Upgrading Light Hydrocarbons: A Tandem Catalytic System for Alkane/Alkene Coupling

摘要: Light hydrocarbons, with relatively low fuel value, are abundant from several sources, including mixed alkane/alkene refinery byproduct streams. A tandem system consisting of a compatible combination homogeneous alkane dehydrogenation catalyst (known to be kinetically efficient but thermodynamically disfavored at temperatures) an olefin dimerization could effect the coupling and alkene produce heavier, more valuable molecule (C_nH_(2n+2) + CnH_(2n) = C_(2n)H_(4n+2)), reaction that is favorable below 250 °C. We have demonstrated catalyst, pincer-ligated iridium organometallic tantalum catalyst; couples 1-hexene/n-heptane C_(13)/C_(14) products temperatures ranging 100 150 °C, operating up 90 % cooperativity. This particular generates rather than desired alkanes, however, because regioselectivity preferentially yields highly substituted alkenes not reactive towards hydrogen transfer. complete cycle should attainable by combining alternate gives mostly linear monosubstituted alkenes; we synthesized novel class nickel-exchanged zincosilicates exhibit catalytic behavior.