Patent Description:
Poly(phenylene ether)s are commercially attractive materials because of their unique combination of physical, chemical, and electrical properties. Furthermore, the combination of poly(phenylene ether)s with other polymers or additives provides blends which result in improved overall properties including chemical resistance, high strength, and high flow. As new commercial applications are explored, various sulfonated grades of poly(phenylene ether) materials are desired.

Conventional methods for sulfonating poly(phenylene ether) develop heterogeneity with progressive levels of sulfonation, affection the reaction system making further sulfonation impossible. <CIT> discloses electrolyte membranes which provide suppressed fuel crossover and, in particular, it is therein disclosed the sulfonation of poly(<NUM>,<NUM>-diphenyl-p-phenylene oxide) using two co-solvents and sulfonic acid. However, the resulting weight ratio of the sulfonated and non-sulfonated polymers was found to be non-homogeneous, with a distribution in composition ratio being observed in the film thickness direction, thus showing heterogeneity throughout the membrane material. <CIT> relates to polymers comprising sulfonated <NUM>,<NUM>-diphenyl-<NUM>,<NUM>-phenylene oxide repeating units and their preparation method, which is based on the use of oleum as sulfonation agent. However, that particular synthetic process is cumbersome, as it involves the formation of very viscous pastes which form a pudding-like jelly ball which is difficult to handle and, additionally, a very low sulfonation level is achieved (e.g. sulfonation of <NUM> in Example <NUM>). <CIT> relates to a method for sulfonating poly(arylene oxides) with a mixture of chlorosulfonic acid and a nitroalkane, wherein a viscous semi-solid phase is formed, from which the sulfonated polymer must be isolated, thus also resulting in a cumbersome and time-consuming synthetic method. <CIT> and <CIT> both relate to sulfonated polymer electrolyte materials, but they are silent about any specific synthetic method. <CIT> relates to an electrolyte membrane production method, wherein a composite film is produced by pressure-impregnating a porous support with a thermoplastic polymer having an aromatic unit and subsequently bringing the film in contact with a solution containing a sulfonating agent.

What is needed in the art is a scalable process for sulfonating poly(phenylene ether) up to sulfonation levels of <NUM>%, and preferably with improved efficiency.

Disclosed herein are methods for sulfonating poly(phenylene ether) as defined in claim <NUM> or <NUM>.

A method for sulfonation of poly(phenylene ether) according to claim <NUM> comprises: dissolving a poly(phenylene ether) comprising <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>,<NUM>-trimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>',<NUM>,<NUM>'-tetramethyl-<NUM>,<NUM>'-dihydroxybiphenyl ether units, or a combination thereof in a mixture of <NUM>,<NUM>-dichloroethane and preferably a cosolvent to form a solvent mixture in a mixing vessel, wherein the cosolvent may comprise at least one of methyl ethyl ketone, diethyl ether, methyl ethyl sulfone, ethyl acetate, or tetramethylene sulfone; combining a sulfonating agent with the solvent mixture, wherein the sulfonating agent reacts with the poly(phenylene ether) to form sulfonated poly(phenylene ether); precipitating the sulfonated poly(phenylene ether); and filtering the precipitated sulfonated poly(phenylene ether) to form a sulfonated poly(phenylene ether) precipitate and a filtrate; wherein the sulfonated poly(phenylene ether) has a sulfonation level of <NUM> to <NUM>%.

A method for sulfonation of poly(phenylene ether) according to claim <NUM> comprises: determining the desired sulfonation level; wherein, if the desired sulfonation level is greater than <NUM>% then the method of claim <NUM> is followed and, if the sulfonation level is less than or equal to <NUM>% then poly(phenylene ether) comprising <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>,<NUM>-trimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>',<NUM>,<NUM>'-tetramethyl-<NUM>,<NUM>'-dihydroxybiphenyl ether units, or a combination thereof is dissolved in <NUM>,<NUM>-dichloroethane, preferably with no cosolvent, to form a solvent mixture in a mixing vessel; then combining a sulfonating agent with the solvent mixture, wherein the sulfonating agent reacts with the poly(phenylene ether) to form sulfonated poly(phenylene ether); precipitating the sulfonated poly(phenylene ether); and filtering the precipitated sulfonated poly(phenylene ether) to form a sulfonated poly(phenylene ether) precipitate and a filtrate.

Referring now to the drawings which are exemplary and not limiting.

Methods have been developed to reliably sulfonate of poly(phenylene ether) to degrees of sulfonation ranging from <NUM> to <NUM>%. The process is scalable and allows for the production of poly(phenylene ether) with different sulfonation levels. For example, methods enable sulfonating poly(phenylene ether) up to sulfonation levels of <NUM>%, while maintaining homogeneity, and preferably recovering and recycling the solvents. The same was achieved using reaction solvent mixtures comprising <NUM>,<NUM>-dichloroethane and a co-solvent (e.g., at least one of ethyl acetate or tetramethylene sulfone). Presence of the co-solvent enables reaction homogeneity at progressive levels of sulfonation of the polyphenylene oxide involving comparatively high stoichiometric amounts of the sulfonating agent (e.g., chloro-sulfonic acid). For example, polyphenylene oxide can be sulfonated between <NUM> to <NUM>% while maintaining a homogeneous system.

It has been determined that inhibiting precipitation during sulfonation enables the controlling of the sulfonation level. Preferably, to make this process scalable and efficient, effective handling of the effluent from the process is important. In the present methods, the solvent is recoverable and recyclable at a rate of greater than or equal to <NUM> weight percent (wt%), based upon a total weight of the solvent introduced into the system.

With the ability to efficiently produce poly(phenylene ether) with sulfonation levels of <NUM> to <NUM>%, various diverse products are possible. For example, ion exchange membranes for dialysis, proton conducting membranes for polymer electrolyte membrane fuel cells, ion exchange membranes for flow batteries, hollow fiber membranes, precursor for molecular sieve carbon membranes for gas separation, precursor for carbon electrodes for fuel cells, carbon membrane reactors, etc..

The degree of sulfonation can be controlled by adjusting an amount of solvent, and in particular, cosolvent, in the process and by the amount of sulfonating agent used. The process comprises dissolving poly(phenylene ether) in a solvent, adding a sulfonating agent to the mixture, and sulfonating the poly(phenylene ether). The solvent comprises <NUM>,<NUM>-dichloroethane. The cosolvent comprises at least one of methyl ethyl ketone, diethyl ether, methyl ethyl sulfone, ethyl acetate (EA), or tetramethylene sulfone; preferably comprises at least one of ethyl acetate, or tetramethylene sulfone, and more preferably comprises or is ethyl acetate.

