Dow Global Technolgoies LLC

Ddp Specialty Electronic Materials Us, LLC

The Dow Chemical Company

Junqiang Liu

Janet M Goss

Edward M Calverley

Chan Han

Douglas E Beyer

Scott T Matteucci

Dean M Millar

Liren Xu

Troy D Wolford

William J Harris

H Robert Goltz

Mark K Brayden

Marcos V Martinez

Ahmad E Madkour

Matthew Lawrence Rodgers

Kurt A Koppi

Stephanie K Anderson

Steven R Lakso

Yujun Liu

Brandon J Kern

A method of forming a carbon molecular sieve membrane includes dissolving a halogenated precursor polymer in a solvent, thereby forming a dissolved halogenated precursor polymer. Homogeneously dehydrohalogenating the dissolved halogenated precursor polymer with an organic amine base to form a partially dehydrohalogenated polymer. Forming a thin film from the partially dehydrohalogenated polymer. Pyrolyzing the thin film to form the carbon molecular sieve membrane.

Method of producing carbon molecular sieve membranes

A process for preparing a microcapillary carbon molecular sieve membrane may include extruding a polyvinylidene chloride polymer to a thickness from 10 μm to 1,000 μm to form an extruded polymeric microcapillary film, wherein the extruded polymeric microcapillary film comprises a first end, a second end, and one or more microcapillaries extending from the first end to the second end; pre-treating the extruded polymeric microcapillary film at a temperature from 100° C. to 200° C. for a time from 1 hour to 48 hours to form a pre-treated polymeric microcapillary film; and pyrolizing the pre-treated polymeric microcapillary film at a temperature from 200° C. to 1,500° C. for a time from 15 minutes to 5 hours to form the microcapillary carbon molecular sieve membrane.

Methods for preparing microcapillary carbon molecular sieve membranes

A carbon molecular sieve (CMS) membrane may advantageously be made by pyrolyzing a membrane precursor composition comprised of a carbon forming polymer (e.g., polyimide) blended with a polyvinylidene chloride copolymer (PVDC), the polyvinylidene chloride copolymer being the reaction product of at least 60% to 97% by weight of vinylidene chloride and at least one other comonomer and the carbon forming polymer to polyvinylidene chloride copolymer has a weight ratio of greater than 1 to 99. The membrane precursor composition may be formed by dissolving the carbon forming polymer and PVDC in a solvent to form a dope solution. The dope solution may be shaped, for example, into an asymmetric hollow fiber. The asymmetric hollow fiber may be heated to a temperature to dehydrochorinate the PVDC and then subsequently heated in a non-oxidizing atmosphere to carbonize the polymers of the shaped membrane to form the CMS membrane.

Carbon molecular sieve membrane produced from a carbon forming polymer-polyvinylidene chloride copolymer blend

A process for separating hydrogen from a gas mixture having hydrogen and a larger gas molecule is comprised of flowing the gas mixture through a carbonized polyvinylidene chloride (PVDC) copolymer membrane having a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 GPU hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity. The carbonized PVDC copolymer may be made by heating and restraining a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 250 micrometers to a pretreatment temperature of 100° C. to 180° C. to form a pretreated polyvinylidene chloride copolymer film and then heating and restraining the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350° C. to 750° C.

Separation of gases via carbonized vinylidene chloride copolymer gas separation membranes and processes therefor

An asymmetric polyvinylidene chloride copolymer membrane is made by a method using a dope solution comprised of a polyvinylidene chloride copolymer and a solvent that solubilizes the polyvinylidene chloride copolymer that is shaped to form an initial shaped membrane. The initial shaped membrane is then quenched in a liquid comprised of a solvent that is miscible with the solvent that solubilizes the polyvinylidene chloride copolymer but is immiscible with the polyvinylidene chloride copolymer to form a wet asymmetric polyvinylidene chloride copolymer membrane. The solvents are removed from the wet membrane to form the asymmetric polyvinylidene chloride (PVDC) copolymer membrane. The membrane then may be further heated to form a carbon asymmetric membrane in which the porous support structure and separation layer of the PVDC membrane is maintained. The asymmetric carbon membrane may be useful to separate gases such as olefins from their corresponding paraffins, hydrogen from syngas or cracked gas, natural gas or refinery gas, oxygen/nitrogen, or carbon dioxide and methane.

Asymmetric polyvinylidine chloride membranes and carbon molecular sieve membranes made therefrom

A supported carbon molecular sieve (CMS) membrane is made by contacting a film of a carbon forming polymer on a polymer textile to form a laminate. The laminate is then heated to a temperature for a time under an atmosphere sufficient to carbonize the film and polymer textile to form the supported CMS membrane. The supported CMS membrane formed is a laminate having a carbon separating layer graphitically bonded to a carbon textile, wherein the carbon separating layer is a continuous film. The supported CMS membranes are particularly useful for separating gases such as olefins from their corresponding paraffins.

Supported carbon molecular sieve membranes and method to form them

A process for separating hydrogen from a gas mixture having hydrogen and a larger gas molecule is comprised of flowing the gas mixture through a carbonized polyvinylidene chloride (PVDC) copolymer membrane having a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 GPU hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity. The carbonized PVDC copolymer may be made by heating and restraining a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 250 micrometers to a pretreatment temperature of 100&#xb0; C. to 180&#xb0; C. to form a pretreated polyvinylidene chloride copolymer film and then heating and restraining the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350&#xb0; C. to 750&#xb0; C.

