Cyclohexylation of naphthalene was studied over four commercial unmodi
fied HY zeolites. Approximately equal results were obtained on HY (ZF
515, ZF 520, CBV 720) zeolites. The best results were obtained with cy
clohexylbromide as alkylating agent in n-nonane and in n-decane as sol
vents at boiling point. Conversion of naphthalene was max. 97%, 2,6-se
lectivity 43% and beta,beta'-selectivity 77%.