ENVIRONMENTAfc
PROTECTION
AGENCY
DALLAS, TEXAS
EPA-600/3-76-024
March 1876 Ecological KeseardbfiJMftY
AN INVESTIGATION OF
GAS PHASE OZONOLYSIS REACTIONS
Environmental Sciences Research Laboratory
Office of Research and Development
JLS, Environmental Protection Agency
Research Triangle Park, North Caroiina 27711
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RESEARCH REPORTING SERIES
Research ieports of the Ottu r-01 Researcr ana Development US Environmental
Protection Agency have Dren giouped into fivf senes These five broaa
categories were established ic facilitate further development and application of
environmental technologv E.irnm'ation o: tracitiona: grouping was consciously
plot fi iL-G tw t^oto. iCoJ pjL/i ^/^ y i.a'.oftri <3i /^ d .;/<3AM ,< i.ji j < M'it^iicJuc; ill icidleu
Trie five series are
1 Environmental Health Eftects Research
2 Environments. Protection Tecnnoiogy
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
This report has been assigned to the ECOLOGICAL RESEARCH series This series
describes research on tne effects of pollution o^ numans plant and animal
species, and materials Problems aie assessed for their long- and short-term
influences Investigations include formation transport and pathway studies to
determine the fate of pollutants and their effects Thus worn provides the technical
basis for setting standards to minimize undesirable changes in living organisms
in tne aguatic, terrestrial, and atmospheric environments
This document is available to the public through the National Technical Informa-
tion Service. Springfield Virginia 22161
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EPA-600/3-76-024
March 1976
AN INVESTIGATION OF GAS PHASE OZONOLYSIS REACTIONS
David G. Williamson
Chemistry Department
California Polytechnic State University
San Luis Obispo, CA 93407
Grant No. R-900984
Project Officer
Joseph J. Bufalini
Atmospheric Chemistry and Physics Division
Environmental Sciences Research Laboratory
Research Triangle Park, North Carolina 27711
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL SCIENCES RESEARCH LABORATORY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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DISCLAIMER
This report has been reviewed by the Environmental Sciences
Research Laboratory, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U.S. Environmental
Protection Agency, nor does mention of trade names or commercial pro-
ducts constitute endorsement or recommendation for use.
ii
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CONTENTS
List of Figures iv
List of Tables v
I. Summary and Conclusions 1
II. Experimental Methods 5
III. Results and Discussion 11
1. Stoichiometry of some ozone-olefin reactions 11
2. Rates of ozone-olefin reactions 21
3. Measurements of light scattering by aerosols in the
reaction of trans-2-butene with ozone 40
IV. References 46
iii
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LIST OF FIGURES
Page
Figure 1. Schematic of Apparatus 6
Figure 2. Diagram of Reaction Cell 7
Figure 3. n vs. (Ethylene)0/(03)0 16
Figure 4. n vs. (Propene)0/(03)0 17
Figure 5. n vs. (l-Butene)0/(03)0 18
Figure 6. n vs. (Cis-2-Butene)0/(03)0 19
Figure 7. n vs. (Methylpropene)0/(03)0 20
Figure 8. Second Order Plot. Ethylene + Ozone 23
Figure 9. Second Order Plot. Propene + Ozone 24
Figure 10. Second Order Plot. 1-Butene + Ozone 25
Figure 11. Second Order Plot. Methylpropene + Ozone 26
Figure 12. Second Order Plot. Trans-2-Butene + Ozone .... 32
Figure 13. Second Order Plot. Cis-2-Butene + Ozone 33
Figure 14. Second Order Plot. Trans-2-Butene + Ozone.
High Concentration 34
Figure 15. Test for Inhibition of 03 Decomposition 35
Figure 16a. Infrared Spectrum of the Aerosol from the Trans-2-
Butene + Ozone Reaction 38
Figure 16b. Infrared Spectrum of the Aerosol from the Trans-2-
Butene + Ozone Reaction 39
Figure 17. Intensity of Scattered Light vs. Time in the Trans-2-
Butene + Ozone Reaction 42
Figure 18. Maximum Intensity of Scattered Light vs. Concentration
of Trans-2-Butene 43
i v
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LIST OF TABLES
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Page
A Summary of Some Rate Constants for Ozone-Olefin
Reactions 2
A Summary of the Rate Constants for Ozone-Olefin
Reactions as Determined in this Study 3
The Stoichiometry of Some Ozone-Olefin Reactions . . . .12
Apparent Second Order Rate Constants for Some Ozone-
Olefin Reactions 27-28
Apparent Second Order Rate Constants for the Reaction
of Trans-2-butene and Cis-2-butene with Ozone . . .
Results of Light Scattering Experiments for the
Ozone + Trans-2-butene Reaction
. 31
Light Scattering in the Ethylene + Ozone Reaction
. 41
. 44
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SECTION I
SUMMARY AND CONCLUSIONS
This study was primarily designed to resolve the discrepancies which
exist in the values of the second order rate constants for various ozone-olefin
reactions. A brief summary of rate constants for some reported ozone olefin
reactions, as adapted from references [2, 7], is shown in Table 1. The largest
discrepancies in the second order rate constants shown in Table 1 are in the
cases of cis and trans-2-butene.
A gas phase stopped-flow system was used to measure the rates and
stoichiometry for the reactions of ozone with the above mentioned olefins. The
stoichiometry for the reaction of ethylene, 1-butene, and methylpropene was
found to depend on the ratio of initial concentrations (olefin)0/(03)0. As
this ratio increases the value of moles olefin used/moles ozone used, symbol-
ized by n, increases. This suggests that the initial reactants are not only
consumed by a bimolecular process between olefin and ozone, but secondary
reactions are depleting the initial reactants as well. Therefore, the measured
rate constants may not be simple bimolecular rate constants, but are probably
more complex apparent second order rate constants.
