Tin(II) Salts: A Versatile and Efficient Lewis Acid Catalyst in Reactions to Add Value to the Glycerol and Terpenic Alcohols

Glycerol is a renewable origin compound that has been generated on a large scale in biodiesel production processes. Terpenic alcohols are abundant raw material present in several essential oils. Therefore, developing processes to convert this cheap feedstock to a more value-added compound is important from an economic and environmental viewpoint. This work summarizes the main advances obtained in different kinds of tin (II) salts-catalyzed reactions in the last decade, where the goal substrates were glycerol and terpenic alcohols. Tin (II) halides are water-tolerant Lewis acids, solid, inexpensive and easy handling, which showed be efficient catalysts in reactions of carbamoylation and ketalization of glycerol, as well as in esterification of terpenic alcohols. The products generated from terpenic alcohol esterification are valuable ingredients for fragrance, agrochemicals and pharmaceutical industries. Conversely, esters and glycerol ketals are useful as fuel additives. Terpenic carbamates are ingredients in agrochemical synthesis. Therefore, due to great success on these reactions, Sn (II) catalysts are an attractive option to the traditional Bronsted acid catalysts.

Keywords: Esterification, Glycerol, Ketalization, Terpenic Alcohols, Tin(II) Catalysts.