Some observations on complexes of a cobalt phthalocyanine with poly(vinylamine) and their catalytic activity in the autoxidation of thiols

Abstract

Complexes of the tetrasodium salt of cobalt(I1)-tetrasulfophthalocyanine and poly(viny1amine) were applied as bifunctional catalysts for the autoxidation of thiols to disulfides. Optical and catalytic experiments gave supporting evidence to the hypothesis, that the isolation of cobalt centers and the catalytic activity can be promoted by increasing the relative amount of polymeric base. It appeared that the specific catalytic activity of the polymeric catalysts depends on the number average degree of polymerization (F,) of the applied polymer samples. In particular at relatively high cobalt content, samples with comparatively low Fn give more protection against aggregation of cobalt sites (i.e. inactivation) and, therefore, effect a higher specific catalytic activity. A statistical calculation, suitable to determine the distribution of cobalt sites over the polymeric coils, supports the interpretation of the experimental data.

Catalytic activity of cationic latices prepared according to the shot-growth method

“…The coupling can be described by a Table 3 respectively. Consideration to the occurrence of maxima in these curves is given elsewhere [19,20]. The dependence of reaction rate on thioi concentration at optimum pH and [N +] conditions is depicted in Fig.…”

Effects of complexation of oppositely charged water-soluble cobaltphthalocyanines on the catalytic mercaptoethanol autoxidation

“…Other arguments supporting the mechanism of break-up of CoPc ( NaS0,)4 dimers after ligation can be based on earlier described experiments for a CoPc (NaSO,), system with poly(viny1 amine) (PVAm) as polymeric promoter [37,38]. UV-VIS spectroscopy showed that the amount of dimers decreased upon raising the PVAm concentration, while enhanced catalytic activities were found.…”

Preparation, characterization, and catalytic activity of synthetic carbon-supported (phthalocyaninato)cobalt-containing complexes in dodecane-1-thiol oxidation reaction

“…The ideal bifunctional heterogeneous catalyst for the Merox process should combine a catalytically active transition-metal center with a high dioxygenase activity and basic groups on the surface of the catalyst [4,25]. In order to satisfy both of these conditions, several approaches have been suggested in the literature including the physical adsorption of cobalt phthalocyanine on the surface of a basic inorganic support or covalently linking the phthalocyanines to the surface of aminosilica gel or aminated organic polymers [25,26].…”