630 likes | 1.28k Views
Organic Building Blocks Derived From Carbon Dioxide . Nickeisha Stephenson Stahl and Gellman groups October 25 th 2007. The Carbon Cycle. Since the pre industrial era CO 2 levels have risen from 270 ppm-380 ppm. http://www.eo.ucar.edu/kids/green/images/carboncycle_sm.jpg
E N D
Organic Building Blocks Derived From Carbon Dioxide Nickeisha Stephenson Stahl and Gellman groups October 25th 2007
The Carbon Cycle Since the pre industrial era CO2 levels have risen from 270 ppm-380 ppm http://www.eo.ucar.edu/kids/green/images/carboncycle_sm.jpg Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Where is our excess CO2 coming from Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Industrial Sources of Carbon 1013 tons of carbon finite resource Atmosphere – 1014 tons carbon Carbonates -1016 Tons carbon
CO2 usage industrially Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Large Available Carbon Feedstock CO2Chemically Transformed Annually 120Mt Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Carbon Dioxide Thermodynamics CO2 is carbon in its most oxidized form Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
In Other Words In order to make CO2 into a useful compound, energy needs to be supplied to reduce the oxidized species Sakakura, T. Choi J-C., Yasuda, H.Chem. Rev. 2007, 107, 2365-2387
MO Diagram CO2 • Salahub, D.R. and Russo, N., Metal Ligand Interactions: From atom Clusters, to surfaces, 1991; p 175-197
Some Not So Unfamiliar Reactions Of Carbon Dioxide Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Relative Rates of Insertion PMe3 > PPh3 Increasing the basicity of the phosphine ligand, increases electron density on the metal, allowing for faster CO2insertion Kolomnikov, I.S., Gusev, A.O., Belopotapova, Grigoryan, M.Kh., Lysyak, T.V., Struchkov, Yu. T., Volpin, M.E J. Organometallic Chem., 1974, 69, C10-C12
Me > Ph Decreasing electron withdrawing ability of R group, increases electron density at the metal center, thereby increasing CO2insertion Darensbourg, D., Grötsch, G., Wiegreff, P., Rheingold, A, Inorg. Chem., 1987, 26, 3827-3830
Benzoic Acid and Methyl Benzoate Formation Reaction not catalytic Kolomnikov, I.S., Gusev, A.O., Belopotapova, Grigoryan, M.Kh., Lysyak, T.V., Struchkov, Yu. T., Volpin, M.E J. Organometallic Chem., 1974, 69, C10-C12
Catalytic Formation of Benzoic Acids Ukai, K., Aoki, M., Takaya, J., Iwasawa, N., J. Am. Chem. Soc. 2006, 128, 8706-8707
Ukai, K., Aoki, M., Takaya, J., Iwasawa, N., J. Am. Chem. Soc. 2006, 128, 8706-8707
Organic Carbonates • Polycarbonate Synthesis • Solvent • Fuel Additive • Carbonylating and Alkylating agent • High boiling solvents • Reactive intermediates • Cosmetics • Antifreeze • Electronics • Optical media • Sheeting • Water Bottles • 2.7 million tons produced annually http://img.alibaba.com/photo/50047975/Dimethyl_Carbonate.jpg
Organic Carbonate Production Dimethyl Carbonate Cyclic Carbonates Polymeric Carbonates Tundo, P., Selva, M. Acc. Chem. Res. 2002, 35, 706-716 ukuoka, S., Kawamura, M., Komiya, K., Tojo M., Hachiya, H., Hasegawa, K., Aminaka, M., Hirosige O., Fukawa, Konno, S Green Chemistry, 2003, 5, 497-507
Phosgene Used as a chemical weapon during WWI MAK = maximum allowable concentration in the work place LC50 = Concentration lethal to kill 50% of a population Leitner, W. Angew. Chem. Int. Ed. Engl. 1995, 34, 2207-2221
Dimethyl Carbonate: Phosgene Substitute But… Tundo, P., Selva, M Acc. Chem. Res. 2002, 35, 706-716 Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
Overcoming Thermodynamics • Adding drying agents to remove water - Na(SO4)4, MgSO4, dicyclohexylcarbodiimide, PPh3 and molecular sieves did not help reaction • Dehydrating methanol, to eliminate the production of water 88% yield Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
