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atmosphere Article

Rate Constants for the Reaction of OH Radicals with Hydrocarbons in a Smog Chamber at Low Atmospheric Temperatures Lei Han *,‡

ID

, Frank Siekmann and Cornelius Zetzsch *,‡

Atmospheric Chemistry Research Laboratory, University of Bayreuth, 95447 Bayreuth, Germany; [email protected] * Correspondence: [email protected] (L.H.); [email protected] (C.Z.) ‡ Current address: Department of Multiphase Chemistry, Max Planck Institute for Chemistry, 55128 Mainz, Germany. Received: 18 July 2018; Accepted: 14 August 2018; Published: 18 August 2018

Abstract: The photochemical reaction of OH radicals with the 17 hydrocarbons n-butane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, cyclooctane, 2,2-dimethylbutane, 2,2-dimethylpentane, 2,2-dimethylhexane, 2,2,4-trimethylpentane, 2,2,3,3-tetramethylbutane, benzene, toluene, ethylbenzene, p-xylene, and o-xylene was investigated at 288 and 248 K in a temperature controlled smog chamber. The rate constants were determined from relative rate calculations with toluene and n-pentane as reference compounds, respectively. The results from this work at 288 K show good agreement with previous literature data for the straight-chain hydrocarbons, as well as for cyclooctane, 2,2-dimethylbutane, 2,2,4-trimethylpentane, 2,2,3,3-tetramethylbutane, benzene, and toluene, indicating a convenient method to study the reaction of OH radicals with many hydrocarbons simultaneously. The data at 248 K (k in units of 10−12 cm3 s−1 ) for 2,2-dimethylpentane (2.97 ± 0.08), 2,2-dimethylhexane (4.30 ± 0.12), 2,2,4-trimethylpentane (3.20 ± 0.11), and ethylbenzene (7.51 ± 0.53) extend the available data range of experiments. Results from this work are useful to evaluate the atmospheric lifetime of the hydrocarbons and are essential for modeling the photochemical reactions of hydrocarbons in the real troposphere. Keywords: OH radicals; smog chamber; rate constant; hydrocarbons; low temperatures

1. Introduction Great quantities of volatile organic compounds (VOCs) are emitted into the atmosphere from both anthropogenic and natural sources. Their atmospheric concentrations are influenced by chemical reactions in the atmosphere, where the main removal pathway for alkanes and alkylated aromatics occurs through chemical oxidation by OH radicals [1,2]. In the past few decades, many studies have been focused on the atmospheric reaction of OH radicals with alkanes and aromatics [3–13] since these kinetic data are important to estimate the lifetime of the VOCs in the atmosphere. Smog chamber studies have started in the 1950s after the London smog episode [14]. At the beginning, they were designed mainly to study the gas-phase reactions with ozone and the chemistry of NOx in the troposphere and the formation of aerosol from the gaseous pollutants [15–17]. Later research concentrated on the reactions of VOCs with OH radicals and their role in ozone formation and photochemical smog [18–20]. Despite intensive research on gas-phase kinetics during the last decades, comparatively little is known about the reactivity of OH radicals with VOCs below room temperature, especially for larger molecules [4,21–23]. Based on the standard atmospheric values specified by the International Civil Aviation Organization (ICAO), the sea level temperature is 288 K [24] and

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Atmosphere 2018, 9, 320

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drops by approximately 6.5 K per kilometer of altitude up to the tropopause [14]. However, very few hydrocarbons have been investigated at temperatures below 290 K, which are representative of the troposphere. The understanding of kinetics at low temperature is of great importance to understand the real atmospheric degradation of organic compounds. There has been theoretical research about the reaction of OH with hydrocarbons [6,25,26], giving guidance to understand the kinetics at low temperatures. Subsequent to an extensive review on the reactions of alkanes and cycloalkanes with OH by Atkinson [27], there are only a few studies below room temperature. DeMore and Bayes [4] measured the relative rate constant of n-butane, n-pentane, and other cyclic hydrocarbon at temperatures down to 233 K. Harris and Kerr [21] developed a flow reactor system to study the relative rate constant of OH radicals with n-pentane, 2,2-dimethylbutane, and several other hydrocarbons, over a temperature range of 243–328 K. Talukdar et al. [22] measured the rate constant of n-butane and n-pentane over the temperature range of 212–380 K by using the pulsed photolysislaser induced fluorescence (PP-LIF) technique. Li et al. [28] studied n-octane, n-nonane, and n-decane relative to 1,4-dioxane at temperatures down to 240 K and Crawford et al. [29] studied the reactions of OH radicals with n-hexane and n-heptane at 240–340 K. Wilson et al. [30] studied the reactions of several alkanes and cycloalkanes with hydroxyl radicals in a photochemical glass reactor with GC/MS detection at temperatures down to 241 K. Cyclooctane and other alkanes were studied by Sprengnether et al. [31] at temperatures down to 237 K in a high-pressure flow reactor with LIF detection, and by Singh et al. [32] in a discharge flow reactor at temperatures down to 240 K. Tully et al. [23] studied the absolute rate constant of OH radicals with benzene and toluene at temperature down to 213 K, and Witte et al. [33] obtained similar results for benzene at 239–352 K. Semadeni et al. also studied the OH reactivity of benzene by using toluene as a reference compound at 274–363 K. Mehta et al. [34] measured the rate constant of OH with o- and p-xylene at 240–340 K, by using the relative rate/discharge flow/mass spectrometry (RR/DF/MS) technique. Alarcón et al. [35] used the flash photolysis resonance fluorescence technique (FPRF) to study the reaction of OH radicals with methylated benzenes including p-xylene, delivering an Arrhenius expression of the absolute rate constants between 300 and 350 K. A table with information on the various research conducted at low temperatures is available in Supporting Information (SI, Table S1). In this work, we have investigated the gas phase reaction of OH with several alkanes and aromatic compounds at 288 K (sea level temperature) and 248 K (in the free troposphere this temperature corresponds to a height of approximately 5–8 km, depending on latitude and season [36]). Using n-pentane [27] and toluene [37] as reference compounds, the rate constants for the reactions of OH radicals with the 17 compounds have been obtained at 248 and 288 K. These two compounds are chosen as reference compounds, because their temperature-dependent parameters are well investigated between 220 to 350 K. Those data deliver chemical kinetic information about the temperature range below room temperature, and therefore are supplementary to the existing Arrhenius expression. 2. Experiments 2.1. Description of the Simulation Chamber The simulation chamber is located at the Atmospheric Chemistry Research Laboratory of the University of Bayreuth in a temperature controllable room, where the temperature could be set from 298 K to 248 K with the aid of an inside cooling system in the room and monitored by a thermistor Epcos NTC 50 K, calibrated against a platinum resistance thermometer (Keithley 195A with probe 8693) from −40 ◦ C to +30 ◦ C. The chamber consists of four cylinder sections made of glass (Duran, Schott, inner diameter 1 m, total height 4 m), yielding a volume of 3.2 m3 . Sixteen fluorescent lamps (Osram Eversun, 80 W each, kept at 300 K by an air thermostat) were employed as light sources, irradiating the chamber from the bottom through Teflon film (FEP 200A). The emission spectrum of the lamps has a Gaussian shape with a maximum at 350 nm, it starts at 300 nm and extends beyond 450 nm, containing the emission lines of mercury. The inherent heating effects on the bottom caused by the lamps led to a


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vertical temperature gradient, to enhancing thefurther mixing efficiency. Sensors in the middle and upper the middle of the chamber accelerate mixing. The temperature regulation leadspart to of the chamber measured the temperature and a ventilator was installed in the middle of the chamber variations of ±1 K in the refrigerated laboratory. A schematic diagram of the simulation chamber is to accelerate mixing. The temperature regulation leads to variations of ±1 K in the refrigerated shown belowfurther (Figure 1). laboratory. A schematic diagram of the simulation chamber is shown below (Figure 1). 1m FEP Teflon film 0.4 m

OH precursor and hydrocarbons

Temperature sensors

0.5 m

Gas-phase analysis by GC

Bypass air

Ventilator

1.2 m

FEP Teflon film

16 Fluorescent lamps (Osram Eversun)

Figure 1. Schematic of the low temperature smog chamber facility. The hydrocarbons were injected into the smog chamber via syringes from two stock mixtures (see text), the gas-phase compounds sampledthrough throughaastainless stainlesssteel steel capillary and analyzed GC-FID sample enrichment were sampled capillary and analyzed by by GC-FID withwith sample enrichment (see (see below). Purified air was supplied viaaid theof aid of a bypass. below). Purified air was supplied via the a bypass.

