Gas-phase reaction of two unsaturated ketones with atomic Cl and O3: Kinetics and products

Article abstract of DOI:10.1039/c4cp05461j

The rate constants and products for the reactions of atomic Cl and O₃ molecule with 3-methyl-3-buten-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332) were determined in a 100 L Teflon chamber at 293 ± 1 K and atmospheric pressure. For MBO332 and MPO332, the rate constants measured with atomic Cl were (2.38 ± 0.26) × 10^-10 and (3.00 ± 0.34) × 10^-10 cm³ molecule^-1 s^-1 using the relative rate method. Using the absolute rate method, the rate constants with O₃ measured were (1.18 ± 0.21) × 10^-17 and (4.07 ± 0.45) × 10^-17 cm³ molecule^-1 s^-1. The products of these reactions were investigated by the proton-transfer-reaction mass spectrum (PTR-MS). The results indicated that the major products observed in the atomic Cl reaction were formaldehyde together with chloroacetone for MBO332, and acetaldehyde and CH₃C(O)C(O)Cl for MPO332. For O₃ reactions, butanedione and formaldehyde were the main products of MBO332, while butanedione and acetaldehyde were the main products of MPO332. Possible reaction mechanisms were proposed and discussed and the atmospheric implications of these reactions were also discussed.

Full text of DOI:10.1039/c4cp05461j

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Page 1 of 26
Physical Chemistry Chemical Physics
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Gas-phase reaction of two unsaturated ketones with Cl atom and O : kinetics and
3
products
1
a,b
Jing Wang , Li Zhou , Weigang Wang *, Maofa Ge *
a,b
a
a
3
4
5
6
7
8
9
a
Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of
Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190,
b
China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Abstract:
The rate constants and products for the reactions of Cl atom and O molecule with 3-methyl-3-buten
3
-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332) were determined in a 100 L Teflon
chamber at 293±1K and atmospheric pressure. For MBO332 and MPO332, the rate constants with Cl
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
-10
-10
atom measured were (2.38±0.26) ×10 and (3.00±0.34) ×10 cm molecule s using the relative
3
-1 -1
rate method. Using the absolute rate method, the rate constants with O measured were (1.18±0.21)
3
-17
-17
3
-1 -1
×10 and (4.07±0.45) ×10 cm molecule s . The products of these reactions were investigated by
the proton-transfer-reaction mass spectrum (PTR-MS). The results indicated that the major products
observed in the Cl atom reaction were formaldehyde together with chloroacetone for MBO332, and
acetaldehyde
and
CH
3
C(O)C(O)Cl
for
MPO332.
For
O
3
reactions,
butanedione and formaldehyde were the main products of MBO332,
while
butanedione and
acetaldehyde were the main products of MPO332. Possible reaction mechanisms were proposed and
discussed and atmospheric implications of these reactions were also discussed.
1
2
2
9
0
1
2
2
2
2
2
2
3
4
5
6
Introduction
*
Corresponding author.Tel: 86-10-62558682; Fax: 86-10-62559373; E-mail: wangwg@iccas.ac.cn
(
Wei-Gang Wang).
∗
Corresponding author.Tel: 86-10-62554518; Fax: 86-10-62559373; E-mail: gemaofa@iccas.ac.cn
Mao-Fa Ge).
(

Physical Chemistry Chemical Physics
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Owing to their significant global emission and reactivity towards atmospheric oxidants, volatile
1
organic compounds (VOCs) have great influence on atmospheric chemistry and radiative forcing .
-4
In the atmosphere, unsaturated oxygenated VOCs have been identified as considerable components
5
of organic compounds such as alcohols, ethers, esters, aldehydes, and ketones . They are released to
the atmosphere directly from biogenic and anthropogenic sources, and also formed from complex
6
secondary sources like degradation of hydrocarbons being in the atmosphere . Once in the
-8
troposphere, they will be subjected to undergo oxidation reactions by OH radical (mainly during the
9
molecule and Cl atom (in certain environment) , and they have a
day), NO
3
radical (at night), O
3
direct impact on atmospheric chemical processes via controlling ozone and secondary organic
1
0, 11
aerosol formation
.
3
3
3
4
4
4
4
7
8
9
0
1
2
3
Unsaturated ketones are ubiquitous parts among the VOCs mentioned above in the troposphere,
and they are expected to have a number of different sources. For example, 3-methyl-3-buten-2-one
(MBO332) has been observed from plants, biomass burning, residential wood and fuel
1
2-15
combustion
medicine plants in the Nepal and cut-induced agricultural grasslands
MPO332 have been found to be intermediate products in synthesis and catalytic industry
. Emissions of 3-methyl-3-penten-2-one (MPO332) have been reported to be from
1
6, 17
. In addition, MBO332 and
1
8-20
.
Therefore, it is necessary to acquire kinetics and mechanisms of gas-phase degradation of
4
4
4
5
unsaturated ketones for their environmental impact assessment.
Although oxidation of VOCs by OH radicals is considered to be the dominant sink for most
4
4
4
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5
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9
0
1
2
3
4
5
VOCs in the atmosphere, the ozonolysis and Cl atom reaction are also important removal processes
21-25
under certain environments
3
. It is recognized that O is reactive towards certain classes of
organics, especially the unsaturated compounds, and ozonolysis process contributes to OH radical
2
and secondary organic aerosol formation . Cl atom is also known to be extremely reactive towards
6
27,
VOCs with most rate coefficients higher by an order of magnitude or more than that of OH radical
2
8
. Cl-initiated photo-oxidation has been conventionally thought to be confined largely to the marine
2
9, 30
boundary layer and heavily industrialized urban areas
. However, recent field measurements of
and Cl ) has presented evidence for Cl
anthropogenically derived photolabile Cl precursors (ClNO
2
2
chemistry in continental regions remote from coastal regions, which implies that the reactions of Cl
atom may contribute more to the tropospheric degradation of VOCs in the polluted mid-continental

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regions
.
To date, the gas phase oxidations of MBO332 and MPO332 under atmospheric condition were
not fully understood. There were only few kinetic studies on MBO332 and MPO332, concerning the
32, 33
radical
rate constants for reactions of MBO332 and MPO332 with OH radical and NO
3
. In this
work, the first rate constants and products for the reactions of Cl atom and O with MBO332 and
3
MPO332 were investigated with the purpose of more complete understanding of MBO332 and
MPO332 degradation processes in the atmosphere. The experiments were carried out in a simulation
5
chamber under NOx-free conditions at 293±1K and a total pressure of 1.01×10 Pa. The data were
used to estimate the atmospheric lifetimes and the potential environmental impacts, which have the
potential to increase the atmospheric chemistry database.
Experimental Section
Smog chamber
The experiments were conducted in a light-tight smog chamber, in which a 100 L FEP Teflon
film bag was housed as the reactor. More information of the chamber has been detailed in our
3
4, 35
previous work
. Briefly, the flexible Teflon chamber that maintains atmospheric pressure during
experiments was surrounded by a set of six UV fluorescent lamps (Philips TUV G1336W).
Temperature inside the chamber was regulated using a self-made temperature controller with an
accuracy of ±1 K for experimental conditions. An inlet and an outlet made of Teflon were used for
the introduction of reactants and gas sampling, and Teflon tubes were used to link the chamber and
analytical instruments. The liquid reactants were introduced into the chamber by flushing the carrier
gas through a 3-way glass tube which contained certain amount of compounds, warming where
necessary. A zero air gas generator (Thermo 111-D3R) was used to produce VOC-free air as carrier
gas for reactants and bath gas of the reactor, and a flow accumulator (D08-8C/ZM, Beijing Sevenstar
Electron Corporation) was used to record the total volume of the gas in the bag.
Chemicals
3-methyl-3-buten-2-one (TCI, 98%), 3-methyl-3-penten-2-one (Alfa Aesar, 95%), cyclohexane
(Alfa Aesar, 99+%), and dichlorosulfoxide (SOCl
Propene (1%, N as bath gas), 1-butene (1%, N as bath gas), O
CO ( 50.6×10 , N as bath gas) were supplied by National Institute of Metrology, China.
Experimental Methods
2
) (Alfa Aesar, 99+%) were used in this work.
2
2
2
(d＞99.999%), N (d＞99.999%),
2
-
6
2

