Resumo

CAMPANELLA, A.  e  BALTANAS, M. A.. Degradation of the oxirane ring of epoxidized vegetable oils in liquid-liquid systems: I. Hydrolysis and attack by H₂O₂. Lat. Am. appl. res. [online]. 2005, vol.35, n.3, pp.205-210. ISSN 0327-0793.

This work analyzes the impact of the main process variables (agitation, pH, temperature, volumetric ratio and concentration levels) on the degradation of the oxirane ring of epoxidized vegetable oils (VO) by hydrolysis and hydrogen peroxide in two-phase (polar-organic) systems, when a homogeneous acid catalyst is used. Acid hydrolysis of epoxidized VO is a very slow reaction that proceeds at the liquid-liquid interphase, but only after an extended 'induction period' of several hours, during which enough active interfacial area is developed. The process is transport-controlled, as the influence of temperature was found to be almost negligible (Ea= 349.2 ± 10.15 cal mol^-1). On the contrary, the degradation of the oxirane ring with aqueous H₂O₂ in acid media is fast and proceeds under a kinetic regime (Ea = 16.3 ± 0.72 kcal mol^-1), without any observable induction times. If the concentration of H₂O₂ is kept within moderate values the reaction order with respect to this reactant is two, the expected value.

Palavras-chave : Epoxidized Vegetable Oil; Oxiranes; Hydrolysis; Hydrogen Peroxide.

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