Poly(phenylene ether)s include those comprising repeating structural units having the formula
<CHM>
wherein each occurrence of Z<NUM> independently comprises halogen, unsubstituted or substituted C<NUM>-C<NUM> hydrocarbyl provided that the hydrocarbyl group is not tertiary hydrocarbyl, C<NUM>-C<NUM> hydrocarbylthio, C<NUM>-C<NUM> hydrocarbyloxy, or C<NUM>-C<NUM> halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each occurrence of Z<NUM> independently comprises hydrogen, halogen, unsubstituted or substituted C<NUM>-C<NUM> hydrocarbyl provided that the hydrocarbyl group is not tertiary hydrocarbyl, C<NUM>-C<NUM> hydrocarbylthio, C<NUM>-C<NUM> hydrocarbyloxy, or C<NUM>-C<NUM> halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms. As used herein, the term "hydrocarbyl", whether used by itself, or as a prefix, suffix, or fragment of another term, refers to a residue that contains only carbon and hydrogen. The residue can be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. It can also contain combinations of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when the hydrocarbyl residue is described as substituted, it may, optionally, contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue can also contain one or more carbonyl groups, amino groups, hydroxyl groups, or the like, or it can contain heteroatoms within the backbone of the hydrocarbyl residue. As one example, Z<NUM> can be a di-n-butylaminomethyl group formed by reaction of a terminal <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenyl group with the di-n-butylamine component of an oxidative polymerization catalyst.

In some embodiments, the poly(phenylene ether) comprises <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>,<NUM>-trimethyl-<NUM>,<NUM>-phenylene ether units, or a combination thereof. In some embodiments, the poly(phenylene ether) is a poly(<NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether). In some embodiments, the poly(phenylene ether) comprises a poly(<NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether) having an intrinsic viscosity of <NUM> to <NUM> deciliter per gram (dl/g). For example, the poly(phenylene ether) can have an intrinsic viscosity of <NUM> to <NUM> dl/g, specifically <NUM> to <NUM> dl/g, more specifically <NUM> to <NUM> dl/g, even more specifically <NUM> to <NUM> dl/g, measured at <NUM> in chloroform using an Ubbelohde viscometer.

In some embodiments, the poly(phenylene ether) can comprise molecules having aminoalkyl-containing end group(s), typically located in a position ortho to the hydroxy group. Also frequently present are tetramethyldiphenoquinone (TMDQ) end groups, typically obtained from <NUM>,<NUM>-dimethylphenol-containing reaction mixtures in which tetramethyldiphenoquinone by-product is present. The poly(phenylene ether) can be in the form of a homopolymer, a copolymer, a graft copolymer, an ionomer, a block copolymer, or an oligomer as well as combinations thereof.

Poly(phenylene ether) as used herein can also refer to lower molecular weight phenylene ether oligomers. In some embodiments, the phenylene ether oligomer comprises <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>,<NUM>-trimethyl-<NUM>,<NUM>-phenylene ether units, or a combination thereof. In some embodiments, the phenylene ether oligomer can have an intrinsic viscosity of <NUM> to <NUM> deciliter per gram, or <NUM> to <NUM> deciliter per gram, or <NUM> to <NUM> deciliter per gram, measured at <NUM> in chloroform using an Ubbelohde viscometer. The phenylene ether oligomer can have a number average molecular weight of <NUM> to <NUM>,<NUM> grams per mole, and a weight average molecular weight of <NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography using polystyrene standards. In some embodiments, the number average molecular weight can be <NUM> to <NUM>,<NUM> grams per mole, and the weight average molecular weight can be <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography using polystyrene standards.

The phenylene ether oligomer can be monofunctional or bifunctional. In some embodiments, the phenylene ether oligomer can be monofunctional. For example, it can have a functional group at one terminus of the polymer chains. The functional group can be, for example, a hydroxyl group or a (meth)acrylate group, preferably a (meth)acrylate group. In some embodiments, the phenylene ether oligomer comprises poly(<NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether).

In some embodiment, the phenylene ether oligomer can be bifunctional. For example, it can have functional groups at both termini of the oligomer chain. The functional groups can be, for example, hydroxyl groups or (meth)acrylate groups, preferably (meth)acrylate groups. Bifunctional polymers with functional groups at both termini of the polymer chains are also referred to as "telechelic" polymers. In some embodiments, the phenylene ether oligomer comprises a bifunctional phenylene ether oligomer having the structure
<CHM>
wherein Q<NUM> and Q<NUM> each independently comprise halogen, unsubstituted or substituted C<NUM>-C<NUM> primary or secondary hydrocarbyl, C<NUM>-C<NUM> hydrocarbylthio, C<NUM>-C<NUM> hydrocarbyloxy, and C<NUM>-C<NUM> halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; each occurrence of Q<NUM> and Q<NUM> independently comprise hydrogen, halogen, unsubstituted or substituted C<NUM>-C<NUM> primary or secondary hydrocarbyl, C<NUM>-C<NUM> hydrocarbylthio, C<NUM>-C<NUM> hydrocarbyloxy, and C<NUM>-C<NUM> halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; Z is hydrogen or (meth)acrylate; x and y are independently <NUM> to <NUM>, specifically <NUM> to <NUM>, more specifically <NUM> to <NUM>, still more specifically <NUM> to <NUM>, even more specifically <NUM> to <NUM>, provided that the sum of x and y is at least <NUM>, specifically at least <NUM>, more specifically at least <NUM>; and L has the structure
<CHM>
wherein each occurrence of R<NUM> and R<NUM> and R<NUM> and R<NUM> independently comprises hydrogen, halogen, unsubstituted or substituted C<NUM>-C<NUM> primary or secondary hydrocarbyl, C<NUM>-C<NUM> hydrocarbylthio, C<NUM>-C<NUM> hydrocarbyloxy, and C<NUM>-C<NUM> halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; z is <NUM> or <NUM>; and Y has a structure comprising
<CHM>
wherein each occurrence of R<NUM> independently comprises hydrogen and C<NUM>-C<NUM> hydrocarbyl, and each occurrence of R<NUM> and R<NUM> independently comprises hydrogen, C<NUM>-C<NUM> hydrocarbyl, and C<NUM>-C<NUM> hydrocarbylene wherein R<NUM> and R<NUM> collectively form a C<NUM>-C<NUM> alkylene group.

In an embodiment, the phenylene ether oligomer comprises a bifunctional phenylene ether oligomer having the structure
<CHM>
wherein Q<NUM>, Q<NUM>, Q<NUM>, Q<NUM>, L, x and y are as defined above R<NUM> is methyl or hydrogen.

