Alkaline hydrolysis of polyethylene terephthalate using phase transfer catalysis

Abstract

A method for hydrolysing / depolymerising polymers comprising polyethylene terephthalate units and / or poly(bisphenol A carbonate) units is disclosed herein, said method involving the use of phase transfer catalysts and alkaline reaction conditions.

Description

Alkaline Hydrolysis of Polyethylene Terephthalate Using Phase Transfer Catalysis Field

[0001] The present invention is concerned with alkaline hydrolysis of polymers, such as polyethylene terephthalate, using phase transfer catalysis. BACKGROUND

[0002] It has been estimated that from 1950 to 2015, 6.3 x 1012kg of plastics have been synthesised – with a recycle rate of just ca. 9%. It has further been estimated, that without intervention, by 205012 x 1013kg of these polymers will either be in landfill or out polluting the natural world, therefore (until replacement of traditional plastics with sustainable materials is widespread) improvement in both the rate and efficiency of recycling is needed to reduce both the dependence on oil-derived virgin plastic and the contribution its synthesis / disposal makes to the current climatological and ecological emergency.

[0003] Poly(ethylene terephthalate) (PET) polyester is a major constituent in certain beverage bottles, textile fibres and food tray / pharmaceutical packaging which in 2021 accounted for 12% of worldwide solid waste. Of the commonly bulk-manufactured plastics, PET has the highest greenhouse gas (GHG) emissions associated with its production (up to 4.5 kg GHG / kg PET) yet is one of the most amenable to various ‘recycling’ methodologies - which can broadly be categorised as either incineration, mechanical- or chemical recycling. Incineration solves the landfill problem and can recover energy from the materials but has been determined after a recent study by the European Commission’s Joint Research Centre to be less preferable from a climate change impact perspective. Mechanical recycling is operationally more facile yet amplifies existing degradation and produces recycled PET of lower value and quality. Chemical recycling via depolymerisation requires efficient process chemistry on large scales (frequently at high temperatures), however it can produce pure monomers which can be repolymerised to pristine PET for any application – thereby reducing reliance on fossil fuel-derived virgin PET. In addition, in the case of PET, a recent analysis found that CO2 emission savings at end of life treatment are considerably lower for chemical recycling than for mechanical. Chemical recycling methodologies include (inter alia) aminolysis, alcoholysis, glycolysis and hydrolysis.

[0004] Alkaline hydrolysis of PET waste generally involves using a metal hydroxide catalyst, such as sodium hydroxide or potassium hydroxide, with a concentration between 4 and 20 % w / w at elevated temperature and pressure (e.g.225˚C, and 17 atm). The product of alkaline hydrolysis using sodium hydroxide of PET is disodium terephthalate and ethylene glycol.Treatment of the disodium terephthalate with acid results in the formation of terephthalic acid (TPA).

[0005] GB822834 describes a method of processing waste PET by hydrolysing with an alkali metal hydroxide solution at about 100˚C, for about 2 hours using 10% solution of sodium hydroxide in a weight ratio to the polyester of 20:1 to obtain a maximum salting-out effect. The precipitated salt is filtered from the solution and additional sodium hydroxide added to the filtrate which may be used for further hydrolyses. Ethylene glycol, which remains in the filtrate, may be distilled out when its concentration has been increased by repeated use of the filtrate. The solvent used may be water, an alcohol or an aqueous alcohol, e.g.50%. In a modification of the process the reaction is carried out in methanol under pressure in a single stage in the presence of 0.7% to 2% alkali metal hydroxide referred to the polyester, to give a mixture of monomethyl terephthalate and dimethyl terephthalate. The alkali metal terephthalate may be converted to the free acid or its esters by known methods. Examples are given using sodium and potassium hydroxide and water, methanol, ethanol and aqueous methanol.

[0006] WO2017087752A1 describes a process for chemically recycling PET which utilizes a microwave absorber to optimize glycolytic depolymerization of PET via microwave irradiation. The method of chemically degrading PET to its reactive intermediate, bis(2- hydroxyethyl) terephthalate (BHET), is carried out by: (a) combining PET with ethylene glycol and a catalytic system comprising a catalyst and a microwave absorber to produce a heterogeneous reaction mixture; and then (b) heating by microwave irradiating the reaction mixture to a temperature sufficient to produce a reaction product comprising BHET. The BHET monomer then can be purified and re-polymerized to form new, virgin PET.

[0007] US20050096482A1 describes a method of depolymerizing polyethylene terephthalate, and a method of manufacturing a polyester resin. When heating, melting and depolymerizing polyethylene terephthalate to be recycled, the heating, melting and depolymerization reaction of the polyethylene terephthalate to be recycled are carried out all at once using one or a plurality of extruders or using an extruder and a reactor provided at an outlet of the extruder. When manufacturing a polyester resin, the reactants are irradiated with microwaves, thus promoting the heating of the reactants, and promoting the esterification reaction.

[0008] A particularly attractive potential PET recycling methodology is alkaline hydrolysis in the presence of a phase transfer catalyst (PTC). This has the advantages of lower reaction temperatures (typically 80-100˚C) than those required by neutral hydrolysis and less contamination by oligomers or decomposition of ethylene glycol using either neutral or acidic hydrolysis respectively.

[0009] While phase transfer catalysis of alkaline PET hydrolysis to form (after acidic workup) terephthalic acid is known, the PTC characteristics required to bring about efficient promotion of the process are poorly understood. Attempts to elucidate a consensus model of the contributors to catalyst activity are confounded by studies using different catalysts, loadings (1- 100 mol%), PET sources, particle sizes, temperatures, stirring speeds, NaOH stoichiometry, NaOH concentrations, microwave-radiation and ultrasound.

[0010] Kosmidis et al. (Macromol. Mater. Eng.2001, 286, 640–647) describe alkaline hydrolysis of PET using trioctylmethylammonium bromide as phase transfer catalyst with sodium hydroxide. Depolymerization reactions were carried out using 1.5 litres of sodium hydroxide (5- 15 wt%) at a temperature of 70-95˚C, and a concentration of PET in the range of from 7.6 g / L to 38 g / L. It was observed that reaction yield was higher at lower concentrations of PET. The PET particle size tested ranged from less than 0.71 mm to 2 mm, with smaller particle size resulting in higher yield and shorter reaction times.

[0011] Barredo et al. (J. Environ. Chem. Eng.2023, 11, 109823) describe the alkaline hydrolysis of PET using tributylhexyadecylphosphonium bromide as phase transfer catalyst in the presence of sodium hydroxide. The effect of a wide number of operating variables (temperature, concentration of the quaternary salt, particle size and stirring rate) was studied. Optimal conditions resulted in PET conversion (99.9%) and TPA yield (93.5%) has been established after 4 h of reaction, under the following operating conditions: catalyst ratio TBHDPB:PET= 0.2:1; T = 100 ºC; particle size= 1–1.4 mm and stirring rate= 525 rpm. A PET concentration of 100 g / L was employed (66.6 g PET flakes in 666.6g water).

[0012] López-Fonseca et al. (WIT Trans. Ecol. Environ., 2008, 109, 511) describe chemical recycling of PET by alkaline hydrolysis in the presence of quaternary phosphonium and ammonium salts as phase transfer catalysts. Out of nine phase transfer catalysts investigated six of the catalysts were totally inactive in the reaction with conversion values being virtually identical to those recorded in the absence of phase transfer catalyst. The catalysts of choice identified by López-Fonseca et al. were tributylhexadecyl phosphonium bromide and tetraoctyl phosphonium bromide, which were reported to attain PET conversion values of 84% and 75% respectively. For 10 g of PET flakes depolymerised in 150 ml of a 6.7% aqueous sodium hydroxide solution (NaOH:PET molar ratio = 5.76) at 60, 70, 80, 90 and 100 ºC, it was found that the amount of PET flakes depolymerised increased with temperature as a function of reaction time, with the higher PET conversion observed at higher temperatures. The reaction conditions tested involved a PET concentration of 67 g / L (10 g PET per 150 mL water).

[0013] Paliwal et al. (Mungray, Polym. Degrad. Stab., 2013, 98, 2094) report on ultrasound assisted alkaline hydrolysis of poly(ethylene terephthalate) in the presence of tetrabutyl ammonium iodide (TBAI) as phase transfer catalyst. A reduction in reaction time was observed and high yield was achieved for ultrasound assisted reactions. Paliwal et al. employedPET flakes ground to a particle size of from 0.2 to 0.5 mm. The molecular weight of the PET used was approximately 30,000 with polydispersity index 2. The reaction conditions tested involved 50 mL water, 0.09 g of TBAI catalyst and 3 g of PET ground flakes, with 5 g of NaOH, thereby providing an NaOH:PET ratio of 1.67:1 w / w, and a catalyst:PET ratio of 0.03:1 w / w. These conditions were tested with and without ultrasound, with a reaction temperature of 90˚C. The disodium terephthalate produced was acidified using concentrated H2SO4. It was observed, that the rate of the hydrolysis reaction increased by the use of ultrasound. It was further observed that as the amount of TBAI was increased per unit weight of PET, the rate of conversion increased. 10% (w / w) NaOH concentration, TBAI:PET ratio 0.03:1, and a temperature of 90˚C was reported as being the optimal conditions for ultrasound assisted alkaline hydrolysis of PET. The reaction conditions tested involved a PET concentration of 60 g / L (3 g PET per 50 mL water).

[0014] Parikh and co-workers (J. Das, A. B. Halgeri, V. Sahu and P. A. Parikh, Ind. J. Chem. Technol., 2007, 14, 173) reported that benzalkonium chloride outperformed aliphatic (albeit relatively hydrophilic) tetraalkylammonium salts in the alkaline hydrolysis of PET. Parikh and co-workers carried out PET depolymerization with a PET starting concentration of 10 g in 100 mL of water, i.e. a PET starting concentration of 100 g / L. The PET particle size was <0.6 mm.

[0015] In non-PET hydrolysis systems Herriot et al. (A. W. Herriott and D. Picker, J. Am. Chem. Soc., 1975, 97, 2345) found that larger symmetrical cations outperformed catalysts with one long chain in an SN2 reaction in benzene / water catalysed by ammonium and phosphonium PTCs, while earlier Starks (J. Am. Chem. Soc., 1971, 93, 195) warned that ammonium PTCs were poor overall promoters of alkaline ester hydrolysis if the ester incorporated a long chain, including when using poly(methyl acrylate) as a substrate.

[0016] Poly(bisphenol A carbonate) (BPA-PC) is a high-strength hydrophobic thermoplastic used in (inter alia) safety goggles, headlights, computer casings, compact disks (CDs), window panes and safety paraphernalia. Although controversial, there is concern regarding BPA-PC / BPA-PC-waste focused on its monomer constituent bis-phenol A as an endocrine disrupting agent. Advances in the chemical recycling of BPA-PC has proceeded along similar lines to those associated with PET, with a major difference: BPA-PC is considerably more susceptible to the action of organic co-solvents. PET has been blended with BPA-PC to improve its resistance to organic solvents, while blending with BPA-PC can improve the impact strength and dimensional stability of PET. To date, there has been considerable focus on solvent-assisted hydrolytic depolymerisation of BPA-PC, where often completely recalcitrant base-mediated hydrolysis in water proceeds upon the addition of an organic cosolvent. In the absence of cosolvents, hydrolysis of BPA-PC is difficult and, in addition, the product monomer BPA is prone to decomposition at high temperatures.

[0017] Achillas and co-workers (J. Hazard. Mater.2012, 241, 137) utilized microwave radiation to degrade waste BPA-PC in the presence of 1-hexadecyltrimethylammonium bromideas a phase transfer catalyst via alkaline hydrolysis (NaOH, 10% w / v). After 10 min at 150 ˚C (pressure = 4 bar) the polymer was 30% degraded, which increased to 95% degradation at 160 ˚C. No yield / characterization of BPA was recorded and methanol was required to solubilize BPA and its degradation products isopropenyl phenol / t-butyl phenol / phenol so they could be separated from unreacted BPA-PC.

[0018] BPA-PC is often blended with PET to enhance its properties. It would be desirable to have efficient methods for recycling mixed plastics.

[0019] Dove and Sardon and co-workers (C. Jehanno, J. Demarteau, D. Mantione, M. C. Arno, F. Ruipérez, J. L. Hedrick, A. P. Dove, H. Sardon, Angew. Chem. Int. Ed.2021, 60, 6710) describe an elegant organocatalytic solution for the selective depolymerisation of BPA-PC in the presence PET and trimethylolpropane allyl ether diol at 130 ˚C in under 1 h. The unreacted PET could be then removed by filtration and depolymerised at a higher temperature.

[0020] Wang and coworkers (R. Yang, G. Xu, B. Dong, X. Guo, Q. Wang, ACS Sustainable Chem. Eng.2022, 10, 9860) developed an efficient ‘one pot’ depolymerisation of BPA-PC-PET by Zn(HMDS)2-catalysed methanolysis for 15 h at 100 ˚C involving complete destruction of both plastics followed by selective monomer isolation: washing with cold methanol allowed bisphenol A (97%) to be separated from the soluble dimethyl terephthalate PET-derived methanolysed product (90%, which could be concentrated in vacuo) by filtration.

[0021] It would be desirable to provide efficient methods for alkaline hydrolysis of polymers, particularly polyesters such as those polyethylene terephthalate or polycarbonate, such as poly(bisphenol A carbonate). In particular, it would be desirable to provide efficient methods for alkaline hydrolysis of polymers including polyethylene terephthalate units, which is environmentally more efficient, and which can be effectively carried out with polyethylene terephthalate flakes which have not been ground to sub-millimetre particle size, preferably where the method is suitable for depolymerizing PET flakes of larger size e.g. circa 5 mm squares, which is consistent with output from mechanical PET recycling facilities, as well as for depolymerizing smaller sized PET particles. In addition, it would be desirable to provide a method for alkaline hydrolysis of polymers including PET units, such as PET, which has less water waste than prior art methods. SUMMARY

[0022] The present invention provides methods for hydrolysing / depolymerising polymers comprising polyethylene terephthalate units, such as polyethylene terephthalate.

[0023] In one aspect, the present invention provides, a method for hydrolysing polyethylene terephthalate comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3 aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

[0024] Suitably, together R1, R2, R3and R4comprise 14 to 36 carbon atoms, suitably, 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

[0025] Optionally, each of R1and R2are independently C1-C3 alkyl. Suitably, each of R1and R2are C1alkyl, preferably methyl.

[0026] Each of R3and R4may be independently selected from C6-C12alkyl.

[0027] R3and R4may be the same.

[0028] R3and R4may be C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10 alkyl, optionally, R3and R4are selected from hexyl, heptyl, octyl, nonyl or decyl.

[0029] Suitably, R1and R2are methyl.

[0030] R1and R2may be methyl and R3and R4may be heptyl, octyl, nonyl or decyl.

[0031] A1- may be selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-.

[0032] The base is suitably an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

[0033] Optionally, the base is an alkali metal hydroxide, such as sodium hydroxide.

[0034] Optionally, the base and water form an alkaline solution having a concentration of from 40% w / v to 70% w / v, such as from 45% w / v to 65% w / v.

[0035] The catalyst may be employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

[0036] The method may further comprise a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0037] The dry weight ratio of base to polyethylene terephthalate may be in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0038] The step of combining poly(ethylene terephthalate), water, base, and a catalyst, may comprise combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, suitably from 250 to 650 g / L. The step of combining poly(ethylene terephthalate), water, base, and a catalyst, may comprise combining polyethylene terephthalate with water in a concentration of 80 to 250 g / L, preferably in a concentration of 100 to 250 g / L, optionally in a concentration of 150 to 250 g / L.

[0039] The base may be present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

[0040] Suitably, the catalyst may be selected from:wherein A- is Br- or Cl-.

[0041] Suitably, the method for hydrolysing polyethylene terephthalate comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C.

[0042] Suitably, the method for hydrolysing polyethylene terephthalate is conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0043] Suitably, the method for hydrolysing polyethylene terephthalate involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes.

[0044] In one aspect, the present invention provides a method for hydrolysing polyethylene terephthalate comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1is N or P, wherein A1- is an anion,wherein each of R1and R2is independently selected from C1-C3 aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms; or Formula (II), wherein X3 is N, and A3- is an anion, wherein Raand Rbare each independently selected from C2-C8aliphatic, wherein Rcis selected from C1-C8aliphatic or C6-C20aryl, and wherein Rdis C6-C20aryl, or wherein Rcand Rdtogether form a ring structure having one or more C5-C10 aryl substituents, and wherein a catalyst of formula (II) comprises at least 18 carbon atoms.

[0045] Optionally, a catalyst of formula II comprises from 18 to 36 carbon atoms, such as from 18 to 30 carbon atoms, optionally from 18 to 26 carbon atoms.

[0046] Optionally, A3- is selected from the group comprising: Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-. is a phase transfer catalyst of formula (I):.

[0048] Each of R1and R2may independently be C1-C3alkyl. For example, each of R1and R2may be C1 alkyl, preferably methyl.

[0049] Each of R3and R4may independently be selected from C6-C12 alkyl.

[0050] Optionally, R3and R4are the same, (i.e. R3= R4).

[0051] R3and R4may be C6 alkyl, C7 alkyl or C8 alkyl. Optionally, each of R3and R4is selected from hexyl, heptyl, or octyl.

[0052] Optionally, R1and R2are methyl, and each of R3and R4is independently selected from heptyl or octyl, preferably, wherein R3and R4are each heptyl.

[0053] Suitably, R1and R2are methyl, and each of R3and R4is heptyl.

[0054] Optionally, A1- is selected from the group comprising: Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-.

[0055] Preferably A1- is I-, Cl- or Br-.

[0056] In one embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is hexyl, and A1- is I-. (Compound 16)

[0057] In a preferred embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is heptyl, and A1- is Br-. (Compound 17)

[0058] Suitably, the catalyst has the structure:

[0059] In one embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is hexyl, and A1- is I-. (Compound 16).

[0060] In a preferred embodiment, X1is N, each of R1and R2is methyl, each of R3and R4is heptyl, and A1- is Br-. (Compound 17).

[0061] Suitably, the catalyst has the structure:and CF3C(O)O-.

