posted on 2023-03-30, 14:36authored byIngeborg-Helene Svenum, Sylvain Gouttebroze, Francesca L. Bleken
In the Müller–Rochow process, where CH3Cl reacts with silicon to form methylchlorosilanes, copper
is used
as a catalyst. To provide insight into mechanisms leading to coke
formation in the process, the interactions and decomposition of CH3Cl with four different surface orientations of copper were
investigated by means of density functional theory. CH3Cl adsorbs weakly on the different surfaces, and decomposition occurs
preferentially by splitting the C–Cl bond, leaving CH3 and Cl on the surface. Dehydrogenation of CH3 can be
considered as a key step toward coke formation as the presence of
CH2 can lead to C–C bond coupling or further dehydrogenation.
All surfaces investigated, Cu(100), Cu(111), Cu(410) and Cu(221),
show that CH2 formation is thermodynamically favorable
relative to gaseous CH3Cl, and the path with lowest energy
barriers is found for the Cu(410) surface.