Effects of pH and organic co-solvents on the oxidation of naphthalene with peroxosulfate catalyzed by iron(III) tetrakis(p-sulfonatophenyl)porphyrin

Abstract

The oxidation of naphthalene was investigated in a biomimetic catalytic system using KHSO 5 and iron(III) tetrakis(p-sulfonatophenyl)porphyrin ( FeTPPS ) in order to elucidate the influence of solution forms, such as buffer pH and co-solvent types, on the reaction. 1,4-naphthoquinone was the main byproduct and the efficiency of oxidation, particularly 1,4-naphthoquinone formation, was influenced by pH and the type of co-solvent used. The most efficient conversion of 1,4-naphthoquinone was observed at an acidic pH (= 3). At higher pH , the formation of μ-oxo species ( OFe 2( TPPS )2) leads to a decrease of the percentage of naphthalene oxidized. In addition, the organic co-solvents (methanol, ethanol, 2-propanol and acetonitrile) influenced the amounts of naphthalene conversion. The amounts of 1,4-naphthoquinone formed were related to the electron donating character of the organic co-solvents.

Complex formation of water-soluble iron(III)-porphyrin with humic acids and their effects on the catalytic oxidation of pentachlorophenol

“…In our experimental conditions (5 M Fe(III)-TPPS, pH 6), the wavelength corresponding to the absorption maximum for Fe(III)-TPPS (394 nm) was similar to that at pH 2, where aggregation could not occur. However, at pH 7 the wavelength shifted to 406 nm, indicating the formation of O-(Fe(III)-TPPS) 2 species [27]. These results show that aggregation does not cause the loss of catalytic activity under our experimental conditions.…”

“…Fe(III)-TPPS (Na 3 C 44 H 25 N 4 O 12 S 4 Fe·2H 2 O, FW 1090.79) was prepared according to the method of Kawasaki et al [27], and KHSO 5 was purchased from Merck. PCP (99.0% purity) was purchased from Aldrich, and a stock solution (0.01 M) was prepared by dissolving it in acetonitrile.…”

“…It has been reported that the aggregation of Fe(III)-TPPS can yield -oxo species, O-(Fe(III)-TPPS) 2 , which are produced in higher concentration of Fe(III)-TPPS and at a higher pH [27]. In our experimental conditions (5 M Fe(III)-TPPS, pH 6), the wavelength corresponding to the absorption maximum for Fe(III)-TPPS (394 nm) was similar to that at pH 2, where aggregation could not occur.…”

Catalytic oxidation of tetrabromobisphenol A by iron(III)-tetrakis(p-sulfonatephenyl)porphyrin catalyst supported on cyclodextrin polymers with potassium monopersulfate

“…TBBPA (>98% purity) was purchased from Tokyo Chemical Industry (Tokyo, Japan). FeTPPS was synthesized by refluxing 5,10,15,20-tetrakis(4-sulfonatephenyl)-21H,23H-porphyrin (Dojindo Laboratory, Kumamoto, Japan) and FeSO 4 ·7H 2 O in ultra-pure water [39]. The ␣-, ␤-and ␥-CDPs were purchased from Wako Pure Chemicals (Osaka, Japan).…”

Degradation of pentachlorophenol in contaminated soil suspensions by potassium monopersulfate catalyzed oxidation by a supramolecular complex between tetra(p-sulfophenyl)porphineiron(III) and hydroxypropyl-β-cyclodextrin

“…Tetra(p-sulfophenyl)porphineiron(III) (Fe(III)-TPPS) was prepared according to a method described in a previous report [22]. KHSO 5 was obtained as a triple salt, 2KHSO 5 ·KHSO 4 ·K 2 SO 4 (Merck).…”