Winter Leonhard, Bhuin Radha G, Maier Florian, Steinrück Hans-Peter
Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.
Chemistry. 2021 Dec 6;27(68):17059-17065. doi: 10.1002/chem.202102492. Epub 2021 Sep 29.
The interaction of molecules, especially hydrocarbons, at the gas/ionic liquid (IL) surface plays a crucial role in supported IL catalysis. The dynamics of this process is investigated by measuring the trapping probabilities of n-butane, iso-butane and 1-butene on a set of frozen 1-alkyl-3-methylimidazolium-based ILs [C C Im]X, where n=4, 8 and X =Cl , Br , [PF ] and [Tf N] . The decrease of the initial trapping probability with increasing surface temperature is used to determine the desorption energy of the hydrocarbons at the IL surfaces. It increases with increasing alkyl chain length n and decreasing anion size for the ILs studied. We attribute these effects to different degrees of alkyl chain surface enrichment, while interactions between the adsorbate and the anion do not play a significant role. The adsorption energy also depends on the adsorbing molecule: It decreases in the order n-butane>1-butene>iso-butane, which can be explained by different dispersion interactions.
分子间的相互作用，尤其是烃类在气/离子液体（IL）表面的相互作用，在负载型离子液体催化中起着至关重要的作用。通过测量正丁烷、异丁烷和1-丁烯在一组基于1-烷基-3-甲基咪唑鎓的冷冻离子液体[CnCIm]X（其中n = 4、8且X = Cl、Br、[PF6]和[Tf2N]）上的捕获概率，对该过程的动力学进行了研究。利用初始捕获概率随表面温度升高而降低的现象来确定烃类在离子液体表面的解吸能。在所研究的离子液体中，解吸能随着烷基链长度n的增加和阴离子尺寸的减小而增大。我们将这些影响归因于烷基链表面富集程度的不同，而吸附质与阴离子之间的相互作用并不起显著作用。吸附能也取决于吸附分子：其顺序为正丁烷>1-丁烯>异丁烷，这可以通过不同的色散相互作用来解释。
