Experimental and Theoretical Study of Reaction of OH with 1,3-Butadiene

Abstract

The kinetics of the reaction of hydroxyl radical with 1,3-butadiene at 240-340 K and a total pressure of approximately 1 Torr has been studied using relative rate combined with the discharge flow and mass spectrometer technique. The reaction dynamics of the same reaction has also been investigated using ab initio molecular orbital theory. The rate constant for this reaction was found to be negatively dependent on temperature, with an Arrhenius expression of k1 = (1.58 +/- 0.07) x 10(-11) exp[(436 +/- 13)/T] cm3 molecule(-1) s(-1) (uncertainties taken as 2sigma), which was in good agreement with that reported by Atkinson et al. and Liu et al. at 299-424 K. Mass spectral evidences were found for the addition of OH to both the terminal and the internal carbons of 1,3-butadiene. Our computational results suggest that both addition of OH to 1,3-butadiene and the abstraction of hydrogen atom from 1,3-butadiene by the OH radical are exothermic processes and that the addition of OH to the terminal carbon of the 1,3-butadiene is predicted to have an activation energy of 0.7 kcal mol(-1), being the most energetically favored reaction pathway.

Experimental and Ab Initio Dynamical Investigations of the Kinetics and Intramolecular Energy Transfer Mechanisms for the OH + 1,3-Butadiene Reaction between 263 and 423 K at Low Pressure

“…The observed negative activation energy (E a /R ) -664 K) is in reasonable agreement with the value of E a /R ) -440 K obtained by Li et al 20 and the value of E a /R ) -470 K obtained by Atkinson et al 27 The negative temperature dependence observed for the OH + 1,3-butadiene reaction is consistent with a reaction mechanism that is dominated by OH addition to the double bond through the formation of a long-range complex 39 rather than by H-abstraction even at the low pressures and high temperatures of these experiments. Although the negative temperature dependence and absence of a pressure dependence could indicate a hydrogen-abstraction mechanism through a pre-reactive complex, similar to that observed in the OH + acetic acid reaction, 40 previous measurements of the products of the OH + 1,3-butadiene reaction and theoretical calculations of the potential energy surface suggest that H-abstraction is a minor product channel.…”

“…[17][18][19][20] The reaction of 1,3-butadiene with the hydroxyl radical is considered to be the dominant chemical loss process during the daytime, with lifetimes of 1 and 4.5 h for OH concentrations of approximately 2 × 10 6 and 8 × 10 5 molecule cm -3 . 20,21 A generic mechanism for the OHinitiated oxidation of 1,3-butadiene is shown below: Under atmospheric conditions, the butadiene-OH adducts react with O 2 to form peroxy radicals that subsequently react in the presence of NO to form alkoxy radicals and NO 2 . 17,22,23 The major identifiable products observed from the OH-radicalinitiated oxidation of 1,3-butadiene in the presence of NO are acrolein, 19,[23][24][25][26] furan, 19,22,23,26 formaldehyde, 17,25,26 4-hydroxy-2-butenal, 26 and organic nitrates.…”

“…Atkinson et al 27 measured a rate constant of (6.85 ( 0.69) × 10 -11 cm 3 molecule -1 s -1 at 299 K and derived an Arrhenius expression of k 1 II (T) ) 1.45 × 10 -11 exp[(930 ( 300)/RT] cm 3 molecule -1 s -1 at 50 Torr in argon between 299 and 424 K using flash photolysis coupled with resonance fluorescence detection of OH radicals. Liu et al 28 measured the rate constant for the OH + 1,3-butadiene reaction in 760 Torr of argon over the temperature range of 313-1203 K using pulse radiolysis coupled with resonance absorption detection of OH radicals, obtaining an Arrhenius expression of k 1 II (T) ) (1.4 ( 0.1) × 10 -11 exp [(440 ( 40)/T] cm 3 molecule -1 s -1 between 313 and 623 K and a rate constant of (6.1 ( 0.6) × 10 -11 cm 3 molecule -1 s -1 at 313 K. Llyod et al, 29 using a relative rate method in an environmental chamber, found the rate constant to be (7.45 ( 1.45) × 10 -11 cm 3 molecule -1 s -1 at 305 K. Li et al 20 have recently reported a rate constant of (6.93 ( 0.48) × 10 -11 cm 3 molecule -1 s -1 at 1 Torr and 298 K using a relative rate discharge flow technique coupled with a mass spectrometer. They also obtained an Arrhenius expression of k 1 II (T) ) (1.58 ( 0.07) × 10 -11 exp [(436 ( 13)/T] cm 3 molecule -1 s -1 at 1 Torr between 240 and 340 K, in good agreement with the previous measurements at 760 Torr, suggesting that the rate constant for the OH + 1,3-butadiene reaction is at its highpressure limit at 1 Torr.…”

On the identity and reactivity patterns of the “second oxidant” of the T252A mutant of cytochrome P450cam in the oxidation of 5-methylenenylcamphor

“…5 reveals that the attack of OH Å on the double bond of the substrate does not actually require a barrier. This is understandable since experimental and computational data for OH attack on double bonds reveal reactions that are virtually diffusion controlled [53][54][55]. Since I O-O requires a small barrier to generate a meso-hydroxylated product (1.7 kcal/mol), P meso , the OH Å attack on the C@C bond of 1 will compete favorably with this degradation process.…”

Theoretical study for ozonolysis of 1,3-butadiene

“…It is a product of industrial processes [28,29], tobacco smoke [30], and motor vehicle exhaust [31]. It can react in the atmosphere with OH [32], Cl [33] and O 3 [34][35][36] forming a series of products. In 1999, Kramp et al [36] performed experimental studies on the reaction of ozone with 1,3-butadiene at room temperature and atmosphere pressure.…”