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WO2009064571A1 - Procédé de fabrication de tamis moléculaire fonctionnalisé par un polymère/de membranes à matrice mixte polymère - Google Patents

Procédé de fabrication de tamis moléculaire fonctionnalisé par un polymère/de membranes à matrice mixte polymère Download PDF

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Publication number
WO2009064571A1
WO2009064571A1 PCT/US2008/079922 US2008079922W WO2009064571A1 WO 2009064571 A1 WO2009064571 A1 WO 2009064571A1 US 2008079922 W US2008079922 W US 2008079922W WO 2009064571 A1 WO2009064571 A1 WO 2009064571A1
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Prior art keywords
polymer
poly
molecular sieve
alpo
mixed matrix
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Chunqing Liu
Stephen T. Wilson
David A. Lesch
Douglas B. Galloway
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Honeywell UOP LLC
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UOP LLC
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Priority claimed from US11/940,599 external-priority patent/US20090127197A1/en
Priority claimed from US11/940,539 external-priority patent/US20090131242A1/en
Priority claimed from US11/940,554 external-priority patent/US20090126570A1/en
Priority claimed from US11/940,549 external-priority patent/US20090126566A1/en
Application filed by UOP LLC filed Critical UOP LLC
Publication of WO2009064571A1 publication Critical patent/WO2009064571A1/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
    • B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0039—Inorganic membrane manufacture
    • B01D67/0041—Inorganic membrane manufacture by agglomeration of particles in the dry state
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0039—Inorganic membrane manufacture
    • B01D67/0046—Inorganic membrane manufacture by slurry techniques, e.g. die or slip-casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0079—Manufacture of membranes comprising organic and inorganic components
    • B01D67/00793—Dispersing a component, e.g. as particles or powder, in another component
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B01D69/148—Organic/inorganic mixed matrix membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/02—Inorganic material
    • B01D71/028—Molecular sieves
    • B01D71/0281—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/50—Carbon oxides
    • B01D2257/504—Carbon dioxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • B01D2325/022—Asymmetric membranes
    • B01D2325/0233—Asymmetric membranes with clearly distinguishable layers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

  • This invention pertains to a method of making polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs) with either no macrovoids or voids of less than several Angstroms at the interface of the polymer matrix and the molecular sieves. More particularly, the invention pertains to a novel method of making and methods of using polymer functionalized molecular sieve/polymer MMMs.
  • MMMs polymer functionalized molecular sieve/polymer mixed matrix membranes
  • CA cellulose acetate
  • Mixed matrix membranes have the potential to achieve higher selectivity with equal or greater permeability compared to existing polymer membranes while maintaining the advantages of low cost and easy processability.
  • Much of the research conducted to date on mixed matrix membranes has focused on the combination of a dispersed solid molecular sieving phase, such as molecular sieves or carbon molecular sieves, with an easily processed continuous polymer matrix.
  • a dispersed solid molecular sieving phase such as molecular sieves or carbon molecular sieves
  • the sieving phase in a solid/polymer mixed matrix scenario can have a selectivity that is significantly larger than that of the pure polymer.
  • Typical inorganic sieving phases in MMMs include various molecular sieves, carbon molecular sieves, and traditional silica.
  • US 2008/0141863 provided one approach to make void and defect free mixed matrix membranes.
  • polymer stabilized molecular sieves were used as the dispersed fillers and at least two different types of polymers as the continuous polymer matrix was disclosed for the first time.
  • the use of at least two different types of polymers as the continuous polymer matrix may result in phase separation between the two different types of polymers, which results in voids and defects and decreased selectivity.
  • This invention pertains to a method of making void-free and defect-free polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs).
  • MMMs novel polymer functionalized molecular sieve/polymer mixed matrix membranes
  • the present invention discloses novel polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs) with either no macrovoids or voids of less than several Angstroms at the interface of the polymer matrix and the molecular sieves by incorporating polymer (e.g., polyethersulfone) functionalized molecular sieves into a continuous polymer (e.g., polyimide) matrix.
  • polymer e.g., polyethersulfone
  • the MMMs such as PES functionalized AlPO- 14/polyimide MMMs, are manufactured in the form of symmetric dense films, asymmetric flat sheet membrane, asymmetric hollow fiber membranes or other type of structure. These MMMs have good flexibility and high mechanical strength, and exhibit significantly enhanced selectivity and/or permeability over the polymer membranes made from the corresponding continuous polymer for carbon dioxide/methane (CO 2 /CH 4 ) and hydrogen/methane (H 2 ZCH 4 ) separations as well as other separations.
  • CO 2 /CH 4 carbon dioxide/methane
  • H 2 ZCH 4 hydrogen/methane
  • the present invention provides a novel method of making polymer functionalized molecular sieve/polymer MMMs free of voids and defects, using stable polymer functionalized molecular sieve/polymer suspensions (or so-called "casting dope") containing dispersed polymer functionalized molecular sieve particles and a dissolved continuous polymer matrix in a mixture of organic solvents.
  • the method comprises the steps of : (a) first dispersing the molecular sieve particles in a mixture of two or more organic solvents by ultrasonic mixing and/or mechanical stirring or other method to form a molecular sieve slurry; (b) dissolving a suitable polymer in the molecular sieve slurry to functionalize the outer surface of the molecular sieve particles; (c) dissolving a polymer that serves as a continuous polymer matrix in the polymer functionalized molecular sieve slurry to form a stable polymer functionalized molecular sieve/polymer suspension and; (d) fabricating an MMM in a form of symmetric dense film (FIG. 1), asymmetric flat sheet (FIG. 2), or asymmetric hollow fiber using the polymer functional ized molecular sieve/polymer suspension.
  • a suitable polymer in the molecular sieve slurry to functionalize the outer surface of the molecular sieve particles
  • a later treatment step of the membrane can be added to improve selectivity but does not otherwise significantly change or damage the membrane, or cause the membrane to lose performance with time.
  • This treatment step can involve coating the top surface of the MMM with a thin layer of material such as a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, or a UV radiation curable epoxy silicone (FIG. 3).
  • a thin layer of material such as a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, or a UV radiation curable epoxy silicone (FIG. 3).
  • the molecular sieves in the MMMs provided in this invention can have selectivity and/or permeability that are significantly higher than the pure polymer membranes for separations. Addition of a small weight percent of molecular sieves to the polymer matrix, therefore, can increase the overall separation efficiency significantly.
  • the molecular sieves that are used include microporous and mesoporous molecular sieves, carbon molecular sieves, and porous metal-organic frameworks (MOFs).
  • the preferred microporous molecular sieves are selected from alumino-phosphate molecular sieves such as A1PO-18, A1PO-14,
  • A1PO-53, A1PO-52, and A1PO-17 aluminosilicate molecular sieves such as UZM-25, UZM-5 and UZM-9, silico-alumino-phosphate molecular sieves such as SAPO-34, and mixtures thereof.
  • the molecular sieve particles dispersed in the concentrated suspension are functionalized by a suitable polymer such as polyethersulfone (PES), which results in the formation of either polymer-O-molecular sieve covalent bonds via reactions between the hydroxyl (-OH) groups on the surfaces of the molecular sieves and the hydroxyl (-OH) groups at the polymer chain ends or at the polymer side chains of the molecular sieve stabilizers such as PES or hydrogen bonds between the hydroxyl groups on the surfaces of the molecular sieves and functional groups such as ether groups on the polymer chains.
  • PES polyethersulfone
  • the functionalization of the surfaces of the molecular sieves using a suitable polymer provides good compatibility and an interface substantially free of voids and defects at the molecular sieve/polymer used to functionalize the molecular sieves/polymer matrix interface. Therefore, voids and defects free polymer functionalized molecular sieve/polymer MMMs with significant separation property enhancements over traditional polymer membranes and over those prepared from suspensions containing the same polymer matrix and same molecular sieves but without polymer functionalization have been successfully prepared using these stable polymer functionalized molecular sieve/polymer suspensions.
