Separation method of methyl tert-butyl ether and methanol based on ultra-infiltration membrane
By introducing highly polar inducing agents and superwetting membrane technology, the molecular interaction between the porous membrane and the liquid is controlled, solving the problem of difficult separation of methyl tert-butyl ether and methanol azeotrope, and achieving a high-efficiency and low-energy separation effect.
Patent Information
- Application Number
- CN202511857186.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies struggle to efficiently separate azeotropic mixtures of methyl tert-butyl ether and methanol. Traditional separation methods are energy-intensive, complex, and costly. Existing membrane separation technologies exhibit low selectivity in separating miscible solutions with small polarity differences.
By employing superwetting membrane technology and introducing a highly polar inducing agent, the molecular interaction between the porous membrane and the liquid is controlled, achieving efficient separation of methyl tert-butyl ether and methanol. The separation is achieved by utilizing the selective permeation of the functional layer of the superwetting membrane.
High-throughput and high-efficiency separation and enrichment of methyl tert-butyl ether were achieved under low-energy conditions, simplifying the operation process and reducing energy consumption and costs.
Smart Images
Figure CN121591561A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of separation technology of miscible methyl tert-butyl ether and methanol, and in particular to a method for separating methyl tert-butyl ether and methanol based on a superwetting membrane. Background Technology
[0002] Methyl tert-butyl ether (MTBE) remains widely used in domestic and international markets due to its ability to effectively improve gasoline octane rating and combustion efficiency. With the continued growth of global gasoline consumption, the demand for MTBE, as an important additive, is also increasing. Currently, the industrial production of MTBE mainly employs a catalytic reaction process involving methanol and isobutylene. Excess methanol is often used to improve conversion rates, but this presents new separation challenges: when the methanol concentration reaches 14.3%, it forms an azeotropic mixture with MTBE, making separation difficult using conventional methods. Traditional separation processes primarily rely on extractive distillation, but this technology generally suffers from inherent limitations such as high energy consumption, complex processes, high operating costs, and difficulty in selecting the optimal extractant. In contrast, membrane separation technology, as a promising alternative, demonstrates good operating efficiency and significant energy-saving potential. In various membrane processes, membrane distillation utilizes the vapor pressure difference across a hydrophobic membrane to achieve separation, with volatile components permeating the membrane pores as vapor. However, for azeotropic systems, the relative volatility between components is close to 1, limiting separation selectivity. Reverse osmosis and nanofiltration technologies primarily rely on molecular size sieving and dissolution-diffusion mechanisms, making them suitable for separating large molecules or ions from small molecule solvents. Methyl tert-butyl ether and methanol are both small-molecule organic compounds; their size differences are insufficient for effective differentiation by commercial reverse osmosis or nanofiltration membranes. Therefore, pressure-driven membrane technologies typically exhibit low selectivity in such systems. Pervaporation technology, due to its high separation efficiency, ease of operation, continuous operation, and good economics, has achieved commercialization in areas such as azeotropic separation. However, pervaporation membranes still face challenges such as limited flux and reliance on external energy input. Superwetting membranes break through the dissolution-diffusion mechanism relied upon by traditional pervaporation, pioneering a completely new separation mode: by precisely controlling the surface properties of porous membranes, opposing Laplace pressure differences can be established between different liquids, thereby achieving spontaneous, directional transport of target components without external energy input and possessing the ability to separate immiscible solutions with high flux. However, when facing miscible solutions with minimal polarity differences, simply adjusting the surface energy of the solid membrane is insufficient to create the opposing wetting behavior necessary for selective separation. Summary of the Invention
[0003] To address the aforementioned problems, this invention provides a method for separating methyl tert-butyl ether (MTBE) and methanol based on a superwetting membrane. A universal solid-liquid synergistic superwetting membrane system is proposed, achieving efficient separation of miscible liquids by introducing a polarity inducer into the system. This system successfully achieves the effective separation of weakly miscible mixtures with slight polarity differences by precisely controlling the molecular interactions among the inducer, the miscible components, and the porous membrane. This method enables high-throughput, high-efficiency separation and enrichment of MTBE under low-energy consumption conditions.
