A method for preparing isosorbide from cotton textiles

Abstract

The application provides a method for preparing isosorbide from cotton textiles, which comprises the following steps: placing the cotton textiles and a metal catalyst in an acidic condition to perform a catalytic reaction and preparing isosorbide; the cotton textiles comprise a first component and a second component, the first component is a cellulose material, and the second component is at least one of polyethylene terephthalate, polyamide, polyurethane, polyacrylate, polylactic acid and polyvinyl chloride; wherein the acidic condition is formed by acidic substances generated in situ by depolymerization of the second component. In the application, the acidic substances such as lactic acid and terephthalic acid generated in the depolymerization process of the cotton textiles can be used as an environmentally friendly catalyst to form a catalytic system together with an additional metal catalyst. Under the synergistic catalysis of the unique acid and metal, the cellulose in the cotton textiles can be completely converted, the conversion rate is more than 99%, and the selectivity of isosorbide is not less than 78%.

Description

Technical Field

[0001] This invention belongs to the field of catalytic chemistry technology, specifically relating to a method for preparing isosorbide from cotton textiles. Background Technology

[0002] Isosorbide, as an important cellulose product, can be used not only as a novel solvent, pharmaceutical intermediate, chiral auxiliary agent, plasticizer and fuel additive, but also as a monomer for polymer materials such as polyester, and has broad application prospects.

[0003] Isosorbide can be produced from cellulose, glucose, and sorbitol as raw materials. For example, Chinese patent CN116655649A discloses a method for producing isosorbide, which includes performing a first dehydration treatment on sorbitol in the presence of a first catalyst and a protecting agent to obtain a first dehydrated product; and performing a second dehydration treatment on the first dehydrated product in the presence of a second catalyst to obtain isosorbide; wherein the first catalyst is a sulfonic acid-based ion exchange resin, and the second catalyst is different from the first catalyst. This two-step method for producing isosorbide improves the selectivity of the key intermediate product 1,4-dehydrated sorbitol (or 3,6-dehydrated sorbitol) and also increases the yield of the final product, isosorbide.

[0004] For example, Reference 1 (Isosorbide synthesis from cellulose with an efficient and recyclable)

[0005] Ruthenium catalyst [J], Green Chemistry, 2017, 19(19): 4563-4570) Isosorbide was prepared by a multi-step reaction of cellulose: cellulose was converted into sorbitol intermediate by H2SO4+Ru / C composite catalyst at 170℃ with a conversion rate of 59%. Then, the Ru / C hydrogenation catalyst was separated and reacted at 200℃ to obtain isosorbide.

[0006] However, at present, the synthesis of isosorbide mainly relies on sugars or sugar alcohols as raw materials and uses liquid acid catalysts such as concentrated sulfuric acid and hydrochloric acid, which poses problems of "competing with humans for food" and generating waste acid pollution; in addition, the yield of isosorbide is relatively low.

[0007] Waste cotton textiles are rich in cellulose, which is composed of glucose units linked by glycosidic bonds. This cellulose can be depolymerized to form sugars, which can then be selectively synthesized into sorbitol and isosorbide through further hydrogenation and dehydration. This not only replaces the current food-dependent production path that relies primarily on glucose / fructose, but also reduces the consumption of fossil fuels, significantly lowering the industry's carbon footprint. Notably, the acidic substances such as lactic acid and terephthalic acid produced during the depolymerization of waste cotton textiles can act as environmentally friendly catalysts to promote this conversion process. Therefore, using waste cotton textiles as a raw material to prepare isosorbide not only avoids competition for food resources but also achieves high-value utilization of waste, making it a green and promising technological route. Summary of the Invention

[0008] To address the aforementioned technical problems in the prior art, this invention provides a method for preparing isosorbide from cotton textiles. Using cotton textiles as raw materials, a synergistic catalytic system is formed with an added metal catalyst. Under the action of this system, the cellulose component in the textiles is efficiently and selectively converted into isosorbide.

