Function alization of Polyisobutylene and Polyisobutylene Oligomers via the Ritter Reaction

摘要

The Ritter reaction, or the reaction of a carbocation in the presence of a nitrile substrate, was conducted on a series of polyisobutylene (PIB) substrates using a variety of reaction conditions. Capping reactions of living PIB carbocations were attempted using acrylonitrile under living polymerization conditions (methyl chloride/hexane 60/40 (v/v) solvent mixtures at -70 °C) resulting in either terf-chloride end groups or loss of chain end fidelity via carbocation rearrangement, as evidenced by NMR spectroscopy, fxo-olefin functionalized PIB substrates were also used in the presence of various acids, solvents, and nitrile substrates, resulting in either exo-olefin PIB or PIB that had undergone severe backbone degradation, as measured via NMR spectroscopy and gel permeation chromatography. Finally, the Ritter reaction was performed on a series of exo-olefin functionalized small molecule PIB distillates using either acrylonitrile as the solvent/nitrile source, or a 60/40 dichloromethane/hexane solvent system. When dissolved in acrylonitrile, carbocation rearrangement of the PIB distillate chain end was largely suppressed, resulting in smooth formation of the terminal acrylamide. Under dilute conditions, significant carbocation rearrangement and degradation of the oligomer backbone resulted in a variety of acrylamide functionalized oligomers and their isomeric derivatives.