  • MMMs fabricated using the present invention combine the solution-diffusion mechanism of polymer membrane and the molecular sieving and sorption mechanism of molecular sieves (FIG. 4), and assure maximum selectivity and consistent performance when comparing different membrane samples comprising the same molecular sieve/polymer composition.
  • the polymer used to functionalize the molecular sieve particles in the MMMs of the present invention forms good adhesion at the molecular sieve/polymer used to functionalize molecular sieves interface via hydrogen bonds or molecular sieve-O-polymer covalent bonds.
  • the polymer used to functionalize the molecular sieve particles in the MMMs is an intermediate to improve the compatibility of the molecular sieves with the continuous polymer matrix and stabilizes the molecular sieve particles in the concentrated suspensions.
  • the homogeneously suspended polymer functionalized molecular sieve particles in the suspension allow their uniform dispersion in the continuous polymer matrix of the final MMMs.
  • the MMM particularly symmetric dense film MMM, asymmetric flat sheet MMM, or asymmetric hollow fiber MMM, are fabricated from the stabilized suspension.
  • An MMM prepared by the present invention comprises uniformly dispersed polymer functionalized molecular sieve particles throughout the continuous polymer matrix.
  • the continuous polymer matrix generally is a glassy polymer such as a polyimide.
  • the polymer used to functionalize the molecular sieve particles is preferably a polymer different from the continuous polymer matrix.
  • the MMMs particularly symmetric dense film MMMs, asymmetric flat sheet MMMs, or asymmetric hollow fiber MMMs, fabricated by the method described in the current invention exhibit significantly enhanced selectivity and/or permeability over both polymer membranes prepared from the polymer matrix and over those prepared from suspensions containing the same polymer matrix and same molecular sieves but lacking polymer functionalization. This method is suitable for large scale membrane production and can be integrated into commercial polymer membrane manufacturing processes.
  • the invention also provides a process for separating at least one gas from a mixture of gases using the MMMs described in the present invention, the process comprising: (a) providing an MMM comprising a polymer functionalized molecular sieve filler material uniformly dispersed in a continuous polymer matrix which is permeable to said at least one gas; (b) contacting the mixture on one side of the MMM to cause said at least one gas to permeate the MMM; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of said at least one gas which permeated said membrane.
  • the MMMs of the present invention are suitable for a variety of liquid, gas, and vapor separations such as deep desulfurization of gasoline and diesel fuels, ethanol/water separations, pervaporation dehydration of aqueous/organic mixtures, CO 2 /CH 4 , CO 2 /N 2 , H 2 /CH 4 , O 2 /N 2 , olefin/paraffin, iso/normal paraffins separations, and other light gas mixture separations.
  • liquid, gas, and vapor separations such as deep desulfurization of gasoline and diesel fuels, ethanol/water separations, pervaporation dehydration of aqueous/organic mixtures, CO 2 /CH 4 , CO 2 /N 2 , H 2 /CH 4 , O 2 /N 2 , olefin/paraffin, iso/normal paraffins separations, and other light gas mixture separations.
  • FIG. 1 is a schematic drawing of a symmetric mixed matrix dense film containing dispersed polymer functionalized molecular sieves and a continuous polymer matrix;
  • FIG. 2 is a schematic drawing of an asymmetric mixed matrix membrane containing dispersed polymer functionalized molecular sieves and a continuous polymer matrix fabricated on a porous support substrate;
  • FIG. 3 is a schematic drawing of a post-treated asymmetric mixed matrix membrane containing dispersed polymer functionalized molecular sieves and a continuous polymer matrix fabricated on a porous support substrate and coated with a thin polymer layer;
  • FIG. 4 is a schematic drawing illustrating the separation mechanism of molecular sieve/polymer mixed matrix membranes combining the solution-diffusion mechanism of polymer membranes and the molecular sieving mechanism of molecular sieve membranes;
  • FIG. 5 is a schematic drawing showing the formation of polymer functionalized molecular sieve via covalent bonds
  • FIG. 6 is a chemical structure drawing of poly(BTDA-PMD A-TMMD A);
  • FIG. 7 is a chemical structure drawing of poly(BTDA-PMDA-ODPA-TMMDA);
  • FIG. 8 is a chemical structure drawing of poly(DSDA-TMMDA);
  • FIG. 9 is a chemical structure drawing of poly(BTD A-TMMD A);
  • FIG. 10 is a chemical structure drawing of poly(DSD A-PMD A-TMMD A);
  • FIG. 11 is a chemical structure drawing of poly(6FDA-m-PDA);
  • FIG. 12 is a chemical structure drawing of poly(6FDA-m-PDA-DABA).
  • FIG. 13 is a plot showing CO 2 /CH 4 separation performance of "control" poly(DSDA-TMMDA) and AlPO- 14/PES/poly(DSD A-TMMD A) mixed matrix dense films of the present invention at 50 0 C and 690 kPa (100 psig), as well as Robeson's 1991 polymer upper limit data for CO 2 ZCH 4 separation at 35°C and 345 kPa (50 psig).
  • FIG. 14 is a plot showing H 2 /CH 4 separation performance of "control" poly(DSDA-TMMDA) and AlPO-14/PES/poly(DSDA-TMMDA) mixed matrix dense films of the present invention at 50 0 C and 690 kPa (100 psig), as well as Robeson's 1991 polymer upper limit data for H 2 /CH 4 separation at 35°C and 345 kPa (50 psig).
  • MMM Mixed matrix membrane
  • Material compatibility and good adhesion between the polymer matrix and the molecular sieve particles are needed to achieve enhanced selectivity of the MMMs. Poor adhesion that results in voids and defects around the molecular sieve particles that are larger than the pores inside the molecular sieves decrease the overall selectivity of the MMM by allowing the gas or liquid species to bypass the pores of the molecular sieves.
  • the present invention pertains to novel void and defect free polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs). More particularly, the invention pertains to a novel method of making and methods of using these polymer functionalized molecular sieve/polymer MMMs.
  • the MMMs are prepared by using a stabilized concentrated suspension (also called “casting dope") containing uniformly dispersed polymer functionalized molecular sieves and a continuous polymer matrix.
  • the term "mixed matrix" as used in this invention means that the membrane comprises a continuous polymer matrix and discrete polymer functionalized molecular sieve particles uniformly dispersed throughout the continuous polymer matrix. Often it is a layer or layers within the membrane that is this combination of continuous polymer matrix and discrete polymer functionalized molecular sieve particles.
  • the present invention provides a method of making mixed matrix membranes (MMMs), particularly dense film MMMs, asymmetric flat sheet MMMs, or asymmetric hollow fiber MMMs, using stabilized concentrated suspensions containing dispersed polymer functionalized molecular sieve particles and a dissolved continuous polymer matrix in a mixture of organic solvents.
  • MMMs mixed matrix membranes
  • asymmetric flat sheet MMMs asymmetric flat sheet MMMs
  • asymmetric hollow fiber MMMs using stabilized concentrated suspensions containing dispersed polymer functionalized molecular sieve particles and a dissolved continuous polymer matrix in a mixture of organic solvents.
  • the method comprises: (a) dispersing the molecular sieve particles in a mixture of two or more organic solvents by ultrasonic mixing and/or mechanical stirring or other method to form a molecular sieve slurry; (b) dissolving a suitable polymer in the molecular sieve slurry to functionalize the outer surface of the molecular sieve particles; (c) dissolving a polymer that serves as a continuous polymer matrix in the polymer functionalized molecular sieve slurry to form a stable polymer functionalized molecular sieve/polymer suspension; (d) fabricating an MMM in a form of symmetric dense film (FIG. 1), asymmetric flat sheet (FIG.
