FIELD OF THE INVENTION

[0001] The present disclosure relates to polymer sorbent materials and methods of preparing polymer sorbent materials particularly those useful in the sorption of nitrogen- containing compounds.

BACKGROUND OF THE INVENTION

[0002] The process of extraction of contaminants or undesired materials is applicable throughout a number of fields. Methods have been employed to remove nitrogen-containing compounds from their aqueous and organic solvents for purification and environmental treatment purposes.

SUMMARY OF THE INVENTION

[0003] Sorbent materials, such as polymer sorbent materials, have found a broad use of applications in the extraction of materials, particularly throughout the medical field. In kidney dialysis, sorbent materials have been used to extract or separate toxins from dialysate solutions in sorbent-based dialysis treatment. There remains a need for efficient and effective sorbent systems, particularly sorbent polymer systems, which limit the amount of waste water used in dialysis as well as reduce the toxicity of the diasylate solution while improving also sorption capacity of existing sorbent dialysis systems. These needs and other needs are satisfied by the various aspects of the present disclosure.

[0004] The present disclosure relates to methods of making polymer sorbents derived from polyvinyl polymers. In various aspects, the disclosure relates to sorbent polymer

compositions configured for the extraction of nitrogen-containing compounds from aqueous and/or organic solvents.

[0005] Methods of making polymer sorbents may comprise: a) reacting a polyvinyl polymer under first reaction conditions effective to provide a first reaction product comprising at least one glyoxal group wherein the glyoxal content is up to 3 millimole per gram (mmol/g) as compared to 1 mmol/g for existing resins. In some aspects, the method for making polymer sorbents comprises a) reacting a polyvinyl polymer under first reaction conditions effective to provide a first reaction product; b) reacting the first reaction product under second reaction conditions effective to provide a second reaction product; and c) reacting the second reaction product to provide a third reaction product comprising at least one glyoxal group with a loading of up to about 3 millimole per gram (mmol/g). [0006] In one aspect, the disclosure relates to a method for preparing a polymer sorbent comprising a) reacting polyvinyl polymer under first reaction conditions effective to provide a first reaction product comprising at least one halogen; and b) reacting the first reaction product to provide a second reaction product comprising at least one glyoxal group with a loading of up to about 3 mmol/g.

[0007] In further aspects, the disclosure relates to a polymeric phenylglyoxal resin comprising at least one glyoxal group with a loading of up to about 3 mmol/g, the polymeric phenylglyoxal resin produced by a process comprising reacting a polyvinyl polymer.

[0008] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0009] Additional aspects of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the disclosure. The advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.

DETAILED DESCRIPTION OF THE INVENTION

[0010] The methods of the present disclosure relate to the preparation of a polymer sorbent, particularly, the preparation of a polymer sorbent for separating materials from a fluid. These polymer sorbents may provide a mechanism for the extraction of materials from a given liquid. When in contact with a fluid, the polymer sorbents may be used to extract materials therefrom. [0011] Providing the nature of the polymer sorbent, certain materials may be removed from a fluid when placed in contact with the sorbent. The polymer sorbent of the present disclosure may be used to remove nitrogen-containing materials. For example, the materials may comprise amines, amides, amidines, guanidines, thiouresas, ammonia, urea, creatinine, or uremic toxins, or combinations thereof.

[0012] In various aspects, the polymer sorbents prepared herein may thus be useful for performing separation in a number of fluid systems. These fluid systems may include, but are not limited to, water, waste water, organic solvents, blood, blood serums, and dialysis fluid. More specifically, the disclosed polymer sorbents may be used to separate, or extract, materials from their aqueous and organic environments for purification or treatment purposes.

[0013] In a specific example, the polymer sorbents may be useful in hemodialysis, or dialysis, for the treatment of dialysis fluids such as dialysate. The medical process of dialysis features the removal of toxins and other solutes from blood. These toxins and solutes include nitrogen containing compounds, such as urea. During dialysis, the toxins and solutes are generally removed from blood via a semi-permeable filtering membrane which is housed in a dialyzer. Generally, the blood for treatment and an aqueous solution (referred to as a diasyslate) are pumped in alternating directions about the semi-permeable membrane within the dialyzer. Toxins accumulated within the flowing blood are extracted according to a combination of diffusion, convection, and osmosis process as the blood flows within the semi-permeable membrane and the dialysate flows outside of the membrane. Conventional dialyzers may be characterized as single pass or sorbent-based. A single pass dialyzer requires a continuous supply of clean water to facilitate toxin removal, amounting to significant amounts of water. Sorbent-based dialyzers require that the dialysate is detoxified, or regenerated, by introducing the dialysate to chemical compounds to extract toxins, or undesired solutes. In conventional sorbent-based dialyzers, discretely configured chemical layers are employed to remove toxins and compounds from the diasylate. The discrete chemical layers of the dialysate detoxification process however may be accompanied with unfavorable safety concerns including the toxicity of certain ion exchanger technologies. Modern sorbent materials have been developed to avoid the disadvantages of ionic waste in the enzymatic layered process, but may require substantial synthetic steps to achieve the desired polymer. In some aspects, the methods of the present disclosure provide polymer sorbents for selective removal of materials, or the undesired toxins, from a dialysate. Further, the polymer sorbents have improved sorption capacity and are prepared via fewer, and less intensive, synthetic steps. When in contact with a fluid, such as the dialysate, the polymer sorbents disclosed herein may bind any present nitrogen-containing materials, including amines, amides, amidines, guanidines, thioureas, and ureas.

