DEPOLYMERIZED POLY(CARBONATE)

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. Provisional Application No. 62/863,355 filed on June 19, 2019, the contents of which is incorporated by reference herein in its entirety.

BACKGROUND

[0001] Poly (carbonate) s are useful in the manufacture of articles and components for a wide range of applications, from automotive parts to electronic appliances. However, poly (carbonate) s are not readily biodegradable and can present a significant bulk waste disposal problem. Accordingly, efforts have been made to recover valuable resources from

poly(carbonate) wastes.

[0002] Poly (carbonate) s can be depolymerized to generate the corresponding small molecule constituents, for example 4,4’-isopropylidenediphenol (also referred to as bisphenol A) and other byproducts. There remains a continuing need for an improved process for

depolymerizing poly(carbonate)s where bisphenol A can be appropriately purified for further use. It would be a further advantage to provide a process which minimizes the formation of byproducts to assist in facile purification of the bisphenol A. It would be a further advantage to conduct the depolymerization under mild conditions.

SUMMARY

[0003] A process for depolymerization of poly(carbonate) comprises combining a poly(carbonate) comprising repeating units derived from bisphenol A; bisphenol A; water; and a base; under conditions effective to form a single liquid phase and to depolymerize the

poly (carbonate).

[0004] A process for isolation of bisphenol A from a depolymerized poly(carbonate) comprises depolymerizing a poly (carbonate); isolating bisphenol A; and crystallizing the isolated bisphenol A with a crystallization solvent to provide a purified bisphenol A; wherein the purified bisphenol A is 4,4’-isopropylidenediphenol having a purity of greater than 99.8%.

[0005] A bisphenol A obtained the process is also described.

[0006] A thermoplastic polymer comprises repeating units derived from the bisphenol A. [0007] A method of making a poly(etherimide) comprises isolating bisphenol A from depolymerization of a poly(carbonate) according to the process described herein; forming an aromatic bis(ether anhydride) from the isolated bisphenol A; and reacting the aromatic bis(ether anhydride) with an organic diamine to form the poly(etherimide).

[0008] The above described and other features are exemplified by the following detailed description.

DETAILED DESCRIPTION

[0009] Described herein is a process for depolymerization of a poly(carbonate) which can advantageously provide bisphenol A having a purity suitable for use in making new thermoplastic materials. The process provided by the present disclosure is advantageously a base-catalyzed hydrolysis which has the advantage of depolymerizing the poly(carbonate) to bisphenol A and carbon dioxide, which is easily removed. This is in contrast to other processes such as ammonolysis (which produces a urea byproduct), alcoholysis (which produces dialkyl carbonates), and phenolysis (which produces diaryl carbonates). The process of the present disclosure can advantageously provide completely depolymerized poly(carbonate) in short times, and using mild conditions. In a further advantageous feature, the bisphenol A recovered from the depolymerization can be purified according to the process described herein to a purity of greater than 99.8%, with low color, and in good yield. Thus, the bisphenol A isolated from the depolymerization process described herein can find use in providing new thermoplastic materials.

[0010] Accordingly, an aspect of the present disclosure is a process for depolymerization of a poly (carbonate).“Poly(carbonate)” as used herein means a homopolymer or copolymer having repeating structural carbonate units of the formula (1)

O

- R ¹ — O— C— O - (1)

wherein at least 60 percent of the total number of R ¹ groups are aromatic, or each R ¹ contains at least one C6-30 aromatic group. Each occurrence of R ¹ can be the same or different.

Poly (carbonate) s and their methods of manufacture are known in the art, being described, for example, in WO 2013/175448 Al, US 2014/0295363, and WO 2014/072923. Poly(carbonate)s are generally manufactured from bisphenol compounds such as 2,2-bis(4-hydroxyphenyl) propane (“bisphenol-A” or“BPA”), 3,3-bis(4-hydroxyphenyl) phthalimidine, l,l-bis(4- hydroxy-3-methylphenyl)cyclohexane, or l,l-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (isophorone), or a combination thereof can also be used. [0011] The poly(carbonate) of the present disclosure comprises repeating units derived from bisphenol A. For example, the poly(carbonate) is a homopolymer derived from bisphenol A; a copolymer derived from bisphenol A and another bisphenol or dihydroxy aromatic compound such as resorcinol; or a copolymer derived from bisphenol A and optionally another bisphenol or dihydroxy aromatic compound, and further comprising non-carbonate units, for example aromatic ester units such as resorcinol terephthalate or isophthalate, aromatic-aliphatic ester units based on C6-20 aliphatic diacids, polysiloxane units such as polydimethylsiloxane units, or a combination thereof. Some illustrative examples of other dihydroxy compounds that can be used in combination with bisphenol A are described, for example, in WO 2013/175448 Al, US 2014/0295363, and WO 2014/072923, incorporated herein by reference in their entirety.

[0012] In a specific aspect, the poly (carbonate) is a linear homopolymer containing bisphenol A carbonate units (BPA-PC).