[0062] Suitably, the catalyst has the structure:and CF3C(O)O-.

[0063] The catalyst may be a phase transfer catalyst of formula (I):.

[0064] In a preferred embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is octyl, and A1- is Br-. (Compound 18).

[0065] In another preferred embodiment, X1is N, each of R1and R2is methyl, each of R3and R4is nonyl, and A1- is Br-. (Compound 19).

[0066] In another embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is undecyl, and A1- is Br-. (Compound 20).

[0067] In another embodiment, X1is N, each of R1and R2is methyl, each of R3and R4is dodecyl, and A1- is Br-. (Compound 21).

[0068] In another embodiment, X1 is N, each of R1and R2is methyl, each of R3and R4is heptyl, and A1- is I-. (Compound 52)

[0069] In another embodiment, the catalyst has the structure: (Compound 52).

[0070] In a preferred embodiment, X1is N, each of R1and R2is methyl, each of R3and R4is octyl, and A1- is Cl-. (Compound 53).

[0071] In a preferred embodiment, the catalyst has the structure: (Compound 53)

[0073] Each of Raand Rbmay independently be selected from C2 to C6 aliphatic, optionally, C1 to C6 alkyl.

[0074] Optionally, at least two of Ra, Rband Rcare the same.

[0075] Suitably, at least two of Ra, Rband Rcare C4-C6aliphatic, optionally, C4-C6alkyl, further optionally, butyl, pentyl or hexyl.

[0076] Suitably, Rdis C6-C12 aryl. For example, Rdmay be selected from phenyl, biphenyl and naphthyl.

[0077] Raand Rbmay be butyl, and Rdmay be phenyl or biphenyl.

[0078] Rcmay be butyl.

[0079] Optionally, Rcis butyl and Rdis biphenyl.

[0080] In some embodiments, Rcand Rdare each independently C6-C12aryl, optionally, selected from phenyl, naphthyl or biphenyl.

[0081] Suitably, Raand Rbare each independently C4-C6 alkyl, optionally, selected from butyl, pentyl or hexyl.

[0082] For example, Raand Rbmay each be independently C4-C6alkyl, optionally, selected from butyl, pentyl or hexyl; and Rcand Rdmay each independently be C6-C12 aryl, optionally, selected from phenyl, naphthyl or biphenyl.

[0083] Suitably, Raand Rbare each butyl or hexyl, and Rcand Rdare each phenyl (compound 42 and 43) or Rcand Rdare each naphthyl (compound 45).

[0084] A3- may be selected from Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-. Preferably A3- is Cl- or Br-.

[0085] In one embodiment, X3 is N, each of Ra, Rband Rcis ethyl, Rdis phenyl, and A3- is Br-. (Compound 31)

[0086] In another embodiment, X3is N, each of Ra, Rband Rcis butyl, Rdis phenyl, and A3- is Br-. (Compound 32)

[0087] In another embodiment, X3 is N, each of Ra, Rband Rcis butyl, Rdis naphthyl, and A3- is Br-. (Compound 34 / 36)

[0088] In a preferred embodiment, X3is N, each of Ra, Rband Rcis butyl, Rdis biphenyl, and A3- is Br-. (Compound 37)

[0089] In a preferred embodiment, the catalyst has the structure: (Compound 37).

[0090] In another embodiment, X3 is N, Raand Rbare methyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 40).

[0091] In another embodiment, X3is N, Raand Rbare propyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 41).

[0092] In a preferred embodiment, X3 is N, Raand Rbare butyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 42).

[0093] In a preferred embodiment, the catalyst has the structure:, wherein A- is be selected from Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-. Suitably, A- is Br- (compound 42).

[0094] In a preferred embodiment, X3 is N, Raand Rbare hexyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 43)

[0095] In a preferred embodiment, the catalyst has the structure: (Compound 43)and A3- is Br-. (Compound 44).

[0097] In another embodiment, X3 is N, Raand Rbare methyl, Rcand Rdare biphenyl, and A3- is Br-. (Compound 45).

[0098] In another embodiment, X3 is N, Raand Rbare butyl, Rcand Rdare naphthyl, and A3- is Br-. (Compound 46).

[0099] The base may be an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide. Preferably the base is sodium hydroxide.

[0100] The catalyst may be employed in an amount of 10 mol% or less, preferably in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

[0101] The method may further comprise a subsequent addition of acid, suitably, a Bronsted acid. For example, the acid may be selected from HCl, HBr, H2SO4, HNO3, and CH3COOH, suitably, the acid is an aqueous solution.

[0102] The base may be employed in a dry weight ratio of 2:1 or less per gram of polyethylene terephthalate, suitably, the base is employed in a dry weight ratio of 1.5:1 or less per gram of polyethyelene terephthalate, more suitably, the base is employed in a weight ratio of 1:1 or less per gram of polyethylene terephthalate.

[0103] The weight ratio of base to polyethylene terephthalate may be in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1

[0104] Suitably, the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, optionally from 250 to 650 g / L. Optionally, the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 250 g / L, such as in a concentration of 100 to 250 g / L, optionally in a concentration of 150 to 250 g / L. Advantageously, the method of the invention is carried out at high concentration, thereby reducing water waste, and energy input costs, and overall reducing the environmental impact of the reaction.

[0105] The base may be present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

[0106] Optionally, the base is an alkali metal hydroxide, such as sodium hydroxide.

[0107] Optionally, the base and water form an alkaline solution having a concentration of from 40% w / v to 70% w / v, such as from 45% w / v to 65% w / v.

[0108] Suitably, each of the methods for hydrolysing polyethylene terephthalate disclosed herein comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C..

[0109] Suitably, the method for hydrolysing polyethylene terephthalate is conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0110] Suitably, the method for hydrolysing polyethylene terephthalate involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes.

[0111] In one aspect the present invention provides a method for alkaline hydrolysis of poly(ethylene terephthalate) comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyze at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst having the formula Ic: Formula (Ic):, wherein X2 is N or P, and each n2 is an integer independently selected from 4 to 10, and wherein A2- is an anion.

[0112] Suitably, X2is N.

[0113] Each n2 may independently be 4, 5, 6 or 7.

[0114] Optionally, A2- is selected from the group comprising: Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-.

[0115] Suitably, the catalyst is selected from:wherein A- is Br- or I- or Cl-.

[0116] Suitably, the catalyst is selected from:wherein A- is Br- or I- or Cl-.

[0117] In another aspect, the present invention provides a compound having the formula:wherein each p is an integer independently selected from 0 to 5, wherein each Rx is independently selected from C1-C12 aliphatic, optionally substituted with one or more selected from the group consisting of C1-C6 alkyoxy, C1-C6 thioalkyl, Br, Cl, I, and F.

[0118] Suitably, the catalyst has the formula:.

[0119] Suitably, A- is Br-, Cl- or I-.

[0120] Suitably, each of the methods for hydrolysing polyethylene terephthalate disclosed herein comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C..

[0121] Suitably, the method for hydrolysing polyethylene terephthalate is conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0122] Suitably, the method for hydrolysing polyethylene terephthalate involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes.

[0123] In another aspect the present invention provides a method for hydrolysing poly(bisphenol A carbonate) comprising: combining poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic,wherein each of R3and R4is independently selected from C5-C15 aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

[0124] Suitably, together R1, R2, R3and R4comprise 14 to 36 carbon atoms, such as from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, for example from 16 to 22 carbon atoms.

[0125] Optionally, each of R1and R2is independently C1-C3alkyl, further optionally, each of R1and R2are C1alkyl, preferably methyl.

[0126] Optionally, each of R3and R4is independently selected from C6-C12alkyl.

[0127] Optionally, R3and R4are the same.

[0128] Suitably, R3and R4are C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10 alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl nonyl or decyl.

[0129] Suitably, R1and R2are methyl.

[0130] Suitably, R1and R2are methyl and R3and R4are heptyl, octyl or nonyl. For example, R1and R2are methyl and R3and R4are heptyl, or R1and R2are methyl and R3and R4are octyl, or R1and R2are methyl and R3and R4are nonyl.

[0131] Optionally, A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-.

[0132] Optionally, the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

[0133] Suitably, the base and water form an alkaline solution having a concentration of from 40% w / v to 70% wt / v, such as from 45% w / v to 65% w / v.

[0134] Suitably, the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly (bisphenol A carbonate). Optionally, the catalyst is employed in an amount of from 0.1 mol% to 1.5 mol%, such as from 0.5 mol% to 1 mol%.

[0135] The method may further comprise a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0136] The method may further comprise isolation of bisphenol A, for example, by filtration.

[0137] The dry weight ratio of base to poly(bisphenol A carbonate) is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1

[0138] Optionally, the step of combining poly (bisphenol A carbonate), water, base, and a catalyst, comprises combining poly (bisphenol A carbonate) with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, optionally in a concentration of from 250 to 650 g / L.

[0139] Optionally, the base is present in an amount of 13 molar equivalents or less, such as 10 molar equivalents or less relative to the number of moles of monomer unit of poly (bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly (bisphenol A carbonate).

[0140] Suitably, the catalyst is selected from:, wherein A- is Br- or Cl-.

[0141] Suitably, the methods for hydrolysing poly(bisphenol A carbonate) disclosed herein comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C..

[0142] Suitably, the methods for hydrolysing poly(bisphenol A carbonate) disclosed herein are conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0143] Suitably, the methods for hydrolysing poly(bisphenol A carbonate) involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes.

[0144] In a still further aspect the present invention provides a method for hydrolysing poly(ethylene terephthalate) and poly (bisphenol A carbonate) comprising: combining poly(ethylene terephthalate), poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the polyethylene terephthalate and to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic, wherein each of R3and R4is independently selected from C5-C15 aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

[0145] Optionally, together R1, R2, R3and R4comprise 14 to 36 carbon atoms, suitably, from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

[0146] The polyethylene terephthalate and poly(bisphenol A carbonate) may be mixed or blended together. For example, the polyethylene terephthalate (PET) and poly(bisphenol A carbonate) (PBA-PC) may be a mixed stream of plastic, or for example, the PET and PBA-PCmay be blended together. Optionally, the PET and PBA-PC may be in the form of a molded or extruded article.

[0147] Each of R1and R2may be C1-C3alkyl. For example, each of R1and R2may be C1 alkyl. Preferably each of R1and R2is methyl.

[0148] Each of R3and R4may be independently selected from C6-C12 alkyl.

[0149] Optionally, R3and R4are the same.

[0150] For example, R3and R4may be C6alkyl, C7alkyl, C8alkyl, C9alkyl or C10alkyl. For example, each of R3and R4may be the same and selected from C6alkyl, C7alkyl, C8alkyl, C9 alkyl or C10 alkyl. Suitably, each of R3and R4is selected from hexyl, heptyl, octyl nonyl or decyl. Preferably, each of R3and R4is heptyl, octyl, nonyl or decyl.

[0151] Optionally, R1and R2are methyl.

[0152] Optionally, R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.

[0153] Suitably, A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-.

[0154] Optionally, the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

[0155] For example, the base and water may form an alkaline solution having a concentration in the range of from 40% w / v to 70% w / v, such as from 45% w / v to 65% w / v.

[0156] Optionally, the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

[0157] Optionally, the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly(bisphenol A carbonate).

[0158] The method may further comprise a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0159] The addition of acid may involve adjusting pH to selectively protonate salts of bisphenol A, thereby producing bisphenol A, optionally, wherein adjusting pH to selectively protonate salts of bisphenol A involves adjusting pH to pH 7 to pH 8.5, optionally, from a pH of from pH 7.5 to 8.

[0160] The method may involve isolation of bisphenol A, prior to isolation of terephthalic acid. Optionally, bisphenol A is isolated by filtration.

[0161] Suitably, addition of acid involves lowering pH below pH 3 to protonate salts of terephthalic acid, thereby forming terephthalic acid.

[0162] Optionally, the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0163] Suitably, the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L. Optionally in a concentration of from 250 to 650 g / L.

[0164] Optionally, the base is present in an amount of 13 molar equivalents or less, such as 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

[0165] Optionally, the base is present in an amount of 13 molar equivalents or less, such as 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

[0166] Preferably, the catalyst is selected from:wherein A- is Br- or Cl-.

[0167] Suitably, the method for hydrolysing polyethylene terephthalate and poly(bisphenol A carbonate) disclosed herein comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C..

[0168] Suitably, the methods for hydrolysing polyethylene terephthalate and poly(bisphenol A carbonate) disclosed herein are conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0169] Suitably, the methods for hydrolysing polyethylene terephthalate and poly(bisphenol A carbonate) disclosed herein involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes.

[0170] In a still further aspect the present invention provides a method for hydrolysing poly(ethylene terephthalate) and / or poly (bisphenol A carbonate) comprising: combining poly(ethylene terephthalate) and / or poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the polyethylene terephthalate and / or to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from:wherein X1is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3 aliphatic, wherein each of R3and R4is independently selected from C5-C15 aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

[0171] Optionally, together R1, R2, R3and R4comprise from 14 to 36 carbon atoms, suitably, from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

[0172] When both polyethylene terephthalate and poly(bisphenol A carbonate) are present, the polyethylene terephthalate and poly(bisphenol A carbonate) may be mixed or blended together. For example, the polyethylene terephthalate (PET) and poly(bisphenol A carbonate) (PBA-PC) may be a mixed stream of plastic, or for example, the PET and PBA-PC may be blended together. Optionally, the PET and PBA-PC may be in the form of a moulded or extruded article. The PET and PBA-PC may be attached or connected together.

[0173] Each of R1and R2may be C1-C3alkyl. For example, each of R1and R2may be C1 alkyl. Preferably each of R1and R2is methyl.

[0174] Each of R3and R4may be independently selected from C6-C12 alkyl.

[0175] Optionally, R3and R4are the same.

[0176] For example, R3and R4may be C6alkyl, C7alkyl, C8alkyl, C9alkyl or C10alkyl. For example, each of R3and R4may be the same and selected from C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10 alkyl. Suitably, each of R3and R4is selected from hexyl, heptyl, octyl nonyl or decyl. Preferably, each of R3and R4is heptyl, octyl, nonyl or decyl.

[0177] Optionally, R1and R2are methyl.

[0178] Optionally, R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.

[0179] Suitably, A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-.

[0180] Optionally, the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

[0181] For example, the base and water may form an alkaline solution having a concentration in the range of from 40% w / v to 70% w / v, such as from 45% w / v to 65% w / v.

[0182] Optionally, the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

[0183] Optionally, the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly(bisphenol A carbonate).

[0184] The method may further comprise a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0185] When the method comprises hydrolysis of poly(bisphenol A carbonate), the addition of acid may involve adjusting pH to selectively protonate salts of bisphenol A, thereby producing bisphenol A, optionally, wherein adjusting pH to selectively protonate salts of bisphenol A involves adjusting pH to pH 7 to pH 8.5, optionally, from a pH of from pH 7.5 to 8.

[0186] When the method involves the hydrolysis of poly(bisphenol A carbonate) and polyethylene terephthalate, the method may involve isolation of bisphenol A, prior to isolation of terephthalic acid. Optionally, bisphenol A is isolated by filtration.

[0187] Suitably, addition of acid involves lowering pH below pH 3 to protonate salts of terephthalic acid, thereby forming terephthalic acid.

[0188] Optionally, when the method involves hydrolysis of polyethylene terephthalate, the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0189] Suitably, when the method involves hydrolysis of polyethylene terephthalate, the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in aconcentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, suitably in a concentration of from 250 to 650 g / L.

[0190] Optionally, when the method involves hydrolysis of polyethylene terephthalate, the base is present in an amount of 13 molar equivalents or less, optionally, 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

[0191] Optionally, when the method involves hydrolysis of poly(bisphenol A carbonate), the base is present in an amount of 13 molar equivalents or less, optionally, 10 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

[0192] Preferably, the catalyst is selected from:wherein A- is Br- or Cl-.

[0193] Suitably, the method for hydrolysing polyethylene terephthalate and / or poly(bisphenol A carbonate) disclosed herein comprises heating at a temperature in the range of from 80 to 150°C, optionally, in the range of from 90 to 150°C, for example from 100 to 150°C, such as from 110 to 150°C..

[0194] Suitably, the methods for hydrolysing polyethylene terephthalate and / or poly(bisphenol A carbonate) disclosed herein are conducted at a pressure in the range of from 1 to 10 bar, preferably 1 to 5 bar, suitably, 1 to 2.5 bar, optionally 1 to 1.5 bar, for example at about 1 bar.

[0195] Suitably, the methods for hydrolysing polyethylene terephthalate and / or poly(bisphenol A carbonate) disclosed herein involves heating for a duration of from 1 minute to 48 hours, for example of from 1 minute to 24 hours, such as from 1 minute to 6 hours, or from 1 minute to 3 hours, optionally, from 1 minute to 1 hour, further optionally of from 1 minute to 30 minutes, such as from 1 minute to 15 minutes. DETAILED DESCRIPTION Phase Transfer Catalysts

[0196] Herein disclosed are phase transfer catalysts classified as follows:

[0197] Symmetrical Catalyst: ammonium or phosphonium salts, wherein each substituent is the same, and each substituent is an aliphatic chain, such as an alkyl chain e.g. tetrabutyl ammonium bromide, tetraoctylphosphonium bromide etc.

[0198] 3-Chain Catalyst: ammonium or phosphonium salts bearing a single C1-C4 substituent, such as a single methyl substituent, and three aliphatic chain substituents (e.g. alkyl chain substituents) each comprising more than 4 carbon atoms, e.g. trioctylmethylammonium bromide, trioctylmethylphosphonium bromide etc.

[0199] 2-Chain Catalyst: ammonium or phosphonium salts bearing two C1-C4 substituents, such as two methyl substituents, and two aliphatic chain substituents (e.g. alkyl chain substituents) each comprising more than 4 carbon atoms, e.g. dioctyldimethylammonium bromide, dioctyldimethylphosphonium bromide etc.

[0200] 1-Chain Catalyst: ammonium or phosphonium salts bearing three C1-C4substituents, such as three methyl substituents, and one aliphatic chain substituent (e.g. alkyl chain substituent) comprising more than 4 carbon atoms e.g. trimethyloctylammonium bromide, trimethylhexadecylammonium bromide, tributyldodecylphosphonium bromide etc.

