CH/π Interaction between Benzene and Hydrocarbons Having Six Carbon Atoms in Their Binary Liquid Mixtures

Molecular interactions between benzene and hydrocarbons having six carbon atoms, such as hexane, cyclohexane and 1-hexene in their binary liquid mixtures were studied through the measurements of density, viscosity, self-diffusion coefficient, C-13 NMR spin-lattice relaxation time and H-1 NMR chemical shift. CH/pi attraction between hexane and benzene in their binary mixture was observed in a relatively benzene rich region, whereas a special attractive interaction was not observed between cyclohexane and benzene. On the other hand, 1-hexene and benzene in their binary mixtures were characteristic in their self-diffusion coefficient behaviors: 1-hexene more strongly attract benzene not only by the CH/pi attraction but also probably by the pi/pi interaction between the double bond in 1-hexene and the pi-electron in benzene ring.