  • a membrane post-treatment step can be added to improve selectivity that does not significantly change or damage the membrane, or cause the membrane to lose performance with time.
  • the membrane post-treatment step can involve coating the top surface of the MMM with a thin layer of material such as a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, or a UV radiation curable epoxy silicone to fill the surface voids and defects on the MMM (FIG. 3).
  • FIG. 4 is a schematic drawing illustrating the separation mechanism of UV cross- linked polymer coated molecular sieve/polymer mixed matrix membranes combining solution-diffusion mechanism of UV cross-linked polymer membranes and molecular sieving mechanism of molecular sieve membranes for CO 2 /CH 4 separation.
  • Line A shows the CO 2 pathway and line B shows the CH 4 pathway.
  • Selection of the appropriate MMMs containing uniformly dispersed polymer functionalized molecular sieves described herein is based on the proper selection of components including selection of molecular sieves, the polymer used to functionalize the molecular sieves, the polymer served as the continuous polymer matrix, and the solvents used to dissolve the polymers.
  • the molecular sieves in the MMMs provided in this invention can have a selectivity that is significantly higher than the pure polymer membranes for separations.
  • the molecular sieves used in the MMMs of current invention include microporous and mesoporous molecular sieves, carbon molecular sieves, and porous metal-organic frameworks (MOFs).
  • MOFs metal-organic frameworks
  • the molecular sieves need to have higher selectivity for the desired separation than the original polymer to enhance the performance of the MMM. It is preferred that the steady-state permeability of the faster permeating gas component in the molecular sieves be at least equal to that of the faster permeating gas in the original polymer matrix phase.
  • Molecular sieves have framework structures which may be characterized by distinctive wide-angle X-ray diffraction patterns. Zeolites are a subclass of molecular sieves based on an aluminosilicate composition. Non-zeolitic molecular sieves are based on other compositions such as aluminophosphates, silico-aluminophosphates, and silica.
  • Zeolites of different chemical compositions can have the same or different framework structures.
  • Zeolites can be further broadly described as molecular sieves in which complex aluminosilicate molecules assemble to define a three-dimensional framework structure enclosing cavities occupied by ions and water molecules which can move with significant freedom within the zeolite matrix. In commercially useful zeolites, the water molecules can be removed or replaced without destroying the framework structure.
  • Zeolite compositions can be represented by the following formula: M 2/n O : Al 2 O 3 : xSiOo : yH 2 O, wherein M is a cation of valence n, x is greater than or equal to 2, and y is a number determined by the porosity and the hydration state of the zeolites, generally from 0 to 8.
  • M is principally represented by Na, Ca, K, Mg and Ba in proportions usually reflecting their approximate geochemical abundance.
  • the cations are loosely bound to the structure and can frequently be completely or partially replaced with other cations or hydrogen by conventional ion exchange.
  • Acid forms of molecular sieve sorbents can be prepared by a variety of techniques including ammonium exchange followed by calcination or by direct exchange of alkali ions for protons using mineral acids or ion exchangers.
  • Microporous molecular sieve materials are microporous crystals with pores of a well-defined size ranging from 0.2 to 2 nm. This discrete porosity provides molecular sieving properties to these materials which have found wide applications as catalysts and sorption media.
  • Molecular sieve structure types can be identified by their structure type code as assigned by the IZA Structure Commission following the rules set up by the IUPAC Commission on Zeolite Nomenclature. Each unique framework topology is designated by a structure type code consisting of three capital letters.
  • compositions of such small pore alumina containing molecular sieves include non-zeolitic molecular sieves (NZMS) comprising certain aluminophosphates (AlPO's), silicoaluminophosphates (SAPO's), metallo-aluminophosphates (MeAPO's), elemental aluminophosphates (ElAPO's), metallo- silicoaluminophosphates (MeAPSO's) and elemental silicoaluminophosphates (ElAPSO's).
  • NZMS non-zeolitic molecular sieves
  • microporous molecular sieves that can be used in the present invention are small pore molecular sieves such as SAPO-34, Si-DDR, UZM-9, AlPO- 14, A1PO-34, A1PO-17, SSZ-62, SSZ-13, A1PO-18, ERS-12, CDS-I, MCM-65, MCM-47, 4A, 5A, UZM-5, UZM-9, A1PO-34, SAPO-44, SAPO-47, SAPO-17, CVX-7, SAPO-35, SAPO- 56, A1PO-52, SAPO-43, medium pore molecular sieves such as silicalite-1, and large pore molecular sieves such as NaX, NaY, and CaY.
  • small pore molecular sieves such as SAPO-34, Si-DDR, UZM-9, AlPO- 14, A1PO-34, A1PO-17, SSZ-62, SSZ-13, A1PO-18,
  • mesoporous molecular sieves having pore sizes ranging from 2 nm to 50 nm.
  • preferred mesoporous molecular sieves include MCM-41, SBA- 15, and surface functionalized MCM-41 and SBA- 15.
  • MOFs Metal-organic frameworks
  • MMMs Metal-organic frameworks
  • MOFs are a new type of highly porous crystalline zeolite-like materials and are composed of rigid organic units assembled by metal-ligands.
  • MOF-5 is a prototype of a new class of porous materials constructed from octahedral Zn-O-C clusters and benzene links.
  • Yaghi et al. reported the systematic design and construction of a series of frameworks (IRMOF) that have structures based on the skeleton of MOF-5, wherein the pore functionality and size have been varied without changing the original cubic topology.
  • IRMOF-I Zn 4 O(Ri-BDC) 3
  • MOF, IR-MOF and MOP materials allow the polymer to infiltrate the pores, improve the interfacial and mechanical properties and would in turn affect permeability. Therefore, these MOF, IR-MOF and MOP materials (all termed "MOF” herein) are used as molecular sieves in the preparation of MMMs in the present invention.
  • the particle size of the molecular sieves dispersed in the continuous polymer matrix of the MMMs in the present invention should be small enough to form a uniform dispersion of the particles in the concentrated suspensions from which the MMMs will be fabricated.
  • the median particle size should be less than 10 ⁇ m, preferably less than 5 ⁇ m, and more preferably less than 1 ⁇ m.
  • nano-molecular sieves (or "molecular sieve nanoparticles”) should be used in the MMMs of the current invention.
  • Nano-molecular sieves described herein are sub-micron size molecular sieves with particle sizes in the range of 5 to 1000 nm.
  • Nano-molecular sieve selection for the preparation of MMMs includes screening the dispersity of the nano-molecular sieves in organic solvent, the porosity, particle size, morphology, and surface functionality of the nano-molecular sieves, the adhesion or wetting property of the nano-molecular sieves with the polymer matrix.
  • Nano-molecular sieves for the preparation of MMMs should have suitable pore size to allow selective permeation of a smaller sized gas, and also should have appropriate particle size in the nanometer range to prevent defects in the membranes.
  • the nano-molecular sieves should be easily dispersed without agglomeration in the polymer matrix to maximize the transport property.
  • nano-molecular sieves described herein are usually synthesized from initially clear solutions.
  • Representative examples of nano-molecular sieves suitable to be incorporated into the MMMs described herein include Si-MFI (or silicalite-1), SAPO-34, Si-DDR, AlPO- 14, A1PO-34, AlPO- 18, AlPO- 17, A1PO-53, A1PO-52, SSZ-62, UZM-5, UZM-9, UZM-25, CDS-I, ERS- 12, MCM-65 and mixtures thereof.
