| METHOD |
Chemists at Co. demonstrated that [bmim][PF6] & related IONIC LIQUIDS are effective media for RING-CLOSING METATHESIS of DIENES using neutral ruthenium carbene catalysts: (Cl)2[P(Cy)3]2Ru=CH-Ph; Cy = cyclohexyl The catalysts used were discovered years ago by Grubbs Robert H., chemistry prof at California Institute of Technology. They are a family of highly reactive Ru complexes that are tolerant of most organic functional groups & asre stable in air & water. The catalysts are used widely not only for ring-closing metathesis but also to prepare polymers from cyclic alkenes by ring-opening metathesis polymn. “The use of Grubbs catalysts in INDUSTRIAL processes is severely hampered by the resulting Ru contamination in ring-closed prodt”. The present work shows that ionic liquids such as [bmim][PF6] significantly reduce this contamination. “The ring-closed prodt is easily extracted from the ionic liquid using DIETHYL ETHER, without extracting the catalyst. As a result, it is possible to reuse the catalyst & the ionic liquid for at least 3 cycles” The researchers established the general applicability of the technique by carrying out ring-closing metathesis of several dienes in [bmim][PF6]. They showed that conversions in ionic liquids were equal to, if not better than, conversion in traditional solvents such as CH2Cl2 or toluene. For example the group achieved 100% yield for the metathesis of DIETHYL DIALLYL MALONATE to the corresponding CYCLOPENTENE. |
| UPDATE | 03.02 |
| AUTHOR | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
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