Method for converting waste blended textiles into ethylene glycol and 1, 4-cyclohexanedicarboxylic acid

Abstract

The invention belongs to the technical field of recycling of waste blended textiles, and particularly discloses a method for converting waste blended textiles into ethylene glycol and 1, 4-cyclohexanedicarboxylic acid, which is characterized in that under the action of a multifunctional solid acid catalyst and H2, the waste blended textiles are simultaneously depolymerized and converted into micromolecular chemicals, and the micromolecular chemicals are recycled. Compared with an existing method for depolymerizing and utilizing a single component in the waste blended textiles, the method has the advantages that simultaneous depolymerizing and utilizing of multiple components in the waste blended textiles are achieved, the method is few in process step, high in economic benefit, simple in actual operation and environmentally friendly, the energy consumption in the waste blended textile recycling process is reduced, and the recycling cost is reduced. And meanwhile, the side reaction and subsequent separation cost is reduced, and the process economy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling waste blended textiles, and specifically discloses a method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid. Background Art

[0002] The production process of textiles consumes a lot of electricity, fuel and chemicals, and produces a lot of carbon emissions. On average, 1 kg of textiles emits 23 kg of greenhouse gases. However, most textiles are discarded after use, and the recycling rate is less than 1%. At present, the core difficulty faced by the resource utilization of waste textiles lies in the lack of efficient, environmentally friendly and low-carbon separation and reaction processes, which seriously restricts the upgrading process of the entire textile recycling industry chain. Therefore, the development of efficient purification and catalytic conversion technologies to reduce recycling and processing costs has become an urgent need to promote the upgrading of the textile recycling industry.

[0003] Patent CN 117106230 A reports a method for recovering polyester from polyester textiles. The method discloses the solvent and reaction temperature (80-240° C.) required for depolymerization of polyester textiles, and discloses a catalyst for depolymerization of polyester in polyester textiles, wherein the catalyst mainly comprises calcium hydroxide.

[0004] Patent CN 117510326 A discloses a process for concentrating depolymerization liquid for recycling waste textiles. The waste textiles are depolymerized by ethylene glycol alcoholysis, and the resulting bis(2-hydroxyethyl) terephthalate / ethylene glycol (BHET / EG) mixed liquid is concentrated, thereby increasing the BHET content in the final depolymerization liquid and solving the current problem of low regenerated DMT yield.

[0005] Patent CN 108641120 A provides a method and a recycling system for recycling waste polyester textiles. The waste polyester textiles are subjected to glycol hydrolysis reaction using zinc acetate as a catalyst, and then purified and repolymerized to obtain recycled polyester.

[0006] Patent CN 116425621 A reports a method for the mild and selective depolymerization of waste polyester and its blended textiles. The method uses waste polyester and its blended textiles as raw materials, and hydrolyzes or alcoholizes the polyester in waste polyester textiles or waste polyester blended textiles under the action of a catalyst to produce small molecular depolymerization products, while other non-polyester components do not undergo chemical changes.

[0007] In summary, many methods have been reported for the recycling of waste textiles. However, the above methods for recycling and utilizing waste textiles are aimed at polyester components in polyester clothing or mixed textiles. The purpose of separation is achieved by depolymerizing or dissolving the polyester component and retaining other components. For the non-polyester part, especially cotton, it is usually necessary to process it again (such as acetylation to prepare cellulose acetate, (Separation and Recovery of Waste Polyester-Cotton Blended Fabrics and Preparation of Cellulose Acetate [D]. Shanxi: Taiyuan University of Technology, 2019)) to achieve the full utilization of all components of waste mixed textiles. The multi-step recovery method for multiple components in waste blended textiles increases the energy consumption of the recycling process, and also increases the cost of side reactions and subsequent product separation. Therefore, we hope to provide a more efficient, green and environmentally friendly method to convert multiple components of waste blended textiles into multiple useful chemicals in a "one-pot" method. Summary of the invention

[0008] In order to solve the problems in the background technology, the present invention discloses a method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid. Under the action of a multifunctional solid acid catalyst and H2, the waste blended textiles are simultaneously depolymerized and converted into small molecule chemicals. The method has the advantages of fewer process steps, high economic benefits, simple practical operation, and green environmental protection.

[0009] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0010] The invention discloses a method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, which specifically comprises the following steps: adding blended textile fragments, a multifunctional solid acid catalyst and a reaction solution into a catalytic reactor, charging a certain amount of hydrogen, heating to a certain temperature, and starting stirring to carry out depolymerization and conversion; after the reaction is completed, the product is concentrated, crystallized and separated and purified to obtain the target product ethylene glycol and 1,4-cyclohexanedicarboxylic acid.

