WO1996037535A1

WO1996037535A1 - Method of preparing poly(phenylene oxides) in carbon dioxide

Info

Publication number: WO1996037535A1
Application number: PCT/US1996/007268
Authority: WO
Inventors: Joseph M. Desimone; Chad D. Mistele; Kerstin K. Kapellen
Original assignee: The University Of North Carolina At Chapel Hill
Priority date: 1995-05-25
Filing date: 1996-05-20
Publication date: 1996-11-28
Also published as: AU5865796A

Abstract

The present invention provides a process for making poly(phenylene oxide) polymers. The process includes (a) contacting a phenol monomer with a catalyst capable of catalyzing the polymerization of the phenol monomer, and a polymerization medium including carbon dioxide; and (b) polymerizing the monomer. The polymerization medium may include gaseous, liquid, or supercritical carbon dioxide.

Description

METHOD OF PREPARING POLY(PHENYLENE OXIDES) IN CARBON DIOXIDE

Field of the Invention

The present invention relates to a method of preparing poly(phenylene oxides), and particularly to a method of preparing polyφhenylene oxides) in a medium comprising carbon dioxide.

Background of the Invention

Poly(phenylene oxide) polymers are known to possess desirable physical and chemical properties for a variety of applications, and various methods for their preparation have been proposed. For example, U.S. Patent No. 3,236,807 to Stamatoff proposes a method for preparing high molecular weight poly(unsymmetrically-2,6-disubstituted phenylene ether) including polymerizing a halophenol in the presence of oxygen and a free radical initiator in an organic solvent such as aromatic hydrocarbons, ethers, and halogenated hydrocarbons. U.S. Patent Nos. 3,306,874 and 3,306,875 to Hay propose methods of oxidizing phenols for the preparation of poly(phenylene oxides) with oxygen and an amine-basic cupric salt complex is solubilized with the phenol.

U.S. Patent No. 3,431,238 to Borman proposes a method of oxidizing halophenols using a basic cupric salt and an amine in a solvent such as benzene or toluene. U.S. Patent No. 3,573,257 to Nakashio et al., proposes a process for producing poly(phenylene oxides) which includes polymerizing a phenol in the presence of a copper compound, an alcoholate and/or phenolate of an alkali metal, preferably in an organic solvent. U.S. Patent Nos. 3,639,656 to Bennett et al. and 3,661,848 to Cooper et al., propose a method for preparing poly(phenylene ethers) including oxidatively coupling a phenol in the presence of a non-basic cupric salt and an amine in an alcoholic solvent. U.S. Patent No. 3,965,069 to Olander proposes a method for preparing poly(phenylene oxide) using manganese chelate catalysts in a basic reaction medium such as an alkali metal hydroxide. U.S. Patent No. 4,035,357 to Cooper et al. proposes a process for preparing poly(phenylene ethers) in methylene chloride. U.S. Patent No. 4,092,294 to Bennett, Jr. et al., proposes a method for preparing polyφhenylene ethers) by oxidatively coupling a phenol in the presence of a copper complex in a mixture of toluene and methanol. U.S. Patent No.

4,110,312 to Banucci et al., proposes a method for preparing polyφhenylene oxides) using a manganese-vinyl resin complex as a catalyst in organic solvents such as toluene.

Each of the foregoing methods have in common the use of an organic solvent as polymerization medium. The disadvantage of such polymerization systems is due in part to the fact that organic solvents may be detrimental to the environment. Accordingly, there remains a need in the art for a method of preparing poly(phenylene oxide) polymers which avoids the use of organic solvents. There is also a need in the art for polyφhenylene oxide) polymerization processes capable of commercialization, which may be carried out in relatively "inexpensive solvents which are easily separable from the polymer produced.

Summary of the Invention

As a first aspect, the present invention provides a process for making poly(phenylene oxide) polymers. The process includes (a) providing a polymerization medium comprising carbon dioxide (b) contacting a phenol monomer with a catalyst capable of catalyzing the polymerization of the phenol monomer, in the polymerization medium; and (c) polymerizing the monomer in the polymerization medium. As used herein, the term "phenol monomer" refers to substituted phenol compounds. Substituted phenol compounds which are useful as phenol monomers include phenol compounds subsituted one or more times with any of H, halogen, alkyl, substituted alkyl, alkoxy, phenyl, phenoxy, carboxy, alkyl substituted carboxy, and perfluoroalkyl. The phenol monomers useful in the methods of the present invention typically have the formula (I):

wherein R_l5 R₂, R₄, and R_$ are independently selected from the group consisting of H, halogen, alkyl, substituted alkyl, alkoxy, phenyl, phenoxy, carboxy, alkyl substituted carboxy, and perfluoroalkyl; and R₃ is selected from the group consisting of H and halogen. The carbon dioxide useful as the polymerization medium may be in the form of liquid, supercritical, or gaseous carbon dioxide. Catalysts useful in the methods of the present invention are typically multi- component systems comprising (1) a transition metal salt, (2) an amine, and (3) oxygen. In one preferred embodiment, the polymerization is carried out in the presence of a surfactant. Advantageously the process may also include the steps of separating the poly(phenylene oxide) polymer from the polymerization medium.

As a second aspect, the present invention provides a process for preparing a poly(phenylene oxide) copolymer. The process includes (a) contacting a phenol monomer and a comonomer with a catalyst capable of catalyzing the copolymerization of the phenol monomer and comonomer, and a polymerization medium including carbon dioxide; and (b) copolymerizing the phenol monomer and comonomer.

