Immobilization of 2,4‐ionene on a macroporous poly(styrene‐divinylbenzene) resin and its effect on the rate of the cobaltphthalocyanine‐catalyzed oxidative coupling of mercaptoethanol

Abstract

AbstractA poly(quaternary ammonium) salt, 2,4‐ionene, has been immobilized on a macroporous chloromethylated poly(styrene‐divinylbenzene) resin (XAD‐2). The ionene content of the resin, determined by CHN elemental analysis, was 50.2 g/kg resin. The most important side effect of the modified resin, catalyst (2,4‐ionene) bleeding, can be detected by a spectrophotometric method capable of determining extremely low concentrations of free ionene in the supernatant of the resin.The activity of these immobilized 2,4‐ionene/cobalt(II)phthalocyanine‐tetrasodiumsulfonate (CoTSPc) complexes towards the oxidative coupling of thiols is much lower than in the homogeneous case, but still considerably higher than for the polymer free system. The observed decrease in reaction rate does not originate from the considerable mass transfer resistances but predominantly from catalyst properties like a very low local N+/Co ratio. The active sites appear to be present in the outer shell of the resin particles only.