Dines Trevor J, Macgregor Louise D, Rochester Colin H
Department of Chemistry, University of Dundee, Dundee, DD1 4HN, United Kingdom.
J Colloid Interface Sci. 2002 Jan 15;245(2):221-9. doi: 10.1006/jcis.2001.8036.
IR spectra of N-methylpyrrole (NMP) have been measured following adsorption on, and subsequent desorption from, SiO(2), TiO(2), ZrO(2), SiO(2)-Al(2)O(3), H-mordenite, and sepiolite. Three modes of adsorption have been observed: (i) hydrogen bonding to surface hydroxyl groups, (ii) electron transfer at Lewis acidic surface sites, and (iii) proton transfer at Brønsted acidic surface sites. Protonation of NMP was detected only for adsorption on SiO(2)-Al(2)O(3) and H-mordenite, indicating the presence of Brønsted acidic sites with pK(a) values </=-2.90. The results establish that the adsorption of NMP can provide useful information regarding the nature of surface acidity on oxides which is complementary to that obtained from other probe molecules such as NH(3) and pyridine.
在N-甲基吡咯（NMP）吸附到SiO₂、TiO₂、ZrO₂、SiO₂ - Al₂O₃、H-丝光沸石和海泡石上并随后解吸后，测量了其红外光谱。观察到三种吸附模式：（i）与表面羟基形成氢键，（ii）在路易斯酸性表面位点发生电子转移，以及（iii）在布朗斯台德酸性表面位点发生质子转移。仅在吸附到SiO₂ - Al₂O₃和H-丝光沸石上时检测到NMP的质子化，表明存在pKₐ值≤ - 2.90的布朗斯台德酸性位点。结果表明，NMP的吸附可以提供有关氧化物表面酸性性质的有用信息，这与从其他探针分子（如NH₃和吡啶）获得的信息互补。
