1984 Volume 27 Issue 6 Pages 463-471
The hydrogen in the gas phase and in the paraffin hydrocarbons become reversible at above 300°C when metal supported active carbon is incorporated in the system. The metal-active carbon promotes the transfer of hydrogen atom by normal and reverse spillover effects. Any material on active carbon which can dissociate molecular hydrogen to atomic hydrogen can be the gate of hydrogen spillover. In the case of catalytic dehydrogenation, paraffins are dehydrogenated by active carbon to form olefins or aromatics and surface hydrogen. The hydrogen atoms on the carbon migrate on its surface untill they are transfered onto the metal particles where they combine to form hydrogen molecules which are desorbed into the gas phase. The metal particles on the carbon merely accelerate the desorption of hydrogen. The organo-sulfur compounds incorporated in a paraffin dehydrogenation system react with the hydrogen atoms on the metals to form hydrocarbons and hydrogen sulfide by hydrogenolysis. The hydrogen on the metal can be the hydrogen found in the gas phase and in the paraffin molecules. By regulating the hydrogen pressure (initial pressure 6atm) and temperature (390°C), the hydrogenolysis of thiophene by decaline with a Mo-active carbon catalyst proceeds without any consumption of gaseous hydrogen.
