Selected Reactive Sites Tuned by High Pressure: Oligomerization of Solid-State Cyanamide

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• 作者：Yuxiang Dai ; Kai Wang ; Hongsheng Yuan ; Xiao Meng ; Kun Luo ; Dongli Yu ; Jing Liu ; Xi Zhang ; Yuguo Ma ; Yongjun Tian ; Bo Zou
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：June 11, 2015
• 年：2015
• 卷：119
• 期：23
• 页码：12801-12807
• 全文大小：413K
• ISSN：1932-7455

文摘

We studied high-pressure reaction of solid cyanamide in a diamond anvil cell up to a pressure of 21.7 GPa. The results of in situ high-pressure Raman spectroscopy and angle-dispersive X-ray diffraction experiments indicated the occurrence of pressure-induced oligomerization in cyanamide over 13 GPa. The Raman, NMR, and UV absorption spectra of recovered samples confirmed that the chemical reaction was irreversible and that the high-pressure products contained C鈺怤 bonds. Subsequently, results of kinetic studies showed the relation between pressure and the reaction rate. Meanwhile dependence of activation volume with pressure indicated that the steric factors affected the reaction. Additionally, the increase in the amount of C鈥揅 bonds of recovered samples was attributed to the change of reactive sites of adjacent C鈮 groups. These results suggest that the application of pressure can tune both the reactive sites and the reaction rate to affect oligomerization and even other chemical reactions.