Currently, the glycerol has been produced in large amounts as biodiesel co-product. Therefore, to develop processes to convert it to more valuable chemicals has attracted significance attention. Glycerol ketals are compounds useful as synthesis intermediates, and fragrances ingredient and mainly, bioadditives for diesel and gasoline, and have been produced trough reactions catalyzed by mineral acids. In this work, we assessed the activity of H 3 PW 12 O 40 heteropolyacid on glycerol ketalization with different ketones at room temperature and in the absence of an auxiliary solvent. The effects of the principal reactional parameters such as the reactants stoichiometry, catalyst concentration, reaction temperature, and type of carbonylic reactant were investigated. H 3 PW 12 O 40 heteropolyacid was much more active than other Brønsted acid catalysts evaluated (i.e. H 2 SO 4 , p-toluenesulfonic acid, H 3 PMo 12 O 40 or H 4 SiW 12 O 40 ) and exhibited high selectivity toward five-membered (1,3-dioxolane) cyclic ketals. Although homogeneous, heteropolyacid catalyst could be recovered and reused without loss activity.

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In this work, efficient solid acid catalysts were obtained from the stoichiometric reactions of Keggin heteropolyacids with SnSO 4 and evaluated in the etherification reactions of glycerol with tert-butyl alcohol (TBA). Among the salts synthesized, the Sn 2 SiW 12 O 40 catalyst was the most active and selective toward glyceryl ethers. High yields of mono-and diglyceryl tert-butyl ethers were achieved after 4 h of reaction at 393 K. The impacts of the main reaction parameters such as stoichiometry of the reactants, catalyst load, time, and reaction temperature were assessed. The efficiency of the Sn 2 SiW 12 O 40 catalyst was also assessed in etherification reactions of ethylene glycol with TBA, and etherification reactions of glycerol with other alcohols (i.e., n-or sec-butyl alcohol, and n-or iso-propyl alcohol). A proposal that describes the reaction pathway including the catalyst participation was also described.

Simple SnCl2·2H2O was demonstrated to be able to catalyze β-citronellol esterification with acetic acid at room temperature under solvent-free conditions, achieving high conversion and ester selectivity (ca. 88% and 99%, respectively).

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 Fe 2 (SO 4 ) 3 demonstrated that although the efficiency of the catalyst is directly linked to the ability of the Fe III cations to generate H 3 O + 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 b-citronellol, geraniol, nerol, linalool, a-terpineol and borneol were esterified in the presence of Fe 2 (SO 4 ) 3 catalyst. The Fe 2 (SO 4 ) 3 catalyst was easily recovered and reused.[a] Prof.