As a third aspect, the present invention provides a polymerization reaction mixture useful for carrying out the polymerization of a phenol monomer. The reaction mixture includes (a) a phenol monomer, (b) a catalyst capable of catalyzing the polymerization of a phenol monomer, and (c) a polymerization medium comprising carbon dioxide.

As a fourth, the present invention provides a mixture produced by the polymerization of a phenol monomer. The mixture includes (a) a polyφhenylene oxide) polymer, and (b) a polymerization medium comprising carbon dioxide. Carbon dioxide has been employed as a reaction medium for the polymerization of various monomers. For example, U.S. Patent No. 3,522,228 to Fukui et al. , proposes the polymerization of vinyl monomers in liquid carbon dioxide using hydrocarbon polymerization initiators. U.S. Patent No. 5,328,972 to Dada et al., proposes a process for preparing low molecular weight polymers in supercritical carbon dioxide. U.S. Patent No. 3,471,463 to Kagiya et al., proposes the polymerization of ethylene in carbon dioxide, using a radical initiator compound. U.S. Patent No. 5,312,882 and 5,382,623 to DeSimone et al. , disclose the heterogeneous polymerization of water-insoluble polymers in carbon dioxide. PCT Publication No. WO 93/20116 to the

University of North Carolina at Chapel Hill discloses processes for making fluoropolymers which include solubilizing a fluoromonomer in a solvent comprising carbon dioxide. The use of carbon dioxide in such systems is advantageous in that it provides an inexpensive solvent system, which is environmentally compatible, and easily separable from the polymers produced.

However, none of the foregoing references discuss the use of carbon dioxide as a polymerization medium for the preparation of poly(phenylene oxide) polymers.

The foregoing and other aspects of the present invention are explained in detail in the detailed description set forth below.

Detailed Description of the Invention

As used herein, the term "alkyl" refers to linear or branched, saturated or unsaturated Cj to C₁₀ hydrocarbon groups, such as for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, hexyl, octyl, and the like. This definition also applies to the alkoxy moiety, thus examples of alkoxy substituents include methoxy, ethyoxy, propoxy, butoxy, and the like. The terms "halogen" or "halo" or "halide" as used herein refers to a halogen such as fluorine, chlorine, bromine and iodine. As used herein, the term "supercritical" has its conventional meaning in the art. A supercritical fluid (SCF) is a substance above its critical temperature and critical pressure (or

"critical point"). Compressing a gas normally causes a phase separation and the appearance of a separate liquid phase. However, if the fluid is in a supercritical state, compression will only result in density increases; no liquid phase will be formed. The critical temperature of carbon dioxide is about 31°C. The term "fluoropolymer" as used herein has its conventional meaning in the art.

The phenol monomers useful in the processes of the present invention include phenol monomers which are known to those skilled in the art. Typically, the phenol monomers useful in the methods of the present invention include monomers having the Formula (I):

wherein R*,, R₂, R₄, and R₅ are independently selected from the group consisting of H, halogen, alkyl, substituted alkyl, alkoxy, phenyl, phenoxy, carboxy, alkyl substituted carboxy, and perfluoroalkyl; and R₃ is selected from the group consisting of H and halogen. Examples of sutiable phenol monomers having the formula (I) include, but are not limited to 2,6-dimethyl phenol, 2,6-diethyl phenol, 2,6-dibutyl phenols, 2,6-dilauryl phenol, 2,6-dipropyl phenols, 2,6- diphenyl phenol, 2-methyl-6-ethyl phenol, 2-methyl-6-propargyl phenol, 2- methyl-6-cyclohexyl phenol, 2-methyl-6-benzyl phenol, 2-methyl-6-tolyl phenol, 2-methyl-6-methoxy phenol, 2-ethyl-6-phenylethyl phenol, 2,6-dimethoxy phenol, 2,3,6-trimethyl phenol, 2,3,5,6-tetramethyl phenol, 2,6-diethoxy phenol, 2-methoxy-6-ethoxy-phenol, 2-ethyl-6-stearyloxy phenol, 2,6-di- (chlorophenoxy) phenols, 2-6-dimethyl-3-chloro phenol, 2-methyl-6-bromo phenol, 2-methyl-4-chloro-6-bromo phenol, 2,3,5-trimethyl-6-chloro phenol, 2,6-dimethyl-4-chloro phenol, 2,6-dimethyl-3-chloro-5-bromophenol, 2.6-di- (chloroethyl) phenol, 2-methyl-6-isobutyl phenol, 2-methyl-6-phenylphenol, 2,6- dibenzyl phenol, 2,6-ditolyl phenol, 2.6-di-(chloropropyl) phenol, 2,6-di-(2',4'- dichlorophenol)-3-allyl phenol, and the like. One preferred phenol monomer for use in the methods of the present invention is 2,6-dimethyl phenol.

The poly(phenylene oxide) polymers produced according to the methods of the present invention include homopolymers of any of the foregoing phenol monomers, or in the embodiment wherein one or more comonomers are employed in combination with the phenol monomer, the resulting poly henylene oxide) polymers may be copolymers. The poly(phenylene oxide) polymers typically have the Formula (II):

wherein R_l5 R₂, R₄, and R₅ are as defined above in connection with Formula

(I).

Specific examples of homopolymers produced according to the methods of the present invention include but are not limited to poly(2,6- dimethyl phenol) and poly(2,6-diphenyl phenol). The comonomers useful in the methods of the present invention are typically other phenol monomers, such as for example any of the phenol monomers recited above. Copolymers which may be produced according to the processes of the present invention include but are not limited to:

2,6-dimethyl phenol-co-2,6-diphenyl phenol, 2,6-diphenyl phenol-co-2-methyl-6-phenyl phenol,

2,6-dimethyl phenol-co-3,4,5 tribromo-2,6-dimethyl phenol, and

2,6-dimethyl phenol-co-2,3,6-trimethyl phenol.