[0014] The polymer sorbent may be in contact with the fluid to be treated in a number of ways. For example, the polymer sorbent may be dispersed in the fluid comprising the material to be extracted. Meanwhile, the fluid may be agitated by some means, such as stirring, for the period of time necessary for removal of the material from the fluid. In a further example, the fluid may also be directed through a vessel, such as column, containing the polymer sorbent. As the fluid passes through the column, the fluid interacts with the polymer sorbent to facilitate binding of the material and, ultimately, its extraction. The polymer sorbent may assume any number of forms to be in contact with a particular fluid. The polymer sorbent may comprise a membrane through which the fluid, such as a dialysate, may pass. In further examples, the polymer sorbent may comprise a collection of fibers, a collection of hollow fibers, flat membranes or films, beads, powders, or a combination thereof through which a fluid, such as the dialysate, may flow. In still further examples, the polymer sorbent may comprise a solution or gel in organic, aqueous or mixed aqueous- organic solvent. The polymer sorbent may remove contaminants from a fluid, such as dialysate, by inclusion of contaminants in gel or a contaminant-polymer co-precipitation from a solution.

[0015] In various further aspects, the polymer sorbent may have certain surface characteristics that facilitate overall contact with the fluid. As an example, the polymer sorbent may be configured as porous resin beads. In various aspects, the porosity and surface are of the polymer solvent may be characteristics of any solid (or insoluble) form of the polymer solvent. Still, porosity and surface area may be characteristics most applicable to powders and beads. The polymer sorbent may exhibit a mean pore size of from about 14 Angstroms (A) to 1000 A. As a further example, the polymer sorbent may exhibit a pore volume of from about 0.3 milliliters per gram (mL/g) to about 1.85 mL/g. The polymer sorbent may also have a particular surface area for the extraction of nitrogen containing materials from a fluid, quantitatively characterized by nitrogen surface area (NSA). In one example, the polymer sorbent may have a nitrogen surface area of from about 150 square meters per gram (m ² /g) to about 1 100 m ² /g.

[0016] In some aspects of the present disclosure, the polymer sorbent comprises a functionalized styrenic (co)polymer. The functionalized styrenic (co)polymer may include at least one glyoxal group with a loading of up to about 3 millimole per gram (mmol/g). For example, the polymer sorbent may comprise a polymeric phenylglyoxal resin. The phenylglyoxal resin may include repeating glyoxal or gly oxalic acid units. In certain aspects, the glyoxal or gly oxalic acid units may be disposed at the meta positions of the styrenic polymer chain or at the para positions of the styrenic polymer chain, or at a combination thereof.

[0017] In further aspects, the polymer sorbent may have a surface modified to include one or more functional groups. These functional groups may bind nitrogen containing materials through inter- or intramolecular hydrogen, covalent bonds or their combination. According to the methods disclosed herein, the polymer sorbent comprising a styrenic (co)polymer resin may be modified to include certain functional groups. For example, the functional groups may include, but are not limited to carboxylates, aldehydes, keto-aldehydes, keto- carboxylates, hydroxyls, and hydroxy -ketones.

A. POLYVINYL POLYMER

[0018] In accordance with the purpose(s) of the disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to polymer sorbents useful in selectively binding nitrogen containing materials, from organic and aqueous solution. In various aspects, the polymer sorbent described herein may be derived from a polyvinyl polymer. More specifically, the present disclosure relates to methods of preparing a polymer sorbent from a styrenic(co)polymer. As an example, the styrenic (co)polymer comprises a divinyl benzene (DVB) (co)polymer having a structure represented by one of the formulas:

wherein R is each independently selected from, for example, hydrogen, C 1-C3 alkyl, aryl (phenyl, substituted phenyl, naphthyl), substituted alkyl (hydroxyalkyl), formyl, carbonyl, carboxyl, carboxylate, substituted carboxylate (i.e. hydroxyalkyl carboxylate), amide, substituted amide (N-alkyl, N-hydroxy alkyl), hydroxyl and its derivatives (i.e., acetoxy). In some examples, the divinyl benzene (co)polymer has a divinyl benzene content between 50 wt. % and 100 wt. %. B. METHODS OF MAKING THE COMPOUNDS AND COMPOSITIONS

[0019] In one aspect, the disclosure relates to methods of making a polymer sorbent material useful in extracting nitrogen containing compounds from aqueous and organic solutions. In various aspects, the polymer sorbent material comprises a loading of up to about 3 mmol/g of glyoxal groups.

[0020] In one aspect, the disclosed polymer sorbents comprise the reaction products of the synthetic methods described herein. In a further aspect, the disclosed polymer sorbents comprise a compound produced by a synthetic method described herein. In a still further aspect, the disclosure comprises a polymeric composition comprising the reaction product of the disclosed methods.

[0021] In a further aspect, the polymer sorbents according to the disclosure can generally be prepared by a succession of reaction steps. In a still further aspect, the polymer sorbents can be prepared according to the following synthesis methods.