[0201] Benzylated Catalyst: ammonium or phosphonium salts bearing one or two -CH2- Aryl groups

[0202] Aromatic Catalyst: ammonium or phosphonium salts bearing one or more aromatic substituents e.g. methyl pyridinium iodide, or trimethylphenylammonium bromide.

[0203] Ionophore Catalyst: compounds that form complexes with ions and facilitate transport of ions e.g. crown ethers. 2-chain and 1-chain catalysts may have the formulawherein X1is N or P, wherein A1- is an anion, wherein each of R1, R2, R3and R4is independently selected from C1-C20aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms, and wherein at least two of R1, R2, R3and R4are independently selected from C2-C20 aliphatic.

[0205] A1- may be selected from Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-. Suitably, A1- is Br- or Cl-.

[0206] X1is N or P. Suitably, X1is N.

[0207] Preferably, X1 is N and A1- is Br- or Cl-.

[0208] Each of R1, R2, R3and R4may be independently selected from C1-C20 alkyl, and at least two of R1, R2, R3and R4are independently selected from C2-C20alkyl.

[0209] For example, each of R1, R2, R3and R4may independently be selected from C4- C8alkyl.

[0210] In some catalysts (i.e. symmetrical catalysts), R1, R2, R3and R4may be the same, i.e. R1=R2=R3=R4.

[0211] In some catalysts, R1, R2, R3and R4are C4, C5or C6alkyl, optionally, wherein R1, R2, R3and R4are selected from butyl, pentyl or hexyl.

[0212] In a preferred symmetrical catalyst, each of R1, R2, R3and R4is pentyl. For example, each of R1, R2, R3and R4may be C5alkyl, optionally, pentyl, and X1is N.

[0213] Suitably, each of R1, R2, R3and R4may be C5alkyl, optionally, pentyl; X1is N; and A1- is Br- or Cl-.

[0214] A preferred symmetrical catalyst is tetrapentylammonium bromide.

[0215] Also disclosed herein are 3-chain catalysts.

[0216] Suitably, in a 3-chain catalyst, R1is C1-C4alkyl, preferably methyl.

[0217] R1may be C1alkyl, optionally, methyl and each of R2, R3and R4may be independently selected from C5 to C11 aliphatic, optionally, C5 to C11 alkyl.

[0218] Suitably, R1is C1 alkyl, optionally, methyl and R2, R3and R4are the same.

[0219] R1may be C1 alkyl, optionally, methyl and each of R2, R3and R4may be independently C5-C9aliphatic, optionally, C5-C9alkyl.

[0220] Suitably, R1is C1alkyl, optionally, methyl and each of R2, R3and R4is C5-C9aliphatic, optionally, C5-C9 alkyl. For example, R1may be C1 alkyl, optionally, methyl and each of R2, R3and R4may be pentyl, hexyl, heptyl, octyl or nonyl.

[0221] In a preferred 3-chain catalyst, R1is methyl, and each of R2, R3and R4is hexyl.

[0222] Suitably, R1is methyl, and each of R2, R3and R4is hexyl, and X1is N. More suitably, R1is methyl, and each of R2, R3and R4is hexyl, X1is N, and A- is Br- or Cl-.

[0223] A preferred 3-chain catalyst is methyltrihexylammonium bromide.

[0224] Also disclosed herein are 2-chain catalysts.2-chain catalysts are the preferred catalyst for PET depolymerization disclosed herein. 2-chain catalysts are the preferred catalyst for BPA-PC depolymerization disclosed herein. 2-chain catalysts are the preferred catalysts for depolymerization of mixed stream plastics, for example a mixture of PET and BPA-PC.

[0225] Suitably, in a 2-chain catalyst, R1and R2are C1-C4 alkyl, optionally, methyl, and R3and R4are each independently C6-C18aliphatic, optionally, C6-C18alkyl.

[0226] For example, R1and R2may be C1alkyl, optionally, methyl, and R3and R4may each independently C6-C18aliphatic, optionally, C6-C18alkyl. Suitably, R3and R4are each independently C6-C10 aliphatic, optionally, C6-C10 alkyl. Optionally, R3and R4are the same.

[0227] Suitably, R1and R2are methyl, and R3and R4are C6-C8 alkyl, optionally, C7 alkyl. For example, R3and R4may be selected from hexyl, heptyl and octyl, optionally, R3and R4are heptyl.

[0228] Suitably, X1 is P, and each of R1, R2, R3and R4is butyl, and A1- is Br-. (Compound 3).

[0229] Suitably, X1 is N, and each of R1, R2, R3and R4is butyl, and A1- is Cl-. (Compound 4).

[0230] Suitably, X1is N, and each of R1, R2, R3and R4is butyl, and A1- is Br-. (Compound 5).

[0231] Suitably, X1 is N, and each of R1, R2, R3and R4is butyl, and A1- is I-. (Compound 6).

[0232] Suitably, X1is N, and each of R1, R2, R3and R4is pentyl, and A1- is Br-. (Compound 7)

[0233] Suitably, X1 is N, and each of R1, R2, R3and R4is hexyl, and A1- is Br-. (Compound 8).

[0234] Suitably, X1is P, and each of R1, R2, R3and R4is octyl, and A1- is Br-. (Compound 9).

[0235] Suitably, X1 is N, and each of R1, R2, R3and R4is octyl, and A1- is Br-. (Compound 10).

[0236] Suitably, X1is N, R1is methyl, and each of R2, R3and R4is pentyl, and A1- is Br-. (Compound 11).

[0237] Suitably, X1is N, R1is methyl, and each of R2, R3and R4is hexyl, and A1- is Br-. (Compound 12).

[0238] Suitably, X1 is N, R1is methyl, and each of R2, R3and R4is octyl, and A1- is Br-. (Compound 13).

[0239] Suitably, X1is N, R1is methyl, and each of R2, R3and R4is octyl, and A1- is I-. (Compound 14).

[0240] Suitably, X1 is N, R1is methyl, and each of R2, R3and R4is octyl, nonyl or decyl, and A1- is Cl-. (Compound 15).

[0241] Suitably, X1 is N, each of R1and R2is methyl, each of R3and R4is hexyl, and A1- is I-. (Compound 16).

[0242] Preferably, the catalyst has the structure:CF3C(O)O-.

[0243] Preferably, X1is N, each of R1and R2is methyl, each of R3and R4is heptyl, and A1- is Br-. (Compound 17).

[0244] Preferably, X1 is N, each of R1and R2is methyl, each of R3and R4is octyl, and A1- is Br-.

[0245] In a preferred embodiment, the catalyst has the structure:and CF3C(O)O-.

[0246] For example, the catalyst has the structure:, wherein A- is Br- (Compound 18).

[0247] Suitably, X1is N, each of R1and R2is methyl, each of R3and R4is nonyl, and A1- is Br-. (Compound 19).

[0248] Suitably, X1 is N, each of R1and R2is methyl, each of R3and R4is undecyl, and A1- is Br-. (Compound 20).

[0249] Suitably, X1is N, each of R1and R2is methyl, each of R3and R4is decyl, and A1- is Br-.

[0250] Suitably, X1 is N, each of R1and R2is methyl, each of R3and R4is dodecyl, and A1- is Br-. (Compound 21).

[0251] Suitably, X1is N, each of R1and R2is methyl, each of R3and R4is heptyl, and A1- is I-. (Compound 52)

[0252] Suitably, the catalyst has the structure: (Compound 52).

[0253] Preferably, X1 is N, each of R1and R2is methyl, each of R3and R4is octyl, and A1- is Cl-. (Compound 53)

[0254] Preferably, the catalyst has the structure: (Compound 53)wherein X3 is N, and A3- is an anion, wherein Raand Rbare each independently selected from C1-C8aliphatic, wherein Rcis selected from C1-C8aliphatic or C6-C20aryl, and wherein Rdis C6-C20aryl, or wherein Rcand Rdtogether form a ring structure having one or more C5-C10 aryl substituents, and wherein a catalyst of formula (II) comprises at least 18 carbon atoms.

[0256] Optionally, a catalyst of formula II comprises from 18 to 36 carbon atoms, such as from 18 to 30 carbon atoms, optionally from 18 to 26 carbon atoms.

[0257] A3- may be selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-. Suitably, A3- is Br- or Cl-.

[0258] X3 is N or P. Suitably, X3 is N.

[0259] Preferably, X3is N and A- is Br- or Cl-.

[0260] Raand Rbmay be independently selected from C1to C6aliphatic, optionally, C1to C6 alkyl.

[0261] Optionally, Ra, Rband Rcare the same.

[0262] Raand Rbmay be independently selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl.

[0263] Rdmay be selected from phenyl, biphenyl and naphthyl.

[0264] A preferred catalyst disclosed herein according to Formula (II) are benzylated catalysts. Benzylated catalysts are ammonium or phosphonium catalysts comprising one or two -CH2-Aryl groups.

[0265] Suitably, each of Ra, Rb, and Rcis C4 alkyl, optionally butyl, and Rdis biphenyl.

[0266] Suitably, Raand Rbare C1-C6 alkyl, optionally, selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl, and Rc and Rd are phenyl, biphenyl or naphthyl.

[0267] In a preferred benzylated catalyst, Raand Rbare each selected from propyl, butyl, pentyl or hexyl, and Rcand Rdare each selected from phenyl, naphthyl or biphenyl.

[0268] Suitably, X3 is N. Suitably, A3- is Br- or Cl-.

[0269] Suitably, X3 is N, each of Ra, Rband Rcis ethyl, Rdis phenyl, and A3- is Br-. (Compound 31)

[0270] Suitably, X3is N, each of Ra, Rband Rcis butyl, Rdis phenyl, and A3- is Br-. (Compound 32)

[0271] Suitably, X3 is P, each of Ra, Rband Rcis butyl, Rdis phenyl, and A3- is Br-. (Compound 33)

[0272] Suitably, X3is N, each of Ra, Rband Rcis butyl, Rdis naphthyl, and A3- is Br-. (Compound 34 / 36)

[0273] Suitably, X3 is P, each of Ra, Rband Rcis butyl, Rdis naphthyl, and A3- is Br-. (Compound 35)

[0274] Preferably, X3is N, each of Ra, Rband Rcis butyl, Rdis biphenyl, and A3- is Br-. (Compound 37)

[0275] Preferably, the catalyst has the structure: (Compound 37).

[0276] Suitably, X3 is N, Raand Rbare methyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 40)

[0277] Suitably, X3is N, Raand Rbare propyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 41)

[0278] Preferably, X3 is N, Raand Rbare butyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 42)

[0279] Preferably, the catalyst has the structure: (Compound 42), wherein A- is be selected from Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-.

[0280] Preferably, X3 is N, Raand Rbare hexyl, Rcand Rdare phenyl, and A3- is Br-. (Compound 43)

[0281] Preferably, the catalyst has the structure: (Compound 43), wherein A- is be selected from Cl-, Br-, I-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-.

[0282] Suitably, X3 is N, Raand Rbare methyl, Rcand Rdare naphthyl, and A3- is Br-. (Compound 44)

[0283] Suitably, X3is N, Raand Rbare methyl, Rcand Rdare biphenyl, and A3- is Br-. (Compound 45)

[0284] Suitably, X3 is N, Raand Rbare butyl, Rcand Rdare naphthyl, and A3- is Br-. (Compound 46)

[0285] Preferred benzylated catalysts include Biphenyltributylammonium bromide (compound 37), dibenzyldibutylammonium bromide (compound 42), and dibenzyldihexylammonium bromide (compound 43).

[0286] The catalysts disclosed herein have utility in depolymerizing polymers comprising PET units, such as PET. Optionally, the PET may have a density in the range of from 1.30 to 1.45 g / cm3, such as from 1.38 g / cm3to 1.41 g / cm3.

[0287] For example, the phase transfer catalysts disclosed herein may be used in a method for hydrolysing a polymer comprising polyethylene terephthalate units, such as polyethylene terephthalate, such method comprising the steps of: (i) combining the polymer comprising polyethyelene terephthalate units, (such as polyethylene terephthalate), water, base and the phase transfer catalyst, and heating for a time sufficient to hydrolyse at least in part the polymer comprising polyethylene terephthalate units, thereby producing terephthalate salt; and (ii) adding acid to protonate the terephthalate salt, thereby forming terephthalic acid.

[0288] The base is suitably, an alkali metal hydroxide or an alkaline earth metal hydroxide, more suitably, the base is selected from sodium hydroxide, potassium hydroxide, and magnesium hydroxide.

[0289] The catalyst is employed in an amount of 10 mol% or less, preferably in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

[0290] The acid is suitably selected from HCl, HBr, H2SO4, HNO3, CH3COOH, suitably, the acid is an aqueous solution.

[0291] The base may be employed in a weight ratio of 2:1 or less per gram of polyethylene terephthalate, suitably, wherein the base is employed in a weight ratio of 1.5:1 or less per gram of polyethyelene terephthalate, more preferably wherein the base is employed in a weight ratio of 1:1 or less per gram of polyethylene terephthalate.

[0292] The weight ratio of base to polyethylene terephthalate is suitably in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0293] The base may be present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

[0294] Also disclosed herein is a method for the alkaline hydrolysis of poly(ethylene terephthalate) comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyze at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst selected from the following group: Formula (Ia):wherein X is N or P, and each n is an integer independently selected from 2 to 5, and wherein A- is an anion; Formula (Ib):, wherein X1 is N or P, and each n1 is an integer independently selected from 2 to 7, and wherein A1- is an anion; and Formula (Ic):, wherein X2 is N or P, and each n2 is an integer independently selected from 4 to 15, and wherein A2- is an anion; and optionally, further comprising the addition of an acid, thereby forming terephthalic acid.

[0295] Further, the phase transfer catalysts disclosed herein may be used in a method for hydrolysing a polymer comprising poly(bisphenol A carbonate), such method comprising the steps of: (i) combining the polymer comprising poly(bisphenol A carbonate), water, base and the phase transfer catalyst, and heating for a time sufficient to hydrolyse at least in part the polymer comprising poly(bisphenol A carbonate) thereby producing salts of bisphenol A; and (ii) adding acid to protonate the salts of bisphenol A, thereby forming bisphenol A.

[0296] The base is suitably, an alkali metal hydroxide or an alkaline earth metal hydroxide, more suitably, the base is selected from sodium hydroxide, potassium hydroxide, and magnesium hydroxide.

[0297] The catalyst is employed in an amount of 10 mol% or less, preferably in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly(bisphenol A carbonate). Optionally, the catalyst is employed in an amount of from 0.1 to 1 mol% per mole of monomeric repeating unit of poly(bisphenol A carbonate).

[0298] The acid is suitably selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0299] The base may be employed in a weight ratio of 2:1 or less per gram of poly(bisphenol A carbonate), suitably, wherein the base is employed in a weight ratio of 1.5:1 or less per gram of poly(bisphenol A carbonate), more preferably wherein the base is employed in a weight ratio of 1:1 or less per gram of poly(bisphenol A carbonate).

[0300] The weight ratio of base to poly(bisphenol A carbonate)is suitably in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0301] The base may be present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

[0302] The phase transfer catalysts disclosed herein may be used in a method for hydrolysing polyethylene terephthalate and poly(bisphenol A carbonate), such method comprising the steps of: (i) combining the polyethylene terephthalate, poly(bisphenol A carbonate), water, base and the phase transfer catalyst, and heating for a time sufficient to hydrolyse at least in part polyethylene terephthalate and the poly(bisphenol A carbonate) to thereby produce salts of terephthalic acid and of bisphenol A; and (ii) adding acid to protonate the salts of terephthalic acid and the salts of bisphenol A, thereby forming terephthalic acid and bisphenol A.

[0303] Suitably, the adding acid step involves adjusting the pH to selectively protonate salts of bisphenol A, prior to protonation of salts of terephthalic acid.

[0304] Optionally, the adding acid step involves adjusting the pH to from to pH 7 to pH 8.5, optionally to a pH of from pH 7.5 to pH 8.0, to protonate salts of bisphenol A, thereby producing bisphenol A.

[0305] Further optionally, the method involves isolation of bisphenol A, prior to isolation of terephthalic acid.

[0306] Suitably, the method involves isolation of bisphenol A by filtration.

[0307] Suitably, the method involves protonation of salts of terephthalic acid by lowering pH to below pH 3, optionally, the method involves protonation of salts of terephthalic acid by lowering the pH to a pH in the range of from 1 to 3, suitably, in the range of from 1.5 to 2.5.

[0308] The base is suitably, an alkali metal hydroxide or an alkaline earth metal hydroxide, more suitably, the base is selected from sodium hydroxide, potassium hydroxide, and magnesium hydroxide.

[0309] The catalyst is employed in an amount of 10 mol% or less, preferably in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomericrepeating unit of poly(bisphenol A carbonate). Optionally, the catalyst is employed in an amount of from 0.1 to 1 mol% per mole of monomeric repeating unit of poly(bisphenol A carbonate).

[0310] The acid is suitably selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

[0311] The base may be employed in a weight ratio of 2:1 or less per gram of poly(bisphenol A carbonate), suitably, wherein the base is employed in a weight ratio of 1.5:1 or less per gram of poly(bisphenol A carbonate), more preferably wherein the base is employed in a weight ratio of 1:1 or less per gram of poly(bisphenol A carbonate).

[0312] The weight ratio of base to poly(bisphenol A carbonate)is suitably in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.

[0313] The base may be present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

[0314] The invention will be more readily appreciated by a review of the examples which follow. EXAMPLES

[0315] The following examples were conducted to ascertain the contribution made by structural features of quaternary phosphonium and ammonium based PTCs in catalysing the alkaline hydrolysis of polymers comprising PET units, such as in the alkaline hydrolysis of PET.

[0316] To date, much of the investigations on PET depolymerization has employed smaller PET flakes, which have a larger surface area per gram of PET, and therefore represent more reactive, and less challenging substrates. In order to develop a platform for industrial application, we employed PET flakes of larger size, circa 5 mm square flakes, which is consistent with the output from mechanical PET recycling. Materials and Methods

[0317] The PET was derived from colourless water bottles purchased from a large supermarket chain. The average molecular weight for bottle grade PET ranges from 24000 to 36000 g mol-1. The density of the PET was in the range of from 1.38 to 1.41 g / cm3.

