EP3224297A1

EP3224297A1 - A method of adding a catalyst in a melt polymerization and the polycarbonate prepared therefrom

Info

Publication number: EP3224297A1
Application number: EP15798214.1A
Authority: EP
Inventors: Ignacio Vic Fernandez
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2014-11-25
Filing date: 2015-10-30
Publication date: 2017-10-04
Also published as: CN107001609A; KR20170089841A; WO2016083924A1

Abstract

In an embodiment, a method of forming a catalyst mixture comprises adding a dihydroxy compound, a carbonate compound, and a catalyst compound to form the catalyst mixture in any order, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound; wherein the catalyst compound is not exposed to a water and/or an alkyl alcohol level of greater than 250 ppm based on the total weight of the catalyst mixture. In another embodiment, a method of polymerizing polycarbonate comprises directing a catalyst mixture to a melt polymerization unit; and melt polymerizing to form the polycarbonate.

Description

A METHOD OF ADDING A CATALYST IN A MELT POLYMERIZATION AND THE POLYCARBONATE PREPARED THEREFROM

TECHNICAL FIELD

[0001] This application relates to a method of adding a catalyst in a melt polymerization and the polycarbonate made therefrom.

BACKGROUND

[0002] European Patent 2,540,758 is directed towards a melt polymerization reactor system and method of producing polycarbonate using a late-addition catalyst formulation having a melt transesterification catalyst dispersed in a liquid carrier system.

[0003] U.S. Patent No. 7,057,004 is directed towards a method of reducing color generated during production of copolycarbonate. The method includes steps of preparing a reaction mixture containing precursors of monomer residues, selecting a catalyst introduction strategy, and adding catalysts according to the strategy.

[0004] Improved methods of preparing melt polycarbonate are desired, for example, to produce melt polycarbonate with improved properties.

BRIEF DESCRIPTION

[0005] Disclosed herein is a melt polycarbonate and methods for making the same.

[0006] In an embodiment, a method of forming a catalyst mixture comprises adding a dihydroxy compound, a carbonate compound, and a catalyst compound to form the catalyst mixture in any order, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound; wherein the catalyst compound is not exposed to a water level of greater than 250 ppm based on the total weight of the catalyst mixture.

[0007] In an embodiment, a method of forming a catalyst mixture comprises adding, in any order, a dihydroxy compound, a carbonate compound, and a catalyst compound to form the catalyst mixture, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound; wherein the catalyst compound is not exposed to an alkyl alcohol level of greater than 250 ppm based on the total weight of the catalyst mixture.

[0008] In another embodiment, a method of polymerizing polycarbonate comprises directing a catalyst mixture to a melt polymerization unit; and melt polymerizing to form the polycarbonate. [0009] The above described and other features are exemplified by the following detailed description.

DETAILED DESCRIPTION

[0010] In melt polymerization processes of polymerizing polycarbonate, a catalyst mixture comprising the reactants and a catalyst comprising one or both of a quaternary ammonium compound and a quaternary phosphonium compound (hereinafter referred to as the catalyst compound) is generally prepared prior to polymerization. It was found that water and/or an alkyl alcohol contaminant in the catalyst mixture disadvantageously resulted in an increase in side reactions of the dihydroxy monomer. It was surprisingly discovered that by controlling the addition conditions of the monomers and the catalyst compound into the catalyst mixture, the side reaction with water and/or an alkyl alcohol could be significantly reduced. The method comprises adding, in any order, a dihydroxy compound, a carbonate compound, and the catalyst compound to form a catalyst mixture; wherein the catalyst compound is not exposed to a solvent carrier level of greater than 250 parts per million by weight (ppm) based on the total weight of the catalyst mixture, wherein the solvent can comprise water and alkyl alcohol (such as methanol, ethanol, pentanol, butanol, hexanol, and the like) or a combination comprising one or both of the foregoing. The catalyst compound can be exposed to a water level of the catalyst compound of less than or equal to 250 ppm based on the total weight of the catalyst mixture. The catalyst compound can be exposed to an alkyl alcohol level of less than or equal to 250 ppm based on the total weight of the catalyst mixture. For example, the method can comprise adding a dihydroxy compound and a carbonate compound to a monomer mixing vessel at a temperature greater than or equal to the melting temperature of the carbonate compound; a water level in the monomer mixture can be reduced such that the water level is less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound; and adding the catalyst compound.

[0011] For example, the method can comprise adding a dihydroxy compound and a carbonate compound to a monomer mixing vessel at a temperature greater than or equal to the melting temperature of the carbonate compound; an alkyl alcohol level in the monomer mixture can be reduced to such that the alkyl alcohol level is less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound; and adding the catalyst compound.

[0012] The method can result in a change in endcapping ratio of a polycarbonate of less than or equal to 5%, specifically, less than or equal to 3%, more specifically, less than or equal to 1 % relative to a polycarbonate polymerized under the same conditions, but that is polymerized in the presence of no measurable amount of water and an alkyl alcohol (based upon measurement standards as of November 15, 2014) in the monomer mixture. As used herein, the endcapping ratio in percent (%EC) is determined by the following equation:

wherein ppm OH is the amount of hydroxyl end groups in ppm and Mn is the number averaged molecular weight based on polycarbonate standards in Daltons. The ppm OH can be determined by Fourier Transform Infrared Spectroscopy (FTIR), for example, on a Perkin Elmer FTIR Spectrum One Device by dissolving 0.5 grams (g) of the polycarbonate sample in 25 milliliters (mL) of dried chloroform, measuring the absorbance at a wavelength of 3,584 inverse centimeters (cm ¹) using a univariable calibration, and normalizing the absorbance by dividing the absorbance by the absorbance at 2,779 cm^"1.

[0013] "Polycarbonate" as used herein means a polymer having repeating structural carbonate units of formula (1), in which at least 60 percent of the total number of R¹ groups contain aromatic moieties and the balance thereof are aliphatic, alicyclic, or aromatic. Each R¹ can be a C6-30 aromatic group, that is, contains at least one aromatic moiety. R¹ can be derived from an aromatic dihydroxy compound of the formula HO-R^OH, in particular of

1 2 1 formula (2), wherein each of A and A is a monocyclic divalent aromatic group and Y is a

1 2 single bond or a bridging group having one or more atoms that separate A from A . One

1 2 1

atom can separate A from A . Specifically, each R can be derived from a bisphenol of formula (3), wherein R^a and R^b are each independently a halogen, CM2 alkoxy, or Ci_i2 alkyl; and p and q are each independently integers of 0 to 4. It will be understood that when p or q is less than 4, the valence of each carbon of the ring is filled by hydrogen. Also in formula (3), X^a is a bridging group connecting the two hydroxy-substituted aromatic groups, where the bridging group and the hydroxy substituent of each C arylene group are disposed ortho, meta, or para (specifically para) to each other on the arylene group. The bridging group X^a can be a single bond, -0-, -S-, -S(O)-, -S(0)2-, -C(O)-, or a CMS organic group. The CMS 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 arylene groups connected thereto are each connected to a common alkylidene carbon or to different carbons of the CMS organic bridging group. Each p and q can be 1 , and R^a and R^b can each be a Ci_3 alkyl group, s ecifically methyl, disposed meta to the hydroxy group on each arylene group.

[0014] X^a can be a substituted or unsubstituted C3_is cycloalkylidene, a Ci_25 alkylidene of formula -C(R^c)(R^d)- wherein R^c and R^d are each independently hydrogen, alkyl, CH2 cycloalkyl, Cj.n arylalkyl, CM2 heteroalkyl, or cyclic C_7-i2 heteroarylalkyl, or a group of the formula -C(=R^e)- wherein R^e is a divalent C_\-n hydrocarbon group. Groups of this type include methylene, cyclohexylmethylene, ethylidene, neopentylidene, and isopropylidene, as well as 2-[2.2. 1]-bicycloheptylidene, cyclohexylidene, cyclopentylidene, cyclododecylidene, and adamantylidene.

[0015] X^A can be a CMS alkylene, a C3_is cycloalkylene, a fused C6-is cycloalkylene,

1 2 1 2

or a group of the formula -B -G-B - wherein B and B are the same or different Ci-6 alkylene and G is a C3_i2 cycloalkylidene or a C(,-_\e arylene. For example, X^A can be a substituted C₃-18 cycloalkylidene of formula (4), wherein R^r, R^p, R^q, and R^l are each independently hydrogen, halogen, oxygen, or Ci_i2 hydrocarbon groups; Q is a direct bond, a carbon, or a divalent oxygen, sulfur, or -N(Z)- where Z is hydrogen, halogen, hydroxy, Ci-12 alkyl, CM2 alkoxy, or Ci_i2 acyl; r is 0 to 2, t is 1 or 2, q is 0 or 1 , and k is 0 to 3, with the proviso that at least two of R^r, R^p, R^q, and R^l taken together are a fused cycloaliphatic, aromatic, or heteroaromatic ring. It will be understood that where the fused ring is aromatic, the ring as shown in formula (4) will have an unsaturated carbon-carbon linkage where the ring is fused. When k is one and i is 0, the ring as shown in formula (4) contains 4 carbon atoms, when k is 2, the ring as shown in formula (4) contains 5 carbon atoms, and when k is 3, the ring contains 6 carbon atoms. Two adjacent groups (e.g., R^q and R^l taken together) can form an aromatic group, and R^q and R^l taken together can form one aromatic group and R^r and R^p taken together can form a second aromatic group. When R^q and R^l taken together form an aromatic group, R^p can be a double-bonded oxygen atom, i.e., a ketone.