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TABLE 1
A SUMMARY OF SOME RATE CONSTANTS
FOR SOME OZONE-OLEFIN REACTIONS
(olefin)n
^3 x 10~7
^5 x TO'7
•v8 x 10-7
*1 x IQ-1*
M x TO"3
'v.l x 10'3
^3 x TO'7
^5 x TO"7
^2 x 10~6
*1 x 10-3
M x TO'3
M x ID"3
1 x 10'8
<\,2 x 10-8
*1 x TO'3
*A x TO'8
^1 X TO'3
^4 x 10~8
-vl X ID"3
^4 x 10'8
M x ID"3
(03)n
{Ethyl ene)
'v.l X 10~7
%5 x 10~7
^8 x ID"7
^2 x 10~5
^2 x 10-^
^2 x TO'1*
(Propene)
•v.5 x 10'8
%5 x TO'7
^3 x TO'7
^2 x 10-^
•v2 x TO'4
^2 x ID'1*
(Trans-2-butene)
1 x lO'8
•v-2 x TO'8
^2 x 10-^
(Cis-2-butene)
^4 x 10-8
^2 x 10-1*
(1-Butene)
^4 x ID"8
^2 x lO'4
Methyl propene
^4 x 10'8
^2 x TO'1*
1.6 x 103
0.9 x 103
0.78 x 103
1.8 x 103
2.4 x 103
1.6 x 103
3.7 x 103
8 x 103
4.8 x 103
6.7 x 103
6.4 x 103
5.5 x 103
2.6 x 105
1.6 x 105
2. x 101*
2. x 105
1.3 x 10^
6 x 103
4 x 103
1.4 x 10^
3.6 x TO1*
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The ozone-olefin reactions studied followed second order kinetics and
the apparent second order rate constants were determined and are summarized
in Table 2.
TABLE 2
A SUMMARY OF THE RATE CONSTANTS FOR OZONE-OLEFIN REACTIONS
AS DETERMINED IN THIS STUDY
Initial Reactant Concentration (moles/1,) Value of the Rate Constant Umole"1sec"1)
(olefin)n (Q3)0
Ethylene + Ozone
5 x 10-5 1 x 10'5 0.8 x 103
1 x 10-5 0.3 x 10-5 0.9 x 103
0.1 x 10-5 0.1 x 10-5 1.5 x 103
Propene + Ozone
5 x lO"5
3 x 10-5
1 x 10'5
4 x 10~5
1 x TO"5
0.1 x 10-5
1 x 10'5
1 x 10'5
0.75 x TO"5
1-Butene
1 x 10-5
0.1 x TO"5
0.1 x 10-5
+ Ozone
Methylpropene + Ozone
5 x 103
6 x 103
7 x 103
6 x 103
6 x 103
7 x 103
5 x ID'5 1 x 10~5 8 x 103
2 x 10-5 1 x 10-5 10 x 103
1 x 10-5 1 x 10-5 8 x 103
Trans-2-butene + Ozone
.16 x 10~5 .06 x 10~5 85 x 103
0.1 x 10~5 0.1 x 10~5 120 xlO3
Cis-2-butene + Ozone
0.2 x 10~5 0.1 x 10~5 73 x 103
0.04 x TO'5 0.04 x TO'5 130 x 103
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For olefins other than methylpropene the values of the apparent
second order rate constants appear to increase as the initial concentration
of olefin is decreased, which again suggests that the measured rate constant
is not a simple bimolecular rate constant for the olefin-ozone reaction.
Formation of significant amounts of aerosol in the reaction of cis or trans-
2-butene at concentrations of olefin greater than about 0.5 x 10~5 mole/£
prevented accurate determination of the rate constants at olefin concentra-
tions higher than 0.5 x 10~5 mole/£. It is thought that the formation of
aerosols produces complications at concentrations of olefins greater than
5 x 10~6 mole/s, in the measurements of the rate constants for the cis and
trans-2-butene and may be the reason for the discrepancies in the reported
values of the rate constants for these two olefins.
Aerosols were generated in the reactions with ozone of each of the
olefins studied. The intensity of scattered light as a function of olefin
concentration and reaction time were measured for trans-2-butene and ethylene.
An induction period between the time the reaction is started and the first
scattered light can be measured was observed for both olefins. This induction
period is a strong function of the concentration of olefin as is also the
maximum intensity of scattered light.
Future experiments using the stopped-flow method should include:
1. Rate measurements down to about 5 x 10~8 mo1e/£ concentrations using a
longer path length cell
2. Careful measurement to determine the effect or 62 concentration on the
apparent rate constants and reaction stoichiometry
3. Determination of the product distribution in the cis and trans-2-butene
reactions at high (c.a. ^lO"1* mole/£) and low (c.a. ^1Q~7 mole/a) concen-
trations
4. Characterization of aerosol composition.
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SECTION II
EXPERIMENTAL METHODS
This investigation was initiated in order to resolve the discrepancies
in the published values of the second order rate constants for ozone-olefin
reactions. Rate constants were to be measured over large concentration ranges
of reactants using the same experimental method.
The experimental apparatus for measurement of reaction rates is shown
in Figure 1. Figure 2 shows the reaction cell which is constructed of Pyrex
glass, except for the front and rear windows which are of quartz. The quartz
windows are joined to the Pyrex cell with a small amount of Torr Seal cement.
The four-way valve is also Pyrex and is lubricated with a small amount of
silicone stopcock grease.
Gas flows were measured with rotameters which were previously calibrated
using either a wet test meter or a soap bubble meter. The calibration curve
for the 1% (by volume) olefin in nitrogen mixture was assumed to be the same
as the calibration curve for pure N2. Some typical gas flows in an experiment
would be 35 liters/minute for N2, 0.15 liter/minute for the 02 + 03 mixture,
and 0.10 liter/minute for the 1% olefin in N2 mixture. By adjusting the flow
rates the concentrations of the olefin and 03 could be varied. Conditions for
turbulent flow of gases, which should facilitate mixing of the reactant gases,
existed in the 4 mm I.D. tubing that leads to the reaction vessel. Typical
total pressures in the reaction cell are 770 torr to 800 torr.