[0009] This invention provides a method for preparing isosorbide from cotton textiles, wherein isosorbide is prepared by catalytic reaction of cotton textiles and a metal catalyst under acidic conditions; the cotton textiles include a first component and a second component, the first component being a cellulose material, and the second component being at least one of polyethylene terephthalate, polyamide, polyurethane, polyacrylate, polylactic acid, and polyvinyl chloride; wherein the acidic conditions are formed by the acidic substance generated by the in-situ depolymerization of the second component.

[0010] This invention utilizes the in-situ depolymerization of the second component in cotton textiles during the reaction process to generate acidic substances such as carboxylic acid, lactic acid, and terephthalic acid, which together with an added metal catalyst form a synergistic catalytic system. Under the action of the synergistic catalytic system, the first component in cotton textiles is efficiently and selectively converted into isosorbide.

[0011] Preferably, the cotton textiles are waste cotton textiles.

[0012] Preferably, based on the total mass of cotton textiles, the mass content of the first component is 50%-95%, and the mass content of the second component is 5%-50%.

[0013] The second component within the aforementioned mass content range can ensure the in-situ generation of sufficient acidic substances, providing a adequate acidic environment; and the first component, cellulose material within the aforementioned mass content range, can adequately supply raw materials for the preparation of isosorbide.

[0014] Preferably, the metal catalyst is prepared by loading a metal onto a support; wherein the metal is at least one of a Group VIII or Group IB metal element.

[0015] More preferably, the metal is at least one selected from ruthenium, platinum, palladium, rhodium, iron, nickel, copper, cobalt, gold, silver, and iridium.

[0016] More preferably, the carrier is at least one selected from activated carbon, alumina, silicon oxide, zinc oxide, magnesium oxide, zirconium oxide, titanium oxide, and cerium oxide.

[0017] Preferably, the amount of metal loaded on the carrier is 0.5-10 wt%.

[0018] Preferably, the mass content of the metal catalyst is 0.1%-10% based on the total mass of cotton textiles.

[0019] Preferably, the catalytic reaction is carried out in a hydrogen atmosphere with a hydrogen partial pressure of 1.0-8.0 MPa.

[0020] More preferably, the reaction temperature of the catalytic reaction is 150℃-200℃, and the reaction time is 2-8 h.

[0021] Catalytic reactions conducted within the above parameter range can effectively achieve high cellulose conversion and high selectivity for isosorbide.

[0022] Preferably, the solvent for the catalytic reaction is at least one of water, methanol, 1,4-dioxane, and tetrahydrofuran.

[0023] More preferably, the mass ratio of the solvent to the cotton textile is 2-8:1.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) This invention uses cotton textiles as raw materials to produce isosorbide, avoiding the use of grain-based sugars as raw materials. Its cost is significantly lower than that of glucose, fructose and sucrose, which not only effectively reduces production costs, but also allows for the widespread use of waste cotton textiles, realizing the resource utilization of solid waste.

[0026] (2) The acidic substances such as lactic acid and terephthalic acid produced during the depolymerization of cotton textiles can be used as environmentally friendly catalysts. Together with the added metal catalyst, they form a catalytic system. Under the unique synergistic catalytic effect of acid and metal, the cellulose in cotton textiles can be completely converted with a conversion rate of over 99%, and the selectivity of isosorbide is not less than 78%. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the method for preparing isosorbide from cotton textiles provided by the present invention. Detailed Implementation

[0028] To further illustrate the technical means and effects adopted by the present invention in order to achieve the intended purpose, the following detailed description is provided in conjunction with embodiments and comparative examples.

[0029] All raw materials were purchased from the market.

