Sulfuric acid and Amberlyst-H⁺ catalyzed condensation reactions of renewable keto acids with paraformaldehyde: synthesis of a new dispiro bis-lactone ring system 2,9,13-trioxadispiro[4.1.4.3]tetradecane-3,6,10-trione

Abstract

The acid catalyzed condensation of levulinic acid with paraformaldehyde at 80 °C gives 2,9,11,14-tetraoxadispiro[4.1.5.3]pentadecane-3,6-dione, in which the structure was confirmed by X-ray crystallography.

Aldol Condensation of Biomass-Derived Levulinic Acid and Furfural over Acid Zeolites

“…This reaction would allow obtaining a family of C10 compounds with promising uses as fuel additives, surfactants, lubricants or pharmaceutical precursors. 25,26 LA self-condensation has been proposed considering basic and acid materials (mixed oxides, Amberlyst-15, etc. ), concluding that results are strongly conditioned by the competition between the activity of the carbonyl group and the carboxyl one.…”

“…Typically, the carboxylic group of LA plays a key role in the mechanism, with other routes involving the activity of the carbonyl group being scarcely investigated, as is the case of aldol condensation. This reaction would allow us to obtain a family of C10 compounds with promising uses such as fuel additives, surfactants, lubricants, or pharmaceutical precursors. , …”

“…LA self-condensation has been proposed considering basic and acid materials (mixed oxides, Amberlyst-15, etc. ), concluding that results are strongly conditioned by the competition between the activity of the carbonyl group and the carboxyl one. − Thus, more than 30% of angelica lactone (C5) is produced at 323 K, with only 40% LA conversion. The yield of this compound increases with temperature as the main limitation of this procedure …”