Nomenclature of  Unsymmetrical Anhydrides

A mixed or unsymmetrical anhydride is a carboxylic acid anhydride that has the following general structural formula.

where R¹≠R², but are hydrogen atoms, alkyl groups, aryl groups. When naming unsymmetrical acid anhydrides, name both using alkanoic general method and then put the two names alphabetically. Hence, first name each component and alphabetically arranged them followed by spaces and then the word anhydride.

propanoic anhydride

ethanoic propanoic anhydride