[0022] As briefly described, the methods comprise at least one reaction or reacting step. In further aspects, reacting or the reaction step comprises any reaction condition effective to produce a desired reaction product or result, for example, reacting a reactant under reaction conditions effective to provide a reaction product comprising at least one desired compound. In still further aspects, the method can comprise any number of reaction conditions, for example, a first, second, third, fourth, and fifth reaction condition, or any combination thereof. In yet further aspects, each reacting step or reaction can comprise any number of reaction conditions, for example, a first, second, third, fourth, and fifth reaction condition, or any combination thereof. In further aspects, the method can provide any number of reaction products, for example, a first, second, third, fourth, and fifth reaction product, or any combination thereof. In still further aspects, each reacting step or reaction can provide any number of reaction products, for example, a first, second, third, fourth, and fifth reaction product, or any combination thereof.

[0023] In further aspects, conditions effective comprise adjusting the temperature between about 0 degrees Celsius (°C) to at least about 50 °C In still further aspects, the temperature is adjusted to a temperature of from 50 °C to about 250 °C, including exemplary

temperatures of about 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 1 15, 120, 125, 130, 135, 140, 145, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, and 245 °C [0024] In further aspects, conditions effective comprise maintaining the reaction for at least about 1 hour. In still further aspects, the reaction is maintained for about 1 to about 20 hours, including exemplary times of 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1, 12, 13, 14, 15, 16, 17, 18, and 19 hours.

[0025] In further aspects, conditions effective comprise adjusting the pH to a range of from 1 to about 14, including exemplary values of 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1, 12, and 13.

[0026] In various aspects, the reaction conditions comprise one or more of an epoxidation, bromination, or oxidation, or a combination thereof to achieve the polymer sorbent disclosed herein. An as example, the preparation of the polymer sorbent may comprise one or more of a first reaction conditions, a second reaction conditions, or a third reaction conditions wherein any of the reaction conditions may include one or more of epoxidation, bromination, or oxidation.

[0027] In one aspect, the reaction conditions may comprise epoxidation. An exemplary epoxidation condition includes oxirane formation. For epoxidation, or to form an oxirane, the reaction conditions may comprise reacting a reactant, such as the polyvinyl polymer, with an oxidizer, or an oxidizing agent, in the organic or aqueous-organic media compatible with the polymer. Exemplary oxidizers comprise but are not limited to hydrogen peroxide, tert-butyl peroxide, perbenzoic acid, substituted perbenzoic acid, peracetic acid, oxone, iodosylbenzene, or diacyl iodosobenzene, and any combinations thereof. In one example, reaction conditions may comprise reacting a styrenic (co)polymer resin with hydrogen peroxide in acetic anhydride under first reaction conditions to provide a first reaction product comprising at least one epoxy group.

[0028] In a further aspect, reaction conditions may comprise an epoxy -ring opening.

Epoxy (or oxirane) ring opening may be performed in organic solvent compatible with polymer and that can be mixed, or partially mixed, with water in the presence of a basic, acidic, or salt catalyst. Suitable organic solvents may include, but are not limited to methanol, ethanol, C3-C 10 alcohols, acetonitrile, acetone, methylethyl ketone, acetic acid, C3-C5 carboxylic acids, dichloroethane, toluene, Ν,Ν-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or their mixtures. Exemplary ring opening acidic catalysts may comprise, but are not limited to, protic acid, i.e., hydrochloric acid, sulfuric acid, perchloric acid, benzoic acid, substituted benzoic acid, benzene sulfonic acid, substituted benzene sulfonic acid, or Lewis acid, i.e. ferrous chloride, aluminum chloride, zinc chloride, or any combination thereof. Oxirane ring opening basic catalyst may comprise, but are not limited to, sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium carbonate, organic linear or cyclic tertiary amines, i.e. trialkylamines, N-alkyl morpholine, N-alkylpiperidine, pyridine and any combination thereof. Exemplary oxirane ring opening salt catalyst may comprise, but are not limited to, inorganic, i.e. sodium nitrite, and linear and cyclic tetraalkyl ammonium salts. In one example, reaction conditions may comprise reacting a styrenic (co)polymer resin having epoxy groups with sulfuric acid in glacial acetic acid in an amount of 5-10 % by volume of water.

[0029] In some aspects, the reaction conditions may comprise halogenation, or the addition of one or more halogen groups. More specifically, the reaction conditions may comprise the addition of one or more halogen groups to one or more vinylic groups of the styrenic (co)polymer resin. The addition of one or more halogen groups may be achieved by reacting a reagent or a reaction product in the presence of a halogen source. Exemplary halogen sources may include, but are not limited to, hydrogen bromide, di-molecular bromine Br ₂ and iodine h, N-bromosuccinimide (NBS), and potassium bromide/potassium persulfate salts. The halogen sources may be used in 0.1-1.5 millimole (mmol) amounts per vinylic group. In one example, the reaction conditions may comprise bromination at the vinylic groups of the styrenic (co)polymer resin. In a further example, reaction conditions may comprise reacting the polyvinyl polymer (a styrenic (co)polymer resin) with a halogen source under first reaction conditions effective to provide a first reaction product comprising at least one halogen.

