Influence of different alkyl and carboxylate substituents on Sn(IV) organometallic catalysts during fatty acid methyl ester production

• Complexes of Sn(IV) bearing different alkyl and carboxylate ligands were tested.
• All complexes tested are active in esterification and transesterification.
• Reactivity is associated to steric and electronic effects imposed by the ligands.

Sn(IV) complexes (dimethyltin dineodecanoate (1), dibutyltin dineodecanoate (2), dioctyltin dineodecanoate (3), dimethyltin diundec-10-enoate (4), dibutyltin diundec-10-enoate (5), tributyltin undec-10-enoate (6) and tributyltin undecanoate (7)) were tested as catalysts for transesterification or esterification in the presence of methanol, in order to investigate the effect of the substituents coordinated to the metal center. All complexes were active at relative high reaction temperatures, and their reactivity can be associated with the steric effects induced by the substituents (alkyls and carboxylates) at the metal center.