[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for separating methyl tert-butyl ether and methanol based on a superwetting membrane, comprising the following steps: The mixture of methyl tert-butyl ether and methanol is mixed with a highly polar inducing agent and then passed through a superwetting membrane to achieve the separation of methyl tert-butyl ether and methanol. The method for preparing the superwetting membrane includes the following steps: 1) Mix polyvinylpyrrolidone, ethanol and acetic acid to obtain a mixture; 2) Mix the mixture obtained in step 1) with tetrabutyl titanate and tetraethyl orthosilicate to obtain a mixture; 3) Electrospin the mixture described in step 2) to obtain an electrospun fiber membrane; 4) Calcining the electrospun fiber membrane obtained in step 3) yields a flexible inorganic nanofiber membrane; 5) A low-polarity substance is grafted onto the surface of the flexible inorganic nanofiber membrane described in step 4) using chemical vapor deposition to obtain a superwetting membrane.
[0005] Preferably, the mass ratio of methyl tert-butyl ether to methanol is 85.7:14.3.
[0006] Preferably, the amount of the high polarity inducer is 50-80% of the total mass of the mixture.
[0007] Preferably, the highly polarity inducer includes one or more of water, ethylene glycol, and glycerol.
[0008] Preferably, the mass ratio of polyvinylpyrrolidone, ethanol and acetic acid in step 1) is 2:15:2; The mixing time is 0.5 hours.
[0009] Preferably, the mass ratio of tetrabutyl titanate, tetraethyl orthosilicate, and polyvinylpyrrolidone in step 2) is 1.5:4.5:2; The mixing time is 24 hours.
[0010] Preferably, the conditions for electrospinning in step 3) include: loading the mixture into a vertical plastic syringe equipped with a No. 20 blunt stainless steel nozzle, injecting it at a flow rate of 1 mL / h using a digital injection pump, with a nozzle-collector distance of 20 cm, establishing an electrostatic field by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV, and controlling the ambient humidity at 30% using an SZCB-300MF high-efficiency dehumidifier.
[0011] Preferably, the calcination conditions in step 4) include: a heating rate of 5°C / min, a calcination temperature of 600°C, and a calcination time of 6 hours.
[0012] Preferably, the low polarity substance in step 5) includes one or more of octadecyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and (3-chloropropyl)triethoxysilane.
[0013] Preferably, the conditions for the chemical vapor deposition method in step 5) include: plasma treatment of the superwetting film at high radio frequency power for 5 minutes in a vacuum environment, followed by a silane reaction in a closed chamber, with a silane concentration of 5.0 × 10⁻⁶. -3 The pressure is set at M, temperature 150°C, and a decompression state of 0.2 atm.
[0014] A method for separating methyl tert-butyl ether and methanol based on a superwetting membrane, the method mainly includes the following steps: (1) Introduce a highly polar inducing agent into the methyl tert-butyl ether / methanol miscible system to induce phase separation; (2) The methyl tert-butyl ether phase after phase separation is selectively permeated using an ultrawetting membrane.
[0015] In step (1), the phase separation process is achieved through a highly polar inducing agent. The highly polar inducing agent (e.g., water, ethylene glycol, glycerol, etc.) interacts strongly with the highly polar methanol in the system (e.g., hydrogen bonding, dipole-dipole interaction) to form a new highly polar phase, thereby causing the less polar methyl tert-butyl ether to precipitate out as an independent phase.
[0016] The superwetting membrane described in step (2) comprises a porous support and a selectively permeable functional layer on its surface. The functional layer has low polarity or non-polarity, enabling preferential adsorption and permeation of the methyl tert-butyl ether phase through non-polar interactions, while simultaneously blocking the highly polar methanol / inducer phase. The porous support can be a rigid inorganic material or a flexible organic material.
[0017] Furthermore, this invention also includes a specific mechanism for achieving phase separation of methyl tert-butyl ether / methanol through a highly polar inducing agent. The key lies in regulating the molecular interactions among the porous membrane, the liquid to be separated, and the inducing agent. The strength of these interactions can be determined by the polarity of each component, which can be quantified using the Hansen solubility parameter. The Hansen solubility parameter comprises three components: dispersion force, polar force, and hydrogen bonding force, which can form a "solution sphere" in three-dimensional space, characterizing the solubility range of the compound. If compound A is located within the Hansen sphere of compound B, it indicates that the two are miscible; otherwise, they are insoluble.