[0318] Once emptied of their contents and labels were removed, the PET bottles were cut into flakes of approx.5 mm square in size.

[0319] Sodium hydroxide pellets were purchased from Sigma Aldrich, and used without further purification.

[0320] Hydrochloric acid was purchased from Sigma Aldrich (conc.) and dilute solutions were prepared therefrom using standard procedures.

[0321] Phase transfer catalysts were purchased where available or synthesized in accordance with literature procedures, unless otherwise specified. PET hydrolysis procedure

[0322] An oven dried carousel flask was charged with water (5 mL), sodium hydroxide (0.500 g) and catalyst (5 mol %).aThe flask was placed under an atmosphere of nitrogen (balloon), and the reaction was stirred for 20 min at 90 °C. Polyethylene terephthalate flakes (ca. 5 mm squares, 0.500 g) were added and the mixture was stirred (500 RPM) for 3 h. The flask was removed from the carousel and cooled in an ice-bath for 10 min. The reaction mixture was then filtered, and the residue was washed with water (5 mL x 2). The filtrate was adjusted, with cooling, to pH 2-3 using dilute HCl and the resulting precipitate was filtered. The solids were washed withwater (5 mL) and the product was dried for 4 h in a vacuum oven at 60̊ C. The yield of terephthalicacid was determined by1H NMR spectroscopy using 4-iodoanisole as an internal standard: known masses of product (> 15 mg) and 4-iodoanisole (> 15 mg) were weighed into a sample vial and dissolved in DMSO-d6. The integrals corresponding to both TPA and isophthalic acid (a common additive utilised in PET production) were used to determine yield.aMol% of catalyst is related to the number of moles of monomeric units (2.6 mmol) present in 0.500 g of polymer.

[0323] Proton Nuclear Magnetic Resonance (NMR) spectra were recorded on Bruker DPX 400 MHz and Bruker Avance II 600MHz spectrometers, using CDCl3 and DMSO-d6 as solvents, and referenced relative to residual CHCl3 (δ = 7.26 ppm) or DMSO (δ = 2.50 ppm). Carbon NMR spectra were recorded on the same instruments (101 MHz and 151 MHz respectively) with total proton decoupling. Phosphorus NMR spectra were recorded on the Bruker DPX400 machine (162 MHz). Infrared spectra were obtained on a Perkin Elmer Spectrum 100 FT-IR spectrometer equipped with a universal ATR sampling accessory. ESI mass spectra were acquired using a Waters Micromass LCT- time of flight mass spectrometer (TOF), interfaced to a Waters 2690 HPLC. The instrument was operated in either positive or negative mode as required. APCI experiments were carried out on a Bruker microTOF-Q III spectrometer interfaced to a Dionex UltiMate 3000 LC or direct insertion probe. Agilent tuning mix APCI-TOF was used tocalibrate the system. Hydrolysis experiments were carried out with Radleys Carousel 12 Plus Reaction Station. HPLC grade water was purchased from Sigma-Aldrich and used as the reaction medium for the basic hydrolysis of PET. Colourless polyethylene terephthalate bottles were purchased from a local large supermarket chain and cut into flakes (ca.5 mm square). Unless otherwise noted, all commercially available compounds were used as provided, without any further purification.

[0324] Test System

[0325] The test system employed to assess the efficacy of various catalysts was as follows: ^ 500 mg PET flakes (approx.5 mm square), ^ Base: NaOH weight ratio of 0.5:2 to 2:1 relative to PET, preferably, a weight ratio of 1:1. ^ Catalyst: 1 mol% to 10 mol% relative to the number of moles of monomeric units present in PET polymer, e.g. the number of monomeric units present in 0.5 g of PET is 2.6 mmol, which enables the calculation of the required amount of catalyst based on the mass of PET used. ^ Water: 5 mL or 2.5 mL ^ Stirring: 500 rpm ^ Temperature: 90°C

[0326] Scheme 1 below illustrates the test system, along with different catalyst classes investigated.

[0327] Scheme 1: reaction test conditions for alkaline catalysed depolymerization of PET. Catalysts were classified as follows: Symmetrical Catalyst: ammonium or phosphonium salts, wherein each substituent is the same, and each substituent is an aliphatic chain, such as an alkyl chain e.g. tetrabutyl ammonium bromide, tetraoctylphosphonium bromide etc. 3 Chain Catalyst: ammonium or phosphonium salts bearing a single C1-C4substituent, such as a single methyl substituent, and three aliphatic chain substituents (e.g. alkyl chain substituents) each comprising more than 4 carbon atoms, e.g. trioctylmethylammonium bromide, trioctylmethylphosphonium bromide etc. 2 Chain Catalyst: ammonium or phosphonium salts bearing two C1-C4substituents, such as two methyl substituents, and two aliphatic chain substituents (e.g. alkyl chain substituents) each comprising more than 4 carbon atoms, e.g. dioctyldimethylammonium bromide, dioctyldimethylphosphonium bromide etc. 1 Chain Catalyst: ammonium or phosphonium salts bearing three C1-C4substituents, such as three methyl substituents, and one aliphatic chain substituent (e.g. alkyl chain substituent)comprising more than 4 carbon atoms e.g. trimethyloctylammonium bromide, trimethylhexadecylammonium bromide, tributyldodecylphosphonium bromide etc. Benzylated Catalyst: ammonium or phosphonium salts bearing one or two -CH2-Aryl groups. Aromatic Catalyst: ammonium or phosphonium salts bearing one or more aromatic substituents e.g. methyl pyridinium iodide, or trimethylphenylammonium bromide. Ionophore Catalyst: compounds that form complexes with ions and facilitate transport of ions e.g. crown ethers.

[0328] In Table 1 below, the alkaline hydrolysis of PET catalysed by symmetrical PTCs was investigated: Table 1: Alkaline hydrolysis of PET catalysed by symmetrical PTCsEntry PTC Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions. 1 None 0 - 4.2 2cNone 0 - 3.9 3 1 4 Soluble 3.2 4 2 4 Soluble 3.7 5 3 16 Soluble 49.4 6 4 16 Soluble 32.2 7 5 16 Soluble 31.8 8 6 16 Soluble 30.4 9 7 20 finely dispersed 67.8 10 8 24 Insolubled47.1 11 9 32 Insoluble 37.6 12 10 32 Insoluble 38.8 aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard. cRepeat of the experiment outlined in entry 1. d’Insoluble’ as used herein implies the bulk of the catalyst forms discrete aggregated phase(s) under the reaction conditions, it does not imply that no fraction of the catalyst is soluble

[0329] In the absence of any PTC, very low product yields of 4% were reproducibly obtained (entries 1-2). Tetramethylphosphonium- and ammonium salts 1-2 (entries 3-4) appear to moderately inhibit hydrolysis, however the commonplace water-soluble tetrabutylphosphonium- and ammonium salts 3-6 exhibited appreciable activity (entries 5- 8). The more lipophilic phosphonium salt 3 considerably outperformed its ammonium variants 4-6, while variation of the anionic component had – as expected – little influence on the outcome once the catalyst is soluble in the reaction medium. The tetrapentyl homologue 7 exhibited interesting behaviour: it is partially soluble in the reaction medium; and the portion not dissolved is very finely dispersed. This catalyst promoted the reaction with considerably superior efficacy to the tetrabutyl analogue 5 (entry 9). Further chainextension led to increasing levels of insolubility and diminished yields (i.e.9-10, entries 10- 12).

[0330] In Table 2 the alkaline hydrolysis of PET catalysed by 3-chain PTCs was investigated. Table 2: Alkaline hydrolysis of PET catalysed by 3-chain PTCsaEntry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bcondns. 1 11 16 soluble 56.4 2 12 19 finely dispersed 59.0 3 13 25 insolublec55.5 4 14 25 insoluble 43.7 5 15 25-31 insoluble 27.6aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours. bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard. c’Insoluble’ as used herein implies the bulk of the catalyst forms discrete aggregated phase(s) under the reaction conditions, it does not imply that no fraction of the catalyst is soluble

[0331] The evaluation of catalysts characterised by 3 longer chains is outlined in Table 2. The tripentylmethylammonium species 11 facilitated the formation of 2 in appreciable yield (entry 1). The partially soluble, finely dispersed homologue 12 is capable of marginally greater activity (entry 2) – however as observed earlier (vide supra), lipophilicity could not thereafter be increased with advantage (i.e.13-15, entries 3-5).

[0332] In Table 3 the alkaline hydrolysis of PET catalysed by 2-chain catalysts was assessed. The two-chain catalyst class were the most useful and instructive (Table 3). The soluble catalyst 16 possesses only 14 carbon atoms yet could facilitate hydrolysis with >40% yield (entry 1) – considerably greater than that associated with the use of the 16- carbon symmetrical material 5 (compare to Table 1, entry 7). Augmentation of each longer chain by one methylene unit (i.e.17, entry 2) resulted in a soluble catalyst with 16-carbon atoms and strikingly improved efficacy superior to that associated with any catalyst hitherto evaluated. Table 3: Alkaline hydrolysis of PET catalysed by 2-chain PTCsaEntry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions 1 16 14 soluble 41.1 2 17 16 soluble 81.9 3 18 18 finely dispersed 56.6 4 19 20 insoluble 57.6 5 20 24 insoluble 49.8 6 21 26 insoluble 42.0 7 22 34 insoluble 33.3 8 23 38 insoluble 31.3aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours. bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard.

[0333] Most interestingly, further elongation of the 2 chains by a methylene unit (i.e. catalyst 18, entry 3) resulted a finely dispersed system and a reduction in performance under these conditions. As before, once a design change led to catalyst insolubility without fine dispersion under the reaction conditions, efficacy declined and all further chain elongations resulted in decreasingly active catalysts (i.e.19-23, entries 4-8) under these conditions.

[0334] Single chain catalysts, such as quaternary ammonium salts comprising a long alkyl chain (Table 4) proved relatively ineffectual as catalysts, whether soluble or not (i.e. 24-27, entries 1-4). Furthermore, these catalysts gave rise to emulsions which complicate the isolation of TPA. The phosphonium salts 28 and 29 are included here and mediate hydrolysis with moderate efficacy (superior to that associated with 24-27, entries 4-6). These catalysts possess one chain longer than the others, yet their ‘small’ substituents are of 4-6 carbon atoms in length. Hence, they can be seen as a hybrid of single-chain (Table 4) and mid-sized symmetrical systems (e.g.3, Table 1) – which would correlate well with the levels of activity observed. From this perspective, the longer chain is not contributing to efficacy more than the shorter substituents - and it is noteworthy that adherence of the PET flakes to each other was observed in both experiments.Entry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions 1c24 11 soluble 17.1 2c25 13 soluble 26.9 3c26 17 soluble 32.8 4c27 19 soluble 29.7 5d28 24 insoluble 42.9 6d29 32 insoluble 53.4aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours.bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard.cFormation of an emulsion as the reaction progressed was observed.dSevere adherence of the PET flakes to each other was observed.

[0335] Catalysts incorporating benzyl (or similar) units were next examined (Table 5). It was hypothesised that these catalysts would hold potential due to the possibility of attractive π-stacking interactions with the polymer. Table 5: Alkaline hydrolysis of PET catalysed by benzylated PTCsaEntry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions. 1 30 10 soluble 5.6 2 31 13 soluble 8.8 3 32 19 soluble 43.6 4 33c19 soluble 19.7 53423 insolubled58.46 35c23 insoluble 14.6 7 36 23 finely dispersed 53.2 8 37 25 finely dispersed 67.2 9 38 27 insoluble 19.2 10 39 25 insoluble 40.5 11 40 16 soluble 18.9 12 41 20 insoluble 33.4 13 42 22 insoluble 71.2 14 43 26 insoluble 65.9 15 44 24 insoluble 53.3 16 45 28 insoluble 39.2 17 46 30 insoluble 60.5 aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours. bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard. cCatalyst decomposition. d’Insoluble’ as used herein implies the bulk of the catalyst forms discrete aggregated phase(s) under the reaction conditions, it does not imply that no fraction of the catalyst is soluble

[0336] The small and soluble trimethylbenzyl ammonium salt 30 and its triethyl homologue 31 (entries 1-2) exhibited little activity under these conditions. The considerably more lipophilic ammonium salt 32 was shown to be a more suitable catalyst (entry 3), while it’s phosphonium variant 33 decomposed (entry 4).

[0337] Extension of the pi-system was generally advantageous (i.e. catalysts 34- 38 entries 5-6) unless either a phosphonium salt (entry 7) or an anthracene unit (entry 9) was involved. The dioctylisoquinolinium salt 39 (entry 10) was a moderately effective catalyst which lacked the activity of simpler systems mentioned above – so investigations along these lines were halted and attention switched to novel dibenzylated systems.

[0338] As expected, the small, soluble salt 40 did not excel as catalyst (entry 11), however its dipropyl- and dibutyl- analogues (41 and 42, entries 12 and 13 respectively) represented significant improvements – with the latter catalyst promoting the reaction with >70% yield. Most interestingly, the immediate penalty paid from an efficiency standpoint when catalysts in previous classes became wholly insoluble in the reaction medium is not of the same magnitude in this class of promoter – as can be seen from the impressive performance of the insoluble 42 and the even more lipophilic variant 43 (entry 14); which aggregate during the reaction and do not visibly interact with the PET. Bis-naphthyl / bis- biphenyl analogues of 40 and 42 (i.e. catalysts 44, 45 and 46, entries 15-17) proved to be serviceable catalysts yet all were less effective than catalyst 42.

[0339] The efficacy of aromatic and ionophore catalysts was next investigated (Table 6). Table 6: Aromatic- and ionophore-based catalystsaEntry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions 1 47 9 Soluble 7.0 2 48c6 Soluble 4.1 3 49c13 Insolubled14.0 4 50c24 Insoluble 6.5 5 51 10 Soluble 5.3 aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours. bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard. cCatalyst decomposition. d’Insoluble’ as used herein implies the bulk of the catalyst forms discrete aggregated phase(s) under the reaction conditions, it does not imply that no fraction of the catalyst is soluble

[0340] The simple trimethylanilinium species 47 possessed little activity (entry 1) while both pyridinium salts 48 and 49 and the tetraphenylphosphonium salt 50 decomposed (entries 2- 4). The ionophore 51 (15-crown-5) – an efficient binder of Na cations – was also inactive, which strongly indicates that effective delivery of the hydroxide anion to the PET surface is most important for catalyst competency.

[0341] The effect of increasing lipophilicity on catalyst performance is provided in Scheme 2.Scheme 2: Effect of increasing lipophilicity on the performance

[0342] Without being bound by theory, it is considered that in ammonium and phosphonium PTCs as classified herein (symmetrical, 3-chain catalysts, 2-chain catalysts and 1- chain catalysts), which catalysts comprising aliphatic chains tethered to the nitrogen or phosphorous atom, catalyst performance is maximized when the catalyst is is as lipophilic as possible while being either soluble or finely dispersed (cloudy solution) in the reaction medium (see Scheme 2 above). It is thought that such favourable lipophilicity and solubility avoids a triphasic reaction medium scenario and explains why seemingly very small structural changes to the most lipophilic soluble / finely dispersed systems can lead to dramatic losses of activity (e.g.compare the activity of 16 and 18 to 17, and 5 and 8 to 7). It may also account for the discrepancies in literature data – comparing studies using different loadings, reaction temperatures and NaOH concentrations is likely to be evaluating catalysts under very different conditions vis a vis catalyst solubility.

[0343] Once an aliphatic catalyst is insoluble and aggregating under the reaction conditions, further increases in catalyst lipophilicity are deleterious to activity (e.g. compare 18 to 21 and 8 to 10; also the more lipophilic phosphonium salt 3 is superior to the less lipophilic ammonium salt 5 (both soluble), yet the phosphonium salt 9 is marginally inferior to 10 - as both are insoluble). This would imply that either the majority of the catalysis is carried out by that mole fraction of the catalyst present in aqueous solution, or that bigger, insoluble catalysts are incrementally less able to extract hydroxide from aqueous solution and deliver it to the surface of the also insoluble PET, or both.

[0344] When comparing symmetrical catalysts, 3-chain catalysts, 2-chain catalysts and 1-chain catalysts as defined herein, 2-chain catalysts were clearly superior. The general order of efficacy is as follows: 2-Chain catalysts > 3-chain catalysts >> 1-chain catalysts

[0345] This can be clearly seen by comparing the activity of catalysts 17, 11 and 5 each of which comprises 16 carbon atoms, and also catalyst 26 which contains 17 carbon atoms.

[0346] It is thought that the 2-chain catalysts such as catalysts 17 and 18, represent an advantageous balance between being able to deliver coordinated hydroxide to the ester carbonyl being attacked (facilitated by a small hydrophilic ‘head’ unlikely to cause significant steric hindrance) and the ability to associate with the PET surface through Van der Waals attractive forces between the hydrophobic polymer and the two long aliphatic catalyst chains.

[0347] In contrast to the 2-chain and 3-chain catalysts comprising 16 carbon atoms, debenzylated species 40 which also contains 16 carbon atoms is less active than catalysts 17, 11 or 15. However, as outlined above, for benzylated catalysts, a general improvement in catalyst performance was observed as the pi-system is extended (Table 5). In addition, benzylated phosphonium salts were unsuitable for catalysis under these reaction conditions due to catalyst decomposition.

