Characterizing the electronic structure of ionic liquid/benzene catalysts for the isobutane alkylation

When a small amount of benzene was introduced into the chloroaluminate ionic liquid (IL), the IL − alkylation can produce premium alkylation gasoline. In order to deepen our understanding of IL − alkylation in general, the electronic properties of [BMIm][AlCl4]/benzene/reactant system were analyzed by the ADCH charge analysis, DOS analysis, frontier molecular orbital analysis, non − covalent interactions (NCI), and energy decomposition analysis (EDA). ADCH analysis reveals that benzene could markedly affect the charge transfer of alkanes and chloroaluminate anions, which weakened the super−acidity of the IL. Frontier molecular orbital analysis shows that the IL system has a significant decrease of H − Lgap, and it increases the sensitivity of the reactants. The anchoring effect of [BMIm]+ cation was observed in the DOS spectra, which enhanced stabilization of the IL structure. NCI analysis shows that π − H bonds could be formed between benzene and the IL. It is believed that better alkylation performance of IL/benzene system is due to these weak interactions.