Detrimental effect of glass sample tubes on investigations of BF4--based room temperature ionic liquid-water mixtures

作者：Saihara Koji; Yoshimura Yukihiro^*; Fujimoto Hideyuki; Shimizu Akio^*

来源：Journal of Molecular Liquids, 2016, 219: 493-496.

DOI：10.1016/j.molliq.2016.03.036

• NMR spectroscopy
• Hydrolysis
• Quaternary ammonium ionic liquid
• Glass sample tube
• Plastic sample tube

Tetrafluoroborate (BF4-)-based ILs are susceptible to hydrolysis due to their hygroscopicity, which complicates their applications. The progress of tetrafluoroborate hydrolysis in a 2 mol% N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate water mixture was investigated by F-19 and B-11 NMR in both glass and plastic sample tubes. In the plastic (polypropylene) tube, hydrolysis reached equilibrium after one day, and the intrinsic hydrolysis was estimated to be 4% relative to the initial amount of BF4-. In contrast, in the glass tube, hydrolysis continued even 15 days after the initial sample preparation due to reaction between glass and HF produced by the hydrolysis of BF4-. Additionally, we found that the dissolution of glass by HF proceeds slowly enough at 4 degrees C that it can be ignored for approximately 1 day. Therefore, experiments using BF4- based ionic liquids can be carried out in glass tube at low temperatures of around 4 degrees C, provided that they are performed quickly following sample preparation, or in plastic tube.

• 出版日期2016-7