Title
Raman investigation on the local structure of alcohols in 1-butyl-3-methylimidazolium tetrafluoroborate
Author
Yukihiro Yoshimura, Takahiro Mori, Kazuyoshi Kaneko, Shuji Hattori, Takahiro Takekiyo, Yuichi Masuda, Akio Shimizu
Year
2019
Journal
Journal of Molecular Liquids
Abstract
In this study, we investigated the evolution of the local structure of a series of primary alcohols from methanol to octanol in 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) as a function of alcohol concentration using Raman spectroscopy, with the aim of gaining more insight into the fundamentals of the compelling ionic liquid–molecular solvent interactions at molecular level. The Raman spectra revealed the presence of various types of OH species in the mixtures, with the major fractions at low alcohol concentration corresponding to monomers, which indicates that most of the alcohol molecules are isolated from each other. A plausible picture for the changes in the local structures of alcohol molecules loosely confined in the [bmim][BF4] matrix is presented, which suggests the occurrence of conformational changes in the bmim+ cation and the alcohol molecules. This observation may indicate a unique evolution of the local structure of alcohol clusters formed in the ionic liquid.
Instrument
NRS-5100
Keywords
Raman imaging microscopy, Ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate, Primary alcohols, Raman spectroscopy, Conformational change, Alcohol clusters