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The rate of hydrolysis of insecticidal 1-(6-chloro-3-pyridylmethyl)-2-nitro-iminoimidazolidine (common name; imidacloprid) have been investigated in 15%(v/v) aqueous dioxane at 45℃. From the kinetics and non-kinetics data such as pH-effect, solvent effect(m=0.04, n=0.30 & m≪ℓ), thermodynamic parameter(△H^*=16.14㎉·㏖^(-1) & △S^*=-0.03e.u.), rate equation (k_(obs.)=4.56×10^(-3)[OH^-]) and analysis of hydrolysis product, 1-(6-chloro-3-pyridylmethyl-2)-imidazolidinon, the hydrolysis mechanism of imidacloprid is proposed that the specific base catalyzed hydrolysis(k_(OH)) through nucleophilic addition-elimination (Ad_N-E) mechanism proceed via intermediate, 1-(6-chloro-3-pyridylmethyl)-2-hydroxy-2-imidazolidinylisonitraminate (Ⅰ) and β-3-(6-chloro-3-pyridylmethyl)aminoethyl-1-nitrourea(Ⅲ). And the half-life(t½) of hydrolytic degradation at pH 8.0 and 45℃ was about 4.5 months.
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