Synthesis, polymerization, and copolymerization of diphenyl‐p‐styrylphosphine, phosphine oxide, and phosphine sulfide

Abstract

Listen

Translate article

AbstractDiphenyl‐p‐styrylphosphine (I), prepared by the reaction of diphenylchlorophosphine with p‐styrylmagnesium chloride, was converted to the corresponding oxide (II) and sulfide (III) by treatment with tert‐butyl hydroperoxide and sulfur, respectively. These substituted styrenes polymerize readily with thermal or free radical initiation to high molecular weight polymers. These polymers are somewhat more thermally stable than polystyrene. Thus their Ti's in air were in the range 320–365°C. and in nitrogen, 375–395°C. Their T10's were in the 390–415°C. range in air and 425–435°C. in nitrogen. Polystyrene in air has a Ti of 263°C. and a T10 of 340°C. The monomers copolymerize readily with styrene and methyl methacrylate, the low conversion polymers always containing more phosphorus than the monomer mixtures. Reactivity ratios were determined, from which Q and e values were calculated. These values for the following monomer pairs are (phosphorus monomer M2): styrene‐I, r1 0.52, r2 1.43, Q2 1.34, e2 −0.30; styrene‐II, r1 0.42, r2 1.40, Q2 1.34, e2 −0.07; styrene‐III, r1 0.43, r2 1.49, Q2 1.37, e2 −0.13; MMA‐I, r1 0.32, r2 0.91, Q2 1.58, e2 0.80; MMA‐II, r1 0.38, r2 1.46, Q2 1.42, e2 −0.35; MMA‐III, r1 0.29, r2 1.22, Q2 1.58, e2 −0.62. Analysis of these data indicates that these phosphorus moieties are activating through strong electronegative effects. The extent of activation is intermediate in intensity between mildly activating groups (e.g. Cl) and strongly activating groups (e.g. CN or NO2). The behavior of diphenyl‐p‐styrylphosphine is of particular interest in this respect, since its electronegativity points to strong electron delocalization.