[0030] In further aspects, the reaction conditions can comprise oxidative reaction conditions, or an oxidation reaction. In still further aspects, the reaction conditions comprise reacting a reactant, or a reaction product, in the presence of an oxidizing agent. Exemplary oxidizing agents may include hydrogen peroxide and tert-butylperoxide among others including dimethyl sulfoxide. In further aspects, the reaction conditions comprise reacting a reaction product comprising at least one styrenic (co)polymer resin in the presence of an oxidizing agent to provide a ketoaldehyde functionalized styrenic (co)polymer (or a phenylglyoxal polymer). In yet further aspects, the reaction conditions comprise reacting a reaction product in the presence of an oxidizing agent, for example, reacting a reaction product in the presence of sodium bicarbonate and iodine in dimethylsulfoxide. In further aspects, the reaction conditions may comprise reacting a halogenated (brominated) reaction product in the presence of sodium bicarbonate and dimethylsulfoxide. As an example, reaction conditions may comprise reacting a brominated styrenic (co)polymer resin in dimethyl sulfoxide with sodium bicarbonate under reaction conditions effective to provide a reaction product comprising at least one glyoxal group with a loading of up to about 3 mmol/g.

[0031] In one aspect, the polyvinyl polymer may be reacted under first, second, and third reaction conditions to provide a reaction product comprising at least one glyoxal group with a loading of up to about 3 mmol/g. The polyvinyl polymer may react under first reaction conditions effective to provide a first reaction product comprising at least one epoxy group. As an example, the polyvinyl polymer, such as the styrenic (co)polymer resin may undergo epoxidation to provide a first reaction product comprising at least one epoxy group. The first reaction product may be reacted under second reaction conditions effective to provide a second reaction product. The second reaction conditions may comprise an epoxy ring opening reaction. As such, the second reaction conditions may be effective to provide, for example, a second reaction product comprising a diol, or a hydroxy bromo-substituted second reaction product, or a di-bromo substituted second reaction product. The second reaction product may react under second reaction conditions to provide a third reaction product comprising at least one glyoxal group with a loading of up to about 3 mmol/g. As an example, the second reaction product may undergo oxidation as the second reaction conditions to form a phenylglyoxal (or alpha-ketoaldehyde styrenic) polymer.

[0032] In further aspects, the polyvinyl polymer may be reacted under first and second reactions conditions to provide a second reaction product comprising at least one glyoxal group with a loading of up to about 3 mmol/g. A polyvinyl polymer may react under first reaction conditions effective to provide a di-halogen derivative. Accordingly, the first reaction conditions may comprise bromination of the styrenic (co)polymer resin to provide a di-bromoethyl functionalized styrenic (co)polymer. The resultant di-bromo resin polymer may undergoes second reaction conditions to provide the second reaction product comprising at least one glyoxal group with a loading of up to 3 mmol/g. The second reaction conditions may include oxidation to convert the di-bromoethyl substituted styrenic (co)polymer resin to a phenylgloxal functionalized styrenic (co)polymer resin having glyoxal group loading of up to about 3 mmol/g.

[0033] In yet further aspects, the polyvinyl polymer may be reacted under first reaction conditions to provide a reaction product comprising at least one glyoxal group with a loading of up to 3 mmol/g. The first reaction conditions may comprise equimolar, or sub-equimolar, amount of a halogen source and a solvent. Sub-equimolar may refer to less than equimolar. It also may comprise the use of equimolar or excess of a co-oxidizer and a base. The halogen source may be selected from, but is not limited to bromine, iodine, N-bromosuccinimide, lithium bromide, and potassium iodide. As an example, and not to be limiting, the solvent may comprise dimethylsulfoxide and its mixtures with water or mixable organic solvents, i.e. alcohols, ketones, dimethylformamide (DMF), and dimethylacetamide (DMA). A suitable base may comprise but is not limited to sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium carbonate, cesium carbonate, linear or cyclic, i.e. N-alkylpiperidine, tertiary amines. The co-oxidizer may comprise, but is not limited to, hydrogen peroxide, tert- butyl peroxide, perbenzoic acid, substituted perbenzoic acid, peracetic acid, oxone, iodosylbenzene, diacyl iodosobenzene, and any combinations thereof.

[0034] In various aspects, the method can further comprise purification of the reaction product. In further aspects, the reaction product is subjected to at least one purification step. In further aspects, the reaction product is purified under conditions effective to provide purified reaction product comprising at least 90 wt. % polymer sorbent. In still further aspects, the purified reaction product comprises from about 90 to about 100 wt. % polymer sorbent, including exemplary values of 91, 92, 93, 94, 95, 96, 97, 98, and 99 wt. %.

[0035] In further aspects, the purification can further comprise the step of filtering, separating, washing, extraction, or drying, or a combination thereof. In still further aspects, purification can comprise filtering, extracting, and washing the product with portions of methanol.

[0036] In various aspects, the method can further comprise separation of the reaction product. In further aspects, the reaction product is subjected to at least one separation step.

[0037] The compounds of this disclosure can be prepared by the disclosed methods employing reactions as shown in the disclosed schemes, in addition to other standard manipulations that are known in the literature, exemplified in the experimental sections or clear to one skilled in the art. The following examples are provided so that the disclosure might be more fully understood, are illustrative only, and should not be construed as limiting. For clarity, examples having a fewer substituent can be shown where multiple substituents are allowed under the definitions disclosed herein.

[0038] It is contemplated that each disclosed method can further comprise additional steps, manipulations, and/or components. It is also contemplated that any one or more step, manipulation, and/or component can be optionally omitted from the disclosure. It is understood that a disclosed method can be used to provide the disclosed compounds. It is also understood that the products of the disclosed methods can be employed in the disclosed compositions, methods, and uses.