[0016] Bisphenols wherein X^a is a cycloalkylidene of formula (4) can be used in the manufacture of polycarbonates containing phthalimidine carbonate units of formula (la), wherein R^a, R^b, p, and q are as in formula (3), R³ is each independently a Ci_6 alkyl, j is 0 to 4, and R4 is hydrogen, Ci_6 alkyl, or a substituted or unsubstituted phenyl, for example, a phenyl substituted with up to five Ci_6 alkyls. For example, the phthalimidine carbonate units are of formula (lb), wherein R⁵ is hydrogen, phenyl optionally substituted with up to five 5 Ci_6 alkyls, or Ci_₄ alkyl. In formula (lb), R⁵ can be hydrogen, methyl, or phenyl, specifically, phenyl. Carbonate units (lb) wherein R⁵ is phenyl can be derived from 2- phenyl-3,3'-bis(4-hydroxy phenyl)phthalimidine (also known as 3,3-bis(4-hydroxyphenyl)-2- phenylisoindolin-l-one, or N-phenyl phenolphthalein bisphenol ("PPPBP")).

[0017] Other bisphenol carbonate repeating units of this type are the isatin carbonate units of formula (lc) and (Id), wherein R^a and R^b are each independently C1 2 alkyl, p and q are each independently 0 to 4, and R¹ is Ci_i2 alkyl, phenyl, optionally substituted with 1 to 5 Ci_io alkyl, or benzyl optionally substituted with 1 to 5 Ci_io alkyl. Each R^a and R^b can be methyl, l.

[0018] Other examples of bisphenol carbonate units derived from bisphenols (3) wherein X^a is a substituted or unsubstituted C3_is cycloalkylidene (4) include the

cyclohexylidene-bridged, alkyl-substituted bisphenol of formula (le)

wherein R^a and R^b are each independently Ci_i2 alkyl, R^g is Ci-u alkyl, p and q are each independently 0 to 4, and t is 0 to 10. At least one of each of R^a and R^b can be disposed meta to the cyclohexylidene bridging group. Each R^a and R^b can independently be Cj_₄ alkyl, R^g is Ci_4 alkyl, p and q are each 0 or 1 , and t is 0 to 5. R^a, R^b, and R^g can each be methyl, p and q can each be 0 or 1 , and t can be 0 or 3, specifically, 0.

[0019] Examples of other bisphenol carbonate units derived from bisphenol (3) wherein X^a is a substituted or unsubstituted C3_is cycloalkylidene include adamantyl units of formula (If) and fluorenyl units of formula (lg), wherein R^a and R^b are each independently Ci-12 alkyl, and p and q are each independently 1 to 4. At least one of each of R^a and R^b can be disposed meta to the cycloalkylidene bridging group. R^a and R^b can each be

a b

independently Ci_3 alkyl, and p and q can be each 0 or 1 ; specifically, R , R can each be methyl, p and q are each 0 or 1, and when p and q are 1 , the methyl group can be disposed meta to the cycloalkylidene bridging group. Carbonates containing units (la) to (lg) are useful for making polycarbonates with high glass transition temperatures (Tg) and high heat distortion temperatures.

[0020] Other useful dihydroxy compounds of the formula HO-R^OH include aromatic dihydroxy compounds of formula (6), wherein each R^h is independently a halogen atom, Ci-io hydrocarbyl group such as a CMO alkyl, a halogen-substituted CMO alkyl, a 0_6-ιο aryl, or a halogen-substituted 0_6-ιο aryl, and n is 0 to 4. The halogen is usually bromine.

[0021] Some illustrative examples of specific dihydroxy compounds include the following: 4,4'-dihydroxybiphenyl, 1 ,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4- hydroxyphenyl)- 1 -naphthylmethane, 1 ,2-bis(4-hydroxyphenyl)ethane, 1 , 1 -bis(4- hydroxyphenyl)- 1 -phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, bis(4- hydroxyphenyl)phenylme thane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 1 , 1 -bis (hydroxyphenyl)cyclopentane, 1 , 1 -bis(4-hydroxyphenyl)cyclohexane, 1 , 1 -bis(4-hydroxy phenyl)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, 1 , 1 -dichloro-2,2-bis(5-phenoxy-4-hydroxy phenyl)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)fluorine, 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 combinations comprising at least one of the foregoing.

[0022] Specific examples of bisphenol compounds of formula (3) include l,l-bis(4- hydroxyphenyl) methane, l,l-bis(4-hydroxyphenyl) ethane, 2,2-bis(4-hydroxyphenyl) propane (hereinafter "bisphenol A" or "BPA"), 2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4- hydroxyphenyl) octane, l,l-bis(4-hydroxyphenyl) propane, l,l-bis(4-hydroxyphenyl) n- butane, 2,2-bis(4-hydroxy-2-methylphenyl) propane, l,l-bis(4-hydroxy-t-butylphenyl) propane, 3,3-bis(4-hydroxyphenyl) phthalimidine, 2-phenyl-3,3-bis(4-hydroxyphenyl) phthalimidine (PPPBP), and l,l-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinations comprising at least one of the foregoing dihydroxy compounds can also be used. The polycarbonate can be a linear homopolymer derived from bisphenol A, in which each of A and A is p-phenylene and Y is isopropylidene in formula (3).

[0023] The polycarbonate herein is prepared via the melt polymerization of a bisphenol and a carbonate precursor. Exemplary carbonate precursors include a carbonyl halide such as carbonyl bromide or carbonyl chloride (phosgene) a bishaloformate of a dihydroxy compound (e.g., the bischloroformate of bisphenol A, hydroquinone ethylene glycol, neopentyl glycol, or the like), and diaryl carbonates. Combinations comprising at least one of the foregoing types of carbonate precursors can also be used. The diaryl carbonate ester can be diphenyl carbonate, or an activated diphenyl carbonate having electron-withdrawing substituents on each aryl, such as bis(4-nitrophenyl)carbonate, bis(2- chlorophenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate, bis(4- methylcarboxylphenyl) carbonate, bis(2-acetylphenyl) carboxylate, bis(4-acetylphenyl) carboxylate, or a combination comprising at least one of the foregoing. The diaryl carbonate ester (also referred to as the carbonate compound) can be free of an activated diphenyl carbonate having electron-withdrawing substituents on each aryl. For example, the diaryl carbonate ester can be free of bis(4-nitrophenyl)carbonate, bis(2-chlorophenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate, bis(4-methylcarboxylphenyl) carbonate, bis(2-acetylphenyl) carboxylate, and bis(4-acetylphenyl) carboxylate. The diaryl carbonate ester can be free of bis(methyl salicyl)carbonate. As used herein, "can be free of refers to none of the compound being added in the melt polymerization, for example, less than or equal to 10 ppm, for example, 0 ppm of the compound being present.

[0024] In the melt polymerization method, the polycarbonate can be prepared by co- reacting, in a molten state, a dihydroxy reactant and a carbonate precursor in the presence of a transesterification catalyst. The reaction can be carried out in typical polymerization equipment, such as a continuously stirred reactor (CSTR), plug flow reactor, wire wetting fall polymerizers, free fall polymerizers, horizontal polymerizers, wiped film polymerizers, BANBURY mixers, single or twin screw extruders, or a combination comprising one or more of the foregoing. Volatile monohydric phenol is removed from the molten reactants by distillation and the polymer is isolated as a molten residue. Melt polymerization can be conducted as a batch process or as a continuous process. In either case, the melt

polymerization conditions used can comprise two or more distinct reaction stages. For example, the polymerization can comprise an oligomerization stage in which the starting monomers are converted into an oligomeric polycarbonate and a second reaction stage also referred to as a polymerization stage wherein the oligomeric polycarbonate formed in the oligomerization stage is converted to high molecular weight polycarbonate. The

oligomerization stage can comprise 1 or more, specifically, 2 or more, more specifically, 2 to 4 oligomerization units (for example, 2 to 4 continuously stirred tanks). When 2 or more oligomerization units are present in series, one or both of an increase in temperature and a decrease in pressure can occur from one unit to the next. The polymerization stage can comprise 1 or more, specifically, 2 or more, more specifically, 2 polymerization units (for example, 2 horizontal or wire wetting fall polymerizers). The polymerization stage can comprise one or more polymerization units that can polymerize the polycarbonate to a molecular weight of, for example, 20 to 50 kilodaltons (kDa). After formation of a polycarbonate, the polycarbonate composition can then be optionally quenched and a devolatilized in a devolatization unit, where the molecular weight of the polycarbonate does not significantly increase (for example, the molecular weight does not increase by greater than 10 weight percent (wt%)) and a temperature, a pressure, and a residence time are used to reduce the concentration of low molecular weight components (such as those with a molecular weight of less than 1 kDa). The oligomerization unit is herein defined as a oligomerization unit that results in polycarbonates oligomers with a number average molecular weight of less than or equal to 8 kDa and a polymerization unit is herein defined as a polymerization unit that produces polycarbonate with a number average molecular weight of greater than 8 kDa. It is noted that while less than or equal to 8 kDa is used here to define a molecular weight achieved in the oligomerization stage, one skilled in the art readily understands that said molecular weight is used to define an oligomerization stage, where the oligomer molecular weight could be greater than 8 kDa. A "staged" polymerization reaction condition can be used in continuous polymerization, wherein the starting monomers are oligomerized in a first reaction vessel and the oligomeric polycarbonate is continuously transferred to one or more downstream reactors in which the oligomeric polycarbonate is converted to high molecular weight PC. Typically, in the oligomerization stage the oligomeric polycarbonate produced has a number average molecular weight (Mn) of 1 to 7.5 kDa using PC standard. In a subsequent polymerization stage the Mn of the PC can be increased to, for example, 8 and 25 kDa (using PC standard), specifically, 13 to 18 kDa.