In the (meth)acrylate-terminated phenylene ether structure above, there are limitations on the variables x and y, which correspond to the number of phenylene ether repeating units at two different places in the bifunctional phenylene ether oligomer. In the structure, x and y are independently <NUM> to <NUM>, specifically <NUM> to <NUM>, more specifically <NUM> to <NUM>, even more specifically <NUM> to <NUM>, yet more specifically <NUM> to <NUM>. The sum of x and y is at least <NUM>, specifically at least <NUM>, more specifically at least <NUM>. A phenylene ether oligomer can be analyzed by proton nuclear magnetic resonance spectroscopy (<NUM>H NMR) to determine whether these limitations are met, on average. Specifically, <NUM>H NMR can distinguish between protons associated with internal and terminal phenylene ether groups, with internal and terminal residues of a polyhydric phenol, and with terminal residues as well. It is therefore possible to determine the average number of phenylene ether repeating units per molecule, and the relative abundance of internal and terminal residues derived from dihydric phenol.

In some embodiments the phenylene ether oligomer comprises a bifunctional phenylene ether oligomer having the structure
<CHM>
wherein each occurrence of Q<NUM> and Q<NUM> independently comprises methyl, di-n-butylaminomethyl, or morpholinomethyl; and each occurrence of a and b is independently <NUM> to <NUM>, with the proviso that the sum of a and b is at least <NUM>; and each occurrence of R<NUM> is methyl or hydrogen. An exemplary bifunctional phenylene ether oligomer includes NORYL™ Resin SA9000, available from SABIC Innovative Plastics.

In some embodiments the phenylene ether oligomer comprises a bifunctional phenylene ether oligomer having the structure
<CHM>
wherein each occurrence of Q<NUM> and Q<NUM> independently comprises methyl, di-n-butylaminomethyl, or morpholinomethyl; and each occurrence of a and b is independently <NUM> to <NUM>, with the proviso that the sum of a and b is at least <NUM>. An exemplary bifunctional phenylene ether oligomer includes NORYL™ Resin SA90, available from SABIC Innovative Plastics.

In some embodiments, the poly(phenylene ether) comprises a poly(phenylene ether) homopolymer, oligomer, or combination thereof. The poly(phenylene ether) can preferably comprise a poly(<NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether).

The poly(phenylene ether) composition can optionally further comprise one or more additives, with the proviso that the one or more additives do not significantly adversely affect one or more desirable properties of the poly(phenylene ether) composition). Exemplary additives can include stabilizers, mold release agents, lubricants, processing aids, drip retardants, nucleating agents, UV blockers, dyes, pigments, antioxidants, anti-static agents, blowing agents, mineral oil, metal deactivators, antiblocking agents, and combinations thereof. When present, such additives are typically used in a total amount of less than or equal to <NUM> weight percent, specifically less than or equal to <NUM> weight percent, based on the total weight of the poly(phenylene ether) composition.

The process for the sulfonation of the poly(phenylene ether) comprises dissolving the poly(phenylene ether) in a solvent (preferably in a solvent and cosolvent) to form a solvent mixture. The mixing can be performed at temperatures of <NUM> to <NUM>, e.g., <NUM> to <NUM>. The <NUM>,<NUM>-dichloroethane is present in a sufficient quantity to dissolve the poly(phenylene ether). The amount of cosolvent is sufficient to prevent precipitation of the sulfonated poly(phenylene ether) before the desired degree of sulfonation has been attained. The solvent mixture can comprise <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt%, poly(phenylene ether); <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt% <NUM>,<NUM>-dichloroethane; and, <NUM> to <NUM> wt% (e.g., greater than zero), preferably greater than <NUM> to <NUM> wt%, cosolvent; based upon <NUM> wt% weight of the solvent mixture. The solvent mixture can comprise <NUM> to <NUM> wt% of the poly(phenylene ether); <NUM> to <NUM> wt% of the <NUM>,<NUM>-dichloroethane; and <NUM> to <NUM> wt% of the cosolvent, preferably greater than zero to <NUM> wt%, based upon <NUM> wt% of the solvent mixture. The amount of cosolvent is determined based upon the desired degree of sulfonation. For example, for sulfonation of <NUM> to <NUM>%, the solvent mixture can comprise <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt%, poly(phenylene ether); <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt% <NUM>,<NUM>-dichloroethane; no cosolvent is necessary. However, for uniform sulfonation above <NUM>%, the presence of cosolvent is desirable. For example, for a uniform sulfonation level of <NUM>% to <NUM>%, the solvent mixture can comprise <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt%, poly(phenylene ether); <NUM> wt% to <NUM> wt%, preferably <NUM> wt% to <NUM> wt% <NUM>,<NUM>-dichloroethane, and <NUM> to <NUM> wt% preferably <NUM> to <NUM> wt%, cosolvent; based upon <NUM> wt% weight of the solvent mixture. The sulfonation level may be <NUM>% to <NUM>%, preferably <NUM>% to <NUM>%, as determined by NMR, or the sulfonated poly(phenylene ether) has a uniform sulfonation level in the range of <NUM> to <NUM>%, preferably in the range of <NUM>% to <NUM>%, more preferably <NUM>% to <NUM>%, as determined by NMR.

The solvent mixture can then be reacted with a sulfonating agent to sulfonate the poly(phenylene ether). The sulfonation can be performed at a temperature of up to <NUM>, e.g., <NUM> to <NUM>, or <NUM> to <NUM>. The amount of sulfonating agent added to the solvent mixture can be <NUM> to <NUM> mole, preferably <NUM> to <NUM> moles, based upon a total <NUM> mole of poly(phenylene ether) that was dissolved in the solvent mixture. The specific amount of sulfonating agent added is dependent upon the desired level of sulfonation in the sulfonated reaction product. Desirably, the sulfonating agent is added slowly to the solvent mixture, e.g., added over a period of <NUM> minutes (min. ) to <NUM>. , (e.g., over a period of <NUM> mins). Once the sulfonating agent is added to the solvent mixture, the solvent mixture can be stirred, e.g., for a period of time of <NUM> to <NUM> mins, prior to proceeding to precipitation.

Once the poly(phenylene ether) has been sulfonated, the sulfonated poly(phenylene ether) can be precipitated from the solvent mixture using an anti-solvent mixture, e.g., containing di-ionized (DI) water. For example, at least one of hexane, heptane, can be used, e.g., along with di-ionized water, to cause the sulfonated poly(phenylene ether) to precipitate out of the reaction solvent mixture. The reaction solvent mixture can be (e.g., slowly) added to the anti-solvent mixture, wherein the anti-solvent mixture can be used in an amount sufficient to induce precipitation. For example, <NUM> grams (g) solvent mixture can be added to <NUM> to <NUM>, preferably <NUM> to <NUM>, of the anti-solvent mixture with hexane to water weight ratios ranging from <NUM> to <NUM>.

