title: NMR Characterization of Ionicity and Transport Properties for a Series of Diethylmethylamine Based Protic Ionic Liquids.
abstract: The ionicity and transport properties of a series of diethylmethylamine (DEMA) based protic ionic liquids (PILs) were characterized, principally utilizing nuclear magnetic resonance (NMR) spectroscopy. PILs were formed via the protonation of DEMA by an array of acids spanning a large range of acidities. A correlation between the (1)H chemical shift of the exchangeable proton and the acidity of the acid used for the synthesis of the PIL was observed. The gas phase proton affinity of the acid was found to be a better predictor of the extent of proton transfer than the commonly used aqueous ΔpKa. Pulsed field gradient (PFG) NMR was used to determine the diffusivity of the exchangeable proton in a subset of the PILs. The exchangeable proton diffuses with the acid if the PIL is synthesized with a weak acid, and with the base if a strong acid is used. The ionicity of the PILs was characterized using the Walden analysis and by comparing to the ideal Nernst-Einstein conductivity predicted from the (1)H PFG-NMR results.
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Davidowski
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Forrest
authors.initials: F
authors.lastname: Thompson
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hasani
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Samrat A
authors.initials: SA
authors.lastname: Amin
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: C Austen
authors.initials: CA
authors.lastname: Angell
authors.affiliation: School of Molecular Sciences and the Magnetic Resonance Research Center, Arizona State University , Tempe, Arizona 85287-1604, United States.
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Yarger