Reactions of Molten LiI with I2, H2O, and O2 Relevant to Halogen Mediated Oxidative Dehydrogenation of Alkanes

Constant-temperature ab initio molecular dynamics is used to study reactions between molten LiI and gas phase molecules (O-2, H2O, and 12) in an attempt to elucidate some aspects of the alkane oxidative dehydrogenation activity performed in the presence of molten LiI. We investigate the energy of reactions that produce LiIO, LiIO3, LiIO4, Li2O2, Li2O, LiOH, and I-2. We find that the most favorable process is the formation of gaseous I-2, coproduced with LiOH or Li2O (depending on the availability of water). If water is absent, then some LiIO4 will also be formed. However, this is unlikely to happen during oxidative dehydrogenation, because LiI is very hydroscopic and the oxidative dehydrogenation reaction produces water.