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Fig. 2. Kinetics of the esterification of acetic acid with methanol. The catalyst concentration: 0.2 wt % The model:concentration-based rate equations with temperature-dependent parameters.

MECHANISM AND KINETICS Two overall reactions are considered in the kinetic model: esterification of acetic acid withmethanol and esterification of hydrogen iodide to methyl iodide. The overall reactions can be written as follows: O CH3COOH + CH3OH ~H3OL CH3C~ + H20 OCH 3 (1) (2)

commenced with some water present inthe beginning in the liquid phase). The protolysis equilibria are (aI) HI + H20~,~-I- + H 3 0 + (3)

(aII) C H 3 C O O H + HzO~.-~-CH3COO- + H3 O+ (4) The equilibria are both rapid, but the acidstrengths of C H 3 C O O H and HI are very different: C H 3 C O O H is a rather weak acid (pKcn3coon = 4.75 in aq. at 25°C, Weast e t a l . , 1986), whereas HI is a very strong acid (pKm < - 7 in aq. at...