[0013] The poly(carbonate)s can have an intrinsic viscosity, as determined in chloroform at 25°C, of 0.3 to 1.5 deciliters per gram (dl/gm), preferably 0.45 to 1.0 dl/gm. The

poly (carbonate) s can have a weight average molecular weight (Mw) of 10,000 to 200,000 grams per mole (Daltons), preferably 17,000 to 35,000 Daltons, as measured by gel permeation chromatography (GPC), using a crosslinked styrene-divinylbenzene column and calibrated to bisphenol A homopoly (carbonate) references. GPC samples are prepared at a concentration of 1 milligram per milliliter, and are eluted at a flow rate of 1.5 milliliter per minute.

[0014] Poly (carbonate) s useful for the process of the present disclosure can include virgin poly(carbonate)s, post-consumer recycled poly(carbonate)s, post-industrial recycled poly(carbonate)s, and combinations thereof. In an aspect, the poly(carbonate) can be obtained from multiple sources, and can therefore comprise a combination of poly(carbonate)s having slight variances in structure or compositions, for example having different comonomers or end groups or additives. For example, poly(carbonate)s can be produced using various end-capping agents (also referred to as a chain stopper agent or chain terminating agent) which can be included during polymerization to provide particular end groups, for example monocyclic phenols such as phenol, p-cyanophenol, and Ci-22 alkyl-substituted phenols such as p-cumyl- phenol, resorcinol monobenzoate, and p-and m-tertiary-butyl phenol, monoethers of diphenols, such as p-methoxyphenol, monoesters of diphenols such as resorcinol monobenzoate, and functionalized chlorides of aliphatic monocarboxylic acids such as acryloyl chloride and methacryoyl chloride,. In an aspect, the poly(carbonate) can have an end group derived from at least one of phenol, p-cumylphenol, p-t-butylphenol, and p-t-octylphenol. Combinations of different end groups can be used. Thus the poly(carbonate) used in the present process can be a combination of bisphenol A-containing poly (carbonate) s having different end groups.

[0015] It is also understood that when a post-consumer recycled poly(carbonate) or post industrial recycled poly(carbonate) are used, the poly(carbonate) stream can optionally contain one or more additives or additional thermoplastic polymers different from the poly (carbonate).

[0016] The process of the present disclosure comprises combining the poly(carbonate) comprising repeating units derived from bisphenol A, bisphenol A, water, a base, and optionally an organic solvent, under conditions effective to form a single liquid phase and depolymerize the poly (carbonate).

[0017] The organic solvent, when present, can generally be any organic solvent that can swell the poly(carbonate) to assist in depolymerization, and has a boiling point high enough such that excessive pressure builds up can be avoided at elevated temperatures during the

depolymerization. Further, the organic solvent can preferably allow for crystallization of the crude bisphenol A that results from the depolymerization step without requiring a solvent exchange. In an aspect, the organic solvent can comprise toluene, chlorobenzene, xylene, and the like, or a combination thereof. In a specific aspect, the organic solvent comprises toluene.

[0018] The base can comprise an alkali metal carbonate, an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium hydroxide, a phosphonium hydroxide, or a combination thereof. In an aspect, the base can be an alkali metal carbonate, for example sodium carbonate.

[0019] In an aspect, the poly(carbonate) can be present in an amount of 10 to 30 weight percent; the bisphenol A can be present in an amount of 1 to 65 weight percent; the organic solvent can be present in an amount of 5 to 65 weight percent; and the water can be present in an amount of 5 to 35 weight percent; wherein weight percent of each component is based on the total weight of the poly (carbonate), the organic solvent, water, bisphenol A, and the base.

[0020] The depolymerizing can be conducted at a temperature of 110 to 130°C, preferably 115 to 125°C, and a pressure of 10 to 75 psig, for example 15 to 50 psig, for example 20 to 40 psig. The depolymerization can be conducted for a time effective to depolymerize the poly (carbonate). The degree of depolymerization can be monitored, for example, by ultra performance liquid chromatography (UPLC), as further described in the working examples below. For example, the depolymerizing can be for a time of 24 hours or less, preferably 16 hours or less, more preferably 10 hours or less, even more preferably 6 hours or less. Within these ranges, the depolymerizing can be for a time of 1 to 24 hours, or 1 to 18 hours, or 1 to 10 hours, or 1 to 6 hours. [0021] The process of the present disclosure can optionally further comprise isolating bisphenol A, and crystallizing the isolated bisphenol A with a crystallization solvent to provide a purified bisphenol A. Following addition of the crystallization solvent, the resulting mixture can be heated to a suitable temperature to effect dissolution of the bisphenol A, and the solution can then be cooled. Upon cooling, the bisphenol A can be crystallized from the crystallization solution, and can further be isolated, for example by filtration.

[0022] The crystallization solvent can comprise, for example, a mixture of toluene, isopropanol, and optionally, acetic acid. Crystallization of the bisphenol A from the

depolymerization reaction mixture is further described in the working examples below.

[0023] Another aspect of the present disclosure is a process for isolation of bisphenol A from a depolymerized poly (carbonate). The process comprises depolymerizing a

poly(carbonate) according to the process described herein; isolating bisphenol A; and crystallizing the isolated bisphenol A with a crystallization solvent to provide a purified bisphenol A; wherein the purified bisphenol A is 4,4’-isopropylidenediphenol having a purity of greater than 99.8%.