The photometric system for measuring the ozone concentration consisted
of a low pressure Hg lamp (Pen Ray), an adjustable slit, two quartz lenses about
2 focal lengths apart to collimate the light beam, another slit, the quartz
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Figure 1. Schematic of Apparatus
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03 + 02
V* k 1
T
5.0
cm
i
pressure
gage
Side View
Front surface, coated aluminized flat mirrors
1P28A
PhotomuUiplier
Top View
Collinated
light beam
Figure 2. Diagram of Reaction Cell
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windows of the cell, two front surfaced aluminized mirrors, an interference
filter, and finally a RCA 1P28A photomultiplier tube. With the aid of a He-Ne
laser the mirrors could be adjusted to give either 1, 3, or 5 traverses through
the cell so that a light path length of 100. cm could easily be attained with
the 20 cm long cell. The photomultiplier was housed in a box designed such
that the only light which could strike the photocathode was the light which
passed through the interference filter. The filter has a maximum of 15% trans-
mission at 2500 A and a one half band width of 125 A. Signal from stray light
other than that of about 2500 A amounted to no more than 0.5% of the total
signal measured. The Hg resonance line emission at 2537 A i< at a well-defined
wavelength and the light intensity measured with the photomultiplier should
be monochromatic light at 2537 A wavelength.
The current generated by the photomultiplier passed through a load
resistor. The voltage drop across this resistor was measured with a potentio-
metric strip chart recorder. Conditions in the photomultiplier circuit were
such that the current going through the load resistor was much less than 1%
of the current going through the dynode voltage divider circuit. Therefore
the photocurrent generated should be directly proportional to the light inten-
sity striking the photocathode.
The ozone generator was constructed from two concentric glass tubes.
The inner tube contained an electrolyte (6 N H^OiJ and the outer tube was
covered with metal foil and insulated. Oxygen gas flowed between the tubes
and a voltage of about 15,000 volts was applied between the tubes to generate
sufficient quantities of ozone for the experiments. After allowing for a
half-hour warm up, the 03 concentration in the effluent 03 - 02 mixture was
quite constant and changed no more than ±2% within a time interval of two hours.
In a typical experiment the gas flow rates are adjusted to the desired
values with the four-way stopcock turned such that the mixed gases flow through
-------
the reaction cell. After about two minutes the ozone concentration reaches a
steady state (as measured photometrically). Ther the flow through the cell is
stopped by rotation of the four-way valve. Pressure inside the cell is mea-
sured with a mercury free diaphragm gage. The percent transmission of the
reaction mixture is then measured as a function of time with the strip chart
recorder. Ozone concentrations at different reaction times can be easily
calculated from the optical density (or absorbance).
The extinction coefficient of 03 at 2537 A (e) was determined using
three traversals of light and five traversals of light through the reaction
cell. By passing the ozonized oxygen at a known flow rate through a KI trap
and then titrating the triiodide ion generated with standardized sodium thio-
sulfate, it was possible to calculate the concentration of 03 in the oxygen.
A typical concentration of 03 in the 02 would be between 1 and 5 x 10"1* moles/
liter. The concentration in the 02 could be varied by changing the voltage on
the primary of the ozonizer transformer. The ozonized oxygen stream was diluted
in the mixing chamber with nitrogen gas. By knowing the flow rates of the
ozonized oxygen and the diluting nitrogen the concentration of 03 in the cell
could be calculated. The photometric measurement of I/IQ, where I is the light
intensity passing through the cell with the 03, 02, N2 mixture in the cell and
IQ is the light intensity getting through the cell with no 03 present, permits
the value of e in Equation I to be calculated.
logio \~T~) ~ £CI (I)
Quantities C and I are respectively the reaction cell ozone concentration in
moles per liter, and the path length of the cell. The extinction coefficient
e was calculated to be 2755± 100 liter mole^cnr1. This value is in excellent
agreement with the value determined by Johnston at 2537 A (5). Equation (I)
-------
v;as obeyed to the limits of photometric accuracy and the accuracy to which the
gas flow rates could be measured. The combined error would be about 5%.
To determine the stoichiometry of ozone-olefin reactions, the ozone
concentration was measured photometrically as already described and the olefin
concentration was measured using a Varian Model 600 D gas chromatograph equipped
with a flame ionization detector and a 5% SE-30 on Chromasorb P 100/120 mesh
6 ft. long 1/8 in. diameter copper column. The gas chromatograph was calibrated
using olefin-N2 gas mixtures of known composition. By measuring the ozone and
olefin concentration before and after completion of the chemical reaction, the
amounts of each reactant consumed by the reaction could be calculated.
Scattered light intensities produced by aerosols were measured by
using the beam (6328 A wavelength) from a 0.5 mw He-Ne laser directed along a
path roughly parallel to the longitudinal axis of the cylindrical reaction
vessel. An RCA 1P22 photomultiplier tube was mounted perpendicular to the
laser beam and was used to moniter the intensity of the scattered laser light
as a function of time. To ensure that the light being measured by the 1P22
photomultiplier was the same wavelength as the light incident on the cell, a
blackened box was built around the reaction vessel, and an interference filter
0 r>
with a half band width of 100 A at 6328 A was placed between the photomultipliir
and the reaction vessel. (To further minimize interference from stray light,
the scattering measurements were done in a dark room.) The signal from the
photomultiplier was amplified with a Gencom Model 1012 picoammeter and the
voltage output was measured with a stripchart recorder.
All olefins used were Matheson C.P. grade gases which were no less
than 99.0% pure. Matheson high purity nitrogen (99.99%) was used in the pre-
paration of the gas mixtures and for the diluting gas in the stopped flow
experiments. Ozone was generated by passing Matheson Extra Dry (99.6%) oxygen
through the ozonizer.
10
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SECTION III
RESULTS AND DISCUSSION
1. Stoichiometry of some ozone-olefin reactions
The values of moles olefin used/moles ozone used, symbolized by the
letter "n", are compiled for some olefins in Table 3. The stoichiometric
determinations were made with a 1.0 cm diameter by 20.0 cm long Pyrex reaction
cell with quartz windows fastened on each end with Varian Torr Seal epoxy.
Typical experimental conditions were:
gas gas_ f 1 ow rate ( /mi n )
1% olefin in N2 0.8
M 03 in 02 0.6
N2 8.
Temperature = 25 ± 2°C
Total gas pressure in cell = 770 torr
The symbols (olefin)0 and (Oa) refer to the initial olefin and ozone concen
trations respectively. Both concentrations are expressed in moles/liter.