2.2. 2.2. Instrumentation Instrumentation and and Chemical Chemical Materials Materials The byby a The concentration concentration of of the the hydrocarbons hydrocarbons(starting (startingwith withapprox. approx.2020ppb ppbeach) each)was wasmonitored monitored gas chromatograph (GC) with a flame ionization detector (FID). It uses an automated cryogenic a gas chromatograph (GC) with a flame ionization detector (FID). It uses an automated cryogenic sample enrichmentsystem systemwith withliquid liquidnitrogen nitrogen [10], that been modified by substituting the 6sample enrichment [10], that hashas been modified by substituting the 6-port port valve by two magnetic valves (for detailed information see Figure S1 in Supporting Information, valve by two magnetic valves (for detailed information see Figure S1 in Supporting Information, SI). SI).gas A sample gas sample of 30 mL wasevery taken30every The GC (Sichromat II, Munich, Siemens,Germany) Munich, A of 30 mL was taken min. 30 Themin. GC (Sichromat II, Siemens, Germany) is with equipped with a column capillary(Al2O3-PLOT, column (Al2O3-PLOT, Chrompack/Agilent) 50 mand length is equipped a capillary Chrompack/Agilent) with 50 with m length an ◦ and an inner diameter of 0.32 mm, using N 2 as carrier gas at a column temperature of 190 °C and a inner diameter of 0.32 mm, using N2 as carrier gas at a column temperature of 190 C and a FID ◦ FID temperature 270In°C. In order to the inject 17 hydrocarbons n-butane, n-pentane, n-hexane, ntemperature of 270of C. order to inject 17 the hydrocarbons n-butane, n-pentane, n-hexane, n-heptane, heptane, n-octane, n-nonane, cyclooctane, 2,2-dimethylbutane, 2,2-dimethylpentane, 2,2n-octane, n-nonane, cyclooctane, 2,2-dimethylbutane, 2,2-dimethylpentane, 2,2-dimethylhexane, dimethylhexane, 2,2,4-trimethylpentane, 2,2,3,3-tetramethylbutane, benzene, toluene, ethylbenzene, 2,2,4-trimethylpentane, 2,2,3,3-tetramethylbutane, benzene, toluene, ethylbenzene, p-xylene, o-xylene, p-xylene, o-xylene, and (inert n-perfluorohexane (inert standard) simultaneously thecontainers chamber,were two and n-perfluorohexane standard) simultaneously into the chamber, twointo glass glass containers were employed as a storage device for preparing stock mixtures, which minimized employed as a storage device for preparing stock mixtures, which minimized the operating deviation the operating deviation during theSection injection SI was Section S1). Methyl [38] nitrite selfduring the injection process (see SI S1).process Methyl(see nitrite self-synthesized andwas used as synthesized [38] and used as a photochemical precursor of the OH radicals. Two gas containers (1.3 a photochemical precursor of the OH radicals. Two gas containers (1.3 L of each) were connected in L of each) were connected in series to approximate a constant concentration series to approximate a constant concentration of OH (see Figure S2 in SI). of OH (see Figure S2 in SI).


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2.3. Calculation of the Reaction Rate Constant of OH with Hydrocarbons In this study, the relative rate method was used to calculate the rate constant of the OH radical with the hydrocarbons. Assuming that the decrease of hydrocarbons in the chamber is caused by the reaction with OH radicals and by the dilution from the gas sampling process, one gets the following simple reaction scheme: kHC OH

HC + OH → products

(1)

k

dil HC → loss

(2)

d[HC] = −kHC OH [OH]· dt − k dil · dt [HC]

(3)

to be described by the differential equation

where [HC] and [OH] represent the concentration of hydrocarbon and OH radicals at time t, respectively, kHC OH , is reaction rate constant of target hydrocarbon with OH and kdil includes other changes that cause the decrease of the hydrocarbons (e.g., dilution, wall adsorption). By using n-perfluorohexane (PFH) as an internal standard, we corrected the hydrocarbon data for the dilution of the chamber contents by the gas consumption of the gas analyzers for ozone and NOx , eliminating the second term from Equation (3). Integration then leads to the simple equation Z HC0 0 HC ln = k [OH]dt OH HC0 t

(4)

where [HC’]t and [HC’]0 are the dilution-corrected concentrations of the target hydrocarbon at time t and time zero, respectively, according to [HC’] = [HC] [PFH]0 /[PFH]. The presence of several hydrocarbons in the same experiment opens the opportunity to select one of those as a reference compound (REF), in order to eliminate the time integral of OH and to obtain REF relative rate constants, kHC OH /k OH , from the equation: ln

HC0

HC0

t 0

=

kHC OH kREF OH

ln

REF0

REF0

t

(5)

0

where [REF’]t and [REF’]0 are the (by PFH, see above) dilution-corrected concentrations of the reference compound (n-pentane and toluene in this study) at time t and time zero, respectively. From the plots of ln([HC’]t /[HC’]0 ) versus ln([REF’]t /[REF’]0 ), straight lines are expected with zero intercept, and the slopes represent the relative rate constants. Based on the known reaction rate constant of the reference HC compound, kREF OH , the OH reaction rate constant of the target hydrocarbon k OH can be calculated. 3. Results In relative rate constant measurements, the FID peak area represents the concentration of each sampling point. Figure 2 shows the hydrocarbon concentrations (corrected for dilution) from one single experiment at 288 K. Following Equation (5), one can get a straight line from a plot of ln([HC’]0 /[HC’]t ) of the hydrocarbons versus ln([REF’]0 /[REF’]t ) for the reference compound in most cases. Three experiments were carried out at 288 K, and two experiments were performed at 248 K. The rate constants were calculated from the experimental data from all runs at each temperature (Figure 3 for straight-chain hydrocarbons, with toluene as reference compound). Table 1 summarizes results obtained for the reaction from OH with the hydrocarbons at 288 K and the results at 248 K are summarized in the supporting material (Table S2), using n-pentane and toluene as reference compounds, respectively.


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5 of 16 5 of 16 n-butane n-pentane 2,2-dimethylbutane n-butane n-hexane n-pentane 2,2-dimethylpentane 2,2-dimethylbutane n-heptane n-hexane benzene 2,2-dimethylpentane 2,2,4-trimetylpentane n-heptane 2,2-dimethylhexane benzene 2,2,3,3-tetramethylbutane 2,2,4-trimetylpentane n-octane 2,2-dimethylhexane cyclooctane 2,2,3,3-tetramethylbutane toluene n-octane

1

FID-Area (normalized) FID-Area (normalized)

1

0.1 0.1

n-nonane cyclooctane ethylbenzene toluene

p-xylene n-nonane o-xylene ethylbenzene

0.01

p-xylene o-xylene

0.01

0

2 0

4

t/h

2

6

4

6

t/h Figure 2. Decrease of hydrocarbon concentrations (normalized by n-perfluorohexane) during a smog chamber run by reaction with OH at 288 K (corresponding information at 248 K is during displayed in the Figure 2. Decrease of hydrocarbon concentrations (normalized by n-perfluorohexane) n-perfluorohexane) smog Figure 2. Decrease of hydrocarbon concentrations (normalized by during aa smog SI). chamberrun runby byreaction reactionwith withOH OHatat 288 (corresponding information at 248 is displayed in SI). the chamber 288 KK (corresponding information at 248 K isKdisplayed in the SI). 6 n-Butane n-Pentane n-Butane n-Hexane n-Pentane n-Heptane n-Hexane n-Octane n-Heptane n-Nonane n-Octane Cyclooctane n-Nonane Cyclooctane

6

5 5

ln (c0/ct ) ln (c0/ct )

4 4

(a) (a)

n-Butane n-Pentane n-Butane n-Hexane n-Pentane n-Heptane n-Hexane n-Octane n-Heptane n-Nonane n-Octane Cyclooctane n-Nonane Cyclooctane

(b) (b)

