摘要
热流式微量量热计可以用来精确地直接测量吸附质分子在吸附剂表面的吸附热,表征吸附剂表面性质及其与吸附质分子的相互作用。但是,所得的吸附热只是一个统计平均结果,不能给出关于分子微观结构和运动的信息。为此,我们对热流式微分吸附热测定装置进行了改进,连接上红外光谱池,把直接表征分子微观运动的红外光谱与量热法结合起来,从而可对表面吸附现象和表面活性中心进行深入的研究。
The differential heats of adsorption (DHA) and IR spectra of alkenes on NaY and USY zeolites were measured at loom temperature with a SETARAM microcalorimcter and a PE-680 IR spectrophotometer respectively. The regularities of the DHA of alkenes on NaY were as follows:(1) DHA increased with the increasing of carbon atom in alkene molecule;(2) for alkenes with the same number of carbon atoms, DHA increased in the order of straight chain>iso->cyclic alkenes. Adsorption site Na+ in NaY zeolite could activate to a certain extent the jr-bond, but could not break down the π-bond. When alkenes adsorbed on USY zeolite, jr-bond was broken down to form carbonium ions. According to the results calculated from the DHA, the high activity of carbonium ions might be expected.