A carbonized PVDC copolymer useful for the separation of an olefin from its corresponding paraffin may be made by heating a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 20 micrometers to a pretreatment temperature of 100&#xb0; C. to 180&#xb0; C. to form a pretreated polyvinylidene chloride copolymer film and then heating the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350&#xb0; C. to 750&#xb0; C. A process for separating an olefin from its corresponding paraffin in a gas mixture is comprised of flowing the gas mixture through the aforementioned carbonized polyvinylidene chloride (PVDC) copolymer to produce a permeate first stream having an increased concentration of the olefin and a second retentate stream having an increased concentration of its corresponding paraffin.

A method for separating Nfrom a hydrocarbon gas mixture containing Ncomprising the steps of: i) providing a bed of adsorbent selective for N; (ii) passing the hydrocarbon gas mixture through the bed of adsorbent to at least partially remove Nfrom the gas mixture to produce: (a) N-loaded adsorbent and (b) N-depleted hydrocarbon gas mixture; iii) recovering the N-depleted hydrocarbon gas mixture; iv) regenerating the N-loaded adsorbent by at least partially removing Nfrom the adsorbent; and v) sequentially repeating steps (ii) and (iii) using regenerated adsorbent from step (iv); wherein the adsorbent comprises a pyrolized sulfonated macroporous ion exchange resin.

Separation of nitrogen from hydrocarbon gas using pyrolyzed sulfonated macroporous ion exchange resin

A process to prepare a carbon molecular sieve adsorbent composition comprises steps beginning with an activated carbon having specific effective micropore size. The activated carbon is impregnated with monomers or partially polymerized polymer, allowed to complete polymerization, and then carbonized such that the impregnant shrinks the micropores to another specific effective micropore size. Finally, the impregnated/polymerized/carbonized product is annealed at a temperature ranging from 1000&#xb0; C. to 1500&#xb0; C., which ultimately and predictably shrinks the micropores to a size ranging from 4.0 Angstroms to 4.3 Angstroms. The invention surprisingly enables fine tuning of the effective micropore size, as well as desirable selectivity, capacity and adsorption rates, to obtain highly desirable carbon molecular sieving capability particularly suited for use in, for example, fixed beds in pressure swing or temperature swing processes to enable propylene/propane separations.

Carbon molecular sieve adsorbents prepared from activated carbon and useful for propylene-propane separation

Novel carbon molecular sieve (CMS) compositions comprising carbonized vinylidene chloride copolymer having micropores with an average micropore size ranging from 3.0 to 5.0. These materials offer capability in separations of gas mixtures including, for example, propane/propylene; nitrogen/methane; and ethane/ethylene. Such may be prepared by a process wherein vinylidene chloride copolymer beads, melt extruded film or fiber are pretreated to form a precursor that is finally carbonized at high temperature. Preselection or knowledge of precursor crystallinity and attained maximum pyrolysis temperature enables preselection or knowledge of a average micropore size, according to the equation ?=6.09+(0.0275&#xd7;C)&#x2212;(0.00233&#xd7;T), wherein ? is the average micropore size in Angstroms, C is the crystallinity percentage and T is the attained maximum pyrolysis temperature in degrees Celsius, provided that crystallinity percentage ranges from 25 to 75 and temperature in degrees Celsius ranges from 800 to 1700. The beads, fibers or film may be ground, post-pyrolysis, and combined with a non-coating binder to form extruded pellets, or alternatively the fibers may be woven, either before or after pre-treatment, to form a woven fiber sheet which is thereafter pyrolyzed to form a woven fiber adsorbent.

Vinylidene chloride copolymer-based carbon molecular sieve adsorbent compositions and processes therefor

A novel microporous carbon molecular sieve may be used as the basis for carbon adsorbent pellets that have discrete areas of carbonized binder and of carbonized precursor, macropores having an average pore diameter greater than or equal to 1 micrometer and a total macroporosity of at least 30 percent, both as measured by mercury porosimetry, and micropores that are capable of selectively admitting a C2-C3 alkene and excluding a C2-C3 alkane, and a total microporosity ranging from 10 percent to 30 percent. The pellets may be prepared by pyrolyzing a pellet structure comprising a carbon forming, non-melting binder and a non-porous gel type sulfonated polystyrene precursor at a temperature ranging from 500&#xb0; C. to 1000&#xb0; C., under an inert atmosphere and other conditions suitable to form the described pellets. The pellets are particularly useful in pressure swing and temperature swing adsorption processes to separate C2-C3 alkane/alkene mixtures.

Carbon molecular sieve and pellet compositions useful for C2-C3 alkane/alkene separations

The present invention appreciates that compounds comprising nitrogen-containing moieties that are at least divalent (e.g., urea, urethane, amide, etc.) can be reacted with azides using at least radiation energy to initiate the reaction between at least a portion of the compounds and the azides to form membranes that have surprisingly high selectivities for acid gases relative to nonpolar gases such as hydrocarbons. The membranes are also resistant to COplasticization and have high acid gas flux characteristics. The resultant membranes can be extremely thin (e.g., 10 micrometers or less), which promotes high permeability for the acid gas and can translate into high productivity on a scaled-up, industrial level.

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Midland, MI, United States of America

Junqiang Liu