[0018] For methyl tert-butyl ether / methanol miscible systems, to achieve the separation of methyl tert-butyl ether from methanol, the selected inducing agent must be located within the Hansen sphere of methanol and outside the Hansen sphere of methyl tert-butyl ether. For example, the highly polar inducing agent water is only within the solubility range of methanol. After adding an appropriate amount of water, water and methanol form a new methanol / water phase, thereby promoting the precipitation of methyl tert-butyl ether and achieving phase separation.
[0019] The beneficial effects of this invention are: Compared with traditional membrane separation technologies such as pervaporation, organic solvent reverse osmosis, and evaporative permeation, this invention has advantages such as high separation flux, low energy consumption, and simple operation, and shows good application prospects in the industrial production of methyl tert-butyl ether. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.
[0021] Figure 1 This invention relates to a method for obtaining high-purity methyl tert-butyl ether based on the separation of a superwetting membrane. Detailed Implementation
[0022] This invention provides a method for separating methyl tert-butyl ether and methanol based on a superwetting membrane, comprising the following steps: The mixture of methyl tert-butyl ether and methanol is mixed with a highly polar inducing agent and then passed through a superwetting membrane to achieve the separation of methyl tert-butyl ether and methanol. The method for preparing the superwetting membrane includes the following steps: 1) Mix polyvinylpyrrolidone, ethanol and acetic acid to obtain a mixture; 2) Mix the mixture obtained in step 1) with tetrabutyl titanate and tetraethyl orthosilicate to obtain a mixture; 3) Electrospin the mixture described in step 2) to obtain an electrospun fiber membrane; 4) Calcining the electrospun fiber membrane obtained in step 3) yields a flexible inorganic nanofiber membrane; 5) A low-polarity substance is grafted onto the surface of the flexible inorganic nanofiber membrane described in step 4) using chemical vapor deposition to obtain a superwetting membrane.
[0023] In this invention, the preferred mass ratio of methyl tert-butyl ether to methanol is 85.7:14.3. In this invention, the preferred amount of the high polarity inducer is 50-80% of the total mass of the mixture. In this invention, the high polarity inducer preferably includes one or more of water, ethylene glycol, and glycerol.
[0024] In this invention, the preferred mass ratio of polyvinylpyrrolidone, ethanol and acetic acid is 2:15:2. The mixing time is preferably 0.5 h, and the mixing is carried out at room temperature. In this invention, the mass ratio of tetrabutyl titanate, tetraethyl orthosilicate, and polyvinylpyrrolidone is preferably 1.5:4.5:2; the mixing time is preferably 24 h, and the mixing is carried out at room temperature.
[0025] In this invention, the preferred conditions for electrospinning include: loading the mixture into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle, injecting it at a flow rate of 1 mL / h using a digital injection pump, maintaining a nozzle-collector distance of 20 cm, establishing an electrostatic field by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV, and controlling the ambient humidity at 30% using an SZCB-300MF high-efficiency dehumidifier. In this invention, the method for preparing the porous membrane of the superwetting separation membrane using solution electrospinning is performed according to the method in RSC Adv. 2, 992-998.
[0026] In this invention, the calcination conditions preferably include: a heating rate of 5°C / min, a calcination temperature of 600°C, and a calcination time of 6 hours. In this invention, the low-polarity substance preferably includes one or more of octadecyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and (3-chloropropyl)triethoxysilane. In this invention, the chemical vapor deposition (CVD) conditions preferably include: plasma treatment of the superwetting film at high radio frequency power for 5 minutes under vacuum (VP–RS series), followed by a silane reaction in a closed chamber, with a silane concentration of 5.0 × 10⁻⁶. -3 The chemical vapor deposition (CVD) is performed under reduced pressure conditions of M, 150°C, and 0.2 atm. In this invention, the CVD method is performed according to the method described in Bioconjugate Techniques, Academic Press, NYUSA, 2008, pp. 565–581.
[0027] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.
[0028] It should be noted that in the following embodiments of the present invention, the method for preparing the porous membrane of the superwetting separation membrane by solution electrospinning is carried out with reference to the method in RSC Adv. 2, 992-998, and therefore will not be described in detail here.