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0
Cl atom reactions
The rate constants of MBO332 and MPO332 with Cl atom (k ) were determined by using a
K
3
6
relative rate method, similar to our previous works , in which the ketones and the reference
compounds reacted with Cl atom (reaction (1) and (2)) and the consumption of the reactants were
monitored synchronously.
k
K
9
9
1
2
ketones + Cl →products
(1)
(2)
k
R
reference +Cl →products
9
9
3
4
Where k and k were the rate constants for reactions (1) and (2) respectively. When combined
K R
and integrated the rate equations for reactions (1) and (2), we could get the following equation

CK ,0

 C

kK
R,0
9
5
ln
=
ln
(Ⅰ)








CK ,t
kR
CR,t




9
9
9
9
6
7
8
9
0
Where CK,0, CK,t, CR,0 and CR,t were the concentrations of ketones and references at time t and t,
respectively. Providing that the reactions of ketones and reference compounds with Cl atom were the
only removal processes and none of them were reformed in any process. Therefore, a plot of
ln(CK,0/CK,t) versus ln(CR,0/CR,t) should be a straight line passing through the origin with the slope of
1
1
1
1
1
1
1
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1
1
1
1
1
1
00
01
02
03
04
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08
09
10
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12
13
k
K
/k
R
. Then k
Dichlorosulfoxide (SOCl
situ photolysis of SOCl , with irradiation provided by the six UV fluorescent lamps with a maximum
K
can be obtained through multiplying the slope by the known value of k
R
.
2
) was used as a chlorine source, and Cl atoms were generated by in
2
3
7, 38
intensity at 254 nm
. Propene, 1-butene and cyclohexane were chosen as the reference
compounds because their Cl reaction rate constants were the same order of magnitude with the
expected rate constants of the studied unsaturated ketones.
2
The kinetic measurements were conducted in the air or N . The concentrations of the
unsaturated ketones and reference compounds were measured using a gas chromatograph equipped
with a flame ionization detector (GC/FID, GC6820, Agilent Technologies). Gas samples were
introduced via a 0.5mL Teflon loop mounted in a six way valve onto a DB-624capillary column (60
m length ×0.53 mm i.d., Agilent Technologies).
1
The initial concentrations of MBO332 and MPO332 were (6.15-12.30)×10 and
4
14
-3
(5.28-10.56)×10 moleculecm , respectively. Reference compounds were (6.16-12.78)×10
14
-3
15
-3
2
molecule cm and SOCl was (1.66-2.08)×10 molecule cm .

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O
3
reactions
The rate constants of the unsaturated ketones with O were determined using an absolute rate
3
3
4, 39
method
, in which the concentration of the unsaturated ketones was in large excess over that of
O
3
, and can be regarded as a constant throughout the reactions essentially. The temporal profile of O
3
was governed by the following processes.
k
K
1
1
19
20
ketones +O →products
(3)
(4)
3
k
0
wall +O →products
3
1
1
21
22
In all experiments, the following equation could be obtained under pseudo-first-order
conditions.
dln[O3]
dt
1
23
−
= k + k [ketones]
(Ⅱ)
0
K
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
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40
41
Where k
K
and k
0
were the rate constants for reactions (3) and (4). A plot of –dln [O3]/dt against
0 K K
[ketones] should be a straight line with k intercept and slope of k , then k could be obtained through
this linear plot.
O
3
was produced by flowing oxygen through an ozone generator (BGF-YQ, Beijing Ozone,
China) into the chamber. O concentration in the Teflon chamber was monitored by an ozone
3
analyzer (Model 49C, Thermo Electron Corporation, UV Photometric technology). Ketones were
introduced into the reactor followed by the addition of cyclohexane to scavenge any OH radical
formed during the reactions. Once O
analyzer and O concentration were collected over 10s time intervals.
The initial O concentration was in the range of (2.46-4.92) ×10 molecule cm , unsaturated
3
was introduced, the chamber was connected to the ozone
3
12
-3
3
13
-3
ketones concentrations were in the range of (2.64-18.45) ×10 molecule cm , and cyclohexane
15
-3
concentration was about 1.68×10 molecule cm .
Products analysis
The products experiments were carried out in the chamber similar to the one described above,
1
2
except for the absence of reference compounds. The initial reactants concentrations were 2.46×10
-3
molecule cm approximately. Reactants and products were detected in real time using the
proton-transfer-reaction mass spectrum (PTR-MS) (IoniconAnalytik, HS PTR-QMS 500). PTR-MS
-1
drift tube was operated at 2.2 mbar with a drift field of 600V cm , and the E/N was 133 Td. The

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temperatures of sample tube and drift tube were 60℃. Sampled air flow into the drift tube was
-1
-1
approximately 20 mL min , while the water vapor flow was 7 mL min .
+
O ) to chemically ionize the certain compound with a
The PTR-MS uses hydronium ions (H
3
proton affinity greater than that of water through an efficient proton transfer reaction. The protonated
organic ions can be detected based on mass to charge ratios (m/z) swiftly and sensitively.
Structurally different compounds with the same molecular weight cannot be distinguished from one
+
another, as compounds are identified by their molecular weight plus 1 (H ). However, because the
3
nature of chamber experiments is controlled in the laboratory, where one ketone reacted with O or
Cl atom at a time, the oxidation products will show increasing count rates with reaction time and can
be identified by the structure of the parent reactant through reasonable oxidation mechanisms. The
concentrations of compounds can be calibrated by the commercial standards or calculated using
known rate constants of the proton transfer reactions (See Electronic Supplementary Information for
calibration details of the PTR-MS).
Result and Discussion
Rate constants of unsaturated ketones with Cl atom and O
3
Cl atom reactions. Several control experiments concerning wall loss, photolysis and dark reactions
were performed before the kinetic measurements in order to verify the assumption that the reactants
were solely removed by the reactions with Cl atom. The mixtures of unsaturated ketones and
reference compounds were introduced into the chamber for the wall loss test in the absence of the Cl
atom precursor. Stable concentrations of the investigated compounds were monitored by GC-FID
through at least fifteen measurements over the course of 5 h, and the integrated peak areas decreased
were below 3% of their initial values. Then, the mixtures were subjected to photolysis for twice the
duration of each kinetic experiment without the Cl atom precursor. Moreover, Dark reactions were
2
carried out between the Cl atom precursor SOCl and mixtures of unsaturated ketones and reference
compounds for the duration of each kinetic experiment. On the basis of the above experiments, it was
found that the loss caused by wall loss, photolysis and dark reactions could be negligible compared
to the loss occurred on conversion of the unsaturated ketones and reference compounds in the same
time span of the Cl atom reaction experiments. The reproducibility of these measurements were
obtained in the range 1–4%, and could be considered to be good.
The reactions of Cl atom with unsaturated ketones and reference compounds were carried out