11
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TABLE 3
THE STOICHIOMETRY OF SOME OZONE-OLEFIN REACTIONS
Ethylene + Ozone
(Olefin)oxlO5 (Q3)nx105 (01efin)o/(03)n n
0.775 1.32 0.59 0.84
2.39 1.30 1.84 1.00
4.00 1.25 3.20 1.25
3.55 1.20 2.96 1.20
5.35 1.17 4.57 1.28
Propene + Ozone
(Olefin)nxl05 (03)nXlQ5 (01efin)n/(0a)(
2.04 2.08 0.981
1.41 2.21 0.516
1.56 2.11 0.739
2.36 2.04 1.16
0.712 0.897 0.794
0.353 1.03 0.343
0.353 0.987 0.358
0.579 1.41 0.410
0.574 1.42 0.410
1.33 1.36 0.979
0.952 1.37 0.695
0.433 1.45 0.30
0.615 1.42 0.433
1.17 1.39 0.842
0.421 1.47 0.286
1.13 1.39 0.813
1.36 2.10 0.648
0.944 2.30 0.411
1.41 2.01 0.704
1.87 2.05 0.91
0.747 1.85 0.404
4.75 1.20 3.96
3.42 1.21 2.83
1.69 1.31 1.29
4.18 1.22 3.43
12
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TABLE 3. Cont.
1-Butene + Ozone
(01ef1n)nx105 (0^)nx105 (01efinr/(03)o n
2.06 " 2.06 1.00 1.14
1.01 1.37 0.737 1.13
1.39 1.38 1.01 1.22
1.27 1.36 0.930 1.10
0.767 1.36 0.564 1.13
0.385 1.41 0.273 1.01
2.47 1.15 2.15 1.18
2.47 1.25 1.98 1.03
2.47 1.21 2.04 1.13
1.86 1.25 1.49 1.07
3.92 1.13 3.47 1.23
5.46 1.12 4.88 1.39
2.82 1.28 2.20 1.09
5.46 1.07 5.10 1.28
5.46 1.12 4.88 1.37
0.297 1.34 0.222 1.01
n
(O^)oxlO5 (Olefinr/(0,)o
2.06
1.37
1.38
1.36
1.36
1.41
1.15
1.25
1.21
1.25
1.13
1.12
1.28
1.07
1.12
1.34
Cis-2-Butene
(0,)xlQ5
1.20
1.30
1.29
1.24
1.19
0.089
0.040
0.054
0.10
Methyl Propene
(OOnXlO5
1.19
1.21
1.13
1.37
1.36
1.99
2.11
1.56
1.56
1.50
2.11
2.08
2.00
1.00
0.737
1.01
0.930
0.564
0.273
2.15
1.98
2.04
1.49
3.47
4.88
2.20
5.10
4.88
0.222
+ Ozone
(CuHB)n/(0,)n
3.2
2.79
1.71
4.27
4.28
0.77
1.0
0.67
0.37
+ Ozone
(01efinV(0,)n
3.54
2.34
5.04
0.978
1.42
1.12
1.47
1.03
0.864
1 .46
1.18
0.654
1.38
3.84 1.20 3.2 0.91
3.63 1.30 2.79 0.91
2.21 1.29 1.71 1.09
5.30 1.24 4.27 1.12
5.09 1.19 4.28 1.15
0.068 0.089 0.77 1.2
0.039 0.040 1.0 1.0
0.037 0.054 0.67 0.9
0.037 0.10 0.37 0.7
(01efin)nx105 (O^xlO5 (Olef Jn)0/(0,)n n
4.21 1.193.54 1.82
2.83 1.21 2.34 1.68
5.70 1.13 5.04 1.97
1.34 1.37 0.978 1.53
1.93 1.36 1.42 1.58
2.23 1.99 1.12 1.55
3.10 2.11 1.47 1.61
1.60 1.56 1.03 1.37
1.35 1.56 0.864 1.44
2.19 1.50 1.46 1.52
2.50 2.11 1.18 1.46
1.36 2.08 0.654 1.53
2.75 2.00 1.38 1.62
The last four determinations for cis-2-butene in Table 3 were made
with the 5.0 cm diameter by 20.0 cm long cell with an N2 flow of about
35 2,/nrin, and an ozonized oxygen flow of about 0.2 £/min.
13
-------
Figures 3 through 7 are graphs of the value of n plotted as a func-
tion of the ratio of (olefin)0/(03)0 for each of the olefins listed in Table
1. The graphs for ethylene, 1-butene, and methylpropene indicate that the
value of n for the chemical reaction increases as the ratio of (olefin)o/(03)0
increases. Similar trends for cis-2-butene and propene may also exist but
are not as pronounced as shown in Figures 4 and 6, although a slight decrease
in n at smaller values of (olefin)0/(03)0 should be noted. Each of the values
of n are subject to approximately ± 10% relative error.
An increase in the value of n with increasing (olefin)0/(03}0 may be
due to some reactive intermediate (or product) reacting vuth either the olefin
or with ozone. The sequence of reactions shown below may qualitatively
account for the trend in n with respect to (olefin)0/(03)0:
olefin + 03 > olefin • 03 (1)
olefin • 03 >• stable products (2)
olefin • 03 v X (3)
X + olefin > Y (4)
X + 03 > I (5)
The species olefin • 03 is assumed to be an ozone olefin adduct, perhaps a
1,2,3-trioxolane, which contains excess energy. The lifetime of such an
intermediate formed in the reaction of cis-2-butene and ozone may have up to
45 kcal/mole excess energy and a lifetime of about 10~n sec [1]. It has
been postulated that the olefin • 03 adduct can decompose to give HCO, C3H7,
C2H5 and CH3CO free radicals in the case of the ozone + cis-2-butene reaction,
CH3CO with the ozone + ethylene reaction, and perhaps C3H7 in ozone + methyl-
propene. These free radicals have been detected by means of a photoioniza-
tion mass spectrometer [1]. Formation of free radicals is represented
14
-------
collectively by reaction (3). Such free radicals can presumably react directly
with the olefin or ozone, giving rise to the observed dependence of stoichio-
metry on the initial ratio of (olefin)0/(03)c, Molecular oxygen was also
present in these stoichiometric determinations. (The partial pressure of 02
in the experiments done with the 1.0 cm by 20 cm cell was about 50 torr.)
Free radicals are known to react with molecular oxygen to produce yet another
generation of radicals capable of destroying either olefin or ozone. In
summary, the fact that the stoichiometry for the reactions of the olefins
described from 1:1 and the observed dependence of n on the ratio of (olefin)0/
both suggest that the reaction is most certainly not a simple bimolecular
reaction between ozone and olefin. A rate constant determined from the mea-
sured decay rate of ozone or olefin should be considered an "apparent rate
constant" and not a "bimolecular rate constant" for the ozone-olefin reaction.
