Molecular and dissociative adsorption of 2-bromo-1-chloropropane on Cu(111)

The molecular adsorption and subsequent reaction of 2-bromo-1-chloropropane with Cu(111) has been studied using primarily ultraviolet photoelectron spectroscopy and line of sight temperature programmed desorption. The molecule reacts by the following two steps:ClCH2CHBrCH3(g)→ClCH2CHBrCH3(phys)ClCH2CHBrCH3(phys)→Cl(chem)+Br(chem)+CH2CHCH3(g)↑At room temperature these reactions go to completion with emission of propene and formation of a (3×3)R30°-Cl/Br surface. At 100 K adsorption of the first layer of BCP occurs molecularly, but with the adsorption of a second and subsequent layers, the activation energy for decomposition of the first layer is lowered, such that it decomposes at 100 K. On heating a multilayer surface of BCP formed at 100 K, the second and third layers of BCP are also observed to decompose with emission of propene and formation of the same (3×3)R30°-Cl/Br surface formed by room temperature adsorption. It was found that a single layer of BCP is stabilised by adsorption to this halogenated surface, only desorbing at the relatively high temperature of 180 K.