different phenolic resin loadings.

[0062] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the above-prepared supported sulfonated phenolic resin solid acid catalyst after the sorbitol melts. Pass 30 mL / min N 2 As the protective gas and to bring out water vapor, at 150℃, 300r / min, the reaction was carried out for 2h and then the samples were taken for analysis. The reaction results are shown in Table 2.

[0063] Table 2 Effect of different phenolic resin loading on catalyst performance

[0064]

[0065] Example 3

[0066] Add 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a 40°C constant temperature water bath for 10 min. 2 O 3 (particle size is 2 mm) was slowly added to a three-necked flask and stirred for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and stirred at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0067] Under stirring conditions, 3 g of soluble phenolic resin (2123) and 10%, 15%, 20%, 25% and 30% of the mass of phenolic resin hexamethylenetetramine curing agent were dissolved in 20 mL of ethanol to obtain a clear solution. The solutions with different solid dosages were transferred to a hydrothermal kettle, and then the modified spherical Al 2 O 3 The carrier is 10 g, and the mixture is sealed and polymerized at 100° C. for 24 hours. After the reaction is completed, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with resin growing on the surface.

[0068] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 3 mL of chlorosulfonic acid was added to react for 4 h. After the reaction, the solid pellet obtained by filtration was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain supported sulfonated phenolic resin solid acid catalysts with different curing agent / phenolic resin ratios.

[0069] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the above-prepared supported sulfonated phenolic resin solid acid catalyst after the sorbitol melts. Pass 30 mL / min N 2 As protective gas and to carry out water vapor, at 150℃, 300r / min, the reaction was carried out for 2h and then the samples were taken for analysis. The reaction results are shown in Table 3.

[0070] Table 3 Effect of different curing agent / phenolic resin ratios on catalyst performance

[0071]

[0072]

[0073] Example 4

[0074] Add 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a 40°C constant temperature water bath for 10 min. 2 O 3 (particle size is 2 mm) was slowly added to a three-necked flask and stirred for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and stirred at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0075] Under stirring conditions, 3 g of soluble phenolic resin (2123) and 0.45 g of hexamethylenetetramine curing agent were dissolved in 20 mL of ethanol to obtain a clear solution. Five portions of the same solution were prepared and transferred to a hydrothermal kettle, respectively, and then the modified spherical Al 2 O 3 The carrier is 10 g, and the mixture is sealed and polymerized at 80°C, 100°C, 120°C, 150°C and 180°C for 24 hours. After the reaction, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with resin growing on the surface.

[0076] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 3 mL of chlorosulfonic acid was added to stir and react for 4 h. After the reaction, the solid pellet obtained by filtration was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain sulfonated phenolic resin solid acid catalysts with different phenolic resin loadings.

[0077] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the above-prepared supported sulfonated phenolic resin solid acid catalyst after the sorbitol melts. Pass 30 mL / min N 2 As the protective gas and to bring out water vapor, at 150℃, 300r / min, the reaction was carried out for 2h and then the samples were taken for analysis. The reaction results are shown in Table 4.

[0078] Table 4 Effect of different hydrothermal temperatures on catalyst performance

[0079]

[0080] Example 5

[0081] Add 5 mL of ammonia water (25 wt%), 10 g of anhydrous ethanol and 10 g of double distilled water into a three-necked flask and stir in a 40°C constant temperature water bath for 10 min. 2 O 3 (particle size is 2 mm) was slowly added to a three-necked flask and stirred for 5 min. Then, 1 g of trimethoxyhexadecylsilane was added and stirred at 800 r / min for 24 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a surface-modified carrier.

[0082] Under stirring conditions, 3 g of soluble phenolic resin (2123) and 0.45 g of hexamethylenetetramine curing agent were dissolved in 20 mL of ethanol to obtain a clear solution, which was transferred to a hydrothermal kettle and then the modified spherical Al 2 O3 The carrier is 10 g, and the mixture is sealed and polymerized at 120° C. for 12 h, 24 h and 48 h respectively. After the reaction is completed, the solid pellets obtained by filtration are washed with anhydrous ethanol and double distilled water, and dried to obtain pellets with resin growing on the surface.

[0083] At room temperature, 10 g of each pellet with different resin loading was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 3 mL of chlorosulfonic acid was added to stir and react for 4 h. After the reaction, the solid pellet obtained by filtration was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain sulfonated phenolic resin solid acid catalysts with different phenolic resin loadings.

[0084] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the above-prepared supported sulfonated phenolic resin solid acid catalyst after the sorbitol melts. Pass 30 mL / min N 2 As protective gas and to carry out water vapor, at 150℃, 300r / min, the reaction was carried out for 2h and then the samples were taken for analysis. The reaction results are shown in Table 5.

[0085] Table 5 Effect of different hydrothermal time on catalyst performance

[0086]

[0087] Comparative Example 1

[0088] The same hydrothermal method was used to prepare carrier-free sulfonated phenolic resin, and its performance in dehydrating sorbitol to isosorbide was evaluated. The process is as follows:

[0089] Under stirring conditions, 3 g of soluble phenolic resin (2123) and 0.45 g of hexamethylenetetramine curing agent were dissolved in 50 mL of ethanol to obtain a clear solution, which was transferred to a hydrothermal autoclave and sealed for polymerization at 120 ° C for 24 h. After the reaction, the filtered solid was washed with anhydrous ethanol and double distilled water and dried to obtain a polymerized powdered phenolic resin ( Figure 3 ).