[0011] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the main components of the blended textiles are cotton and / or polyester, and the side length of the waste blended textiles is less than 2*2 mm.

[0012] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the blended textiles also include one or a mixture of nylon, acrylic fiber, vinylon, acetate fiber, polypropylene fiber, lyocell, polyester, and polyurethane.

[0013] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the multifunctional solid acid catalyst comprises at least one metal element and one metal oxide.

[0014] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the metal element in the multifunctional solid acid catalyst is one or a mixture of multiple elements selected from the group consisting of Pt, Ru, Ni, Cu, Fe, Pd, Ag, Ir, Rh, and Au, and the mass percentage of the metal element in the multifunctional solid acid catalyst is 0.1%-10%.

[0015] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the metal oxide in the multifunctional solid acid catalyst is Al2O3, TiO2, CrO x 、CoO x , CuO x 、ZnO、GaO x 、ZrO2、NbO x 、MgO、MoO x 、InO x SnO x 、LaO x 、CeO2、WO x 、ReO x One or more mixtures.

[0016] Furthermore, the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid is a multifunctional solid acid catalyst, and its synthesis method includes an impregnation method, a hydrothermal method, a deposition precipitation method, and a sol-gel method.

[0017] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the mass ratio of the multifunctional solid acid catalyst to the waste blended textiles is 1:1 to 1:20, preferably 1:2 to 1:10.

[0018] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the mass proportion of the waste blended textiles in the solvent is 0.1 to 100%, preferably 1 to 50%.

[0019] Furthermore, the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, wherein the solvent is a mixture of one or more of water, methanol, ethanol, isopropanol, acetonitrile, acetone, tetrahydrofuran, alkanes, cycloalkanes, dichloromethane, DMF, and DMSO.

[0020] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the H2 pressure is 1 to 100 bar, more preferably 20 to 80 bar.

[0021] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the reaction temperature is 170 to 230°C.

[0022] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the stirring rate is 500 to 1000 rpm.

[0023] Furthermore, the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid has a reaction time of 10 to 40 hours.

[0024] Furthermore, in the method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, the yield of the product ethylene glycol is >65%, the yield of the product 1,4-cyclohexanedicarboxylic acid is >90%, and the purity is >95%.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention discloses a method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid. Under the action of a multifunctional solid acid catalyst and H2, the waste blended textiles are simultaneously depolymerized and converted into small molecule chemicals. Compared with the existing method for depolymerizing and utilizing a single component in the waste blended textiles, the invention realizes the simultaneous depolymerization and utilization of multiple components of the waste blended textiles. The method of the invention has fewer process steps, high economic benefits, simple actual operation, and is green and environmentally friendly. It reduces the energy consumption in the waste blended textile recycling process, reduces the side reactions and subsequent separation costs, and improves the process economy. DETAILED DESCRIPTION

[0027] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0028] (1) Preparation of catalyst

[0029] Ir-Pd-ReO x Preparation of -Ga2O3: Iridium chloride, palladium nitrate, ammonium perrhenate, gallium trioxide and deionized water were mixed, stirred to dry at room temperature, and then dried in a 100°C oven for 12 hours. The resulting catalyst was reduced in a 350°C tubular calciner for 3 hours. Finally, it was aged in a mixture of N2:air at a ratio of 5:1 for 0.5 hours.

[0030] Ni-CuO xPreparation of -MgO-Al2O3: Nickel nitrate, copper nitrate, magnesium nitrate, aluminum nitrate and urea were dissolved in deionized water, mixed well and put into a hydrothermal kettle, and reacted in an oven at 100°C for 24 hours. The product was collected by centrifugation, washed with water and ethanol until neutral, and then dried in an oven. The white powder obtained after drying was calcined at 375°C to obtain the product.

[0031] Ru-InO x Preparation of -CeO2: Put ruthenium chloride, indium nitrate solution and cerium dioxide in a beaker and stir to dry at room temperature. Then put it in a 100℃ oven to dry for 12 hours. Reduce the obtained catalyst in a 420℃ tubular calcining furnace for 3 hours. Finally, age it in a mixed gas of N2:air with a ratio of 5:1 for 0.5 hours.

[0032] SnO x -TiO2, Au-Pt-WO x -Nb2O3 preparation methods are similar to Ru-InO x -The preparation method of CeO2 is the same.

