Preparation and characterization of a ruthenium(II) catalyst for radical polymerization of olefins.

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Title: Preparation and characterization of a ruthenium(II) catalyst for radical polymerization of olefins.
Author: Arrowood, Benjamin Nathan
Advisors: T. Brent Gunnoe, Committee Chair
James D. Martin, Committee Member
Christopher B. Gorman, Committee Member
Abstract: A ruthenium(II) complex TpRu(CO)(CH3)(NCCH3) (Tp = hydridotris(pyrazolyl)borate) was prepared from TpRu(CO)2(CH3) by refluxing in acetonitrile with (CH3)3NO. Heating a solution of TpRu(CO)(CH3)(NCCH3) in CDCl3 to 50 oC with various equivalents of CD3CN indicates that the Ru-NCCH3 undergoes exchange with CD3CN and is independent of CD3CN concentration. Reactions with styrene or methyl methacrylate in the presence of catalytic quantities of TpRu(CO)(CH3)(NCCH3) at 90 °C result in the production of polystyrene and polymethyl methacrylate, respectively. An inverse dependence of polystyrene molecular weight on concentration of added cumene indicates that a radical polymerization mechanism is likely. In addition, the polymerization of styrene or methyl methacrylate occurs in the presence of carbon tetrachloride or methyl dichloroacetate with catalytic quantities of TpRu(CO)(CH3)(NCCH3) at 90&deg. In both cases, polymer conversion rates are sluggish and molecular weight distributions are broad. The slow reaction rates are attributed to a high Ru(III/II) redox couple that favors Ru(II). Reactions with TpRu(CO)(CH3)(NCCH3) in benzene charged with ethylene at 90 °C do not produce polyethylene. Rather, catalytic synthesis of ethylbenzene as well as 1,3- and 1,4-diethylbenzene is observed.
Date: 2003-04-17
Degree: MS
Discipline: Chemistry
URI: http://www.lib.ncsu.edu/resolver/1840.16/2928


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