{HEAD ~ Carbonylation products} such as alkanoic anhydrides, e.g., {TAIL ~ 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 the reaction mixture is in a continuous boiling state 
such as
{ HEAD ~ Carbonylation products } such as alkanoic anhydrides , e.g. , { TAIL ~ 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 the reaction mixture is in a continuous boiling state
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