The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechani...The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechanism of kaolinite/formamide compound. The proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinte are in the range of δ-1.3--0.9 and δ 2.4-3.0 respectively. After formamide intercalation three proton peaks were detected. The proton peak of the inner surface hydrox-yls of the intercalation compound shifts to high-field with δ2.3-2.7, which is assigned to the formation of the hydrogen bond between the inner surface hydroxyl and formamide carbonyl group. Whereas, the proton peak of the inner hydroxyl shifts to δ-0.3 toward low-field, that is attributed to van der Waal’s effect between the inner hydroxyl proton and the amino group proton of the formamide which may be keyed into the ditrigonal hole of the kaolinite. The third peak, additional proton peak, is in the展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 40072014)by the Foundation of State Key Laboratory for Physical Chemistry of Solid Surfaces in Xiamen University (Grant No. 9911).
文摘The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechanism of kaolinite/formamide compound. The proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinte are in the range of δ-1.3--0.9 and δ 2.4-3.0 respectively. After formamide intercalation three proton peaks were detected. The proton peak of the inner surface hydrox-yls of the intercalation compound shifts to high-field with δ2.3-2.7, which is assigned to the formation of the hydrogen bond between the inner surface hydroxyl and formamide carbonyl group. Whereas, the proton peak of the inner hydroxyl shifts to δ-0.3 toward low-field, that is attributed to van der Waal’s effect between the inner hydroxyl proton and the amino group proton of the formamide which may be keyed into the ditrigonal hole of the kaolinite. The third peak, additional proton peak, is in the
