Poly(alkylene Phosphates): Synthetic Strategies

摘要: Poly(alkylene phosphate)s are an interesting class of polymers because both the polymer chain and substituents can be readily varied. Several synthetic methods available for preparation these polymers. The most versatile involve poly(alkylene phosphonate) s as intermediates. Two promising phosphonate)s ring opening polymerizations cyclic phosphonates condensation dimethyl phosphite dialcohols. catalyzed by triisobutylaluminum very sentitive to nature alkylene group. With R = −(CH2)3−, polymerization gives a monomer: mole ratio 1:1. separated from monomer using fractional precipitation, only slowly reeuilibrates form monomer. In contrast, with −(CH2)2− occurs without catalyst give 1:9. is low molecular weight cannot crystallization due rapid reequilibration. −(CH2CH(CH2OMe))−, no in absence catalyst, Attempts purify gave poor yields polymer. Reaction or −(CH2CH(CH2OMe))− monomer-polymer mixtures chlorine then either imidazole methanol excess diethylamine that monomeric impurities precipitation. triethylene glycol 1,12-dodecanediol have been carried out followed 1H, 13C 31P NMR spectroscopy. These studies indicate that, under reaction conditions used polymerizations, at much lower temperatures than reported literature, first step appears displacement one methoxy groups diol. generate higher heating mixture 180 – 200 °C long periods time caused decomposition