Study of the pesticide naptalam degradation; theoretical and experimental

Abstract

Two different processes for degradation of N-1-naphthylphthalamic acid (naptalam, Nap) are known. Formation of 1-naphthylamine (Na) and phthalic acid (Pha) is one of the degradation processes. Another degradation product of Nap is N-(1-naphthyl) phthalimide (Nad). The HPLC results show that the production of Na and Pha is a major degradation reaction of Nap. The ab initio study, in Hartree-Fock level and three standard basis sets, emphasise these results and show that these degradation processes have lower Gibbs energy. The Fourier-transform infrared (FT-IR) studies show that continuously heating Nap, in solid and solution conditions, produce only Nad. These phenomena can be related to lower barrier formation energy of Nad than Na.