1. SYNTHESIS ROUTE 1

[0039] In one aspect, astyrenic (co)polymer, is epoxidized at a temperature effective and for a time effective to produce epoxy group, which in turn can readily undergo epoxide ring opening or hydroxybromination. The resultant compound may be oxidized at a temperature effective and for a time effective to give the corresponding glyoxal polymer.

2. 2

[0040] In one aspect, a styrenic (co)polymeris brominated at a temperature and for a time effective to produce a di-bromo derivative. The resultant compound may be oxidized at a temperature effective and for a time effective to provide the corresponding glyoxal polymer. 3. SYNTHESIS

[0041] In one aspect, a styrenic (co)polymeris reacted at a temperature effective and for a time effective to produce a phenylgloxal polymer. As an example, a vinylbenzene polymer may be reacted with an equimolar or sub-equimolar amount of a halogen source and a solvent to produce phenylglyoxal polymer. In another example, the reaction may further optionally include equimolar amount or excess of co-oxidizer and base to produce phenylglyoxal polymer.

[0042] All the intermediates and the product formation were confirmed with Fourier Transform Infrared Spectroscopy (FTIR) and elemental analysis.

[0043] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class. Unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0044] Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this pertains. The references disclosed are also individually and specifically incorporated by reference herein for the material contained in them that is discussed in the sentence in which the reference is relied upon. Nothing herein is to be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0045] The present disclosure can be understood more readily by reference to the following detailed description of the disclosure and the Examples included therein.

[0046] Before the present compounds, compositions, articles, systems, devices, and/or methods are disclosed and described, it is to be understood that they are not limited to specific synthetic methods unless otherwise specified, or to particular reagents unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, example methods and materials are now described.

[0047] Moreover, it is to be understood that unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; and the number or type of aspects described in the specification.

[0048] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. C. DEFINITIONS

[0049] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. As used in the specification and in the claims, the term "comprising" can include the aspects "consisting of and "consisting essentially of." Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined herein.

[0050] As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a polycarbonate polymer" includes mixtures of two or more polycarbonate polymers.

[0051] As used herein, the term "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0052] Ranges can be expressed herein as from one value (first value) to another value (second value). When such a range is expressed, the range includes in some aspects one or both of the first value and the second value. Similarly, when values are expressed as approximations, by use of the antecedent 'about,' it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as "about" that particular value in addition to the value itself. For example, if the value "10" is disclosed, then "about 10" is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 1 1 , 12, 13, and 14 are also disclosed.

[0053] As used herein, the terms "about" and "at or about" mean that the amount or value in question can be the designated value, approximately the designated value, or about the same as the designated value. It is generally understood, as used herein, that it is the nominal value indicated ±10% variation unless otherwise indicated or inferred. The term is intended to convey that similar values promote equivalent results or effects recited in the claims. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but can be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, an amount, size, formulation, parameter or other quantity or characteristic is "about" or "approximate" whether or not expressly stated to be such. It is understood that where "about" is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0054] As used herein, the terms "optional" or "optionally" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. For example, the phrase "optionally substituted alkyl" means that the alkyl group can or cannot be substituted and that the description includes both substituted and unsubstituted alkyl groups.

[0055] Disclosed are the components to be used to prepare the compositions of the disclosure as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C are disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively

contemplated meaning combinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application including, but not limited to, steps in methods of making and using the compositions of the disclosure. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific aspect or combination of aspects of the methods of the disclosure.

[0056] References in the specification and concluding claims to parts by weight of a particular element or component in a composition or article, denotes the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight component Y, X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.

[0057] As used herein the terms "weight percent," "wt%," and "wt. %," which can be used interchangeably, indicate the percent by weight of a given component based on the total weight of the composition, unless otherwise specified. That is, unless otherwise specified, all wt. % values are based on the total weight of the composition. It should be understood that the sum of wt. % values for all components in a disclosed composition or formulation are equal to 100.

[0058] Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valence filled by a bond as indicated, or a hydrogen atom. A dash ("-") that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -CHO is attached through carbon of the carbonyl group. Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this disclosure belongs.

[0059] The term "alkyl group" as used herein is a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n propyl, isopropyl, n butyl, isobutyl, t butyl, pentyl, hexyl, heptyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like. A "lower alkyl" group is an alkyl group containing from one to six carbon atoms.

[0060] The term "aryl group" as used herein is any carbon-based aromatic group including, but not limited to, benzene, naphthalene, etc. The term "aromatic" also includes "heteroaryl group," which is defined as an aromatic group that has at least one heteroatom incorporated within the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one or more groups including, but not limited to, alkyl, alkynyl, alkenyl, aryl, halide, nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylic acid, or alkoxy.

[0061] The term "alkenyl" as used herein is a monovalent group characterized by C _n H _2n -i, formed from an alkene by removal of one hydrogen atom from any carbon atom.

[0062] The term "vinyl" as used herein is a univalent hydrocarbon group characterized by CH2=CH. The term "polyvinyl" refers to a structure comprising multiple vinyl moieties.

[0063] The term "carbonate group" as used herein is represented by the formula OC(0)OR, where R can be hydrogen, an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above.

[0064] The term "oxirane," or "oxiranyl group," as used herein refers to ethylene oxide and is a cyclic ether comprising two carbon atoms. The term "oxiranyl group: as used herein is synonymous with epoxy group and is represented by the formula C2H ₃ O.