[0024] Advantageously, the isolated bisphenol A can have a high purity. For example, the isolated bisphenol A can have a purity of greater than 99.8%. In an aspect, the isolated bisphenol A can be 4,4’-isopropylidenediphenol having a purity of greater than 99.8%. The process described herein can effectively remove many types of additives (e.g., heat stabilizers, mold release agents, and the like), that can be present, in particular when the poly(carbonate) stream is at least partially derived from a post-consumer recycled poly (carbonate). The isolated bisphenol A can also advantageously comprise less than 0.2 weight percent of a monophenol, for example a monophenol typically used as an end-capping agent, as described above. In particular, the isolated bisphenol A can comprise less than 0.2 weight percent of a monophenol comprising p-cumylphenol, t-butylphenol, p-t-octylphenol, or a combination thereof. This represents an important advantage of the present process because the minimization of monophenol compounds present in the bisphenol A can allow for production of high molecular weight polymers when the bisphenol A is used for subsequent polymerization reactions. Stated another way, the presence of excess monophenol compounds in the bisphenol A can undesirably limit the molecular weight of the polymer.

[0025] Thus, another aspect of the present disclosure is a thermoplastic polymer comprising repeating units derived from the bisphenol A made by the process described herein. The thermoplastic polymer can be any polymer having repeat units derived from bisphenol A, and can include, for example, poly(carbonate)s, poly(etherimide)s, polysulfones, epoxies, and the like. Preferably, the thermoplastic polymer can be a poly(carbonate) or a poly(etherimide), more preferably a poly(etherimide).

[0026] In an aspect, the bisphenol A made from the process described herein can be used to provide a poly(carbonate). The poly(carbonate) can be a homopolymer or copolymer having the repeating structural carbonate units according to formula (1) described above. At least a portion (e.g., at least 10%) of the R ¹ groups of formula (1) are derived from the bisphenol A obtained by the method described herein. The remainder of the R ¹ groups can be derived from a dihydroxy compound such as an aromatic dihydroxy compound of formula (2) or a bisphenol of formula (3).

In formula (2), each R ^h is independently a halogen atom, for example bromine, a Ci-io hydrocarbyl group such as a CMO alkyl, a halogen-substituted Ci-io alkyl, a C6-10 aryl, or a halogen-substituted C ₆ -io aryl, and n is 0 to 4.

[0027] In formula (3), R ^a and R ^b are each independently a halogen, Ci-12 alkoxy, or Ci-12 alkyl, and p and q are each independently integers of 0 to 4, such that when p or q is less than 4, the valence of each carbon of the ring is filled by hydrogen. In an aspect, p and q is each 0, or p and q is each 1, and R ^a and R ^b are each a C1-3 alkyl group, preferably methyl, disposed meta to the hydroxy group on each arylene group. X ^a is a bridging group connecting the two hydroxy- substituted aromatic groups, where the bridging group and the hydroxy substituent of each Ce arylene group are disposed ortho, meta, or para (preferably para) to each other on the Ce arylene group, for example, a single bond, -0-, -S-, -S(O)-, -S(0) ₂ -, -C(O)-, or a C _MS organic group, which can be cyclic or acyclic, aromatic or non-aromatic, and can further comprise heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. For example, X ^a can be a substituted or unsubstituted C3-18 cycloalky lidene; a Ci-25 alkylidene of the formula -C(R ^c )(R ^d ) - wherein R ^c and R ^d are each independently hydrogen, Ci-12 alkyl, Ci-12 cycloalkyl, C7-12 arylalkyl, Ci-12 heteroalkyl, or cyclic C7-12 heteroarylalkyl; or a group of the formula -C(=R ^e )- wherein R ^e is a divalent Ci-12 hydrocarbon group. Bisphenols of formula (3) can include bisphenol A that has not been recovered from a depolymerization process.

[0028] Examples of bisphenol compounds include 4,4'-dihydroxybiphenyl, 1,6- dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4- hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-l-naphthylmethane, l,2-bis(4- hydroxyphenyl)ethane, l,l-bis(4-hydroxyphenyl)-l-phenylethane, 2-(4-hydroxyphenyl)-2-(3- hydroxyphenyl)propane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3- bromophenyl)propane, 1,1 -bis (hydroxyphenyl)cyclopentane, l,l-bis(4- hydroxyphenyl)cyclohexane, 1 , 1 -bis(4-hydroxyphenyl)isobutene, 1 , 1 -bis(4- hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4- hydroxyphenyl)adamantane, alpha, alpha' -bis(4-hydroxyphenyl)toluene, bis(4- hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4- hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4- hydroxyphenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4- hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4- hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4- hydroxyphenyl)hexafluoropropane, 1 , 1 -dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 1,1- dibromo-2,2-bis(4-hydroxyphenyl)ethylene, l,l-dichloro-2,2-bis(5-phenoxy-4- hydroxyphenyl)ethylene, 4,4'-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,

1.6-bis(4-hydroxyphenyl)-l,6-hexanedione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4- hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl) sulfoxide, bis(4- hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorene, 2,7-dihydroxypyrene, 6,6'- dihydroxy-3,3,3',3'- tetramethylspiro(bis)indane ("spirobiindane bisphenol"), 3,3-bis(4- hydroxyphenyl)phthalimide, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene, 2,7- dihydroxyphenoxathin, 2,7-dihydroxy-9, 10-dimethylphenazine, 3,6-dihydroxydibenzofuran,

3.6-dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole; resorcinol, substituted resorcinol compounds such as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromo resorcinol, or the like; catechol; hydroquinone; substituted hydroquinones such as 2-methyl hydroquinone, 2-ethyl hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone,

2.3.5.6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluoro hydroquinone, 2,3,5,6-tetrabromo hydroquinone, or the like.

