PURPOSE: To provide a preparation process of an aromatic organic carbonate wherein an aromatic organic hydroxy compound is directly carbonylated under constant composition gas flow conditions, which employs a recyclable transition metal catalyst which allows introduction of a supplementary amount of the above-mentioned compound into a reactor under ambient conditions.

CONSTITUTION: A transition metal catalyst is used in the form of a palladium catalyst mixture. The palladium catalyst is used in combination with an organic co-catalyst such as terpyridine and a cobalt co-catalyst in the form of a cobalt complex containing a pentadentate ligand. An aromatic organic carbonate formed is separated from a carbonylated reaction mixture as a 1:1 molar adduct of an aromatic organic carbonate such as diphenyl carbonate and an aromatic organic hydroxy compound such as phenol.