Preparation of 2-methyl-l,4-naphthoquinone (vitamin K_3) by catalytic oxidation of 2-methyl-1-naphthol in the presence of iron phthalocyanine supported catalyst

摘要

Iron tetrasulfophthalocyanine (FePcS) supported catalyst was prepared by covalent grafting onto amino-modified silica by a novel practical one-pot method using activation of sulfonate groups of FePcS by triphenylphosphine triflate.FePcS-SiO_2 in combination with ~tBuOOH behaved as an efficient catalyst for the oxidation of 2-methyl-l-naphthol to 2-methyl-l,4-naphthoquinone,vitamin K_3.To optimise the catalytic system,the influence of different reaction parameters on the efficiency of this oxidation has been studied.Vitamin K_3 was obtained with 59% selectivity at 96% conversion of 2-methyl-l-naphthol using only 0.5 mol% of catalyst.~(18)O labelling experiments indicate a non-radical mechanism for this oxidation.