[0029] Specific dihydroxy compounds include resorcinol, 2,2-bis(4-hydroxyphenyl) propane (“bisphenol A” or“BPA”), 3,3-bis(4-hydroxyphenyl) phthalimidine, 2-phenyl-3,3’- bis(4-hydroxyphenyl) phthalimidine (also known as N-phenyl phenolphthalein bisphenol, “PPPBP”, or 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-l-one), l,l-bis(4-hydroxy-3- methylphenyl)cyclohexane, and 1 , 1 -bis(4-hydroxyphenyl)-3 ,3 ,5-trimethylcyclohexane

(isophorone bisphenol). [0030] The poly(carbonate)s prepared from the bisphenol A obtained by the method described herein can also include copolymers comprising carbonate units and ester units (“poly(ester-carbonate)s”). Poly (ester-carbonate) s further contain, in addition to recurring carbonate chain units of formula (1), repeating ester units of formula (4)

wherein J is a divalent group derived from a dihydroxy compound (which includes a reactive derivative thereof), and can be, for example, a CHO alkylene, a C6-20 cycloalkylene, a C5-20 arylene, or a polyoxyalkylene group in which the alkylene groups contain 2 to 6 carbon atoms, preferably, 2, 3, or 4 carbon atoms; and T is a divalent group derived from a dicarboxylic acid (which includes a reactive derivative thereof), and can be, for example, a C i-20 alkylene, a C5-20 cycloalkylene, or a C6-20 arylene. Copolyesters containing a combination of different T or J groups can be used. The polyester units can be branched or linear.

[0031] Dihydroxy compounds can be used in addition to the bisphenol A obtained by the process of the present disclosure and can include aromatic dihydroxy compounds of formula (2) (e.g., resorcinol), bisphenols of formula (3) (e.g., bisphenol A), a Ci-s aliphatic diol such as ethane diol, n-propane diol, i-propane diol, 1,4-butane diol, 1,4-cyclohexane diol, 1,4- hydroxymethylcyclohexane, or a combination thereof dihydroxy compounds. Aliphatic dicarboxylic acids that can be used include C5-20 aliphatic dicarboxylic acids (which includes the terminal carboxyl groups), preferably linear Cs-i2 aliphatic dicarboxylic acid such as decanedioic acid (sebacic acid); and alpha, omega-Ci2 dicarboxylic acids such as dodecanedioic acid

(DDDA). Aromatic dicarboxylic acids that can be used include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, or a combination thereof acids. A combination of isophthalic acid and terephthalic acid wherein the weight ratio of isophthalic acid to terephthalic acid is 91:9 to 2:98 can be used.

[0032] Specific ester units include ethylene terephthalate units, n-proplyene terephthalate units, n-butylene terephthalate units, ester units derived from isophthalic acid, terephthalic acid, and resorcinol (ITR ester units), and ester units derived from sebacic acid and bisphenol A. The molar ratio of ester units to carbonate units in the poly (ester-carbonate) s can vary broadly, for example 1:99 to 99:1, preferably, 10:90 to 90:10, more preferably, 25:75 to 75:25, or from 2:98 to 15:85. In some aspects the molar ratio of ester units to carbonate units in the poly(ester- carbonate)s can vary from 1:99 to 30: 70, preferably 2:98 to 25:75, more preferably 3:97 to 20:80, or from 5:95 to 15:85. [0033] In another aspect, the poly(carbonate) is a poly(carbonate-siloxane) copolymer comprising bisphenol A carbonate units and siloxane units, for example blocks containing 5 to 200 dimethylsiloxane units.

[0034] Other specific poly(carbonate)s that can be prepared from the bisphenol A of the present disclosure can include poly(aromatic ester-carbonate) s comprising bisphenol A carbonate units and isophthalate-terephthalate-bisphenol A ester units, also commonly referred to as poly (carbonate-ester) s (PCE) or poly(phthalate-carbonate)s (PPC), depending on the relative ratio of carbonate units and ester units. Another specific poly (ester-carbonate) comprises resorcinol isophthalate and terephthalate units and bisphenol A carbonate units.