[0030] Example 1

[0031] (1) Preparation of Cu-Ni-SiO2 metal catalyst:

[0032] Accurately weigh 2.41 g Cu(NO3)2·3H2O and 2.90 g Ni(NO3)2·6H2O, dissolve them together in 80 mL of deionized water, and form a clear blue mixed salt solution under magnetic stirring. Add 10.0 g of fumed silica (SiO2, Aerosil 200) and 4.80 g of urea (CO(NH2)2) sequentially to the above solution. Stir continuously at room temperature for 2 hours to ensure uniform dispersion of the mixture. Transfer the mixed suspension to a 100 mL PTFE-lined stainless steel hydrothermal reactor, seal it, and place it in an oven. Heat to 200 °C at a heating rate of 2 °C / min and maintain this temperature for 3 hours for hydrothermal crystallization. After the hydrothermal reaction is complete, allow it to cool naturally to room temperature, then transfer the reactor to an ice-water bath for further cooling to 0 °C. Wash repeatedly with deionized water until the filtrate is neutral (pH≈7). The filter cake was placed in an oven and dried overnight (≥12 hours) at 100℃ to obtain the catalyst precursor. The dried precursor was transferred to an alumina crucible and placed in a muffle furnace. Under static air atmosphere, the temperature was increased to 550℃ at a rate of 5℃ / min and calcined at this temperature for 3 hours to completely decompose nitrates and urea, forming metal oxides. The calcined sample was transferred to a tubular reduction furnace, and high-purity hydrogen gas (flow rate 60 mL / min) was introduced. The temperature was increased to 650℃ at a rate of 3℃ / min and reduced for 1 hour. After reduction, the system was cooled to room temperature under a hydrogen atmosphere. Subsequently, the surface of the catalyst was passivated for 8 hours using a 1% O2 / Ar mixed gas (flow rate 40 mL / min) to prevent the active metal components from being violently oxidized in air. Finally, a Cu-Ni-SiO2 (containing 5.6% Cu and 5.2% Ni) metal catalyst was obtained and sealed for later use.

[0033] (2) Preparation of isosorbide:

[0034] Accurately weigh 100 g of pretreated and dried waste textiles (composition: cotton 90%, polyethylene terephthalate 8%, nylon 2%), 8.0 g of the Cu-Ni-SiO2 metal catalyst prepared in step (1), and 500 mL of deionized water, and add them together to a 2 L high-pressure reactor. Seal the reactor and start stirring (set the speed to 600 rpm). Perform three pressurization-depressurization operations on the reactor with high-pressure nitrogen to remove air from the reactor. Then, pressurize with hydrogen to an initial pressure of 5.0 MPa. Start the heating program, raise the temperature of the reaction system to 193 °C and start timing. React at this temperature for 2 h.

[0035] After the reaction is complete, the reactor is immediately cooled to room temperature using a circulating water cooling system. The reaction products are then discharged under controlled pressure using an online sampler / filter installed at the bottom of the reactor. The liquid products are collected for analysis.

[0036] (3) Product analysis:

[0037] An appropriate amount of the liquid product was filtered through a 0.22 μm aqueous microporous membrane and analyzed by high-performance liquid chromatography (HPLC). Chromatographic conditions: Shodex Sugar 1011 column; mobile phase: 5 mM H₂SO₄ aqueous solution; flow rate: 0.6 mL / min; column temperature: 60℃; detector: refractive index detector (RID). Glucose, sorbitol, 1,4-sorbitan anhydride, and the target product isosorbide in the reaction solution were qualitatively identified and quantitatively analyzed using the external standard method. Cellulose conversion rate was calculated by subtracting the mass difference. After the reaction, the solid residue was collected by filtration, thoroughly washed, dried to constant weight, and weighed.

[0038] Cellulose conversion rate (%) = (1 - residual cellulose mass / mass of cotton component in raw material) × 100%.

[0039] Isosorbide selectivity / yield is calculated based on the number of carbon moles. Isosorbide selectivity (%) = (number of carbon moles of isosorbide in the product / number of carbon moles of converted cellulose) × 100%. Isosorbide yield (%) = (number of carbon moles of isosorbide in the product / number of carbon moles of cellulose in the feedstock) × 100%.

[0040] In this embodiment, the cellulose conversion rate is >99% and the isosorbide selectivity is 91%.

