## Abstract

The photolysis of mercury diethyl vapour has been investigated in a static system over a pressure range of 0 to 80 mm. and a temperature range of 75 to 200 degrees C. The products were analyzed for C$_{2}$H$_{6}$, C$_{2}$H$_{4}$, C$_{4}$H$_{10}$, C$_{4}$H$_{8}$. No significant amounts of H$_{2}$, CH$_{4}$, C$_{4}$H$_{8}$ or higher hydrocarbons were found. Rotating sector experiments have enabled a complete determination of the velocity constants of the reactions: $ \matrix\format\l \\ (1)\ \text{C}_{2}\text{H}_{5}+\text{C}_{2}\text{H}_{5}=\text{C}_{2}\text{H}_{4}+\text{C}_{2}\text{H}_{6}, \\ (2)\ \text{C}_{2}\text{H}_{5}+\text{C}_{2}\text{H}_{5}=\text{C}_{4}\text{H}_{10}, \\ (3)\ \text{C}_{2}\text{H}_{5}+\text{Hg}Et_{2}=\text{C}_{2}\text{H}_{4}+\text{C}_{2}\text{H}_{6}+\text{Hg}+\text{C}_{2}\text{H}_{5}. \endmatrix $ Energies of activation and frequency factors for these reactions have been deduced. E$_{1}$-E$_{2}$ = 0$\cdot $8 $\pm $ 0$\cdot $2 kcal./mole, E$_{2}\not>$ 0$\cdot $65 kcal./mole has been deduced from k$_{2}$ at 150 degrees C and the calculated collision frequency.