Simulated kinetics of the atmospheric removal of aniline during daytime. (September 2020)

• Record Type: Journal Article
• Authors: Abdel-Rahman, Mohamed A.; Shibl, Mohamed F.; El-Demerdash, Safinaz H.; El-Nahas, Ahmed M.
• Is Part Of: Chemosphere. Volume 255(2020)
• Publication Date: 2020-09
• Subjects: Aniline -- Atmospheric oxidation -- OH radicals -- Ab initio -- DFT -- Kinetics; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127031
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Oxidations of aniline (AN) initiated by OH-radicals are simulated in the temperature range 200–400 K using DFT/M06-2X/6-311++G(2df, 2p) and ab initio ROCBS-QB3 levels. Chemical kinetics of such reactions were investigated based on several approaches including classical transition state theory (TST), conical variational transition state theory (CVT), and Rice-Ramsperger-Kassel-Marcus master equation (RRKM-ME) theories. Under atmospheric conditions, the reaction of OH radical with AN and the subsequent reactions with O2 molecules are investigated. The results indicate that the majority of O2 addition goes to the anti -directions with a branching ratio of 97.7% and produces the bicyclic peroxy radicals (BPRs) that can react with NO radical to form bicyclic alkoxy radicals (BARs). The latter compounds can be stabilized either by cyclization or via ring cleavage. Graphical abstract: Image 1 Highlights: The tropospheric consumption of aniline (AN) with the OH, O2 and NO radicals is discussed in details. The OH-addition at the ortho position of aniline (P2) prevails over the H-abstraction from its amino group. P2 adduct reacts reversibly with O2 yielding ∼2/3 cyclized product compared to irreversibly formed 2-aminophenol. A moderate temperature dependence and no pressure effects on the yield were found. In the subsequent reactions, nitrobenzene, 2-aminophenol and other products are formed.