A kinetic investigation of unimolecular reactions involving trace metals at post-combustion flue gas conditions

作者：Wilcox Jennifer^*

来源：Environmental Chemistry, 2011, 8(2): 207-212.

DOI：10.1071/EN11001

Ab-initio methods were carried out to calculate forward and reverse rate constant data for the following reactions: Hg+Cl(2)<-> HgCl(2), HgCl+Cl <-> HgCl(2), Hg+O <-> HgO, and Se+H(2)<-> SeH(2). Theoretical predictions of bond distances, vibrational frequencies and enthalpies of reaction are compared to available experimental data to determine the level of theory most appropriate for predicting kinetic parameters. The pseudopotentials ECP60MDF and RECP60VDZ were used for mercury in combination with B3LYP or QCISD(T) methods whereas the complete 6-311++G(3df,3pd) Pople basis set with the CCSD(T) method was used for selenium. Potential energy curves for each reaction were constructed and a variational approach along with RRKM theory was used to predict rate constants from 298 to 2000 K. Reactions HgCl+Cl <-> HgCl(2) and Hg+O <-> HgO were found to have a strong negative temperature dependence, whereas the insertion reactions Hg+Cl(2)<-> HgCl(2) and Se+H(2)<-> SeH(2) were found to proceed very slowly with large pre-exponential factors.

• 出版日期2011