[0033] Rh-MoO x Preparation of -La2O3: Sodium molybdate, lanthanum oxide and dilute sulfuric acid were placed in a steel autoclave lined with polytetrafluoroethylene in a beaker and heated at 200°C for 24 hours. After air cooling to room temperature, the precipitate was collected by filtration, washed with water and anhydrous ethanol, and then vacuum dried at 60°C for 5 hours. The dried sample was then transferred to a beaker containing rhodium chloride solution, stirred, and sodium borohydride solution was slowly added. The precipitate was filtered out, washed with water, and then reduced in a 500°C tube furnace for 3 hours.

[0034] Fe-CrO x -ZnO preparation method and Rh-MoO x -The preparation method of La2O3 is the same.

[0035] Ag-CoO x Preparation of -ZrO2: Dissolve zirconium isopropoxide and cobalt chloride in isopropanol solution, adjust pH with hydrochloric acid and ammonia to obtain catalyst precursor. Dry the precursor in an oven, and calcine the solid powder in air at 800℃ for 3h. Then dissolve the solid powder in silver nitrate solution, stir dry at room temperature, transfer to a tubular calcining furnace, reduce in hydrogen at 650℃ for 8h, and finally age in a mixed gas of N2:air of 5:1 for 0.5h.

[0036] (2) Reaction process

[0037] Example 1.

[0038] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, comprising: washing, drying and crushing waste blended textiles (70% cotton-30% polyester) to obtain small pieces with a side length of less than 2*2 mm. 0.85 g of waste blended textiles, 0.1 g of Ir-Pd-ReO x -Ga2O3, 50ML 25% methanol-25% tetrahydrofuran-50% water mixed solution are added to a high-pressure catalytic reactor; 8MPa H2 is charged; the temperature is raised to 185°C; the stirring rate is 800rpm; after reacting for 40 hours, it is cooled to room temperature. 1,4-cyclohexanedicarboxylic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain an ethylene glycol solution. The product composition is detected by gas chromatography and high performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 71%, the yield of 1,4-cyclohexanedicarboxylic acid is 95%, and the purity is 99%.

[0039] Example 2.

[0040] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid comprises: a blended textile sample of 90% cotton-8% polyester-2% polyurethane is chopped into small pieces with a side length of less than 2*2 mm. 2.3g of waste blended textiles, 0.45g of Ru-InO x -CeO2, 50ML 25% acetonitrile-75% water mixed solution are added to a high-pressure catalytic reactor; 6MPa H2 is charged; the temperature is raised to 225°C; the stirring rate is 800rpm; after reacting for 24 hours, it is cooled to room temperature. The terephthalic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain ethylene glycol antifreeze. The product composition is detected by gas chromatography and high performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 74%, the yield of 1,4-cyclohexanedicarboxylic acid is 93%, and the purity is 99%.

[0041] Example 3.

[0042] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, wherein the blended textile sample is 25% cotton-50% polyester-15% polypropylene-10% lyocell, which is chopped into small pieces with a side length of less than 2*2mm. The operation steps include: 1.3g of waste blended textiles, 0.26g of Rh-MoO3-La2O3 and SnO x -TiO2 (2:3), 50ML 50% ethanol-50% dichloromethane mixed solution are added to a high-pressure catalytic reactor; 4.8MPa H2 is charged; the temperature is raised to 192°C; the stirring rate is 600rpm; after reacting for 32 hours, it is cooled to room temperature. The terephthalic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain ethylene glycol antifreeze. The product composition is detected by gas chromatography and high-performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 75%, the yield of 1,4-cyclohexanedicarboxylic acid is 93%, and the purity is 98%.

[0043] Example 4.

[0044] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, wherein the blended textile sample is 70% cotton-15% polyester-15% acrylic fiber, which is chopped into small pieces with a side length of less than 2*2mm. The operation steps include: 1.8g of waste blended textiles, 0.3g of Ni-CuO x -MgO-Al2O3, 50ML 15% isopropanol-25% DMF-50% water mixed solution are added to a high-pressure catalytic reactor; 8.1MPa H2 is charged; the temperature is raised to 170°C; the stirring rate is 800rpm; after reacting for 10 hours, it is cooled to room temperature. The terephthalic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain ethylene glycol antifreeze. The product composition is detected by gas chromatography and high performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 70%, the yield of 1,4-cyclohexanedicarboxylic acid is 98%, and the purity is 98%.