The processes of the present invention are generally carried out in the presence of a catalyst capable of catalyzing the polymerization of the phenol monomer, or monomer and comonomer, to produce the poly(phenylene oxide) polymer. Suitable catalysts are known to those skilled in the art, and generally include catalysts for polymerization via oxidative coupling, and catalysts for polymerization via radical-initiated displacement. For example, catalysts which polymerize via oxidative coupling include multi-component catalyst systems such as those described in U.S. Patent Nos. 3,306,874 and 3,306,875 to Hay, 3,431,238 to Borman, 3,573,257 to Nakashio et al. , 3,639,656 to Bennett et al. , 4,028,341 to Hay, 4,092,294 to Bennett, Jr. et al. , and 4,129,555 to White, the disclosures of which are incorporated herein by reference in their entirety. For example, the multi-component catalyst system typically includes a transition metal salt, an amine, and oxygen. The transition metal salt is typically a transition metal halide, such as a transition metal halide of copper, manganese, or cobalt, with copper halides currently being preferred. Preferred copper halide transition metal salts include copper (I) bromide and copper (I) chloride. Other suitable transition metal halides include manganese bromide, manganese chloride, manganese fluoride, manganese iodide, cobalt bromide, cobalt chloride, cobalt fluoride, and cobalt iodide. Other suitable transition metal salts are known to those skilled in the art and include, for example, copper (I) oxide, copper sulfate, manganese (II) carbonate, manganese

(II) sulfate, manganese (II) acetate, manganese (II) nitrate, manganese (II) phosphate, and the like. Preferably, the transition metal salt is selected from copper (I) bromide and copper (I) chloride.

Amines which may be useful as a second component of the multi- component catalyst system include aliphatic monoamines, aliphatic diamines, pyridine, polymeric amines, and copolymers of any of the foregoing with a fluorinated monomer. Examples of suitable aliphatic monoamines are known in the art and include those described in U.S. Patent No. 3,431,238, already incorporated herein by reference. Specifically, examples of suitable aliphatic monoamines include dimethylamine, diethylamine, diisopropylamine, di-n- butylamine, methylethylamine, methylbenzylamine, dibenzylamine, dioctylamine, trimethylamine, triethylamine, trihexylamine, dimethylbenzylamine, methyethylbenzylamine, /.-diethylaminoethanol, dimethylaniline, and the like,. Examples of suitable aliphatic diamines include N,N,N',N'-tetramethylmethylenediamine, N,N,N',N'-tetraamyl-l,2- ethylenediamine, N'-benzyl-N,N-dimethyl-l,2-ethylenediamine, dibenzyl- dimethyl-l,2-ethylenediamine, l,2-ethylene-N,N'-dimorpholine, N,N,N',N'- tetramethyl-1 ,3-propanediamine, N,N,N' ,N' -tetramethyl-1 ,3-butanediamine, and N,N,N',N'-tetramethyl-l,4-butanediamine. Examples of suitable polymeric amines include but are not limited to polyvinylpyridine, and dialkylamino substituted styrenes. Examples of suitable copolymers of amines and fluorinated monomers include but are not limited to poly(2-

(dimethylamino)ethylacrylate-co-perfluorooctylacrylate) , and poly (vinylpyridine- co-perfluorooctylacrylate). Preferred amines include dibutylamine, pyridine, poly(2-(dimethylamino)ethyl-acrylate-co-perfluorooctylacrylate), and poly(vinylpyridine-co-perfluorooctylacrylate). Currently preferred multi-component catalyst systems include copper (I) bromide, dibutylamine, and oxygen; copper (I) bromide, pyridine, and oxygen; copper (I) bromide, poly(2-(dimethylamino)ethylacrylate-co- perfluorooctylacrylate), and oxygen; and copper (I) bromide, poly(vinylpyridine-co-perfluorooctylacrylate), and oxygen. Other suitable catalyst systems known to those skilled in the art include catalyst systems for polymerization via radical-initiated displacement. Such catalyst systems are known in the art, and include those catalysts described in the H. Mark, Encyclopedia of Polvmer Science and Engineering. Wiley Interscience, 13:8 (1988), the disclosure of which is incorporated herein by reference in its entirety. Specific examples of catalysts include but are not limited to potassium ferricyanide, lead dioxide, iodine, and 2,4,6-tri-t- butylphenoxy radicals.

Typically, the catalyst is used in an amount conventionally employed for polymerization. The amount of catalyst employed depends on several factors, including the specific monomers and comonomers to be polymerized, the reactivity of the monomers or comonomers, the reaction conditions, and the particular catalyst chosen. In one preferred embodiment, the phenol monomer is present in an amount of from about 0.1 to about 80 percent by weight, the molar ratio of copper halide to phenol monomer is from about 1:20 up to about 1:300, and the molar ratio of amine to copper halide is from about 1:10 up to about 1:100. The oxygen is present in an amount sufficient to achieve a molar ratio of monomer of oxygen of at least about 1:0.5, and may be added alone or in admixture with the carbon dioxide polymerization medium.

