CHEMREACTOR-21: XXI International Conference on Chemical Reactors. September 22-25, 2014 in Delft, The Netherlands. ISBN 978-5-906376-06-0. Website: http://conf.nsc.ru/CR-21-2014/en
PP-13 METHYLTRIOXORHENIUM SUPPORTED ON MESOPOROUS Al2O3 PROMOTED WITH ZnCl2 AS A GREEN HETEROGENEOUS CATALYST FOR METHYLOLEATE SELF-METATHESIS: REACTION KINETICS Abdelnasser Abidli1,3, Subha Kumaraswamy Pillai1,2, Safia Hamoudi1, Khaled Belkacemi1,* 1
Department of Soil Sciences and Food Engineering; 2Department of Chemical Engineering; Department of Food Sciences and Nutrition, Laval University, Québec, Canada, G1V 0A6
3
*
[email protected] Fats and oils containing carbon-carbon double bonds can undergo transformation via metathesis to introduce new chemical functionality or to alter reactant properties enabling synthesis of a wide range of reaction products from pharmaceuticals and cosmetics to polymers and fine chemicals [1]. This metathesisbased modification of fats and oils is regarded as a clean and green catalytic and atom-efficient reaction giving rise to industrially important products without by-product formation [2]. Well-defined homogeneous catalysts are compatible with a wide range of functional groups. These catalysts based on group 6 and 7 transition metals present the advantage of working at rather low temperatures (25–80 oC), giving rise to good selectivity and activities [3]. However, high costs and decomposition hinder their recycling or regeneration. Heterogeneous catalysts, typically from group 6–7 oxides supported on large surface area oxide supports, are robust and can be regenerated by simple calcination. However, they are generally not active with functional groups such as olefin esters unless activators are used [4]. The well-known heterogeneous catalytic system Re2O7/Al2O3 promoted by R4Sn is relatively active but is susceptible to poisoning by Sn, which hampers its regeneration [5].
Nonetheless, metathesis of functionalized olefins such as methyloleate and other unsaturated esters such as bulky triglycerides using catalysts supported on mesoporous materials remains largely unexplored. Recently, we demonstrated for the first time that MTO/ZnCl2-modified mesoporous Al2O3 is an efficient catalyst for the metathesis of methyloleate, a model molecule of bulky triglycerides present in fats and vegetable oils [6, 7]. This work focuses on Al/Zn molar ratio effect of on the activity and selectivity of the catalyst towards the desired products and also presents the self-metathesis kinetics of methyloleate over this heterogeneous catalyst. Methyltrioxorhenium impregnated on ZnCl2-modified mesoporous alumina at Al/Zn ratio of 8-12 was revealed as an effective catalyst for self-metathesis of methyloleate at mild reaction conditions. This research suggests that it is possible to design a stable and green heterogeneous
catalyst
for
the
efficient
and
selective
self-metathesis
of
functionalized olefins such as methyloleate and edible oils, avoiding the utilization of expensive homogeneous catalysts or use of toxic promoters such as R4Sn. References [1]
H. L. Ngo, K. Jones, T. A. Foglia, J. Am. Oil Chem. Soc., (2006), 83, 629-634.
[2] M.A.R Meier, J.O. Metzger, U.S. Schubert, Chem. Soc. Rev., (2007), 36, 1788-1802. [3] A. H. Hoveyda, A. R. Zhugralin, Nature, (2007), 450, 243-251. [4] Y. Iwasawa, H. Ichinose, S. Ogasawara, M. Soma, J. Chem. Soc. Faraday Trans., (1981), 77, 1763-1777. [5] R Buffon, U. Schuchardt, J. Chem. Soc. Faraday Trans., (1995), 91, 3511-3517. [6] S. K. Pillai, S. Hamoudi, K. Belkacemi, Fuel, (2013), 110, 32-39. [7] S. K. Pillai, S. Hamoudi, K. Belkacemi, Applied Catalysis A-General, (2013), 455, 155– 163.
Acknowledgements The authors gratefully acknowledge the Natural Sciences and Engineering Research Council of Canada who provided funds for this research.