15
-------
0
0
0
01
c
01
1-
0
0
Figure 3. n vs. (ethylene)0/(03)0
16
-------
©
O CO
OJ r—
CNJ O CO ȣ>
CM
CD
Figure 4. n vs. (propene)0/(03)0
17
-------
Figure 5. n vs. (1-butene)o/(03)0
0
©
©
©
©
H 1
CM O CO
*» CM
18
-------
o
X
S
©
©
. i <» «>
©
-------
0
0
0
©
o
m
O
^
?
s.
CM O
CSJ CJ
O 00 *O •*$• CM
r~ O O O O
Figure 7. n vs. (methyl propene)0/(03)0
20
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2. Rates of ozone-olefin reactions
Previous measurements of rates of ozone-olefin reactions have shown
that the chemical reaction appears to be first order in ozone, first order
in olefin and second order overall [2, 3, 4, 7]. The ozone concentration was
determined photometrically as described in the "Experimental Methods" section
and the olefin,concentration, symbolized by (olefin), at any elapsed reaction
time "t" (in seconds) was calculated from Equation (II):
(olefin) = (olefin)0 - nA(03) (II)
where n = moles olefin consumed/moles ozone consumed, A(03) = initial concen-
tration of ozone in moles/liter minus the concentration of ozone at elapsed
reaction time t, and (olefin)0 = initial concentration of olefin in moles/
liter. When necessary, correction for the absorbtion of the 2537 A analyzing
light by products was made by calculating the ozone concentration at elapsed
time t, symbolized by (Os), from the expression:
(03) = (03)(
At -
(Ill)
A0 - A«
where At = absorbance at elapsed reaction time t, A0 = initial absorbance,
A» = absorbance after approximately eight reaction half lives have elapsed,
and (03)0 = initial ozone concentration. Absorbance (or optical density),
as used here, is equal to log I y2- 1, where I and I0 are transmitted light
intensities with and without ozone in the reaction vessel. Values of A°° for
ethyl ene, propene, 1-butene, and methyl propene did not exceed 0.02.
The integrated form of the second order rate equation:
inn T(°3^ . v (olefin)) _ [(olefin)n-n(03)n3kt
log \(olef?n)0 x (03) J -- 2.30
was used to evaluate the value of the apparent second order rate constant,
21
-------
symbolized by k, for the various olefins.
Figures 8 through 11 show the left hand side of Equation (IV), which is
symbolized by f, plotted on the log scale as a function of time in seconds
(t) for ethylene, propylene, 1-butene, and methylpropene. The linearity of
the graphs suggests that these ozone olefin reactions appear to be second
order overall.
22
-------
10.01
9.0
8.0'
7.0
6.0
5.0
4.0-
3.0'
2.0
(C2HJQ = 2.39 x 10-5 M
(03)0 = 1.30 x 1C'5 M
k = 0.88 x 103 Jtraole-1 s"1
time (s)
Figure 8. Second Order Plot. Ethylene + Ozone.
23
-------
10.0-
9.0.
8.0.
7.0-
6.0.
5.0'
4.0
3.0-
2.0-
1.0'
(Propene)0 = 3.33 x 10'5 M
(03)0 = 0.759 x TO'5 M
k « 5.79 x 103 zmole'1 s'1
time (s)
10
Figure 9. Second Order Plot. Propene + Ozone.
24
-------
(l-Butene)0 = 1.74 x 10'5 M
(03)Q « 1.12 x 1(T5 M
k = 5.6 x TO3 nmole-1 s"1
time (s)
Figure 10. Second Order Plot. 1-Butene + Ozone.
25
-------
k = 7.4 x 103 tmole-1 s'1
1.0
time (s)
Figure 11. Second Order Plot. Methylpropene + Ozone.
26
-------
Table 4 is a summary of the apparent second order rate constants as
determined by the methods stated above. The units of k are liters mole^sec"1.
(Olefin)o and (63)0 are initial concentrations of olefin and ozone respec-
tively in moles/liter.
Experiment
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
TABLE 4
APPARENT SECOND ORDER RATE CONSTANTS
FOR SOME OZONE-OLEFIN REACTIONS
Ethylene + Ozone
(CgHjpxlO5
(03)nXl05
5.35
3.55
1.25
2.39
0.775
1.87
1.82
1.73
1.63
1.48
1.46
1.02
0.977
0.699
0.677
0.670
0.654
0.60
0.484
0.478
0.47
0.38
0.112
0.112
Propene +
(C,Hfi)ftxl05
5.32
3.33
2.05
1.83
1.00
1.05
1.34
1.17
1.20
1.25
1.30
1.32
0.310
0.320
0.345
0.324
0.324
0.310
0.612
0.579
0.445
0.443
0.460
0.432
0.0749
0.349
0.325
0.0667
0.0710
0.0787
0.0814
Ozone
(0,)0xl05
1.00
0.759
1.04
0.761
0.750
0.489
0.454
Apparent 2nd Order Rate
Constant x IP"3
0.78
0.76
0.90
0.88
1.0
0.916
0.905
0.923
0.963
0.927
0.919
0.813
1.13
0.969
0.849
1.09
1.20
0.92
1.12
1.06
0.98
0.88
1.5
1.6
Apparent 2nd Order Rate
Constant x 10-3
4.
5.
5,
5.
89
79
66
96
7.3
5.63
5.79
27
-------
TABLE 4 - Cont.
1-butene + Ozone
Experiment
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
*48
(1-CuHft)0xl05
4.39
2.68
1.82
1.74
1.57
1.57
1.55
1.55
0.462
0.462
0.294
0.196
0.114
0.113
0.110
0.105
0.10
(0,)nxl05
1.05
0.643
0.730
1.12
0.246
0.0623
0.138
0.0667
0.285
0.302
0.0765
0.0704
0.0820
0.0798
0.0781
0.0798
0.10
*Plotted as 1/(03) vs. time.
