Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China.
Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, 650500, China.
Environ Pollut. 2018 Jan;232:615-623. doi: 10.1016/j.envpol.2017.10.004. Epub 2017 Oct 9.
The catalytic hydrolysis of carbonyl sulfide (COS) and the effect of small clusters of HO and HSO have been studied by theoretical calculations. The addition of HSO could increase the enthalpy change (ΔH<0) and decrease relative energy of products (relative energy<0), resulting in hydrolysis reaction changed from an endothermic reaction to an exothermic reaction. Further, HSO decreases the energy barrier by 5.25 kcal/mol, and it enhances the catalytic hydrolysis through the hydrogen transfer effect. The (COS + HSO-HO) reaction has the lowest energy barrier of 29.97 kcal/mol. Although an excess addition of HO and HSO increases the energy barrier, decreases the catalytic hydrolysis, which is consistent with experimental observations. The order of the energy barriers for the three reactions from low to high are as follows: COS + HSO-HO < COS + HO + HSO-HO < COS + HO+(HSO). Kinetic simulations show that the addition of HSO can increase the reaction rate constants. Consequently, adding an appropriate amount of sulfuric acid promotes the catalytic hydrolysis of COS both kinetically and thermodynamically.
通过理论计算研究了羰基硫（COS）的催化水解以及 HO 和 HSO 小簇的影响。HSO 的加入可以增加焓变（ΔH<0）并降低产物的相对能量（relative energy<0），从而使水解反应从吸热反应变为放热反应。此外，HSO 通过氢键转移效应降低了 5.25 kcal/mol 的能量势垒，增强了催化水解作用。（COS+HSO-HO）反应具有最低的能量势垒 29.97 kcal/mol。尽管 HO 和 HSO 的过量加入会增加能量势垒，降低催化水解作用，但这与实验观察结果一致。三个反应的能量势垒从低到高的顺序如下：COS+HSO-HO<COS+HO+HSO-HO<COS+HO+(HSO)。动力学模拟表明，HSO 的加入可以增加反应速率常数。因此，适量添加硫酸可以在动力学和热力学上促进 COS 的催化水解。