[0090] At room temperature, 10 g of the prepared resin was added to a three-necked flask, 20 g of dichloroethane was added to swell for 15 min, and then 10 mL of chlorosulfonic acid was added and stirred for 4 h. After the reaction was completed, the filtered solid was washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then vacuum dried at 80 ° C to obtain a sulfonated phenolic resin powder catalyst ( Figure 4 ).

[0091] Weigh 10 g of sorbitol and add it to the autoclave reactor. After slowly heating, add 0.5 g of the sulfonated phenolic resin powder catalyst prepared above after the sorbitol melts. Pass 30 mL / min N 2 As a protective gas and to carry out water vapor, at 150 ° C, after 2 hours of reaction, sampling and analysis were performed, and the sorbitol conversion rate was measured to be 79%, the isosorbide selectivity was 85%, and the isosorbide yield was 67%.

[0092] Comparative analysis shows that the supported sulfonated phenolic resin solid acid catalyst provided by the present invention has significantly higher catalytic activity and selectivity than the unsupported sulfonated phenolic resin, which may be because the powder catalyst has fewer pore structures, resulting in a smaller specific surface area, fewer active sites, and poor catalytic performance. The supported catalyst grows in the pore structure of the solid support, so the active specific surface area of ​​the supported catalyst is much higher than that of the unsupported powder catalyst; in addition, the supported catalyst has uniform particles, high mechanical strength, easy separation and recovery, and the catalyst is not easy to lose.

[0093] Evaluation of catalyst recycling results

[0094] The catalyst prepared under the condition of hydrothermal temperature of 120°C in Example 4 was filtered after reaction, washed with anhydrous ethanol and double distilled water until the filtrate was neutral, and then dried and weighed. 50 g of sorbitol was weighed and added to the autoclave reactor. After slowly heating, the dried catalyst pellets were added after the sorbitol melted, and 30 mL / min N was passed through. 2 As a protective gas and to remove water vapor, at 150℃, 1000r / min, the reaction was carried out for 2h and then sampled and analyzed. The cycle was repeated 5 times, and the reaction results are shown in Table 6.

[0095] Table 6 Reaction results of catalysts producing isosorbide under different cycle times

[0096]

[0097] From the test results shown in Table 6, it can be seen that the supported sulfonated phenolic resin solid acid catalyst provided by the present invention is used to catalyze the dehydration of sorbitol to prepare isosorbide. The catalyst loss after 5 cycles is small, and the catalyst activity and selectivity do not show a significant decrease, so it is very suitable for recycling.

[0098] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for preparing a supported sulfonated phenolic resin solid acid catalyst, characterized in that: include: A silane coupling agent is used to hydrophobically modify the surface of the carrier to obtain a modified carrier; Then, a soluble phenolic resin and a curing agent are polymerized and grown in situ on the modified carrier to obtain a modified carrier loaded with the phenolic resin; The modified carrier loaded with phenolic resin is then subjected to sulfonation treatment to obtain the loaded sulfonated phenolic resin solid acid catalyst.

2. The preparation method according to claim 1, characterized in that: The carrier is an inorganic carrier, preferably at least one selected from SiO2, Al2O3, TiO2, and molecular sieve; And / or, the carrier is a spherical carrier; And / or, the particle size of the carrier is 1 to 5 mm.

3. The preparation method according to claim 1 or 2, characterized in that: The silane coupling agent includes at least one of trimethoxypropylsilane, trimethoxy-n-octylsilane and trimethoxy-hexadecylsilane; And / or, the curing agent includes hexamethylenetetramine.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The hydrophobic modification comprises: dispersing the carrier in a first solvent, adding the silane coupling agent at 40-80° C., stirring and reacting to obtain the modified carrier; Preferably, The first solvent includes a mixed solvent of ammonia water, anhydrous ethanol and water; And / or, the stirring reaction includes stirring at a speed of 100 to 1000 r / min for 24 to 72 hours.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the carrier to the silane coupling agent is 1:(0.025-1); And / or, the mass ratio of the carrier to the first solvent is 1:(1.5-8).

6. The preparation method according to any one of claims 1 to 5, characterized in that: The in-situ growth of polymerization using soluble phenolic resin and curing agent on the modified carrier includes: dissolving the soluble phenolic resin and curing agent in a second solvent, adding the modified carrier, and reacting for 12-72 hours under sealed conditions at 80-200° C. to obtain a modified carrier loaded with phenolic resin.

7. The preparation method according to claim 6, characterized in that: The second solvent includes at least one of methanol, ethanol, acetone, and water; And / or, the mass ratio of the phenolic resin to the modified carrier is (0.05-0.50):1, and the mass ratio of the phenolic resin to the curing agent is 10:(1-3); And / or, the mass ratio of the second solvent to the phenolic resin is (3-20):

1.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The sulfonation treatment comprises dispersing the modified carrier loaded with phenolic resin in a third solvent, adding a sulfonation reagent and stirring the reaction for 2 to 8 hours to obtain the loaded sulfonated phenolic resin solid acid catalyst; Preferably, The third solvent includes at least one of ethylene dichloride, cyclohexane, n-heptane, and toluene; And / or, the sulfonating agent includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide; And / or, the mass ratio of the modified carrier loaded with phenolic resin to the sulfonated reagent is (30-40): (1-10); And / or, the mass ratio of the modified carrier loaded with phenolic resin to the third solvent is (30-40): (60-80).

9. A supported sulfonated phenolic resin solid acid catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the supported sulfonated phenolic resin solid acid catalyst according to claim 9 in catalyzing the dehydration of sorbitol to prepare isosorbide.

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