[0348] It was thought that if the solubility of an active, soluble catalyst is reduced to the point of heterogeneity, that activity would be negatively impacted, while the opposite would be expected if an active, finely dispersed catalyst was rendered soluble. To test this, the insoluble iodide variant of the highly active, soluble catalyst 17 (i.e.52) and the soluble chloride analogue of the less active higher finely dispersed homologue 18 (i.e.53) were synthesised and evaluated(Table 7). The heterogenous iodide 52 proved markedly inferior to 17, (entries 1-2) while the soluble, more lipophilic cation containing (than 17) catalyst 53 accelerated the PET depolymerisation more efficiently than all other catalysts evaluated in this study (entries 3-4). Table 7: Manipulation of catalyst solubility and activity via the halide counterionaEntry Catalyst No. of carbon atoms Solubility under reaction Yield (%)bconditions. 1 17c16 soluble 81.9 2 52 16 insolubled58.4 3 18c18 insoluble 70.6 4 53 18 soluble 88.9 aReaction conditions: catalyst loading of 5 mol% relative to the number of moles of monomeric unit in PET, NaOH (500 mg, 4.8 equivalent relative to catalyst), H2O (5 mL), Temperature: 90 C, Stirring: 500 rpm, Duration: 3 hours. bDetermined by1H NMR spectroscopy using 4-iodoanisole as an internal standard. cData from Table 3 d’Insoluble’ as used herein implies the bulk of the catalyst forms discrete aggregated phase(s) under the reaction conditions, it does not imply that no fraction of the catalyst is soluble

[0349] In addition, since the reaction is heterogeneous and the flakes relatively large (relative to powders), we investigated whether reducing the volume of water in the reaction by50% would bring about significant improvements in efficacy – it was thought that by so reducing the volume of water both hydroxide / catalyst concentration would be doubled while the PET flakes would be in contact with a greater proportion of the bulk solution – and advantageously, the reaction would generate less aqueous waste. Accordingly, we repeated the standard PET hydrolysis with half the volume of aqueous solvent and with only 1 mol% of the benchmark bromide catalyst 17. The result was the isolation of TPA in near quantitative yield after 3 h (Scheme 3).Scheme 3. PET hydrolysis catalysed by 17 under concentrated conditions

[0350] Reaction Protocol for PET hydrolysis at 100 g / L starting concentration of PET

[0351] An oven dried carousel flask was charged with water (5 mL), sodium hydroxide (0.500 g) and catalyst (5 mol %)a. The flask was placed under an atmosphere of nitrogen (balloon), and the reaction was stirred for 20 min at 90 °C. Polyethylene terephthalate flakes (ca. 5 mm squares, 0.500 g) were added and the mixture was stirred (500 RPM) for 3 h. The flask was removed from the carousel and cooled in an ice-bath for 10 min. The reaction mixture was then filtered, and the residue was washed with water (5 mL x 2). The filtrate was adjusted, with cooling, to pH 2-3 using dilute HCl and the resulting precipitate was filtered. The filtrate was washed with water (5 mL) and the product was dried for 4 h in a vacuum oven at 60 ˚C.aMol% of catalyst is related to the number of moles of monomeric units (2.6 mmol) present in 0.500 g of polymer.

[0352] Reaction Protocol for PET hydrolysis at 200 g / L starting concentration of PET

[0353] An oven dried carousel flask was charged with water (2.5 mL), sodium hydroxide (0.500 g, 12.5 mmol) and catalyst 17 (0.0084 g, 0.026 mmol, 1 mol%).aThe flask was placed under an atmosphere of nitrogen (balloon), and the reaction was stirred for 20 min at 90 °C. Polyethylene terephthalate flakes (ca.5 mm squares, 0.500 g) were added and the mixture was stirred (500 RPM) for 3 h. The flask was removed from the carousel and cooled in an ice-bath for 10 min. The reaction mixture was then filtered, and the residue was washed with water (5 mL x2). The filtrate was adjusted, with cooling, to pH 2-3 using dilute HCl and the resulting precipitate was filtered. The filtrate was washed with water (5 mL x 2) and the product was dried for 4 h in a vacuum oven at 60 ˚C. TPA was isolated as a white solid (0.43 g, 99%). M.p.299-301 °C. a Mol% of catalyst is related to the number of moles of monomeric units (2.6 mmol) present in 0.500 g of polymer. δH (400 MHz, DMSO-d6): 13.29 (br s, 2H), 8.04 (s, 4H) ppm. δc (101 MHz, DMSO-d6): 166.6, 134.4, 129.4 ppm. vmax (neat) / cm-1: 2827, 2661, 2546, 1673, 1423, 1278, 928, 726.

[0354] Next, we endeavoured to determine whether altering the temperature, could increase the efficiency of the reaction and indeed whether at higher temperatures whether catalyst solubility would be positively affected. While PET alkaline hydrolysis using elevated pressure and temperature is known, we assessed whether or not we could achieve enhanced alkaline hydrolysis of PET by increasing temperature. The inventors posited that despite using alkaline aqueous conditions, that high solute concentration would increase the boiling point of the aqueous solutions (above 100°C), and it was hoped that such an elevated boiling point would facilitate more efficient and effective alkaline hydrolysis of PET without requiring the application of external pressure. The inventors hypothesized that if sufficient boiling point elevation could be married with compatible and powerful phase-transfer catalysis, significantly accelerated depolymerisation could occur without the need for either co-solvents or high-pressure reactors.

[0355] Initially the effect of temperature on PET alkaline hydrolysis was assessed without the addition of phase transfer catalysts.Scheme 4: Uncatalyzed atmospheric pressure PET alkaline hydrolysis using concentrated NaOH (50%w / v): influence on temperature.

[0356] The hydrolysis of PET flakes cut from waste beverage bottles purchased from a local supermarket (5 mm x 5 mm) using the same loading of NaOH as used previously (PET,NaOH 1:1, 4.8 eq.) was assessed but at a considerably higher base concentration (i.e. an increase from 10% w / v to 50% w / v) in the absence of catalysis.

[0357] At 90°C after 15 min TPA could be isolated after acidification in low yield. However, at atmospheric pressure, the high hydroxide concentrations allowed hydrolysis to occur at temperatures considerably beyond 100°C. A maximum temperature of 138°C was recorded under these conditions, with a yield of TPA of 72% achieved after 15 minutes. As the reaction progresses the boiling temperature decreases from the maximum due to consumption of the base (i.e. NaOH consumption) and concomitant disodium terephthalate precipitation.

[0358] Under the higher base concentration conditions, the effect of PTCs on reaction time and conversion rates was assessed. Phase transfer catalysts were tested at a concentration of 1 mol% loading, and the reaction time was reduced to 10 minutes, which is on par with timescales associated with microwave and co-solvent mediated, high-pressure current industrial processes. Table 8: Evaluation of PTC performance in alkaline PET hydrolysis at elevated temperatureentrycat.time (min) stirring (rpm)[a]cat. solubility[b]yield (%)[c]1 none 10 500 - 51.4 2 42 10 500 soluble 55.4 3 43 10 500 soluble 57.8 4 43a 10 500 soluble 59.4 5 45 10 500 insoluble solid 70.4 6 36 10 500 insoluble oil 69.2 7 17 10 500 soluble 89.2 8 18 10 500 insoluble oil 99.9 9 18a 10 500 insoluble oil 98.1 10 19 10 500 insoluble oil 98.5 11 20 10 500 insoluble oil 58.6 12 7 10 500 soluble 90.4 13 18 5 1000 insoluble oil 90.2 14 18a 5 1000 insoluble oil 89.5 15 19 5 1000 insoluble oil 99.9 16 19 4 1000 insoluble oil 99.9 17 19 3.5 1000 Insoluble oil 96.7 18 none 4 1000 - 29.5 19[d]none 13 1000 - 99.9[a]Revolutions per minute.[b]Refers to solubility under the reaction conditions at 138 ⁰C.[c]Isolated yield.[d]60% NaOH (w / v), 145 °C (the initial temperature at low conversion – the solution boiling point reduces as the hydroxide reacts due to precipitation of Na2TPA).

[0359] As shown in Table 8, symmetrical, 2-chain and 3-chain PTCs were assessed in alkaline PET hydrolysis at high base concentration and elevated temperature and 1 mol% loading. As was the case at lower temperatures, the 2-chain PTCs once again outperformed the other PTCs.

[0360] To both challenge the catalysts and facilitate comparisons, the reaction time was reduced to 10 min – on a par with timescales associated with a microwave- and cosolvent- mediated, high-pressure current industrial process. In the absence of catalyst, ca.50% yield is obtained (entry 1). The soluble dibutyldibenzyl ammonium salt 42 and its dihexyl analogue 43 (a highly efficacious catalyst at 90 ⁰C under more dilute conditions had limited efficacy under the more concentrated conditions at elevated temperature (entries 2-3).

[0361] While exchange of the bromide counterion for chloride (i.e.43a, entry 4) made little difference, the presence of an extended p-system (i.e.45 & 46, entries 5-6) led to appreciable improvements in activity. Dimethyldialkylammonium salts proved outstanding in the more alkaline conditions (~50% NaOH). The diheptyl system 17 (entry 7) proved capable of significant activity, while its immediate homologues 18 and 18a mediated hydrolysis to either near- or full completion (entries 8-9). As outlined above, 17 proved to be the most powerful promoter in 10% NaOH but higher homologues became insoluble in the reaction medium, and resulted in less effective catalysis as alkyl chain length increased Intriguingly here 18 & 18a are insoluble, yet superior to the soluble 17. Given that under these conditions catalyst insolubility was no longer a predictor of reduced activity, the higher homologues 19 and 20 were evaluated. The former species proved an active catalyst (entry 10), while the depolymerisation was clearly promoted more slowly by the larger 20 (entry 11). It is noteworthy that the most active previously identified member of the symmetrical tetraalkylammonium halide catalyst family (i.e.7, entry 12) remains inferior to 18, 18a and 19 here despite being a soluble, constitutional isomer of 19.

[0362] To allow the relative performance of 18-19 to be more easily assessed, depolymerisations involving these catalysts were repeated with a 5 min reaction time and an increase in the stirring speed to 1000 rpm to prevent excessive adherence of hydrolysed product disodium terephthalate to the PET flakes - which allowed the superiority of 19 to be clearly identified (entries 13-15). Further experimentation revealed that 4 min (note – this includes the ramp time required to heat from ambient temperature to 138 ˚C) reaction time is sufficient for essentially quantitative generation of TPA (entries 16-17). This is an unprecedented depolymerisation rate for a simple alkaline PET hydrolysis process without pressure, cosolvent or microwave irradiation. Without catalyst, <30% yield of product is obtained after 4 min (entry 18), however use of a 60% w / v NaOH solution (without altering hydroxide loading) allows hydrolysis at 145˚C - under these conditions after 13 min the uncatalysed recycling is complete (entry 19). However, the use of PTCs at 145 ˚C were less effective.

[0363] Under dilute conditions lipophilic soluble catalysts outperform insoluble homologues, however the faster hydrolysis catalysed by 19 is ascribable to physical contact with the PET flakes in the reaction vessel. PET is denser than water (1.4 g / mL), and the phase transfer catalysts generally have densities <1 g / mL. Under dilute conditions, insoluble phase transfer catalysts tend to accumulate at the top of the solution, while the PET sinks to the bottom, leadingto reduced contact between the two even with vigorous stirring. The depolymerisations reported here occur in 2mL H2O / g PET. The plastic floats more easily in the denser ~50% NaOH solution alongside the insoluble catalyst, leading to improved surface contact. In addition, the solvent generally just covers the insoluble PET in the reaction vessel, so that any insoluble catalyst floating at the top of the solution remains in contact with the PET, especially at low conversions.

[0364] The depolymerisation was also carried out on multigram scale using standard laboratory apparatus. Heat transfer to a flask in an open oil bath was inferior to that associated with the carousel reactor, leading to increased ramp times. To obviate this problem (unlikely to be an issue using heated industrial reactors) PET was added to preheated aqueous NaOH. To avoid potential complications stemming from PET addition at reflux, a marginally lower reactiontemperature of 135̊ C was selected. Otherwise, conditions were identical to those utilised in Table8. A 95% isolated yield of TPA was achieved after 5 min.

[0365] The inventors also assessed whether alkaline hydrolysis of PET textiles could be achieved under similar conditions (see Table 9). Table 9: PTC catalysed alkaline hydrolysis of PET textiles.Entry time (min) X (mL) yield (%)[a]1 15 2 99.9 2 3 4 93.4 3 4 4 99.9[a]Isolated yield.

[0366] Advantageously, the present invention provides a high yielding method for depolymerizing PET or polymers comprising PET units to produce TPA. The method is carried out efficiently at a high concentration of PET, and using comparatively large PET flakes in comparison to those used in prior art methods. The method also works very well with PET textiles. The present method is advantageously scalable, and less environmentally impactful than prior art methods, particularly, having less water waste than many prior art methods.

[0367] Next, the inventors assessed the efficacy of phase transfer catalysts in the alkaline hydrolysis of poly(bisphenol A carbonate).

[0368] Compact discs (CDs) were pre-treated to remove the aluminum layer and the resulting polycarbonate discs were cut into 2.5 mm squares and subjected to the hydrolysis conditions at 135 ˚C as shown below in Table 10. In the absence of catalyst, BPA-PC is remarkably resistant to hydrolysis after 15 min reaction time (entry 1). This may be attributable to the greater hydrophobicity and higher Tg(>140 ˚C) associated with this polymer relative to PET. Appreciable degradation occurs in the presence of 1 mol% of either catalysts 17, 18 or 19, with the dioctyl variant 18 proving superior (entries 2-4). Further optimization allowed the formation of BPA in >90% yield after 30 min reaction time using a 65% (w / v) NaOH solution (entries 5-8). The more concentrated solution permits reaction at 145 ˚C – here depolymerisation in >90% yield requires only 20 min (entry 9).

[0369] Table 10 shows catalyst screening for alkaline hydrolysis of BPA-PC Table 10: Catalyst screening for alkaline hydrolysis of BPA-PC[NaOH] soln. vol time temp. conversion yield entry cat. (% w / v) (mL)[a](min) (⁰C)[b](%)[c](%)[d]1 none 50 2 15 135 14.7 15.0 (14.8) 2 17 50 2 15 135 46.7 46.7 (46.6) 3 18 50 2 15 135 53.2 53.1 (53.2) 4 19 50 2 15 135 33.4 33.5 (33.4) 5 18 50 2 30 135 72.5 72.5 (72.3) 6 18 65 2 20 135 80.2 80.3 (80.0) 7 18 65 3 20 135 86.7 86.8 (86.5) 8 18 65 3 30 135 91.8 92.0 (91.6) 9 18 65 3 20 145 90.4 90.2 (90.2)[a]Refers to the volume of H2O used in the sodium hydroxide solution.[b]Refers to the initial temperature at low conversion – the solution boiling point reduces as the hydroxide reacts due to precipitation of Na2BPA. [c]Calculated based on unreacted BPA-PC. [d]Isolated yield. The value in parenthesis is determined by1H NMR spectroscopy using 4- iodoanisole as an internal standard.

[0370] The properties of recycled PET can be considerably enhanced by blending it with poly (bisphenol A carbonate) (BPA-PC). BPA-PC is a commodity thermoplastic which accounts for about 1% of global plastic production.

[0371] As the phase transfer catalysts described herein, particularly the 2-chain catalysts, effectively catalysed alkaline hydrolysis of both PET and BPA-PC, the present inventors posited that the catalysts may be suitable for conducting a ‘one-por’ catalytic alkaline hydrolysis process involving rapid depolymerization of BPA-PC?PET mixtures to Na2-TPA and Na2-BPA, followed by pH-driven selective protonolysis to allow the sequential precipitation and isolation of the hydrophobic monomers BPA and TPA.

[0372] Accordingly, equimolar amounts of PET bottle and BPA-PC CD waste were hydrolyzed under alkaline conditions using catalyst 18 (1 mol%) at 145 ⁰C using 65% (w / v) NaOH at atmospheric pressure. Cleavage of all ester and carbonate moieties was complete in 30 min. In contrast to methods involving organic solvent - where PC-PBA is the more reactive polymer - here PET hydrolyses first in a matter of minutes, followed by degradation of BPA-PC. Upon reaction completion, addition of water and adjustment of the pH to 7.9 resulted in the precipitation of pure BPA in 90% yield, which was removed by filtration. Notably, no decomposition of BPA was observed. The filtrate was subsequently acidified to pH 2.0, allowing the precipitation of TPA in near quantitative yield. The TPA monomer contained 0.1% BPA. If required, this can be removed by washing with a small amount of ethanol (recoverable by distillation).Scheme 4. Mixed stream PET / BPA-PC waste hydrolysis and selective precipitation

[0373] Advantageously, the inventors have developed novel methodologies for efficient alkaline hydrolysis of polymers, specifically PET and BPA-PC, and for mixed stream plastics including PET and BPA-PC.

[0374] Synthesis of Compound 11:methylamine (2.0 mL, 2.0 M in THF, 4.0 mmol), acetonitrile (4 mL) and potassium carbonate (2.21g, 16 mmol).1-Bromohexane (1.6 mL, 14.0 mmol) was added dropwise at room temperature. The flask was equipped with a condenser and the solution was heated under reflux for 24 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 12 as a brown oil (0.53 g, 37%). δH (400 MHz, DMSO-d6): 3.23-3.13 (m, 6H), 2.93 (s, 3H), 1.69-1.53 (m, 6H), 1.39-1.21 (m, 18H), 0.88 (t, J = 6.3 Hz, 9H) ppm. δC(101 MHz, DMSO-d6): 60.5, 47.5, 30.6, 25.4, 21.8, 21.3, 13.8 ppm. HRMS (m / z – ESI+): Found: 284.3319 (M+) C19H42N+Requires: 284.3312. vmax (neat) / cm-1: 2955, 2926, 2859, 1464, 1379, 1058, 939, 877, 728.

[0378] A 25 mL round-bottomed flask equipped with a stirring bar was charged with trioctylphosphine (1.34 mL, 3.0 mmol) and acetonitrile (3 mL). Iodomethane (0.31 mL, 5.0 mmol) was added dropwise at 0 ºC. The reaction mixture was stirred at room temperature for 1 h. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 14 as a colourless gum (1.31 g, 85%). Spectral data for this compound were consistent with those in literature.2δH(400 MHz, CDCl3): 2.50-2.43 (m, 6H), 2.11 (d, J = 13.3 Hz, 3H), 1.62-1.41 (m, 12H), 1.38-1.17 (m, 24H), 0.86 (t, J = 6.6 Hz, 9H) ppm. δP (162 MHz, CDCl3): 31.2 ppm. HRMS (m / z – ESI+): Found: 385.3965 (M+) C25H54P+Requires: 385.3958. vmax(neat) / cm-1: 2955, 2923, 2855, 1459, 1306, 906, 720.