  • the molecular sieve particles dispersed in the concentrated suspension from which MMMs are formed are functionalized by a suitable polymer, which results in the formation of either polymer-O-molecular sieve covalent bonds via reactions between the hydroxyl (-OH) groups on the surfaces of the molecular sieves and the hydroxyl (-OH) groups at the polymer chain ends or at the polymer side chains of the molecular sieve stabilizers such as PES (FIG. 5) or hydrogen bonds between the hydroxyl groups on the surfaces of the molecular sieves and the functional groups such as ether groups on the polymer chains.
  • a suitable polymer which results in the formation of either polymer-O-molecular sieve covalent bonds via reactions between the hydroxyl (-OH) groups on the surfaces of the molecular sieves and the hydroxyl (-OH) groups at the polymer chain ends or at the polymer side chains of the molecular sieve stabilizers such as PES (FIG. 5) or hydrogen bonds between the hydroxyl groups
  • the surfaces of the molecular sieves in the concentrated suspensions contain many hydroxyl groups attached to silicon (if present), aluminum (if present) and phosphate (if present). These hydroxyl groups on the molecular sieves in the concentrated suspensions can affect long-term stability of the suspensions and phase separation kinetics of the MMMs.
  • the stability of the concentrated suspensions refers to the molecular sieve particles remaining homogeneously dispersed in the suspension.
  • a key factor in determining whether aggregation of molecular sieve particles can be prevented and a stable suspension formed is the compatibility of these molecular sieve surfaces with the polymer matrix and the solvents in the suspensions.
  • the functional ization of the outer surfaces of the molecular sieves using a suitable polymer provides good compatibility and an interface substantially free of voids and defects at the molecular sieve/polymer used to functionalize molecular sieves/polymer matrix interface. Therefore, voids and defects free polymer functionalized molecular sieve/polymer MMMs with significant separation property enhancements over traditional polymer membranes and over those prepared from suspensions containing the same polymer matrix and same molecular sieves but without polymer functionalization have been successfully prepared using these stable polymer functionalized molecular sieve/polymer suspensions.
  • the MMMs fabricated using the present invention combine the solution-diffusion mechanism of polymer membrane and the molecular sieving and sorption mechanism of molecular sieves (FIG. 4), and assure maximum selectivity and consistent performance among different membrane samples comprising the same molecular sieve/polymer composition.
  • the functions of the polymer used to functionalize the molecular sieve particles in the MMMs of the present invention include: 1) forming good adhesion between the molecular sieve and the polymer used to functionalize molecular sieves interface via hydrogen bonds or molecular sieve-O-polymer covalent bonds; 2) being an intermediate to improve the compatibility of the molecular sieves with the continuous polymer matrix; and 3) stabilizing the molecular sieve particles in the concentrated suspensions to remain homogeneously suspended. Any polymer that has these functions can be used to functionalize the molecular sieve particles in the concentrated suspensions from which MMMs are formed.
  • the polymers used to functionalize the molecular sieves contain functional groups such as amino groups that can form hydrogen bonding with the hydroxyl groups on the surfaces of the molecular sieves. More preferably, the polymers used to functionalize the molecular sieve contain functional groups such as hydroxyl or isocyanate groups that can react with the hydroxyl groups on the surface of the molecular sieves to form polymer-O- molecular sieve or polymer-NH-CO-O-molecular sieve covalent bonds.
  • functional groups such as amino groups that can form hydrogen bonding with the hydroxyl groups on the surfaces of the molecular sieves.
  • the polymers used to functionalize the molecular sieve contain functional groups such as hydroxyl or isocyanate groups that can react with the hydroxyl groups on the surface of the molecular sieves to form polymer-O- molecular sieve or polymer-NH-CO-O-molecular sieve covalent bonds.
  • polymers are hydroxyl or amino group-terminated or ether polymers such as polyethersulfones (PESs), sulfonated PESs, polyethers such as hydroxyl group-terminated poly(ethylene oxide)s, amino group-terminated poly(ethylene oxide)s, or isocyanate group-terminated poly(ethylene oxide)s, hydroxyl group- terminated poly(propylene oxide)s, hydroxyl group-terminated co- block-poly(ethylene oxide)-poly(propylene oxide)s, hydroxyl group-terminated tri-block- poly ⁇ ropylene oxide)-block-poly(ethylene oxide)-block-poly(propylene oxide)s, tri-block- poly ⁇ ropylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2- aminopropyl ether), polyether ketones, poly(ethylene imine)s, poly(amidoamine)s, poly(vinyl alcohol)s, poly(allyl
  • the weight ratio of the molecular sieves to the polymer used to functionalize these molecular sieves can be within a broad range, but not limited to, from 1:2 to 100: 1 based on the polymer used to functionalize the molecular sieves, i.e. 50 weight parts of molecular sieve per 100 weight parts of polymer used to functionalize the molecular sieves to 100 weight parts of molecular sieve per 1 weight part of polymer used to functionalize the molecular sieves depending upon the properties sought as well as the dispersibility of a particular molecular sieves in a particular suspension.
  • the weight ratio of the molecular sieves to the polymer used to functionalize the molecular sieves in the MMMs of the current invention is in the range from 10:1 to 1:2.
  • the stabilized suspension contains polymer functional ized molecular sieve particles uniformly dispersed in the continuous polymer matrix.
  • the MMM particularly dense film MMM, asymmetric flat sheet MMM, or asymmetric hollow fiber MMM, is fabricated from the stabilized suspension.
  • the MMM prepared by the present invention comprises uniformly dispersed polymer functionalized molecular sieve particles throughout the continuous polymer matrix.
  • the polymer that serves as the continuous polymer matrix provides a wide range of properties important for separations, and modifying this polymer can improve membrane selectivity.
  • a polymer with a high glass transition temperature (Tg), high melting point, and high crystallinity is preferred for most gas separations.
  • Glassy polymers i.e., polymers below their Tg
  • a membrane fabricated from the pure polymer, which can be used as the continuous polymer matrix in MMMs exhibit a carbon dioxide over methane selectivity of at least 8, more preferably at least 15 at 5O 0 C under 690 kPa (100 psig) pure carbon dioxide or methane pressure.
  • the polymer that serves as the continuous polymer matrix is a rigid, glassy polymer.
  • the weight ratio of the molecular sieves to the polymer that serves as the continuous polymer matrix in the MMM of the current invention can be within a broad range from 1 : 100 ( 1 weight part of molecular sieves per 100 weight parts of the polymer that serves as the continuous polymer matrix) to 1:1 (100 weight parts of molecular sieves per 100 weight parts of the polymer that serves as the continuous polymer matrix) depending upon the properties sought as well as the dispersibility of the particular molecular sieves in the particular continuous polymer matrix.
  • the polymer that serves as the continuous polymer matrix in the MMM can be selected from, but is not limited to, polysulfones; sulfonated polysulfones; polyetherimides such as Ultem (or Ultem 1000) sold under the trademark Ultem®, manufactured by GE
  • Plastics such as cellulose acetate, and cellulose triacetate; polyamides; polyimides such as Matrimid sold under the trademark Matrimid® by Huntsman Advanced Materials (Matrimid® 5218 refers to a particular polyimide polymer sold under the trademark Matrimid®) and P84 or P84HT sold under the tradename P84 and P84HT respectively from HP Polymers GmbH; polyamide/imides; polyketones, polyether ketones; poly(arylene oxides) such as poly(phenylene oxide) and poly(xylene oxide); poly(esteramide- diisocyanate); polyurethanes; polyesters (including polyarylates), such as poly(ethylene terephthalate), poly(alkyl methacrylates), poly(acrylates), and poly(phenylene terephthalate); polysulfides; polymers from monomers having alpha-olefinic unsaturation in addition to those polymers previously listed including poly( ethylene), poly(propylene), poly(butylene), poly(ethylene ter
  • Typical substituents providing substituted polymers include halogens such as fluorine, chlorine and bromine; hydroxyl groups; lower alkyl groups; lower alkoxy groups; monocyclic aryl; and lower acryl groups.
