Antioxidant properties of 4-vinyl derivatives of hydroxycinnamic acids

► 4-Vinyl derivatives were prepared by thermal decarboxylation of hydroxycinnamic acids. ► Their antioxidant properties were determined under various conditions for the first time. ► Decarboxylation lowered reducing and radical-scavenging capacities of phenolic acids. ► In emulsion derivatives were better antioxidants than phenolic acids. ► Antioxidant activity of compounds in emulsion is mostly defined by their partition.