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00
01
individually to ensure the oxidation products do not interfere with the GC-FID measurements of
reactants. Therefore, propene, 1-butene and cyclohexane were used as reference compounds. The
typical logarithmic plots of the relative decrease in the form of Eq. (Ⅰ) for the reactions of Cl and
unsaturated ketones in the air are shown in Fig 1. As expected for relative rate plots, straight lines
with a zero intercept were obtained, indicating that the heterogeneous or secondary reactions were
insignificant. For each reference compound, the measurement was repeated for three times under
different initial concentration ratios of the ketones and reference compounds.
Fig1.
The rate constants ratio k
K R
/k and the obtained rate constants are summarized in Table 1. It
could be seen that O had no much effect on the kinetic measurements. The average rate constants
2
-10
-10
3
-1 -1
were (2.38±0.26) ×10 and (3.00±0.34) ×10 cm molecule s for MBO332 and MPO332, taken as
an average of all values. The listed errors consisted of twice the standard deviation from the
least-squares analysis of slope values and uncertainties of reference compounds rate constants.
Table 1.
O reactions. The loss of ozone for wall effect was also measured in the absence of ketones. The
3
-
6 -1
background ozone decay was a first order reaction, and could be calculated as k
0
=3.23×10 s ,
which was about two orders of magnitude lower than the pseudo-first-order reaction rate constants in
-4 -1
the range of (7.13-26.4)×10 s in this work. Therefore, the ozone loss caused by background decay
can be negligible.
Table 2
For each reaction investigated, five runs were conducted in the case of different initial ketone
concentrations. The details were shown in the Table 2. In every experiment run, the decay of O3
concentration was obtained as a function of time, and the decay rate of O
by the slope of straight-line plot of ln[O /[O against time (t-t ), as shown in Table 2 and Fig 2.
Then there were five decay rates of O related to different unsaturated ketones concentrations for
3 3
(-dln[O ]/dt) was yielded
]
3 0
3
]
t
0
3
each reaction investigated, and k
decay rates of O versus unsaturated ketones concentrations in the Fig 3. The rate constants for the
reactions of the unsaturated ketones with O
k
was obtained through linear least-squares analysis of the plot of
3
-
17
-17
3
obtained were (1.18±0.21) ×10 and (4.07±0.45) ×10
3 -1 -1
cm molecule s for MBO332 and MPO332, respectively. The errors given represented twice the
standard deviation from the least-squares analysis and about 10% of estimated systematic error.

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Fig 2.
Fig 3.
Table 3 presents the rate constants for the reactions of the unsaturated carbonyl compounds with Cl
atoms and O , as well as their parent alkenes. The terminal methyl groups in parent alkenes were
replaced by -C(O)CH , -C(O)OCH or –C(O)H to derive the carbonyl compounds. Intuitively, the
3
3
3
rate constants of MBO332 and MPO332 were found to be higher than those of 3-buten-2-one and
3-penten-2-one respectively, regardless of Cl reactions or O reactions. It could be seen that the
3
reactivity of the unsaturated ketones increased due to increasing substitution at the carbon-carbon
double bond by methyl group, which was likely caused by the electron-donating inductive effect of
3
3, 36, 40-43
the methyl group directly attached to the double bond
. Due to the substitution of methyl
group in 3-buten-2-one and 3-penten-2-one, the reactivity of MBO332 and MPO332 were increased
by factors of 1.21 and 2.02 for reactions with Cl atom. Similarly, the reactivity of MBO332 and
3
MPO332 were increased by factors of 1.15 and 1.40 in O reaction. The reactivity trend caused by
the substitution of methyl group was also applied to unsaturated esters and aldehydes, which could
be concluded from Table 3. The substitution of methyl group in methyl acrylate, methyl crotonate
and acrolein increased the reactivity of methyl methacrylate, methyl tiglate and methacrolein by
factors of 1.35, 1.04 and 1.13 in the Cl atom reactions, while the reactivity of methyl methacrylate,
methyl tiglate, methacrolein and trans-2-methyl-2-butenal were increased by factors of 7.17, 2.40,
3
4.15 and 3.38 in the O reactions. The factors were different between the unsaturated ketones, esters
and aldehydes, which reflected that the different functional groups attached to the carbon-carbon
double bond also played important role on the reactivity of the unsaturated carbonyl compounds.
Table 3.
Intuitively, the unsaturated carbonyl compounds were all less reactive toward Cl atom and O
3
than the corresponding alkenes expect the reaction of acrolein with Cl atom, as seen in Table 3. This
reduction in reactivity showed the deactivating effect of the carbonyl group attached to the double
bond toward electrophilic reactions. For Cl atom reactions, the electron withdrawing effect of the
carbonyl group would lower the electron density on the double bond, and the rate constants were
reduced by the carbonyl group influencing Cl atom addition reaction. It was revealed that the
addition process to the carbon-carbon double bond played an important role in the unsaturated
3
ketones-Cl reactions. While the unsaturated ketones reacted with O , they were mainly initiated by

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3
electrophilic addition of O to the double bond , so the electron withdrawing effect of the carbonyl
group was also operational. However, the reduction of reactivity in Cl atom and O reactions is
3
different for unsaturated ketones, esters and aldehydes.
4
5
The structure–activity relationships (SARs) developed by Atkinson made the relation of the
reactivity of a compound to its chemical structure for predicting the rate constant. The
group-reactivity factors were often used to estimate the reactivity of groups of related compounds
4
6, 47
that differ in their substitution concerning the reactions of unsaturated compounds
.
4
2
39
kSAR = kbasic C(xi )
∏
i=1
2
2
2
2
2
2
2
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2
2
2
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59
60
i
Where kbasic is the rate constant for the basic structure as the parent alkene mentioned above, and C(x )
were the group-reactivity factors that reflect the type of substituent attached to the double bond.
48
The group-reactivity factor for -CH was taken as unity . While the group-reactivity factors for
3
4
7
-C(O)CH
3
, -C(O)OCH
3
and -C(O)H for Cl atom reactions were calculated as 0.73, 0.74 and 0.87 ,
respectively, and those were 0.081±0.011, 0.070±0.017 for -C(O)CH
3
and -C(O)OCH in O
3
3
4
9
reactions . Then the experimental rate constants could be compared with the SAR calculated for
unsaturated carbonyl compounds, as shown in Fig 4.
Fig 4.
It can be seen that there was a good correlation between the experimental and the SAR calculated
rate constants for Cl atom reactions with an average ratio of kSAR/ kexp 1.18. However, the ratios of
k
SAR/ kexp had large changes, which were in the range of 0.085-0.82 in reactions of unsaturated
ketones with O , and in the range of 0.78-2.78 for reactions of unsaturated esters with O
Products of unsaturated ketones react with Cl atom and O3
3
3
.
Products identification. PTR-MS was used to identify the products of each reaction by analyzing
the mass to charge ratio (m/z) of the product fragments.
When irradiation started, the typical variations of concentrations of MBO332, MPO332 and
products for the reactions with Cl atom as a function of time are illustrated in Fig 5. The m/z 31 and
93 were found to be dominant products in the reaction of MBO332 with Cl atom, identified as
formaldehyde (HCHO) and chloroacetone (CH3C(O)CH2Cl). While in MPO332, m/z45 and 107
assigned to be acetaldehyde (CH3CHO) and CH
3
C(O)C(O)Cl were the primary species, and m/z 31
and 87 having high yields in MPO332 showed the presence of HCHO and butanedione

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2
2
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2
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81
82
83
84
85
86
87
88
89
90
(CH
3 3
C(O)C(O)CH ). Some products and patterns were consistently identified in the two reactions.
HC(O)Cl (m/z 54), CH C(O)Cl (m/z 79) and butanedione were observed in both reactions. Some
3
2 3 3 3
other products are detailed in the Table 3. CH =C(CH )C(O)CHO and CH CH=C(CH )C(O)CHO
from MBO332 and MPO332 showed decreases after they reached the peak (Fig 4 a-1 and b-1). We
inferred that they could have photodissociation reactions similar to methylglyoxal with irradiation
5
0, 51
provided by UV fluorescent lamps
.
Fig 5.
Table 4.
Fig 6 shows the time series of MBO332 and MPO332 ozonolysis in the presence of excess of
CO as OH radical scavenger. In MBO332, the m/z 87 and m/z 31 were the main products assigned to
CH
3 3
C(O)C(O)CH and HCHO, together with the m/z 33, m/z 47 and m/z 75 corresponding to
CH OH, formic acid (HCOOH) and formic anhydride (HC(O)OC(O)H) with yields of (3±0.4)%,
3
(10±1)% and (5±0.5)%, respectively. CH
dominant products of MPO332 ozonolysis, and HCHO, CH
(m/z 61) and (CHO)2 (m/z 59) as minor products. The signal at m/z 89 was observed by PTR-MS in
both O reactions, and tentatively assigned to CH C(O)COOH.
Fig 6.
Table 4 and Table 5 summarize the formation yields of products detected in the reactions of
MBO332 and MPO332 with Cl atom and O . The product yields were calculated as the initial slopes
3
C(O)C(O)CH
3
and CH
3
CHO were identified as the
3
OH, CH
2
C(O) (m/z 43), CH C(O)OH
3
3
3
3
between increased concentrations of the oxidation products and decreased concentrations of the
studied ketones using the least squares regression method. Errors presented in Table 4 and Table 5
are twice the standard deviation from the least-squares analysis of the slopes and uncertainties
estimated in the PTR-MS calibrations. In reactions of Cl atom with MBO332 or MPO332, count
2 3 3 3
rates of CH =C(CH )C(O)CHO and CH CH=C(CH )C(O)CHO decreased after reaching the peak
with time, so only the data before the peak were used for the least squares regressions. For different
products having the same m/z, a total yield was applied, as compounds having a same m/z are
indistinguishable by PTR-MS. For O
reactions with O could be neglected. Whereas, the products may react with Cl atom in Cl atom
reactions. The corrections were made to the product yields to take into account the loss due to the
3
reactions, the secondary consumption of products from
3
52
secondary reactions with Cl atom according to a method suggested by Atkinson et al (1982) . In the