Redesigning the experimental set up 46% yield Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
Heterogeneous Systems Ree. M, Bae, J.Y., Jung, J.H., Shin, T.J J. Polym. Sci. Part A 1999, 37, 1863-1876
Zinc Glutarate Catalysis Ree, J. Cat 2003, 218, 386 Darensburg, Chem Rev. 2007, 107, 2388
Salen complexes for polymerization Reaction shows a first order dependence on catalyst Darensbouorg, D.J., Yarbrough, J.C.J. Am. Chem. Soc. 2002, 124, 6335-6342
Initiation Propagation
Cyclic Carbonate Formation Paddock R.L., Nguyen, S.T, J. Am. Chem. Soc.2001, 123, 11498-11499
Formic Acid • 300,000 tons of formic acid produced annually - Silage for animal food - Coagulant for latex rubber - Food additive - Tanning and dyeing http://en.wikipedia.org/wiki/Image:Concrete-stave-silo.jpg, http://www.italymag.co.uk/images/bags1.jpg, http://www.osha.gov/SLTC/etools/hospital/hazards/images/latex.jpg
Formic Acid Production Current Industrial Route Alternate Route One Pot Synthesis of Derivatives Leitner, W., Angew Chem. Int. Engl.1995, 34, 2207-2221
Unfavorable Thermodynamics Jessop, P.G., Tako, I., Noyori, R., Chem. Rev. 1995, 95, 259-272
HCO2H Yield (mol/ mol cat.) Water added (mmol) Initial Catalytic System Hydrolysis rate determining step TOF = turn over frequency= mol HCOOH/ mol catalyst h-1 Inoue, Y., Izumida, H., Sasaki,Y., Hashimoto, H., Chem. Lett.,1976, 863-864
Proposed Mechanism Rate determining step Inoue, Y., Izumida, H., Sasaki,Y., Hashimoto, H., Chem. Lett.,1976, 863-864
Effects Base on Hydrogenation Reaction Base must be capable of deprotonating and stabilizing formic acid Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
Effects of Protic Source Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
Putting the Pieces Together HCO2H yield (mol per mol NR3) pKa • Effective alcohols have aqueous pKa’s below that of the protonated amine • Alcohols may help to facilitate CO2 insertion Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
Hydrogenation of CO2 • Despite the unfavorable thermodynamics for the hydrogenation of CO2 addition of an appropriate base and alcohol helps to over come these barriers • Another strategy in bringing about CO2 hydrogenation would be to carry out the reaction in supercritical CO2
Supercritical CO2 Critical point (C) CO2 Temperature = 31.0°C Pressure = 73.75bar http://www.chemguide.co.uk/physical/phaseeqia/pdco2.gif
Increased Rates Observed in ScCO2 Jessop, P.G., Tako, I., Noyori, R. Nature, 1994, 368, 231-233 Jessop, P.G., Hsiao, Y., Ikariya, T., Noyori, R., J. Am. Chem. Soc., 1996, 118, 344-355 Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc., 124, 7963-7971
Methyl Formate TOF = 68 h-1
Formamides Addition of amine to the formic acid reaction results in the formation of formamides Jessop, P.G., Hsiao, Y., Ikariya, T., Noyori, R., J. Am. Chem. Soc., 1996, 118, 344-355
Conclusions • Carbon dioxide is kinetic and thermodynamically stable, however, it can be activated in the presence of strong nucleophiles and metal complexes with high electron density at the metal center • Insertion into a metal- element bond (M-C, M-H and M-O) leads to the formation of new compounds that can react further to produce more interesting compounds • The field of carbon dioxide utilization is still in its infancy, but it needs to grow up in order to alleviate our dependence on fossil fuels. This can only come with further research and more academic interests in this field.
Future directions • Mechanistic studies to better understand the role of additives and the elimination of carboxylate and catalyst regeneration in order to build better catalysts • It would be ideal to carry out these reactions efficiently under 1 atm of CO2 • Development of new reactions • Coupling coordination chemistry with electrochemistry