Nitration Reaction of Butyl p-Hydroxybenzoate by Photodecornposition of Sodium Nitrite Aqueous Solution

Abstract

The photochemical reaction of butyl p-hydroxybenzoate (BHB) initiated by irradiation of Hg 3650 A in sodium nitrite aqueous solution was studied. Butyl 3-nitro-4-hydroxybenzoate (BNH) was produced as a main product of photochemical nitration reaction. The quantum yield of the formation of BNH, OBNH was 0.012 under conditions of 8 mmol/l BHB, 0.115 moll NaNO₂, and pH 9.7. The reaction was enhanced in a NO, -bubbled solution but hindered by the addition of sodium thiocyanate and sodium bromide which were used as OH radical scavengers (Table 2). Thus, it is suggested that both of H radical and NO₂ are involved in the nitration reaction. by photodecomposition of nitrite ions in aerated aqueous solution. The reaction mechanism is proposed based on the addition of H to the aromatic ring of BHB and the successive reaction of NO₂. The electron abstruction from NO₂ by the OH-adduct may result in the nitration.