[0029] Furthermore, in the following embodiments, the vapor deposition method was performed in accordance with the method in the literature Bioconjugate Techniques, Academic Press, NYUSA, 2008, pp. 565–581, and therefore will not be described in detail here.
[0030] Example 1 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0031] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and water is used as a highly polar inducing agent. A strong polar interaction (mainly hydrogen bonding) exists between water and methanol, which can form a new methanol / water phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0032] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / water phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0033] In this embodiment, the amount of water used is 50 wt% of the total mass of the solution.
[0034] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 98.9%. Further increasing the amount of deionized water to 80 wt% can increase the purity of the obtained methyl tert-butyl ether to 99.4 wt%.
[0035] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled from the release paper, it is dried in air at 80°C overnight, followed by calcination at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2-TiO2 solid porous membrane is prepared by grafting low-polarity octadecyltrimethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0036] Example 2 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0037] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and ethylene glycol is used as a highly polar inducing agent. There is a strong polar interaction (mainly hydrogen bonding) between ethylene glycol and methanol, which can form a new methanol / ethylene glycol phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0038] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / ethylene glycol phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0039] In this embodiment, the amount of ethylene glycol used is 80 wt% of the total mass of the solution.
[0040] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 98.3%.
[0041] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled from the release paper, it is dried in air at 80°C overnight, followed by calcination at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2-TiO2 solid porous membrane is prepared by grafting low-polarity octadecyltrimethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0042] Example 3 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0043] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and glycerol is used as a highly polar inducer. There is a strong polar interaction (mainly hydrogen bonding) between glycerol and methanol, which can form a new methanol / glycerol phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0044] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / glycerol phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0045] In this embodiment, the amount of glycerol used is 80 wt% of the total mass of the solution.
[0046] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 97.8%.
[0047] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled from the release paper, it is dried in air at 80°C overnight, followed by calcination at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2-TiO2 solid porous membrane is prepared by grafting low-polarity octadecyltrimethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0048] Example 4 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0049] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and water is used as a highly polar inducing agent. A strong polar interaction (mainly hydrogen bonding) exists between water and methanol, which can form a new methanol / water phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0050] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / water phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0051] In this embodiment, the amount of water used is 50 wt% of the total mass of the solution.
[0052] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 96.1%.
[0053] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled from the release paper, it is dried in air at 80°C overnight, followed by calcination at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2-TiO2 solid porous membrane is prepared by grafting low-polarity 3-methacryloyloxypropyltrimethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0054] Example 5 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0055] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and water is used as a highly polar inducing agent. A strong polar interaction (mainly hydrogen bonding) exists between water and methanol, which can form a new methanol / water phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0056] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / water phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0057] In this embodiment, the amount of water used is 50 wt% of the total mass of the solution.
[0058] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 97.2%.
[0059] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled from the release paper, it is dried in air at 80°C overnight, followed by calcination at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2 TiO2 solid porous membrane is prepared by grafting low-polarity 1H,1H,2H,2H-perfluorodecyltrimethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0060] Example 6 This embodiment provides a method for separating methyl tert-butyl ether / methanol based on an ultrawetting separation membrane.
[0061] Step 1: In this embodiment, a methyl tert-butyl ether / methanol mixture with a mass fraction of 14.3% methanol is used as the raw material, and water is used as a highly polar inducing agent. A strong polar interaction (mainly hydrogen bonding) exists between water and methanol, which can form a new methanol / water phase, promoting the precipitation of methyl tert-butyl ether and phase separation.
[0062] Step 2: The phase-separated liquids after phase separation are separated using a superwetting membrane. The methyl tert-butyl ether phase is selectively permeated, while the methanol / water phase is blocked by the membrane, thereby achieving the separation of methyl tert-butyl ether from the miscible methyl tert-butyl ether / methanol system.
[0063] In this embodiment, the amount of water used is 50 wt% of the total mass of the solution.
[0064] In this embodiment, in step 2, the purity of the methyl tert-butyl ether phase after phase separation reaches 97.3%.