[0041] Example 2

[0042] (1) Preparation of Pt-Ir-MgO-ZnO metal catalyst:

[0043] Platinum tetrachloride (H₂PtCl₆·6H₂O, containing 0.15 g of Pt), iridium chloride (IrCl₃·xH₂O, containing 0.10 g of Ir), magnesium acetate (Mg(CH₃COO)₂·4H₂O, 4.98 g), and zinc acetate (Zn(CH₃COO)₂·2H₂O, 2.20 g) were accurately weighed and dissolved together in 60 mL of deionized water, forming a homogeneous solution under magnetic stirring. The above mixed solution was placed in a rotary evaporator and concentrated under reduced pressure at a water bath temperature of 80 °C until the solution was evaporated to dryness, obtaining a viscous solid. The solid was then transferred to an oven and dried at 100 °C overnight (≥12 hours) to ensure complete removal of moisture, obtaining a catalyst precursor. The dried precursor was ground into a fine powder and placed in a muffle furnace. Under static air atmosphere, the temperature was increased to 655℃ at a rate of 5℃ / min, and calcined at this temperature for 3 hours to decompose the metal salt into the corresponding oxides and promote the formation of the MgO-ZnO solid solution on the support. The calcined sample was transferred to a tube furnace, and high-purity hydrogen gas (flow rate 50 mL / min) was introduced. The temperature was increased to 560℃ at a rate of 2℃ / min, and reduction was carried out for 5 hours. After reduction, the sample was cooled to room temperature under a hydrogen atmosphere. Subsequently, the catalyst was surface passivated for 8 hours using a 1% O2 / Ar mixed gas (flow rate 40 mL / min). The final Pt-Ir-MgO-ZnO (containing 7.5% Pt and 5.0% Ir) metal catalyst was obtained and stored in a sealed container for later use.

[0044] (2) Preparation of isosorbide:

[0045] Accurately weigh 100 g of pretreated and dried waste textiles (composition: cotton 55%, polylactic acid 30%, polyamide 15%), 5.0 g of the Pt-Ir-MgO-ZnO metal catalyst prepared in step (1), and 750 mL of 1,4-dioxane, and add them together to a 2 L high-pressure reactor. Seal the reactor and start stirring (set the speed to 550 rpm). Perform three pressurization-depressurization operations on the reactor using high-pressure nitrogen. Subsequently, introduce hydrogen to the initial pressure of 3.0 MPa. Start the heating program, raise the temperature of the reaction system to 155℃ and start timing, reacting at this temperature for 8 hours. After the reaction is completed, immediately cool the reactor to room temperature. Discharge the reaction product through a continuous sampler. Collect the liquid product for analysis.

[0046] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is >99% and the isosorbide selectivity is 86%.

[0047] Example 3

[0048] Preparation of Fe-Cu-Al2O3 metal catalyst:

[0049] Accurately weigh 4.04 g Fe(NO3)3·9H2O and 2.41 g Cu(NO3)2·3H2O, dissolve them in 50 mL of deionized water to prepare a mixed salt solution. Weigh 10.0 g γ-Al2O3 (20-40 mesh) support, and slowly add the mixed salt solution dropwise to the support while stirring, impregnating at room temperature for 12 h. Subsequently, dry the sample in an oven at 120 °C for 6 h. Transfer the dried solid to a muffle furnace, heat to 500 °C at a rate of 5 °C / min, and calcine at this temperature for 4 h. Transfer the calcined sample to a tubular reduction furnace, reduce it to 400 °C at a rate of 2 °C / min under a hydrogen atmosphere (flow rate 50 mL / min) for 3 h. After reduction, the catalyst was cooled to room temperature under H2 atmosphere, and then the surface passivation treatment was performed on the catalyst by switching to 1% O2 / Ar mixed gas (flow rate 40 mL / min) for 8 hours. The Fe-Cu-Al2O3 (containing 5.0% Fe and 5.6% Cu) catalyst was then obtained and sealed for later use.