  • Some preferred polymers that can serve as the continuous polymer matrix include, but are not limited to, polysulfones, sulfonated polysulfones, polyetherimides such as Ultem (or Ultem 1000) sold under the trademark Ultem®, manufactured by GE Plastics, and available from GE Polymerland, cellulosic polymers such as cellulose acetate and cellulose triacetate, polyamides; polyimides such as Matrimid sold under the trademark Matrimid® by Huntsman Advanced Materials (Matrimid® 5218 refers to a particular polyimide polymer sold under the trademark Matrimid®), P84 or P84HT sold under the trade name P84 and P84HT respectively from HP Polymers GmbH, poly(3,3',4,4'-benzophenone te
  • poly(3,3',4,4'-benzophenone tetracarboxylic dianhydride-pyromellitic dianhydride-4,4'-oxydiphthalic anhydride-3,3',5,5'-tetramethyl- 4,4' -methylene dianiline) poly(BTD A-PMD A-ODP A-TMMDA), FIG. 7
  • poly(3,3',4,4'- diphenylsulfone tetracarboxylic dianhydride-3,3',5,5'-tetramethyl-4,4'-methylene dianiline) poly(DSDA-TMMDA), FIG.
  • poly(3,3',4,4'-benzophenone tetracarboxylic dianhydride- 3, 3', 5,5 '-tetramethyl-4,4' -methylene dianiline) poly(BTDA-TMMDA), FIG. 9
  • poly(3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride-pyromellitic dianhydride- 3,3 ⁇ 5,5'-tetramethyl-4,4'-methylene dianiline) poly(DSDA-PMDA-TMMDA), FIG.
  • poly[2,2'-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-l,3-phenylenediamine] poly( ⁇ FDA-m-PDA), FIG. 11
  • poly[2,2'-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride-l,3-phenylenediamine-3,5-diaminobenzoic acid)J poly(6FDA-m- PDA-DAB A), FIG. 12
  • polyamide/imides polyketones, polyether ketones; and microporous polymers.
  • the most preferred polymers that can serve as the continuous polymer matrix include, but are not limited to, polyimides such as Matrimid®, P84®, poly(BTD A-PMDA- TMMDA), poly(BTDA-PMD A-ODPA-TMMDA), poly(DSDA-TMMDA), poly(BTDA- TMMDA), or poly(DSDA-PMD A-TMMD A), polyetherimides such as Ultem®, polysulfones, cellulose acetate, cellulose triacetate, and microporous polymers. Most preferably, the polymer that serves as the continuous polymer matrix is a polymer different from the polymer used to functionalize the molecular sieves.
  • polyimides such as Matrimid®, P84®, poly(BTD A-PMDA- TMMDA), poly(BTDA-PMD A-ODPA-TMMDA), poly(DSDA-TMMDA), poly(BTDA- TMMDA), or poly(DSDA-PMD A-TMMD A)
  • polyetherimides
  • Microporous polymers (or as so-called "polymers of intrinsic microporosity") described herein are polymeric materials that possess microporosity intrinsic to their molecular structures. See McKeown, et al., CHEM. COMMUN., 2780 (2002); Budd, et al., ADV. MATER., 16:456 (2004); McKeown, et al., CHEM. EUR. J., 11:2610 (2005). This type of microporous polymer can be used as the continuous polymer matrix in MMMs in the current invention.
  • the microporous polymers have a rigid rod-like, randomly contorted structure to generate intrinsic microporosity.
  • microporous polymers exhibit behavior analogous to that of conventional microporous molecular sieve materials, such as large and accessible surface areas, interconnected intrinsic micropores of less than 2 nm in size, as well as high chemical and thermal stability, but, in addition, possess properties of conventional polymers such as good solubility and easy processability. Moreover, these microporous polymers possess polyether polymer chains that have favorable interaction between carbon dioxide and the ethers.
  • the solvents used for dispersing the molecular sieve particles in the concentrated suspension and for dissolving the polymer used to functionalize the molecular sieves and the polymer that serves as the continuous polymer matrix are chosen primarily for their ability to completely dissolve the polymers and for ease of solvent removal in the membrane formation steps. Other considerations in the selection of solvents include low toxicity, low corrosive activity, low environmental hazard potential, availability and cost.
  • Representative solvents for use in this invention include most amide solvents that are typically used for the formation of polymeric membranes, such as N-methylpyrrolidone (NMP) and N,N-dimethyl acetamide (DMAC), methylene chloride, THF, acetone, DMF, DMSO, toluene, dioxanes, 1,3- dioxolane, and mixtures thereof, as well as others known to those skilled in the art and mixtures thereof.
  • NMP N-methylpyrrolidone
  • DMAC N,N-dimethyl acetamide
  • MMMs can be fabricated with various membrane structures such as mixed matrix dense films, asymmetric flat sheet MMMs, asymmetric thin film composite MMMs, or asymmetric hollow fiber MMMs from the stabilized concentrated suspensions containing a mixture of solvents, polymer functionalized molecular sieves, and a continuous polymer matrix.
  • the suspension can be sprayed, spin coated, poured into a sealed glass ring on top of a clean glass plate, or cast with a doctor knife.
  • a porous substrate can be dip coated with the suspension.
  • One solvent removal technique that can be used is the evaporation of volatile solvents by ventilating the atmosphere above the forming membrane with a diluent dry gas and drawing a vacuum.
  • Another solvent removal technique that can be used in making MMMs of the present invention calls for immersing the thin cast layer of the concentrated suspension (previously cast on a glass plate or on a porous or permeable substrate) in a non- solvent for the polymers but is miscible with the solvents in the suspension.
  • the substrate and/or the atmosphere or non-solvent into which the thin layer of dispersion is immersed can be heated.
  • the MMM is substantially free of solvents, it can be detached from the glass plate to form a free-standing (or self-supporting) structure or the MMM can be left in contact with a porous or permeable support substrate to form an integral composite assembly.
  • Additional fabrication steps that can be used include washing the MMM in a bath of an appropriate liquid to extract residual solvents and other foreign substances from the membrane, drying the washed MMM to remove residual liquid, and in some cases coating a thin layer of material such as a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, or a UV radiation curable epoxy silicone to fill the surface voids and defects on the MMM.
  • a thin layer of material such as a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, or a UV radiation curable epoxy silicone to fill the surface voids and defects on the MMM.
  • One preferred embodiment of the current invention is in the form of an asymmetric flat sheet MMM for gas separation comprising a smooth thin dense selective layer on top of a highly porous supporting layer.
  • the thin dense selective layer and the porous supporting layer are composed of the same polymer functionalized molecular sieve/polymer mixed matrix material.
  • the thin dense selective layer is composed of the polymer functionalized molecular sieve/polymer mixed matrix material and the porous supporting layer is composed of a pure polymer material. No major voids and defects on the top surface were observed. The back electron image (BEI) of the flat sheet asymmetric MMM showed that the polymer functionalized molecular sieve particles were uniformly distributed from the top dense layer to the porous support layer.
  • BEI back electron image
  • the method of the present invention for producing high performance MMMs is suitable for large scale membrane production and can be integrated into commercial polymer membrane manufacturing process.
  • the MMMs, particularly dense film MMMs, asymmetric flat sheet MMMs, or asymmetric hollow fiber MMMs, fabricated by the method described in the current invention exhibit significantly enhanced selectivity and/or permeability over polymer membranes prepared from their corresponding polymer matrices and over those prepared from suspensions containing the same polymer matrix and same molecular sieves but without polymer functionalization.