The processes of the invention are carried out in a polymerization medium comprising carbon dioxide. The carbon dioxide may be in a gaseous, liquid or supercritical state. The polymerization medium may also include one or more cosol vents. Illustrative cosol vents include but are not limited to, organic solvents such as methanol, toluene, benzene, and halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, chloroform, trichlorethylene, tetrachloroethylene, and the like. It may be desirable for the cosol vent to be capable of solubilizing the catalyst such that the catalyst may be provided to the reaction in the solubilized form. The catalyst may be added in neat form, or it may conveniently be added as a solution in a cosolvent. Advantageously, the cosolvent may be a styrenic monomer which is capable of polymerization subsequent to the polymerization of the phenol monomer. The sequential polymerization of these components obviates the necessity of mixing in the preparation of polystyrene/poly(phenylene oxide) blends.

The polymerization reaction mixture may include other additives and reactants known to those skilled in the art. For example in one preferred embodiment, the process of the invention includes the addition of surfactant for stabilizing the monomer and polymer in the polymerization medium. The surfactant should be one that is surface active in carbon dioxide and thus partitions itself at the carbon dioxide-monomer or carbon dioxide-polymer interface. Suitable surfactants are described in detail in U.S. Patent No. 5,312,882 to DeSimone et al., the disclosure of which is incorporated herein by reference in its entirety. Such a surfactant may cause the formation of micelles in the carbon dioxide and thus create a dispersed phase. The surfactant is generally present in the reaction mixture in a concentration of from about 0.001 up to about 30 percent by weight. The surfactants can be nonreactive in the polymerization or can react with and thereby be included with the forming polymer. Suitable reactive surfactants include fluorinated and siloxane phenolic monomers. The surfactant should contain a segment that is soluble in carbon dioxide ("CO₂-philic"). Exemplary CO₂-philic segments include a fluorine- containing segment, such as can be found in fluoropolymers or copolymers of fluoropolymers, or a siloxane-containing segment, such as can be found in siloxane polymers or copolymers of siloxane polymers. As used herein, a

"fluoropolymer" has its conventional meaning in the art. Exemplary fluoropolymers are those formed from: fluoroacrylate monomers such as 2-(N- ethylperfluorooctanesulfonamido) ethyl acrylate ("Et-FOSEA"), 2-(N- ethylperfluorooctanesulfonamido) ethyl methacrylate ("EtFOSEMA"), 2-(N- methylperfluorooctanesulfonamido) ethyl acrylate ("MeFOSEA"), 2-(N- methylperfluorooctanesulfonamido) ethyl methacrylate ("MeFOSEMA"), 1,1- Dihydroperfluorooctyl acrylate ("FOA"), and 1,1-Dihydroperfluorooctyl acrylate ("FOMA"); fluoroolefin monomers such as tetrafluoroethylene; fluoroalkylene oxide monomers such as perfluoropropylene oxide and perfluorocyclohexene oxide; fluorinated vinyl alkyl ether monomers; and the copolymers thereof with suitable comonomers, wherein the comonomers are fluorinated or unfluorinated. Exemplary siloxane-containing compounds include alkyl, fluoroalkyl, and chloroalkyl siloxanes.

More preferably, the surfactant comprises a hydrophobic group, such as a polystyrene group or a poly(phenylene oxide) group, that is "CO₂- phobic," along with a CO₂-soluble group, such as a fluoropolymer. Such copolymers can take many forms; two exemplary forms are graft copolymers having a CO₂-soluble backbone and hydrophobic branches attached thereto and block copolymers, including diblock and triblock copolymers, having a central hydrophobic portion attached at opposite ends to one of a pair of CO₂-soluble portions are preferred. When a block copolymer as described above is dissolved in CO₂, the CO₂-soluble end portions extend into the CO₂-continuous phase, but the hydrophobic portions can aggregate to form the core of a micelle. It is particularly preferred that the fluoropolymer segment be a fluorinated acrylate polymer such as dihydroperfluorooctyl acrylate. A preferred block copolymer surfactant comprises poly (1,1 -dihydroperfluorooctyl acrylate) end blocks and a polystyrene center block. Exemplary silicone-containing surfactants (i.e., siloxane polymers or copolymers) include

CH, CH, CH, CH3-(CH2)χ-(Si-0)y-Si— CH-CH_jCHg CH, CH,

wherein x and y are varied to adjust to "CO₂-philic" and "CO₂-phobic" balance. The polymerization reaction may be carried out at a temperature of from about -57°C up to about 250°C, and is typically carried out at a temperature of between about 20°C and about 50°C. The reaction may be carried out at a pressure ranging from about 20 psi to about 10,000 psi, and is typically carried out at a pressure of between about 500 psi and about 5,000 psi. The polymerization is carried out for a period of time sufficient to achieve the polymerization of substantial fraction of the phenol monomer, or monomer and comonomers present. Typically, the reaction mixture is allowed to polymerize for a period of from about 1 to about 24 hours.

The polymerization can be carried out batchwise or continuously with thorough mixing of the reactants in any appropriately designed high pressure reaction vessel. To remove the heat evolved during the polymerization, advantageously the pressure apparatus includes a cooling system. Additional features of the pressure apparatus used in accordance with the invention include heating means such as an electric heating furnace to heat the reaction mixture to the desired temperature and mixing means, i.e., stirrers such as paddle stirrers, impeller stirrers, or multistage impulse countercurrent agitators, blades, and the like.

