Heterogeneous catalysis in solution. Part V. Catalysis by charcoal and silver iodide of the ethyl iodide–silver nitrate reaction
The kinetics of the ethyl iodide–silver nitrate reaction in 0·02M-aqueous potassium nitrate solution at 5° were studied in the presence of charcoal and of silver iodide. The rates depended on the concentration of each substrate either raised to a fractional power, as in a Freundlich adsorption isotherm, or arranged in a form analogous to a Langmuir isotherm, and thus indicated a Langmuir–Hinshelwood mechanism. When the difference in surface areas was taken into account, silver iodide was found to be a more effective catalyst than charcoal by a factor of at least 40. The activation energies were 20 kcal. for the homogeneous reaction, 10.4 kcal. for the charcoal-catalysed process, and 8.5 kcal. for the reaction on the silver iodide surface.