Autooxidation of alkyl mercaptans catalysed by cobalt(II)phthalocyanine tetrasodium sulphonate in reverse micelles

Sulfonated Co(II) phthalocyanines covalently anchored at organic polymers as catalyst for mild oxidation of mercaptans

Current work is devoted to covalent immobilization of sulfonated derivatives of cobalt phthalocyanines “Merox catalysts” on the surfaces of polypropylene and polyethylene terephthalate. Their catalytic activity in reaction of mild oxidation of sulfur compounds to disulfides with oxygen of the air was studied. Anchoring of the catalyst on this polymer prevents its leaching and promotes its efficient recovering and recycling without significant loss of catalytic activity.

Catalytic Properties of Cobalt Phthalocyanines Chemically Bonded to Polymer Anchored onto Silochrome Surface

Catalytic systems consisting of cobalt phthalocyanine grafted to maleic anhydride-styrene copolymer chemically linked with γ-aminopropylated silochrome have been prepared. In the process of sulfide oxidation with air oxygen the specific catalytic activity of these systems depends strongly on the phthalocyanine concentration in the catalyst. At low phthalocyanine concentrations (below 0.4 × 10−6 mol g−1) the catalytic activity is more than an order of magnitude larger than that of homogeneous catalysts and cobalt phthalocyanine adsorbed on a silochrome surface. The different ways of preparing the catalysts are reflected in the kinetic characteristics of the oxidation process.

Facile, green encapsulation of cobalt tetrasulfophthalocyanine monomers in mesoporous silicas for the degradative hydrogen peroxide oxidation of azo dyes

A facile and green approach that improves the catalytic lifetime of cobalt tetrasulfophthalocyanine (CoTSPc) for the degradation of dyes is presented. Structurally ordered mesoporous silicas (MCM-41, MCM-48 and SBA-15), microporous aluminosilicates (ZSM-5) and macroporous alumina (γ-Al(2)O(3)) with different pore sizes were selected for the immobilization of CoTSPc, and a wide range of pH conditions (pH values from 4 to 12) were tested with the CoTSPc immobilization procedure. In the catalytic oxidation study, CoTSPc that was immobilized to MCM-41 silica (CoTSPc@MCM-41) prepared at a pH of 12 showed the longest catalytic lifetime. The TOC removal and discoloration of C. I. Acid Red 73 was approximately 60% and 82%, respectively, in the presence of CoTSPc@MCM-41 with H(2)O(2) after 3h. These results indicate that MCM-41, which has a matching size between its mesopores (30 Å) and CoTSPc molecules (25 Å), can prevent CoTSPc molecules from aggregating and improve its catalytic lifetime. In addition, the ability of CoTSPc@MCM-41 to degrade other dyes, and the reuse studies, demonstrated that CoTSPc@MCM-41 could be reused for the degradation of most common dyes.

Biomimetic oxidation of ibuprofen with hydrogen peroxide catalysed by horseradish peroxidase (HRP) and 5,10,15,20-tetrakis-(2',6'-dichloro-3'-sulphonatophenyl)porphyrinatoiro n(III) and manganese(III) hydrates in AOT reverse micelles

The oxidation of ibuprofen with H2O2 catalysed by Horseradish peroxidase (HRP), Cl8TPPS4Fe(III)(OH2)2 and Cl8TPPS4Mn(III)(OH2)2 in AOT reverse micelles gives 2-(4'-isobutyl-phenyl)ethanol (5) and p-isobutyl acetophenone (6) in moderate yields. The reaction of ibuprofen (2) with H2O2 catalysed by HRP form carbon radicals by the oxidative decarboxylation, which on reaction with molecular oxygen to form hydroperoxy intermediate, responsible for the formation of the products 5 and 6. The yields of different oxidation products depend on the pH, the water to surfactant ratio (Wo), concentration of Cl8TPPS4Fe(III)(OH2)2 and Cl8TPPS4Mn(III)(OH2)2 and amount of molecular oxygen present in AOT reverse micelles. The formation of 2-(4'-isobutyl phenyl)ethanol (5) may be explained by the hydrogen abstraction from ibuprofen by high valent oxo-manganese(IV) radical cation, followed by decarboxylation and subsequent recombination of either free hydroxy radical or hydroxy iron(III)/manganese(III) porphyrins. The over-oxidation of 5 with high valent oxo-manganese, Mn(IV)radical cation intermediate form 6 in AOT reverse micelles by abstraction and recombination mechanism.