The precipitated sulfonated poly(phenylene ether) can be filtered, and optionally washed and dried. The filtrate can be diphasic with the <NUM>,<NUM>-dichloroethane,cosolvent, and optionally organic(s) (e.g., hexane) that were part of the anti-solvent mixture, as the organic phase and water as the aqueous phase. The method may further comprise recovering the solvent and the cosolvent. Hence, the filtrate can be further processed to recover at least one of the <NUM>,<NUM>-dichloroethane, the cosolvent, or water; preferably to recover <NUM>,<NUM>-dichloroethane and the cosolvent, more preferably to recover <NUM>,<NUM>-dichloroethane, the cosolvent, and the water. Recovering the materials can comprise decanting the diphasic filtrate to form an aqueous stream and an organic stream. The organic stream can be further processed, e.g., distilled, to recover the <NUM>,<NUM>-dichloroethane and/or the cosolvent. The recovered materials can be recycled. Greater than <NUM> wt%, preferably greater than or equal to <NUM> wt% of the <NUM>,<NUM>-dichloroethane may be recycled, and/or greater than <NUM> wt%, preferably greater than or equal to <NUM> wt% of the cosolvent may be recycled; and/or greater than <NUM> wt%, preferably greater than or equal to <NUM> wt% of water used in the process may be recycled.

Referring now to <FIG> where the process is schematically illustrated. As is illustrated, the process entails introducing poly(phenylene ether), <NUM>,<NUM>-dichloroethane,to a mixing vessel <NUM>. The mixing vessel can be maintained at room temperature up to <NUM>, e.g., <NUM> to <NUM>, preferably <NUM> to <NUM>. Within the mixing vessel <NUM>, the poly(phenylene ether), <NUM>,<NUM>-dichloroethane, and a cosolvent, can be mixed, e.g., until homogenous, to form the solvent mixture. Optionally, the mixing can continue until a homogenous clear solution is obtained. From the mixing vessel <NUM>, the solvent mixture can be processed in a reaction vessel <NUM> along with a sulfonating agent. The sulfonated poly(phenylene ether) can then be precipitated from the mixture in a precipitation unit <NUM>, e.g., once the desired degree of sulfonation has been attained. For example, the reaction solvent mixture can be slowly added to the anti-solvent mixture (e.g., of hexane and DI water) to induce precipitation of the sulfonated poly(phenylene ether). The precipitated sulfonated poly(phenylene ether) can be separated from the liquid phase, e.g., in filtration unit <NUM>, before the sulfonated poly(phenylene ether) is optionally washed (such as with DI water), e.g., in wash units <NUM>,<NUM>, and dried, e.g., in drier <NUM>. Meanwhile, the liquid phase from the filtration unit <NUM> can be processed to remove water, e.g., in decantation unit <NUM> using liquid-liquid separation. The aqueous recovery phase from the decantation unit <NUM> can be processed in a multiple effect evaporator (MEE) <NUM> to recover the water. The resulting water can optionally be recycled, e.g., to, the wash unit <NUM>, or the precipitation unit <NUM>. The <NUM>, <NUM>-dichloroethane (EDC) stream from the decantation unit <NUM> can be further processed to separate the EDC by distillation in unit <NUM>. The separated EDC can optionally be recycled, e.g., to mixing vessel <NUM>.

Referring now to <FIG>, where the process is schematically illustrated. As is illustrated, the process entails introducing poly(phenylene ether), <NUM>,<NUM>-dichloroethane, and a cosolvent (ethyl acetate here), to a mixing vessel <NUM>. The mixing vessel can be maintained at room temperature up to <NUM>, e.g., <NUM> to <NUM>, preferably <NUM> to <NUM>. Within the mixing vessel <NUM>, the poly(phenylene ether), <NUM>,<NUM>-dichloroethane, and a cosolvent, can be mixed, e.g., until homogenous, to form the solvent mixture. Optionally, the mixing can continue until a homogenous clear solution is obtained. From the mixing vessel <NUM>, the solvent mixture can be processed in a reaction vessel <NUM> along with a sulfonating agent. The sulfonated poly(phenylene ether) can be precipitated from the mixture in a precipitation unit <NUM>, e.g., once the desired degree of sulfonation has been attained. For example, the reaction solvent mixture can be slowly added to the anti-solvent mixture (e.g., DI water) to induce precipitation of the sulfonated poly(phenylene ether). The precipitated sulfonated poly(phenylene ether) can be separated from the liquid phase, e.g., in filtration unit <NUM>, before the sulfonated poly(phenylene ether) is optionally be reslurried with a DI water- hexane mixture, e.g., followed by a wash (e.g., with DI water) in units <NUM>,<NUM>, and dried, e.g., in drier <NUM>. The wash from the wash units <NUM>,<NUM> can optionally be separated in decantation unit <NUM>, into an aqueous stream and a hexane stream. The hexane stream can optionally be recycled to the reslurry unit <NUM>. Meanwhile, the liquid phase from the filtration unit <NUM> can be processed to remove water, e.g., in decantation unit <NUM> using liquid-liquid separation. The aqueous phase from the decantation unit <NUM> and from decantation unit <NUM>, can be processed in the multiple effect evaporator <NUM> to recover the water. The resulting water can optionally be recycled, e.g., to the reslurry unit <NUM>, the wash unit <NUM>, or the precipitation unit <NUM>; and preferably to the reslurry unit <NUM>. The EDC stream from the decantation unit <NUM> can be further processed to separate the EDC, e.g., from organic(s) and/or residue by distillation in the unit <NUM>. The separated EDC can optionally be recycled, e.g., to mixing vessel <NUM>.

