Ultrafast structure and dynamics in ionic liquids: 2D-IR spectroscopy probes the molecular origin of viscosity

The viscosity of imidazolium ionic liquids increases dramatically when the strongest hydrogen bonding location is methylated. In this work, ultrafast two-dimensional vibrational spectroscopy of dilute thiocyanate ion ([SCN] -) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4C1im][NTf2]) and 1-butyl-2,3- dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([C4C 1C12im][NTf2]) shows that the structural reorganization occurs on a 26 ± 3 ps time scale and on a 47 ± 15 ps time scale, respectively. The results suggest that the breakup of local ion-cages is the fundamental event that activates molecular diffusion and determines the viscosity of the fluids. © 2014 American Chemical Society

Flora of the Nichols Arboretum, Ann Arbor, MIa thesis submitted in partial fulfillment ... for th

Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/101638/1/39015052696229.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101638/2/39015052696229.pd

Efficient Polymerization Inhibition Systems for Acrylic Acid Distillation: New Liquid-Phase Inhibitors

Phenothiazine and other compounds with similar structures, namely, phenoxazine, promazine, promazine hydrochloride, <i>N</i>,<i>N</i>′-dimethylphenazine, carbazole, <i>N</i>-ethylcarbazole, <i>N</i>-benzylphenothiazine, and <i>N</i>-(1-phenylethyl)­phenothiazine were tested as liquid-phase inhibitors for acrylic acid. N-Alkylated phenothiazine (PTZ) derivatives, such as <i>N</i>-benzylphenothiazine and especially <i>N</i>-(1-phenylethyl)­phenothiazine, showed improved efficiency for liquid-phase inhibition, in comparison with PTZ. It was also shown that N-alkylated PTZ derivatives could be used in combination with nitroso compounds that can be employed as vapor-phase inhibitors. The combination of <i>N</i>-(1-phenylethyl)­phenothiazine and nitrosobenzene showed superior liquid-phase-inhibition efficiency, with time to gelation of >122 h, in comparison with 64 h obtained with PTZ alone. The structure of liquid-phase inhibitors had no influence on the extent of Michael addition reactions during heating of acrylic acid