  • the current invention provides a process for separating at least one gas from a mixture of gases using the MMMs described in the present invention, the process comprising: (a) providing an MMM comprising a polymer functionalized molecular sieve filler material uniformly dispersed in a continuous polymer matrix which is permeable to said at least one gas; (b) contacting the mixture on one side of the MMM to cause said at least one gas to permeate the MMM; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of said at least one gas which permeated said membrane.
  • the MMMs of the present invention are suitable for a variety of gas, vapor, and liquid separations, and particularly suitable for gas and vapor separations such as separations of CO 2 /CH 4 , H 2 /CH 4 , O 2 /N 2 , CO 2 /N 2 , olefin/paraffin, and iso/normal paraffins. These MMMs are especially useful in the purification, separation or adsorption of a particular species in the liquid or gas phase. In addition to separation of pairs of gases, these MMMs may, for example, be used for the separation of proteins or other thermally unstable compounds, e.g. in the pharmaceutical and biotechnology industries.
  • the MMMs may also be used in fermenters and bioreactors to transport gases into the reaction vessel and transfer cell culture medium out of the vessel. Additionally, the MMMs may be used for the removal of microorganisms from air or water streams, water purification, and ethanol production in a continuous fermentation/membrane pervaporation system, and in detection or removal of trace compounds or metal salts in air or water streams.
  • the MMMs are especially useful in gas separation processes in air purification, petrochemical, refinery, and natural gas industries.
  • separations include separation of volatile organic compounds (such as toluene, xylene, and acetone) from an atmospheric gas, such as nitrogen or oxygen and nitrogen recovery from air.
  • Further examples of such separations are for the separation of CO 2 from natural gas, H 2 from N 2 , CH 4 , and Ar in ammonia purge gas streams, H 2 recovery in refineries, olefin/paraffin separations such as propylene/propane separation, and iso/normal paraffin separations.
  • any given pair or group of gases that differ in molecular size for example nitrogen and oxygen, carbon dioxide and methane, hydrogen and methane or carbon monoxide, helium and methane, can be separated using the MMMs described herein. More than two gases can be removed from a third gas.
  • some of the gas components which can be selectively removed from a raw natural gas using the membrane described herein include carbon dioxide, oxygen, nitrogen, water vapor, hydrogen sulfide, helium, and other trace gases.
  • Some of the gas components that can be selectively retained include hydrocarbon gases.
  • the MMMs described in the current invention are also especially useful in gas/vapor separation processes in chemical, petrochemical, pharmaceutical and allied industries for removing organic vapors from gas streams, e.g. in off-gas treatment for recovery of volatile organic compounds to meet clean air regulations, or within process streams in production plants so that valuable compounds (e.g., vinyl chloride monomer, propylene) may be recovered.
  • gas/vapor separation processes in which these MMMs may be used are hydrocarbon vapor separation from hydrogen in oil and gas refineries, for hydrocarbon dew pointing of natural gas (i.e.
  • the MMMs may incorporate a species that adsorbs strongly to certain gases (e.g. cobalt porphyrins or phthalocyanines for O 2 or silver(I) for ethane) to facilitate their transport across the membrane.
  • gases e.g. cobalt porphyrins or phthalocyanines for O 2 or silver(I) for ethane
  • MMMs may also be used in the separation of liquid mixtures by pervaporation, such as in the removal of organic compounds (e. g., alcohols, phenols, chlorinated hydrocarbons, pyridines, ketones) from water such as aqueous effluents or process fluids.
  • organic compounds e. g., alcohols, phenols, chlorinated hydrocarbons, pyridines, ketones
  • a membrane which is ethanol-selective would be used to increase the ethanol concentration in relatively dilute ethanol solutions (5-10% ethanol) obtained by fermentation processes.
  • Another liquid phase separation example using these MMMs is the deep desulphurization of gasoline and diesel fuels by a pervaporation membrane process similar to the process described in US 7,048,846, incorporated by reference herein in its entirety.
  • the MMMs that are selective to sulfur-containing molecules would be used to selectively remove sulfur-containing molecules from fluid catalytic cracking (FCC) and other naphtha hydrocarbon streams.
  • Further liquid phase examples include the separation of one organic component from another organic component, e. g. to separate isomers of organic compounds.
  • Mixtures of organic compounds which may be separated using an inventive membrane include: ethylacetate-ethanol, diethylether-ethanol, acetic acid-ethanol, benzene-ethanol, chloroform-ethanol, chloroform-methanol, acetone-isopropylether, allylalcohol-allylether, allylalcohol-cyclohexane, butanol-butylacetate, butanol-1-butylether, ethanol-ethylbutylether, propylacetate-propanol, isopropylether-isopropanol, methanol-ethanol-isopropanol, and ethylacetate-ethanol-acetic acid.
  • the MMMs may be used for separation of organic molecules from water (e.g. ethanol and/or phenol from water by pervaporation) and removal of metal and other organic compounds from water.
  • An additional application of the MMMs is in chemical reactors to enhance the yield of equilibrium-limited reactions by selective removal of a specific product in an analogous fashion to the use of hydrophilic membranes to enhance esterification yield by the removal of water.
  • the present invention pertains to novel voids and defects free polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs) fabricated from stable concentrated suspensions containing uniformly dispersed polymer functionalized molecular sieves and the continuous polymer matrix.
  • a mixed matrix membrane permits carbon dioxide to diffuse through at a faster rate than the methane in the natural gas.
  • Carbon dioxide has a higher permeation rate than methane because of higher solubility, higher diffusivity, or both.
  • carbon dioxide enriches on the permeate side of the membrane, and methane enriches on the feed (or reject) side of the membrane.
  • Any given pair of gases that differ in size for example, nitrogen and oxygen, carbon dioxide and methane, carbon dioxide and nitrogen, hydrogen and methane or carbon monoxide, helium and methane, can be separated using the MMMs described herein. More than two gases can be removed from a third gas.
  • some of the components which can be selectively removed from a raw natural gas using the membranes described herein include carbon dioxide, oxygen, nitrogen, water vapor, hydrogen sulfide, helium, and other trace gases. Some of the components that can be selectively retained include hydrocarbon gases.
  • control poly(DSDA-TMMDA) polymer dense film (abbreviated as "control” poly(DSDA-TMMDA) in Tables 1 and 2, and FIGS. 13 and 14).
  • a polyethersulfone (PES) functionalized AlPO- 14/poly(DSD A-TMMD A) mixed matrix dense film containing 10 wt-% of dispersed AlPO- 14 molecular sieve fillers in a poly(DSDA-TMMDA) polyimide continuous matrix (10% AlPO- 14/PES/poly(DSD A- TMMDA)) was prepared as follows:
  • 0.8 g of AlPO- 14 molecular sieves were dispersed in a mixture of 14.0 g of NMP and 20.6 g of 1,3-dioxolane by mechanical stirring and ultrasonication for 1 hour to form a slurry. Then 0.8 g of PES was added to functionalize AlPO- 14 molecular sieves in the slurry. The slurry was stirred for at least 1 hour to completely dissolve the PES polymer and to functionalize the outer surface of the AlPO- 14 molecular sieve.
  • poly(DSDA-TMMDA) polyimide polymer was added to the slurry and the resulting mixture was stirred for another 2 hours to form a stable casting dope containing 10 wt-% of dispersed PES functionalized AlPO- 14 molecular sieves (weight ratio of AlPO- 14 to poly(DSDA- TMMDA) and PES is 10:100; weight ratio of PES to poly(DSDA-TMMDA) is 1:9) in the continuous poly(DSDA-TMMDA) polymer matrix.
  • the stable casting dope was allowed to degas overnight.