Methylpropene + Ozone
49
50
51
52
53
4.95
48
56
25
Apparent 2nd Order Rate
A Constant x lO"3
1.05
0.643
0.730
1.12
0.246
0.0623
0.138
0.0667
0.285
0.302
0.0765
0.0704
0.0820
0.0798
0.0781
0.0798
0.10
5.6
5.6
5.5
5.6
5.75
6.13
6.2
5.96
5.78
5.60
6.19
6.15
6.2
7.5
7.4
8.8
7.6
Apparent 2nd Order Rate
Constant x IP"3
1.04
1.09
0.745
0.719
1.21
0.795
7.7
8.33
10.6
6.1
7.5
For experiments 1 through 5 in Table 4 the 1.0 cm diameter by 20.0 cm
long reaction cell was used. The N2 flow was about 8.0 s,/min, the ozone-
oxygen mixture flow about 0.6 2,/min and the flow of the C2Hn-N2 mixture about
0.8 £/min, although the flow rate of this mixture was varied to change (C2Hit)0.
The total gas pressure was 795 +_ 10 torr and the temperature of the reaction
cell was 25 +_ 2°C (room temperature).
Experiments 6 through 24 in Table 4 were carried out in the 5.0 cm
diameter by 20.0 cm long reaction vessel. The N2 flow was about 35. £/min
and the C2Hi+-N2 flow rate was varied between about 0.1 and 1.5 £/min. The
28
-------
cell temperature was about 23 +_ 2°C and the total gas pressure in the cell was
about 790 +_ 5 torr. For runs 18, 21, 22, the 02 flow rate was 0.5 £/min and
for the other runs, 6 through 24, the 02 flow rate was about 0.2 to 0.3 £/min.
Experiments 25 through 29 were carried out in the 1.0 cm diameter by
20.0 cm long cell with conditions essentially the same as stated for runs 1
through 5. Experiments 30 and 31 were done in the 5.0 cm diameter by 20.0 cm
long cell with conditions similar to those stated for experiments 6 through 24.
Experiments 32 through 35 were done in the 1.0 cm diameter by 20.0 cm
long cell with conditions similar to those used for runs 1 through 5.
Experiments 36 through 48 were done in the 5.0 cm diameter by 20.0 cm
long cell with conditions essentially the same as for runs 6 through 24. How-
ever, experiments 42 and 43 had an ozonized oxygen flow rate of about 0.4 £/min
whereas the other experiments had an ozonized oxygen flow rate of about
0.2 2,/min.
Since the stoichiometry in the reactions of ethylene, and 1-butene
have not extensively been measured under the conditions stated for experiments
6 through 24 and 36 through 48 a stoichiometry of 1:1 has been used in the
rate plots. It has been reported that the stoichiometric ratio n approaches
1 in pure NZ for ozone-olefin reactions and seems to increase when 02 is
present [3, 8]. Since there is only about 1% 02 in the gas mixtures in runs
6-24 and 36-48 the assumption of 1:1 stoichiometry is somewhat uncertain and
should be measured more thoroughly over a range of (olefin)0/(03)0. However,
experiments done with a slight excess of 03 with 1-butene and ethylene showed
a stoichiometry of 1:1 with 1% 02 in the gas mixture.
The data in Table 4 suggests that there may be a small increase in the
value of k as the initial concentration of the olefin is decreased. In the
case of ethylene k is about 0.8 x 103 amole^sec'1 at (€2^)0 = 5 x 10~5 mole/A
29
-------
and about 1.5 x 103 «,mo1e~1sec~1 at (C2Hlt)0 = 0.1 x 10~5 mole/£. For 1-butene
k is about 5.6 x 103 jwole-isec-1 at (C^H8)0 = 4 x 10~5 mole/a and 8 x 103
Jimole'^ec'1 at (C^HeJo = 0.1 x 10"5 mole/£. A similar trend is noted for
the apparent second order rate constant of propene, although the trend is
quite small and is not much larger than the experimental uncertainty of about
10%. The values for k in the propene reaction range from about 5 x 103 Jimole"1
sec"1 to about 7 x 103 Amole^sec'1.
No trend in the value of k for methylpropene is detectable. The values
of k range from 6 x 103 wnole^sec"1 to 10 x 103 junole^sec"1. Measurements
of k for methylpropene seem to show less reproducibility than for the other
olefins shown in Table 4.
Results for trans-2-butene and cis-2-butene are shown in Table 5.
The stoichiometry of the trans-2-butene-ozone reaction was only measured
under conditions of a slight excess of 03 with initial concentrations of 03
and trans-2-butene of about 10"6 moles/a, with the 5.0 cm diameter by 20.0
cm long cell and about 1% 02 present at a temperature of 25°C. Under these
conditions a value of n = 1.35 +_ 0.1 was determined for the trans-2-butene-
ozone reaction.
30
-------
TABLE 5
APPARENT SECOND ORDER RATE CONSTANTS FOR THE REACTION OF
TRANS-2-BUTENE AND CIS-2-BUTENE WITH OZONE
Trans-2-butene + Ozone
Apparent 2nd Order Rate Constant
(Trans-2-butene)Qx105 (Q^)nx105 _ x
0.097 0.116 150.
0.11 0.106 120.
0.12 0.113 80.
0.12 0.0814 100.
0.12 0.0781 90.
0.12 0.0814 86.
0.13 0.0858 121.
0.16 0.058 85.
Cis-2-butene + Ozone
Apparent 2nd Order Rate Constant
(Cis-2-butenenxlQ5 (0^)nxlQ5 _ x IP3 _
0.23 0.124 73.
0.12 0.11 77.
0.71 0.089 75.
0.043 0.038 130.
0.041 0.034 140.
0.039 0.040 130.
0.037 0.054 120.
0.037 0.10 170.
Figures 12 and 13 show second order rate plots for trans and cis-2-
butene respectively. The adherence to equation IV is fairly good for each
of the olefins at olefin concentrations of 5 x 10~6 mole/5, or less. There
may again be a slight tendency for the measured rate constant to increase as
the olefin concentration is decreased, although such a conclusion is quite
tenuous since the experimental uncertainty is probably on the order of
+ 15% in both cases.
31
-------
lo-
g-
s'-
7—
6—
5--
4-
3-
2—
1 —
(Trans-2-Butene)Q = 0.13 x 10"5 M
(Ozone)0 = 0.0858 x 10"5 M
time (s) 2 4 6 8 10 12 14 16 18 20
Figure 12. Second Order Plot. Trans-2-butene + Ozone.