Referring now to <FIG>, where the process is schematically illustrated. As is illustrated, the process entails introducing poly(phenylene ether), <NUM>,<NUM>-dichloroethane, and a cosolvent (e.g., tetramethylene sulfone), to a mixing vessel <NUM>. The mixing vessel can be maintained at room temperature up to <NUM>, e.g., <NUM> to <NUM>, preferably <NUM> to <NUM>. Within the mixing vessel <NUM>, the poly(phenylene ether), <NUM>,<NUM>-dichloroethane, and cosolvent, can be mixed, e.g., until homogenous, to form the solvent mixture. Optionally, the mixing can continue until a homogenous clear solution is obtained. _From the mixing vessel <NUM>, the solvent mixture can be processed in a reaction vessel <NUM> along with a sulfonating agent. The sulfonated poly(phenylene ether) can be precipitated from the mixture in a precipitation unit <NUM>, e.g., once the desired degree of sulfonation has been attained. For example, the reaction solvent mixture can be slowly added to the DI water (used as the anti-solvent mixture) to induce precipitation of the sulfonated poly(phenylene ether). The precipitated sulfonated poly(phenylene ether) can be separated from the liquid phase, e.g., in filtration unit <NUM>, before the sulfonated poly(phenylene ether) is optionally reslurried in DI water- hexane mixture, e.g., followed by a wash (e.g., with DI water) in units <NUM>,<NUM>, and dried, e.g., in drier <NUM>. The wash from the wash units <NUM>,<NUM> can optionally be separated in decantation unit <NUM>, into an aqueous stream and hexane stream. The hexane stream can optionally be recycled to the reslurry unit <NUM>. Meanwhile, the liquid phase from the filtration unit <NUM> can be processed to remove water, e.g., in decantation unit <NUM> using liquid-liquid separation. The aqueous phase from the decantation unit <NUM> and from decantation unit <NUM>, can be processed in the multiple effect evaporator <NUM> to recover the water. The resulting water can optionally be recycled, e.g., to the reslurry unit <NUM>, the wash unit <NUM>, or the precipitation unit <NUM>; and preferably to the reslurry unit <NUM>. The EDC stream from the decantation unit <NUM> can be further processed to separate the EDC, e.g., from organic(s) and/or residue by distillation in the unit <NUM>. The separated EDC can optionally be recycled, e.g., to mixing vessel <NUM>.

A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> grams (g) of NORYL PPO™ <NUM> poly(phenylene ether) resin (commercially available from SABIC) was dissolved in <NUM> of <NUM>, <NUM>-dichloroethane (EDC) until a homogenous clear solution was obtained; <NUM> minutes (min. The temperature was subsequently reduced to <NUM>. <NUM> of chlorosulfonic acid was transferred to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane solution under vigorous stirring over a <NUM> minute period. A <NUM> rinse <NUM>,<NUM>-dichloroethane was used to flush the dropping funnel. A nitrogen purge was maintained although with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for ab additional <NUM> minutes at <NUM>. The reaction mass is subsequently slowly transferred along with hexane-deionized (DI) water ((<NUM> milliliters (ml):<NUM>) anti-solvent mixture) to a <NUM> liter (L) baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade agitator of about <NUM> millimeter (mm) diameter, running at <NUM>,<NUM> revolutions per minute (rpm), corresponding to <NUM> (in SI units), giving a tip-speed of <NUM> meters per second (m/s). The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM> hours. This was followed by filtration. The residue (sulfonated poly(phenylene ether) (sPPE)) was then reslurried in DI water and refiltered. The residue washed thoroughly with DI water until neutral pH. The sulfonated material was then dried under vacuum for <NUM> hours (h) at room temperature.

The industrial process scheme for the manufacture of sulfonated polyphenylene ether (sPPE) includes the dissolution of polyphenylene either (PPE) in <NUM>,<NUM>-dichloroethane (basis of <NUM> kilogram per hour (kg/hr) of poly(phenylene ether)) with a residence time of <NUM> to <NUM> minutes. Dissolved <NUM>,<NUM>-dichloroethane enters the reaction vessel where the reaction with chlorosulfonic acid (<NUM>/hr) takes place with the mole ratio of chlorosulfonic acid to poly(phenylene ether) of <NUM>. The reaction temperature is at <NUM> with the residence time of <NUM> mins. The hydrochloride (HCl) gas which is evolved during the process is vented from the reactor and scrubbed using an alkali scrubber. The reaction mass from the reactor is precipitated in a precipitation vessel with starting poly(phenylene ether) to anti-solvent mixture volume ratio of <NUM>:<NUM>.

The precipitated mass is filtered and the wet sPPE goes for the purification by passing through two wash vessels and dried in a drier at the temperature of <NUM> to <NUM> at reduced pressure of <NUM> millimeters of mercury (mmHg). The filtrate is biphasic with <NUM>,<NUM>-dichloroethane (EDC) and hexane being the organic phase and water as the aqueous phase. Decanting (liquid-liquid separation) is done to separate the EDC layer from the water followed by distillation to separate EDC from heavies. EDC formed heterogeneous azeotrope with water. The distillation operation separates EDC as a distillate (which can be recycled), and the organic heavies at the bottom. The recycle efficiency for water and solvent is more than <NUM>%. The entire scheme was simulated in Aspen to understand the recovery and recycle.

A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> of NORYL PPO™ <NUM> poly(phenylene ether) resin was dissolved in a <NUM>,<NUM>-dichloroethane and ethyl acetate (EA) (<NUM>:<NUM>) mixture until a homogenous clear solution was obtained; <NUM>. The temperature was maintained at <NUM>. <NUM> of chlorosulfonic acid was transferred to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane-ethylacetate solution mixture under vigorous stirring over a <NUM> minute period. A nitrogen purge was maintained through with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for an additional <NUM> minutes at <NUM>. The reaction mass was subsequently slowly transferred along with <NUM>,<NUM> of DI water (e.g., as the anti-solvent mixture) to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade agitator of about <NUM> diameter, running at <NUM>,<NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM> mins. This was followed by filtration. The residue (sulfonated PPO) was then reslurried in DI water- hexane (<NUM>:<NUM>) mixture and refiltered. The residue was washed thoroughly with DI water until neutral pH. The sulfonated material is then dried under vacuum for <NUM> hours at room temperature.

The industrial process scheme for the manufacture of sulfonated PPO (sPPE) includes dissolution of poly(phenylene ether) in <NUM>,<NUM>-eichloroethane and ethyl acetate (basis of <NUM>/hr of poly(phenylene ether)) in the amount of <NUM> wt% EDC, <NUM> wt% poly(phenylene ether) and <NUM> wt% EA, based upon a total weight of the poly(phenylene ether), EA, and EDC, with a residence time of <NUM> to <NUM> minutes. Dissolved poly(phenylene ether) goes to the reaction vessel where the reaction with chlorosulfonic acid (<NUM>/hr) takes place with the mole ratio of chlorosulfonic acid to poly(phenylene ether) of <NUM>. The reaction temperature is at <NUM> with the residence time of <NUM> mins. The HCl gas which is evolved during the process is vented from the reactor and scrubbed using alkali scrubber. The reaction mass from the reactor is precipitated in a precipitation vessel with starting poly(phenylene ether):water volume ratio of <NUM>:<NUM>.

