Molecular beam studies of HCl dissolution and dissociation in cold salty water
Molecular beam studies of HCl dissolution and dissociation in cold salty water
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DOI：
10.1039/c0cp02540b
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Nathanson, Gilbert M.
中科院分区：
文献类型：
--
作者：
Brastad, Susan M.;Nathanson, Gilbert M.
利用气液散射实验研究了208-218 K下HCl和DCl与12 mol% LiBr水溶液的碰撞和反应。这些类似于6 M的盐水溶液的蒸气压刚好低于0.01 Torr，需要特别考虑气体-蒸气碰撞的影响。我们发现，即使在入射能量为90 kJ mol（-1）的冲击HCl分子容易平衡的溶液的表面上。大约90%的热化HCl分子在冷的盐溶液中溶解和解离很长时间，而剩余的10%从表面完整地解吸。没有证据表明HCl在界面上快速转化为DCl，这与先前在292 K下DCl与盐甘油碰撞中观察到的明显亚微秒DCl -> HCl交换形成鲜明对比。这些结果表明，冷盐水有效地捕获碰撞HCl分子和抑制界面质子交换，最有可能是因为长的相互作用时间的HCl分子与冷表面接触，因为容易运输的H+和Cl-从界面区域到本体溶液。
Gas-liquid scattering experiments are used to explore collisions and reactions of HCl and DCl with 12 mol% LiBr solutions of H2O and D2O at 208-218 K. These similar to 6 M aqueous salt solutions have vapor pressures just below 0.01 Torr, requiring special consideration of the effects of gas-vapor collisions. We find that impinging HCl molecules readily equilibrate on the surface of the solution even at incident energies of 90 kJ mol(-1). Approximately 90% of the thermalized HCl molecules dissolve and dissociate for long times in the cold salty solution, while the remaining 10% desorb from the surface intact. There is no evidence for rapid, interfacial conversion of HCl into DCl, in striking contrast to previous observations of distinct submicrosecond DCl -> HCl exchange in collisions of DCl with salty glycerol at 292 K. These results indicate that cold salty water efficiently captures impinging HCl molecules and suppresses interfacial proton exchange, most likely because of the long interaction times of the HCl molecules in contact with the cold surface and because of facile transport of H+ and Cl- from the interfacial region into the bulk solution.