[0379] Synthesis of Compound 16:mmol). Iodomethane (1.6 mL, 25.7 mmol) was added dropwise at 0 ºC. The reaction mixture was stirred at room temperature for 30 min before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 16 as an off-white solid (1.51 g, 69%). M.p.58-62 °C. δH (400 MHz, DMSO-d6): 3.26 – 3.22 (m, 4H), 3.00 (s, 6H), 1.73 – 1.57 (m, 4H), 1.40 – 1.22 (m, 12H), 0.89 (t, J = 6.4 Hz, 6H) ppm. δc(101 MHz, DMSO-d6): 62.9, 49.9, 30.6, 25.4, 21.8, 21.6, 13.8 ppm. HRMS (m / z – ESI+): Found: 214.2532 (M+) C14H32N+Requires: 214.2529. vmax (neat) / cm-1: 3003, 2955, 2925, 2858, 1483, 1467, 936, 885, 727.temperature. The flask was equipped with a condenser and the solution was heated under reflux for 24 h before the mixture was filtered. The solvent was removed under reduced pressure andthe product was triturated in diethyl ether. The product was dried in vacuo yielding 17 as a colourless gum (1.41 g, 73%). δH(400 MHz, DMSO-d6): 3.26 – 3.18 (m, 4H), 2.98 (s, 6H), 1.70 – 1.57 (m, 4H), 1.37 – 1.19 (m, 16H), 0.87 (t, J = 6.3 Hz, 6H) ppm. δH (101 MHz, DMSO-d6): 62.9, 49.9, 31.0, 28.1, 25.7, 21.9, 21.6, 13.9 ppm. HRMS (m / z – ESI+): Found: 242.2844 (M+) C16H36N+Requires: 242.2842. vmax(neat) / cm-1: 3011, 2924, 2858, 1467, 1275, 904, 729, 697.

[0383] Synthesis of Compound 19

[0384] A 25 mL round bottom flask equipped with a stirring bar was charged with dimethylamine (2.0 mL, 2.0 M in THF, 4.0 mmol), acetonitrile (4 mL) and potassium carbonate (2.21 g, 16.0 mmol).1-Bromononane (2.7 mL, 14.1 mmol) was added and the solution was stirred at room temperature for 16 h before the mixture was filtered and the filtrate was dried in vacuo. The product was purified by flash column chromatography (CH2Cl2 to CH2Cl2 / MeOH (95:5)) to afford 19 as a yellow oil (0.271 g, 20% yield). δH (400 MHz, CDCl3): 3.56-3.47 (m, 4H), 3.40 (s, 6H), 1.77-1.63 (m, 4H), 1.48-1.18 (m, 24H), 0.88 (t, J = 7.0 Hz, 6H) ppm. δC (400 MHz, CDCl3): 64.1, 51.4, 31.9, 29.4, 29.3, 29.2, 26.4, 22.9, 22.7, 14.2 ppm. HRMS (m / z -ES): Found: 289.3468 (M+) C20H44N+Requires: 298.3468. vmax (neat) / cm-1: 2922, 2854, 1467, 927, 722.

[0385] Synthesis of Compound 20

[0386] A 25 mL round bottomed flask was charged with acetonitrile (2 mL), dimethylamine (2.0 mL, 2.0 M solution in THF, 4.0 mmol) and potassium carbonate (2.21 g, 16.0 mmol).1-Bromoundecane (3.12 mL, 14.0 mmol) was diluted with anhydrous acetonitrile (2 mL) and added dropwise to the reaction mixture at room temperature. The flask was equipped with a condenser and the solution was heated under reflux for 24 h before the mixture was filtered. The residual white solid was washed with acetonitrile (3 x 5 mL) and the filtrate was concentrated under reduced pressure. The resulting oil was purified by flash chromatography (CH2Cl2to CH2Cl2 / MeOH (9:1)) to yield 20 as a white solid (1.14 g, 66%). M.p.159-161 °C. δH (400 MHz, CDCl3): 3.57-3.46 (m, 4H), 3.41 (s, 6H), 1.74-1.63 (m, 4H), 1.43-1.20 (m, 32H), 0.87 (t, 6H, J = 6.8 Hz) ppm. δC(100 MHz, CDCl3): 64.0, 51.4, 32.0, 29.7, 29.6, 29.5, 29.4, 29.3, 26.4, 22.9, 22.8, 14.2 ppm. HRMS (m / z – ESI+): Found: 354.4098 (M+) C24H52N+Requires: 354.4094. νmax (neat) / cm-1: 2951, 2921, 2853, 1466, 1455, 889, 720.

[0388] A 25 mL round bottom flask equipped with a stirring bar was charged with triethylamine (1.4 mL, 10.0 mmol), THF (5 mL) and benzyl bromide (0.6 g, 5.1 mmol). The reaction mixture was stirred at room temperature for 48 h and the resulting precipitate was filtered. The solid was dissolved in the minimum volume of CH2Cl2before being added to ice cold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 X 5 mL) and dried in vacuo to give 31 as a white solid (1.21 g, 89%). M.p.196-198 °C.δH (400 MHz, CDCl3): 7.53-7.28 (m, 5H), 4.67 (s, 2H), 3.35 (q, J = 7.2 Hz, 6H), 1.36 (t, J = 7.2 Hz, 9H) ppm. δC(101 MHz, CDCl3): 132.4, 130.6, 129.3, 127.1, 61.3, 52.9, 8.6 ppm. HRMS (m / z – ESI+): Found: 192.1748 (M+) C13H22N+Requires: 192.1747.mixture was stirred at room temperature for 48 h and the resulting precipitate was filtered. The solid was dissolved in the minimum volume of CH2Cl2 before being added to ice cold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 x 5 mL) and dried in vacuo to give 32 as a white solid (1.67 g, 93%). δH(400 MHz, DMSO-d6): 7.54-7.48 (m, 5H), 4.52 (s, 2H), 3.12-3.05 (m, 6H), 1.77-1.66 (m, 6H), 1.36-1.26 (m, 6H), 0.95 (t, J = 7.5 Hz, 9H) ppm. δC (101 MHz, DMSO-d6): 132.5, 130.4, 129.1, 127.8, 61.2, 57.5, 23.3, 19.2, 13.5 ppm. HRMS (m / z – ESI+): Found: 276.2686 (M+) C19H34N+Requires: 276.2686. νmax(neat) / cm-1: 2960, 2872, 1476, 1458, 723, 702.

[0391] Synthesis of Compound 33:

[0392] A 50 mL round bottomed flask was charged with anhydrous acetonitrile (10 mL) and tributylphosphine (2.02 g, 10.0 mmol). The emulsion was kept under an argon atmosphere, stirred vigorously for 5 min, and cooled to 0 °C. Benzyl bromide (1.54 g, 9.0 mmol) was added dropwise to the emulsion and the resulting mixture was stirred at room temperature for 16 h. The crude mixture was evaporated under reduced pressure. Diethyl ether (30 mL) was added and the resulting mixture was filtered. The solid was washed with diethyl ether (3 x 20 mL) to yield 33 as a white solid (3.28 g, 98%). M.p.143.0-144.0 °C. (Lit.,2143 °C) Spectral data for this compound were consistent with those in literature.4was filtered. The solid was dissolved in the minimum volume of CH2Cl2 before being added to icecold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 x 5 mL) and dried in vacuo to give 34 as a white solid (1.67 g, 82%). M.p.120-121 °C δH(600 MHz, DMSO-d6): 8.09-8.05 (m, 2H), 8.03-7.98 (m, 2H), 7.67-7.60 (m, 2H), 7.57 (dd, J = 8.4, 1.7 Hz, 1H), 4.69 (s, 2H), 3.20-3.09 (m, 6H), 1.83-1.72 (m, 6H), 1.39 – 1.30 (m, 6H), 0.96 (t, J = 7.4 Hz, 9H) ppm. δC(151 MHz, DMSO-d6): 133.3, 132.9, 132.5, 128.9, 128.6, 128.3, 127.7, 127.6, 127.0, 125.3, 61.3, 57.5, 23.3, 19.3, 13.5 ppm. HRMS (m / z – ESI+): Found: 326.2849 (M+) C23H36N+ Requires: 326.2842. νmax (neat) / cm-1: 2963, 2935, 2875, 1969, 1815, 1485, 840, 788, 771.

[0396] A 25 mL round bottomed flask was charged with anhydrous acetonitrile (3 mL) and tributylphosphine (1.01 g, 5.0 mmol). The emulsion was kept under an argon atmosphere, stirred vigorously for 5 min, and cooled to 0 °C.1-(Bromomethyl)naphthalene (1.11 g, 5.0 mmol) was dissolved in anhydrous acetonitrile (2 mL), added dropwise to the emulsion and the resulting mixture was stirred at room temperature for 16 h. The crude mixture was evaporated under reduced pressure. Diethyl ether (15 mL) was added to initiate product precipitation. The product was filtered and the resulting solid was washed with diethyl ether (3 x 10 mL) to yield 35 as a white solid (1.64 g, 86%). M.p.100-102 °C. δH (600 MHz, DMSO-d6): 8.03-7.87 (m, 4H), 7.61-7.52 (m, 2H), 7.52-7.44 (m, 1H), 4.01 (d, J = 15.5 Hz, 2H), 2.27-2.12 (m, 6H), 1.53-1.30 (m, 12H), 0.87 (t, J = 7.2 Hz, 9H) ppm. δC(151 MHz, DMSO-d6): 132.9 (d, J = 2.9 Hz), 132.2 (d, J = 2.5 Hz), 128.9 (d, J = 6.5 Hz), 128.8 (d, J = 2.3 Hz), 127.7, 127.6 (d, J = 3.9 Hz), 127.5, 126.9, 126.8, 126.5, 25.6 (d, J = 44.2 Hz), 23.3 (d, J =15.7 Hz), 22.5 (d, J = 4.5 Hz) , 17.4 (d, J = 46.8 Hz), 13.2 ppm. δP (162 MHz, DMSO-d6): 33.0 ppm.HRMS (m / z – ESI+): Found: 343.2551 (M+) C23H36P+Requires: 343.2549. νmax(neat) / cm-1: 2957, 2929, 2871, 1465, 1094, 917, 861, 828, 744.

[0397] Synthesis of Compound 36:

[0398] A 25 mL round bottom flask equipped with a stirring bar was charged with tributylamine (3.0 mL, 12.6 mmol), THF (5 mL) and (2-bromomethyl)naphthalene (1.11 g, 5.0 mmol). The reaction mixture was stirred at room temperature for 24 h and the resulting precipitate was filtered. The solid was dissolved in the minimum volume of CH2Cl2 before being added to ice cold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 X 5 mL) and dried in vacuo to give 36 as a white solid (1.01 g, 49%). M.p.137-139 °C. δH (600 MHz, DMSO-d6): 8.08-7.97 (m, 4H), 7.66-7.54 (m, 3H), 4.68 (s, 2H), 3.18-3.09 (m, 6H), 1.81-1.71 (m, 6H), 1.37-1.28 (m, 6H), 0.94 (t, J = 7.7 Hz, 9H) ppm. δC (151 MHz, DMSO-d6): 133.8, 133.4, 132.9, 128.4, 129.1, 128.7, 128.1, 128.1, 127.5, 128.0, 61.7, 58.0, 23.8, 19.7, 14.0 ppm. HRMS (m / z – ESI+): Found: 326.2850 (M+) C23H36N+Requires: 326.2842. νmax (neat) / cm-1: 2962, 1484, 1371, 840, 787, 771.

[0399] Synthesis of Compound 37:

[0400] A 25 mL round bottom flask equipped with a stirring bar was charged with tributylamine (2.4 mL, 10.1 mmol), THF (5 mL) and 4-(bromomethyl)-1,1’-biphenyl (1.24 g, 5.0 mmol). The reaction mixture was stirred at room temperature for 24 h and the resulting precipitate was filtered. The solid was dissolved in the minimum volume of CH2Cl2 before being added to ice cold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 x 5 mL) and dried in vacuo to give 37 as a white powder (1.01 g, 49%). M.p.158-159 °C. δH(600 MHz, DMSO-d6): 7.87 (m, 2H), 7.75-7.72 (m, 2H), 7.60-7.56 (m, 2H), 7.52-7.48 (m, 2H), 7.44-7.40 (m, 1H), 4.57 (s, 2H), 3.16-3.09 (m, 6H), 1.80-1.70 (m, 6H), 1.38-1.29 (m, 6H), 0.96 (t, J = 7.4 Hz, 9H) ppm. δC(151 MHz, DMSO-d6): 141.8, 138.8, 133.2, 129.1, 128.1, 127.1, 126.9, 126.8, 60.9, 57.5, 23.3, 19.2, 13.5 ppm. HRMS (m / z – ESI+): Found: 352.2999 (M+) C25H38N+Requires: 352.2999. νmax (neat) / cm-1: 2960, 2872, 1483, 1461, 869, 765, 703. of Compound 38:

[0402] A 25 mL round bottom flask equipped with a stirring bar was charged with tributylamine (2.6 mL, 11.1 mmol), THF (5 mL) and 9-(bromomethyl)anthracene (1.00 g, 3.7 mmol). The reaction mixture was stirred at room temperature for 24 h and the resulting precipitate was filtered. The solid was dissolved in the minimum volume of CH2Cl2before being added to ice cold diethyl ether. The resulting suspension was filtered and the solid was washed with diethyl ether (3 x 5 mL) and dried in vacuo to give 38 as a white powder (1.43 g, 79%). M.p.137-139 °C. δH(600 MHz, DMSO-d6): 8.93 (s, 1H), 8.72 (app. d, 2H), 8.23 (app. d, 2H), 7.73 (app. t, J = 8.2 Hz, 2H), 7.63 (app. t, J = 7.7 Hz, 2H), 5.73 (s, 2H), 3.4-3.28 (m, 6H), 1.28-1.14 (m, 6H), 0.96 (m, 6H), 0.67 (t, J = 7.3 Hz, 9H) ppm. δC (151 MHz, DMSO-d6):132.4, 131.5, 130.9, 129.4, 127.5, 125.7, 124.4, 120.6, 60.0, 58.4, 24.0, 19.2, 13.1 ppm.HRMS (m / z – ESI+): Found: 376.2999 (M+) C27H38N+Requires: 376.2999. νmax(neat) / cm-1: 2959, 2873, 1467, 1378, 858, 746.

[0403] Synthesis of Compound 39:

[0404] A 25 mL round bottomed flask under argon atmosphere, equipped with a stirring bar, was charged with acetonitrile (3 mL), potassium carbonate (0.70 g, 5.1 mmol) and tetrahydroisoquinoline (0.32 mL, 2.5 mmol). 1-Bromooctane (0.70 mL, 4.0 mmol) was added dropwise. The flask was equipped with a condenser and the solution was heated under reflux for 16 h. After cooling to room temperature, the solution was filtered and the filtrate was concentrated under reduced pressure. The resulting yellow oil was then dissolved in CH2Cl2(1 mL) before being added dropwise to ice cold diethyl ether (15 mL) yielding a yellow precipitate. The product was purified by flash column chromatography (CH2Cl2 to CH2Cl2 / MeOH (95:5)) to afford 39 as a white solid (0.184 g, 17% yield). M.p.144-146 °C. δH(600 MHz, DMSO-d6): 7.38-7.28 (m, 3H), 7.20 (app.d, 1H), 4.61 (s, 2H), 3.69 (t, J = 6.3 Hz, 2H), 3.29-3.22 (m, 4H), 3.13 (t, J = 6.3 Hz, 2H), 1.76-1.66 (m, 4H), 1.35-1.20 (m, 20H), 0.87 (t, J = 6.7 Hz, 6H) ppm. δC (151 MHz, DMSO-d6): 130.7, 129.3, 128.6, 127.6, 127.5, 127.5, 60.4, 58.2, 55.5, 31.6, 28.9, 26.2, 23.5, 22.5, 22.5, 21.4, 14.4 ppm. HRMS (m / z -ESI+): Found: 358.3476 (M+) C25H44N+Requires: 358.3468. vmax (neat) / cm-1: 2955, 2923, 2854, 1494, 1453, 748, 724.

[0405] Synthesis of Compound 40:mL round-bottomed flask equipped with a stirring bar was charged with mL, 2.0 M in THF, 5.0 mmol), acetonitrile (5 mL) and potassium carbonate . Benzyl bromide (1.78 mL, 15.0 mmol) was added dropwise at room mixture was stirred for 24 h before the mixture was filtered. The solvent reduced pressure and the product was triturated in diethyl ether. The product 40 as a white solid (1.45 g, 95%). M.p.196-198 °C. d6): 7.66-7.48 (m, 10H), 4.62 (s, 4H), 2.87 (s, 6H) ppm. d6): 133.1, 130.2, 128.9, 128.1, 66.7, 48.0 ppm. Found: 226.1594 (M+) C16H20N+Requires: 226.1590. 2960, 2854, 2013, 1827, 1495, 847, 757, 731. of Compound 41: dipropyldibenzyl ammonium bromide mL round-bottomed flask equipped with a stirring bar was charged with dipropylamine (0.69 mL, 5.0 mmol), acetonitrile (5 mL) and potassium carbonate (1.73 g, 12.5 mmol). Benzyl bromide (1.34 mL, 11.3 mmol) was added dropwise at room temperature. The reaction mixture was stirred for 48 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 41 as a white solid (1.31 g, 72%). M.p.159-160 °C. δH(400 MHz, DMSO-d6): 7.65-7.48 (m, 10H), 4.64 (s, 4H), 3.15-3.03 (m, 4H), 1.89-1.74 (m, 4H), 0.84 (t, J = 7.1 Hz, 6H) ppm. δC (101 MHz, DMSO-d6): 132.8, 130.2, 129.0, 128.1, 62.8, 58.8, 15.8, 10.4 ppm.HRMS (m / z – ESI+): Found: 282.2220 (M+) C20H28N+Requires: 282.2216. vmax(neat) / cm-1: 2988, 2962, 2876, 1473, 1460, 963, 743, 729, 702.