[0065] In this embodiment, the superwetting separation membrane is prepared by the following method: 2.0 g of polyvinylpyrrolidone, 15 g of ethanol, and 2.0 g of acetic acid were mixed and stirred continuously at room temperature for 0.5 hours. Then, 1.5 g of tetrabutyl titanate and 4.5 g of tetraethyl orthosilicate were added to the system, and the mixture was stirred at room temperature for 24 hours to obtain a homogeneous solution. The prepared solution was loaded into a vertical plastic syringe equipped with a No. 20 blunt-tipped stainless steel nozzle and injected using a digital syringe pump at a rate of 1 mL / h. -1Flow rate injection. The nozzle-collector distance is approximately 20 cm. An electrostatic field is established by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV. The ambient humidity is controlled at 30% using an SZCB-300MF high-efficiency dehumidifier. After the electrospun fiber membrane is peeled off from the release paper, it is dried in air at 80°C overnight, and then calcined at 600°C for 6 hours at a heating rate of 5°C / min. A flexible inorganic nanofiber membrane is finally obtained. Subsequently, a low-polarity SiO2-TiO2 solid porous membrane is prepared by grafting low-polarity (3-chloropropyl)triethoxysilane onto the membrane surface using chemical vapor deposition. This membrane exhibits superhydrophilicity to methyl tert-butyl ether and superhydrophobicity to methanol / water mixtures, thus achieving selective permeation of methyl tert-butyl ether.
[0066] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for separating methyl tert-butyl ether and methanol based on a superwetting membrane, characterized in that, Includes the following steps: The mixture of methyl tert-butyl ether and methanol is mixed with a highly polar inducing agent and then passed through a superwetting membrane to achieve the separation of methyl tert-butyl ether and methanol. The method for preparing the superwetting membrane includes the following steps: 1) Mix polyvinylpyrrolidone, ethanol and acetic acid to obtain a mixture; 2) Mix the mixture obtained in step 1) with tetrabutyl titanate and tetraethyl orthosilicate to obtain a mixture; 3) Electrospin the mixture described in step 2) to obtain an electrospun fiber membrane; 4) Calcining the electrospun fiber membrane obtained in step 3) yields a flexible inorganic nanofiber membrane; 5) A low-polarity substance is grafted onto the surface of the flexible inorganic nanofiber membrane described in step 4) using chemical vapor deposition to obtain a superwetting membrane.
2. The separation method according to claim 1, characterized in that, The mass ratio of methyl tert-butyl ether to methanol is 85.7:14.
3.
3. The separation method according to claim 1, characterized in that, The amount of the highly polar inducing agent is 50-80% of the total mass of the mixture.
4. The separation method according to claim 1 or 3, characterized in that, The highly polar inducing agent includes one or more of water, ethylene glycol, and glycerol.
5. The separation method according to claim 1, characterized in that, In step 1), the mass ratio of polyvinylpyrrolidone, ethanol, and acetic acid is 2:15:
2. The mixing time is 0.5 hours.
6. The separation method according to claim 1, characterized in that, In step 2), the mass ratio of tetrabutyl titanate, tetraethyl orthosilicate, and polyvinylpyrrolidone is 1.5:4.5:
2. The mixing time is 24 hours.
7. The separation method according to claim 1, characterized in that, Step 3) The conditions for electrospinning include: loading the mixture into a vertical plastic syringe equipped with a No. 20 blunt stainless steel nozzle, injecting it at a flow rate of 1 mL / h using a digital injection pump, with a nozzle-collector distance of 20 cm, establishing an electrostatic field by adjusting the voltage of the metal needle to +23 kV and the voltage of the rotating roller covered with aluminum foil to -2 kV, and controlling the ambient humidity at 30% using an SZCB-300MF high-efficiency dehumidifier.
8. The separation method according to claim 1, characterized in that, Step 4) The calcination conditions include: a heating rate of 5℃ / min, a calcination temperature of 600℃, and a calcination time of 6h.
9. The separation method according to claim 1, characterized in that, Step 5) The low polarity substance includes one or more of octadecyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and (3-chloropropyl)triethoxysilane.
10. The separation method according to claim 1, characterized in that, Step 5) The conditions for the chemical vapor deposition method include: plasma treatment of the superwetting film at high radio frequency power for 5 minutes in a vacuum environment, followed by a silane reaction in a closed chamber, with a silane concentration of 5.0 × 10⁻⁶. -3 M, temperature 150°C, depressurization.