The precipitated mass is filtered and the wet sPPE goes for the purification by passing through two wash vessels and dried in a drier at the temperature of <NUM> to <NUM> at reduced pressure of <NUM> millimeters of mercury (mmHg). The filtrate is biphasic with <NUM>,<NUM>-dichloroethane and EA being the organic phase and water as an aqueous phase. Decanting (liquid-liquid separation) is done to separate the EDC and EA from water followed by distillation to separate EDC and EA. Both EDC and EA forms heterogeneous azeotrope with water. The distillation operation separates EDC and EA as a distillate which can be recycled and the organic heavies at the bottom. The recycle efficiency for water and solvent is more than <NUM>%. The entire scheme was simulated in Aspen to understand the recovery and recycle.

A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> of NORYL PPO™ <NUM> poly(phenylene ether) resin was dissolved in a <NUM>,<NUM>-dichloroethane and ethyl acetate (<NUM>:<NUM>) mixture until a homogenous clear solution was obtained; <NUM>. The temperature was maintained at <NUM>. Chlorosulfonic acid (<NUM>) was transferred accurately to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane and ethyl acetate mixture under vigorous stirring over a <NUM>-min period. A nitrogen purge was maintained although with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for an additional <NUM> minutes at <NUM>. The reaction mass is subsequently slowly transferred along with <NUM> of DI water (used as the anti-solvent mixture) to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade of agitator of approximately <NUM> diameter, running at <NUM>,<NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM>. This was followed by filtration. The residue (sPPE) is then reslurried in DI water/hexane (<NUM>:<NUM>) mixture and refiltered. The residue washed thoroughly with DI water until neutral pH. The sulfonated poly(phenylene ether) is then dried under vacuum for <NUM> hours at room temperature.

The industrial process scheme for the manufacture of sulfonated poly(phenylene ether) includes the dissolution of poly(phenylene ether) in <NUM>,<NUM>-dichloroethane and ethyl acetate (basis -<NUM>/hr of poly(phenylene ether)) in the amount of <NUM> wt% EDC, <NUM> wt% poly(phenylene ether) and <NUM> wt% EA with a residence time of <NUM> to <NUM> minutes. Dissolved poly(phenylene ether) is introduced to the reaction vessel where the reaction with chlorosulfonic acid (<NUM>/hr) takes place with the mole ratio of <NUM> with respect to poly(phenylene ether). The reaction temperature is at <NUM> and the residence time is <NUM>. The HCl gas, which is evolved during the process, is vented from the reactor and scrubbed using an alkali scrubber. The reaction mass from the reactor is precipitated in a precipitation vessel with poly(phenylene ether):water volume ratio of <NUM>:<NUM>.

The precipitated mass is filtered and the wet sPPE is purified by passing through two wash vessels and is dried in a drier at the temperature of <NUM> to <NUM> at reduced pressure of <NUM> mmHg. The filtrate is biphasic with <NUM>,<NUM>-dichloroethane and EA being the organic phase and water as the aqueous phase. Decanting (liquid-liquid separation) is done to separate the EDC and EA from the water followed by distillation to separate the EDC and the EA. Both EDC and EA form heterogeneous azeotropes with water. The distillation operation separates the EDC and the EA as a distillate that can be recycled with organic heavies at the bottom. The recycle efficiency for water and solvent is more than <NUM>%. The entire scheme was simulated in Aspen to understand the recovery and recycle.

Additional reactions were performed to determine a desired sulfonation reaction time after the addition of chlorosulfonic acid in Example <NUM>. The scheme is illustrated in <FIG>.

A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> of NORYL PPO™ <NUM> poly(phenylene ether) resin was dissolved in a <NUM>,<NUM>-dichloroethane and ethyl acetate (<NUM>:<NUM>) mixture until a homogenous clear solution was obtained; <NUM>. The temperature was maintained at <NUM>. Chlorosulfonic acid (<NUM>) was transferred accurately to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane and ethyl acetate mixture under vigorous stirring over a <NUM>-min period. A nitrogen purge was maintained although with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for an additional <NUM> minutes at <NUM>. The reaction mass is subsequently slowly transferred along with <NUM> of DI water (used as the anti-solvent mixture) to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade of agitator of approximately <NUM> diameter, running at <NUM>,<NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM>. This was followed by filtration. The residue (sPPE) is then reslurried in DI water/hexane (<NUM>:<NUM>) mixture and refiltered. The residue washed thoroughly with DI water until neutral pH. The sulfonated material is then dried under vacuum for <NUM> hours at room temperature.

The corresponding data as given in the table for products properties below, show that the target ion exchange capacity (IEC) can be achieved within <NUM> hours after the addition of chlorosulfonic acid.

A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser, and a pressure equalized dropping funnel, was maintained at <NUM>. <NUM> of NORYI, PPO™ <NUM> poly(phenylene ether) resin was dissolved in a <NUM>,<NUM>-dichloroethane and ethyl acetate (<NUM>: <NUM>) mixture until a homogenous clear solution was obtained; <NUM>. The temperature was maintained at <NUM>. Chlorosulfonic acid (<NUM>) was transferred to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane and ethylacetate mixture under vigorous stirring over a <NUM> minute period. A nitrogen purge was maintained through with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for an additional <NUM> minutes at <NUM>. The reaction mass is subsequently slowly transferred along with <NUM>,<NUM> of DI water to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade of agitator of approximately <NUM> diameter, running at <NUM>,<NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM>. This was followed by filtration. The residue (sPPE) was then reslurried in a DI water and hexane (<NUM>: <NUM>) mixture and refiltered. The residue washed thoroughly with DI water until neutral pH and then dried under vacuum for <NUM> hours at room temperature.

The industrial process scheme for the manufacturing of sPPE includes the dissolution of poly(phenylene ether) in <NUM>,<NUM>-dichloroethane and ethyl acetate (basis -<NUM>/hr of poly(phenylene ether)) in the amount of <NUM> wt% EDC, <NUM> wt% poly(phenylene ether) and <NUM> wt% EA, based upon a total weight of the poly(phenylene ether), EA, and EDC, with a residence time of <NUM> to <NUM> minutes. Dissolved poly(phenylene ether) goes to the reaction vessel where the reaction with chlorosulfonic acid (<NUM>/hr) takes place with the mole ratio <NUM> with respect to PPO. The reaction temperature is at <NUM> with the residence time of <NUM> mins. The HCl gas which is evolved during the process is vented from the reactor and scrubbed using alkali scrubber. The reaction mass from the reactor is precipitated in a precipitation vessel with poly(phenylene ether): water volume ratio of <NUM>:<NUM>.