3 3

2 2

1 1

0

00

0

1

1

2 2

ln (c0/ct ) Toluene ln (c0/ct ) Toluene

3 3

0.0 0.0

0.5 0.5

1.0 1.0

ln (c /c ) Toluene

1.5

1.5

2.0

2.0

ln (c0/c0t ) tToluene

Figure 3.3.Plot ofof ln(c /c0t/c ) of alkanes and cyclooctane versus toluene (reference substance). Figure Plot t) straight-chain of straight-chain alkanes and cyclooctane versus toluene (reference 0ln(c Figure3. Plot of ln(c 0/ct) of straight-chain alkanes and cyclooctane versus toluene (reference (a) Data points of three experimental runs at 288 K; (b) Data points of two experimental runs at 248 K. substance). (a) Data points of three experimental runs at 288 K; (b) Data points of two experimental substance). (a) Data points of three experimental runs at 288 K; (b) Data points of two experimental The curvature of the data and the non-zero intercept for n-nonane at 248 K indicate experimental runs the non-zero non-zerointercept interceptfor forn-nonane n-nonane 248 K indicate runsatat248 248K.K.The Thecurvature curvature of of the the data data and and the at at 248 K indicate limitations of limitations adsorption in the sampling capillary of the gas chromatograph. The symbols 5, # andThe The experimental the sampling sampling capillaryofofthe thegas gaschromatograph. chromatograph. experimental limitations of of adsorption adsorption in in the capillary distinguish data points from different experimental runs, plots of branched-chain alkanes and aromatic symbols from diﬀerent diﬀerentexperimental experimentalruns, runs,plots plots branchedsymbols▽, ▽,○○and and□□distinguish distinguish data data points from of of branchedhydrocarbons are displayed in the SI. chain alkanes displayedin inthe theSI. SI. chain alkanesand andaromatic aromatichydrocarbons hydrocarbons are displayed

At a temperature ofconstants 248 K, the decrease byradicals exposure tohydrocarbons OH appeared to288 be delayed for Table1.1.Rate Rate constants forinitial the reaction reaction of with at at 288 K. K. Table for the of OH OH radicals with hydrocarbons compounds with lower vapor pressures, such as n-nonane (Figure 3b) and p-xylene and o-xylene (SI, −12−12 3 s3−1 −1 Rate Constant, (k(kOH cm Rate Constant, OH±±2σ)/10 2σ)/10 cm Figure S5b). This is possibly due to adsorption in the sampling capillary of the gass chromatograph Compound Compound a b b Average a Pentane Toluene as Reference as Reference Toluene as Reference Pentane as Reference Average (stainless steel, 1/16 inch, 5 m long) that was not heated during the experiments. n-Butane 2.28 ± 0.02 2.05 ± 0.03 2.16 ± 0.04 n-Butane 2.28 ± 0.02 2.05 ± 0.03 2.16 ± 0.04 b n-Pentane 3.84 ± 0.04 3.62 3.73 ± 0.04 b n-Pentane 3.84 ± 0.04 3.62 3.73 ± 0.04 n-Hexane 5.41 ±± 0.03 5.25 5.33 ± 0.06 n-Hexane 5.41 0.03 5.25± ±0.05 0.05 5.33 ± 0.06 n-Heptane 7.10 ± 0.04 6.79 ± 0.06 6.94 ± 0.07 n-Heptane 7.10 ± 0.04 6.79 ± 0.06 6.94 ± 0.07 n-Octane 9.07 ± 0.08 8.62 ± 0.13 8.84 ± 0.15 n-Octane 9.07 ± 0.08 8.62 ± 0.13 8.84 ± 0.15 n-Nonane 12.0 ± 0.4 11.5 ± 0.5 11.8 ± 0.6

n-Nonane

12.0 ± 0.4

11.5 ± 0.5

11.8 ± 0.6


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Table 1. Rate constants for the reaction of OH radicals with hydrocarbons at 288 K.

Compound n-Butane n-Pentane n-Hexane n-Heptane n-Octane n-Nonane Cyclooctane 2,2-Dimethylbutane 2,2-Dimethylpentane 2,2-Dimethylhexane 2,2,4-Trimethylpentane 2,2,3,3-Tetramethylbutane Benzene Toluene Ethylbenzene p-Xylene o-Xylene

Rate Constant, (kOH ± 2σ)/10−12 cm3 s−1 Toluene as Reference a

Pentane as Reference b

Average

2.28 ± 0.02 3.84 ± 0.04 5.41 ± 0.03 7.10 ± 0.04 9.07 ± 0.08 12.0 ± 0.4 16.1 ± 0.4 2.11 ± 0.02 3.21 ± 0.03 4.74 ± 0.03 3.48 ± 0.03 1.01 ± 0.02 1.11 ± 0.02 5.86 a 6.95 ± 0.08 16.0 ± 0.9 15.6 ± 0.7

2.05 ± 0.03 3.62 b 5.25 ± 0.05 6.79 ± 0.06 8.62 ± 0.13 11.5 ± 0.5 15.8 ± 0.5 2.04 ± 0.02 3.14 ± 0.04 4.57 ± 0.04 3.35 ± 0.03 0.98 ± 0.01 1.04 ± 0.01 5.52 ± 0.06 6.72 ± 0.15 15.4 ± 1.1 15.2 ± 0.9

2.16 ± 0.04 3.73 ± 0.04 5.33 ± 0.06 6.94 ± 0.07 8.84 ± 0.15 11.8 ± 0.6 15.9 ± 0.6 2.07 ± 0.03 3.18 ± 0.05 4.66 ± 0.05 3.41 ± 0.04 1.00 ± 0.02 1.08± 0.02 5.69 ± 0.06 6.83 ± 0.17 15.7 ± 1.4 15.4 ± 1.1

k (toluene) = 1.8 × 10−12 e340/T cm3 molecule−1 s−1 (210–350 K) and 5.86 × 10−12 cm3 molecule−1 s−1 at 288 K [37]; b k (n-pentane) = 2.52 × 10−17 T2 e158/T cm3 molecule−1 s−1 (220–760 K) and 3.62 × 10−12 T2 e361/T at 288 K [27]. a

4. Discussion The rate constants for the reactions of the hydrocarbons with OH radicals derived from this study are plotted together with literature data in Arrhenius diagrams for the n-alkanes and cyclooctane (Figure 4), branched-chain alkanes (Figure 5), and aromatic hydrocarbons (Figure 6). In order to compare to previous evaluations, the regression lines from the Arrhenius expressions for each hydrocarbon are displayed in the figures. Detailed explanations and illustrations for the alkanes and cycloalkanes can be found in the review article by Atkinson [27]. Our results demonstrate that the rate constants obtained in the present study generally agree well with the literature data, which prove that the experimental method is reliable. Moreover, the experimental results complement existing gas-phase kinetic data for hydrocarbons in the following points: (1) For n-alkanes, results from this work follow the existing Arrhenius expressions quite well (Figure 4). The rate constants decrease as the temperature decreases, showing a positive correlation of temperature with the reactivity. For n-hexane, Atkinson [27] has recommended two Arrhenius 1 k (n-hexane) = 2.29 × 10−11 e−(442 ± 52)/T cm3 molecule−1 s −1 , 2 k (n-hexane) = 2.54 expressions: − 14 − (112 ± 28)/T 3 − 1 − 1 × 10 Te cm molecule s . The rate constants obtained from this work at 288 K and 248 K confirm that a third type of Arrhenius expression (k = AT2 e−B/T ) does also fit to the existing data 3 k = 1.82 × 10−17 T 2 e361/T cm3 molecule−1 s−1 [27]). More experimental data are needed (especially ( at high temperatures) to determine a more appropriate temperature dependence relationship from the existing Arrhenius expressions. Data reported by Crawford et al. [29] for n-hexane are away from 3 and in case of n-heptane, their data are also lower than the recommended Arrhenius expression expression, indicating a systematic deviation. When using only n-hexane as reference compound, our result at 248K for n-heptane agrees to the results of Crawford et al. and Wilson et al. (see SI, Figure S6). In addition, we compared the different results when using n-butane, n-pentane, and n-hexane as reference compounds respectively. The calculated rate constant decrease with increasing CH2 chains: 7.00 ± 0.19, 6.32 ± 0.14 and 5.47 ± 0.01 (in unit × 10−12 cm3 molecule−1 s−1 , result with n-hexane is plotted in SI), respectively (rate constant of reference compounds refers to Atkinson [27]). Since Crawford et al. (n-octane and n-nonane) and Wilson et al. (di- and tri-methylpentanes and n-octane) used higher hydrocarbon molecules as reference compounds, their results of rate constants for n-heptane were expected to be lower than ours. Based on the discussions of this work, there are


