Fe(SO4)3‐Catalyzed Synthesis of Terpenic Alcohols Esters: A Simple and Bifunctional Reusable Solid Catalyst

• Published in: ChemistrySelect (Weinheim) 2018-06, Vol.3 (21), p.5742-5748
• Main Authors: da Silva, Márcio J., Julio, Armanda A., Mosqueira Ayala, Diego A., de Miranda, Leticia M. P.
• Format: Article
• Language: English
• Subjects: esterification; esters; fragrances; Iron(III); terpenes
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.201800643

Ferric sulfate is a simple and commercially available solid catalyst and demonstrated to be able to catalyze terpenic alcohols esterification with acetic acid, achieving high conversion and ester selectivity. This process is an attractive option to the enzymatic or acid homogenous processes commonly used to synthesize esters. The undesirable steps of neutralizing of the products are avoided. A study of the activity of hydrated Fe2(SO4)3 demonstrated that although the efficiency of the catalyst is directly linked to the ability of the FeIII cations to generate H3O+ ions, the solid catalyst plays also a key role on the esterification process. We assessed the effects of the main reaction variables such as reactants proportion, temperature, and catalyst concentration. Different terpenic alcohols such as β‐citronellol, geraniol, nerol, linalool, α‐terpineol and borneol were esterified in the presence of Fe2(SO4)3 catalyst. The Fe2(SO4)3 catalyst was easily recovered and reused. A simple method for the synthesis of fragrances is described using renewable raw material derivatives (i. e., terpenic alcohols) and acetic acid in solid ferric sulfate‐catalyzed reactions.