Formation of heavy adducts in esterification of acrylic acid: A DFT study

► Esterification of acrylic acid with alcohols and the side reactions were studied at the B3LYP/6-31G** level. ► The activation barriers for esterification decrease significantly in presence of the H+ ion. ► The lowest activation barrier of the side reaction is for acrylic acid addition to acrylates double bond. ► The additions of water and alcohols to acrylates are the next easily occurring side reactions. ► Acrylic acid dimerisation and addition of alcohol to the dimer proceed through higher activation barriers.