Remarkable solvent effect on the yield and specificity of oxidation of naphthalene catalyzed by iron (III)porphyrins

Oxidation of naphthalene was performed with tetrakis(pentaflourophenyl)porphyrin iron(III)chloride ((F20TPPFeCl)-Cl-III), or tetrakis(2,6-dichlorophenyl)porphyrin iron(III)chloride ((TDCPPFeCl)-Cl-III), or tetramesitylporphyrin iron(III)chloride ((TMPFeCl)-Cl-III) as catalyst and metachloroperbenzoic acid or pentafluoroiodosylbenzene or tert-burythydroperoxide as oxidant in different media in the presence of imidazole as cocatalyst. In aprotic solvent (CH3CN:CH2Cl2, 1:1) and in the presence of (F20TPPFeCl)-Cl-III, 1-naphthol, 2-naphthol and 1,4-naphthoquinone yields based on metachloroperbenzoic acid oxidant were 77.7, 2.1 and 5.6%, respectively. The best yield for 1,4-naphthoquinone in methanol with (F20TPPFeCl)-Cl-III was 52.8%. The effect of bases on the yield and specificity of the naphthalene oxidation were studied. When imidazole changed to pyridine in (F20TPPFeCl)-Cl-III, the yield of 1-naphthol decreased from 77.7 to 55.3%, whereas for (TDCPPFeCl)-Cl-III catalyst, the yield changed from 61.1 to 18.3%. (C) 2002 Elsevier Science BV All rights reserved.