La-Stabilized, Single-Atom Ir/AC Catalyst for Heterogeneous Methanol Carbonylation to Methyl Acetate

Although homogeneous methanol carbonylation is industrialized to produce acetic acid, it still suffers from the problems of difficult separation and metal leaching. Here, we report a heterogeneous single atom Ir-La/AC catalyst to produce methyl acetate in a fixed-bed reactor. A high TOF of 2200h(-1) and high selectivity over 90% for methyl acetate with space time yield of 8200 g/(kg(cat) h) were achieved over the Ir-La/AC catalyst. Furthermore, the effects of reaction temperature, partial pressure of CO and CH3OH, weight ratio of CH3I/CH3OH, total LHSV as well as the role of La on the catalytic performance of Ir/AC were tested in this paper. In addition, we proposed a reasonable mechanism for heterogeneous methanol carbonylation over La stabilized single atom Ir/AC catalyst. Our work provides a reference for the further scale-up of the process and a stable, supported, single-atom system as a substitution for other homogeneous catalyst.