Effects of 2,4-ionenes of different molar masses on the oxidative coupling of thiol catalyzed by cobaltphthalocyanine

Almtraet--A photometric method is developed for the determination f the molar mass of 2,4-ionene by attaching a chromophoric moiety to its end-groups. Molar mass determination f these polyelectrolytes by acid-base titration of the amine end-groups i also possible, and confirms the photometric method. The effects of molar mass of 2,4-ionenes on the oxidative coupling of 2-mercaptoethanol (ME) was studied in the presence of cobalt(II)phthalocyanine-tetra-sodium-sulphonate (CoTSPc). Monomeric analogues of 2,4-ionene showed no increase of reaction rate as compared with the polymer-free system. However, relatively low molar mass ionene (M, = 1740) showed a dramatic increase of reaction rate. The reactivity showed an optimum around pH = 8. Saturation kinetics (Michaelis-Menten kinetics) were observed. The calculated turnover number was 3200 sec- t and3600sec 1for)kl"n = 6600and h,St, = 1740, respectively. The stoichiometry of the reaction was disturbed at low thiol concentration

Cationic latices as cocatalyst in the cobaltphthalocyanine-catalyzed oxidation of 2-mercaptoethanol

3-Methacrylamidopropyltrimethylammonium chloride (I) homopolymer and I-styrene copolymer were tested as cocatalysts in the autoxidn. of 2-mercaptoethanol to 2,2'-dithiodiethanol in the presence of tetra-Na Co(II) phthalocyaninetetrasulfonate (II). Both polymer systems enhanced the catalytic activity compared with the polymer-free II-contg. system. The systems invariably showed an enzyme-like behavior. However, the stability after successive runs was not quite satisfactory. The obsd. catalytic activities and spectrophotometric measurements indicated that, in addn. to a high surface charge d., flexible polymeric cationic chains of sufficient length were also necessary to enhance the activity of II-bound latex systems in thiol oxid