[0025] Typically, solvents are not used in the process, and the reactants dihydroxy aromatic compound and the diaryl carbonate are in a molten state. The reaction temperature can be 100 to 350 degrees Celsius (°C), specifically, 180 to 310°C. The pressure can be at atmospheric pressure, supra-atmospheric pressure, or a range of pressures from atmospheric pressure to 15 torr in the initial stages of the reaction, and at a reduced pressure at later stages, for example, 0.2 to 15 torr. Likewise, the polymerization can occur in a series of polymerization vessels that can each individually have increasing temperature and/or vacuum. For example, an oligomerization stage can occur at a temperature of 100 to 280°C, specifically, 140 to 240°C and a polymerization stage can occur at a temperature of 240 to 350°C, specifically, 280 to 300°C or 240 to 270°C or 250 to 310°C, where the temperature in the polymerization stage is greater than the temperature in the oligomerization stage. The reaction time from the initial oligomerization unit to the final polymerization unit is generally 0.1 to 15 hours. A final polymerization unit as used herein refers to a final polymerization unit in the melt polymerization where the last increase in molecular weight occurs. For example, the quenching agent can be added to the polycarbonate resin after a final polymerization (e.g., after a point where the Mw of the polycarbonate resin will increase by less than or equal to 10%), and optionally, before any melt filtering.

[0026] Oligomerization can occur at a pressure of greater than or equal to 100 millibars absolute (mbara) or the oligomerization can comprise at least two oligomerization units where a first oligomerization unit can have a pressure of greater than or equal to 100 mbara and a second oligomerization can have a pressure of 15 to 90 mbara, where the first oligomerization unit is upstream of the second oligomerization unit, where one or more oligomerization units can be located before, in between, or after said polymerization units.

[0027] The polymerization stage following the oligomerization stage can comprise polymerizing in one or two polymerization units. The first polymerization unit can be at a temperature of 240 to 350°C, specifically, 260 to 310°C and a pressure of 1 to 10 mbar. The second polymerization unit can be at a temperature of 240 to 350°C, specifically, 260 to 300°C and a pressure of less than or equal to 5 mbar. The polycarbonate can be devolatized after a final polymerization. A final polymerization as used herein refers to a final polymerization, where the last increase in molecular weight occurs. For example, after a point where the Mw of the polycarbonate increases by less than or equal to 10%.

[0028] After a final polymerization vessel (also referred to as a final polymerization unit), the polymer can be introduced to a reactor, extruded, subjected to filtration in a melt filter, or a combination comprising one or more of the foregoing. It is noted that the melt filter can be located before or after the extruder. For example, the melt polymerization process for the manufacture of a polycarbonate composition can comprise: melt polymerizing a dihydroxy reactant and a carbonate compound to produce a molten reaction product; quenching the molten reaction product; filtering the molten reaction product in a melt filter upstream of any extruders; optionally, introducing an additive to form a mixture; and extruding the mixture to form the polycarbonate composition. Likewise, the melt polymerization process for the manufacture of a polycarbonate composition can comprise: melt polymerizing a dihydroxy reactant and a carbonate compound to produce a molten reaction product; introducing a quencher composition and optionally an additive to form a mixture; and extruding the mixture to form the polycarbonate composition.

[0029] The polycarbonate can be, for example, a bisphenol A polycarbonate with a weight average molecular weight of 21,800 Daltons (PC standards) with a melt flow of 24 to 32 g/10 min (ASTM D1238, 300°C, 2.16 kg).

[0030] The PC can have a melt flow of 4 to 40 g/10 min, e.g., 4.5 to 15 g/10 min or 15 to 35 g/10 min as determined by ASTM D1238 at 300°C, 1.5 kg. The PC can have a melt flow of 5 to 15 g/10 min as determined by ASTM D1238 at 250°C, 1.5 kg.

[0031] Catalysts used in the melt transesterification polymerization production of polycarbonates can include the catalyst compound and optionally an alkali catalyst comprising a source of one or both of alkali ions and alkaline earth ions.

[0032] The alkali catalyst is typically more thermally stable than the catalyst compound, and therefore can be used throughout transesterification, including during oligomerization, and after oligomerization, e.g., in the polymerization vessels, during polymerization. The alkali catalyst can be added to a polymerization at any stage in the polymerization, for example, upstream of, and/or directly to, and/or after a monomer mixing unit; and/or upstream of, and/or directly to, and/or after a polymerization unit (for example, to a first stage polymerization unit and/or the second reaction stage polymerization unit). Likewise, the catalyst addition process can be free of an alkali catalyst addition step.

[0033] The alkali catalyst comprises a source of one or both of alkali ions and alkaline earth ions. The sources of these ions include alkaline earth hydroxides such as magnesium hydroxide and calcium hydroxide. Sources of alkali metal ions can include the alkali metal hydroxides such as illustrated by lithium hydroxide, sodium hydroxide, potassium hydroxide, and combinations comprising at least one of the foregoing. Examples of alkaline earth metal hydroxides are calcium hydroxide, magnesium hydroxide, and combinations comprising at least one of the foregoing. The alkali catalyst can comprise sodium hydroxide. The alkali catalyst typically will be used in an amount sufficient to provide 1 x 10 -^"2 to 1 x 10 -^"8 moles, specifically, 1 x 10 -4 to 1 x 10 -^"7 moles of metal hydroxide per mole of the dihydroxy compounds employed. Other possible sources of alkaline earth and alkali metal ions include salts of carboxylic acids (such as sodium acetate) and derivatives of ethylene diamine tetraacetic acid (EDTA) (such as EDTA tetrasodium salt, and EDTA magnesium disodium salt), as well as combinations comprising at least one of the foregoing. For example, the alkali catalyst can comprise alkali metal salt(s) of a carboxylic acid, alkaline earth metal salt(s) of a carboxylic acid, or a combination comprising at least one of the foregoing. The alkali catalyst can comprise Na2Mg EDTA or a salt thereof.

[0034] The alkali catalyst can also, or alternatively, comprise salt(s) of a non-volatile inorganic acid. For example, the alkali catalyst can comprise salt(s) of a non-volatile inorganic acid such as NaH₂ P0₃, NaH₂P0₄, Na₂HP0₃, KH₂P0₄, CsH₂P0₄, Cs₂HP0₄, or a combination comprising at least one of the foregoing. Alternatively, or in addition, the alkali catalyst can comprise mixed alkali metal salt(s) of phosphoric acid, such as NaKHP0₄, CsNaHP0₄, CsKHP0₄, and combinations comprising at least one of the foregoing. The alkali catalyst can comprise KNaHP0₄, wherein a molar ratio of Na to K is 0.5 to 2.

[0035] The catalyst compound can comprise a quaternary ammonium compound, a quaternary phosphonium compound, or a combination comprising at least one of the foregoing. The quaternary ammonium compound can be a compound of the structure (R⁴)₄N⁺X^~, wherein each R⁴ is the same or different, and is a Q_₂o alkyl, a C₄_₂o cycloalkyl, or a C₄_₂o aryl; and X^" is an organic or inorganic anion, for example, a hydroxide, halide, carboxylate, sulfonate, sulfate, formate, carbonate, or bicarbonate. Examples of organic quaternary ammonium compounds include tetramethyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetramethyl ammonium acetate, tetramethyl ammonium formate, tetrabutyl ammonium acetate, and combinations comprising at least one of the foregoing. Tetramethyl ammonium hydroxide is often used.