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92
93
94
95
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01
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05
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11
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reaction of MBO332 with Cl atom, the correction factors were significant for formaldehyde, whereas
they were unimportant for chloroacetone. Taking into account the corrections, the yields of
formaldehyde and chloroacetone (including the Chlorine isotope effect) were 58±6% and 42±4%. In
the case of the reaction of MPO332 with Cl atom, the correction factors were important for
formaldehyde, acetaldehyde and methanol, and the yields with corrections were 47±5%, 58±6% and
3±0.2%, respectively.
Carbon balances of these reactions were all less than 1 and unclosed
were oxidation products underestimated owing to their very low sensitivity or not to be detected by
PTR-MS. It could be seen that CO and CO were important products in the Cl atom reactions from
the results obtained for methacrolein and methyl vinyl ketone . However, they were not detected by
PTR-MS in our experiments, which is the significant carbon loss. If adding the similar level CO , the
，which indicating that there
2
5
3
2
carbon balances of MBO332 and MPO332 may be comparable to the literatures data. In addition, the
products losing in the tubing or partitioning into the particle phase also affected the close of carbon
balance.
Table 5.
Reactions mechanisms. In order to discuss the results conveniently, the reasonable product
structures and formation mechanisms for the reactions of MBO332 with Cl atom and O
proposed in Scheme1 and 2 based on the products identified above, respectively.
MBO332 and MPO332 with Cl atom
3
were
MBO332 MBO332 reacted with Cl atom by addition to the carbon-carbon double bonds or H-atom
abstraction. The products of the suggested reaction pathways are CH C(O)C(O)CH (1), HC(O)Cl (2),
3
3
CH ClOH (3), CH C(O)CH Cl (4), HCHO (5), CH OH (6) from Cl addition at the terminal carbon,
2
3
2
3
CH
3
C(O)Cl (7), CH
3
C(O)C(O)Cl (8), CH
3
3 2 3 3
C(O)C(CH )ClCH OH (9) and CH C(O)C(CH )ClCHO
(10) from the C2 addition and C
The Cl atom addition pathway could be divided into two sub-pathways depending on the position of
the added Cl atom. The initial addition would be followed by reaction with O to form 1, 2- and 2,
5 8 2 5 6 2
H O (11), C H O (12) from H abstraction.
2
54
1-chloroxyalkyl peroxy radicals . In the present study, the1, 2- and 2, 1-chloroxyalkyl peroxy
radicals self-reactions would produce 1, 2- and 2, 1-chloroalkoxy radicals in the absence of NO,
respectively, while 2, 1-chloroxyalkyl peroxy radical also reacted with itself to form multifunctional
group compounds such as (9), (10). The alkoxy radicals were expected to react through four routes,

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3
3
3
3
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3
3
3
3
3
3
3
3
21
22
23
24
25
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30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
2
which included decomposition, reaction with O , isomerization through unimolecular or a
1
five-membered transition state . The present work identified the possible reaction channels of the
chloroalkoxy radicals. The formation of chloroacetone (4) showed the major fate of 1,
2-chloroalkoxy radicals, cleavage of the C2-C3 bond to form (4) with a yield of 29±3%, (5) and (6).
The (1) (2) and (3) could be obtained in small yields by the cleavage of C1-C2 bond of the same
53
radical. It was in consistent with the results obtained for MAC and MVK observed by Orlando et al .
The chloroacetone from MAC and chloroacetaldehyde from MVK were also main products from the
scission of C2-C3 bond of the 1,2-chloroalkoxy radical from the Cl addition to the terminal carbon.
5
3
Orlando et al have stated that elimination of CH
2 3
Cl would not compete with CH C(O) elimination
from the CH C(O)CH(O·)CH Cl radical in the MVK reaction, and methylglyoxal seems unlikely to
2
3
be produced. Similarly, the scission of C1-C2 bond of 1,2-chloroalkoxy radical in MBO332 reaction
also could be unimportant. For 2, 1-chloroalkoxy radicals, it could directly decompose to give
HCHO and chloroalkyl radicals, the latter decomposing into (7) or (8) in the presence of O
2
similar
to reaction pathways above, accompanied with the formation of HCHO or CH
of HCHO (5) can be up to (37±4)%.
3
OH. The total yields
5 8 2 5 6 2
H-abstraction reaction could happen on methyl of MBO332 to form C H O (11), C H O (12)
mentioned above, which were mixtures of the isomers. They were difficult to be distinguished from
one another by PTR-MS because of the isomers having the same m/z. The proposed structures are
given in Scheme1. Concerning the products yields mentioned in Table 3, it was indicated that Cl
atom addition reaction played a dominant role in reactions of unsaturated ketones with Cl atom,
especially Cl addition at the terminal carbon. While the H-abstraction process was of minor
importance.
Scheme 1.
MPO332 A similar reaction mechanism and scheme for the reaction of MPO332 with Cl atom could
be expected (see ESI scheme SI). The CH3CHO with a yield of 58±6% formed from the scission of
the C2-C3 bond bingding the alkoxy and carbonyl entities of the 3, 2-chloroalkoxy radical from the
Cl atom addition at the C3, accompanied with CH
The formation of CH C(O)C(O)CH show that cleavage of the C2-C3 bond of the 2, 3-chloroalkoxy
radical was operative and accounted for 11%, which was from the Cl atom addition at the C2. The
decomposition of this radical also resulted in the production of the HC(O)Cl, CH CHClOH, HCHO
3 3 3
C(O)Cl, CH C(O)C(O)Cl, HCHO and CH OH.
3
3
3

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79
80
and CH
3
6 10 2
OH. H-abstraction reaction could happen on methyl of MPO332 to form C H O and
C H O , which were also mixtures of the isomers.
5
6
2
It could be interesting to give comparison on the products formed from the reactions of MBO332 and
MPO332 with Cl atom and those obtained for other unsaturated ketones, aldehydes and esters.
53
Orlando et al have observed that chloroacetone as the main product with a yield of 42±5% formed
from scission of the C2-C3 bond binding the alkoxy and carbonyl entities of the 1,2-chloroalkoxy
radical from the Cl addition to the terminal carbon in methacrolein (MAC) oxidation process, and
HCHO with a yield of 18±2% was also observed. For methyl vinyl ketone (MVK),
chloroacetaldehyde and HCHO were the main products with yields of 75±8% and 47±7%, which
were also from scission of the C2-C3 bond of the 1,2-chloroalkoxy radical from the Cl addition to
the terminal carbon. However, Blanco et al. have observed that 1,2-chloroalkoxy radical formed in
the reaction of methyl methacrylate (MMA) could decompose to chloroacetone and HCHO with
yields of 41±6% and 35±5% by the scission of the C2-C3 bond, and HC(O)Cl and methyl pyruvate
from the cleavage of C1-C2 of the same radical were also observed with yields of 25±4% and
5
5
24±4% .
In the reaction of MBO332 with Cl atom, the main products were also from scission of the C2-C3
bond binding the alkoxy and carbonyl entities of the 1,2-chloroalkoxy radical from the Cl addition to
the terminal carbon, which was in consistent with the results obtained for MAC and MVK, but
contrasted with MMA. In the reaction of MPO332 with Cl atom, the products formed from the
decomposition of 3, 2-chloroalkoxy radical and 2, 3-chloroalkoxy radical due to the Cl atom addition
at the carbon-carbon double bond, which may result from the carbon-carbon double bond residing in
the middle of carbon chain of MPO332.
MBO332 and MPO332 with O
MBO332 The reaction of MBO332 with O
bond and then leaded to the formation of the primary ozonide, which could rapidly decompose by
3
3
3
proceeded by O electrophilic addition on the double
44
two channels , including (i) decomposing to give CH
[CH OO]*, and (ii) decomposing to give HCHO and Criegee intermediate [CH
The least squares regression analysis described above gave yields of 30±3% and 44±5% for
CH C(O)C(O)CH and HCHO, respectively. The both Criegee intermediates could undergo
collisional stabilization and react with various atmospheric trace gases. The excited forms were
3
C(O)C(O)CH
3
and the Criegee intermediate
2
3
C(O)C(CH )OO]*.
3
3
3

