Effect of substituent on the rate of reaction between 4Y‐ArNH2 (Y = H, F, Cl, CH3, OCH3, NH2, N(CH3)2, CF3, CN, NO2) with CH3OO• in the gas phase

Abstract

AbstractEffect of substituent (Y), including halogen (F and Cl), electron donating (ED) and electron withdrawing (EW) group on the thermoparameters and kinetic behavior of reactions between 4Y‐ArNH2 and CH3OO• was computationally studied using density functional theory (DFT) at M05‐2X/6‐311++G(d,p) method in combination with the transition state theory (TST) in Eyringpy program. Based on the three mechanisms of reaction between 4Y‐ArNH2 and CH3COO•, namely the hydrogen transfer (HAT/PCET), single electron transfer ‐ proton transfer (SET‐PT), and sequential proton loss electron transfer (SPLET), the effects on the thermoparameters involved in these mechanisms were investigated. ED group reduces the bond dissociation energy (BDE) and ionization energy (IE) then also increases the rate of hydrogen transfer reaction of 4Y‐ArNH2 and CH3OO•. Hydrogen atom transfer reaction of ArNH2 with CH3OO• at 298.15 K in the gas phase preferably takes place via PCET with the rate constant kPCET of 1.19×10‐19 cm3.molecule‐1.s‐1 is higher than that of kHAT of 2.19×10‐20 cm3.molecule‐1.s‐1. The rate constants of all 4Y‐ArNH2 + CH3OO• reactions were also reported and PCET mechanism is dominated with the branching ratio (Γ%) ranging from 73 % to 95 %.