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several possible Arrhenius expressions for n-hexane, therefore, we choose n-pentane as our reference compound, for9,which a more comprehensive understanding of temperature-dependence is available. Atmosphere 2018, x FOR PEER REVIEW 7 of 16 This explains why our data are higher than the existing results. However, more experimental research, with absolute is needed toisclarify the reaction ratereaction constantrate of OH radicals especially withmeasurements absolute measurements needed toreal clarify the real constant of with OH n-heptane at low temperature. results forOur n-octane are consistent withconsistent previous radicals with n-heptane at low Our temperature. resultsand for n-nonane n-octane and n-nonane are results by Liresults et al.by[28]. study provides moremore open questions than comprehensive with previous Li et This al. [28]. This study provides open questions thanaa comprehensive understandingof ofgas-phase gas-phasereactions reactionsof ofOH OH with with n-alkanes n-alkanes below below 290 290 K K until until precise precise determinations determinations understanding of absolute absoluterate rate constants constants for for the the higher higher alkanes alkanes become become available. available. The The result result for for cyclooctane cyclooctane confirms confirms of the data data from from Sprengnether Sprengnether et et al. al. [31], [31], however, however,data data at at higher higher temperatures temperatures are are desirable desirable to to validate validate the the Arrhenius Arrheniusexpression expressionover overaawider widertemperature temperaturerange. range. the Our results for consistent with previous results by Li This Our for n-octane n-octaneand andn-nonane n-nonaneare are consistent with previous results byetLial.et[28]. al. [28]. study will help to provide a more comprehensive understanding of gas-phase reactions of OH This study will help to provide a more comprehensive understanding of gas-phase reactions of with OH n-alkanes below 290 290 K. The result forfor cyclooctane confirms the with n-alkanes below K. The result cyclooctane confirms thedata datafrom fromSprengnether Sprengnether et et al. [31], however,data dataat athigher highertemperatures temperaturesare aredesirable desirableto to validate validate the the Arrhenius Arrhenius expression expressionover over aa wider wider however, temperaturerange. range. temperature Badwin and Walker (1979) Atkinson et al. (1982b) Harris and Kerr (1988) Behnke et al. (1988) Abbatt et al. (1990) Talukdar et al. (1994) Donahue et al. (1998) DeMore and Bayes (1999) Pang et al. (2011) This work Recommendation (Atkinson, 2003) Fit to k = A e-B/T

Greiner (1970) Perry et al. (1976) Atkinson and Aschman (1984) Droege and Tully (1986) Behnke et al. (1988) Abbatt et al. (1990) Talukdar et al. (1994) Donahue et al. (1998) DeMore and Bayes (1999) This work Recommendation (Atkinson, 2003) Fit to k = A e-B/T

(Calvert et al., 2008) Arrhenius fit (Pang et al., 2011)

(Calvert et al., 2008)

n-Butane

n-Pentane

-1

-1

-1

cm molecule s )

-1

cm molecule s )

100

10

k (10

-12

k (10

-12

-3

-3

10

1 0

1

2

3

4

5

-1

1000/T (K )

1 0

1

2

3

1000/T (K-1)

(a)

(b) Figure 4. Cont.

4

5

Atmosphere 2018, 9, 320 Atmosphere 2018, 9, x FOR PEER REVIEW

8 of 16 8 of 16 Atkinson et al. (1982a) Klöpffer et al. (1986) Behnke et al. (1987) Behnke et al. (1988) Ferrari et al. (1996) Koffend and Cohen (1996) Wilson et al. (2006) Pang et al. (2011) Crawford et al. (2011) This work Recommendation (Atkinson, 2003) Arrhenius expression (Wilson et al., 2006) Fit to k = A e-B/T

Atkinson et al. (1982a) Klein et al. (1984) Behnke et al. (1988) Koffend and Cohen (1996) Donahue et al. (1998) DeMore and Bayes (1999) Crawford et al. (2011) This work Fit to k = A e-B/T * Fit to k = A T e-B/T * Fit to k = A T 2 e-B/T * (* Atkinson, 2003) Fit to k = A e-B/T (Calvert et al., 2008) Arrhenius expression (Crawford et al. 2011)

(Calvert et al., 2008) Arrhenius fit (Pang et al., 2011)

100

n-Heptane

-3

-3

-1

-1

-1

cm molecule s )

n-Hexane

-1

cm molecule s )

100

10

k (10

k (10

-12

-12

10

0

1

2

3

4

5

0

1

2

1000/T (K-1)

3

4

5

1000/T (K-1)

(c)

(d) Atkinson et al. (1982a) Behnke et al. (1988) Nolting et al. (1988) Koffend and Cohen (1996) Ferrari et al. (1996) Coeur et al. (1998) Colomb et al. (2004) Li et al. (2006) Pang et al. (2011) This work Recommendation (Atkinson, 2003) Arrhenius expression (Li et al., 2006) Arrhenius fit (Pang et al., 2011) Arrhenius expression (Warneck and Williams, 2012)

Greiner (1970) Atkinson et al. (1982a) Behnke et al. (1988) Nolting et al. (1988) Koffend and Cohen (1996) Anderson et al. (2003) Wilson et al. (2006) Li et al. (2006) This work Recommendation (Atkinson, 2003) Arrhenius expression (Li et al., 2006) Fit to k = A e-B/T (Calvert et al., 2008)

100

k (10-12 cm-3 molecule-1 s-1)

k (10-12 cm-3 molecule-1 s-1)

100

n-Octane

10

0

1

2

3

4

n-Nonane

10

5 0

1000/T (K-1)

1

2

3

1000/T (K-1)

(e)

(f) Figure 4. Cont.

4

5


9 of 16 9 of 16

Cyclooctane

10

k (10

-12

-3

-1

-1

cm molecule s )

Donahue et al. (1998) Sprengnether et al. (2009) Aschmann et al. (2011) Singh et al. (2013) This work Calvert et al. (2008) Sprengnether et al. (2009) Singh et al. (2013)

2.0

2.5

3.0

3.5

4.0

4.5

5.0

1000/T (K-1)

(g) Figure 4. Arrhenius plots of the rate data for the reaction of OH radicals with straight-chain alkanes Figure 4. Arrhenius plots of the rate data for the reaction of OH radicals with straight-chain alkanes and cyclooctane in comparison with previous studies [25,39–49]. and cyclooctane in comparison with previous studies [25,39–49].

(2) Figure 5 shows the Arrhenius plot for the reaction of branched-chain alkanes with OH (2) Figure 5 shows the we Arrhenius plot the reaction of branched-chain alkanes radicals. For the first time, report the ratefor constant below 290 K for the reactions of OH with radicals OHwith radicals. For the first time, we report the rate constant below 290 K for the 2,2,4-trimethylpentane, 2,2-dimethylpentane, 2,2,3,3-tetramethylbutane reactions and 2,2of OH radicals with 2,2,4-trimethylpentane, 2,2-dimethylpentane, 2,2,3,3-tetramethylbutane and dimethylhexane. The reaction rate constant data for 2,2-dimethylbutane, 2,2,4-trimethylpentane and 2,2-dimethylhexane. The reaction rate constant data for 2,2-dimethylbutane, 2,2,4-trimethylpentane 2,2,3,3-tetramethylbutane are consistent with previous results and follow the existing Arrhenius andexpressions 2,2,3,3-tetramethylbutane are consistent with previous results and follow the existing Arrhenius (or non-linear fit) as well. For 2,2-dimethylbutane, we give an estimated Arrhenius fit to expressions (or non-linear fit) as well. For 2,2-dimethylbutane, we give an estimated Arrhenius fit to −B/T k = ATe by applying the value of activation energy (B = 445 K) estimated by Kwok and Atkinson −B/T k = ATe applying the value ofofactivation = 445cm K)3 estimated Atkinson [50] [50] andby obtain an expression k = 3.33 ×energy 10−14 T(Be–445/T molecule−1bys−1Kwok . For and 2,2-dimethylpentane − 14 − 445/T 3 − 1 − 1 andand obtain an expression of kcalculated = 3.33 × 10values T e(based on cm a molecule s . For 2,2-dimethylpentane 2,2-dimethylhexane, structure-activity relationship (SAR) [51]) at androom 2,2-dimethylhexane, calculated values (based on a structure-activity relationship (SAR) [51])The temperature are given for these two compounds to evaluate the temperature dependence. at room temperature are given for these two compounds to evaluate the temperature dependence. results of 2,2-dimethylpentane fit well to the non-linear fit provided by Badra and Farooq [52]. A SAR Theestimation results of 2,2-dimethylpentane fit well to the and non-linear fit provided Badra andestimation Farooq [52]. is given for 2,2-dimethylhexane, our data fall very by close to the line. A SAR estimation is given for 2,2-dimethylhexane, and our data fall very close to the estimation Nevertheless, in order to give a more accurate evaluation of the temperature dependence of 2,2line.dimethylhexane, Nevertheless, inmore order to give a more evaluation of the temperature dependence experimental dataaccurate are needed to establish the temperature dependenceofand 2,2-dimethylhexane, more experimental data are needed tocompound. establish the temperature dependence and hereafter to develop the Arrhenius expression for this hereafter to develop the Arrhenius expression for this compound. (3) Regarding the activated aromatic hydrocarbons, our rate data points at 288 K and 248 K coincide well with the existing data points, showing that the rate constant for these reactions had a negative dependence on temperature at T ≤ 298 K, which indicates a coherent pathway of electrophilic addition of the OH radical to the aromatic ring [23]. Combining our results with the available literature data (Figure 5), we here give Arrhenius expressions for o-xylene, p-xylene and ethylbenzene: 6.24 × 10−12 e(203 ± 126)/T cm3 molecule−1 s−1 , 1.03 × 10−11 e(62 ± 116)/T cm3 molecule−1 s−1 and 6.90 × 10−12 e(8 ± 135)/T cm3 molecule−1 s−1 , respectively (SI, Table S3). All previously reported data points for ethylbenzene existed around room temperature, which caused great uncertainties in determining the activation energy. Further investigations at other temperatures lower than 298 K are required to give a more precise evaluation of the Arrhenius expression for ethylbenzene.