[0035] In an aspect, the bisphenol A obtained by the process of the present disclosure can be particularly useful for the preparation of poly(etherimide)s. Poly(etherimide)s comprise more than 1, for example 2 to 1000, or 5 to 500, or 10 to 100 structural units of formula (5)

wherein each R is independently the same or different, and is a substituted or unsubstituted divalent organic group, such as a substituted or unsubstituted C6-20 aromatic hydrocarbon group, a substituted or unsubstituted straight or branched chain C4-20 alkylene group, a substituted or unsubstituted C3-8 cycloalkylene group, in particular a halogenated derivative of any of the foregoing. In an aspect R is divalent group of one or more of the following formulas (6)

wherein Q ¹ is -0-, -S-, -C(O)-, -SO2-, -SO-, -P(R ^a )(=0)- wherein R ^a is a Ci-s alkyl or C6-12 aryl, - C _y th _y - wherein y is an integer from 1 to 5 or a halogenated derivative thereof (which includes perfluoroalkylene groups), or -(O _ό Hio) _z - wherein z is an integer from 1 to 4. In an aspect R is m- phenylene, p-phenylene, or a diarylene sulfone, in particular bis(4,4’-phenylene)sulfone, bis(3,4’-phenylene)sulfone, bis(3,3’-phenylene)sulfone, or a combination comprising at least one of the foregoing. In an aspect, at least 10 mole percent or at least 50 mole percent of the R groups contain sulfone groups, and in an aspect no R groups contain sulfone groups.

[0036] Further in formula (5), T is a group derived from the bisphenol A obtained by the process of the present disclosure. Optionally, the poly(etherimide) can further comprise additional repeating units where T is a group of the formula -O-Z-O- wherein the divalent bonds of the -O-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions, and Z is an aromatic C6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 Ci-s alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing, provided that the valence of Z is not exceeded. Exemplary groups Z include groups of formula (7)

wherein R ^a and R ^b are each independently the same or different, and are a halogen atom or a monovalent Ci- ₆ alkyl group, for example; p and q are each independently integers of 0 to 4; c is 0 to 4; and X ^a is a bridging group connecting the hydroxy-substituted aromatic groups, where the bridging group and the hydroxy substituent of each Ce arylene group are disposed ortho, meta, or para (specifically para) to each other on the Ce arylene group. The bridging group X ^a can be a single bond, -0-, -S-, -S(O)-, -S(0) ₂ -, -C(O)-, or a C _MS organic bridging group. The Ci-18 organic bridging group can be cyclic or acyclic, aromatic or non-aromatic, and can further comprise heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. The Ci-18 organic group can be disposed such that the Ce arylene groups connected thereto are each connected to a common alkylidene carbon or to different carbons of the Ci-is organic bridging group. A specific example of a group Z is a divalent group of formula (7a)

wherein Q is -0-, -S-, -C(O)-, -SO2-, -SO-, -P(R ^a )(=0)- wherein R ^a is a Ci-s alkyl or Ce-12 aryl, or -C _y H2 _y - wherein y is an integer from 1 to 5 or a halogenated derivative thereof (including a perfluoroalkylene group). In an aspect Z is a derived from bisphenol A, such that Q in formula (7a) is 2,2-isopropylidene.

[0037] In an aspect in formula (5), R is m-phenylene, p-phenylene, or a combination comprising at least one of the foregoing, and T is a divalent group derived from the bisphenol A of the present disclosure. Alternatively, the poly(etherimide) can be a copolymer comprising additional structural poly(etherimide) units of formula (5) wherein at least 50 mole percent (mol%) of the R groups are bis(4,4’-phenylene)sulfone, bis(3,4’-phenylene)sulfone, bis(3,3’- phenylene)sulfone, or a combination comprising at least one of the foregoing and the remaining R groups are p-phenylene, m-phenylene or a combination comprising at least one of the foregoing; and T is a divalent group derived from the bisphenol A of the present disclosure.

[0038] In an aspect, the poly(etherimide) is a copolymer that optionally comprises additional structural imide units that are not poly(etherimide) units, for example imide units of formula (8)

wherein R is as described in formula (5) and each V is the same or different, and is a substituted or unsubstituted C6-20 aromatic hydrocarbon group, for example a tetravalent linker of the formulas

wherein W is a single bond, -O-, -S-, -C(O)-, -SO2-, -SO-, a C1-18 hydrocarbylene group, - P(R ^a )(=0)- wherein R ^a is a Ci-s alkyl or C6-12 aryl, or -C _y tb _y - wherein y is an integer from 1 to 5 or a halogenated derivative thereof (which includes perfluoroalkylene groups). These additional structural imide units preferably comprise less than 20 mol% of the total number of units, and more preferably can be present in amounts of 0 to 10 mol% of the total number of units, or 0 to 5 mol% of the total number of units, or 0 to 2 mol% of the total number of units. In an aspect, no additional imide units are present in the poly(etherimide).

[0039] The poly(etherimide) can also be a poly(siloxane-etherimide) copolymer comprising poly(etherimide) units of formula (5) and siloxane blocks of formula (9)

wherein E has an average value of 2 to 100, 2 to 31, 5 to 75, 5 to 60, 5 to 15, or 15 to 40, each R’ is independently a Ci-13 monovalent hydrocarbyl group. For example, each R’ can

independently be a Ci-13 alkyl group, Ci-13 alkoxy group, C2-13 alkenyl group, C2-13 alkenyloxy group, C3-6 cycloalkyl group, C3-6 cycloalkoxy group, C6-14 aryl group, C6-10 aryloxy group, C7-13 arylalkylene group, C7-13 arylalkylenoxy group, C7-13 alkylarylene group, or C7-13 alkylaryleneoxy group. The foregoing groups can be fully or partially halogenated with fluorine, chlorine, bromine, or iodine, or a combination comprising at least one of the foregoing. In an aspect no bromine or chlorine is present, and in an aspect no halogens are present.