  • a 10% AlPO- 14/PES/ ⁇ oly(DSD A-TMMDA) mixed matrix dense film was prepared on a clean glass plate from the bubble free stable casting dope using a doctor knife with a 20-mil gap. The film together with the glass plate was then put into a vacuum oven. The solvents were removed by slowly increasing the vacuum and the temperature of the vacuum oven. Finally, the dense film was dried at 200 0 C under vacuum for at least 48 hours to completely remove the residual solvents to form 10% AlPO- 14/PES/poly(DSD A- TMMDA) mixed matrix dense film (abbreviated as 10% AlPO- 14/PES/poly(DSD A- TMMDA) in Tables 1 and 2, and FIGS. 13 and 14).
  • a 40% AlPO- 14/PES/poly(DSD A-TMMDA) mixed matrix dense film (abbreviated as 40% AlPO-14/PES/poly(DSDA-TMMDA) in Tables 1 and 2, and FIGS. 13 and 14) was prepared using similar procedures as described in Example 2, but the weight ratio of A1PO-14 to poly(DSDA-TMMDA) and PES is 40:100.
  • a 50% AlPO- 14/PES/poly(DSD A-TMMD A) mixed matrix dense film (abbreviated as 50% AlPO-14/PES/poly(DSDA-TMMDA) in Tables 1 and 2, and FIGS. 13 and 14) was prepared using similar procedures as described in Example 2, but the weight ratio of AlPO- 14 to poly(DSDA-TMMDA) and PES is 50: 100.
  • a "comparative" 50% AlPO-14/poly(DSDA-TMMDA) mixed matrix dense film containing 50 wt-% of dispersed AlPO- 14 molecular sieve fillers without surface functionalization by PES in a poly(DSDA-TMMDA) polyimide continuous matrix (“comparative" 50% AlPO- 14/poly(DSDA-TMMD A)) was prepared as follows: [0085] 4.0 g of AlPO- 14 molecular sieves were dispersed in a mixture of 14.0 g of NMP and 20.6 g of 1,3-dioxolane by mechanical stirring and ultrasonication for 1 hour to form a slurry.
  • the film together with the glass plate was then put into a vacuum oven.
  • the solvents were removed by slowly increasing the vacuum and the temperature of the vacuum oven.
  • the dense film was dried at 200 0 C under vacuum for at least 48 hours to completely remove the residual solvents to form the mixed matrix dense film (abbreviated as "comparative" 50% AlPO- 14/poly(DSD A-TMMDA) in Tables 1 and 2).
  • AlPO- 14ZPESZpoly(DSD A-TMMD A) mixed matrix dense films incorporating PES functionalized AlPO- 14 molecular sieves showed a consistent increase in both Oco2/ C H4 and Pco2 for CO 2 ZCH 4 separation when AlPO- 14 loading increased from 0 ("control" poly(DSDA-TMMDA) dense film) to 0.5 (50% AlPO- 14ZPESZpoly(DSD A-
  • AlPO- 14/PES/poly(DSD A-TMMDA) mixed matrix dense films incorporating PES functional ized AlPO- 14 molecular sieves showed consistent increase in both selectivity and permeability for H 2 /CH 4 separation when AlPO- 14 loading increased from 0 ("control" poly(DSDA-TMMDA) dense film) to 0.5 (50% AlPO-14/PES/poly(DSDA- TMMDA)), demonstrating the successful combination of molecular sieving mechanism of AlPO- 14 molecular sieve fillers with the solution-diffusion mechanism of poly(DSDA- TMMDA) polyimide matrix in these MMMs for H 2 /CH4 gas separation.
  • 10% AlPO- 14/PES/poly(DSD A-TMMD A) MMM exhibited simultaneous ⁇ H2/ c H 4 increase by 20% and P H2 increase by 22% compared to the "control" poly(DSDA-TMMDA) dense film for VL 2 ICYU separation.
  • 40% AlPO-14/PES/poly(DSDA-TMMDA) MMM showed simultaneous 0C H2/ CH4 increase by 75% and P H2 increase by 82% compared to the "control" poly(DSDA-TMMDA) dense film for H 2 /CH 4 separation.
  • FIG. 14 shows H 2 /CH 4 separation performance of "control" poly(DSDA- TMMDA) and AlPO-14/PES/poly(DSDA-TMMDA) mixed matrix dense films incorporating PES functionalized AlPO- 14 with different loadings of the present invention at 50 0 C and 690 kPa (100 psig), as well as Robeson's 1991 polymer upper limit data for H 2 ZCH 4 separation at 35°C and 345 kPa (50 psig) from literature (see Robeson, J. MEMBR. SCL, 62: 165 (1991))).
  • H2/CH 4 separation performance of the "control" poly(DSDA-TMMDA) dense film is far below Robeson's 1991 polymer upper bound for H 2 /CH 4 separation.
  • the H 2 /CH 4 separation performance of 40% AlPO- 14/PES/poly(DSDA-TMMDA) MMM incorporating 40 wt-% of AlPO- 14 fillers into poly(DSD A-TMMD A) matrix was greatly improved and reached Robeson's 1991 polymer upper bound for H 2 ZCH 4 separation.
  • a poly(DSD A-TMMD A) film was cast on a non- woven fabric substrate from the bubble free casting dope using a doctor knife with a 10-mil gap.
  • the film together with the fabric substrate was gelled by immersing in a DI water bath at 0° to 5°C for 10 minutes, and then immersed in a DI water bath at 5O 0 C for another 10 minutes to remove the residual solvents and the water.
  • the resulting wet "control" poly(DSDA-TMMDA) flat sheet asymmetric polymer membrane was dried at 70° to 8O 0 C in an oven to completely remove the solvents and the water.
  • the dry "control" poly(DSDA-TMMDA) flat sheet asymmetric polymer membrane was then coated with a thermally curable silicon rubber solution (RTV615A+B Silicon Rubber from GE Silicons containing 27 wt-% RTV615A and 3 wt-% RTV615B catalyst and 70 wt-% cyclohexane solvent).
  • the RTV615A+B coated membrane was cured at 85°C for at least 2 hours in an oven to form the final "control" poly(DSDA- TMMDA) flat sheet asymmetric polymer membrane (abbreviated as Asymmetric "control" poly(DSDA-TMMDA) in Table 3).
  • a 30% AlPO- 18/PES/poly(DSD A-TMMD A) film was cast on a non- woven fabric substrate from the bubble free casting dope using a doctor knife with a 10-mil gap.
  • the film together with the fabric substrate was gelled by immersing in a DI water bath at 0° to 5 0 C for 10 minutes, and then immersed in a DI water bath at 50 0 C for another 10 minutes to remove the residual solvents and the water.
  • the resulting wet 30% AlPO- 18/PES/poly(DS DA- TMMDA) flat sheet asymmetric MMM was dried at between 70° and 8O 0 C in an oven to completely remove the solvents and the water.
  • the dry 30% AlPO- 18/PES/poly(DS DA- TMMDA) flat sheet asymmetric MMM was then coated with a thermally curable silicon rubber solution (RTV615A+B Silicon Rubber from GE Silicons) containing 27 wt-% RTV615A and 3 wt-% RTV615B catalyst and 70 wt-% cyclohexane solvent).
  • the RTV615A+B coated membrane was cured at 85°C for at least 2 hours in an oven to form the final 30% AlPO-18/PES/poly(DSDA-TMMDA) flat sheet asymmetric MMM (abbreviated as Asymmetric 30% AlPO-18/PES/poly(DSDA-TMMDA) in Table 3).
  • the surface of the molecular sieve fillers was functionalized by PES polymer via covalent bonds.
  • control poly(BTD A-PMD A-ODPA-TMMDA) in Tables 4 and 5) was prepared using similar procedures as described in Example 1, but replacing poly(DSDA- TMMDA) by poly(BTD A-PMD A-ODPA-TMMD A).
