Photochemical Products of trans-Cinnamic Alcohol: Possible Formation of Skin Irritants and Allergens

Abstract

trans-Cinnamic alcohol, a potentially phototoxic fragrance material, was irradiated with an ultraviolet (W) lamp in aqueous solution or natural sunlight in ethanol solution. Photochemical products were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GUMS). Formation of products was evaluated over time in the presence and absence of oxygen. The major products formed under nonoxidative conditions were cis-cinnamic alcohol and cinnamic alcohol rearrangement products, 3-phenylpropanal and 1-phenyl-2-propenol. Small quantities of ben-zaldehyde and 3-phenylpropanoic acid were also produced. In the presence of oxygen, small amounts of cinnamaldehyde were produced but no cinnamic acid was detected. Sunlight irradiation of trans-cinnamic alcohol in ethanol showed slow rates of production of cis-cinnamic alcohol, 3-phenylpropanal, and benzaldehyde. Benzaldehyde and cinnamaldehyde are reportedly potential skin irritants or allergens.