Highly effective and fast oxidation of naphthalene(s) to phthalic acid(s) under biphasic conditions using nominal catalyst loading (0.5 mol%) of ruthenium chloride, 2.5 mol% tetrabutyl ammonium bromide as phase transfer catalyst and inexpensive aqueous sodium hypochlorite (NaOCl) as reagent has developed. Recovery, regeneration and reuse of the catalytic system add its merit to green chemistry. A nominal loading (0.5 mol%) of ruthenium chloride as catalyst and inexpensive aqueous sodium hypochlorite (aq. NaOCl) as reagent are found to be highly effective reaction system for the partial oxidation of naphthalene(s) to phthalic acid(s) under phase transfer catalyst (PTC) conditions. Recovery, regeneration and reuse of the "ruthenium-PTC" catalytic system add its merit to green chemistry.