10 of 16


10 of 16

Atkinson et al. (1984) Harris and Kerr (1988) Badra and Farooq (2015) This work Recommendation (Atkinson 2003) Non-linear fit (Badra and Farooq, 2015) Fit to k = A T e-B/T (estimated from this work)

100

2,2,4-Trimethylpentane

-1

-1

-1

cm molecule s )

2,2-Dimethylbutane

-1

cm molecule s )

100

Greiner (1970) Atkinson et al. (1984) Bott and Cohen (1991) Badra and Farooq (2015) This work Recommendation (Atkinson, 2003) Non-linear fit (Badra and Farooq, 2015)

10

k (10

k (10

-12

-12

-3

-3

10

1

1 0

1

2

3

4

0

5

1

2

3

1000/T (K )

1000/T (K-1)

(a)

(b)

-1

4

5

Greiner (1970) Baldwin et al. (1979) Atkinson et al. (1984) Tully et al. (1985) Bott and Cohen (1991) Sivaramakrishnan and Michael (2009) This work Fit to k = A T 2 e-B/T

Calculation value (Kwok and Atkinson, 1995) Finlayson Pitts and Pitts (2000) Badra and Farooq (2015) This work SAR estimation k = A T e-B/T

(Cohen, 1991) Recommendation (Atkinson, 2003) Fit to k = A e-B/T

(Calvert et al., 2008) Non-linear fit (Badra and Farooq, 2015)

(Calvert et al., 2008) Non-linear fit (Sivaramakrishnan and Michael, 2009)

100

2,2,3,3,-Tetramethylbutane

-1

-1

cm molecule s )

10

-12

-3

10

k (10

k (10

-12

3 -1 -1 cm molecule s )

2,2-Dimethylpentane

1

1 0

1

2

3

4

5

0

1000/T (K-1)

1

2

3

1000/T (K-1)

(c)

(d) Figure 5. Cont.

4

5

k (10-12cm3 molecule-1 s-1)

2,2-Dimethylhexane

10 Atmosphere 2018, 9, 320 Atmosphere 2018, 9, x FOR PEER REVIEW

1 100

11 of 16 11 of 16 Calculation value (Kwok and Atkinson, 1995) This work SAR estimation k = A T2 e-B/T (Calvert et al., 2008)

0

1

2

3

4

5

k (10-12cm3 molecule-1 s-1)

1000/T (K-1)

2,2-Dimethylhexane

(e)

Figure 5. Arrhenius plots of the rate data for the reaction of OH radicals with branched-chain alkanes [47,53–58]. 10

(3) Regarding the activated aromatic hydrocarbons, our rate data points at 288 K and 248 K coincide well with the existing data points, showing that the rate constant for these reactions had a negative dependence on temperature at T ≤ 298 K, which indicates a coherent pathway of electrophilic addition of the OH radical to the aromatic ring [23]. Combining our results with the available literature data (Figure 5), 1 we here1 give Arrhenius expressions for5 o-xylene, p-xylene and 0 2 3 4 −12 (203 ± 126)/T 3 −1 −1 −11 (62 ± 116)/T ethylbenzene: 6.24 × 10 e cm molecule 1000/T s , 1.03 × 10 e cm3 molecule−1 s−1 and 6.90 × (K-1) −12 (8 ± 135)/T 3 −1 −1 10 e cm molecule s , respectively (SI, (e) Table S3). All previously reported data points for ethylbenzene existed around room temperature, which caused great uncertainties in determining the Figureenergy. plots ofofthe rate data the reaction of OH with branched-chain alkanes activation Further investigations atfor other temperatures lower than 298 K branched-chain are required to give Figure 5.5. Arrhenius Arrhenius plots the rate data for the reaction ofradicals OH radicals with [47,53–58]. alkanes [47,53–58]. a more precise evaluation of the Arrhenius expression for ethylbenzene. (3) Regarding the activatedHansen aromatic hydrocarbons, our rate data points at 288 K and 248 K et al. (1975) Davis et al. (1975) coincide well with the existing data points, showing that the rate constant for these reactions had a Perry et al. (1977) Tully et al. (1981) negative dependence on temperature at T ≤ 298 K, which indicates a coherent pathway of electrophilic Wahner et al. (1983) Hansen et al. (1975) Witte et al. (1986) addition of the OH radical to the aromatic ring [23]. Combining our results the available Daviswith et al. (1975) Wallington et al. (1987) Perry et al. (1977) Knispel et al. (1990) literature data (Figure 5), weGoumri here give Arrhenius expressions for o-xylene, p-xylene and Tully et al. (1981) et al. (1991) Atkinson and−1 Aschmann (1989) Semadeni al. (1995) 3 et −1 s−1, 1.03 × 10−11 e(62 ± 116)/T cm3 molecule ethylbenzene: 6.24 × 10−12 e(203 ± 126)/T cm molecule s−1 and 6.90 × Knispel et al. (1990) Anderson et al. (2003) Semadeni et al. (1995) This work −12 (8 ± 135)/T 3 −1 −1 10 e cm molecule s , respectively (SI, Table S3). All previously reported data points for Anderson and Hites (1996) Arrhenius expression This work (Witte et al., 1986) ethylbenzene existed around room temperature, which caused great uncertainties in determining the Arrhenius expression Arrhenius expression (Semadeni et al., 1995) (Semadeni et al., 1995) activation energy. Further investigations at other temperatures lower than 298 K are required to give Recommendation Recommendation (IUPAC, 2008) 2008) a more precise evaluation of the (IUPAC, Arrhenius expression20for ethylbenzene. 4

1 0.9 0.8 0.7

0.5 0.4 2.5

3.0

3.5

1000/T (K-1)

4

(a)

5 4

2 2.5

3.0

3.5

1000/T (K-1)

20

(b)

-1 -1

Hansen et al. (1975) Davis et al. (1975) Perry et al. (1977) Tully et al. (1981) Atkinson and Aschmann (1989) Knispel et al. (1990) Semadeni et al. (1995) Anderson and Hites (1996) This work Arrhenius expression (Semadeni et al., 1995) Recommendation 4.0 4.5 5.0 (IUPAC, 2008)

6

Benzene

Toluene

10 Figure 6. Cont. 9

2

3 -12

k (10

10 9 8 7

3

k (10-12 cm3 molecule-1 s-1)

3

Hansen et al. (1975) Davis et al. (1975) Perry et al. (1977) Tully et al. (1981) Wahner et al. (1983) Witte et al. (1986) Wallington et al. (1987) Knispel et al. (1990) Goumri et al. (1991) Semadeni et al. (1995) Anderson et al. (2003) This work Arrhenius expression (Witte et al., 1986) Arrhenius expression (Semadeni et al., 1995) Recommendation 4.0 4.5 (IUPAC, 2008)

k (10-12 cm3 molecule-1 s-1)

-1

k (10

-12

3

2

0.6

cm molecule s )

Toluene

Benzene

-1

cm molecule s )

3

1 0.9 0.8 0.7

8 7 6 5 4 3

0.6 0.5

2

0.4 2.5

3.0

3.5

1000/T (K-1)

(a)

4.0

4.5

2.5

3.0

3.5

4.0

1000/T (K-1)