The polymerization can be carried out, for example, by feeding a mixture of phenol monomer and transition metal salt into a pressure apparatus. The reaction vessel is closed and the amine is added through an injector loop together with a mixture of oxygen and carbon dioxide. Thereafter, the reaction mixture brought to the polymerization temperature and pressure. If desired, a cosolvent, and/or surfactant may be added to the reaction vessel with the transition metal salt and phenol monomer. It is also possible to add the carbon dioxide, and heat the reaction mixture prior to the addition of the amine and oxygen. Alternatively, only a part of the reaction mixture may be introduced into an autoclave and heated to the polymerization temperature and pressure, with additional reaction mixture being pumped in at a rate corresponding to the rate of polymerization. In another possible procedure, some of the phenol monomers are initially taken into the autoclave in the total amount of carbon dioxide and the phenol monomers or comonomers are pumped into the autoclave together with the catalyst at the rate at which the polymerization proceeds. In another possible procedure, the transition metal halide, amine, oxygen, and a portion of the carbon dioxide are added to the reaction vessel, and the mixture is heated prior the addition of the phenol monomer as a solution in carbon dioxide, which brings the reaction mixture to the required reaction temperature and pressure. As will be clear to those skilled in the art, the exact order of addition of the reactants is generally not critical, and those skilled in the art will appreciate that many methods of carrying out the present invention which manipulate the order of addition of the reactants are contemplated by the instant invention in order to optimize the methods of the invention.

When the polymerization is complete the polymer may be separated from the reaction mixture. Any suitable means of separating the polymer from the reaction mixture may be employed. Typically, according to the process of the present invention, the polymer is separated from the reaction mixture by venting the polymerization medium to the atmosphere. Thereafter the polymer may be collected by physical isolation. It may be desirable, for some applications to wash the resulting polymer prior to further processing. The polymer may be washed in wash fluids which are conventionally known in the art. For example, suitable wash fluids include mixtures of methanol and acid such as acetic acid or hydrochloric acid. Alternatively, the polymer may be washed in a wash fluid comprising carbon dioxide.

The poly henylene oxide) polymers produced according to the processes of the present invention are useful in a variety of conventionally known applications. For example, the poly(phenylene oxide) polymer are useful for the production of molded articles including automotive body parts such as instrument panels, interior trim, speaker grills, consoles, glove compartments, exterior trim, cowl tops, wheel covers, headlight housings, mirror cases, electrical connectors, and fuse boxes. In addition, poly(phenylene oxide) polymers are useful for the production of various small appliances such as hair dryers, coffee makers, and steam irons; and large appliances such as refrigerators and ranges. The poly(phenylene oxide) polymers produced according to the methods of the present invention may be combined with other known polymers such as polystyrene for the production of molded articles such as automotive parts and appliances as described above.

The following examples are provided to illustrate the present invention, and should not be construed as limiting thereof. In these examples, "psi" means pounds per square inch; "g" means grams; "mg" means milligrams; "ml" means milliliters; "g/mol" means grams per mole; "min. " means minutes; " °C" means degrees Celsius and "wt. %" means percent by weight. The molecular weights are determined by GPC in toluene using polystyrene as standard.

Example 1 A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 0.6 ml dibutyl amine are added and the reactor is closed. Oxygen is added to a pressure of 274 psi, followed by the addition of carbon dioxide to a pressure of 1600 psi. The solution is stirred while 2,6- dimethyl phenol (DMP), dissolved in carbon dioxide, is added from a variable volume cell. During the addition of the monomer (0.77 g; Cu: amine: DMP

1:22:37) the pressure increases to 4700 psi. After 18 hours stirring at room temperature the carbon dioxide is vented and the product washed with a mixture of 1 % acetic acid in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.25 g (32%) polyphenylene oxide with an average molecular weight of M_n = 3,983 g/mol and a polydispersity of PDI = 1.79.

Example 2 A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 0.6 ml dibutyl amine are added, and the reactor is closed. Oxygen is added to a pressure of 266 psi, followed by the addition of carbon dioxide to a pressure of 850 psi. The solution is stirred while 2,6- dimethyl phenol (DMP), dissolved in carbon dioxide, is added from a variable volume cell. During the addition of the monomer (1.55 g; Cu:amine:DMP 1:22:75) the pressure increases to 4800 psi. After 18 hours stirring at room temperature the carbon dioxide is vented and the product washed with a mixture of 1 % acetic acid in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.123 g (8%) polyphenylene oxide with an average molecular weight of M_n = 5,287 g/mol and a polydispersity of PDI = 1.73.

Example 3 A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 0.6 ml dibutyl amine are added and the reactor is closed. Oxygen is added to a pressure of 360 psi. followed by the addition of carbon dioxide to a pressure of 900 psi. The reactor is heated to 40°C. The solution is stirred while 2,6-dimethyl phenol (DMP), dissolved in carbon dioxide, is added from a variable volume cell. During the addition of the monomer (1.10 g; Cu : amine : DMP = 1 : 22 : 55) the pressure increases to 4900 psi. After 19 h stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1% acetic acid in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.34 g (31 %) polyphenylene oxide with an average molecular weight of M_n = 5,213 g/mol and a polydispersity of PDI = 1.94.

Example 4

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 1.52 g 2,6-dimethyl phenol are added and the reactor is closed. Oxygen is added to a pressure of 360 psi, followed by the addition of carbon dioxide to a pressure of 1500 psi. The cell is heated to 40 °C, resulting in a pressure of 1850 psi. The solution is stirred while 0.6 ml dibutyl amine (Cu: amine: DMP 1:22:75) are added through a injector loop with carbon dioxide, to a final pressure of 5000 psi. After 18 hours stirring at 40°C the carbon dioxide is vented and the product washed with a mixture of 1 % acetic acid in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.35 g (23%) polyphenylene oxide with an average molecular weight of M_n = 3,407 g/mol and a polydispersity of PDI = 2.51.

