A novel and efficient process for preparation of 2,4-diphenyl-4-methyl-1- pentene in brönsted acidic ionic liquid [Hmim]⁺BF ₄^-

Highly selective dimerization of α-methylstyrene (AMS) was effected using a Brönsted acidic ionic liquid, [Hmim]⁺BE₄ ^-, as solvent as well as catalyst, providing the industrial high-value olefin, 2,4-diphenyl-4-methyl-1-pentene (1-PT). The desired dimer 1-PT could be obtained in 90% yield at 96% conversion in the dimerization of AMS under optimized conditions. Features of the procedure include use of readily available ionic liquid-catalyst, exclusion of volatile organic solvents, higher selectivity and efficiency for 1-PT.