(b)

4.5

5.0


12 of 16 12 of 16 Doyle et al. (1975) Hansen et al. (1975) Davis (1977) Perry et al. (1977) Ravishankara et al. (1978) Nicovich et al. (1981) Ohta and Ohyama, (1985) Atkinson and Aschmann (1989) Mehta et al. (2009) Alarcón et al. (2015) This work Arrhenius expression (Alarcón et al., 2015) Arrhenius expression (this work)

Doyle et al. (1975) Hansen et al. (1975) Perry et al. (1977) Davis (1977) Ravishankara et al. (1978) Nicovich et al. (1981) Atkinson and Aschmann (1989) Anderson et al. (2003) Mehta et al. (2009) This work Arrhenius expression (from this work) 50

50 40

o-Xylene -1

cm molecule s )

30

20

-12

3

3

20

k (10

-12

k (10

p-Xylene

30

-1

-1

-1

cm molecule s )

40

10 9 8 7

10 9 8 7 6

6

5

5 2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

2.8

4.4

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

-1

1000/T (K-1)

1000/T (K )

(c)

(d) Lloyd et al. (1976) Davis et al. (1977) Ravishankara et al. (1978) Ohta and Ohyama (1985) Anderson et al. (2003) This work Arrhenius expression (from this work)

Ethylbenzene 10 9 8 7 6 5

k (10

-12

3

-1

-1

cm molecule s )

20

4 3

2 2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

1000/T (K-1)

(e) Figure 6. Arrhenius plots of the rate data for the reaction of OH radicals with aromatic hydrocarbons Figure 6. Arrhenius plots of the rate data for the reaction of OH radicals with aromatic hydrocarbons [33,34,59–67]. [33,34,59–67].

5. Conclusions 5. Conclusions In summary, this study has reported the rate constant of gaseous OH radicals with 17 hydrocarbons In summary, this study has reported the rate constant of gaseous OH radicals with 17 at 288 K and 248 K. The results have proven the capability of our simulation chamber for atmospheric hydrocarbons at 288 K and 248 K. The results have proven the capability of our simulation chamber chemistry study. Data obtained from this work are consistent with previous studies, supplementing the for atmospheric chemistry study. Data obtained from this work are consistent with previous studies, existing database. Our data on n-hexane agree well with the recommended Arrhenius expression supplementing the existing database. Our on n-hexane agree well with the recommended −1 sdata −1 [4]) (k = 1.82 × 10−17 T 2 e361/T cm3 molecule over the temperature range from 290 to 970 K. Arrhenius expression (k = 1.82 × 10−17 T 2e361/T cm3 molecule−1 s −1[4]) over the temperature range from Using the activation energy recommended by Kwok and Atkinson [50] for 2,2-dimethylbutane from 290 to 970 K. Using the activation energy recommended by Kwok and Atkinson [50] for 2,2an SAR calculation (B = 445 K), we obtain the Arrhenius expression k = 3.33 × 10−14 T e−445/T dimethylbutane an SAR calculation (B = 445 K), we obtain the Arrhenius expression k = 3.33 × 3 molecule−1 sfrom −1 . This cm−14 study reports experimental results for the rate constant of the gas phase −445/T 3 10 T e cm molecule−1 s−1. This study reports experimental results for the rate constant of the gas reaction of 2,2-dimethylhexane with OH, extending the homologous series of the 2,2-dimethylalkanes. phase reaction of 2,2-dimethylhexane with OH, extending the homologous series of the 2,2dimethylalkanes. Data obtained from this study will help to give a more comprehensive understanding to evaluate the atmospheric behavior of this compound.


13 of 16

Data obtained from this study will help to give a more comprehensive understanding to evaluate the atmospheric behavior of this compound. For aromatic hydrocarbons, we reported the first determination of a rate constant for the reaction of OH radicals with ethylbenzene below the atmospheric sea level temperature (T ≤ 288 K). Our data points agree with the existing results from previous research. Results from this work will help to evaluate the atmospheric degradations of n-alkanes, branched-chain alkanes, and aromatic hydrocarbons with better precision, especially in the lower and middle troposphere. Supplementary Materials: The following are available online at http://www.mdpi.com/2073-4433/9/8/320/s1, Figure S1: Schematic flowchart of the sample enrichment system connected with gas chromatographic analysis of the gas phase in the smog chamber, Figure S2: Dosage of methyl nitrite into the smog chamber, using a twin of gas containers. This method warrants a fairly constant production of OH, Figure S3: Decrease of the hydrocarbon concentrations (normalized by n-perfluorohexane) by the reaction with OH during a smog chamber run at 248 K, Figure S4: Plots of ln (c0 /ct ) of hydrocarbons versus toluene (reference substance) from data points of three experimental runs at 288 K, respectively (5, # and distinguish data points from different experimental runs), Figure S5: Plots of ln (c0 /ct ) of hydrocarbons versus toluene (reference substance) from data points of two experimental runs at 248 K, respectively (5 and # distinguish data points from different experimental runs), Figure S6: Arrhenius plots of the rate constant for the reaction of OH radicals with n-heptane, Table S1: Studies below room temperature for the reaction of OH radicals with hydrocarbons, Table S2: Rate constants for the reaction of OH radicals with hydrocarbons at 248 K, Table S3: Arrhenius parameters A and B corresponding to the equation kOH = Ae(−B/T) . Author Contributions: Conceptualization, C.Z.; Experiments, L.H. and F.S.; Data Analysis, L.H. and F.S.; Writing-Original Draft Preparation, L.H.; Writing-Review & Editing, L.H., F.S. and C.Z.; Supervision, C.Z.; Funding Acquisition, C.Z. Funding: This research was funded by the European Community through the EUROCHAMP project. This publication was funded by the German Research Foundation (DFG) and the University of Bayreuth in the funding program “Open Access Publishing”. Acknowledgments: This work is in memoriam to Heinz-Ulrich Krüger (†) for his enormous technical support and discussions for the primary data. Conflicts of Interest: The authors declare no conflict of interest.

References 1. 2. 3. 4. 5.

6. 7. 8. 9. 10. 11.

Koppmann, R. Chemistry of Volatile Organic Compounds in the Atmosphere. In Handbook of Hydrocarbon and Lipid Microbiology; Springer: Heidelberg, Germany, 2010; pp. 267–277. Atkinson, R. Atmospheric Chemistry of VOCs and NOx . Atmos. Environ. 2000, 34, 2063–2101. [CrossRef] Carter, W.P.L.; Pierce, J.A.; Luo, D.; Malkina, I.L. Environmental Chamber Study of Maximum Incremental Reactivities of Volatile Organic Compounds. Atmos. Environ. 1995, 29, 2499–2511. [CrossRef] DeMore, W.B.; Bayes, K.D. Rate Constants for the Reactions of Hydroxyl Radical with Several Alkanes, Cycloalkanes, and Dimethyl Ether. J. Phys. Chem. A 1999, 103, 2649–2654. [CrossRef] Doyle, G.L.; Lloyd, A.C.; Darnall, K.R.; Winer, A.M.; Pitts, J.N., Jr. Gas Phase Kinetic Study of Relative Rates of Reaction of Selected Aromatic Compounds with Hydroxyl Radicals in an Environmental Chamber. Environ. Sci. Technol. 1975, 9, 237–241. [CrossRef] Greiner, N.R. Hydroxyl Radical Kinetics by Kinetic Spectroscopy. VI. Reactions with Alkanes in the Range 300–500 K. J. Chem. Phys. 1970, 53, 1070–1076. [CrossRef] Hansen, D.A.; Atkinson, R.; Pitts, J.N. Rate Constants for the Reaction of Hydroxyl Radicals with a Series of Aromatic Hydrocarbons. J. Phys. Chem. 1975, 79, 1763–1766. [CrossRef] Koffend, J.B.; Cohen, N. Shock Tube Study of OH Reactions with Linear Hydrocarbons near 1100 K. Int. J. Chem. Kinet. 1996, 28, 79–87. [CrossRef] Nicovich, J.M.; Thompson, R.L.; Ravishankara, A.R. Kinetics of the Reactions of the Hydroxyl Radical with Xylenes. J. Phys. Chem. 1981, 85, 2913–2916. [CrossRef] Nolting, F.; Behnke, W.; Zetzsch, C. A Smog Chamber for Studies of the Reactions of Terpenes and Alkanes with Ozone and OH. J. Atmos. Chem. 1988, 6, 47–59. [CrossRef] Perry, R.A.; Atkinson, R.; Pitts, J.N. Kinetics and Mechanism of the Gas Phase Reaction of Hydroxyl Radicals with Aromatic Hydrocarbons over the Temperature Range 296–473 K. J. Phys. Chem. 1977, 81, 296–304. [CrossRef]


12. 13.

