Aromatization 3-methylhexane

Normand et al. have studied Pd deposited on several metal oxide supports in reactions of methylcyclopropane hydrogenolysis, 3-methylhexane aromatization, and in Fischer-Tropsch catalysis 23 Three classes of oxides were studied, those that were not reducible such as Re2C>3, those with anion vacancies produced during reduction like Ce02, and those with intrinsic anion vacancies such as nonstoichiometric Pt60h and Tb407. Hydrogenolysis reactions were found to occur on Pd sites whereas aromatization reactions were believed to be... 

Reactions of 3-methylhexane were found to occur on the support alone which complicated the above studies. Besides aromatization to toluene (A), isomerization to cyclopentane derivatives (B), isomerization to heptane and other branched hexanes (C) and cracking to Ci to C6 hydrocarbons (D) were all observed as depicted in Eq. 5.23... 

The formation of wetn-labeled toluene can be explained neither by direct 1-6 ring closure, nor by cyclic-type isomerization of n-heptane to 3-methylhexane followed by 1-6 ring closure of the latter (94). We suggest that the abnormal aromatization process responsible for the formation of meta-labeled toluene is initiated by a dicarbene as in the nonselective mechanism A (see Section IV, Scheme 47). Aromatization is not influenced by the dispersion of the platinum on the support (758), so that it may be assumed that aromatization involves a single metal atom. Isomerization of the dicarbenes (7) to the dicarbenes (8) via rt-adsorbed cyclopentanes, followed by isomerization to the suitable carbene-olefin species (9), would result in 1-6 ring closure and aromatization (Scheme 69). 

Skeletal rearrangements of saturated hydrocarbons on CePd3 were studied by Le Normand et al. (1984). Hydrogenolysis of methylcyclopentane, isomerization of 2-methyl-pentane and aromatization of 3-methylhexane were performed at 350 or 360°C. The results were compared with those of classical Pd/Al203, Pd/Si02 or Pd/Ce02 catalysts. The activity of CePd3 itself was very low and palladium atoms seemed to play a minor role. For example, the initial reaction of methylcyclopentane was the selective formation of isopentane, which is not observed on classical palladium catalysts. Air treatment at... 

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