III International Conference

PP-I-46normal and branched alkanes but rather changes significantly reaction selectivity. The routeand mechanism of hydrocarbon transformations depends on promoter.Secondary and tertiary butylcations have been registrated for the first time at jointcondensation of aluminum chloride and chloroalkanes (2-chloro-butane and 2-chloro-2-methylpropane), their IR spectra and thermal stability have been studied [1]. Aluminumchloride anions (Al 3 Cl - 10 , Al 2 Cl - 7 or AlCl - 4 ) participating in stabilization of the carbeniumions were revealed. In contrast to tret-butylchloride, which formed carbocation in the courseof co-condensation at 80 K, the creation of the secondary one occured only at elevatedtemperatures. The initial stage of the interaction of aluminum halide with 2-chlorobutane wasformation of unknown earlier molecular complexes, which transformed to ionic species atannealing. The carbocation stabilization by aluminum chloride should provide an opportunityof alkane activation on a classical mechanism of acid catalysis. Really the productcomposition, formed in co-condensates, was close to a set of reaction products in solutions[2]. Light С4-С5 hydrocarbons were mainly formed.The nontrivial way of alkane transformation resulting to creation a normal alkane withsmaller per unit of carbon chain was detected by the action of co-condensates of transitionmetal salt and aluminum halide. For example the basic products of the low temperature n-octane conversion were monomethylheptanes (45-50%), n-heptane (20-35%) and cyclohexane(10-15%). In the aluminum chloride-cobalt chloride system at least 4 different complexes inwhich the coordination number of cobalt varied from 3 up to 6 were detected [3]. Thecomplexes of structure 1:1 and 2:1 were only precursors of the real catalyst; the activeparticles were forming only at interaction of the various kinds of complexes at annealing. Theactivity of such particles was caused by not characteristic coordination numbers of metalatoms. It was found that the presence of coordination unsaturated transitional metal wasresponsible for activation and unusual routes of alkane conversion even under acid catalyst.References1. M.I.Shilina, R.V.Bakharev, V.V.Smirnov. Russ. Chem. Bull., Int. Ed., 2004, 53, 2972. M.I.Shilina, R.V.Bakharev, A.V.Petukhova, V.V.Smirnov. Russ. Chem. Bull., Int. Ed., 2005, 54,1493. M.I.Shilina, R.V.Bakharev, V.V.Smirnov. Doklady Physical Chemistry, 2005, 401, 6392