Bhuin Radha G, Winter Leonhard, Lexow Matthias, Maier Florian, Steinrück Hans-Peter
Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.
Angew Chem Int Ed Engl. 2020 Aug 17;59(34):14429-14433. doi: 10.1002/anie.202005991. Epub 2020 Jul 1.
The impact of a reactant from the gas phase on the surface of a liquid and its transfer through this gas/liquid interface are crucial for various concepts applying ionic liquids (ILs) in catalysis. We investigated the first step of the adsorption dynamics of n-butane on a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ILs ([C C Im][Tf N]; n=1, 2, 3, 8). Using a supersonic molecular beam in ultra-high vacuum, the trapping of n-butane on the frozen ILs was determined as a function of surface temperature, between 90 and 125 K. On the C - and C -ILs, n-butane adsorbs at 90 K with an initial trapping probability of ≈0.89. The adsorption energy increases with increasing length of the IL alkyl chain, whereas the ionic headgroups seem to interact only weakly with n-butane. The absence of adsorption on the C - and C -ILs is attributed to a too short residence time on the IL surface to form nuclei for condensation even at 90 K.
气相反应物对液体表面的影响及其通过气/液界面的转移对于各种在催化中应用离子液体（ILs）的概念至关重要。我们研究了正丁烷在一系列1-烷基-3-甲基咪唑鎓双（三氟甲磺酰）亚胺离子液体（[CnC1Im][Tf2N]；n = 1、2、3、8）上吸附动力学的第一步。在超高真空中使用超音速分子束，确定了正丁烷在90至125 K的表面温度范围内在冷冻离子液体上的捕获情况。在C1-和C2-离子液体上，正丁烷在90 K时吸附，初始捕获概率约为0.89。吸附能量随着离子液体烷基链长度的增加而增加，而离子头基似乎与正丁烷的相互作用较弱。在C8-和C12-离子液体上没有吸附，这归因于即使在90 K时在离子液体表面的停留时间太短，无法形成凝聚核。
