ADSORPTION AND REACTIVE DESORPTION OF C-6 HYDROCARBONS ON PT/SIO2

C6 hydrocarbons (n-hexane, 3-methylpentane, methylcyclopentane) were adsorbed on a well-dispersed Pt/SiO2 catalyst (dpt = 2.4 nm) at 298 and 420 K and subsequently desorbed with a stream of hydrogen in the temperature range 298 to 620 K. Seventy-two to eighty percent of desorption occurred at 298 K and the remainder during heating to 470 K. After adsorption at 298 K, >93% of hydrocarbons desorbed unchanged, but after adsorption at 420 K, only methylcyclopentane desorbed largely unchanged, while n-hexane and 3-methylpentane desorbed predominantly as methylcyclopentane. Implications for the mechanism of nonselective ring opening of methylcyclopentane and cyclic isomerization of C6 hydrocarbons are discussed. © 1990.