The precipitated mass is filtered and the wet SPPE goes for the purification by passing through two wash vessels and dried in a drier at the temperature of <NUM> to <NUM> at reduced pressure of <NUM> mmHg. The filtrate is a biphasic with <NUM>,<NUM>-Dichloroethane and EA are the organic phase and water as an aqueous phase. Decanting (liquid-liquid separation) is done to separate the EDC & EA from water followed by distillation to separate EDC and EA. Both EDC and EA forms heterogeneous azeotrope with water. The distillation operation separates EDC and EA as a distillate which can be recycled and the organic heavies at the bottom. The recycle efficiency for water and solvent is more than <NUM>%. The entire scheme has been simulated in Aspen to understand the recovery and recycle.

A <NUM>-necked round bottom glass flask equipped with a Teflon stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> of NORYL PPO™ <NUM> poly(phenylene ether) resin was dissolved in <NUM>,<NUM>-Dichloroethane and tetramethylene sulfone (<NUM>: <NUM>) solvent mixture till a homogenous clear solution was obtained in <NUM> mins. The temperature was maintained at <NUM>. <NUM> gm of chlorosulfonic acid was transferred accurately to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-Dichloroethane- tetramethylene sulfone solution mixture under vigorous stirring over a <NUM>-minute period. A nitrogen purge was maintained although with rapid stirring. At the end of this addition, the stirred solution becomes slightly cloudy. Stirring was continued for additional <NUM> minutes at <NUM>. The reaction mass is subsequently slowly transferred with <NUM> of DI water-hexane (<NUM>:<NUM> w/w) (used as the anti-solvent mixture) to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade of agitator of ~<NUM> diameter, running at <NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM> mins. This was followed by filtration. The residue (sulfonated poly(phenylene ether)) was then reslurried in <NUM> DI water and refiltered. The residue washed thoroughly with DI water until neutral pH. The sulfonated material was then dried under vacuum for <NUM> hours at room temperature.

The Industrial process scheme for the manufacturing of the sulfonated poly(phenylene ether) consist of dissolution of poly(phenylene ether) in <NUM>,<NUM>-dichloroethane and tetramethylene sulfone (basis -<NUM>/hr of poly(phenylene ether)) in an amount of <NUM> wt% EDC, <NUM> wt% poly(phenylene ether) and <NUM> wt% tetramethylene sulfone, based upon a total weight of the poly(phenylene ether), tetramethylene sulfone, and EDC, with a residence time of <NUM> to <NUM> minutes. Dissolved poly(phenylene ether) goes to the reaction vessel where the reaction with chlorosulfonic acid (<NUM>/hr) takes place with the mole ratio of <NUM> with respect to the poly(phenylene ether). The reaction temperature is at <NUM> with the residence time of <NUM>. The HCl gas, which is evolved during the process, is vented from the reactor and scrubbed using alkali scrubber. The reaction mass from the reactor is precipitated in a precipitation vessel with starting poly(phenylene ether): anti-solvent mixture volume ratio of <NUM>:<NUM>.

The precipitated mass is filtered and the wet sPPE goes for purification by passing through two wash vessels and dried in a drier at the temperature of <NUM> to <NUM> at reduced pressure of <NUM> mmHg. The filtrate is biphasic with <NUM>,<NUM>-dichloroethane, and tetramethylene sulfone are the organic phase and water as the aqueous phase. Decanting (liquid-liquid separation) to separate the EDC and tetramethylene sulfone from the water followed by distillation to separate the EDC and the tetramethylene sulfone. The distillation operation separates the EDC and the tetramethylene sulfone, as a distillate which can be recycled, with the organic heavies at the bottom. The recycle efficiency for the water and the solvent is more than <NUM>%. The entire scheme has been simulated in Aspen to understand the recovery and recycle.

A multi neck <NUM> reactor equipped with overhead stirrer reflux condenser, addition port and nitrogen purger was charged with NORYI, PPO™ <NUM> poly(phenylene ether) resin (at a reaction temperature (RT) of <NUM> to <NUM>) and <NUM>,<NUM> ethylene dichloride (EDC). The reaction mass (RM) was heated to <NUM> to <NUM> under stirring to get clear solution. Chlorosulfonic acid was added under nitrogen purging over a period of <NUM> to <NUM> under vigorous stirring. The resultant reaction mass was stirred vigorously at RT for another <NUM> under nitrogen. The reaction mass was added to a <NUM> reactor containing pre-cooled mixture of <NUM> hexane and <NUM> DI water. The resultant precipitate was allowed to reach RT and was stirred at that same temperature for <NUM> hours. The solids were filtered via centrifuge and spin dried, and the wet solids were unloaded. The wet solids were stirred with <NUM> DI water at RT for <NUM>. The solids were filtered via centrifuge; spin dried well and the wet solids were unloaded. The wet solids were reslurried with additional <NUM> DI water at RT for <NUM> hours at a neutral pH to isolate the sulfonated product.

The solids were dried in a vacuum tray drier (VTD) at temperature of <NUM> to <NUM> for <NUM>. The resultant sulfonated polymer weighed: ~ <NUM>.

Example <NUM> was repeated without the use of a cosolvent. A <NUM>-necked round bottom glass flask equipped with a TEFLON stirrer, a reflux condenser and a pressure equalized dropping funnel was maintained at <NUM>. <NUM> of NORYI, PPO™ <NUM> poly(phenylene ether) resin was dissolved in a <NUM>,<NUM>-dichloroethane (<NUM>) mixture until a homogenous clear solution was obtained; <NUM>. The temperature was maintained at <NUM>. <NUM> of chlorosulfonic acid was transferred to a pressure equalized dropping funnel and the same was added into the <NUM>,<NUM>-dichloroethane solution mixture under vigorous stirring over a <NUM> minute period. A nitrogen purge was maintained through with rapid stirring. At the end of this addition, the reaction mass developed heterogeneity and the product precipitated out of the reaction mass. Stirring was continued for an additional <NUM> minutes at <NUM>. The reaction mass was subsequently slowly transferred along with <NUM>,<NUM> of DI water (e.g., as the anti-solvent mixture) to a <NUM> baffled precipitation vessel maintained at <NUM> and fitted with a <NUM>-blade agitator of about <NUM> diameter, running at <NUM>,<NUM> rpm, corresponding to <NUM> (in SI units), giving a tip-speed of <NUM>/s. The temperature was subsequently ramped up to <NUM> after <NUM> hour. The stirring was continued for a total of <NUM> mins. This was followed by filtration. The residue (sulfonated PPO) was then reslurried in DI water- hexane (<NUM>:<NUM>) mixture and refiltered. The residue was washed thoroughly with DI water until neutral pH. The sulfonated material is then dried under vacuum for <NUM> hours at room temperature.

