Prepd by self-condensation of acetophenone in the presence of aluminum tert-butoxide: Adkins, Cox, J. Am. Chem. Soc. 60, 1151 (1938); W. Wayne, H. Adkins, Org. Synth. coll. vol. III, 367 (1955). Use as sunscreen: Ind. Eng. Chem. 46, 15A (July 1954). Toxicity study: H. F. Smyth et al., J. Ind. Hyg. Toxicol. 31, 60 (1949).