[0050] (2) Preparation of isosorbide:

[0051] Weigh 100 g of waste textiles (70% cotton, 20% polyethylene terephthalate, 10% polyurethane), 3 g of the Fe-Cu-Al2O3 metal catalyst prepared in step (1), and 400 mL of deionized water and add them to a 1 L high-pressure reactor. Seal the reactor and purge the air inside with nitrogen three times. Then, purge with hydrogen to a pressure of 4 MPa, start stirring (500 rpm), and heat to 175 °C for 5 h. After the reaction is complete, quickly cool the reactor to room temperature, release the residual pressure, and collect the liquid product for analysis.

[0052] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is >99% and the isosorbide selectivity is 83%.

[0053] Example 4

[0054] (1) Preparation of Ru / AC metal catalyst:

[0055] Weigh out 0.52 g of RuCl3·xH3O (based on Ru content) and dissolve it in 50 mL of deionized water. Weigh out 10.0 g of granular activated carbon (AC, coconut shell carbon, 20-40 mesh) and add it to the above solution. Sonicate the solution for 2 h to ensure thorough impregnation. Then, dry the sample overnight (12 h) in an oven at 120 °C. Transfer the dried sample to a tube furnace and reduce it for 2 h at 3 °C / min under an H2 atmosphere (flow rate 50 mL / min). After reduction, cool the sample to room temperature under H2 protection. Then, switch to a 1% O2 / Ar mixed gas (flow rate 40 mL / min) for surface passivation treatment of the catalyst for 8 h to prevent the active metal components from being violently oxidized in air. Obtain the Ru / AC (containing 5% Ru) catalyst, seal and store for later use.

[0056] (2) Preparation of isosorbide:

[0057] Weigh 100 g of waste textiles (85% cotton, 10% polylactic acid, 5% polyvinyl chloride), 1.5 g of the Ru-C / AC metal catalyst prepared in step (1), and 600 mL of methanol and add them to a high-pressure reactor. Subsequent replacement, pressurization, and reaction operations are the same as in Example 3. Reaction conditions: hydrogen pressure 6 MPa, temperature 185℃, time 3 h.

[0058] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 100% and the isosorbide selectivity is 85%.

[0059] Example 5

[0060] (1) Preparation of Pd-Ag-TiO2 metal catalyst:

[0061] Accurately weigh 0.89 g of PdCl2 and 0.32 g of AgNO3, and dissolve them together in 50 mL of deionized water. Weigh 10.0 g of TiO2 (P25) support, and load the above mixed solution onto the support using an equal-volume impregnation method, allowing it to stand at room temperature for 12 h. Then, dry at 110 °C for 6 h. Calcine the dried sample in a muffle furnace at 500 °C for 3 h (heating rate 2 °C / min). Finally, reduce in a tube furnace at 300 °C for 2 h under H2 atmosphere to obtain a Pd-Ag-TiO2 (containing 4.9% Pd and 1.9% Ag) metal catalyst, which is then sealed and stored for later use.

[0062] (2) Preparation of isosorbide:

[0063] Weigh 100 g of waste textiles (60% cotton, 25% polyethylene terephthalate, 15% polyamide), 4 g of Pd-Ag-TiO2 catalyst, and 500 mL of tetrahydrofuran and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 2 MPa, temperature 165℃, time 6 h.

[0064] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 100% and the isosorbide selectivity is 80%.