The sulfonated product once isolated using the exact procedure as cited in Example <NUM>, had a degree of sulfonation of was <NUM> to <NUM>% (non-uniform) as measured by NMR. This level was lower than the <NUM>% degree of sulfonation of Example <NUM> which used ethyl acetate as a cosolvent. The development of heterogeneity and the subsequent phase separation of the sulfonated polymer prevented further sulfonation beyond <NUM>%. However, as illustrated in Examples <NUM> through <NUM>, inclusions of the co-solvent, ensured reaction homogeneity through the course of the sulfonations enabling higher degrees of sulfonation in the product, e.g., <NUM>% here, with <NUM>% in Example <NUM>.

Ion Exchange Capacity by potentiometry: The ion exchange capacity (IEC) indicates the number of milliequivalents of ions in <NUM> of the dry polymer. The degree of substitution (DS) indicates the percentage of repeat units bearing the sulfonic acid group along the sulfonated polymer molecular chain. The method involves dissolving the sPPE in a dimethyl acetamide/isopropyl alcohol mixture and titrating with alcoholic potassium hydroxide by potentiometric method. This non-aqueous titration was performed with Solvatrode (commercially available from Metrohm USA) as the electrode. This method uses a two solvent system. Consequently a sharp and reproducible end point is obtained.

The sample was dissolved in the dimethyl acetamide and was diluted with the isopropyl alcohol to get reproducible ion exchange capacity. With only dimethyl acetamide, no sharp end point was obtained with considerable variability in replicate analysis. Not to be limited by theory, it is believed that this bi-solvent system helps in controlling the polarity and enables attaining a reproducible, sharp end point. <MAT> Where:.

Degree of sulfonation (DS) (also referred to as sulfonation level) determined by nuclear magnetic resonance spectroscopy (NMR): The samples are dissolved in dimethyl sulfoxide-d<NUM> (DMSO-d<NUM>, also known as deuterated DMSO) (with the help of overnight shaking in a horizontal shaker), <NUM> scans were averaged with <NUM> seconds delay. In case of undissolved portions, the solvent vial was sonicated in a water bath at <NUM> for <NUM>-<NUM> minutes. An example of the resulting graph is illustrated in <FIG>.

The degree of sulfonation can be calculated either from the aliphatic or aromatic protons:.

wherein I is Integration value of the NMR chemical shifts at a given ppm. Refer NMR Spectra in the disclosure.

Molecular Weight: A gel permeation chromatography (GPC) method for estimation of the molecular weight (weight average molecular weight (Mw) and number average molecular weight (Mn)) was developed for the sPPE by using dimethyl formamide as a mobile phase with <NUM> wt%, based upon the weight of the mobile phase of lithium bromide as an additive. Agilent <NUM> x (e.g., <NUM> columns) PLgel <NUM> micrometer (µm) MIXED-B, <NUM> x <NUM>, with one guard, column was used for the elution of sPPE with <NUM> milliliter per minute (ml/min) flow rate and <NUM> of column temperature. Ultraviolet (UV) detector (at <NUM> nanometers (nm)) was used to record the GPC chromatogram of sPPE, with an elution time of <NUM>. Samples were slowly dissolved in the dimethyl formamide solvent at a concentration of two milligram per milliliter (mg/ml) for about <NUM> to <NUM> hours in a horizontal shaker. The solutions were filtered through a <NUM> PTFE filter into a GPC auto sampler vials for analysis. The GPC system calibrated with polystyrene standards in the range of to <NUM> Dalton (Da) to <NUM> kDa (i.e. in the range of to <NUM> to <NUM>· <NUM><NUM> atomic mass units in SI units). Agilent ChemStation software was used to set the baseline points.

Polydispersity Index (PDI or Ð): can be determined by the following formula: <MAT>.

Estimation of solubility: <NUM> of the sPPE was placed in <NUM> of the respective solvents in polypropylene centrifuge tubes. The solvents were tetrahydrofuran (THF), methanol (MeOH), N-methyl-<NUM>-pyrroilidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc). The same were kept in shaker for <NUM> hours. The solutions were subsequently observed for any inhomogeneity.

The recovery and recycling of the solvent and co-solvent has been studied by simulation and demonstrated in the lab scale for understanding the commercial viability of the process involving recovery and recycling of the solvent streams. The solvent quantity and type has been selected considering the recyclability of solvent as one of the principles in the claimed scheme.

In this process the major solvent which is common in all the examples is <NUM>, <NUM> dichloroethane which is distilled in the distillation unit (<NUM>) from the trace of water and recycled. In all the cases the recovery is above <NUM>% in terms of the <NUM>, <NUM> dichloroethane.

The ethyl acetate is used as a co-solvent along with the <NUM>, <NUM> dichloroethane in Examples <NUM>, <NUM>-<NUM>, and <NUM>. The ethyl-acetate together with the <NUM>, <NUM> dichloroethane can be distilled in the distillation unit (<NUM>) and recycled for the sulphonation reaction. The recovery of the ethyl-acetate is above <NUM>%.

The recycle of water is common in all of the above examples, after the separation of aqueous vs organic in the decanter (<NUM>) the aqueous layer (mainly water) is evaporated in a multiple effect evaporator and recycled e.g., to precipitation and/or filtration units. The recycled water accounts to be <NUM>%, preferably <NUM>% or more, of the total quantity of water used.

Hence, the commercial viability of this sulfonation process wherein poly(phenylene either is sulfonated to <NUM>%-<NUM>% using <NUM>, <NUM> dichloroethane and a co-solvent. Has been proven. Although the ethyl-acetate has greater recyclability, the cosolvent can be at least one of methyl ethyl ketone, diethyl ether, methyl ethyl sulfone, ethyl acetate, or tetramethylene sulfone.

As used herein "uniform" means the same degree of sulfonation across the isolated mass of the sulfonated polymer product as determined by <NUM>-NMR of at least <NUM> small samples taken from the entire product mass.

All weight percentages are based upon a total of <NUM> weight percent.

Claim 1:
A method for sulfonation of poly(phenylene ether), comprising
dissolving a poly(phenylene ether) comprising <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>,<NUM>-trimethyl-<NUM>,<NUM>-phenylene ether units, <NUM>,<NUM>',<NUM>,<NUM>'-tetramethyl-<NUM>,<NUM>'-dihydroxybiphenyl ether units, or a combination thereof, in a mixture of <NUM>,<NUM>-dichloroethane and preferably a cosolvent to form a solvent mixture in a mixing vessel;
combining a sulfonating agent with the solvent mixture, wherein the sulfonating agent reacts with the poly(phenylene ether) to form sulfonated poly(phenylene ether);
precipitating the sulfonated poly(phenylene ether); and
filtering the precipitated sulfonated poly(phenylene ether) to form a sulfonated poly(phenylene ether) precipitate and a filtrate;
wherein the sulfonated poly(phenylene ether) has a sulfonation level of <NUM> to <NUM>%.