[0036] The quaternary phosphonium compound can be a compound of the structure (R⁵)₄P⁺X^~, wherein each R⁵ is the same or different, and is a Ci_₂o alkyl, a C₄_₂o cycloalkyl, or a C₄_₂o aryl; and X^" is an organic or inorganic anion, for example, a hydroxide, phenoxide, halide, carboxylate such as acetate or formate, sulfonate, sulfate, formate, carbonate, or bicarbonate. Where X^" is a polyvalent anion such as carbonate or sulfate, it is understood that the positive and negative charges in the quaternary ammonium and phosphonium structures are properly balanced. For example, where R 20 to R 23 are each methyls and X^" is carbonate, it is understood that X^" represents 2(CC -2

>3^~ ).

[0037] Examples of organic quaternary phosphonium compounds include tetramethyl phosphonium hydroxide, tetramethyl phosphonium acetate, tetramethyl phosphonium formate, tetrabutyl phosphonium hydroxide, tetraphenyl phosphonium acetate (TPPA), tetraphenyl phosphonium phenoxide (TPPP), tetraethyl phosphonium acetate, tetrapropyl phosphonium acetate, tetrabutyl phosphonium acetate, tetrapentyl phosphonium acetate, tetrahexyl phosphonium acetate, tetraheptyl phosphonium acetate, tetraoctyl phosphonium acetate, tetradecyl phosphonium acetate, tetradodecyl phosphonium acetate, tetratolyl phosphonium acetate, tetramethyl phosphonium benzoate, tetraethyl phosphonium benzoate, tetrapropyl phosphonium benzoate, tetraphenyl phosphonium benzoate, tetraethyl phosphonium formate, tetrapropyl phosphonium formate, tetraphenyl phosphonium formate, tetramethyl phosphonium propionate, tetraethyl phosphonium propionate, tetrapropyl phosphonium propionate, tetramethyl phosphonium butyrate, tetraethyl phosphonium butyrate, and tetrapropyl phosphonium butyrate, and combinations comprising at least one of the foregoing. The catalyst compound can comprise TPPP, TPPA, or a combination comprising one or both of the foregoing.

[0038] The amount of catalyst compound employed is typically based upon the total number of moles of dihydroxy compound employed in the polymerization reaction. When referring to the ratio of catalyst compound, for example, phosphonium salt, to all dihydroxy compounds employed in the polymerization reaction, it is convenient to refer to moles of phosphonium salt per mole of the dihydroxy compound(s), meaning the number of moles of phosphonium salt divided by the sum of the moles of each individual dihydroxy compound present in the reaction mixture. The amount of catalyst compound (e.g., organic ammonium or phosphonium salts) employed typically will be 1 x 10^"2 to 1 x 10^"5, specifically, 1 x 10^"3 to 1 x 10^"4 moles per total mole of the dihydroxy compounds in the catalyst mixture.

[0039] The catalyst compound can have a reduced concentration of alkali metal salts. The catalyst compound can comprise one or more of: a) less than or equal to 2,000 ppm, specifically, less than or equal to 1,675 ppm, specifically, less than or equal to 500 ppm, more specifically, less than or equal to 100 ppm, even more specifically, less than or equal to 30 ppm of sodium; b) less than or equal to 500 ppm, specifically, less than or equal to 300 ppm, more specifically, less than or equal to 135 ppm; and c) less than or equal to 100 ppm, specifically, less than or equal to 45 ppm of potassium; based on the total weight of the catalyst compound.

[0040] The catalyst compound can comprise an alkali metal compound, wherein if the metal compound comprises sodium sulfate, the amount of sodium can be less than or equal to 1,690 ppm, specifically, less than or equal to 1,670 ppm based on the total weight of the catalyst compound; if the metal compound comprises cesium sulfate, the amount of cesium can be less than or equal to 275 ppm, specifically, less than or equal to 252 ppm based on the total weight of the catalyst compound; if the metal compound comprises sodium hydroxide, the amount of sodium can be less than or equal to 35 ppm, specifically, less than or equal to 29 ppm based on the total weight of the catalyst compound; if the metal compound comprises potassium hydroxide, the amount of potassium can be less than or equal to 50 ppm, specifically, less than or equal to 43 ppm based on the total weight of the catalyst compound; if the metal compound comprises cesium hydroxide, the amount of cesium can be less than or equal to 140 ppm, specifically, less than or equal to 132 ppm based on the total weight of the catalyst compound; or a combination comprising one or more of the foregoing.

[0041] The catalyst compound can comprise an alkali metal compound, wherein the amount of sodium can be greater than or equal to 1 ppm, or greater than or equal to 30 ppm, or greater than or equal to 100 ppm; the amount of cesium can be greater than or equal to 10 ppm, or greater than or equal to 30 ppm, or greater than or equal to 50 ppm; the amount of potassium can be greater than 0 ppm, or greater than or equal to 5 ppm, or greater than or equal to 10 ppm; or a combination comprising one or more of the foregoing, wherein the metal amounts are based on the weight of the catalyst compound.

[0042] The catalyst compound can be added to a monomer mixing unit located upstream of a polymerization unit. The monomer mixture can comprise less than or equal to 500 ppm of one or both of water and an alkyl alcohol based on the total weight of the monomer mixture, for example, arising from one or more of the dihydroxy compound, the carbonate compound, and the atmosphere in the monomer mixing unit. The water and/or the alkyl alcohol level can be reduced prior to adding a catalyst compound. It was surprisingly found that reducing the water and/or the alkyl alcohol level in the monomer mixture such that the catalyst compound is not exposed to a water and/or an alkyl alcohol level of greater than 500 ppm based on the total weight of the mixture reduces the occurrence of unwanted side reactions, such as those that would occur between water and/or alkyl alcohol and BPA in the presence of the catalyst compound.

[0043] The catalyst mixture can have a dihydroxy compound to carbonate compound molar ratio of 0.5: 1 to 1.5:1, specifically, 0.9: 1 to 1.1: 1, more specifically, 0.99: 1 to 1.01 :1.

[0044] The method of adding a catalyst compound can comprise adding a dihydroxy compound, a carbonate compound, and the catalyst compound to form the catalyst mixture in any order; wherein the catalyst compound is not exposed to a water and/or an alkyl alcohol level of greater than 250 ppm based on the total weight of the catalyst mixture. The catalyst mixture can comprise less than or equal to 250 ppm, specifically, less than or equal to 130 ppm, more specifically, less than or equal to 50 ppm of one or both of an alkyl alcohol and water based on the total weight of the mixture, for example, comprising the catalyst compound, the dihydroxy compound, and the carbonate compound. The adding can be performed in an inert atmosphere, for example, under nitrogen and/or argon. As used herein, an inert atmosphere refers to a gaseous atmosphere, wherein the gaseous atmosphere is unreactive with the components in the mixture.

[0045] The catalyst compound can be added to a monomer mixing unit located upstream of an oligomerization unit. For example, the method of adding the catalyst compound can comprise adding the catalyst compound and one or both of a dihydroxy monomer and a carbonate compound to the monomer mixing unit in any order to form a catalyst mixture. When the catalyst mixture comprises both the dihydroxy monomer and the carbonate compound, then the adding can comprise first adding the dihydroxy monomer and the carbonate compound in any order and then adding the catalyst compound; first adding the catalyst compound and then adding the dihydroxy monomer and the carbonate compound in any order; or adding one of the dihydroxy monomer and the carbonate compound, adding the catalyst compound, and then adding the other of the dihydroxy monomer and the carbonate compound. When the catalyst mixture comprises one of the dihydroxy monomer and the carbonate compound, then the adding can comprise adding one of the dihydroxy monomer and the carbonate compound to the monomer mixing unit and then adding the catalyst compound or adding the catalyst compound to the monomer mixing unit and then adding one of the dihydroxy monomer and the carbonate compound. Likewise, two or more components can be added simultaneously. The carbonate compound can be molten during the adding or can be added and subsequently melted. The dihydroxy compound can be added as a solid to the molten carbonate compound.

[0046] The water and/or an alkyl alcohol level can be reduced in one or more reducing steps prior to adding the catalyst compound. The reducing the water and/or the alkyl alcohol level can be accomplished by maintaining a temperature and pressure in the monomer mixing unit above the boiling point of water and/or an alkyl alcohol for an amount of time to reduce the water and/or an alkyl alcohol level. For example, the reducing the water level at atmospheric pressure can be accomplished by maintaining a temperature in the monomer mixing unit of greater than or equal to 100°C for an amount of time to reduce the water level. The temperature in the monomer mixing unit can be 100 to 250°C, specifically, 150 to 200°C, more specifically, 165 to 185°C. [0047] The method of adding a catalyst compound can comprise adding a dihydroxy compound and a carbonate compound to the monomer mixing unit at a temperature greater than or equal to the melting temperature of the carbonate compound; reducing a water and/or an alkyl alcohol level in the monomer mixture to less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound; and adding the catalyst compound to the monomer mixture to form the catalyst mixture.

[0048] The method of adding a catalyst compound can comprise adding a dihydroxy compound and reducing a water and/or an alkyl alcohol level to less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound; adding a carbonate compound and reducing one or both of the alkyl alcohol and the water level to less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and adding the catalyst compound to the monomer mixture to form the catalyst mixture. The adding the carbonate compound can occur before or after adding the dihydroxy compound.