Combinations of the foregoing R groups can be used in the same copolymer. In an aspect, the polysiloxane blocks comprises R’ groups that have minimal hydrocarbon content. In an aspect, an R’ group with a minimal hydrocarbon content is a methyl group.

[0040] The poly(etherimide) can be prepared by any of the methods known to those skilled in the art, including the reaction of an aromatic bis(ether anhydride) of formula (10) or a chemical equivalent thereof, with an organic diamine of formula (11)

wherein T and R are defined as described above. Copolymers of the poly(etherimide)s can be manufactured using a combination of an aromatic bis(ether anhydride) of formula (10) and an additional bis(anhydride) that is not a bis(ether anhydride), for example pyromellitic dianhydride or bis(3,4-dicarboxyphenyl) sulfone dianhydride. At least a portion of the aromatic bis(ether anhydride) of formula (10) can be formed from the isolated bisphenol A of the present disclosure according to methods that are generally known. A combination of different aromatic bis(ether anhydride)s can be used, for example an aromatic bis(ether anhydride) derived from the isolated bisphenol A of the present disclosure and one or more aromatic bis(ether anhydride)s that are derived from bisphenol A made by a different process, are derived from a different dihydroxy aromatic compound, or both.

[0041] Examples of organic diamines include 1,4-butane diamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- decanediamine, 1,12-dodecanediamine, 1,18-octadecanediamine, 3- methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 4- methylnonamethylenediamine, 5-methylnonamethylenediamine, 2,5- dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 2, 2- dimethylpropylenediamine, N-methyl-bis (3-aminopropyl) amine, 3- methoxyhexamethylenediamine, l,2-bis(3-aminopropoxy) ethane, bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine, bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p- phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine, p- xylylenediamine, 2-methyl-4, 6-diethyl- 1 ,3-phenylene-diamine, 5-methyl-4, 6-diethyl- 1,3- phenylene-diamine, benzidine, 3,3’-dimethylbenzidine, 3,3’-dimethoxybenzidine, 1,5- diaminonaphthalene, bis(4-aminophenyl) methane, bis(2-chloro-4-amino-3,5-diethylphenyl) methane, bis(4-aminophenyl) propane, 2,4-bis(p-amino-t-butyl) toluene, bis(p-amino-t- butylphenyl) ether, bis(p-methyl-o-aminophenyl) benzene, bis(p-methyl-o-aminopentyl) benzene, l,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide, bis-(4-aminophenyl) sulfone (also known as 4,4'-diaminodiphenyl sulfone (DDS)), and bis(4-aminophenyl) ether.

Any regioisomer of the foregoing compounds can be used. C alkylated or poly(Ci-4)alkylated derivatives of any of the foregoing can be used, for example a polymethylated 1,6- hexanediamine. Combinations of these compounds can also be used. In an aspect the organic diamine is m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 3,4'- diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, or a combination comprising at least one of the foregoing.

[0042] The poly(etherimide)s can have a melt index of 0.1 to 10 grams per minute (g/min), as measured by American Society for Testing Materials (ASTM) D1238 at 340 to 370°C, using a 6.7 kilogram (kg) weight. In an aspect, the poly(etherimide) has a weight average molecular weight (Mw) of 1,000 to 150,000 grams/mole (Daltons), as measured by gel permeation chromatography, using polystyrene standards. In an aspect the poly(etherimide) has an Mw of 10,000 to 80,000 Daltons. Such poly(etherimide)s typically have an intrinsic viscosity greater than 0.2 deciliters per gram (dl/g), or, more specifically, 0.35 to 0.7 dl/g as measured in m-cresol at 25 °C.

[0043] Thus the process of the present disclosure advantageously combines

poly(carbonate) depolymerization, bisphenol A purification, and solvent recovery and recycle to provide an improved process for the isolation of bisphenol A from depolymerization of poly (carbonate). Careful selection of the bisphenol A purification employed has allowed for the bisphenol A to be obtained with high purity, making it desirable for subsequent use of the preparation of various thermoplastic polymers such as poly(carbonate) and poly(etherimide). Therefore a significant improvement is provided by the process of the present disclosure.

[0044] This disclosure is further illustrated by the following examples, which are non limiting.

EXAMPLES

Poly(carbonate) Depolymerization [0045] Each of the following examples employed the same general procedure.

Poly(carbonate) pellets (obtained as LEXAN 100 from SABIC), bisphenol A (BPA), toluene, water, and sodium carbonate (NaiCCE) were added to a tube reactor equipped with a stir bar. The amounts of each component are provided in Table 1 below, where the amount of each component is provided in grams. The reaction tubes were sealed and placed into an oil bath that was heated to 120°C. Mixing was accomplished with a magnetic stir bar, and the stir rate for each example was 535 rpm.