Example 5

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 1.52 g 2,6-dimethyl phenol are added and the reactor is closed. Oxygen is added to a pressure of 314 psi, followed by the addition of carbon dioxide up to a pressure of 1280 psi. The cell is heated to 40°C, resulting in a pressure of 1680 psi. Carbon dioxide is added up to a pressure of 3000 psi. The solution is stirred while 0.3 ml pyridine (Cu:amine:DMP 1:22:75) are added through an injector loop with carbon dioxide, to a final pressure of 5000 psi. After 1 hour stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1 % acetic acid in methanol.

The product is filtered and precipitated from toluene into methanol. The reaction yields 0.09 g (6%) polyphenylene oxide with an average molecular weight of M_n = 3,372 g/mol and a polydispersity of PDI = 2.33. Example 6

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 1.55 g 2,6-dimethyl phenol are added and the reactor is closed. Oxygen is added to a pressure of 300 psi, followed by the addition of carbon dioxide up to a pressure of 1600 psi. The cell is heated to 40°C and carbon dioxide is added to a pressure of 3000 psi. The solution is stirred while 0.3 ml pyridine (Cu:amine:DMP 1:22:75) are added through an injector loop to a final pressure of 5000 psi. After 24 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1 % acetic acid in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.69 g (45%) polyphenylene oxide with an average molecular weight of M_n = 4,097 g/mol and a polydispersity of PDI = 2.34.

Example 7

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g) and 1.58 g 2,6-dimethyl phenol are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to achieve a pressure of 180 psi, followed by the addition of carbon dioxide up to a final pressure of 700 psi. The solution is stirred while 0.6 ml pyridine (Cu: amine: DMP 1:44:75) are added through an injector loop with the oxygen/carbon dioxide mixture from the variable volume cell, resulting in a pressure of 3000 psi in the reactor. The high pressure reactor is heated to 40°C, and carbon dioxide is added to achieve a pressure of 4700 psi at 40 °C. After 20 hours stirring at 40°C the carbon dioxide is vented and the product washed with a mixture of 1 % HC1 in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 1.06 g (67%) polyphenylene oxide with an average molecular weight of M_n = 6,140 g/mol and a polydispersity of PDI = 1.63.

Example 8

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.012 g), 0.77 g 2,6-dimethyl phenol, and 1.02 g poly(perfluorooctylacrylate-co-vinylpyridine) with a content of 6.1 wt. % vinylpyridine are added and the reactor is closed. The molar ratio of copper:amine:2,6-dimethyl phenol is 1:22:75. Oxygen is added to a pressure of 240 psi, followed by the addition of carbon dioxide to a pressure of 2300 psi. The reactor is heated to 40 °C and carbon dioxide is added again to a final pressure of 4700 psi at 40°C. After 23 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.14 g (18%) polyphenylene oxide with an average molecular weight of M_n = 2,859 g/mol and a polydispersity of PDI = 3.93.

Example 9

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.52 g 2,6-dimethyl phenol and 1.35 g poly (2- (dimethylamino)ethylacrylate-co-perfluorooctylacrylate) with a content of 13.1 wt. % 2-(dimethylamino)ethylacrylate are added and the reactor is closed. The molar ratio of copper:amine:2,6-dimethyl phenol is 1:22:75. Oxygen is added to a pressure of 330 psi, followed by the addition of carbon dioxide to a pressure of 2500 psi. The reactor is heated to 40 °C, resulting in a pressure of 2800 psi, and then carbon dioxide is added again to a final pressure of 4500 psi at 40 °C. After 18 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1% HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.67 g (44%) polyphenylene oxide with an average molecular weight of M_n = 2,142 g/mol and a polydispersity of PDI = 2.33.

Example 10

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 2.95 g 2,6-dimethyl phenol and 1.37 g poly(2- (dimethylamino)ethylacrylate-co-perfluorooctylacrylate) with a content of 13.1 wt. % 2-(dimethylamino)ethylacrylate are added and the reactor is closed. The molar ratio of copper:amine:2,6-dimethyl phenol is 1:22:150. Oxygen is added to a pressure of 592 psi in the reactor, followed by the addition of carbon dioxide to a pressure of 2000 psi. The reactor is heated to 40 °C, and then carbon dioxide is added again to a final pressure of 5000 psi at 40 °C. After 20 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 1.20 g (40%) polyphenylene oxide with an average molecular weight of M_n = 1,315 g/mol and a polydispersity of PDI = 3.10.

Example 11 A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.66 g 2,6-dimethyl phenol and 1.37 g poly(2- (dimethylamino)ethylacrylate-co-perfluorooctylacrylate) with a content of 13.1 wt. % 2-(dimethylamino)ethylacrylate are added and the reactor is closed. The molar ratio of copper: amine: 2,6-dimethyl phenol is 1:22:75. Oxygen is added to a pressure of 310 psi in the reactor, followed by the addition of carbon dioxide up to a pressure of 4700 psi. After 20 hours stirring at room temperature the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.27 g (16%) polyphenylene oxide with an average molecular weight of M_n = 1,565 g/mol and a polydispersity of PDI =

2.51.

