Investigation of acid centers in MIL-53(Al, Ga) for Brønsted-type catalysis: in situ FTIR and ab initio molecular modeling.

In contrast to MIL-53(Al), IM-19 (MIL-53 (Ga)) is extremely active and selective for the alkylation of aromatics. The reaction proceeds through the protonation of the aromatic substrate. CO adsorption and molecular modeling show that the bridging μ2-OH of IM-19 exhibits stronger Brønsted-type acidity than does MIL-53(Al).