  • 30% AlPO- 14/PES/poly(BTD A-PMD A-ODPA-TMMD A) mixed matrix dense film incorporating PES functionalized AlPO- 14 molecular sieves (abbreviated as 30% AlPO- 14/PES/poly(BTDA-PMDA-ODPA-TMMDA) in Tables 4 and 5) was prepared using similar procedures as described in Example 2, but replacing poly(DSDA-TMMDA) by poly(BTDA- PMDA-ODPA-TMMDA) and the weight ratio of AlPO- 14 to poly(BTDA-PMD A-ODPA- TMMDA) and PES is 30: 100.
  • TMMDA polymer dense film prepared in Example 12 and 30% AlPO- 14ZPESZpoly(BTD A- PMDA-ODPA-TMMDA) mixed matrix dense film containing PES functionalized AlPO- 14 fillers prepared in Example 13 were measured by pure gas measurements at 50 0 C under 207 kPa (30 psig) pressure using a dense film test unit. The results are shown in Table 6.
  • a 30% UZM-25/PES/poly(DSDA-TMMDA) mixed matrix dense film incorporating PES functionalized UZM-25 molecular sieves (abbreviated as 30% UZM- 25/PES/poly(DSDA-TMMDA) in Table 7) was prepared using similar procedures as described in Example 2, but replacing AlPO- 14 by UZM-25 and the weight ratio of UZM-25 to ⁇ oly(DSDA-TMMDA) and PES is 30:100.
  • CA cellulose acetate
  • CTA cellulose triacetate
  • control CA-CTA polymer dense film (abbreviated as "control" CA-CTA in Table 8).
  • A1PO-14 molecular sieves were dispersed in a mixture of 23.5 g of 1,4- dioxane and 10.0 g of acetone by mechanical stirring and ultrasonication for 1 hour to form a slurry. Then 2.67 g of CA polymer and 5.33 g of CTA were added to the slurry together and the resulting mixture was stirred for another 3 hours to form a casting dope containing 30 wt- % of A1PO-14 molecular sieves (weight ratio of A1PO-14 to CA and CTA is 30:100; weight ratio of CA to CTA is 1 :2) in the continuous CA-CTA polymer matrix. The casting dope was allowed to degas overnight.
  • a "comparative" 30% AlPO- 14/C A-CTA mixed matrix dense film was prepared on a clean glass plate from the bubble free stable casting dope using a doctor knife with a 20- mil gap. The film together with the glass plate was then put into a vacuum oven. The solvents were removed by slowly increasing the vacuum and the temperature of the vacuum oven. Finally, the dense film was dried at 150 0 C under vacuum for at least 48 hours to completely remove the residual solvents to form "comparative" 30% AlPO- 14/C A-CTA mixed matrix dense film (abbreviated as "comparative" 30% AlPO- 14/C A-CT A in Table 8).
  • A1PO-14 molecular sieves were dispersed in a mixture of 23.5 g of 1,4- dioxane and 10.0 g of acetone by mechanical stirring and ultrasonication for 1 hour to form a slurry. Then 2.67 g of CTA polymer was added to the slurry to functionalize AlPO- 14 molecular sieves in the slurry. The slurry was stirred for at least 2 hours to completely dissolve CTA polymer and functionalize the surface of AlPO- 14. CTA was used as the surface functional izing agent to functionalize the outer surface of AlPO- 14 molecular sieves.
  • a 30% A1PO-14/CTA/CA mixed matrix dense film was prepared on a clean glass plate from the bubble free stable casting dope using a doctor knife with a 20-mil gap. The film together with the glass plate was then put into a vacuum oven. The solvents were removed by slowly increasing the vacuum and the temperature of the vacuum oven. Finally, the dense film was dried at 150 0 C under vacuum for at least 48 hours to completely remove the residual solvents to form 30% AlPO- 14/CT A/CAmixed matrix dense film (abbreviated as 30% AlPO- 14/CTA/CA in Table 8).

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  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
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Abstract

La présente invention concerne un procédé de fabrication de tamis moléculaire fonctionnalisé par un polymère/de membranes à matrice mixte polymère (MMM) n'ayant l'un comme l'autre ni macrovides ni vides inférieurs à plusieurs angströms à l'interface de la matrice polymère et des tamis moléculaires en incorporant des tamis moléculaires fonctionnalisés avec la polyéthersulfone (PES) ou le triacétate de cellulose (CTA) à l'intérieur d'une matrice polymère continue de polyimide ou d'acétate de cellulose. Les MMM, en particulier les MMM AlPO-14/polyimide fonctionnalisés avec la PES et les MMM AlPO-14/CA fonctionnalisés avec le CTA présentent une bonne flexibilité et une force mécanique élevée, et révèlent une sélectivité et/ou une perméabilité significativement améliorées par rapport aux membranes polymères fabriquées à partir des matrices polymères continues correspondantes destinées à des séparations dioxyde de carbone/méthane (CO2/CH4), hydrogène/méthane (H2/CH4), et propylène/propane. Les MMM sont appropriés pour une variété de séparations de liquides, gaz, et vapeurs.
PCT/US2008/079922 2007-11-15 2008-10-15 Procédé de fabrication de tamis moléculaire fonctionnalisé par un polymère/de membranes à matrice mixte polymère Ceased WO2009064571A1 (fr)

Applications Claiming Priority (8)

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US11/940,554 2007-11-15
US11/940,549 2007-11-15
US11/940,599 US20090127197A1 (en) 2007-11-15 2007-11-15 Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes
US11/940,539 US20090131242A1 (en) 2007-11-15 2007-11-15 Method of Making Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes
US11/940,554 US20090126570A1 (en) 2007-11-15 2007-11-15 Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes
US11/940,539 2007-11-15
US11/940,549 US20090126566A1 (en) 2007-11-15 2007-11-15 Polymer Functionalized Molecular Sieve/Polymer Mixed Matrix Membranes
US11/940,599 2007-11-15

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Cited By (11)

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Publication number Priority date Publication date Assignee Title
CN102418168A (zh) * 2011-06-02 2012-04-18 华东理工大学 多孔颗粒掺杂的聚酰亚胺中空纤维膜、其制备方法及应用
WO2012173776A3 (fr) * 2011-06-17 2013-05-23 Uop Llc Membrane de polyimide pour la séparation de gaz
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EP2564916A1 (fr) * 2011-08-30 2013-03-06 General Electric Company Systèmes et procédés permettant d'utiliser un revêtement de liaison en boehmite avec des membranes polyimides pour la séparation de gaz
EP2719445A1 (fr) 2012-10-09 2014-04-16 Clariant International Ltd. Procédé de concentration de petites molécules organiques de mélanges gazeux ou liquides à l'aide d'une membrane composite comprenant un polymère fluoré et particules siliceuses hydrophobes
WO2014056965A1 (fr) 2012-10-09 2014-04-17 Clariant International Ltd. Procédé pour concentrer au moins un produit chimique à partir de mélanges liquides ou gazeux à l'aide d'une membrane comprenant un fluoropolymère et des particules de silice hydrophobes
US9492785B2 (en) 2013-12-16 2016-11-15 Sabic Global Technologies B.V. UV and thermally treated polymeric membranes
US9522364B2 (en) 2013-12-16 2016-12-20 Sabic Global Technologies B.V. Treated mixed matrix polymeric membranes
WO2018093488A1 (fr) * 2016-11-17 2018-05-24 Uop Llc Membranes caoutchouteuses réticulées chimiquement à haute sélectivité et leur utilisation pour des séparations
CN115814623A (zh) * 2022-12-20 2023-03-21 沈阳工业大学 一种利用多元杂化体系制备混合基质膜的方法

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