[0065] Example 6

[0066] (1) Preparation of Ni-Co-ZrO2 metal catalyst:

[0067] A co-precipitation method was used. 10.46 g Ni(NO3)2·6H2O, 7.28 g Co(NO3)2·6H2O, and 65.15 g Zr(NO3)4·5H2O were weighed and dissolved in 200 mL of deionized water to prepare solution A. A 1.5 M Na2CO3 solution was prepared as precipitant B. Under vigorous stirring and a 60°C water bath, solutions A and B were added dropwise in parallel to a beaker containing 100 mL of deionized water, maintaining the pH at 9.0 ± 0.2. After the addition was complete, aging was continued for 2 h. The precipitate was filtered, washed with deionized water until neutral, and dried at 120°C for 12 h. The dried precursor was calcined in a muffle furnace at 550°C for 4 h to obtain a mixed oxide. Finally, the catalyst was reduced at 450℃ for 3 h in an H2 atmosphere, and then the surface was passivated for 8 h by switching to a 1% O2 / Ar mixed gas (flow rate 40 mL / min) to prevent the active metal components from being violently oxidized in the air, thus obtaining a Ni-Co-ZrO2 (containing 9.4% Ni and 6.6% Co) metal catalyst, which was sealed and stored for later use.

[0068] (2) Preparation of isosorbide:

[0069] Weigh 100 g of pretreated and dried waste textiles (80% cotton, 20% polyacrylate), 6 g of the Ni-Co-ZrO2 metal catalyst prepared in step (1), and 800 mL of deionized water and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 7 MPa, temperature 195℃, time 4 h.

[0070] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 100% and the isosorbide selectivity is 88%.

[0071] Example 7

[0072] (1) Preparation of Pt-Fe-MgO metal catalyst:

[0073] Accurately weigh H₂PtCl₆·6H₂O (containing 0.20 g Pt) and 1.62 g Fe(NO₃)₃·9H₂O, and dissolve them in 50 mL of deionized water. Weigh 10.0 g of MgO support, impregnate it in the above solution, and let it stand at room temperature for 12 h. Then dry it overnight at 120 °C. Calcinate the sample in a muffle furnace at 600 °C for 3 h. Finally, reduce it in a tube furnace at 400 °C for 4 h under H₂ atmosphere to obtain a Pt-Fe-MgO (containing 1.9% Pt and 2.1% Fe) metal catalyst, which is then sealed and stored for later use.

[0074] (2) Preparation of isosorbide:

[0075] Weigh 100 g of pretreated and dried waste textiles (50% cotton, 30% polyethylene terephthalate, 20% polylactic acid), 2 g of the Pt-Fe-MgO metal catalyst prepared in step (1), and 700 mL of 1,4-dioxane and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 5 MPa, temperature 170℃, time 7 h.

[0076] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 99% and the isosorbide selectivity is 93%.

[0077] Example 8

[0078] (1) Preparation of Cu-ZnO-Al2O3 metal catalyst:

[0079] A co-precipitation method was used to prepare a 1.0 M mixed salt solution by accurately weighing the appropriate amounts of Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Al(NO3)3·9H2O according to an atomic ratio of Cu:Zn:Al of 1:3:6. The mixed salt solution was then added dropwise to deionized water along with a 1.0 M Na2CO3 solution at 70 °C with constant stirring, maintaining the pH at 7.0. The precipitate was aged, filtered, washed, dried at 120 °C for 12 h, and then calcined in a muffle furnace at 500 °C for 4 h. The resulting oxide was reduced in a tube furnace at 250 °C for 5 h under a H2 atmosphere to obtain a Cu-ZnO-Al2O3 (containing 10% Cu) metal catalyst, which was then sealed and stored for later use.

[0080] (2) Preparation of isosorbide:

[0081] Weigh 100 g of pretreated and dried waste textiles (75% cotton, 15% polyethylene terephthalate, 10% polyurethane), 7 g of the Cu-ZnO-Al2O3 metal catalyst prepared in step (1), and 550 mL of deionized water and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 3 MPa, temperature 180℃, time 5 h.

[0082] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 99% and the isosorbide selectivity is 95%.