[0065] The term "glyoxal group" as used herein is represented by the formula C2H2O2 and is a representative bisaldehyde moiety.

O _. H

H H O

[0066] The term "phenylglyoxal group" as used herein is represented by the formula

CgH ₆ 02 and is a representative bisaldehyde moiety.

[0067] The term "organic residue" def oines a carbon containing residue, i.e., a residue comprising at least one carbon atom, and includes but is not limited to the carbon-containing groups, residues, or radicals defined hereinabove. Organic residues can contain various heteroatoms, or be bonded to another molecule through a heteroatom, including oxygen, nitrogen, sulfur, phosphorus, or the like. Examples of organic residues include but are not limited alkyl or substituted alkyls, alkoxy or substituted alkoxy, mono or di-substituted amino, amide groups, etc. Organic residues can preferably comprise 1 to 18 carbon atoms, 1 to 15, carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. In a further aspect, an organic residue can comprise 2 to 18 carbon atoms, 2 to 15, carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, 2 to 4 carbon atoms, or 2 to 4 carbon atoms.

[0068] A very close synonym of the term "residue" is the term "radical," which as used in the specification and concluding claims, refers to a fragment, group, or substructure of a molecule described herein, regardless of how the molecule is prepared. For example, a 2,4- dihydroxyphenyl radical in a particular compound has the structure:

regardless of whether 2,4-dihydroxyphenyl is used to prepare the compound. In some aspects the radical (for example an alkyl) can be further modified (i.e., substituted alkyl) by having bonded thereto one or more "substituent radicals." The number of atoms in a given radical is not critical to the present disclosure unless it is indicated to the contrary elsewhere herein.

[0069] "Organic radicals," as the term is defined and used herein, contain one or more carbon atoms. An organic radical can have, for example, 1-26 carbon atoms, 1 -18 carbon atoms, 1-12 carbon atoms, 1 -8 carbon atoms, 1-6 carbon atoms, or 1 -4 carbon atoms. In a further aspect, an organic radical can have 2-26 carbon atoms, 2-18 carbon atoms, 2-12 carbon atoms, 2-8 carbon atoms, 2-6 carbon atoms, or 2-4 carbon atoms. Organic radicals often have hydrogen bound to at least some of the carbon atoms of the organic radical. One example, of an organic radical that comprises no inorganic atoms is a 5, 6, 7, 8-tetrahydro-2- naphthyl radical. In some aspects, an organic radical can contain 1-10 inorganic heteroatoms bound thereto or therein, including halogens, oxygen, sulfur, nitrogen, phosphorus, and the like. Examples of organic radicals include but are not limited to an alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, mono-substituted amino, di-substituted amino, acyloxy, cyano, carboxy, carboalkoxy, alkylcarboxamide, substituted alkylcarboxamide,

dialkylcarboxamide, substituted dialkylcarboxamide, alkylsulfonyl, alkylsulfinyl, thioalkyl, thiohaloalkyl, alkoxy, substituted alkoxy, haloalkyl, haloalkoxy, aryl, substituted aryl, heteroaryl, heterocyclic, or substituted heterocyclic radicals, wherein the terms are defined elsewhere herein. A few non-limiting examples of organic radicals that include heteroatoms include alkoxy radicals, trifiuoromethoxy radicals, acetoxy radicals, dimethylamino radicals and the like.

[0070] The terms "residues" and "structural units", used in reference to the constituents of the polymers, are synonymous throughout the specification.

[0071] As used herein the terms "weight percent," "wt%," and "wt. %," which can be used interchangeably, indicate the percent by weight of a given component based on the total weight of the composition, unless otherwise specified. That is, unless otherwise specified, all wt. % values are based on the total weight of the composition. It should be understood that the sum of wt. % values for all components in a disclosed composition or formulation are equal to 100.

[0072] Each of the materials disclosed herein are either commercially available and/or the methods for the production thereof are known to those of skill in the art.

[0073] It is understood that the compositions disclosed herein have certain functions.

Disclosed herein are certain structural requirements for performing the disclosed functions, and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.

D. ASPECTS

[0074] The disclosed compositions and methods include at least the following aspects.

[0075] Aspect 1. A method for preparing a polymer sorbent, the method comprising:

reacting a polyvinyl polymer under first reaction conditions effective to provide a first reaction product comprising at least one epoxy group; reacting the first reaction product under second reaction conditions effective to provide a second reaction product; and reacting the second reaction product under third reaction conditions to provide a third reaction product comprising at least one glyoxal group with a loading of up to about 3mmol/g.

[0076] Aspect 2. The method of aspect 1 , wherein the first reaction conditions comprise epoxidation or oxirane group formation.

[0077] Aspect 3. The method of any one of aspects 1 -2, wherein the second reaction conditions comprise epoxide ring opening or hydroxybromination.

[0078] Aspect 4. The method of any one of aspects 1 -3, wherein the third reaction conditions comprises oxidation.

[0079] Aspect 5. The method of any one of aspects 1 -4, wherein the polyvinyl polymer is a divinyl benzene having a structure represented by either of the formulas:

wherein R is each independently selected from hydrogen, C 1-C3 alkyl, aryl, substituted alkyl, formyl, carbonyl, carboxyl, carboxylate, hydroxyl and its derivatives.

