generating acid through a combination of the proton from H2(g) with a non-coordinating counterion, e.g. trifluoromethanesulfonate (OSO2CF3¯—generally abbreviated as triflate or OTf-) yielding the corresponding acid, in this case HOTf, which then serves as the proton source for both catalytic dehydrations and hydrogenation or hydrogenolysis reactions. Ruthenium and palladium based catalysts, e.g. {[Cp*Ru(CO)2]2(µ–H)}+OTf – (Cp* = η5-C5Me5) and (P-P)Pd(OAc)2, (P-P = bulky chelating diphosphine ligand) of this type being employed in polyol transformations have been reported in the academic [3] as well as the patent literature [4,5] in the past few years, but to date their successes have been limited to the hydrogenation of terminal diol model systems, while their effectiveness with glycerol and higher polyols has so far been marginal. More recently a set of guidelines has been formulated [6] that may aid in the rational and evolutionary design of more active ionic hydrogenation and hydrogenolysis catalysts that address the challenges discussed above. The development of such catalysts will be the key to turning sugar polyols into a new and renewable resource base for the petrochemical industry.
References 1) R. M. Bullock, Chem. Eur. J. 10, (2004), pp. 2366-2374. 2) G. Kubas, Metal Dihydrogen and s-Bond Complexes. Structure, Theory and Reactivity (New York: Kluwer Academic/ Plenum Publishers, 2001). 3) M. Schlaf, P. Gosh, P. J. Fagan, E. Hauptman, R. M. Bullock, Angew. Chem., Int. Ed. 40, (2001), pp. 3887–3890. 4) E. Drent, W. W. Jager, Hydrogenolysis of Glycerol; Shell Oil, Patent WO 09905085, (2000). 5) M. Schlaf, R.M. Bullock, P.J. Fagan, E. Hauptman, Dehydroxylation of Diols and Polyols; Brookhaven National Laboratory, The DuPont Company, Patent WO 0198241 (2001). 6) Z. Xie, M. Schlaf, J. Mol. Cat. A (2005), in press.
Marcel Schlaf, MCIC, is presently an assistant
Call for Nominations to the Canadian Science and Engineering Hall of Fame The Canadian Science and Engineering Hall of Fame was created in 1991 and is now part of the Canada Science and Technology Museum in Ottawa, ON. The objectives are to honour Canadians who have made outstanding contributions to society in developing science and engineering, and to promote role models that will help attract young Canadians to careers in science, engineering, and technology. Nominations for induction to this Hall of Fame can be made by individuals and organizations. Nominations of exceptional chemists, past or present, will be considered. Two or three inductees are selected every year. Inductees will join the ranks of Gerhard Herzberg, FCIC, J. C. Polanyi, FCIC, Raymond Lemieux, FCIC, and Mike Smith, MCIC. Nominations should include as much supporting documentation as possible. The Inductee Selection Committee consists of people from various disciplines, and hence the nomination should be prepared with utmost care and details. Details about the Hall of Fame and the nomination process are available at www.sciencetech.technomuses.ca/english/about/ hallfame/u_main_e.cfm.
professor in the department of chemistry at the University of Guelph.
FEBRUARY 2005 CANADIAN CHEMICAL NEWS 17