[0409] Synthesis of Compound 42:

[0410] A 25 mL round-bottomed flask equipped with a stirring bar was charged with dibutylamine (0.84 mL, 5.0 mmol), acetonitrile (5 mL) and potassium carbonate (1.728 g, 12.5 mmol). Benzyl bromide (1.48 mL, 12.5 mmol) was added dropwise at room temperature. The reaction mixture was stirred for 48 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 42 as a white solid (1.72 g, 88%). M.p.140-141 °C. δH (400 MHz, DMSO-d6): 7.64-7.47 (m, 10H), 4.60 (s, 4H), 3.16-3.05 (m, 4H), 1.86-1.72 (m, 4H), 1.34-1.18 (m, 4H), 0.90 (t, J = 7.4 Hz, 6H) ppm. δC(101 MHz, DMSO-d6): 132.9, 130.3, 129.1, 128.0, 62.8, 57.4, 23.9, 19.3, 13.5 ppm. HRMS (m / z – ESI+): Found: 310.2529 (M+) C22H32N+Requires: 310.2529. vmax (neat) / cm-1: 2955, 2868, 1498, 1476, 872, 756, 725.

[0411] Synthesis of Compound 43:

[0412] A 25 mL round-bottomed flask equipped with a stirring bar was charged with dihexylamine (0.93 mL, 7.1 mmol), acetonitrile (5 mL) and potassium carbonate (1.73 g, 12.5 mmol). Benzyl bromide (1.92 mL, 16.1 mmol) was added dropwise at room temperature. The reaction mixture was stirred for 48 h before the mixture was filtered. The solvent was removeddimethylamine (2.53 mL, 2.0 M in THF, 5.1 mmol), acetonitrile (5 mL) and potassium carbonate (2.07 g, 15.0 mmol).2-(bromomethyl)naphthalene (2.76 mL, 12.5 mmol) was added dropwise at room temperature. The reaction mixture was stirred for 24 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 44 as a white solid (0.166 g, 8%). M.p.228-230 °C. δH (400 MHz, DMSO-d6): 8.21 (s, 2H), 8.1-7.94 (m, 6H), 7.70 (d, J = 8.2, 2H), 7.66-7.57 (m, 4H), 4.87 (s, 4H), 3.00 (s, 6H) ppm. δC(101 MHz, DMSO-d6): 133.4, 133.3, 132.5, 129.6, 128.4, 128.3, 127.6, 127.5, 126.8, 125.5, 67.2, 48.4 ppm. HRMS (m / z – ESI+): Found: 326.1903 (M+) C24H24N+Requires: 326.1903. vmax (neat) / cm-1: 3030, 2961, 2868, 1487, 1474, 860, 819, 782.

[0415] Synthesis of Compound 45:(0.28 g, 2.0 mmol). 4-(bromomethyl)-1,1’-biphenyl (0.50 g, 2.0 mmol) was added dropwise at room temperature. The reaction mixture was stirred at reflux for 24 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 45 as a white solid (0.492 g, 80%). M.p. 230-232 °C. δH (400 MHz, DMSO-d6): 7.83 (d, J = 8.0 Hz, 4H), 7.79 – 7.69 (m, 8H), 7.49 (app. t, J = 7.5 Hz, 4H), 7.43-7.41 (t, J = 7.2 Hz, 2H), 4.83 (s, 4H), 2.99 (s, 6H) ppm. δC(101 MHz, DMSO-d6): 141.7, 139.0, 133.8, 129.0, 128.0, 127.2, 127.0, 126.8, 66.4, 48.1 ppm. HRMS (m / z – ESI+): Found: 378.2220 (M+) C28H28N+Requires: 378.2216.mmol). (2-bromomethyl)naphthalene (2.76 g, 12.5 mmol) was added dropwise at room temperature. The reaction mixture was stirred for 48 h before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 46 as a white solid (0.26 g, 11%). M.p.166-167 °C. δH (400 MHz, DMSO-d6): 8.22 (s, 2H), 8.07 (d, J = 8.6 Hz, 2H), 8.01 (t, J = 7.8 Hz, 4H), 7.71 (d, J = 8.6 Hz, 2H), 7.68-7.58 (m, 4H), 4.87 (s, 4H), 3.28-3.20 (m, 4H), 2.00-1.82 (m, 4H), 1.39-1.22 (m, 4H), 0.92 (t, J = 7.3 Hz, 6H) ppm. δC (101 MHz, DMSO-d6): 133.4, 133.3, 132.5, 129.4, 128.5, 128.3, 127.58, 127.57126.9, 125.5, 62.9, 57.4, 24.0, 19.4, 13.4 ppm. HRMS (m / z – ESI+): Found: 410.2848 (M+) C30H36N+Requires: 410.2842. vmax(neat) / cm-1: 3049, 2961, 2871, 2164, 1982, 1474, 1365, 762.

[0419] Synthesis of Compound 47:A 50 mL round-bottomed flask equipped with a stirring bar was charged with N,N- dimethyl-aniline (0.63 mL, 5.0 mmol) and CH2Cl2(5 mL). Iodomethane (0.31 mL, 5.0 mmol) was added dropwise at 0 ºC. The reaction mixture was stirred at room temperature for 24 h. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 47 as an off-white solid (0.47 g, 36%). M.p.220-221 °C. (lit. M.p.222-223)4. δH (400 MHz, CDCl3):7.87 (d, J = 8.3 Hz, 2H), 7.70-7.62 (m, 2H), 7.62-7.55 (m, 1H), 4.02 (s, 9H) ppm. δC(101 MHz, CDCl3): 147.3, 131.1, 131.0, 119.8, 57.9 ppm. HRMS (m / z – ESI+): Found: 136.1120 (M+) C9H14N+Requires: 136.1121. vmax (neat) / cm-1: 3009, 1743, 1593, 1498, 1460, 939, 841, 765, 691.

[0421] Synthesis of Compound 48:

[0422] A 100mL round bottomed flask under argon atmosphere, equipped with a stirring bar, was charged with anhydrous pyridine (0.40 mL, 5.0 mmol) and acetonitrile (50 mL). Methyl iodide (0.31 mL, 5.0 mmol) was added dropwise and the mixture was refluxed for 18 h before being concentrated under reduced pressure. The resulting yellow solid was then dissolved in acetonitrile (7 mL) and was added to a stirring solution of diethyl ether (20 mL) before being filtered and washed with diethyl ether (3 x 10 mL) yielding 48 as a light-yellow solid (0.97 g, 88%). M.p. 79-80 °C dec. δH (400 MHz, DMSO-d6): 8.99 (d, J = 5.6 Hz, 2H), 8.58 (t, J = 7.8 Hz, 1H), 8.14 (app. t, 2H), 4.36 (s, 3H) ppm. δC(101 MHz, DMSO-d6): 145.5, 145.04, 127.7, 47.9 ppm. HRMS (m / z – ESI+): Found: 94.0651 (M+) C6H8N+Requires: 94.0651. 1284, 766, 673.

[0424] A 25 mL round bottomed flask under argon atmosphere, equipped with a stirring bar, was charged with anhydrous pyridine (1.05 mL, 13.0 mmol).1-bromooctane (2.25 mL, 13.0 mmol) was added and the mixture was heated to 80 ºC for 3 h. The mixture was concentrated under reduced pressure. The resulting yellow oil was triturated in diethyl ether (3 x 10 mL) yielding 49 as a light-yellow oil (1.23 g, 35%).δH (600 MHz, DMSO-d6): 9.12 (d, J = 5.3 Hz, 2H), 8.61 (t, J = 7.8 Hz, 1H), 8.14 (app. t, 2H), 4.60 (t, J = 7.2 Hz, 2H), 1.99-1.83 (m, 2H), 1.38-1.14 (m, 10H), 0.85 (t, J = 8.3 Hz, 3H) ppm. δC(151 MHz, DMSO-d6): 145.5, 144.7, 128.1, 60.7, 31.1, 30.7, 28.4, 28.3, 25.4, 22.0, 13.9 ppm. HRMS (m / z – ESI+): Found: 192.1750 (M+) C13H22N+Requires: 192.1747.mmol). Iodomethane (1.17 mL, 18.7 mmol) was added dropwise at 0 ºC. The reaction mixture was stirred at room temperature for 30 min before the mixture was filtered. The solvent was removed under reduced pressure and the product was triturated in diethyl ether. The product was dried in vacuo yielding 52 as an off-white solid (1.46 g, 84%). M.p.66-68 °C. δH (400 MHz, DMSO-d6): 3.24 – 3.20 (m, 4H), 2.98 (s, 6H), 1.68 – 1.55 (m, 4H), 1.36 – 1.16 (m, 16H), 0.85 (t, J = 6.5 Hz, 6H) ppm. δC(101 MHz, DMSO-d6): 62.9, 49.9, 30.9, 28.1, 25.7, 21.9, 21.7, 13.9 ppm. HRMS (m / z – ESI+): Found: 242.2842 (M+) C16H36N+Requires: 242.2842. vmax (neat) / cm-1: 2924, 2856, 1467, 1378, 902, 724.

[0427] Synthesis of Compound 53:

[0428] A 100 mL round-bottomed flask equipped with a stirring bar was charged with Dowex® 1X8 Cl (5.0 g) and methanol (30 mL). N,N-dimethyl-N-octyloctan-1-aminium bromide (18, 0.50 g, 1.43 mmol) was added and the mixture was shaken for 20 h on an orbital shaker. The mixture was passed through a plug of Dowex® 1X8 Cl (5.0 g) and the solvent was removed under reduced pressure. The product was triturated in diethyl ether and dried in vacuo yielding 53 as an off-white solid (0.41 g, 94%). M.p.58-61 °C. δH (400 MHz, DMSO-d6): 3.31-3.21 (m, 4H), 3.02 (s, 6H), 1.71-1.56 (m, 4H), 1.38-1.16 (m, 20H), 0.86 (t, J = 6.5 Hz, 6H) ppm. δC(101 MHz, DMSO-d6): 62.7, 49.8, 31.1, 28.4, 28.4, 25.8, 22.0, 21.6, 13.9 ppm. HRMS (m / z – ESI+): Found: 354.4098 (M+) C24H52N+Requires: 354.4094. vmax (neat) / cm-1: 2998, 2921, 2871, 2854, 1470, 897, 725.

[0429] PET hydrolysis

[0430] TPA isolated from bottle wasteAn oven-dried carousel flask was charged with water (2 mL), sodium hydroxide (1.00 g), catalyst (1 mol %) and poly(ethylene terephthalate) flakes (ca.5 mm squares, 1.00 g).aThe flask was placed under an atmosphere of nitrogen (balloon), and the reaction was stirred (500 RPM) at 138 °C with two stirrer bars for 4 min. The flask was removed from the carousel and cooled in an ice- bath for 10 min. The reaction mixture was diluted with 15 ml water and stirrer at rt until solid sodium terephthalate was dissolved then filtered, and the residue was washed with water (10 mL x 2). The filtrate was adjusted, with cooling, to pH 1-2 using dilute HCl and the resulting precipitate was filtered and washed with water (10 mL x 2). The product was dried for 4 h in a vacuum oven at 60 ˚C. The isolated yield was calculated by general formula (Actual yield / Theoretical Yield) and the NMR yield of terephthalic acid was determined by1H NMR spectroscopy using 4-iodoanisoleas an internal standard: known masses of product (> 15 mg) and 4-iodoanisole (> 15 mg) were weighed into a sample vial and dissolved in DMSO-d6.aNaOH was dried in vacuum oven at 60 °C for 48 h and allowed to cool down under an nitrogen atmosphere. Mol% of catalyst is related to the number of moles of monomeric units (5.2 mmol) present in 1.0 g of polymer. δH(400 MHz, DMSO-d6): 8.48 (s, 1H), 8.16 (d, J = 7.7 Hz, 2H), 7.64 (t, J = 7.7 Hz, 1H)

[0431] PET hydrolysis multi-gram scale

[0432] An oven dried 100 mL round bottomed flask was charged with water (20 mL), sodium hydroxide (10.00 g) and catalyst 10 (196.8 mg, 1 mol %).aThe flask was placed under an atmosphere of nitrogen (balloon), and the reaction was stirred at 135 °C at 1000 RPM using two stirrer bars until the solution reached the set temperature. Poly(ethylene terephthalate) flakes (ca.5 mm squares, 10.00 g) were added and the mixture was stirred for 5 min. The flask was removed from the oil-bath and cooled in an ice-bath for 10 min. The reaction mixture was diluted with water (150 mL) and stirred at rt until solid sodium terephthalate was dissolved. The mixture was then filtered, and the residue was washed with water (50 mL x 2). The filtrate was adjusted, with cooling, to pH 1-2 using dilute HCl and the resulting precipitate was filtered and washed with water (30 mL x 2). The product was dried for 4 h in a vacuum oven at 60 ˚C. TPA was isolated in 95% (8.2 g) yield.1H NMR (400 MHz, DMSO-d6) δ 13.28 (br s, 2H), 8.04 (s, 4H).13C NMR (101 MHz, DMSO-d6) δ 166.7, 134.5, 129.5. HRMS (m / z – ESI+): Found: 165.0192 (M+H) C8H6O4-H Requires: 165.0193aNaOH was dried in vacuum oven at 60 °C for 48 h and allowed to cool down under an nitrogen atmosphere. Mol% of catalyst is related to the number of moles of monomeric units (5.2 mmol) present in 1.0 g of polymer. δH(400 MHz, DMSO-d6): 8.48 (s, 1H), 8.16 (d, J = 7.7 Hz, 2H), 7.64 (t, J = 7.7 Hz, 1H)

[0433] TPA isolated from textile fibre wasteAn oven-dried round bottomed flask (25 mL) was charged with water (2 mL), sodium hydroxide (1.00 g), catalyst 19 (19.68 mg, 1 mol %) and polyethylene terephthalate fibre (ca.5 mm squares, 1.00 g).aThe flask was placed under an N2atmosphere (balloon), and the reaction was stirred(1000 RPM) at 135 °C with two stirrer bars for 15 min. The flask was removed from the oil bath and cooled in an ice-bath for 10 min. The reaction mixture was diluted with 20 mL water and stirrer at rt until solid sodium terephthalate was dissolved. The mixture was filtered, and the residue washed with water (10 mL x 2). The filtrate was adjusted, with cooling, to pH 1-2 using dilute HCl and the resulting precipitate was filtered and washed with water (10 mL x 2). The product was dried for 4 h in a vacuum oven at 60 ˚C. The isolated yield was calculated by general formula (actual yield / theoretical yield) and the NMR yield of terephthalic acid was determined by1H NMR spectroscopy using 4-iodoanisole as an internal standard: known masses of product (> 15 mg) and 4-iodoanisole (> 15 mg) were weighed into a sample vial and dissolved in DMSO-d6. The integrals corresponding to TPA were used to determine yield.1H NMR (400 MHz, DMSO-d6) δ 13.28 (br s, 2H), 8.04 (s, 4H).13C NMR (101 MHz, DMSO-d6) δ 166.7, 134.5, 129.5. HRMS (m / z – ESI+): Found: 165.0192 (M+H) C8H6O4-H Requires: 165.0193aNaOH was dried in vacuum oven at 60 °C for 48 h and cool down under a nitrogen atmosphere of nitrogen. Mol% of catalyst is related to the number of moles of monomeric units (5.2 mmol) present in 1.0 g of polymer.

[0434] Polycarbonate hydrolysis and characterisation: BPA isolated from CDsAn oven-dried round bottomed flask (25 mL) was charged with water (3 mL), sodium hydroxide (1.95 g), catalyst 18 (1 mol%) and poly(bis-phenol A carbonate) flakes (ca.2.5 mm squares, 1.00 g).aThe flask was placed under a nitrogen atmosphere (balloon), and the reaction was stirred (1000 RPM) at 135 °C for 30 min. The flask was removed from the oil bath and cooled in an ice- bath for 10 min. The reaction mixture was diluted with 25 mL water and stirred at rt until the solid disodium salt of bisphenol A was dissolved. The mixture was then filtered, and the residue was washed with water (10 mL x 2). The filtrate was adjusted, with cooling, to pH 7 using dilute HCl and the resulting precipitate was filtered and washed with water (5 mL x 2). The product was dried for 4 h in a vacuum oven at 60 ˚C. The isolated yield was calculated by general formula (actual yield / theoretical yield) and the NMR yield of bisphenol A was determined by1H NMR spectroscopy using 4-iodoanisole as an internal standard: known masses of product (> 15 mg) and 4- iodoanisole (> 15 mg) were weighed into a sample vial and dissolved in DMSO-d6. The integrals corresponding to BPA were used to determine yield. BPA:1H NMR (400 MHz, DMSO-d6) δ 9.11 (s, 2H), 6.97 (d, J = 8.5 Hz, 4H), 6.63 (d, J = 8.5 Hz, 4H), 1.52 (s, 6H).13C NMR (101 MHz, DMSO-d6) δ 154.9, 141.0, 127.2, 114.5, 40.9, 30.9. HRMS (m / z – ESI+): Found: 227.1072 (M+H) C15H15O2- Requires: 227.1078aNaOH was dried in vacuum oven at 60 °C for 48 h and cool down under a nitrogen atmosphere. Mol% of catalyst is related to the number of moles of monomeric units (3.94 mmol) present in 1.0 g of polymer.

[0435] Mixed recycling (PET+PC) and characterisation: An oven-dried round-bottomed flask (25 ml) was charged with water (3 mL), sodium hydroxide (1.95 g), catalyst 8 (13.8 mg, 1 mol %) and polycarbonate flakes (ca.2.5 mm squares, 0.5 g, 1.97 mmol) with polyethylene terephthalate flakes (ca.5 mm squares, 3.5 g, 1.97 mmol).aThe flask was placed under a nitrogen atmosphere (balloon), and the reaction was stirred (1000 RPM) at 145 °C for 30 min. The flask was removed from the oil bath and cooled in an ice-bath for 10 min. The reaction mixture was diluted with 25 mL water and stirred at rt until the solid disodium salts of BPA and TPA dissolved. The mixture was then filtered, and the residue was washed with water (10 mL x 2). The filtrate was diluted with 50 mL water and adjusted, with cooling, to pH 7.9 using dilute HCl and the resulting precipitate was filtered and washed with water (10 mL x 2) to give solid BPA. Then the remaining filtrate was again acidified with dilute HCl till pH 2 and the resulting precipitate was filtered and washed with water (10 mL x 2) to give solid TPA. Both the product was dried for 4 h in a vacuum oven at 60 ˚C. Both the product was characterized and calculate the isolated yield. The isolated BPA was 100% pure; however, the TPA was 99.9% pure, containing <0.1% BPA as an impurity. To obtain 100% pure TPA it was washed with ethanol.aNaOH was dried in vacuum oven at 60 °C for 48 h and cool down under a nitrogen atmosphere. BPA:1H NMR (400 MHz, DMSO-d6) δ 9.11 (s, 2H), 6.97 (d, J = 8.5 Hz, 4H), 6.63 (d, J = 8.5 Hz, 4H), 1.52 (s, 6H).13C NMR (101 MHz, DMSO-d6) δ 154.9, 141.0, 127.2, 114.5, 40.9, 30.9. TPA:1H NMR (400 MHz, DMSO-d6) δ 13.28 (br s, 2H), 8.04 (s, 4H).13C NMR (101 MHz, DMSO-d6) δ 166.7, 134.5, 129.5.