14. 15. 16.

17.

18. 19.

20.

21. 22. 23.

24.

25. 26. 27. 28.

29.

30.

31.

14 of 16

Tully, F.P.; Koszykowski, M.L.; Stephen Binkley, J. Hydrogen-Atom Abstraction from Alkanes by OH. I. Neopentane and Neooctane. Symp. Int. Combust. 1985, 20, 715–721. [CrossRef] Atkinson, R. Kinetics and Mechanisms of the Gas-Phase Reactions of the Hydroxyl Radical with Organic Compounds. J. Phys. Chem. Ref. Data 1989. Available online: https://srd.nist.gov/JPCRD/jpcrdM1.pdf (accessed on 8 January 2018). Finlayson, B.J.; Pitts, J.N. Photochemistry of the Polluted Troposphere. Science 1976, 192, 111–119. [CrossRef] [PubMed] Hecht, T.A.; Seinfeld, J.H.; Dodge, M.C. Generalized Kinetic Mechanism for Photochemical Smog. Environ. Sci. Technol. 1974, 8, 327–339. [CrossRef] Pitts, J.N., Jr.; Darnall, K.; Winer, A.; McAfee, J. Mechanisms of Photochemical Reactions in Urban Air. Volume II. Chamber Studies. 1977. Available online: https://cfpub.epa.gov/si/si_public_record_Report. cfm?dirEntryId=40180 (accessed on 8 January 2018). Rohrer, F.; Bohn, B.; Brauers, T.; Brüning, D.; Johnen, F.-J.; Wahner, A.; Kleffmann, J. Characterisation of the Photolytic HONO-Source in the Atmosphere Simulation Chamber SAPHIR. Atmos. Chem. Phys. 2005, 5, 2189–2201. [CrossRef] Zador, J.; Turányi, T.; Wirtz, K.; Pilling, M.J. Measurement and Investigation of Chamber Radical Sources in the European Photoreactor (EUPHORE). J. Atmos. Chem. 2006, 55, 147–166. [CrossRef] Karl, M.; Brauers, T.; Dorn, H.-P.; Holland, F.; Komenda, M.; Poppe, D.; Rohrer, F.; Rupp, L.; Schaub, A.; Wahner, A. Kinetic Study of the OH-isoprene and O3 -isoprene Reaction in the Atmosphere Simulation Chamber, SAPHIR. Geophys. Res. Lett. 2004, 31. [CrossRef] Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; et al. Design and Characterization of a Smog Chamber for Studying Gas-Phase Chemical Mechanisms and Aerosol Formation. Atmos. Meas. Tech. 2014, 7, 301–313. [CrossRef] Harris, S.J.; Kerr, J.A. Relative Rate Measurements of Some Reactions of Hydroxyl Radicals with Alkanes Studied under Atmospheric Conditions. Int. J. Chem. Kinet. 1988, 20, 939–955. [CrossRef] Talukdar, R.K.; Mellouki, A.; Gierczak, T.; Barone, S.; Chiang, S.-Y.; Ravishankara, A.R. Kinetics of the Reactions of OH with Alkanes. Int. J. Chem. Kinet. 1994, 26, 973–990. [CrossRef] Tully, F.P.; Ravishankara, A.R.; Thompson, R.L.; Nicovich, J.M.; Shah, R.C.; Kreutter, N.M.; Wine, P.H. Kinetics of the Reactions of Hydroxyl Radical with Benzene and Toluene. J. Phys. Chem. 1981, 85, 2262–2269. [CrossRef] Mohanakumar, K. Stratosphere Troposphere Interactions: An Introduction; Springer: Dordrecht, The Netherlands, 2008; Available online: https://books.google.com.hk/books?hl=zh-TW&lr=&id=pAQDbLQXnksC& oi=fnd&pg=PR7&dq=Stratosphere+Troposphere+Interactions:+An+Introduction&ots=30W_Js-QWU& sig=6KPUegpfd-54aoOID9vU94VTeIM&redir_esc=y#v=onepage&q=Stratosphere%20Troposphere% 20Interactions%3A%20An%20Introduction&f=false (accessed on 8 January 2018). Droege, A.T.; Tully, F.P. Hydrogen Atom Abstraction from Alkanes by Hydroxyl. 5. n-Butane. J. Phys. Chem. 1986, 90, 5937–5941. [CrossRef] Donahue, N.M.; Clarke, J.S. Fitting Multiple Datasets in Kinetics: N-Butane + OH → Products. Int. J. Chem. Kinet. 2004, 36, 259–272. [CrossRef] Atkinson, R. Kinetics of the Gas-Phase Reactions of OH Radicals with Alkanes and Cycloalkanes. Atmos. Chem. Phys. 2003, 3, 2233–2307. [CrossRef] Li, Z.; Singh, S.; Woodward, W.; Dang, L. Kinetics Study of OH Radical Reactions with N-Octane, n-Nonane, and n-Decane at 240–340 K Using the Relative Rate/Discharge Flow/Mass Spectrometry Technique. J. Phys. Chem. A 2006, 110, 12150–12157. [CrossRef] [PubMed] Crawford, M.A.; Dang, B.; Hoang, J.; Li, Z. Kinetic Study of OH Radical Reaction with N-Heptane and n-Hexane at 240–340K Using the Relative Rate/Discharge Flow/Mass Spectrometry (RR/DF/MS) Technique. Int. J. Chem. Kinet. 2011, 43, 489–497. [CrossRef] Wilson, E.W.; Hamilton, W.A.; Kennington, H.R.; Evans, B.; Scott, N.W.; DeMore, W.B. Measurement and Estimation of Rate Constants for the Reactions of Hydroxyl Radical with Several Alkanes and Cycloalkanes. J. Phys. Chem. A 2006, 110, 3593–3604. [CrossRef] [PubMed] Sprengnether, M.M.; Demerjian, K.L.; Dransfield, T.J.; Clarke, J.S.; Anderson, J.G.; Donahue, N.M. Rate Constants of Nine C6−C9 Alkanes with OH from 230 to 379 K: Chemical Tracers for [OH]. J. Phys. Chem. A 2009, 113, 5030–5038. [CrossRef] [PubMed]


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33.

34.

35.

36. 37. 38. 39. 40.

41.

42. 43. 44. 45. 46. 47. 48. 49.

50.

51.

52. 53.