[0049] Adding the catalyst compound can comprise adding a carbonate compound comprising less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm of water and/or an alkyl alcohol based on the total weight of the carbonate compound; adding a dihydroxy compound comprising less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm of water and/or an alkyl alcohol based on the total weight of the dihydroxy compound; and adding the catalyst compound in any order to form the catalyst mixture.

[0050] The monomer mixing unit can be at atmospheric pressure. The monomer mixing unit can be maintained at a temperature of 100 to 250°C, specifically, 150 to 200°C, more specifically, 165 to 185°C.

[0051] The polymerization process can comprise a section of parallel polymerization, where parallel polymerization refers to the splitting of a polycarbonate stream into two or more streams that may or may not experience the same polymerization conditions thereafter (i.e., they can attain different molecular weights, have different additives added thereto, etc.). For example, polycarbonate can be prepared in a first portion of the polymerization process; a stream comprising polycarbonate can be split into two or more streams and directed to 2 or more parallel operating lines. For example, a method can comprise polymerizing polycarbonate in a series of oligomerization polymerization units; a stream exiting the oligomerization stage can be split into two streams: A and B, where stream A is directed to polymerization unit A and stream B is directed to polymerization unit B. Likewise, a method can comprise polymerizing polycarbonate in a series of oligomerization units followed by polymerizing in a series of polymerization units; a stream exiting the polymerization stage can be split into two streams: A and B, where stream A is directed to extruder A and stream B is directed to extruder B. A method can comprise polymerizing polycarbonate in a series of oligomerization units followed by polymerizing in a series of two polymerization units; a stream exiting the first polymerization unit can be split into two streams: A and B, where stream A is directed to second polymerization unit A and stream B is directed to second polymerization unit B. In any of the aforementioned scenarios, a quencher composition can be added to one or both of streams A and B, where the quencher composition can be the same or different. One skilled in the art can readily envision other embodiments comprising more than 2 parallel streams and embodiments where the streams are split at different locations.

[0052] A quencher composition can be added at one or more locations in the present melt preparation of the polycarbonate to reduce the activity of the catalyst. The quencher composition comprises a quenching agent (also referred to herein as a quencher). For example, the quenching agent can comprise a sulfonic acid ester such as an alkyl sulfonic ester of the formula R₁SO₃R2 wherein Rj is hydrogen, Ci-₁2 alkyl, C₆-i8 aryl, or C7-19 alkylaryl, and R2 is Q-₁2 alkyl, C₆-i8 aryl, or C7-19 alkylaryl. Examples of alkyl sulfonic esters include benzenesulfonate, p-toluenesulfonate, methylbenzene sulfonate, ethylbenzene sulfonate, n-butyl benzenesulfonate, octyl benzenesulfonate and phenyl benzenesulfonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, n-butyl p-toluene sulfonate, octyl p- toluenesulfonate and phenyl p- toluenesulfonate. The sulfonic acid ester can comprise alkyl tosylates such as n-butyl tosylate. The sulfonic acid ester can be present in the quencher composition in an amount of 0.1 to 10 volume percent (vol ), specifically, 0.1 to 5 vol , more specifically, 0.5 to 2 vol based on the total volume of the quencher composition.

[0053] The quenching agent can comprise zinc borate, boron phosphate, boric acid esters (e.g., Β((Χ¾)3, B(OCH2CH₃)3, and Β(0€6¾)3), aluminum stearate, aluminum silicate, zirconium carbonate, zirconium Ci-12 alkoxides, zirconium hydroxycarboxylates, gallium phosphide, gallium antimonide, germanium oxide, Ci-32 organogermanium compounds, C4-32 tetraorganotin tin compound, Q-32 hexaorganotin compound (e.g., Sl^Os, [(C₆HeO)Sn(CH2CH2CH2CH₃)2]20), antimony oxide, Ci-32 alkylantimony, bismuth oxide, Ci-12 alkylbismuth, zinc acetate, zinc stearate, Ci-32 alkoxytitanium, and titanium oxide, phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, boric acid, polyphosphoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, sulfurous acid, adipic acid, azelaic acid, dodecanoic acid, L-ascorbic acid, aspartic acid, benzoic acid, formic acid, acetic acid, citric acid, glutamic acid, salicylic acid, nicotinic acid, fumaric acid, maleic acid, oxalic acid, benzenesulfinic acid, Q-12 dialkyl sulfates (e.g., dimethyl sulfate and dibutyl sulfate), sulfonic acid phosphonium salts of the formula (R^aS0₃ ^~)(PR^b4)⁺ wherein R^a is hydrogen, Ci-12 alkyl, Q-18 aryl, or C7-19 alkylaryl, and each R^b is independently hydrogen, Ci-12 alkyl or Q-18 aryl, sulfonic acid derivatives of the formula A¹-(Y¹-S0₃X¹)_m wherein A¹ is a Q-40 hydrocarbon group having a valence of m, Y¹ is a single bond or an oxygen atom, X¹ is a secondary or tertiary alkyl group of the formula -CR¹⁵R¹⁶R¹⁷, a metal cation of one equivalent, an ammonium cation (e.g., NR^b ₃ ⁺ wherein each R^b is independently hydrogen, Q- 12 alkyl or Q-18 aryl), or a phosphonium (e.g., PR^b ₄ ⁺ wherein each R^b is independently H, Q- 12 alkyl or C₆-i8 aryl) wherein R¹⁵ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R¹⁶ is a hydrogen atom, a phenyl group or an alky group having 1 to 5 carbon atoms, and R¹⁷ is the same as or different from R¹⁵ and has the same definition as R¹⁵, provided that two of R¹⁵, R¹⁶, and R¹⁷ cannot be hydrogen atoms, and m is an integer of 1 to 4, provided that when Y¹ is a single bond, all of X¹ in an amount of m cannot be metal cations of one equivalent, a compound of the formula ⁺X²-A²-Y¹-S0₃ ^~ wherein A² is a divalent hydrocarbon group, ⁺X² is a secondary, tertiary or quaternary ammonium cation or a secondary (e.g., tertiary or quaternary phosphonium cation, and Y¹ is a single bond or an oxygen atom, a compound of the formula A³-(⁺X³)_n- (R-Y¹-S0₃ ^")_n wherein A³ is a Ci-40 hydrocarbon group having a valence of n, ⁺X³ is a secondary, tertiary or quaternary ammonium cation (e.g., NR^b3⁺ wherein each R^b is independently hydrogen, Q-12 alkyl or C₆-i8 aryl), or a secondary, tertiary or quaternary phosphonium cation (e.g., PR^b4⁺ wherein each R^b is independently hydrogen, Q-12 alkyl or C₆-i8 aryl), R is a monovalent Ci-40 hydrocarbon group, n is an integer of 2 to 4, and Y¹ is a single bond or an oxygen atom, a compound of the formula A⁵- Ad¹-A⁴-(Ad²-A⁵)_t wherein A⁵ is a monovalent or divalent Ci-40 hydrocarbon group, A is a divalent Q n group, each of Ad 1 and Ad 2

-40 hydrocarbo is independently an acid anhydride group selected from -SO2-O-SO2-, -SO2-O-CO- and -CO-O-SO2-, and £ is 0 or 1, provided that when £ is O, -(Ad²-A⁵)_t is a hydrogen atom or a bond between A⁴ and A⁵, in which A⁵ is a divalent hydrocarbon group or a single bond, aminosulfonic esters having the formula R_aR_bN-A-S0₃R_c, wherein R_a and R_b are each independently hydrogen, Q-12 alkyl, Ce-22 aryl, C7-19 alkylaryl or R_a and R_b, either singly or in combination, form an aromatic or non- aromatic heterocyclic compound with N (e.g., pyrrolyl, pyridinyl, pyrimidyl, pyrazinyl, carbazolyl, quinolinyl, imidazoyl, piperazinyl, oxazolyl, thiazolyl, pyrazolyl, pyrrolinyl, indolyl, purinyl, pyrrolydinyl, or the like), R_c is hydrogen, and A is Q-12 alkyl, C6-18 aryl, or C17-1 alkylaryl (e.g., compounds such as N-(2-hydroxyethyl) piperazine-N'-3-propane sulfonic acid, 1 ,4,-piperazinebis (ethanesulfonic acid), and 5-dimethylamino-l-napthalene sulfonic acid), ammonium sulfonic esters of the formula R_aR_bR_cN⁺— A— SO₃ ^", wherein R_a, R_b, are each independently hydrogen, Q-12 alkyl, Q-12 aryl, C7-19 alkylaryl, or R_a and R_b, either singly or in combination, form an aromatic or non-aromatic heterocyclic compound with N (e.g., pyrrolyl, pyridinyl, pyrimidyl, pyrazinyl, carbazolyl, quinolinyl, imidazoyl, piperazinyl, oxazolyl, thiazolyl, pyrazolyl, pyrrolinyl, indolyl, purinyl, pyrrolydinyl, or the like), R_c is a hydrogen, and A is C_n2 alkyl, C6-18 aryl, or C₇-j9 alkylaryl, sulfonated polystyrene, methyl acrylate-sulfonated styrene copolymer, and combinations comprising at least one of the foregoing.

