Reaction of acetaldehyde with zirconium: A density functional theoretical study

The reaction mechanism of the Zr atom with CH3CHO has been investigated with a DFT approach. All the stationary points are determined at the UB3LYP/ECP/6-311++G** level of the theory. Both ground and excited state potential energy surfaces are investigated in detail. The present results show that the title reaction start with the formation of a η2-CH3CHO-metal complex followed by CC, aldehyde CH, methyl CH and CO activation. These reactions can lead to six different products (HZrCH3 + CO, ZrCO + CH4, ZrCH2CO + H2, ZrCOCH3 + H, ZrCH2CHO + H and ZrO + C2H4). The minimum energy reaction path is found to involve the spin inversion in the initial reaction step. This potential energy curve-crossing dramatically affects reaction exothermic. As the triplet intermediates, transition states and products involved in the reaction lie below the ground reactants (Zr(5F) + CH3CHO), the reaction is expected to occur spontaneously over the triplet potential energy surface. The present results may be helpful in understanding the mechanism of the title reaction and further experimental investigation of the reaction.