[0080] Aspect 6. The method of any one of aspects 1 -5, wherein the polyvinyl polymer is a divinyl benzene (co)polymer with a divinyl benzene content between 50 wt. % and 100 wt. %.

[0081] Aspect 7. The method of any one of aspects 1 -6, wherein the third reaction product comprises a phenylglyoxal polymer.

[0082] Aspect 8. The method of any one of aspects 1-7, further comprising directing a dialysate through a membrane comprising the third reaction product to regenerate the dialysate.

[0083] Aspect 9. A method for preparing a polymer sorbent, the method comprising:

reacting a polyvinyl polymer under first reaction conditions effective to provide a first reaction product comprising at least one halogen; and reacting the first reaction product under second reaction conditions to provide a second reaction product comprising at least one glyoxal group with a loading of up to about 3mmol/g.

[0084] Aspect 10. The method of aspect 9, wherein the polyvinyl polymer is a divinyl benzene having a structure represented by either of the formulas:

wherein R is each independently selected from hydrogen, C 1-C3 alkyl, aryl, substituted alkyl, formyl, carbonyl, carboxyl, carboxylate, hydroxyl and its derivatives.

[0085] Aspect 11. The method of any one of aspects 9-10, wherein the first reaction conditions comprise bromination.

[0086] Aspect 12. The method of any one of aspects 9-11 , wherein the second reaction conditions comprise oxidation.

[0087] Aspect 13. The method of any one of aspects 9-12, further comprising directing a dialysate through a membrane comprising the second reaction product to regenerate the dialysate.

[0088] Aspect 14. A polymeric phenylglyoxal resin comprising at least one glyoxal group with a loading of up to about 3mmol/g, the polymeric phenylglyoxal resin produced by a process comprising reacting a polyvinyl polymer.

[0089] Aspect 15. The polymeric phenylglyoxal resin of aspect 14, wherein the process comprises one or more of acetylation, bromination, and oxidation.

[0090] Aspect 16. The polymeric phenylglyoxal resin of aspect 14, wherein the process comprises reacting the polyvinyl (co)polymer with an equimolar or sub-equimolar amount of a halogen source and solvent.

[0091] Aspect 17. The polymeric phenylglyoxal resin of any one of aspects 14-16, wherein the polymeric phenylglyoxal resin comprises glyoxal or gly oxalic acid units.

[0092] Aspect 18. The polymeric phenylglyoxal resin of aspect 17, wherein the glyoxal or glyoxalic acid units are attached to meta- and/or para-positions of the polymer chain.

[0093] Aspect 19. A composition comprising the polymeric phenylglyoxal resin of any one of aspects 14-18, wherein the composition exhibits mean pore size of 14 to 1000 Angstrom, pore volume of 0.3 to 1.85 mL/g and surface area by nitrogen surface area (NSA) of 150-

1 100 m ² /g.

E. EXAMPLES

[0094] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. Unless indicated otherwise, percentages referring to composition are in terms of wt. %.

4. GENERAL METHODS

[0095] All materials and reagents were used as is unless otherwise indicated.

[0096] The urea sorption measurements were performed in aqueous buffer solutions prepared according to the following procedure.

[0097] Sodium chloride (5.80 g), CaCl ₂ (333 mg), KC1 (149 mg), MgCl ₂ (71 mg), dextrose (2.00 g), NaHCCb (2.77 g), and urea (2.00 g) were dissolved in approximately 500 milliliters (mL) of deionized water in a 1000 mL volumetric flask. Glacial acetic acid (50 mL) was slowly added to the flask and gently swirled until all of the salts are dissolved. The flask was filled to the mark with deionized water resulting in solution A. The buffer solution without urea, solution B, was prepared in the similar manner.

[0098] The above solution A (100 mL) was added to the sorbent sample (1 gram (g)) and the vial was shaken for 24 hours. The 1.7 mL aliquot of the solution was diluted with 2.5 mL of buffer solution B followed by 0.8 mL of a dimethylaminobenzaldehyde (DMABA) solution prepared from 0.8 g of DMABA, 2 mL of concentrated HC1 and 18 mL of the buffer solution B. The ultraviolet (UV) absorbance at 420 nanometers (nm) UV was measured to calculate the urea content from the calibration curve data.

5. SYNTHESIS OF INTERMEDIATES/COMPOUNDS

Conversion of DVB copolymer to Functionalized Styrenic (co)Polymer

[0099] Example 1: Epoxy Substituted (co)Polymers

[00100] A 100 mL scintillation vial equipped with a magnetic stirring bar was charged with 20 ml of acetic anhydride and 6 g of styrenic resin having a surface area of 725 square meters per gram (m ² /g) and an average pore diameter of 50 A. The mixture was cooled to 0 degrees Celsius (°C) and hydrogen peroxide (2 mL, 40% aqueous solution) was added and the reaction mixture was stirred at 10-15 °C for 8 hours. The resultant resin was filtered, washed with acetic acid in two 100 mL portions, washed with methanol (100 mL) and dried in a vacuum oven at 70 °C overnight. The resin had an infrared (IR) frequency of 1250 inverse centimeters (cm ^-1 ) and 870 cm ^"1 as determined by an FTIR analysis.