[0054] The quencher composition can be added in a solid or a liquid form. When in the liquid form, the quencher composition can be added, for example, via an addition system. The addition system can comprise a first drum; a buffer drum; a dosing pump; a filter; an injector, or a combination comprising one or more of the foregoing, where one or both of the first drum and the buffer drum can comprise an agitator and/or a heating system. The quencher and a liquid carrier can be added to the first drum and then added to a buffer drum. From the buffer drum, the liquid quencher composition can be injected to the polymerization system via an injector located in one or more of a polymerization unit, a reactor, a transfer line, a mixer, and an extruder. The pumping of the quencher composition to a dosing pump can be controlled by a main distribution loop, where the addition of the quencher composition can be monitored with a flow meter, either continuously or intermittently. The pumping can further comprise a controller for automated monitoring of the flow meter and adjustment of the amount of the quencher composition to the polymerization unit. The liquid quencher composition can be added to the polycarbonate at a pressure of greater than or equal to 2 bars, specifically, greater than or equal to 3 bars, more specifically, 3 to 100 bar. The liquid quencher composition can likewise be added by spraying the liquid onto a solid PC substrate. The liquid quencher composition can be filtered before it is added to the polymerization system. The quencher composition can be mixed with the polycarbonate for a period of time of greater than or equal to 5 seconds prior to the addition to the polycarbonate of any additives having a reactive OH group or reactive ester group.

[0055] An additive can further be added at one or more locations in the present melt preparation of the polycarbonate. For example, the additive can be added upstream of a polymerization unit, directly into a polymerization unit (for example, at an inlet, in a side feeder, in an outlet, or a combination comprising one or more of the foregoing), downstream of a polymerization unit, in a reactor that is not polymerizing polycarbonate, upstream of an extruder, directly into an extruder (for example, at the throat of the extruder, in a side feeder, in an outlet, or a combination comprising one or more of the foregoing), downstream of an extruder, or a combination comprising one or more of the foregoing. The additive can be added as part of the quencher composition or can be added separately. The additive can be added in a molten state or can be added after an extruded polycarbonate is re-melted. The additive can be filtered prior to being added into the polymerization unit.

[0056] The additive can comprise an impact modifier, a flow modifier, a filler (e.g., a particulate polytetrafluoroethylene (PTFE), glass, carbon, a mineral, or metal), a reinforcing agent (e.g., glass fibers), an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet (UV) agent (such as a UV light stabilizer and a UV absorbing additive), a plasticizer, a lubricant, a release agent (such as a mold release agent (such as glycerol monostearate, pentaerythritol stearate, glycerol tristearate, stearyl stearate, and the like)), an antistatic agent, an antifog agent, an antimicrobial agent, a colorant (e.g., a dye or pigment), a surface effect additive, a radiation stabilizer, a flame retardant, an anti-drip agent (e.g., a PTFE- encapsulated styrene-acrylonitrile copolymer (TSAN)), or a combination comprising one or more of the foregoing. A combination of a heat stabilizer, mold release agent, and ultraviolet light stabilizer can be used. The total amount of the additive composition (other than any impact modifier, filler, or reinforcing agent) can be 0.001 to 10.0 wt , or 0.01 to 5 wt , based on the total weight of the polymer in the polymerized composition.

[0057] The polycarbonate composition can have a light transparency of greater than 90% as determined using 3.2 mm thick samples using ASTM D1003-00, Procedure B using CIE standard illuminant C, with unidirectional viewing. When the quenched composition has such a light transparency, it is herein referred to as an "optical grade" composition.

[0058] The present disclosure is further described in the below embodiments. Embodiment 1 : A method of forming a catalyst mixture comprising: mixing a catalyst compound and one or both of a dihydroxy monomer and a carbonate compound, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound; and optionally directing the catalyst mixture to a melt polymerization unit; and melt polymerizing polycarbonate in the melt polymerization unit to form a polycarbonate; wherein if the catalyst mixture comprises only the dihydroxy monomer, then the method further comprises adding the carbonate compound to the polymerization unit prior to polymerizing, and wherein if the catalyst mixture comprises only the carbonate compound, then the method further comprises adding the dihydroxy monomer to the polymerization unit prior to polymerizing.

[0059] Embodiment 2: The method of Embodiment 1 , wherein the catalyst mixture comprises both the dihydroxy monomer and the carbonate compound.

[0060] Embodiment 3: The method of Embodiment 2, wherein the adding comprises first adding the dihydroxy monomer and the carbonate compound in any order and then adding the catalyst compound.

[0061] Embodiment 4: The method of Embodiment 2, wherein the adding comprises first adding the catalyst compound and then adding the dihydroxy monomer and the carbonate compound in any order.

[0062] Embodiment 5: The method of Embodiment 2, wherein the adding comprises adding one of the dihydroxy monomer and the carbonate compound, adding the catalyst compound, and then adding the other of the dihydroxy monomer and carbonate compound.

[0063] Embodiment 6: The method of Embodiment 1 , wherein the adding comprises adding only one of the dihydroxy monomer and the carbonate compound to the monomer mixing unit and then adding the catalyst compound, wherein the other of the dihydroxy monomer and the carbonate compound that is not added to the monomer mixing unit, is added to the catalyst mixture downstream of a monomer mixing unit.

[0064] Embodiment 7: The method of any of the preceding Embodiments, wherein the melt polymerizing comprises adding a quencher composition comprising a quencher.

[0065] Embodiment 8: The method of Embodiment 7, further comprising mixing the polycarbonate with the quencher composition for a period of time of greater than or equal to 5 seconds prior to the addition to the polycarbonate of any additives having a reactive OH group or a reactive ester group. [0066] Embodiment 9: The method of any of Embodiments 1-9, further comprising adding a reactive additive to the polycarbonate.

[0067] Embodiment 10: The method of Embodiment 9, further comprising adding an unreactive additive to the polycarbonate, wherein the unreactive additive is free of a reactive OH group or reactive ester group.

[0068] Embodiment 11 : The method of any of Embodiments 7-10, wherein the quencher composition comprises the unreactive additive.

[0069] Embodiment 12: The method of any of Embodiments 7-11, wherein the quencher composition comprises 0.1 to 100 wt% quencher.

[0070] Embodiment 13: The method of any of Embodiments 7-12, wherein the quencher composition comprises 10 to 99 wt% quencher.

[0071] Embodiment 14: The method of any of Embodiments 7-13, wherein the quencher composition is a liquid quencher composition; and wherein the melt polymerizing comprises polymerizing the polycarbonate in a series of polymerization units; and wherein the method further comprises adding the liquid quencher composition after one or more of the polymerization units.

[0072] Embodiment 15: The method of any of Embodiments 7-14, wherein the quencher composition comprises 1 to 10 ppm of a sulfonic acid ester, based upon 100 parts of the polycarbonate.

[0073] Embodiment 16: The method of any of Embodiments 7-15, wherein the quencher composition comprises 1 to 10 ppm phosphorous acid, based upon 100 parts of the polycarbonate.

[0074] Embodiment 17: The method of any of Embodiments 7-16, wherein the quencher composition comprises 2 to 5 ppm sulfonic acid ester and 2 to 5 ppm phosphorous acid, based upon 100 parts of the polycarbonate.

[0075] Embodiment 18: The method of any of Embodiments 7-17, wherein the quencher composition comprises n-butyl tosylate.

[0076] Embodiment 19: The method of any of Embodiments 7-18, wherein the quencher composition comprises 1 to 7 ppm quencher, based upon 100 parts of the PC.

[0077] Embodiment 20: The method of any of Embodiments 7-19, wherein the quencher composition comprises 1.5 to 3 ppm quencher, based upon 100 parts of the PC. [0078] Embodiment 21 : The method of any of Embodiments 7-20, wherein the quencher comprises a difunctional compound having an acid or acid ester moiety and an amine moiety.

[0079] Embodiment 22: The method of any of Embodiments 7-21, wherein the quencher composition is a liquid quencher composition.

[0080] Embodiment 23: The method of any of Embodiments 7-22, further comprising adding the quencher composition before adding an additional catalyst.

[0081] Embodiment 24: The method of any of Embodiments 7-23, comprising adding the quencher composition after the further melt polymerizing of the reactants.

[0082] Embodiment 25: The method of any of Embodiments 7-24, wherein the quencher composition comprises a heat stabilizer.

[0083] Embodiment 26: The method of any of Embodiments 7-25, further comprising introducing an additive after adding of the quencher composition, and wherein the additive optionally comprises a release agent and a UV agent.

[0084] Embodiment 27: The method of Embodiment 26, further comprising filtering the additive prior to introducing the additive to the polycarbonate.

[0085] Embodiment 28: The method of any of Embodiments 7-27, wherein adding a quencher composition comprises spraying the quencher composition onto the polycarbonate.

[0086] Embodiment 29: The method of any of Embodiments 7-28, further comprising adding the quencher to a quencher vessel to form a quencher composition prior to adding the quencher composition.

