T- And Ph -Dependent Kinetics Of The Reactions Of "Oh(Aco With Glutaric And Adipic Acid For Atmospheric Aqueous -Phase Chemistry

Glutaric acid and adipic acid are dicarboxylic acids this(DCsA (DCAs) are m nlY found in atmospheric aerosols and cloud droplets. Within study, theemperature- m and PH-dependent rate constants of aqueous -Phase OH radical reactions of these two DCAs were determined through the competition kinetics method. The following Arrhenius expressions derived for the temperature dependency of theOH radical reaction withglutar wereicacid :k(T, H2A) = (3.9 + 0.1) x 101 x exp[(-1270 200 K)/T], k(7''HA) = (2.3 0.1) x 1011 x exp[(-1660 190 K)/T], k(T, A2-) = (1.4 0.1) x 1011170x exp[(-1400 K)/T]. Similarly, for adipic acid: k(T, H2A) (7 [(-1210 1701()/T], k(1'' HA) = (9.5 0.3) x 10 10/Tx e-'41][.(5-0.20.02) (010xe P2010I(){T],k('T, A2-) (8.7 0.2) X 1010 x e,q,[(-1100 170K)(unitsm in of L 1-1 s-). Density functional theory(DFT) calculations were performed to calculate the energy barrier of the H atom abstraction. The calculation results show that the energy barriers thatatthe Cp-atoms of the two DCAs are much lower than those at the Ca-atoms, indicatingthe H atom abstractions predominantly occur at the Cfi-atoms. The increased.0H rate constant in the case of the deprotonated form can be explained by the reduction of energy barrier, which is predominately caused by the variation of the inductive effect of the carboxyl group. As an important sink in the atmosphere, the degradation of glutaric acid and adipic acid by -OH under atmospheric conditions can be accurately described by the.irrlienius expressions obtained.