Example 12

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.58 g 2,6-dimethyl phenol, and 0.275 g polyperfluorooctylacrylate are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell, to achieve a pressure of 255 psi, followed by the addition of carbon dioxide to a pressure of 700 psi. The oxygen/carbon dioxide mixture is added to the high pressure reactor to achieve a pressure of 1000 psi. The pressure in the reactor is increased to 1300 psi by the addition of carbon dioxide. The high pressure reactor is heated to 40 °C, resulting in a pressure of 1500 psi and further carbon dioxide is added to achieve a pressure of 2000 psi. The solution is stirred while 0.6 ml pyridine (Cu:amine:DMP 1:44:75) is added through an injector loop to a final pressure of 5000 psi in the reactor. After 20 hours stirring at 40°C the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.78 g (50%) polyphenylene oxide with an average molecular weight of M_n = 8,738 g/mol and a polydispersity of PDI = 1.60.

Example 13 A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.012 g), 0.72 g 2,6-dimethyl phenol, and 0.51 g poly(vinylpyridine- co-perfluorooctylacrylate) with a content of 6.1 wt. % vinylpyridine are added and the reactor is closed. Oxygen is added to a pressure of 270 psi, followed by the addition of carbon dioxide to a pressure of 2000 psi. The reactor is heated to 40 °C and the solution is stirred while 0.075 ml pyridine

(Cu:amine:DMP 1:22:75) is added through an injector loop with carbon dioxide to a final pressure of 5000 psi in the reactor. After 21 hours stirring at 40°C the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.25 g (35%) polyphenylene oxide with an average molecular weight of M_n = 4,224 g/mol and a polydispersity of PDI = 2.40.

Example 14

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.43 g 2,6-dimethyl phenol and 0.397 g poly(2-

(dimethylamino)ethylacrylate-co-perfluorooctylacrylate) with a content of 13.1 wt. % 2(dimethylamino)ethylacrylate are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to achieve a pressure of 180 psi, followed by the addition of carbon dioxide to a final pressure of 1000 psi in the variable volume cell. The oxygen carbon dioxide mixture is added to the high pressure reactor to achieve a pressure of 1300 psi in the reactor. The reactor is heated to 40 °C. The solution is stirred while 0.6 ml pyridine (Cu:amine:DMP 1 :44:75) are added through an injector loop with carbon dioxide to a final pressure of 5000 psi in the reactor. After 20 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of

1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.72 g (51 %) polyphenylene oxide with an average molecular weight of M_n = 11,125 g/mol and a polydispersity of PDI = 1.67.

Example 15

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.72 g 2,6-dimethyl phenol, and 0.40 g poly(2- (dimethylamino)ethylacrylate-co-perfluorooctylacrylate) with a content of 13.1 wt. % 2(dimethylamino)ethylacrylate are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to a pressure of 110 psi, followed by the addition of carbon dioxide to a pressure of 1200 psi in this variable volume cell. The solution is stirred while 0.6 ml pyridine (Cu:amine:DMP 1:44:75) are added through an injector loop with the oxygen/carbon dioxide mixture, followed by the addition of more carbon dioxide to a final pressure of 5000 psi in the reactor. After 20 hours stirring at room temperature the carbon dioxide is vented and the product washed with a mixture of 1% HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.81 g (47%) polyphenylene oxide with an average molecular weight of M_n = 3,464 g/mol and a polydispersity of PDI = 2.09.

Example 16

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.72 g 2,6-dimethyl phenol and 0.281 g polystyrene(4.5k)- b-polyperfluorooctylacrylate(24.5k) are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to achieve a pressure of 200 psi, followed by the addition of carbon dioxide to a final pressure of 795 psi. The oxygen/carbon dioxide mixture is added to the high pressure reactor to achieve a pressure of 1173 psi in the reactor. The reactor is heated to 40°C. The solution is stirred while 0.6 ml pyridine (Cu: amine: DMP 1:44:75) are added through an injector loop with carbon dioxide to a final pressure of 5000 psi in the reactor. After 20 hours stirring at 40 °C the carbon dioxide is vented and the product washed with 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 1.28 g (74%) polyphenylene oxide with an average molecular weight of M_n = 17,150 g/mol and a polydispersity of PDI = 5.77.

Example 17

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.54 g 2,6-dimethyl phenol, 0.248 g polystyrene(4.5k)-b- polyperfluorooctylacrylate(24.5k) and 0.1 ml toluene are added and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to achieve a pressure of 200 psi, followed by the addition of carbon dioxide to a pressure of 780 psi. The oxygen/carbon dioxide mixture is added to the high pressure reactor and the reactor is heated to 40 °C. The solution is stirred while 0.6 ml pyridine (Cu:amine:DMP 1:44:75) is added through an injector loop with carbon dioxide. The final pressure in the reactor is 5000 psi. After 20 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1% HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.72 g (47%) polyphenylene oxide with an average molecular weight of M_n = 10,714 g/mol and a polydispersity of PDI = 1.85.

Example 18

A 10 ml high pressure reactor is purged with argon. Cupric bromide (0.024 g), 1.69 g 2,6-dimethyl phenol and 0.035 g polystyrene(4.5k)- b-polyperfluorooctylacrylate(24.5k) are added, and the reactor is closed. Oxygen is added to a 30 ml variable volume cell to achieve a pressure of 188 psi, followed by the addition of carbon dioxide to a pressure of 710 psi. The oxygen/carbon dioxide mixture is added to the high pressure reactor to achieve a pressure of 1161 psi in the reactor. The reactor is heated to 40 °C and more carbon dioxide is added to a pressure of 2300 psi at 40 °C. The solution is stirred while 0.6 ml pyridine (Cu:amine:DMP 1:44:75) is added through an injector loop with carbon dioxide. The final pressure in the reactor is 5000 psi. After 20 hours stirring at 40 °C the carbon dioxide is vented and the product washed with a mixture of 1 % HCl in methanol. The product is filtered and precipitated from toluene into methanol. The reaction yields 0.59 g (35%) polyphenylene oxide with an average weight of M_n = 5760 g/mol and a polydispersity of PDI = 2.35.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

That Which Is Claimed Is:

1. A process for making poly(phenylene oxide) polymers comprising:

(a) providing a polymerization medium comprising carbon dioxide; (b) contacting a phenol monomer with a catalyst capable of catalyzing the polymerization of said phenol monomer, in said polymerization medium; and

(c) polymerizing said phenol monomer in said polymerization medium.