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01
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10
2
proposed to have a number of decomposition and/or rearrangement pathways. For [CH OO]*, it can
be stabilized, or decomposed to OH and some small molecules such as CO , CO. During the
2
reactions, HCOOH was formed in multiple reactions and detected in the experiments. Several
previous studies have indicated that formic anhydride (FAN) was produced in the decomposition of
hydroperoxy methyl formate (HPMF, HOOCH OCHO), a product of the reaction of stabilized
2
5
6, 57
CH
2
COO with HCOOH
. Normally the formation of FAN should be observed subsequently to
the formation of HPMF. However, HPMF (m/z 93) was not observed in our experiment under the
conditions of excess CO as OH scavenger. The formed FAN was possibly resulted from the reaction
58
of dioxirane with CO, as shown in scheme 2 .
Scheme 2.
MPO332 The primary ozonide rapidly decomposed to[CH
[CH C(O)C(CH )OO]* andCH CHO. The formation yields of CH C(O)C(O)CH and CH CHO
3
3 3
CHOO]*and CH C(O)C(O)CH ,
3
3
3
3
3
3
were 39±4% and 61±7%. [CH
CH OH etc. Moreover, it may lead to the corresponding carboxylic acid (CH
to the corresponding unsaturated hydroperoxide (CH =CHOOH), which form OH and an alkoxy
3
CHOO]* could directly decompose to OH radicals and HCHO,
3
3
C(O)OH), or rearrange
2
radical, which could undergo isomerization or decomposition to form CH
(m/z 59) and HCHO (see ESI scheme S2). CH OHCHO (m/z 61) had the same m/z as CH
and they cannot be distinguished by PTR-MS in this work.
Up to now, the fate of [CH C(O)C(CH )OO]* has not been elucidated, which was produced in
both MBO332 and MPO332 when reacted with O . Some possible reaction pathways of the Criegee
2
OHCHO (m/z 61), glyoxal
2
3
C(O)OH,
3
3
3
intermediate are given in scheme 2. The intermediate couldn’t generate OH radical in the
decomposition of the energy-rich hydropeoxide formed by isomerization, as there was no
observation of the products from the decomposition of the hydroperoxide. [CH
3 2
CH C(O)CHOO]*,
similar to the Criegee intermediate in this work, has been reported to lead to the carboxylic acid
59
CH CH C(O)COOH
3
. Therefore, it was possible for [CH C(O)C(CH )OO]* to form
3 3
2
CH
3
C(O)COOH, which may be demonstrated by the detection of the signal m/z 89 using PTR-MS.
and some other radicals,
A decomposition pathway may also happen to give the formations of CO
such as CH and CH C(O), which could lead to HCHO or CH OH.
Conclusion and Atmospheric implications
On the basis of rate constants obtained in this work, the atmospheric lifetimes of the unsaturated
2
3
3
3

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ketones with respect to reactions with Cl atoms and O
3
are calculated using the formula:τ=1/(k·[X]),
in which [X] represents the concentration of typical atmospheric oxidants (OH, NO , Cl and O ) and
3
3
k is the rate constant of the reactions between the oxidants and the considered ketones. The relative
importance of Cl atom and O
3
can be estimated compared to the reactions with OH and NO
3
radicals.
4
4
15
16
Table 5.
The tropospheric lifetimes for unsaturated ketones due to reaction with OH radicals are in the
range of a few hours and thus represent the dominant atmospheric sink process, indicating that these
compounds will be degraded close to their emission sources. Lifetimes of the ketones based on Cl
atom reactions are much longer than these based on OH radical. Nevertheless, in the marine
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
5
boundary layer and coastal areas, the peak concentration of Cl atom reaches as high as 10 molecule
-
3
cm in early morning, and then Cl based lifetimes turn to 11 h and 9 h for MBO332 and MPO332,
respectively. Cl atom reactions may have the potential to compete with OH-initiated reactions.
Therefore, Cl-initiated reactions may play an important role in the degradation of the studied ketones.
As mentioned in the introduction, recent field measurements have presented strong evidences for
ClNO
significant part in atmospheric chemistry than previously thought, although the distribution of these
sources remains to be established in the future. Similarly, the lifetimes due to O reactions would
turn to 8 h and 2 h for MBO332 and MPO332 respectively in some urban areas with elevated O
2
mediated Cl atom chemistry in continental regions. The Cl atom reactions may play a more
3
3
1
levels reaching up about 4.57×10 molecule cm
2
-3 60
. Therefore, the O reaction may be a
3
considerable homogeneous removal process for the studied ketones too.
3
In the light of our results, the reactions of unsaturated ketones with Cl atom and O mainly lead
to the formation of formaldehyde, acetaldehyde and chloroacetone, which are pollutants involved in
photochemical smog or health effect. And other highly oxygen-containing compounds such as
CH
3
C(O)C(O)Cl and butanedione may be expected to be precursors of organic aerosol. Moreover,
the chlorinated products are also the potential approach to be served as the specific chlorine atom
6
precursors in the Cl-initiated chemistry in the troposphere . To the best of our knowledge, this is
1
the first report on the kinetics and products analysis for the reactions of MBO332 and MPO332 with
3
Cl atom and O in the absence of NOx. However, under the conditions prevailing in the urban areas,
NOx will be involved in the oxidation reactions of unsaturated ketones. More information about the
products and mechanisms of these particular reactions has to be acquired based on different

