Reductive functionalization of carbon nanomaterials
Billups, W. E.
Doctor of Philosophy
Since the development of techniques to functionalize single-walled carbon nanotubes (SWNTs), researchers have focused on the use of this methodology to solubilize other nanomaterials including graphite and large fullerenes. This thesis presents a convenient and scalable route to these soluble materials. The large fullerenes that are formed during the synthesis of C 60 by the arc discharge technique were solubilized by reductive alkylation. The dodecylated derivatives are soluble in common organic solvents and show unusual NMR characteristics in the solid state. SWNTs were functionalized by nitrogen and oxygen centered free radicals using the reductive functionalization approach. The derivatized SWNTs were then hydrolyzed to give amine and hydroxy functionalized SWNTs. In the presence of cyclic disulfides, SWNT salts initiate a single electron transfer (SET) reaction to give SWNTs functionalized by free thiol groups. Phenyl radicals generated by the decomposition of benzoyl peroxide have been used to derivatize graphite. The resulting phenylated material was then sulfonated by oleum (H 2 SO 4 , 20% free SO 3 ) leading to exfoliated graphene, which is soluble in water. In another study, large-scale production of lithium intercalated graphene sheets was carried out by the reduction of exfoliated graphite oxide using Li/NH 3 . Soluble activated charcoal was synthesized by reductive dodecylation and found to be soluble in most organic solvents. Finally, coal was alkylated by dodecyl groups to give soluble "nanocoal". It was found that the lithium salts of coal serve as a source of electrons to induce in-situ polymerization of simple alkenes (1- dodecene) onto the surface of the coal nanoplatelets to give a new composition of matter (part coal, part oil).
Organic chemistry; Pure sciences; Carbon nanotibes; Fullerenes; Reductive functionalization