[0087] Embodiment 30: The method of Embodiment 29, further comprising adding a liquid carrier to the quencher vessel.

[0088] Embodiment 31 : The method of Embodiment 29, wherein the quencher composition is a melt quencher and is free of a liquid carrier.

[0089] Embodiment 32: The method of any of Embodiments 7-31, further comprising mixing the quencher composition prior to adding the quencher composition.

[0090] Embodiment 33: The method of any of Embodiments 7-32, further comprising filtering the quencher composition prior to adding.

[0091] Embodiment 34: The method of any of Embodiments 7-33, wherein adding the quencher composition occurs at a pressure of greater than or equal to 2 bars.

[0092] Embodiment 35: The method of any of Embodiments 7-34, wherein adding the quencher composition occurs at a pressure of greater than or equal to 3 bars. [0093] Embodiment 36: The method of any of Embodiments 7-35, wherein adding the quencher composition occurs at a pressure of 3 to 100 bars.

[0094] Embodiment 37: The method of any of Embodiments 1-36, further comprising directing the polycarbonate to an extruder.

[0095] Embodiment 38: The method of any of Embodiments 1-38, wherein a solid quencher is added to an extruder.

[0096] Embodiment 39: The method of any of Embodiments 7-38, wherein the quenching composition includes a compound of formula: R_a ¾ R_c N⁺-A-SC>3^~, wherein R_a and R_b are each independently hydrogen, Q-C₁2 alkyl, Q-C₁2 aryl, or Ci-Qs alkylaryl; R_c is a hydrogen; R_a, R_b, singly or in combination form a heterocyclic ring structure with N; and A is C₁-C₁2 alkyl, C₁-C₁2 aryl, or Ci-Cis alkylaryl.

[0097] Embodiment 40: The method of any of the preceding Embodiments, further comprising adding an antioxidant, a release agent, a UV agent, a flame retardant, or a combination comprising one or more of the foregoing.

[0098] Embodiment 41 : The method of any of the preceding Embodiments, wherein the method is a batch process.

[0099] Embodiment 42: The method of any of the preceding Embodiments, wherein the catalyst compound comprises tetraphenyl phosphonium phenoxide (TPPP), tetraphenyl phosphonium acetate (TPPA), or a combination comprising one or more of the foregoing.

[0100] Embodiment 43: The method of any of the preceding Embodiments, wherein the catalyst compound comprises tetrabutyl phosphonium acetate (TBPA), tetraphenyl phosphonium phenoxide (TPPP), tetraphenyl phosphonium acetate (TPPA), or a combination comprising one or more of the foregoing.

[0101] Embodiment 44: The method of Embodiment 43, wherein the catalyst compound comprises tetraphenyl phosphonium phenoxide.

[0102] Embodiment 45: The method of any of the preceding Embodiments, comprising adding no alkali catalyst comprising a source of alkali ions or alkaline earth ions.

[0103] Embodiment 46: The method of any of the preceding Embodiments, comprising adding no alkali metal hydroxides and no alkaline earth hydroxides.

[0104] Embodiment 47: The method of any of the preceding Embodiments, comprising adding no salts of carboxylic acids, derivatives of ethylene diamine tetra acetic acid (EDTA). [0105] Embodiment 48: The method of any of the preceding Embodiments, comprising adding no Cs₂C0₃, NaHC0₃, Na₂C0₃, NaH₂P0₃, NaH₂P0₄, Na₂HP0₃, KH₂P0₄, CsH₂P0₄, Cs₂HP0₄, NaKHP0₄, CsNaHP0₄, or CsKHP0₄.

[0106] Embodiment 49: The method of any of Embodiments 1-44, wherein the catalyst compound comprises a metal compound, wherein the metal comprises at least one of sodium, potassium, cesium; wherein if the metal compound comprises sodium sulfate, the amount of sodium is 0 to 1,690 ppm; if the metal compound comprises cesium sulfate, the amount of cesium is 0 to 275 ppm; if the metal compound comprises sodium hydroxide, the amount of sodium is 0 to 35 ppm; if the metal compound comprises potassium hydroxide, the amount of potassium is 0 to 50 ppm; if the metal compound comprises cesium hydroxide, the amount of cesium is 0 to 140 ppm all based on the weight of the catalyst compound.

[0107] Embodiment 50: The method of any of the preceding Embodiments, wherein the mixing occurs at a temperature of 100 to 250°C. Embodiment 51 : The method of any of the preceding Embodiments, wherein the mixing occurs at a temperature of 150 to 200°C. Embodiment 52: The method of any of the preceding Embodiments, wherein the mixing occurs at a temperature of 165 to 185°C.

[0108] Embodiment 53: The method of any of the preceding Embodiments, wherein the mixing occurs at atmospheric pressure.

[0109] Embodiment 54: The method of any of the preceding Embodiments, wherein the method comprises adding no alkali catalyst.

[0110] Embodiment 55: The method of any of Embodiments 1-53, wherein further comprising the step of adding an alkali catalyst.

[0111] Embodiment 56: The method of any of the preceding Embodiments, wherein the melt polycarbonate has a branching of less than or equal to 100 ppm based on the total weight of the melt polycarbonate.

[0112] Embodiment 57: The method of any of the preceding Embodiments, wherein the melt polymerizing comprises reacting the reactants in a wire-wetting fall polymerizer.

[0113] Embodiment 58: The method of any of the preceding Embodiments, wherein the melt polymerizing comprises reacting the reactants in the presence of the catalyst composition, adding additional catalyst and further melt polymerizing the reactants.

[0114] Embodiment 59: The method of any of Embodiments 1-58, wherein the melt polymerizing comprises oligomerizing at an oligomerization temperature of 100°C to 280°C, and polymerizing at a polymerization temperature of 250°C to 310°C, and wherein the oligomerization temperature is less than the polymerization temperature.

[0115] Embodiment 60: The method of Embodiment 59, wherein the oligomerizing is at an oligomerization pressure of greater than 100 mbara.

[0116] Embodiment 61 : The method of any of Embodiments 59-60, wherein the oligomerizing comprising a first oligomerization at a first oligomerization temperature of 150°C to 260°C at a first oligomerization pressure of greater than or equal to 100 mbara; and a subsequent oligomerization at a second oligomerization temperature of 230°C to 280°C, and a second oligomerization pressure of 15 to 90 mbara.

[0117] Embodiment 62: The method of any of Embodiments 59-61, wherein the polymerizing comprises a first polymerization at a first polymerization temperature of 260°C to 310°C at a polymerization pressure of 1 to 10 mbara; and a subsequent polymerization at a second polymerization temperature of 260°C to 300°C, and a second polymerization pressure of less than or equal to 5 mbara.

[0118] Embodiment 63: The method of Embodiment 62, wherein the first polymerization temperature and the second polymerization temperature is 260°C to 285 °C.

[0119] Embodiment 64: The method of any of Embodiments 59-63, wherein the first polymerization temperature and the second polymerization temperature is 270°C to 280°C.

[0120] Embodiment 65: The method of any of Embodiments 59-64, wherein the polymerizing is in one or more wire wetting polymerizers and the polymerization temperature is 200°C to 300°C, and the polymerization pressure is less than or equal to 4 mbara.

[0121] Embodiment 66: The method of Embodiment 65, wherein the polymerization temperature is 250°C to 280°C.

[0122] Embodiment 67: The method of any of Embodiments 49-66, wherein the polymerizing comprises a first polymerization unit and a second unit, wherein a

polycarbonate produced in the first polymerization unit has a number average molecular weight of 20,000 to 50,000 Daltons.

[0123] Embodiment 68: The method of Embodiment 67, wherein the polycarbonate increases its molecular weight by less than or equal to 10 wt% in the second unit and wherein the method further comprises devolatizing in the second unit.

[0124] Embodiment 69: The method of any of the preceding Embodiments, wherein the dihydroxy monomer comprises bisphenol A. [0125] Embodiment 70: The method of any of the preceding Embodiments, wherein the carbonate compound comprises a diaryl carbonate.

[0126] Embodiment 71 : The method of any of the preceding Embodiments, further comprising devolatizing the polycarbonate.

[0127] Embodiment 72: The method of Embodiment 71, wherein the devolatizing occurs in one or more of an extruder, a polymerization unit, a devolatization unit.

[0128] Embodiment 73: The method of any of Embodiments 71-72, wherein the devolatizing occurs after quenching.

[0129] Embodiment 64: The method of any of the preceding Embodiments, wherein the melt polymerization comprises a section of parallel polymerization.

[0130] Embodiment 65: The method of Embodiment 64, wherein the section of parallel polymerization comprises: polymerizing PC in a series of oligomerization units; splitting a stream exiting the oligomerization units into a stream A and stream B, directing stream A to a polymerization unit A and directing stream B to a polymerization unit B.

[0131] Embodiment 66: The method of Embodiment 64, wherein the section of parallel polymerization comprises: polymerizing PC in a series of oligomerization units; splitting a stream exiting an oligomerization unit into a stream A and a stream B, directing stream A to a polymerization unit A and directing stream B to a polymerization unit B.

