Microwave irradiated synthesis and characterization of 1, 4-phenylene bis-oxazoline form bis-(2-hydroxyethyl) terephthalamide obtained by depolymerization of poly (ethylene terephthalate) (PET) bottle wastes

The aminolytic depolymerization of PET bottle waste with ethanolamine by conventional heating and microwave irradiation heating method was attempted with heterogeneous, recyclable acid catalysts such as beta zeolite (SiO2/ AlO2= 15 Na- form) and montmorillonite KSF. The pure product bis-(2-hydroxyethyl) terephthalamide (BHETA) of aminolysis was obtained in good yield (85- 88%). The BHETA, thus obtained, was subjected to cyclization reaction by heating with polyphosphoric acid as well as by chlorination (using phosphoryl chloride), bromination (using red phosphorous and liquid bromine) and nitration (conc. HNO3 + conc. H2SO4) followed by conventional and microwave irradiation heating in N,N- dimethyl formamide/ potassium carbonate solution. The product so obtained was 2, 2’-(1,4-phenylene)–bis-(2-oxazoline) (PBO), which has applications in polymer synthesis as a chain extender/ chain coupling agent or a cross linker. The productswere analyzed by FTIR, DSC, Mass and NMR (1H and 13C NMR).