Slowdown of H/D Exchange Reaction Rate and Water Dynamics in Ionic Liquids: Deactivation of Solitary Water Solvated by Small Anions in 1-Butyl-3-Methyl-Imidazolium Chloride
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- 作者：Yoshiro Yasaka ; Chihiro Wakai ; Nobuyuki Matubayasi ; Masaru Nakahara
- 刊名：Journal of Physical Chemistry A
- 出版年：2007
- 出版时间：February 1, 2007
- 年：2007
- 卷：111
- 期：4
- 页码：541 - 543
- 全文大小：55K
- 年卷期：v.111,no.4(February 1, 2007)
- ISSN：1520-5215
文摘
The H/D exchange reaction and the rotational dynamics of heavy water (D2O) are studied at 50 
C in theionic liquid, 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), in the [D2O] range of 3-55 M. The initialH/D exchange rates are observed as 1.0 × 10-7, 4.5 × 10-6, 1.0 × 10-5, 4.1 × 10-5, 1.1 × 10-4, and 3.7 ×10-4 s-1, respectively, at [D2O] of 2.8, 7.1, 8.1, 11, 15, and 25 M. The rate is very slow and less than 10-5s-1 at [D2O] below ~7 M. It steeply increases to the order of 10-4 s-1 for 7 M < [D2O] < 10 M, and linearlyincreases with [D2O] in the more water-rich region. The intercept of the linear region at [D2O] = ~9 M isinterpreted by considering that each chloride anion deactivates 1.6 equiv water molecules due to the strongsolvation. Correspondingly, the rotational correlation time of D2O at [D2O] < 7 M is 1 order of magnitudelarger than that in water-rich conditions.
C in theionic liquid, 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), in the [D2O] range of 3-55 M. The initialH/D exchange rates are observed as 1.0 × 10-7, 4.5 × 10-6, 1.0 × 10-5, 4.1 × 10-5, 1.1 × 10-4, and 3.7 ×10-4 s-1, respectively, at [D2O] of 2.8, 7.1, 8.1, 11, 15, and 25 M. The rate is very slow and less than 10-5s-1 at [D2O] below ~7 M. It steeply increases to the order of 10-4 s-1 for 7 M < [D2O] < 10 M, and linearlyincreases with [D2O] in the more water-rich region. The intercept of the linear region at [D2O] = ~9 M isinterpreted by considering that each chloride anion deactivates 1.6 equiv water molecules due to the strongsolvation. Correspondingly, the rotational correlation time of D2O at [D2O] < 7 M is 1 order of magnitudelarger than that in water-rich conditions.