Table 1

“*” Denotes a Comparative Example

Table 1 (continued)

“*” Denotes a Comparative Example

[0046] After 6 hours, each reaction mixture was analyzed by Fourier Transform Infrared (FTIR) spectroscopy to determine the extent of the polymerization. Example 3, 4, 11 and 12 were each observed to have been completely depolymerized within 6 hours, with no pellets remaining suspended in the reaction mixture, and no detectable carbonate stretch by FTIR. In contrast, Example 2, 5-10, 13-15 and 17-25 either still contained undissolved PC pellets in the reaction mixture after 6 hours, or FTIR analysis indicated a measurable carbonate stretch. So these Examples will obtain complete depolymerization at longer times (i.e., greater than 6 hours).

[0047] The poly(carbonate) depolymerization was also scaled up, as described below. [0048] To a 600 milliliter Parr reactor equipped with magnetic stir bar, glass liner, and internal thermocouple was charged 25 grams of poly(carbonate) pellets (obtained as LEXAN 100 from SABIC), 10 grams of deionized water, 30.42 grams of toluene, 45.01 grams of BPA, and 0.51 grams of sodium carbonate. The reactor was then placed in a heating mantle and sealed. The reactor was heated to 125 °C overnight to ensure complete depolymerization. The depolymerization was conducted at a pressure of 35 psig.

[0049] The reactor was air cooled to room temperature and the Parr reactor was opened. Crude BPA had solidified into a solid mass at the bottom of the glass sleeve. The liquid layer (45 grams of toluene with some water and organic impurities such as p-cumyl phenol) were decanted and discarded. The solids were removed from the glass sleeve and dried to give 67 grams of dried crude BPA with a purity of 99.7% 4,4’-isopropylidenediphenol.

BPA Purification

[0050] Following the large scale depolymerization describe above, the crude BPA (67 grams) was dissolved in 267 grams of hot toluene and allowed to cool to room temperature. The solids that crystallized upon cooling were isolated by filtration and dried to give 64 grams of off- white BPA having a purity of 99.7% 4,4’-isopropyiidenediphenol.

[0051] The BPA (64 grams) was recrystallized by heating in a mixture of 358 grams of toluene, 26 grams of isopropyl alcohol, and 0.3 grams of acetic acid (to neutralize the residual sodium carbonate). The mixture was allowed to cool to give 53 grams of white solids after drying with purity of 99.99% 4,4’-isopropyiidenediphenol. The initial solids isolated are a BPA-IPA adduct, which is converted to BPA by heating during the drying step.

[0052] This disclosure further encompasses the following aspects.

[0053] Aspect 1: A process for depolymerization of poly(carbonate), the process comprising: combining a poly(carbonate) comprising repeating units derived from bisphenol A; bisphenol A; water; and a base; under conditions effective to form a single liquid phase and to depolymerize the poly (carbonate).

[0054] Aspect 2: The process of aspect 1, wherein the process comprises combining the poly (carbonate), the bisphenol A, the water, the base, and an organic solvent

[0055] Aspect 3: The process of aspect 1 or 2, wherein the process further comprises isolating bisphenol A, and crystallizing the isolated bisphenol A with a crystallization solvent to provide a purified bisphenol A.

[0056] Aspect 4: The process of aspect 3, wherein the crystallization solvent comprises a mixture of toluene, isopropanol, and optionally, an organic acid, preferably acetic acid. [0057] Aspect 5: The process of any one of aspects 1 to 4, wherein the poly(carbonate) is a virgin poly(carbonate), a post-consumer recycled poly(carbonate), post-industrial recycled poly (carbonate), or a combination thereof.

[0058] Aspect 6: The process of any one of aspects 2 to 5, wherein the organic solvent comprises toluene, xylene, chlorobenzene, or a combination thereof.

[0059] Aspect 7: The process of any one of aspects 1 to 6, wherein the base comprises an alkali metal carbonate, an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium hydroxide, a phosphonium hydroxide, or a combination thereof.

[0060] Aspect 8: The process of any one of aspects 1 to 7, wherein the poly(carbonate) is present in an amount of 10 to 30 weight percent; the bisphenol A is present in an amount of 1 to 65 weight percent; the organic solvent is present in an amount of 5 to 65 weight percent; and the water is present in an amount of 5 to 35 weight percent; wherein weight percent of each component is based on the total weight of the poly(carbonate), the organic solvent, water, bisphenol A, and the base.

[0061] Aspect 9: The process of any one of aspects 1 to 8, wherein conditions effective to depolymerize the poly(carbonate) comprise a temperature of 110 to 130°C, preferably 115 to 125°C, and a pressure of 15 to 50 psig.

[0062] Aspect 10: The process of any one of aspects 1 to 9, wherein depolymerization of the poly(carbonate) is completed in 24 hours or less, preferably 16 hours or less, more preferably 10 hours or less, even more preferably 6 hours or less.

[0063] Aspect 11: The process of any one of aspects 3 to 10, wherein the purified bisphenol A is 4,4’-isopropylidenediphenol having a purity of greater than 99.8%.