[0436] The words “comprises / comprising” and the words “having / including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0437] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub- combination.Embodiments 1. A method for hydrolysing polyethylene terephthalate comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms; or Formula (II), wherein X3is N, and A3- is an anion, wherein Raand Rbare each independently selected from C2-C8 aliphatic, wherein Rcis selected from C1-C8 aliphatic or C6-C20 aryl, and wherein Rdis C6-C20 aryl, or wherein Rcand Rdtogether form a ring structure having one or more C5-C10 aryl substituents, and wherein a catalyst of formula (II) comprises at least 18 carbon atoms.2. The method of embodiment 1, wherein the catalyst is a phase transfer catalyst of formula (I). 3. The method of embodiment 1 or 2, wherein each of R1and R2are independently C1-C3 alkyl. 4. The method of any preceding embodiment, wherein each of R1and R2are C1alkyl, preferably methyl. 5. The method of any preceding embodiment, wherein each of R3and R4is independently selected from C6-C12 alkyl. 6. The method of any preceding embodiment, wherein R3and R4are the same. 7. The method of any preceding embodiment, wherein R3and R4are C6alkyl, C7alkyl or C8alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, or octyl. 8. The method of any preceding embodiment, wherein R1and R2are methyl. 9. The method of any preceding embodiment, wherein R3and R4are heptyl or octyl, preferably, wherein R3and R4are heptyl. 10. The method of embodiment 1, wherein R1and R2are methyl and R3and R4are heptyl or octyl. 11. The method of embodiment 1, wherein the phase transfer catalyst has formula (II). 12. The method of embodiment 11, wherein each of Raand Rbis independently selected from C2 to C6 aliphatic, optionally, C2 to C6 alkyl. 13. The method of embodiment 12, wherein at least two of Ra, Rband Rcare the same. 14. The method of any one of embodiments 11 to 13, wherein at least two of Ra, Rband Rcare C4-C6aliphatic, optionally, C4-C6alkyl, optionally, butyl, pentyl or hexyl. 15. The method of any one of embodiments 11 to 14, wherein Rdis C6-C12 aryl. 16. The method of any one of embodiments 11 to 15, wherein Rdis selected from phenyl, biphenyl and naphthyl. 17. The method of any one of embodiments 11 to 16, wherein Raand Rbare butyl, and wherein Rdis phenyl or biphenyl.18. The method of embodiment 17, wherein Rcis butyl, optionally, wherein Rcis butyl and Rdis biphenyl. (compound 37) 19. The method of any one of embodiments 11 to 13 wherein Rcand Rdare each independently C6-C12 aryl, optionally, selected from phenyl, naphthyl or biphenyl. 20. The method of embodiment 19, wherein Raand Rbare each independently C4-C6 alkyl, optionally, selected from butyl, pentyl or hexyl. 21. The method of embodiment 19 or 20, wherein Raand Rbare each butyl or hexyl, and Rcand Rdare phenyl (compound 42 and 43) or Rcand Rdare each naphthyl (compound 45). 22. The method of any preceding embodiment wherein A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-. 23. The method of any preceding embodiment, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide. 24. The method of any preceding embodiment, wherein the catalyst is employed in an amount of 10 mol% or less, preferably in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate. 25. The method of any preceding embodiment, further comprising a subsequent addition of acid, suitably, a Bronsted acid. 26. The method of embodiment 25, wherein the acid is selected from HCl, HBr, H2SO4, HNO3, CH3COOH, suitably, the acid is an aqueous solution. 27. The method of any preceding embodiment, wherein the base is employed in a dry weight ratio of 2:1 or less per gram of polyethylene terephthalate, suitably, wherein the base is employed in a dry weight ratio of 1.5:1 or less per gram of polyethyelene terephthalate, more preferably wherein the base is employed in a weight ratio of 1:1 or less per gram of polyethylene terephthalate. 28. The method of any preceding embodiment, wherein the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1.29. The method of any preceding embodiment, wherein the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of from 80 to 650 g / L, such as from 100 to 650 g / l, optionally, from 250 to 650 g / L, or in a concentration of from 80 to 250 g / L, preferably in a concentration of 100 to 250 g / L, optionally in a concentration of 150 to 250 g / L . 30. The method of any preceding embodiment wherein the base is present in an amount of 13 molar equivalents or less, optionally, 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate. 31. A method for hydrolysis of poly(ethylene terephthalate) comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyze at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst selected from the following group:, wherein X2is N or P, and each n2is an integer independently selected from 4 to 10, and wherein A2- is an anion. 32. The method of embodiment 31, wherein X2 is N. 33. The method of embodiment 31 or 32, wherein each n2 may independently be 4, 5 or 6. 34. The method of embodiment 31 to 33, wherein A2 is Br or Cl. 35. The method of embodiment 1, wherein the catalyst is selected from:wherein A- is Br- or Cl-. 36. The method of embodiment 1, wherein the catalyst is selected from:wherein A- is Br- or Cl-. 37. The method of any preceding embodiment, wherein the hydrolysis reaction is carried out at a temperature in the range of from 50 to 150°C, optionally, from 60 to 120 °C, such as from 70 to 110°C, for example from 80 to 100°C. 38. The method of any preceding embodiment, wherein the reaction is carried out at a pressure in the range of from 1 atm to 5 atm, preferably, in a range of from 1atm to 2 atm, such as from 1 atm to 1.5 atm, for example at approximately 1 atm. 39. The method of any preceding embodiment, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate; and wherein the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range offrom 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1. 40. .The method of embodiment 39, wherein the catalyst is employed in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate; and wherein the dry weight ratio of base to polyethylene terephthalate is in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1. 41. The method of embodiment 40, wherein the catalyst is employed in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate; and wherein the dry weight ratio of base to polyethylene terephthalate is in a range of from 0.8:1 to 1.2:1. 42. The method of any preceding embodiment, wherein the terephthalic acid formed from the hydrolysis reaction is further processed to form calcium terephthalate, optionally, wherein a metal-organic framework of calcium terephthalate is formed. 43. A compound having the formula:wherein each p is an integer independently selected from 0 to 5, wherein each Rx is independently selected from C1-C12 aliphatic, optionally substituted with one or more selected from the group consisting of C1-C6alkyoxy, C1-C6thioalkyl, Br, Cl, I, and F. 44. The compound of embodiment 43, having the formula:.45. The compound of embodiment 43 or 44, wherein A- is Br-, Cl- or I-. 46. A method for hydrolysing poly (bisphenol A carbonate) comprising: combining poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3 aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms, optionally,14 to 36 carbon atoms, such as from 14 to 30 carbon atoms, further optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms. 47. The method of embodiment 46, wherein each of R1and R2are independently C1-C3alkyl, each of R1and R2are C1alkyl, preferably methyl. 48. The method of embodiment 46 or 47, wherein each of R3and R4is independently selected from C6-C12 alkyl. 49. The method of any one of embodiments 46 to 48, wherein R3and R4are the same. 50. The method of any one of embodiments 46 to 49, wherein R3and R4are C6alkyl, C7alkyl, C8 alkyl, C9 alkyl or C10 alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl nonyl or decyl. 51. The method of any of embodiments 46 to 50, wherein R1and R2are methyl. 52. The method of claim 46, wherein R1and R2are methyl and R3and R4are heptyl, octyl or nonyl. 53. The method of any one of embodiments 46 to 52, wherein A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-.54. The method of any one of embodiments 46 to 53, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide. 55. The method of any one of embodiments 46 to 54, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly (bisphenol A carbonate). 56. The method of any one of embodiments 46 to 55, further comprising a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution. 57. The method of any one of embodiments 46 to 56, wherein the dry weight ratio of base to poly (bisphenol A carbonate) is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1. 58. The method of any one of embodiments 46 to 57, wherein the step of combining poly (bisphenol A carbonate), water, base, and a catalyst, comprises combining poly (bisphenol A carbonate) with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, optionally in a concentration of from 250 to 650 g / L. 59. The method of any one of embodiments 46 to 58, wherein the base is present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of poly (bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly (bisphenol A carbonate). 60. The method of any one of embodiments 46 to 59, wherein the catalyst is selected from:wherein A- is Br- or Cl-.61. A method for hydrolysing poly(ethylene terephthalate) and poly (bisphenol A carbonate) comprising: combining poly(ethylene terephthalate), poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the polyethylene terephthalate and to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms. 62. The method of embodiment 61, wherein the polyethylene terephthalate and poly(bisphenol A carbonate) are mixed or blended together. 63. The method of embodiment 61 or 62, wherein each wherein each of R1and R2are C1alkyl, preferably methyl. 64. The method of any one of embodiments 61 to 63, wherein each of R3and R4is independently selected from C6-C12alkyl. 65. The method of any one of embodiments 61 to 64, wherein R3and R4are the same. 66. The method of any one of embodiments 61 to 65, wherein R3and R4are C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10 alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl nonyl or decyl. 67. The method of any of embodiments 61 to 66, wherein R1and R2are methyl. 68. The method of claim 67, wherein R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.69. The method of any one of embodiments 61 to 68, wherein A- is selected from Cl-, Br-, F-, BF4-, MsO-, TfO-, and CF3C(O)O-, preferably A- is Cl- or Br-. 70. The method of any one of embodiments 61 to 69, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide. 71. The method of any one of embodiments 61 to 70, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate. 72. The method of any one of embodiments 61 to 71, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of poly(bisphenol A carbonate). 73. The method of any one of embodiments 61 to 72, further comprising a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3, CH3COOH, suitably, the acid is an aqueous solution. 74. The method of embodiment 73, wherein the addition of acid involves adjusting pH to selectively protonate salts of bisphenol A, thereby producing bisphenol A, optionally, wherein adjusting pH to selectively protonate salts of bisphenol A involves adjusting pH to pH 7 to pH 8.5, optionally, from a pH of from pH 7.5 to 8. 75. The method of embodiment 73 or 74, wherein the method involves isolation of bisphenol A, prior to isolation of terephthalic acid, optionally, wherein bisphenol A is isolated by filtration. 76. The method of any one of embodiments 73 to 75, wherein addition of acid involves lowering pH to a pH below pH 3 to protonate salts of terephthalic acid. 77. The method of any one of embodiments 61 to 76, wherein the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:1. 78. The method of any one of embodiments 61 to 77, wherein the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in aconcentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, further optionally, from 250 to 650 g / L. The method of any one of embodiments 61 to 78, wherein the base is present in an amount of 13 molar equivalents or less, suitably 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate. The method of any one of embodiments 61 to 79, wherein the base is present in an amount of 13 molar equivalents or less, suitably in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate). The method of any one of embodiments 61 to 80, wherein the catalyst is selected from:wherein A- is Br- or Cl-.

Claims

1. Claims 1. A method for hydrolysing polyethylene terephthalate and / or poly(bisphenol A carbonate) comprising: combining poly(ethylene terephthalate) and / or poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(ethylene terephthalate) and / or poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I) A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic, wherein each of R3and R4is independently selected from C5-C15 aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

2. The method of claim 1, wherein together R1, R2, R3and R4comprise 14 to 36 carbon atoms, suitably, from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

3. The method of claim 1 or 2, wherein each of R1and R2are independently C1-C3 alkyl, optionally, wherein each of R1and R2are independently C1alkyl, preferably methyl.

4. The method of any preceding claim, wherein each of R3and R4is independently selected from C6-C12 alkyl.

5. The method of any preceding claim, wherein R3and R4are C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl or C10alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl, nonyl or decyl.

6. The method of claim 1, wherein R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.

7. The method of any preceding claim, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

8. The method of any preceding claim, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

9. The method of any preceding claim, further comprising a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3, CH3COOH, suitably, the acid is an aqueous solution.

10. The method of any preceding claim, wherein the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:

1.

11. The method of any preceding claim, wherein the dry weight ratio of base to poly(bisphenol A carbonate) is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:

1.

12. The method of any preceding claim, wherein the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, such as 250 to 650 g / L.

13. The method of any preceding claim, wherein the step of combining poly(bisphenol A carbonate), water, base, and a catalyst, comprises combining poly(bisphenol A carbonate) with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, such as from 250 to 650 g / L.

14. The method of any preceding claim wherein the base is present in an amount of 13 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, optionally in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

15. The method of any preceding claim wherein the base is present in an amount of 13 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), optionally, wherein the base is present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), suitably, in anamount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

16. The method of any preceding claim, wherein the catalyst is selected from:

17. A method for hydrolysing polyethylene terephthalate comprising: combining poly(ethylene terephthalate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(ethylene terephthalate), wherein the catalyst is a phase transfer catalyst having a formula selected from:wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3 aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

18. The method of claim 17, wherein together R1, R2, R3and R4comprise 14 to 36 carbon atoms, suitably, from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

19. The method of claim 17 or 18, wherein each of R1and R2are independently C1-C3alkyl, optionally, wherein each of R1and R2are independently C1alkyl, preferably methyl.

20. The method of any one of claims 17 to 19, wherein each of R3and R4is independently selected from C6-C12alkyl.

21. The method of any one of claims 17 to 20, wherein R3and R4are C6alkyl, C7alkyl, C8alkyl, C9 alkyl or C10 alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl, nonyl or decyl.

22. The method of claim 21, wherein R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.

23. The method of any one of claims 17 to 22, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

24. The method of any one of claims 17 to 23, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

25. The method of any one of claims 17 to 24, further comprising a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3, CH3COOH, suitably, the acid is an aqueous solution.

26. The method of any one of claims 17 to 25, wherein the dry weight ratio of base to polyethylene terephthalate is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:

1.

27. The method of any one of claims 17 to 26, wherein the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, such as 250 to 650 g / L.

28. The method of any one of claims 17 to 27 wherein the base is present in an amount of 13 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, optionally in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate, suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of polyethylene terephthalate.

29. The method of any one of claims 17 to 28, wherein the catalyst is selected from:wherein A- is Br- or Cl-.

30. A method for hydrolysing poly(bisphenol A carbonate) comprising: combining poly(bisphenol A carbonate), water, base, and a catalyst, and heating for a time sufficient to hydrolyse at least in part the poly(bisphenol A carbonate), wherein the catalyst is a phase transfer catalyst having a formula selected from: Formula (I)wherein X1 is N or P, wherein A1- is an anion, wherein each of R1and R2is independently selected from C1-C3aliphatic, wherein each of R3and R4is independently selected from C5-C15aliphatic, wherein together R1, R2, R3and R4comprise at least 14 carbon atoms.

31. The method of claim 30, wherein together R1, R2, R3and R4comprise 14 to 36 carbon atoms, suitably, from 14 to 30 carbon atoms, optionally, 16 to 24 carbon atoms, such as from 16 to 22 carbon atoms.

32. The method of claim 30 or 31, wherein each of R1and R2are independently C1-C3 alkyl, optionally, wherein each of R1and R2are independently C1 alkyl, preferably methyl.

33. The method of any one of claims 30 to 32, wherein each of R3and R4is independently selected from C6-C12alkyl.

34. The method of any one of claims 30 to 33, wherein R3and R4are C6 alkyl, C7 alkyl, C8 alkyl, C9alkyl or C10alkyl, optionally, wherein R3and R4are selected from hexyl, heptyl, octyl, nonyl or decyl.

35. The method of claim 30, wherein R1and R2are methyl and R3and R4are heptyl, octyl or nonyl.

36. The method of any one of claims 30 to 35, wherein the base is an alkali metal hydroxide or an alkaline earth metal hydroxide, suitably, wherein the base is selected from sodium hydroxide, potassium hydroxide, caesium hydroxide and magnesium hydroxide.

37. The method of any one of claims 30 to 36, wherein the catalyst is employed in an amount of 5 mol% or less, suitably, in an amount of 2.5 mol% or less, more suitably, in an amount of 1.5 mol% or less relative, most suitably in an amount of 1 mol% or less per mole of monomeric repeating unit of polyethylene terephthalate.

38. The method of any one of claims 30 to 37, further comprising a subsequent addition of acid, suitably, a Bronsted acid, optionally, wherein the acid is selected from HCl, HBr, H2SO4, HNO3,CH3COOH, suitably, the acid is an aqueous solution.

39. The method of any one of claims 30 to 38, wherein the dry weight ratio of base to poly(bisphenol A carbonate) is in the range of from 0.5:1 to 2:1, preferably, in a range of from 0.7:1 to 1.3:1, such as from 0.8:1 to 1.2:1, for example from 0.9:1 to 1.1:1, optionally, in a weight ratio of 1:

1.

40. The method of any one of claims 30 to 39, wherein the step of combining poly(ethylene terephthalate), water, base, and a catalyst, comprises combining polyethylene terephthalate with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, such as 250 to 650 g / L.

41. The method of any one of claims 30 to 40, wherein the step of combining poly(bisphenol A carbonate), water, base, and a catalyst, comprises combining poly(bisphenol A carbonate) with water in a concentration of 80 to 650 g / L, preferably in a concentration of 100 to 550 g / L, optionally in a concentration of 250 to 500 g / L, such as from 250 to 650 g / L.

42. The method of any one of claims 30 to 41, wherein the base is present in an amount of 13 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), optionally, wherein the base is present in an amount of 10 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate), suitably, in an amount of 5 molar equivalents or less relative to the number of moles of monomer unit of poly(bisphenol A carbonate).

43. The method of any one of claims 30 to 42, wherein the catalyst is selected from:FRKelly

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