Hydrogen Spillover in Isotopic Exchange Reaction

The high-temperature solid-phase catalytic isotope exchange (HSCIE) reaction in organic compounds, which occurs with the participation of hydrogen spillover (SH), was studied experimentally and with DFT B3LYP and MP2 calculations. The HSCIE reaction yielded deuterium-labeled [D]estradiol, containing, on average, about 7 deuterium atoms per molecule. The isotope distribution and the experimental value of the reaction activation energy were determined using NMR spectroscopy and mass spectroscopy. Using DFT B3LYP, the HSCIE reaction mechanism was studied. The reaction mechanism can be represented as a synchronous one-center mechanism of hydrogen exchange between estradiol adsorbed on the surface of an inorganic substrate and a model charged aluminum oxide cluster, HH⁺(AlO)₃(OH)₆. It was found that DFT calculations on the HH⁺(AlO)₃(OH)₆ catalytic center represent a correct model consistent with the experimental data of the HSCIE reaction.