KINETIC MODELING OF N-HEXANE OXYFUNCTIONALIZATION BY HYDROGEN-PEROXIDE ON TITANIUM SILICALITES OF MEL STRUCTURE (TS-2)

Catalytic oxyfunctionalization of n-hexane by aqueous H2O2 is a comple x multiphase reaction. The kinetic modeling of a set of catalytic reac tion experiments performed in a batch reactor in the presence of vario us solvents was achieved. In the present report, a two-phase kinetic m odel describing the influence of these cosolvents (methanol, acetone, and water) on the initial rates as well as rates at varying catalytic reaction times, observed in the presence of titanium silicalites of ME L structure (TS-2), was proposed. The solubility of n-hexane in the aq ueous phase was estimated using liquid-liquid equilibrium concentratio ns calculated by the standard UNIQUAC model. The model is based on a s imple description of the selective oxidation reaction mechanism of n-h exane on TS-2. The kinetic, derived assuming pseudo-steady-state condi tions and no mass transfer limitations, showed second-order reaction r ates with respect to H2O2 concentration in the aqueous phase. The comp lete absence of activation of the primary carbon was also discussed. ( C) 1996 Academic Press, Inc.