Oxidative carbonylation of amines with alcohols provides an environmentally benign pathway to isocyanates and carbamates. Currently, the most active catalysts for the oxidative carbonylation of aniline with methanol are Pd-based catalysts. To further improve the economic feasibility of the carbamate synthesis process, we have investigated the activity of CuCl₂–NaI, CuCl₂–NaCl, and CuCl–NaI at 438 K and 0.41 MPa by in situ infrared spectroscopy. The activity of the catalysts for carbamate synthesis increased in the order: CuCl₂–NaCl < CuCl–NaI < CuCl₂–NaI. The presence of promoter (i.e., NaI or NaCl) in the reactant–catalyst mixture is essential to promote carbamate synthesis. The formation of by-product, CO₂, can be suppressed by the sequential addition of NaI to CO/O₂/methanol/aniline/CuCl₂. Transient profiles of reactants/products obtained from in situ infrared spectroscopic studies revealed that CO₂ and carbamate were formed via two independent pathways. The infrared observation of a Cu⁰(CO)₂ species and O₂ participation in carbamate synthesis suggest that the carbamate synthesis reaction involves a redox cycle of Cu⁰/Cu^II.