End Functinalization of Polyisobutylenes and their Applications in Dyeing Polyolefins and in Homogeneous Catalysis
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Non-polar phase selectively soluble polyisobutylene (PIB) is a useful polymer as a polymer support for homogeneous catalysts. Substitution of PIB onto other useful ligands alters the solubility properties of original ligands. However, such chemical modification of PIB polymers is challenging due to its limited synthetic availability. This dissertation describes the end functionalization of this terminal alkene functionalized PIB into variety of other functional groups via variety of chemistries such as electrophilic aromatic substitutions, nucleophilic aromatic substitution reactions and alkylation reactions. PIB-anilines and PIB-phenols can be prepared via electrophilic aromatic substitution reactions of anilines and phenols by PIB-alkene. Excellent oxidative and chemical resistance and nonpolar phase selective solubility of these modified PIB polymers allow these materials to be useful as soluble polymer supports for ligands and transition metal catalysts. This dissertation details immobilization of palladium and ruthenium catalysts on to these modified PIB ligands and their catalytic properties and catalyst recyclability. PIB-bound palladium catalyst was used as a recyclable homogeneous catalyst for cross coupling reactions in a thermomorphic liquid/liquid separation system- biphasic at a lower temperature and monophasic at a higher temperature. Application of a ‘solid solvent’-(Polywax) in place of a organic solvent is also described and improved metal sequestration of this liquid/solid catalyst/product separation compared to the thermomorphic liquid/liquid separation strategy is also investigated. A PIB-bound ruthenium visible light photo-redox catalyst was prepared and its catalytic activity and recyclability in free radical polymerization reactions of acrylates is also reported. At the end this dissertation details the extension of PIB’s utility as a nonpolar phase anchor to functionalize polyolefins with dyes. This is illustrated by preparing PIB-bound metallophthalocyanine dyes in a series of reactions starting with 4-nitro phthalonitrile. The non-polar solvent solubility of these dyes allowed their use in dyeing commercial polyethylene and polypropylene.
Boralugodage, Nilusha P (2013). End Functinalization of Polyisobutylenes and their Applications in Dyeing Polyolefins and in Homogeneous Catalysis. Doctoral dissertation, Texas A & M University. Available electronically from