Carbonylation products such as alkanoic anhydrides, e.g., acetic anhydrides, are produced by carbonylation of esters and ethers in the presence of a rhodium or iridium catalyst and an iodine moiety in a reaction zone wherein {HEAD ~ the reaction mixture} is in {TAIL ~ a continuous boiling state} 
Carbonylation products such as alkanoic anhydrides , e.g. , acetic anhydrides , are produced by carbonylation of esters and ethers in the presence of a rhodium or iridium catalyst and an iodine moiety in a reaction zone wherein { HEAD ~ the reaction mixture } is in { TAIL ~ a continuous boiling state }
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