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atmospheric conditions to evaluate their atmospheric importance.
Acknowledgments
This project was supported by the Strategic Priority Research Program（B）" of the Chinese Academy
of Sciences (Grant No. XDB05010400), National Basic Research Program of China (973 Program,
No. 2011CB403401) of Ministry of Science and Technology of China, and the National Natural
Science Foundation of China (Major Program: 21190052, Contract No. 21477134).
Reference
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
1.
2.
R. Atkinson and J. Arey, Chem. Rev., 2003, 103, 4605-4638.
P. Forster, V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D. W. Fahey, J. Haywood, J. Lean, D. C. Lowe and G.
Myhre, in Climate Change 2007. The Physical Science Basis, 2007.
3.
4.
M. Fry, M. Schwarzkopf, Z. Adelman and J. West, Atmos. Chem. Phys., 2014, 14, 523-535.
C. Scott, A. Rap, D. Spracklen, P. Forster, K. Carslaw, G. Mann, K. Pringle, N. Kivekäs, M. Kulmala and H.
Lihavainen, Atmos. Chem. Phys., 2014, 14, 447-470.
5.
6.
D. Grosjean, Quim. Nova, 1995, 18, 184-201.
A. Guenther, C. N. Hewitt, D. Erickson, R. Fall, C. Geron, T. Graedel, P. Harley, L. Klinger, M. Lerdau, W. A. McKay,
T. Pierce, B. Scholes, R. Steinbrecher, R. Tallamraju, J. Taylor and P. Zimmerman, J. Geophys. Res.-Atmos., 1995,
100, 8873-8892.
7.
M. Placet, C. O. Mann, R. O. Gilbert and M. J. Niefer, Atmos. Environ., 2000, 34, 2183-2204.
A. Mellouki, G. Le Bras and H. Sidebottom, Chem. Rev., 2003, 103, 5077-5096.
R. Atkinson, Atmos. Environ., 2000, 34, 2063-2101.
8.
9.
10.
A. C. Lewis, N. Carslaw, P. J. Marriott, R. M. Kinghorn, P. Morrison, A. L. Lee, K. D. Bartle and M. J. Pilling, Nature,
2000, 405, 778-781.
11.
12.
13.
M. Kanakidou, J. H. Seinfeld, S. N. Pandis, I. Barnes, F. J. Dentener, M. C. Facchini, R. Van Dingenen, B. Ervens, A.
Nenes, C. J. Nielsen, E. Swietlicki, J. P. Putaud, Y. Balkanski, S. Fuzzi, J. Horth, G. K. Moortgat, R. Winterhalter, C.
E. L. Myhre, K. Tsigaridis, E. Vignati, E. G. Stephanou and J. Wilson, Atmos. Chem. Phys., 2005, 5, 1053-1123.
S. K. Akagi, R. J. Yokelson, I. R. Burling, S. Meinardi, I. Simpson, D. R. Blake, G. R. McMeeking, A. Sullivan, T. Lee,
S. Kreidenweis, S. Urbanski, J. Reardon, D. W. T. Griffith, T. J. Johnson and D. R. Weise, Atmos. Chem. Phys., 2013,
13, 1141-1165.
J. D. McDonald, B. Zielinska, E. M. Fujita, J. C. Sagebiel, J. C. Chow and J. G. Watson, Environ. Sci.Technol ., 2000,
34, 2080-2091.
14.
15.
16.
17.
18.
19.
D. E. Seizinger and B. Dimitriades, J. Air Pollut. Contr. Assoc., 1972, 22, 47-51.
M. Dicke, Plant Cell Environ., 2009, 32, 654-665.
B. Davison, A. Brunner, C. Ammann, C. Spirig, M. Jocher and A. Neftel, Plant Biol., 2008, 10, 76-85.
K.-S. K. Rajendra Gyawali, Kathmandu Univ J Sci Eng Technol., 2012, 8, 51-62.
S. C. Xu, C. D. Wang, G. H. Sha, J. C. Xie and Z. Z. Yang, Theochem-J. Mol. Struct., 1999, 467, 85-93.
P. G. N. Mertens, H. Poelman, X. Ye, I. F. J. Vankelecom, P. A. Jacobs and D. E. De Vos, Catal. Today, 2007, 122,
352-360.
20.
21.
K. Bauer, D. Garbe and H. Surburg, Common fragrance and flavor materials, Wiley-VCH, Weinheim, 1997.
J. A. Thornton, J. P. Kercher, T. P. Riedel, N. L. Wagner, J. Cozic, J. S. Holloway, W. P. Dube, G. M. Wolfe, P. K.
Quinn, A. M. Middlebrook, B. Alexander and S. S. Brown, Nature, 2010, 464, 271-274.
H. D. Osthoff, J. M. Roberts, A. R. Ravishankara, E. J. Williams, B. M. Lerner, R. Sommariva, T. S. Bates, D.
22.

Page 17 of 26
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View Article Online
DOI: 10.1039/C4CP05461J
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Coffman, P. K. Quinn, J. E. Dibb, H. Stark, J. B. Burkholder, R. K. Talukdar, J. Meagher, F. C. Fehsenfeld and S. S.
Brown, Nat Geosci, 2008, 1, 324-328.
23.
24.
T. P. Riedel, T. H. Bertram, T. A. Crisp, E. J. Williams, B. M. Lerner, A. Vlasenko, S.-M. Li, J. Gilman, J. de Gouw, D.
M. Bon, N. L. Wagner, S. S. Brown and J. A. Thornton, Environ. Sci.Technol., 2012, 46, 10463-10470.
T. P. Riedel, N. L. Wagner, W. P. Dube, A. M. Middlebrook, C. J. Young, F. Ozturk, R. Bahreini, T. C. VandenBoer, D.
E. Wolfe, E. J. Williams, J. M. Roberts, S. S. Brown and J. A. Thornton, J. Geophys. Res.-Atmos., 2013, 118,
8702-8715.
25.
B. J. Finlayson-Pitts and J. N. Pitts Jr, Chemistry of the upper and lower atmosphere: theory, experiments, and
applications, Academic press, 1999.
26.
27.
28.
D. Johnson and G. Marston, Chem. Soc. Rev., 2008, 37, 699-716.
S. Y. Chang and D. T. Allen, Environ. Sci.Technol., 2006, 40, 251-262.
C. J. Young, R. A. Washenfelder, P. M. Edwards, D. D. Parrish, J. B. Gilman, W. C. Kuster, L. H. Mielke, H. D.
Osthoff, C. Tsai, O. Pikelnaya, J. Stutz, P. R. Veres, J. M. Roberts, S. Griffith, S. Dusanter, P. S. Stevens, J. Flynn, N.
Grossberg, B. Lefer, J. S. Holloway, J. Peischl, T. B. Ryerson, E. L. Atlas, D. R. Blake and S. S. Brown, Atmos. Chem.
Phys., 2014, 14, 3427-3440.
29.
30.
M. J. Ezell, W. H. Wang, A. A. Ezell, G. Soskin and B. J. Finlayson-Pitts, Phys. Chem. Chem. Phys., 2002, 4,
5813-5820.
C. W. Spicer, E. G. Chapman, B. J. Finlayson-Pitts, R. A. Plastridge, J. M. Hubbe, J. D. Fast and C. M. Berkowitz,
Nature, 1998, 394, 353-356.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
L. H. Mielke, A. Furgeson and H. D. Osthoff, Environ. Sci.Technol., 2011, 45, 8889-8896.
D. Grosjean and E. L. Williams, Atmos. Environ., 1992, 26(A), 1395-1405.
C. E. Canosa-Mas, M. L. Flugge, M. D. King and R. P. Wayne, Phys. Chem. Chem. Phys., 2005, 7, 643.
Y. Gai, M. Ge and W. Wang, Atmos. Environ., 2009, 43, 3467-3471.
L. Du, Y. Xu, M. Ge and L. Jia, Atmos. Environ., 2007, 41, 7434-7439.
Y. Gai, M. Ge and W. Wang, Atmos. Environ., 2011, 45, 53-59.
B. J. Finlayson-Pitts, C. J. Keoshian, B. Buehler and A. A. Ezell, Int. J. Chem. Kinet., 1999, 31, 491-499.
G. Baum, C. S. Effenhauser, P. Felder and J. R. Huber, J. Phys. Chem. A, 1992, 96, 756-764.
L. Du, Y. Xu, M. Ge, L. Jia, L. Yao and W. Wang, Chem. phys. lett., 2007, 436, 36-40.
F. Bernard, V. Daele, A. Mellouki and H. Sidebottom, J. Phys. Chem. A, 2012, 116, 6113-6126.
F. Bernard, G. Eyglunent, V. Daele and A. Mellouki, J. Phys. Chem. A, 2010, 114, 8376-8383.
C. E. Canosa-Mas, E. S. N. Cotter, J. Duffy, K. C. Thompson and R. P. Wayne, Phys. Chem. Chem. Phys., 2001, 3,
3075-3084.
43.
D. Rodriguez, A. Rodriguez, A. Soto, A. Aranda, Y. Diaz-de-Mera and A. Notario, J.Atmos.Chem., 2008, 59,
187-197.
44.
45.
46.
47.
48.
R. Atkinson and W. P. L. Carter, Chem. Rev., 1984, 84, 437-470.
R. Atkinson, J. Phys. Chem. Ref. Data, 1997, 26, 215-290.
E. Gaona Colmán, M. B. Blanco, I. Barnes and M. A. Teruel, Chem. phys. lett., 2013, 579, 11-15.
S. Hatakeyama, S. Honda and H. Akimoto, B Chem Soc Jap, 1985, 58, 2411-2412.
M. P. Martin Porrero, M. P. Gallego-Iniesta Garcia, J. L. Espinosa Ruiz, A. Tapia Valle, B. Cabanas Galan and M. S.
Salgado Munoz, Environ Sci Pollut Res Int, 2010, 17, 539-546.
49.
50.
51.
52.
J. Albaladejo, A. Notario, C. Cuevas, E. Jiménez, B. Cabanas and E. Martınez, Atmos. Environ., 2003, 37, 455-463.
T. A. Staffelbach, J. J. Orlando, G. S. Tyndall and J. G. Calvert, J. Geophys. Res.-Atmos., 1995, 100, 14189-14198.
S. Koch and G. K. Moortgat, J. Phys. Chem. A, 1998, 102, 9142-9153.
C. Pfrang, M. King, M. Braeckevelt, C. Canosamas and R. Wayne, Atmos. Environ., 2008, 42, 3018-3034.

