in Hydrocarbon Conversion Catalysis
Roddick group in the Department of Chemistry at the University of Wyoming has a
continuing research program focused on organometallic chemistry and homogeneous
catalysis, with a particular emphasis on hydrocarbon conversion chemistry. A synopsis of current research challenges in
this area were outlined in the
Department of Energy's Basic Energy Sciences (BES) Workshop on Basic
Research Needs in Catalysis for Energy Applications, held August 6-8, 2007. This
workshop identified research needs and opportunities for catalysis to meet the
nation's energy needs, provided an assessment of where the science and
technology now stand, and recommended directions for fundamental research that
should be pursued to meet the goals described. Some specific research targets
included (1) selective partial oxidation and functionalization of methane, (2)
oxidative coupling of small hydrocarbons, (3) integrated hydrogen transfer
(hydrogen donation) from methane to hydrogen-poor hydrocarbons, and (4)
selective alkylation and methane homologation strategies. Hydrocarbon
"construction" strategies to form targeted molecules involving multiple C-C
bond formations require catalytic sites with capabilities beyond the limits of
the primary underlying issues in the efficient use of abundant hydrocarbon
resources is the problem of hydrogen balance.
Most desirable from the standpoint of liquid fuels and the chemical
industry are medium-length hydrocarbon chains with a hydrogen:carbon atom ratio
of ~2 (see below). Methane, the
main component of natural gas, has a H:C ratio of 4 and is the primary source
of hydrogen gas through steam reforming.
In contrast, coal has a C:H ratio of ~ 1 and is either used directly as
a fuel or is combined indirectly or directly with hydrogen in coal liquefaction
processes to form desirable hydrocarbons.
Thus, the efficient large-scale production of chemical and fuel
feedstocks is closely tied to the challenge of hydrogen transfer chemistry.
this past year, the Roddick group has published a series of papers detailing
their approach to selective catalytic hydro-carbon hydrogen transfer using a
robust fluorinated metal supporting "pincer" ligand framework. Most notable was a highlighted paper in the journal Organometallics (Organometallics 2011, vol. 30, 5133-5140),
which detailed the first example of a ruthenium-based system for catalytic
this work the only well-defined alkane dehydrogenation catalysts were based on
iridium, a considerably more expensive and less abundant metal. An exciting unique feature of these
fluorinated pincer systems are their unique air and moisture stabilities, which
allow hydrogen transfer reactions to be carried out without special precautions
and the exclusion of air.
primary ruthenium catalysis work was carried out by Brian Gruver, supported
fully by the School of Energy Resources 2008-2010. Brian completed his Ph.D. in the Spring of