32
-------
10.0
9.0
8.0
7.0
6.0
5.0.
4.0
3.0
2.0
(C1s-2-Butene)Q = 0.23 x 10"5 M
(03)0 * 0.124 x 10-5 M
k « 73. x 103 wnole-1 sec'1
14
Figure 13. Second Order Plot. Cis-2-butene + Ozone.
33
-------
When the initial concentration of either trans or cis-2-butene is
increased beyond about 5 x 1CT6, large curvature is observed in the graph
of f vs. time as shown in Figure 14 for trans-2-butene.
10.&
9.0'
8.0-
7.0-
6.0-
5.0
4.0
3.0'
2.0-
1.0
©
©
(Trans-2-Butene)0 = 1.92 x 10'5 H
(03)Q = 0.761 x ICT5 M
©
©
678
time (s)
10 11
12 13
14
Figure 14. Second Order Plot. Trans-2-butene + Ozone. High Concentration.
34
-------
Such curvature in the second order rate plots could conceivably be caused by:
1. An inhibition of 03 decomposition by some complex mechanism
2. Aerosol formation
3. A relatively long-lived intermediate which absorbs the 2537 A radia-
tion nearly as strongly as 03. The first possibility was tested by
an experiment designed as shown in Figure 15.
Mixed Reactants
Teflon tubing
(Trans-2-butene)0 = 30. x 1CT5 M
(03)0 = 8 x lO'6 M
Figure 15. Test for Inhibition of 03 Decomposition.
35
-------
The ozone generator was turned on; a steady state condition was reached in
the IR cell and the IR spectrum was scanned from 2.5y to 14y (ly = 1 x 10~6m).
The 03 absorption at 9.6y was no longer detectable, even though the absor-
bance of the 2537 A line was 0.35 in the reaction vessel. The lowest detect-
able limit of 03 was about 10% of the initial 03. Therefore the absorbance
of the 2537 A line in the reaction vessel under these conditions was not due
to the presence of 03. It was therefore concluded that the curvature in the
second order rate plot was not due to an inhibition of 03 decomposition at
high trans-2-butene concentrations.
Under these same conditions, the IR spectrum was examined carefully
for absorptions not due to those measured for 03 or trans-2-butene. Infrared
absorptions at 3y, 5.7u, and 9.1p were observed to be the strongest signals
not due to 03 or trans-2-butene. When the flow of reactants through the IR
cell was stopped, no change in the absorption at any of the three wavelengths
above was observed. Therefore, these absorptions in the IR were not due to
an unstable intermediate. The observed IR spectrum could be due to a mixture
of acetaldehyde, formic acid, water and methanol which are known products
from this reaction [8].
To test for light scattering due to aerosol formation, the beam from
a He-Ne laser was directed through the reaction vessel during a chemical
reaction with (trans-2-butene)0 equal to 30 x 10~5 mole/£ and (ozone)o =
8 x 10~6 mole/£. A strong Tyndall effect was observed, even though no visible
turbidity could be observed in the reaction cell when it was exposed to
ordinary room light. The intensity of the Tyndall beam was observed to
decrease at about the same rate as the absorbance at 2537 A. Presumably this
effect is due to the slow settling of the aerosol particles. It was there-
fore concluded that the curvature in the rate plots, as shown in Figure 14,
36
-------
for the case of both trans and cis-2-butene at higher concentrations (c.a. >
5 x 10~6 mole/£) is due to the formation of an aerosol which scatters the
2537 A analysing light. Therefore, reliable rate measurements using this
method of analysis are not possible for trans and cis-2-butene above concen-
trations of about 10~5 M since a large fraction of the 2537 A light is scatter-
ed by aerosols at these higher concentrations.
After the reaction of trans-2-butene with ozone was run for several
minutes at (trans-2-butene)0 > 1 x 10"5 mole/A and (03)0 - 10"5 mole/2,,
small amounts of liquid were observed to remain in the reaction vessel. The
infrared spectrum for this liquid in CCl^ solvent is shown in Figure 16.
37
-------
o .
CO
o
U3
o ,
o
g ~
••s
§
Figure 16a. Infrared Spectrum of the Aerosol From the Trans-2-butene - Ozone
Reaction.
38
-------
o
cr
I
re
4=0
g
Figure 16b. Infrared Spectrum of the Aerosol From the Trans-2-butene
Reaction.
- Ozone
39
-------
The absorptions have been tentatively assigned to the functional groups as
listed in Figure 16. This aerosol has not been any further characterized,
although such work may be of general interest to further elucidate the reac-
tion mechanism of ozone and trans-2-butene. According to reference 8 products
with molecular masses up to 200 Dal tons have been found in the aerosol pro-
duced in the reaction of ozone and 1-butene. Presumably, the aerosol formed
by the reaction of ozone with trans-2-butene contains such high molecular
weight components as well.
3. Measurement of light scattering by aerosols in the reaction of trans-2-
butene with ozone
Table 6 summarizes the results for a few experiments in which the
scattered light was measured as a function of reaction time. The quantity
Tj is the induction period which is observed after the flow is stopped and
when the first signal from the scattered light is measured. Figure 17 shows
the scattered light intensity, Is (in arbitrary units), as a function of
reaction time.
40
-------
TABLE 6
RESULTS OF LIGHT SCATTERING EXPERIMENTS
FOR THE OZONE + TRANS-2-BUTENE REACTION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
7.84x10-7M
6.01
4.88
5.60
8.04
10.9
14.1
5.18
8.06
8.95
(03)0 =
T =
Total
Pressure =
Total Flow
of Gases
— x
7.5
11.5 ± 1
8. ± 1
8.5 ± 1
4.5 ± 1
2.
1.
10.
4.5
3.
3.6 x 10"6M in
298 ± 1°K in al
760 ± 10 torr i
" 25 Ji/min
19.5
9.5 ± 1
7.6
13.5 ± 1
20. ± 1
(off scale)
(off scale)
8.
38.
71.
all runs
1 runs
n all runs
41
-------
Fiqure 17. Intensity of Scattered Light vs
+ Ozone Reaction.
"ime in the Trans-2-butene
42
-------
12345
Figure 18. Maximum Intensity of Scattered Light vs. Concentration of
Trans-2-butene.