Physical Chemistry Chemical Physics
Page 18 of 26
View Article Online
DOI: 10.1039/C4CP05461J
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
53.
54.
J. J. Orlando, G. S. Tyndall, E. C. Apel, D. D. Riemer and S. E. Paulson, Int. J. Chem. Kinet., 2003, 35, 334-353.
J. G. Calvert, R. Atkinson, J. Kerr, S. Madronich, G. Moortgat, T. Wallington and G. Yarwood, The mechanisms of
atmospheric oxidation of the alkenes, Oxford University Press New York, 2000.
55.
56.
57.
58.
59.
60.
M. B. Blanco, I. Bejan, I. Barnes, P. Wiesen and M. A. Teruel, Environ. Sci. Technol., 2014, 48, 1692-1699.
P. Neeb, O. Horie and G. K. Moortgat, Chem. phys. lett., 1995, 246, 150-156.
P. Neeb, O. Horie and G. K. Moortgat, J. Phys. Chem. A, 1998, 102, 6778-6785.
H. Kühne, S. Vaccani, T.-K. Ha, A. Bauder and H. H. Günthard, Chem. phys. lett., 1976, 38, 449-455.
E. Grosjean and D. Grosjean, J.Atmos.Chem., 1999, 32, 205-232.
T. Wang, W. Nie, J. Gao, L. K. Xue, X. M. Gao, X. F. Wang, J. Qiu, C. N. Poon, S. Meinardi, D. Blake, S. L. Wang, A. J.
Ding, F. H. Chai, Q. Z. Zhang and W. X. Wang, Atmos. Chem. Phys., 2010, 10, 7603-7615.
W. Wang and B. J. Finlayson‐Pitts, J. Geophys. Res.-Atmos,, 2001, 106, 4939-4958.
J. Stutz, M. J. Ezell, A. A. Ezell and B. J. Finlayson-Pitts, J. Phys. Chem. A, 1998, 102, 8510-8519.
W. H. Wang, M. J. Ezell, A. A. Ezell, G. Soskin and B. J. Finlayson, Phys. Chem. Chem. Phys., 2002, 4, 1824-1831.
R. Wegener, T. Brauers, R. Koppmann, S. R. Bares, F. Rohrer, R. Tillmann, A. Wahner, A. Hansel and A. Wisthaler,
J. Geophys. Res.-Atmos., 2007, 112, 17.
61.
62.
63.
64.
65.
S. Carr, D. E. Shallcross, C. E. Canosa-Mas, J. C. Wenger, H. W. Sidebottom, J. J. Treacy and R. P. Wayne, Phys.
Chem. Chem. Phys., 2003, 5, 3874-3883.
66.
67.
68.
69.
70.
71.
72.
73.
G. S. Tyndall, T. J. Wallington, M. D. Hurley and W. F. Schneider, J. Phys. Chem., 1993, 97, 1576-1582.
D. Grosjean, E. Grosjean and E. L. Williams, Int. J. Chem. Kinet., 1993, 25, 783-794.
P. Neeb and G. K. Moortgat, J. Phys. Chem. A, 1999, 103, 9003-9012.
M. B. Blanco, I. Barnes and P. Wiesen, J. Phys. Chem. A, 2012, 116, 6033-6040.
K. Sato, B. Klotz, T. Taketsugu and T. Takayanagi, Phys. Chem. Chem. Phys., 2004, 6, 3969-3976.
M. Witter, T. Berndt, O. Boge, F. Stratmann and J. Heintzenberg, Int. J. Chem. Kinet., 2002, 34, 394-403.
M. P. Gallego-Iniesta, B. Cabañas, S. Salgado, E. Martínez and P. Martín, Atmos. Environ., 2014, 90, 133-145.
O. W. Wingenter, M. K. Kubo, N. J. Blake, T. W. Smith, D. R. Blake and F. S. Rowland, J. Geophys. Res.-Atmos.,
1996, 101, 4331-4340.
5
5
5
5
5
5
5
5
52
53
54
55
56
57
58
59
5
5
60
61
Table 1. Summary of rate coefficient ratios k /k and rate coefficients for reactions of Cl atoms with
S R
2
unsaturated ketones in the air and N at room temperature and atmospheric pressure

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b
k
S
kK
a
VOCs
Reference
Propene
Carrier gas
air
k /k
K R
-
10
3
-1 -1
10 cm molecule s )
(
0.96±0.01
0.93±0.003
0.78±0.01
0.73±0.01
0.74±0.01
0.81±0.01
1.20±0.01
1.16±0.01
0.95±0.02
1.10±0.01
0.90±0.01
0.94±0.02
2.21±0.29
2.14±0.28
2.34±0.31
2.19±0.29
2.59±0.19
2.83±0.21
2.76±0.36
2.67±0.35
2.85±0.39
3.3±0.44
N
2
3
-methyl-3-buten-2-one
air
（
MBO332）
1
-Butene
2.38±0.26
N
2
air
Cyclohexane
Propene
N
2
air
N
2
3
-methyl-3-penten-2-one
MPO332)
air
(
1
-Butene
3.00±0.34
N
2
air
3.15±0.23
3.29±0.25
Cyclohexane
N
2
5
5
5
5
5
62
63
64
65
66
a.The errors represent 2σ.
b Rate coefficients at 298 K used for the reactions of Cl with propene, 1-butene, and cyclohexane were (2.3±0.3)×10 cm
-10
3
-
1
-1 62
-10
3
-1 -1 53
s
-10
3
-1 -1 45
s
molecule
s
, (3.0±0.4)×10 cm molecule
, and (3.5±0.25)×10 cm molecule
, respectively.
3
Table 2. The experimental conditions and results from the reactions of O with MBO332 and
MPO332 using the absolute method
[
ketone]
[O3]0
12
10 molecule cm
[cyclohexane]
15
10 molecule cm
-dln[O ]/dt
3
-4 -1
10 s
ketone
13
-3
-3
-3
1
0 molecule cm
6
9
.15±0.12
.23±0.18
2.78
3.02
3.68
3.22
2.89
1.68
1.68
1.68
1.68
1.68
7.13±0.01
11.0±0.04
14.5±0.03
18.2±0.05
21.5±0.04
3
-methyl-3-buten-2-one
12.3±0.24
15.4±0.30
(MBO332)
1
8.5±0.36
-
17
3
MBO332+O3=(1.18±0.21) ×10 cm molecule s
-1 -1
k
2
3
.69±0.09
.22±0.10
2.06
2.18
3.23
2.29
3.12
1.68
1.68
1.68
1.68
1.68
10.8±0.01
13.3±0.02
17.3±0.02
21.7±0.02
26.4±0.05
3
-methyl-3-penten-2-one
MPO332)
4.30±0.12
5.37±0.15
(
6
.44±0.18
-
17
3
MPO332+O3=(4.07±0.45) ×10 cm molecule s
-1 -1
k
5
5
67
68
Table 3. Rate constants for the gas-phase reaction of unsaturated carbonyl compounds with Cl atom
and O3 and their parent alkenes.