15 of 16

Singh, S.; de Leon, M.F.; Li, Z. Kinetics Study of the Reaction of OH Radicals with C5–C8 Cycloalkanes at 240–340 K Using the Relative Rate/Discharge Flow/Mass Spectrometry Technique. J. Phys. Chem. A 2013, 117, 10863–10872. [CrossRef] [PubMed] Witte, F.; Urbanik, E.; Zetzsch, C. Temperature Dependence of the Rate Constants for the Addition of Hydroxyl to Benzene and to Some Monosubstituted Aromatics (Aniline, Bromobenzene, and Nitrobenzene) and the Unimolecular Decay of the Adducts. Part 2. Kinetics into a Quasi-Equilibrium. J. Phys. Chem. 1986, 90, 3251–3259. [CrossRef] Mehta, D.; Nguyen, A.; Montenegro, A.; Li, Z. A Kinetic Study of the Reaction of OH with Xylenes Using the Relative Rate/Discharge Flow/Mass Spectrometry Technique. J. Phys. Chem. A 2009, 113, 12942–12951. [CrossRef] [PubMed] Alarcón, P.; Bohn, B.; Zetzsch, C. Kinetic and Mechanistic Study of the Reaction of OH Radicals with Methylated Benzenes: 1,4-Dimethyl-, 1,3,5-Trimethyl-, 1,2,4,5-, 1,2,3,5- and 1,2,3,4-Tetramethyl-, Pentamethyl-, and Hexamethylbenzene. Phys. Chem. Chem. Phys. 2015, 17, 13053–13065. [CrossRef] [PubMed] Warneck, P. Chemistry of the Natural Atmosphere, 2nd ed.; Academic Press: San Diego, CA, USA, 1999. IUPAC. Preferred Value for Toluene of the IUPAC Task Group on Atmospheric Chemical Kinetic Data Evaluation. Available online: http://Iupac.Pole-Ether.Fr/ (accessed on 8 January 2018). Doumaux, A.R.; Downey, J.J.M.; Henry, J.P.; Hurt, J.M. Preparation of Methyl or Ethyl Nitrite from the Corresponding Alcohols in a Vapor Phase Process. European Patent No. EP0057143B1, 23 January 1981. Donahue, N.M.; Anderson, J.G.; Demerjian, K.L. New Rate Constants for Ten OH Alkane Reactions from 300 to 400 K: An Assessment of Accuracy. J. Phys. Chem. A 1998, 102, 3121–3126. [CrossRef] Abbatt, J.P.D.; Demerjian, K.L.; Anderson, J.G. A New Approach to Free-Radical Kinetics: Radially and Axially Resolved High-Pressure Discharge Flow with Results for Hydroxyl + (Ethane, Propane, n-Butane, n-Pentane) .Fwdarw. Products at 297 K. J. Phys. Chem. 1990, 94, 4566–4575. [CrossRef] Behnke, W.; Holländer, W.; Koch, W.; Nolting, F.; Zetzsch, C. A Smog Chamber for Studies of the Photochemical Degradation of Chemicals in the Presence of Aerosols. Atmos. Environ. (1967) 1988, 22, 1113–1120. [CrossRef] Atkinson, R.; Aschmann, S.M. Rate Constants for the Reaction of OH Radicals with a Series of Alkenes and Dialkenes at 295 ± 1 K. Int. J. Chem. Kinet. 1984, 16, 1175–1186. [CrossRef] Atkinson, R.; Aschmann, S.M.; Carter, W.P.L.; Winer, A.M.; Pitts, J.N. Kinetics of the Reactions of OH Radicals with N-Alkanes at 299 ± 2 K. Int. J. Chem. Kinet. 1982, 14, 781–788. [CrossRef] Ferrari, C.; Roche, A.; Jacob, V.; Foster, P.; Baussand, P. Kinetics of the Reaction of OH Radicals with a Series of Esters under Simulated Conditions at 295 K. Int. J. Chem. Kinet. 1996, 28, 609–614. [CrossRef] Behnke, W.; Nolting, F.; Zetzsch, C. A Smog Chamber Study on the Impact of Aerosols on the Photodegradation of Chemicals in the Troposphere. J. Aerosol Sci. 1987, 18, 65–71. [CrossRef] Coeur, C.; Jacob, V.; Foster, P.; Baussand, P. Rate Constant for the Gas-Phase Reaction of Hydroxyl Radical with the Natural Hydrocarbon Bornyl Acetate. Int. J. Chem. Kinet. 1998, 30, 497–502. [CrossRef] Calvert, J.G.; Derwent, R.G.; Orlando, J.J.; Tyndall, G.S.; Wallington, T.J. Mechanisms of Atmospheric Oxidation of the Alkanes; Oxford University Press: New York, NY, USA, 2008. Atkinson, R.; Aschmann, S.M.; Winer, A.M.; Pitts, J.N. Rate Constants for the Reaction of OH Radicals with a Series of Alkanes and Alkenes at 299 ± 2 K. Int. J. Chem. Kinet. 1982, 14, 507–516. [CrossRef] Pang, G.A.; Hanson, R.K.; Golden, D.M.; Bowman, C.T. High-Temperature Measurements of the Rate Constants for Reactions of OH with a Series of Large Normal Alkanes: N-Pentane, n-Heptane, and n-Nonane. Zeitschrift für Physikalische Chemie 2011, 225, 1157–1178. [CrossRef] Kwok, E.S.C.; Atkinson, R. Estimation of Hydroxyl Radical Reaction Rate Constants for Gas-Phase Organic Compounds Using a Structure-Reactivity Relationship: An Update. Atmos. Environ. 1995, 29, 1685–1695. [CrossRef] Jenkin, M.E.; Valorso, R.; Aumont, B.; Rickard, A.R.; Wallington, T.J. Estimation of Rate Coefficients and Branching Ratios for Gas-Phase Reactions of OH with Aliphatic Organic Compounds for Use in Automated Mechanism Construction. Atmos. Chem. Phys. 2018, 18, 9297–9328. [CrossRef] Badra, J.; Farooq, A. Site-Specific Reaction Rate Constant Measurements for Various Secondary and Tertiary H-Abstraction by OH Radicals. Combust. Flame 2015, 162, 2034–2044. [CrossRef] Atkinson, R.; Carter, W.P.L.; Aschmann, S.M.; Winer, A.M.; Pitts, J.N. Kinetics of the Reaction of Oh Radicals with a Series of Branched Alkanes at 297 ± 2 K. Int. J. Chem. Kinet. 1984, 16, 469–481. [CrossRef]


54. 55.

56. 57. 58. 59.

60.

61.

62.

63.

64. 65. 66. 67.

16 of 16

Bott, J.F.; Cohen, N. A Shock Tube Study of the Reactions of the Hydroxyl Radical with Several Combustion Species. Int. J. Chem. Kinet. 1991, 23, 1075–1094. [CrossRef] Baldwin, R.R.; Walker, R.W.; Walker, R.W. Addition of 2,2,3-Trimethylbutane to Slowly Reacting Mixtures of Hydrogen and Oxygen at 480 ◦ C. J. Chem. Soc. Faraday Trans. 1 Phys. Chem. Condens. Phases 1981, 77, 2157–2173. [CrossRef] Finlayson-Pitts, B.J.; Pitts, J.N., Jr. Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications, 1st ed.; Academic Press: San Diego, CA, USA, 1999. Sivaramakrishnan, R.; Michael, J.V. Rate Constants for OH with Selected Large Alkanes: Shock-Tube Measurements and an Improved Group Scheme. J. Phys. Chem. A 2009, 113, 5047–5060. [CrossRef] [PubMed] Cohen, N. Are Reaction Rate Coefficients Additive? Revised Transition State Theory Calculations for OH + Alkane Reactions. Int. J. Chem. Kinet. 1991, 23, 397–417. [CrossRef] Ravishankara, A.R.; Wagner, S.; Fischer, S.; Smith, G.; Schiff, R.; Watson, R.T.; Tesi, G.; Davis, D.D. A Kinetics Study of the Reactions of OH with Several Aromatic and Olefinic Compounds. Int. J. Chem. Kinet. 1978, 10, 783–804. [CrossRef] Anderson, R.S.; Czuba, E.; Ernst, D.; Huang, L.; Thompson, A.E.; Rudolph, J. Method for Measuring Carbon Kinetic Isotope Effects of Gas-Phase Reactions of Light Hydrocarbons with the Hydroxyl Radical. J. Phys. Chem. A 2003, 107, 6191–6199. [CrossRef] Semadeni, M.; Stocker, D.W.; Kerr, J.A. The Temperature Dependence of the OH Radical Reactions with Some Aromatic Compounds under Simulated Tropospheric Conditions. Int. J. Chem. Kinet. 1995, 27, 287–304. [CrossRef] Wallington, T.J.; Neuman, D.M.; Kurylo, M.J. Kinetics of the Gas Phase Reaction of Hydroxyl Radicals with Ethane, Benzene, and a Series of Halogenated Benzenes over the Temperature Range 234–438 K. Int. J. Chem. Kinet. 1987, 19, 725–739. [CrossRef] Knispel, R.; Koch, R.; Siese, M.; Zetzsch, C. Adduct Formation of OH Radicals with Benzene, Toluene, and Phenol and Consecutive Reactions of the Adducts with NOx and O2. Berichte der Bunsengesellschaft für Physikalische Chemie 1990, 94, 1375–1379. [CrossRef] Goumri, A.; Pauwels, J.F.; Devolder, P. Rate of the OH + C6H6 + He Reaction in the Fall-off Range by Discharge Flow and OH Resonance Fluorescence. Can. J. Chem. 1991, 69, 1057–1064. [CrossRef] Anderson, P.N.; Hites, R.A. OH Radical Reactions: The Major Removal Pathway for Polychlorinated Biphenyls from the Atmosphere. Environ. Sci. Technol. 1996, 30, 1756–1763. [CrossRef] Ohta, T.; Ohyama, T. A Set of Rate Constants for the Reactions of OH Radicals with Aromatic Hydrocarbons. Bull. Chem. Soc. Jpn. 1985, 58, 3029–3030. [CrossRef] Atkinson, R.; Aschmann, S.M. Rate Constants for the Gas-Phase Reactions of the OH Radical with a Series of Aromatic Hydrocarbons at 296 ± 2 K. Int. J. Chem. Kinet. 1989, 21, 355–365. [CrossRef] © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).