43
-------
The maximum intensity of the scattered light (Imax) 1's a strong func-
tion of initial trans-2-butene concentration as shown in Figure 18. The
exponential equation (V)
Imax= (0.747)exp(.4611) (V)
where (Ci+He^ = trans-2-butene initial concentration describes reasonably well
the dependence of Imax on (C^H^o in the range between (C^H8)0 = 5 x 10"7 M
and (C^H8)0 = 14 x 10"7 M. The solid line is equation (V) plotted along with
aqtual data points.
The induction time is also a strong function of the initial concen-
tration of trans-2-butene. Perhaps the induction period exists because suffi-
cient concentrations of products must exist before particles large enough to
scatter light strongly enough to be detected are formed.
Exploratory experiments done with ethylene, propene, 1-butene, methyl-
propene, and cis-2-butene indicate that aerosols are formed in their reactions
with ozone. In the case of ethylene, detectable light scattering was observed
with (C2Hif)0 = 0.44 x 10~5 mole/£ and (03)0 = 0.75 x 10"5 mole/Ji. Some addi-
tfpnal light scattering data are shown for the ethylene-ozone reaction in
Ta^le 7. Gas flow rates, total pressure and temperature were the same as
described in Table 6.
TABLE 7
LIGHT SCATTERING IN THE ETHYLENE + OZONE REACTION
(C2Hpnx105 (03)nx105
1.09
0.926
0.439
1.77
1.40
0.840
0.684
0.629
0.752
0.647
0.703
0.712
6.
15.
20.
5.
10.
7.
74
31
16
63
65
38
44
-------
The rate of settling of aerosol particles formed in the ethylene-
ozone reaction was approximated from the rate of decay of intensity of the
scattered light. The time required for the scattered light intensity to
decrease to one half of the value of the maximum scattered light intensity
was taken as the time for the average size aerosol particle to travel the
distance equal to the radius of the reaction vessel. Using Stoke 's Law
(equation VI)
where V is the settling rate, r is the diameter of the particle, p is the
difference in density of the particle and N2 at 1 atm and 25°C (p was appro-
ximated as 1 g/cm3) and n is the viscosity of N2 under experimental conditions,
gives an average particle radius of l.Oy. This radius is on the same order
of magnitude as the radius of particles found in polluted air in the Los
Angeles region (9).
45
-------
SECTION IV
REFERENCES
1. Atkinson, R., B. J. Finlayson, and J. N. Pitts, Jr. Private communication.
2. Bufalini, J. J. and A. P. Altshuller, Can. Jour, of Chem., 43_, 2243 (1965).
3. Cox, R. A. and S. A. Penkett, J. Chem. Soc.. Faraday Trans. I, 68_, 1735
(1972).
4. Hanst, P. L., E. R. Stephens, W. E. Scott and R. C. Doerr, Atmospheric
Ozone Olefin Reactions. The Franklin Institute, Philadelphia, Pa. (1958),
5. Johnston, H. S. and H. J. Crosby. J. Chem. Phys.. 2^, 2243 (1954).
6. Schulten, H. R. and U. Schurath. Private communication.
7. Stedman, D. H., C. H. Wu, and H. Niki, J. Phys. Chem., T]_, 2511 (1973).
8. Wei, Y. K. and R. J. Cvetanovic, Can. J. Chem., 4J_, 913 (1963).
9. Williamson, S..J. Fundamentals of Air Pollution, p. 356. Addison-Wesley
Pub. Co. (1973).
46
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TECHNICAL REPORT DATA
(Please read Inductions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/3-76-024
4. TITLE AND SUBTITLE
AN INVESTIGATION OF GAS PHASE OZONOLYSIS
7. AUTHOR(S)
David G. Williamson
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Chemistry Department
California Polytechnic State University
San Luis Obispo, California 93407
3. RECIPIENT'S ACCESSION>NO.
5. REPORT DATE
REACTIONS March 1976
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
lAAnOR
11. CONTRACT/GRANT NO.
Grant No. R-800984
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
Environmental Sciences Research Laboratory Final
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A simple gas phase stopped-flow apparatus has been used to determine
the rates and stoichiometry for the reactions of ozone with ethyl ene,
propene, 1-butene, methyl propene, cis-2-butene, and trans-2-butene.
Measurements of the intensity of light scattered by aerosols
generated by the reaction of ozone with trans-2-butene and with
ethylene were made as a function of reaction time and initial reactant
concentration.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Air pollution
Tests
* Reaction kinetics
* Stoichiometry
* Ozonization
* Alkene hydrocarbons
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
13B
14B
07D
07C
19. SECURITY CLASS (This Report) 21. NO. OF PAGES
UNCLASSIFIED 53
20. SECURITY CLASS (This page) 22. PRICE
UNCLASSIFTFD
EPA Form 2220-1 (9-73)
47
-------
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To be published in, Supersedes, Supplements, etc.
16. ABSTRACT
Include a brief (200 words or less) factual summary of the most significant information contained in the report. If the report contains a
significant bibliography or literature survey, mention it here.
17. KEY WORDS AND DOCUMENT ANALYSIS
(a) DESCRIPTORS - Select from the Thesaurus of Engineering and Scientific Terms the proper authorized terms that identify the major
concept of the research and are sufficiently specific and precise to be used as index entries for catalc >ging.
(b) IDENTIFIERS AND OPEN-ENDED TERMS - Use identifiers for project names, code names, equipment designators, etc. Use open-
ended terms written in descriptor form for those subjects for which no descriptor exists.
(c) COSATI FIELD GROUP - Field and group assignments are to be taken from the 1965 COS ATI Subject Category List. Since the ma-
jority of documents are multidisciplinary in nature, the Primary Field/Group assignment(s) will be specific discipline, area of human
endeavor, or type of physical object. The application(s) will be cross-referenced with secondary Field/Group assignments that will follow
the primary posting(s).
18. DISTRIBUTION STATEMENT
Denote releasability to the public or limitation for reasons other than security for example "Release Unlimited." Cite any availability to
the public, with address and price.
19. &20. SECURITY CLASSIFICATION
DO NOT submit classified reports to the National Technical Information service.
21. NUMBER OF PAGES
Insert the total number of pages, including this one and unnumbered pages, but exclude distribution list, if any.
22. PRICE
Insert the price set by the National Technical Information Service or the Government Printing Office, if known.
:PA Form 222O-1 (9-73) (Reverse)
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