Synthesis of 1,2-bis(2-oxazolinyl-2)ethane and its application as chain extender for poly(ethylene terephthalate)

Summary The reaction of ethanolamine (EA) with nitriles is a general route to prepare oxazolines. However, in case of vicinal nitrile groups, cyclic imidines are formed. It is shown, that succinonitrile gives with EA mainly 1-(hydroxyethyl)-2,5-bis-(hydroxyethylimine) azacyclopentane (= triol). The corresponding 1,2 bis-(2-oxazolinyl-2) ethane (BOXE) is formed by heating the triol. BOXE can be used as chain extender of poly(ethylene terephthalate) (PET). If PET is heated with BOXE at 270 °C the viscosity increases first. However, on prolonged heating the viscosity decreases again, which can not be ascribed to the normal degradation processes. Therefore, a mechanism is proposed in which the chain scission takes place in the newly formed bridge.