[0132] Embodiment 67: The method of Embodiment 64, wherein the section of parallel polymerization oligomerization units, then polymerizing in a series of

polymerization units, splitting a stream exiting a final polymerization unit into a stream A and a stream B, directing stream A to an extruder A and directing stream B to an extruder B or wherein the section of parallel polymerization comprises: polymerizing PC in a series of oligomerization units, then polymerizing in a series of two polymerization units; splitting a stream exiting a first polymerization unit into a stream A and a stream B, directing stream A to a second polymerization unit A and directing stream B to a second polymerization unit B.

[0133] Embodiment 68: The method of any of the preceding Embodiments, wherein forming of a catalyst mixture comprises adding the dihydroxy compound, the carbonate compound, and the catalyst compound to form the catalyst mixture in any order; wherein the catalyst compound is not exposed to a solvent carrier level of greater than 500 ppm based on the total weight of the catalyst compound, wherein the solvent carrier comprises one or both of water and an alkyl alcohol. The alkyl alcohol can comprise methanol, ethanol, propanol, butanol, and the like or a combination comprising one or more of the foregoing. [0134] Embodiment 69: The method of any of Embodiments 1-4 and 7-68, wherein the adding comprises adding the dihydroxy compound, adding the carbonate compound, reducing the water and/or an alkyl alcohol level to a reduced level of less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound, and adding the catalyst compound after the reducing.

[0135] Embodiment 70: The method of any of the preceding Embodiments, wherein the adding the dihydroxy compound comprises adding a solid dihydroxy to a molten carbonate compound.

[0136] Embodiment 71 : The method of any of the preceding Embodiments, wherein one or both of the carbonate compound and the dihydroxy compound has a water and/or an alkyl alcohol level of less than or equal to 450 ppm, specifically, less than or equal to 260 ppm, more specifically, less than or equal to 90 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm, specifically, less than or equal to 240 ppm, more specifically, less than or equal to 80 ppm based on the total weight of the dihydroxy compound prior to adding.

[0137] Embodiment 72: The method of any of the preceding Embodiments, wherein the adding the dihydroxy compound and the carbonate compound occurs at a temperature greater than or equal to the melting temperature of the carbonate compound.

[0138] Embodiment 73: The method of any of the preceding Embodiments, wherein the adding occurs under an inert atmosphere.

[0139] Embodiment 74: The method of any of the preceding Embodiments, comprising the directing the catalyst mixture to a melt polymerization unit; and melt polymerizing PC in the melt polymerization unit to form a PC; wherein if the catalyst mixture comprises only the dihydroxy monomer, then the method further comprises adding the carbonate compound to the polymerization unit prior to polymerizing, and wherein if the catalyst mixture comprises only the carbonate compound, then the method further comprises adding the dihydroxy monomer to the polymerization unit prior to polymerizing.

[0140] Embodiment 75: The method of any of the preceding Embodiments, wherein the carbonate compound is free of an activated carbonate compound. [0141] Embodiment 76: The method of any of the preceding Embodiments, wherein the carbonate compound is free of bis(4-nitrophenyl)carbonate, bis(2-chlorophenyl) carbonate, bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate, bis(4-methylcarboxyl phenyl) carbonate, bis(2-acetylphenyl) carboxylate, and bis(4-acetylphenyl) carboxylate.

[0142] Embodiment 77: The method of any of the preceding Embodiments, wherein the carbonate compound is free of bis(methyl salicyl)carbonate.

[0143] Embodiment 78: The method of any of the preceding Embodiments, wherein the melt polymerizing occurs in the presence of less than or equal to 1 ppm of an activated carbonate compound.

[0144] Embodiment 79: A method of controlling endcapping during the formation of melt polycarbonate, comprising forming the catalyst mixture of any of the preceding Embodiments; adjusting a water and/or an alkyl alcohol level of the catalyst mixture; and melt polymerizing to form the polycarbonate.

[0145] Embodiment 80: The method of Embodiment 79, further comprising determining a desired endcapping level, wherein the water and/or an alkyl alcohol level is adjusted to attain the desired endcapping level.

[0146] Embodiment 81 : A polycarbonate formed from the method of any of the preceding Embodiments.

[0147] Embodiment 82: The polycarbonate of any of Embodiments 79-81, wherein the polycarbonate has an endcapping level of greater than or equal to 60 mol , more specifically, greater than or equal to 80 mol , more specifically, greater than or equal to 90 mol wherein the endcapping is the molar ratio in percent of phenolic end groups based on the total moles of end groups.

[0148] As used herein, when referring to "reactive" or a "reactive group", e.g., having a reactive OH^" group or a reactive ester group, the reactivity is with respect to polycarbonate. The invention may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present invention.

[0149] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of "up to 25 wt , or, more specifically, 5 to 20 wt ", is inclusive of the endpoints and all intermediate values of the ranges of "5 to 25 wt ," etc.). "Combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to denote one element from another. The terms "a" and "an" and "the" herein 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. The suffix "(s)" as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the film(s) includes one or more films). Reference throughout the specification to "one embodiment," "another embodiment," "an embodiment," and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. Disclosure of a narrower range or more specific group in addition to a broader range is not a disclaimer of the broader range or larger group.

[0150] While particular embodiments 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.

[0151] This application claims the benefit of European Application No. 14382471 filed 25 November 2014. The related application is incorporated herein by reference.

[0152] I/we claim:

Claims

1. A method of forming a catalyst mixture comprising:

adding a dihydroxy compound, a carbonate compound, and a catalyst compound to form the catalyst mixture in any order, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound;

wherein in the catalyst mixture, the catalyst compound is exposed to a water and/or an alkyl alcohol level of less than or equal to 250 ppm based on the total weight of the catalyst mixture.

2. The method of Claim 1 , wherein the adding comprises adding the dihydroxy compound, adding the carbonate compound, reducing the water and/or an alkyl alcohol level to a reduced level of less than or equal to 450 ppm based on the total weight of the carbonate compound and/or less than or equal to 400 ppm based on the total weight of the dihydroxy compound; and adding the catalyst compound.

3. The method of any of the preceding claims, wherein the adding the dihydroxy compound comprises adding a solid dihydroxy compound to a molten carbonate compound.

4. The method of any of the preceding claims, wherein the carbonate compound comprises less than or equal to 450 ppm of water and/or an alkyl alcohol based on the total weight of the carbonate compound and/or the dihydroxy compound comprises less than or equal to 400 ppm of water and/or an alkyl alcohol based on the total weight of the dihydroxy compound prior to adding.

5. The method of any of the preceding claims, wherein the adding occurs under an inert atmosphere.

6. The method of any of the preceding claims, wherein the catalyst compound comprises tetraphenyl phosphonium phenoxide.

7. The method of any of the preceding claims, wherein the catalyst compound comprises a metal compound, wherein the metal comprises at least one of sodium, potassium, cesium; wherein if the metal compound comprises sodium sulfate, the amount of sodium is 0 to 1,690 ppm; if the metal compound comprises cesium sulfate, the amount of cesium is 0 to 275 ppm; if the metal compound comprises sodium hydroxide, the amount of sodium is 0 to 35 ppm; if the metal compound comprises potassium hydroxide, the amount of potassium is 0 to 50 ppm; if the metal compound comprises cesium hydroxide, the amount of cesium is 0 to 140 ppm all based on the weight of the catalyst compound.

8. The method of any of the preceding claims, wherein the mixing occurs at a temperature of 100 to 250°C and at atmospheric pressure.

9. The method of any of the preceding claims, wherein the carbonate compound is free of bismethyl salicyl carbonate.

10. A method of polymerizing polycarbonate comprising:

directing the catalyst mixture of any of the preceding claims to a melt polymerization unit; and

melt polymerizing to form the polycarbonate.

11. A method of controlling endcapping during the formation of melt polycarbonate, comprising:

adding a dihydroxy compound, a carbonate compound, and a catalyst compound to form the catalyst mixture, wherein the catalyst compound comprises one or both of a quaternary ammonium compound and a quaternary phosphonium compound;

adjusting a water and/or an alkyl alcohol level of the catalyst mixture; and melt polymerizing the dihydroxy compound and the carbonate compound in the presence of the catalyst compound to form the polycarbonate.

12. The method of Claim 11, further comprising adding a quencher composition to the polycarbonate at a pressure of greater than or equal to 2 bars, and mixing the quencher composition with the polycarbonate for a period of time of greater than or equal to 5 seconds prior to the addition to the polycarbonate of any additives having a reactive OH group or reactive ester group.

13. The method of any of Claims 11-12, further comprising determining a desired endcapping level, wherein the water and/or an alkyl alcohol level is adjusted to attain the desired endcapping level.

14. A polycarbonate formed from the method of any of Claims 11-13.

15. The polycarbonate of Claim 14, wherein the polycarbonate has an endcapping level of greater than or equal to 60 mol , wherein the endcapping is the molar ratio in percent of phenolic end groups based on the total moles of end groups.