Study on Ammonia-induced Catalyst Poisoning in the Synthesis of Dimethyl Oxalate

On an industrial plant, we observed and examined the ammonia-poisoning catalyst for synthesis of dimethyl oxalate (DMO). We investigated catalytic activity in response to amount ammonia revealed mechanism such poisoning by X-ray photoelectron spectroscopy (XPS) characterization. Our results show that only 0.002% feed gas can significantly deactivate Pd-based catalyst. Two main reasons were proposed: one is competitive adsorption on active component Pd hinders carbon monoxide (CO) coupling reaction redox cycle between Pd0 Pd2+; other high-boiling nitrogen-containing amine compounds formed reacting with have adsorbed catalyst, which progress reaction. The deactivation caused latter irreversible. be completely restored a low-temperature liquid-phase in-situ regeneration treatment. Copyright © 2021 Authors, Published BCREC Group. This open access article under CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).