[0045] Example 5.

[0046] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, wherein the blended textile sample is 50% regenerated cellulose fiber-15% polyester-35% acetate fiber, which is chopped into small pieces with a side length of less than 2*2mm. The operation steps include: 1.5g of waste blended textiles, 0.1g of waste paper, 0.5g of Fe-CrO x -ZnO and Ag-CoO x -ZrO2 (1:1), 50ML 5% DMSO-25% water-35% acetonitrile-35% acetone mixed solution are added to a high-pressure catalytic reactor; 5.5MPa H2 is charged; the temperature is raised to 230°C; the stirring rate is 1000rpm; after reacting for 15 hours, it is cooled to room temperature. The terephthalic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain ethylene glycol antifreeze. The product composition is detected by gas chromatography and high performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 65%, the yield of 1,4-cyclohexanedicarboxylic acid is 91%, and the purity is 99%.

[0047] Example 6.

[0048] A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, wherein the blended textile sample is 30% regenerated cellulose fiber-30% polyester-20% nylon-20% vinylon, which is chopped into small pieces with a side length of less than 2*2m. The operation steps include: 0.95g of waste blended textiles, 0.1g of waste PET plastic bottles, 0.33g of Au-Pt-WO x -Nb2O3, 50ML 20% methanol-30% n-propanol-30% dichloromethane-20% water mixed solution are added to a high-pressure catalytic reactor; 9.5MPa H2 is charged; the temperature is raised to 180°C; the stirring rate is 800rpm; after reacting for 15 hours, it is cooled to room temperature. The terephthalic acid is purified by recrystallization, and the liquid product is concentrated and separated to obtain ethylene glycol antifreeze. The product composition is detected by gas chromatography and high performance liquid chromatography. The yield of ethylene glycol = (ethylene glycol mole number - terephthalic acid mole number) / 3 * glucose structural unit mole number in cellulose raw material, the yield of 1,4-cyclohexanedicarboxylic acid = the mole number of 1,4-cyclohexanedicarboxylic acid in the product / the minimum repeating unit mole number in the polyester raw material. In this embodiment, the yield of ethylene glycol is 77%, the yield of 1,4-cyclohexanedicarboxylic acid is 95%, and the purity is 98%.

[0049] The above description is only an application implementation mode of the present invention, but the protection scope of the present invention is not limited to this, and the scope of rights of the present invention cannot be limited thereto. Any equivalent changes made according to the technical solution of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid, characterized in that: The method comprises the following steps: adding blended textile fragments, a multifunctional solid acid catalyst and a reaction solution into a catalytic reactor, charging a certain amount of hydrogen, heating to a certain temperature, and performing selective depolymerization and conversion under stirring; after the reaction is completed, the product is concentrated, crystallized and separated and purified to obtain the target products of ethylene glycol and 1,4-cyclohexanedicarboxylic acid.

2. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 1, characterized in that: The main components of the blended textile are cotton and / or polyester, and the side length of the blended textile fragments is less than 2*2 mm.

3. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 2, characterized in that: The blended textiles also include one or more mixtures of nylon, acrylic, vinylon, acetate, polypropylene, lyocell, polyester and polyurethane.

4. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 3, characterized in that: The multifunctional solid acid catalyst comprises at least one metal element and one metal oxide.

5. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The metal element in the multifunctional solid acid catalyst is one or a mixture of Pt, Ru, Ni, Cu, Fe, Pd, Ag, Ir, Rh, and Au, and the mass percentage of the metal element in the multifunctional solid acid catalyst is 0.1%-10%.

6. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The metal oxides in the multifunctional solid acid catalyst are Al2O3, TiO2, CrO x 、CoO x , CuO x 、ZnO、GaO x 、ZrO2、NbO x 、MgO、MoO x 、InO x SnO x 、LaO x 、CeO2、WO x 、ReO x One or more mixtures.

7. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The mass ratio of the catalyst to the waste blended textiles is 1:1 to 1:

20.

8. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The mass proportion of the waste blended textiles in the solvent is 0.1 to 100%.

9. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The solvent is one or more of water, methanol, ethanol, isopropanol, acetonitrile, acetone, tetrahydrofuran, alkane, cycloalkane, dichloromethane, DMF, and DMSO.

10. The method for converting waste blended textiles into ethylene glycol and 1,4-cyclohexanedicarboxylic acid according to claim 4, characterized in that: The reaction temperature is 170-230°C and the reaction time is 10-40h.