[0083] Example 9

[0084] (1) Preparation of Au-CeO2 metal catalyst:

[0085] A deposition-precipitation method was employed. 1.0 g of HAuCl4·3H2O was dissolved in 100 mL of deionized water. The pH of the HAuCl4 solution was adjusted to 8.0 using 0.1 M NaOH solution. 10.0 g of CeO2 powder was weighed and dispersed in the above solution, and stirred at 70 °C for 2 h. The mixture was filtered, thoroughly washed with deionized water until no chloride ions were detected (tested with AgNO3 solution), and then dried at 100 °C for 12 h. The dried sample was calcined at 400 °C for 2 h in static air, and then reduced at 300 °C for 2 h under H2 atmosphere to obtain Au-CeO2 (containing 4.8% Au) metal catalyst, which was then sealed and stored for later use.

[0086] (2) Preparation of isosorbide:

[0087] Weigh 100 g of pretreated and dried waste textiles (65% cotton, 25% polyamide, 10% polyvinyl chloride), 0.5 g of the Au-CeO2 metal catalyst prepared in step (1), and 450 mL of methanol and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 4 MPa, temperature 160 °C, time 8 h.

[0088] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is 99% and the isosorbide selectivity is 78%.

[0089] Example 10

[0090] (1) Preparation of Rh-Ni-SiO2 metal catalyst:

[0091] Accurately weigh RhCl3 (containing 0.10 g of Rh) and 2.90 g of Ni(NO3)2·6H2O, and dissolve them in 50 mL of deionized water. Weigh 10.0 g of SiO2 (silica gel, 10 nm pore size) support and load it using the impregnation method. After standing at room temperature for 12 h, dry at 120 °C for 6 h. Then calcine at 550 °C for 3 h in a muffle furnace. Finally, reduce in a tube furnace at 350 °C for 4 h under H2 atmosphere to obtain Rh-Ni-SiO2 (containing 1% Rh and 5.5% Ni) metal catalyst, which is sealed and stored for later use.

[0092] (2) Preparation of isosorbide:

[0093] Weigh 100 g of pretreated and dried waste textiles (90% cotton, 5% polyethylene terephthalate, 5% polylactic acid), 3 g of the Rh-Ni-SiO2 metal catalyst prepared in step (1), and 600 mL of tetrahydrofuran and add them to a high-pressure reactor. Reaction conditions: hydrogen pressure 6 MPa, temperature 190℃, time 3 h.

[0094] (3) Product analysis: The analysis process is the same as in Example 1. In this example, the cellulose conversion rate is >99% and the isosorbide selectivity is 88%.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing isosorbide from cotton textiles, characterized in that, Isosorbide was prepared by catalytically reacting cotton textiles with a metal catalyst under acidic conditions. The cotton textile comprises a first component and a second component. The first component is a cellulose material, and the second component is at least one of polyethylene terephthalate, polyamide, polyurethane, polyacrylate, polylactic acid, and polyvinyl chloride. The acidic conditions are formed by the acidic substances generated by the in-situ depolymerization of the second component. The metal catalyst is prepared by loading a metal onto a support; the metal is at least one of Group VIIIB or Group IB metal elements; the reaction temperature of the catalytic reaction is 150℃-200℃, and the reaction time is 2-8 h.

2. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, Based on the total mass of cotton textiles, the mass content of the first component is 50%-95%, and the mass content of the second component is 5%-50%.

3. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The metal is at least one of ruthenium, platinum, palladium, rhodium, iron, nickel, copper, cobalt, gold, silver, and iridium.

4. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The carrier is at least one of activated carbon, alumina, silicon oxide, zinc oxide, magnesium oxide, zirconium oxide, titanium oxide, and cerium oxide.

5. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The metal loading on the carrier is 0.5-10 wt%.

6. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The mass content of the metal catalyst is 0.1%-10% based on the total mass of cotton textiles.

7. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The catalytic reaction was carried out in a hydrogen atmosphere with a hydrogen partial pressure of 1.0-8.0 MPa.

8. The method for preparing isosorbide from cotton textiles according to claim 1, characterized in that, The solvent for the catalytic reaction is at least one of water, methanol, 1,4-dioxane, and tetrahydrofuran; the mass ratio of the solvent to the cotton textile is 2-8:1.

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