Hong, Soon Hyeok (2007) Improvement of olefin metathesis efficiency through understanding catalyst stability. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-04022007-122855
The recent development of ruthenium olefin metathesis catalysts, which show high activity and functional group tolerance, has expanded the scope of olefin metathesis. To improve efficiency of the ruthenium-catalyzed olefin metathesis, this dissertation describes: (1) mechanistic study to understand decomposition pathways of ruthenium olefin metathesis catalysts for the development of more stable and efficient catalysts, (2) a method to prevent an undesirable side reaction for the improvement of selectivity of ruthenium-catalyzed olefin metathesis, and (3) a novel ruthenium catalyst to increase olefin metathesis efficiency in aqueous media for potential biological applications and environmentally friendly approaches to this chemistry.
Chapter 2 describes the first well-characterized decomposition products, dinuclear ruthenium hydride complex and methylphosphonium salt, from an N-heterocyclic carbene-based ruthenium catalyst under typical metathesis conditions. In Chapter 3, the decomposition study was expanded to other widely used ruthenium olefin metathesis catalysts. Phosphine-involvement in the decomposition was consistently observed whether or not an olefin was present. The presence of other decomposition modes for phosphine-free ruthenium catalysts was also described. Chapter 4 addresses another decomposition pathway of an N,N’-diphenylbenzimidazol-2-ylidene-based catalyst via C--H activation. Chapter 6 describes the development of a novel poly(ethylene glycol)-supported water-soluble catalyst, which is active and stable in aqueous media. Chapter 7 describes an efficient, practical, and environmentally friendly method to remove residual ruthenium-containing byproducts by simple aqueous workup from olefin metathesis products using the poly(ethylene glycol)-supported catalyst.
|Item Type:||Thesis (Dissertation (Ph.D.))|
|Subject Keywords:||aqueous olefin metathesis; decomposition; N-heterocyclic carbene; olefin metathesis; ruthenium; ruthenium removal; stability; water-soluble catalyst|
|Degree Grantor:||California Institute of Technology|
|Division:||Chemistry and Chemical Engineering|
|Thesis Availability:||Public (worldwide access)|
|Defense Date:||22 March 2007|
|Non-Caltech Author Email:||pureston (AT) gmail.com|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Imported from ETD-db|
|Deposited On:||02 May 2007|
|Last Modified:||26 Dec 2012 02:36|
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