物理化学学报 >> 2011, Vol. 27 >> Issue (04): 971-976.doi: 10.3866/PKU.WHXB20110421

光化学和辐射化学 上一篇    下一篇

离子液体[bmim][BF4]对联苯甲酰光化学反应影响的瞬态吸收光谱

朱光来1, 吴国忠2, 崔执凤1, 许新胜1   

  1. 1. 安徽师范大学原子与分子物理研究所, 安徽 芜湖 241000;
    2. 中国科学院上海应用物理研究所, 上海 201800
  • 收稿日期:2010-11-01 修回日期:2010-12-20 发布日期:2011-03-29
  • 通讯作者: 朱光来, 吴国忠 E-mail:wuguozhong@sinap.ac.cn; zhglai@mail.ahnu.edu.cn
  • 基金资助:

    国家自然科学基金(20673137, 20903004), 安徽高校省级自然科学研究重点项目(KJ2010A145)及安徽师范大学博士启动基金资助

Transient Absorption Spectroscopy of the Effects of the Ionic Liquid [bmim][BF4] on the Photochemical Reactions of Benzil

ZHU Guang-Lai1, WU Guo-Zhong2, CUI Zhi-Feng1, XU Xin-Sheng1   

  1. 1. Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, Anhui Province, P. R. China;
    2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China
  • Received:2010-11-01 Revised:2010-12-20 Published:2011-03-29
  • Contact: ZHU Guang-Lai, WU Guo-Zhong E-mail:wuguozhong@sinap.ac.cn; zhglai@mail.ahnu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20673137, 20903004), Science Foundation of the Education Committee of Anhui Province, China (KJ2010A145) and Scientific Research Starting Foundation for Teachers with Ph.D. in Anhui Normal University, China.

摘要:

利用纳秒级激光光解瞬态吸收光谱研究了联苯甲酰(BZ)在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF4])与乙腈(MeCN)混合体系中的光化学反应行为. 考察了探针分子BZ存在下[bmim][BF4]/MeCN比例对体系中化学反应动力学的影响. 实验发现: 在N2饱和条件下, BZ溶液经激光辐照后产生的激发三线态3BZ*遵循一级反应动力学规律衰减. 离子液体(IL)相对比例增加对3BZ*瞬态吸收峰的位置和强度没有产生明显影响. 但离子液体体积分数VIL的变化对[bmim][BF4]/MeCN混合溶剂中光诱导电子转移的影响却非常显著, 总体上电子转移产生的自由基的表观生成速率常数kgr随[bmim][BF4]的VIL增大而减小. 在[bmim]BF4]比例足够大的情况下, 3BZ*与三乙胺或四甲基对苯二胺之间的电子转移被抑制.

关键词: 室温离子液体, 1-丁基-3-甲基咪唑四氟硼酸盐, 联苯甲酰, 激光光解, 光诱导电子转移

Abstract:

Using benzil (BZ) as a probe molecule, the photochemical properties of the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and its binary mixed solutions with acetonitrile (MeCN) were investigated by nanosecond laser photolysis. We found that the decay of the triplet excited state of benzil (3BZ*) in a N2-saturated solution followed mono-exponential kinetics. Along with the increase in the volume fraction (VIL) of [bmim][BF4] in the mixed solvents, the absorption peak of 3BZ* did not change. However, the effect of different VIL values on the photoinduced electron transfer process in the mixture of [bmim][BF4]/MeCN was obvious. Moreover, the apparent rate constant (kgr) of the formed radical decreased obviously with an increase in VIL. When the ratio of [bmim][BF4] was sufficiently high, the electron transfer reaction between 3BZ* and triethylamine or N,N,N′,N′-tetramethyl-p-phenylenediamine was retarded.

Key words: Room temperature ionic liquid, 1-Butyl-3-methylimidazolium tetrafluoroborate, Benzil, Laser photolysis, Photoinduced electron transfer

MSC2000: 

  • O644