Interactions of hydrocarbons with ambient temperature molten salts

Four molten salts, obtained by combining a bulky organic salt with aluminum chloride, were examined in detail: N-n-butylpyridinium chloride (BuPyCl)/AlCl₃, pyndinium chloride (PyHCl)/AlCl₃, 1-ethyl-3-methyl-1 H-imidazolium chloride (ImCl)/AlC1₃, and trimethylsulfonium bromide ((CH₃)₃SBr)/AlCl₃.; In the present study, emphasis was placed on the comparison of yield obtained under identical conditions. It was hoped that this new use of these ambient temperature molten salts would display the activity, selectivity, and stability required for industrial applications.; In agreement with the consensus in the literature, the data demonstrated that catalytic conversion of hydrocarbons over these melts resulted in two, reactions, cracking and isomerization. The results suggest that carbenium ions are intermediates for all primary reactions. The products from the cracking of heavy paraffins are almost entirely in the C4–C7 range, and the distribution by carbon number is quite similar for all the ionic liquids studied. The distribution was independent of total conversion and experimental conditions. The fragments formed as a result of the paraffin treatment are strongly branched The most important products are those with a single methyl branching which occurs via protonated cyclopropane intermediates.; Formation of the initial carbocation depends on the catalyst used Based on the correlation between the percent conversion and the concentration of Al₂Cl₇− in the ambient temperature molten salts, we believe that the Al₂Cl₇− is the species responsible for the initiation of the reaction through R1-CH2-R2+Al2 Cl^-7&rlhar2;R1- ⁺ CH-R2+AlCl^-4 +AlHCl^-3 ; The ease of cracking or isomerization depends on the strength of the acids used in the reaction. The PyHCl/AlCl₃ system proved to be the most efficient of all the ionic liquid systems studied to crack and isomerize hydrocarbons.; The isomerization of n-butane to iso-butane was also investigated. A high yield of iso-butane was obtained when n-butane was added to the acidic PyHCl/AlCl₃ molten salt. Studies were also undertaken to examine the catalytic conversion of cyclohexane by acidic PyHCl/AlCl₃ molten salts. It was observed that the dominant reaction is the isomerization to produce methylcyclopentane, which accounts for approximately 80% of the total converted cyclohexane. (Abstract shortened by UMI.)...