[00101] Example 2: 1,2-Dihydroxyethyl Substituted (co)Polymers

[00102] A 100 mL scintillation vial equipped with a magnetic stirring bar was charged with 2 g of the above epoxy-modified copolymer from Example 1, swollen in glacial acetic acid (20 mL). 2 mL of water and 2 drops of concentrated sulfuric acid were added, and the reaction mixture was heated under stirring 50-70 °C for 5 hours, thus converting epoxy groups into diol groups. The resultant resin was filtered, washed with acetic acid in two 100 mL portions, washed with methanol (100 mL) and dried in a vacuum oven at 70 °C overnight. The resin had an IR frequency of 3310-3190 cm ^"1 as determined by an FTIR analysis.

[00103] Example 3: l-Hydroxy-2-bromoethyl Substituted (co)Polymers

[00104] A 100 mL scintillation vial equipped with a magnetic stirring bar was charged with 2 g of the above epoxy-modified copolymer from Example 1, swollen in glacial acetic acid (20 mL). 2 mL HBr (48% aqueous solution) was added and the reaction mixture was heated under stirring 50-70 °C for 5 hours, thus converting epoxy groups into bromohydrin groups. The resultant resin was filtered, washed with acetic acid in two 100 mL portions, washed with methanol (100 mL) and dried in a vacuum oven at 70 °C ovemight. The resin had an IR frequency of 3600-3200 cm ^"1 as determined by an FTIR analysis and a di-molecular bromine (Br ₂ ) content of 11.95 wt. %.

[00105] Example 4: Ketoaldehyde Functionalized Styrenic (co)Polymer from Diol Resin

[00106] A 100 mL scintillation vial equipped with a magnetic stirring bar was charged with 2 g of the above diol-modified copolymer from Example 2, swollen in chloroform (20 mL). Iodoxy benzoic acid was added (1.4 g, 5 mmol) and the reaction mixture was heated under stirring 50-70 °C for 5 hours, thus converting diol groups into ketoaldehyde. The resultant resin was filtered, washed with chloroform in two 100 mL portions, washed with methanol (2 x 100 mL) and dried in a vacuum oven at 70 °C ovemight. The resin had an IR frequency of 1850-1590 cm ^"1 as determined by an FTIR analysis and a urea sorption capacity of 11.2 grams per kilogram (g/kg). [00107] Example 5: Ketoaldehyde Functionalized Styrenic (co)Polymer from 1- Hydroxy-2-bromoethyl Substituted (co)Polymer

[00108] A 100 ml vial equipped with a magnetic stirring bar was charged with 2 g of the resin of Example 3, suspended in 40 ml of dimethylsulfoxide. Sodium bicarbonate (1.68 g, 20 mmol) was added in a single portion to each vial. The vials were capped and the contents stirred at 100 °C for six hours. The resultant resin was filtered, washed with methanol in five 20 ml portions, and dried in a vacuum oven at 70 °C. The resin had an IR frequency of 1850- 1590 cm ^"1 as determined by an FTIR analysis and a urea sorption capacity of 12.4 g/kg.

[00109] Example 6: 1,2-Dibromoethyl Substituted (co)Polymers

[00110] A 40 ml scintillation vial equipped with a magnetic stirring bar was charged with 2g styrenic resins in 20 ml chloroform. A sample of 5.6 ml of bromine was dissolved in 80 ml chloroform to provide a 1.4 molar (M) bromine solution. The bromine solution was added in one 4 ml portion to each scintillation vial. The scintillation vials were capped and the contents stirred at room temperature for three 8 hour intervals for a total of 24 hours. The resultant resin was filtered, washed with methanol in two 100 ml portions, and dried in a vacuum oven at 70 °C overnight. The resin had a Br ₂ content of 23.14 wt. %.

[00111] Example 7: Ketoaldehyde Functionalized Styrenic (co)Polymer from 1,2- Dibromoethyl Resin

[00112] A 100 ml vial equipped with a magnetic stirring bar was charged with 2 g of the Example 6 resin, suspended in 40 ml of dimethylsulfoxide. Sodium bicarbonate (1.68 g, 20 mmol) was added in a single portion to each vial. The vials were capped and the contents stirred at 100 °C for six hours. The resultant resin was filtered, washed with methanol in five 20 ml portions, and dried in a vacuum oven at 70 °C. The resin had an IR frequency of 1850-1590 cm ^"1 as determined by an FTIR analysis and a urea sorption capacity of 15.4 g/kg.

[00113] Example 8: Ketoaldehyde Functionalized Styrenic (co)Polymer from Styrenic Resin

[00114] A 40 ml scintillation vial equipped with a magnetic stirring bar was charged with polymer resin XAD-4 (approximately 5 mmol) in 20 ml of dimethylsulfoxide. Iodine (1 mmol, 0.25 g) and sodium bicarbonate (1.26 g, 15 mmol) were added in a single portion to each vial. The vials were capped and the contents stirred for eight hours at 110 °C. The vials were cooled to room temperature and the resultant resins were filtered, washed with two 100 ml portions of methanol, and dried in a vacuum oven at 70 °C. The resin had an IR frequency of 1850-1590 cm ^"1 as determined by an FTIR analysis and a urea sorption capacity of 18.2 g kg.

[00115] There are numerous variations and combinations of reaction conditions, e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures and other reaction ranges and conditions that can be used to optimize the product purity and yield obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions.

[00116] It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. Other aspects of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

[00117] The patentable scope of the disclosure is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.