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DOI: 10.1039/C4CP05461J
3 -1 -1
(cm molecule s )
3 -1 -1
k (cm molecule s )
Unsaturated
ketones
k
Parent alkenes
1-propene
1
Cl atom(10 )
0
18
3
10
Cl atom(10 )
17
3
O (10 )
O (10 )
3
-buten-2-one
=CHC(O)CH
methyl acrylate
63
65
63
59
66
67
a
1
1
2
.95±0.52
.71±0.13
.53±0.72
5.84±0.39
0.95±0.07
0.26±0.05
CH
2
3
62
64
2.30±0.30
1.06±0.12
CH
2
=CHC(O)OCH
3
acrolein
CH
-methyl-3-buten-2-one
CH =C(CH )C(O)CH
2
=CHCHO
3
a
2
.38±0.26
11.8±2.10
2
3
3
methyl methacrylate
CH =C(CH )C(O)OCH
methacrolein
CH =C(CH )CHO
-penten-2-one
CH=CHC(O)CH
methyl crotonate
6
5
3
0
5
3
66
29
68
2
2
2
2
3
.30±0.18
.86±0.76
.53±0.54
.21±0.17
.16±0.93
6.70±0.90
1.08±0.20
29.5±4.10
4.38±0.30
1.58±0.23
isobutene
3.40±0.28
1.24±0.08
2
3
3
6
7
6
6
59
70
67
70
a
2
3
3
CH
3
3
29
64
(E)-2-butene
3.31±0.47
23.8±1.5
CH CH=CHC(O)OCH
3
3
crotonaldehyde
CH CH=CHCHO
3
3
-methyl-3-penten-2-one
a
3
.00±0.34
40.7±4.50
CH
CH=C(CH )C(O)CH
3 3
3
methyl tiglate
72
72
29
71
2
.92
/
10.5
2-methyl-2-butene
3.95±0.32
41.0±5.0
CH
3
CH=C(CH )C(O)OCH
3 3
trans-2-methyl-2-butenal
CH CH=C(CH )CHO
This work
70
5.34±0.73
3
3
5
5
69
70
a
.
Table 4. Formation yields of products during experiments of MBO332 and MPO332 with Cl atom
Products of MBO332+Cl
HCHO
Yield (%)
Products of MPO332+Cl
CH CHO
Yield (%)
b
b
58±6
3
58±6
c
Chloroacetone
42±4
CH C(O)C(O)Cl
3
14±2
b
2
,3-Butanedione
CH OH
3±0.32
2±0.22
1±0.11
HCHO
47±5
3
2,3-Butanedione
CH OH
11±2
b
HC(O)Cl
3
3±0.2
CH ClOH
2
≈
≈
≈
0.2
0.4
0.4
CH C(O)Cl
3
≈
0.4
1±0.14
0.2
CH
3
C(O)C(O)Cl
C(O)Cl
=C(CH )C(O)CHO
HC(O)Cl
CH
3
CH
3
CHClOH
≈
a
a
CH
2
3
4±0.3
CH CH=C(CH
3
3
)C(O)CHO
3±0.5

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a
a
CH
2
=C(CH )C(O)CH
3
2
OH
3±0.2
0.2
0.07
48±5
CH
3
CH=C(CH )C(O)CH
3
2
OH
≈0.8
CH C(O)CCl(CH )CHO
3
≈
3
CH
3
C(O)CCl(CH
3
)CH
2
OH
≈
Carbon balance (%)
Carbon balance (%)
46±6
a
5
5
5
5
5
71
72
73
74
75
The yields included mixtures of the isomers
b
The yields including the corrections from secondary reaction with Cl atom
c
The yields including the corrections from secondary reaction with Cl atom and the the Chlorine isotope effect
Table 5. Formation yields of products during experiments of MBO332 and MPO332 ozonolysis in
the presence of excess CO
Products of MBO332+O
3
Yield (%)
44±5
Products of MPO332+O
3
Yield (%)
61±7
HCHO
CH CHO
3
2
,3-Butanedione
HCOOH
30±3
2,3-Butanedione
HCHO
39±4
10±1
15±2
CH OH
3
3±0.4
5±0.5
<0.01
CH
CH
Glyoxal
OHCCH OH
3
OH
3±0.5
a
Formic anhydride
pyruvic acid
2
CO
21±2
5±1
b
2
7±1
pyruvic acid
1±0.2
61±7
Carbon balance (%)
38±4
Carbon balance (%)
a
5
5
5
5
76
77
78
79
included the signal of OHCCH
2
OH (m/z 61) eliminating one H O molecule
2
b
3
included the signal of CH C(O)OH (m/z 61)
Table 6. Summary of rate constants and estimated atmospheric chemical lifetimes
τ
for the reactions
of unsaturated ketones with OH, NO
3 3
, Cl, and O .
3
k(cm molecule s )
-1 -1
Molecule
τ
(h)
11
17
O3×10
15
10
k
OH×10
k
k
NO3×10
k
Cl×10
τOH(h)
τ
O3(h)
τNO3(h)
τCl(h)
b
c
d
c
3
-methyl-3-buten-2-one
3.60
1.18
8.27
2.38
3.86 33.63 67.18 116.71
(
MBO332)
-methyl-3-penten-2-one
MPO332)
b
c
d
c
3
4.20
4.07
155
3.00
3.31
9.75
3.58
92.59
(
a
6
and Cl used in the calculations are 2×10 molecules cm , 5×10 molecules cm , 7×10
-3
8
-3
11
5
5
5
5
5
80
81
82
83
84
The concentrations of OH, NO
3
, O
3
-
molecules cm , and 1.0×10 molecules cm , , respectively.
39
4
-3 73
b
32
Rate coefficients of OH radical reactions
c
Rate coefficients of O and Cl atom reactions: This work.
3
d
33
3
Rate coefficients of NO radical reactions
5
5
85
86
Figure captions

Physical Chemistry Chemical Physics
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5
5
5
5
5
5
5
5
5
5
5
87
88
89
90
91
92
93
94
95
96
97
Fig 1. Relative loss of MBO332 and MPO332 versus reference compounds in presence of Cl atoms
3
Fig 2. Pseudo-first-order plots for O reactions with different concentrations of (a) MBO332 and (b)
MPO332
3
Fig 3. Plots of –dln[O ]/dt versus ketones concentrations
Fig 4. Comparisons of the experimental and SAR calculated rate constants for reactions of
unsaturated carbonyl compounds with Cl atom and O3.
Fig 5. Reaction products of Cl atom with (a) MBO332 and (b) MPO332
3
Fig 6. Products for O reactions with (a) MBO332 and (b) MPO332
Scheme 1. Proposed Reaction pathways for the reaction of MBO332 with Cl atom
Scheme 2. Proposed reaction pathways of MBO332 with O3
5
5
98
99
Fig 1. Relative loss of MBO332 and MPO332 versus reference compounds in presence of Cl atoms
6
00
6
6
01
02
Fig 2. Pseudo-first-order plots for O
3
reactions with different concentrations of (a) MBO332 and (b)
MPO332
6
03

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6
6
04
05
3
Fig 3. Plots of –dln [O ]/dt versus ketones concentrations
6
6
06
07
Fig 4. Comparisons of the experimental and SAR calculated rate constants for reactions of
unsaturated carbonyl compounds with Cl atom and O
6
08
3
.
6
6
09
10
Fig 5. Reaction products of Cl atom with (a) MBO332 and (b) MPO332

Physical Chemistry Chemical Physics
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6
6
11
12
3
Fig 6. Products for O reactions with (a) MBO332 and (b) MPO332

Page 25 of 26
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6
6
13
14
Scheme 1. Proposed reaction pathways for the reaction of MBO332 with Cl atom

Physical Chemistry Chemical Physics
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6
6
15
16
Scheme 2. Proposed reaction pathways of MBO332 with O
3