[0064] Aspect 12: A process for isolation of bisphenol A from a depolymerized poly (carbonate), the process comprising: depolymerizing a poly(carbonate) according to the process of any of aspects 1 to 11; isolating bisphenol A; and crystallizing the isolated bisphenol A with a crystallization solvent to provide a purified bisphenol A; wherein the purified bisphenol A is 4,4’-isopropylidenediphenol having a purity of greater than 99.8%.

[0065] Aspect 13: A bisphenol A obtained the process of any one of aspects 3 to 12.

[0066] Aspect 14: The bisphenol A of aspect 13, wherein the bisphenol A is 4,4’- isopropylidenediphenol having a purity of greater than 99.8% and comprising less than 0.2 wt% of a monophenol.

[0067] Aspect 15: A thermoplastic polymer comprising repeating units derived from the bisphenol A of aspects 13 or 14, or isolated by the process of any one or more of aspects 3 to 12. [0068] Aspect 16: The thermoplastic polymer of aspect 15, wherein the thermoplastic polymer is a poly(etherimide) or a poly (carbonate).

[0069] Aspect 17: The thermoplastic polymer of aspect 15, wherein the thermoplastic polymer is a poly(etherimide).

[0070] Aspect 18: A method of making a poly(etherimide), the method comprising: isolating bisphenol A from depolymerization of a poly(carbonate) according to the process of any one or more of aspects 1 to 10; forming an aromatic bis(ether anhydride) from the isolated bisphenol A; and reacting the aromatic bis(ether anhydride) with an organic diamine to form the poly (etherimide) .

[0071] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles.

[0072] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. “Combinations” is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms“first,”“second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms“a” and“an” and“the” do not denote a limitation of quantity and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly

contradicted by context. “Or” means“and/or” unless clearly stated otherwise. Reference throughout the specification to“some aspects”,“an aspect”, and so forth, means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term“combination thereof’ as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements not named. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0073] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0074] 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 application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0075] Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency 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.

[0076] As used herein, the term“hydrocarbyl”, whether used by itself, or as a prefix, suffix, or fragment of another term, refers to a residue that contains only carbon and hydrogen. The residue can be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. It can also contain combinations of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when the hydrocarbyl residue is described as substituted, it may, optionally, contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue can also contain one or more carbonyl groups, amino groups, hydroxyl groups, or the like, or it can contain heteroatoms within the backbone of the hydrocarbyl residue. The term "alkyl" means a branched or straight chain, saturated aliphatic hydrocarbon group, e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n- pentyl, s-pentyl, and n- and s-hexyl. “Alkenyl” means a straight or branched chain, monovalent hydrocarbon group having at least one carbon-carbon double bond (e.g., ethenyl (-HC=CH2)). “Alkoxy” means an alkyl group that is linked via an oxygen (i.e., alkyl-O-), for example methoxy, ethoxy, and sec-butyloxy groups. "Alkylene" means a straight or branched chain, saturated, divalent aliphatic hydrocarbon group (e.g., methylene (-CH2-) or, propylene (-(CH2)3- )).“Cycloalky lene” means a divalent cyclic alkylene group, -CiThn-x, wherein x is the number of hydrogens replaced by cyclization(s). “Cycloalkenyl” means a monovalent group having one or more rings and one or more carbon-carbon double bonds in the ring, wherein all ring members are carbon (e.g., cyclopentyl and cyclohexyl). "Aryl" means an aromatic hydrocarbon group containing the specified number of carbon atoms, such as phenyl, tropone, indanyl, or naphthyl.“Arylene” means a divalent aryl group. “Alkylarylene” means an arylene group substituted with an alkyl group. “Arylalkylene” means an alkylene group substituted with an aryl group (e.g., benzyl). The prefix "halo" means a group or compound including one more of a fluoro, chloro, bromo, or iodo substituent. A combination of different halo groups (e.g., bromo and fluoro), or only chloro groups can be present. The prefix“hetero” means that the compound or group includes at least one ring member that is a heteroatom (e.g., 1, 2, or 3 heteroatom(s)), wherein the heteroatom(s) is each independently N, O, S, Si, or P. “Substituted” means that the compound or group is substituted with at least one (e.g., 1, 2, 3, or 4) substituents that can each independently be a C _1-9 alkoxy, a C _1-9 haloalkoxy, a nitro (-NO ₂ ), a cyano (-CN), a Ci- ₆ alkyl sulfonyl (-S(=0) ₂ -alkyl), a Ce-n aryl sulfonyl (-S(=0) ₂ -aryl), a thiol (-SH), a thiocyano (-SCN), a tosyl (CH3C6H4SO2-), a C3-12 cycloalkyl, a C2-12 alkenyl, a C5-12

cycloalkenyl, a Ce- aryl, a C _7-13 arylalkylene, a C _4-12 heterocycloalkyl, and a C _3-12 heteroaryl instead of hydrogen, provided that the substituted atom’s normal valence is not exceeded. The number of carbon atoms indicated in a group is exclusive of any substituents. For example - CH ₂ CH ₂ CN is a C ₂ alkyl group substituted with a nitrile.

[0077] While particular aspects have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.