2. The process according to Claim 1, wherein said phenol monomer has the formula (I)

wherein R-., R₂, R,, and R₅ are independently selected from the group consisting of H, halogen, alkyl, substimted alkyl, alkoxy, phenyl, phenoxy, carboxy, alkyl substituted carboxy, and perfluoroalkyl; and R₃ is selected from the group consisting of H and halogen.

3. The process according to Claim 1, wherein said phenol monomer is selected from the group consisting of 2,6-dimethyl phenol.

4. The process according to Claim 1, wherein said polymerization medium comprises liquid carbon dioxide.

5. The process according to Claim 1, wherein said polymerization medium comprises supercritical carbon dioxide.

6. The process according to Claim 1, wherein said polymerization medium comprises gaseous carbon dioxide.

7. The process according to Claim 1 , wherein said catalyst is a multi-component system comprising (i) a transition metal salt, (ii) an amine, and (Hi) oxygen

8. The process according to Claim 1, wherein said catalyst is a multi-component system comprising ( ) a copper salt selected from the group consisting of copper (I) bromide and copper (I) chloride , (ii) an amine selected from the group consisting of polymeric amines, dibutyl amine, and pyridine, and (Hi) oxygen.

9. The process according to Claim 1, wherein said catalyst is a multi-component system comprising ( ) copper (I) bromide, (ii) dibutylamine, and (Hi) oxygen.

10. The process according to Claim 1, wherein said catalyst is a multi-component system comprising (0 copper (I) bromide, (ii) pyridine, and (Hi) oxygen.

11. The process according to Claim 1, wherein said catalyst is a multi-component system comprising ( ) copper (I) bromide, (ii) poly (2-

(dimethylamino)ethylacrylate-co-perfluorooctylacrylate), and (Hi) oxygen.

12. The process according to Claim 1, further comprising contacting a comonomer with said phenol monomer, said catalyst, and said polymerization medium, and said polymerizing step comprises copolymerizing said phenol monomer with said comonomer.

13. The process according to Claim 12, wherein said comonomer is selected from the group consisting of 2,6-dimethyl phenol, 2,6- diethyl phenol, 2,6-dibutyl phenols, 2,6-dilauryl phenol, 2,6-dipropyl phenols, 2,6-diphenyl phenol, 2-methyl-6-ethyl phenol, 2-methyl-6-propargyl phenol, 2- methyl-6-cyclohexyl phenol, 2-methyl-6-benzyl phenol, 2-methyl-6-tolyl phenol,

2-methyl-6-methoxy phenol, 2-ethyl-6-phenylethyl phenol, 2,6-dimethoxy phenol, 2,3,6-trimethyl phenol, 2,3,5,6-tetramethyl phenol, 2,6-diethoxy phenol, 2-methoxy-6-ethoxy-phenol, 2-ethyl-6-stearyloxy phenol, 2,6-di- (chlorophenoxy) phenols, 2-6-dimethyl-3-chloro phenol, 2-methyl-6-bromo phenol, 2-methyl-4-chloro-6-bromo phenol, 2,3,5-trimethyl-6-chloro phenol,

2,6-dimethyl-4-chloro phenol, 2,6-dimethyl-3-chloro-5-bromophenol, 2.6-di- (chloroethyl) phenol, 2-methyl-6-isobutyl phenol, 2-methyl-6-phenylphenol, 2,6- dibenzyl phenol, 2,6-ditolyl phenol, 2.6-di-(chloropropyl) phenol, and 2,6-di- (2' ,4'-dichlorophenol)-3-allyl phenol.

14. The process according to Claim 1, wherein said polymerization medium further comprises a cosolvent.

15. The process according to Claim 1, wherein said process is carried out in the presence of a surfactant.

16. The process according to Claim 15, wherein said surfactant contains a carbon dioxide-soluble segment.

17. The process according to Claim 15, wherein said surfactant is selected from the group consisting of fluorinated polymers, fluorinated copolymers, siloxane polymers, and siloxane copolymers.

18. The process according to Claim 1, further comprising the steps of separating said poly(phenylene oxide) polymer from said polymerization medium, and collecting said poly(phenylene oxide) polymer.

19. The process according to Claim 18, wherein said step of separating said poly(phenylene oxide) polymer comprises venting said polymerization medium to the atmosphere.

20. The process according to Claim 18, further comprising the step of washing the polymer with a wash fluid comprising carbon dioxide, prior to said step of collecting said poly(phenylene oxide) polymer.

21. A poly(phenylene oxide) polymer prepared according to the process of claim 1.

22. A polymerization reaction mixture useful for carrying out the polymerization of a phenol monomer comprising (a) a phenol monomer, (b) a catalyst capable of catalyzing the polymerization of a phenol monomer, and (c) a polymerization medium comprising carbon dioxide.

23. A mixture produced by the polymerization of a phenol monomer consisting essentially of (a) a poly(phenylene oxide) polymer, and (b) a polymerization medium comprising carbon dioxide.