Environ. Sci. Technol. lOBS, 27, 2548-2552
The Reaction of Ozone with MPAN, CH2=C(CHs)C(O)OON02 Daniel Grosjean,' Eric Grosjean, and Edwln L. Wililams I I DGA, Inc., 4526 Telephone Road, Suite 205, Ventura, California 93003
The reaction of ozone with the unsaturated peroxyacyl nitrate MPAN, CH2=C(CH&(O)OONO2, has been studied at ppb levels of MPAN and ozone in the dark and with sufficient cyclohexane added to scavenge the hydroxyl radical. The ozone-MPAN reaction rate constant at ambient temperature (291-297 K)and atmospheric pressure is (8.2 f 2.0) X lo-'*cm3molecule-l s-1 and is consistent with those for other 1,l-disubstituted olefins including unsaturated esters that are close structural homologues of MPAN. The ozone-MPAN reaction mechanism is outlined. Formaldehyde (yield 0.6 f 0.1) is the major carbonyl reaction product. Reaction with ozone may be an important removal process for MPAN in the atmosphere, with, for example, a MPAN half-life of about 18 h when O3 = 50 ppb. Introduction Biogenic hydrocarbons are currently receiving renewed attention for their role in ozone formation in urban and nonurban air (1, 2). The atmospheric chemistry of isoprene, one of the most abundant biogenic hydrocarbons (3),has been the object of many laboratory studies (4-12). In the presence of oxides of nitrogen, the oxidation of isoprene leads to PAN (CH3C(O)OON02) and to the unsaturated peroxyacyl nitrate CHp=C(CH3)C(O)OON02; Chemical Abstracts Service index name 2-methyl-2propenoyl nitro peroxide; common nomenclature name for PAN homologues, peroxymethacryloyl nitrate, hereafter MPAN (7,9,12).MPAN has been characterized in the laboratory (9,12,13), has been measured in ambient air at southern California mountain forest locations that are impacted by urban photochemical pollution (14),and has been measured in urban air in Atlanta, GA (15)where biogenic hydrocarbon emissions may play an important role in urban air quality (2).Since the several peroxyacyl nitrates studied to date have been shown to be phytotoxic and mutagenic (16-18),additional information regarding the atmospheric persistence of MPAN is of obvious importance with regard to the atmospheric chemistry of isoprene and to the corresponding adverse effects on ecosystems. The atmospheric persistence of MPAN is limited by a number of physical and chemical processes. These processes may include deposition, thermal decomposition, reaction with the hydroxylradicaland reaction with ozone. Dry deposition of MPAN has not been studied. The thermal decomposition of MPAN is comparable to that of PAN (19,20). MPAN may react with the hydroxyl radical, and a kinetic and product study of the MPANOH reaction has recently been reported (21). Unlike PAN, whose reaction with ozone is negligibly slow (221, MPAN and other unsaturated peroxyacyl nitrates may react with ozone fast enough for this reaction to be a significant atmospheric loss process. Therefore, the objective of this study was to investigate the MPAN-ozone reaction. The
* Corresponding author. 2548
Envlron. Scl. Technol., Vol. 27, No. 12, 1993
MPAN-ozone reaction rate constant has been measured in experiments involving parts per billion (ppb) levels of MPAN and ozone in the dark at ambient temperature and atmospheric pressure. The corresponding carbonyl reaction products have been characterized. Several experiments were carried out with sufficient hydrocarbon added to scavenge OH,which is a product of the ozoneolefin reaction (23)and whose subsequent reaction with MPAN, if formed in the MPAN-ozone reaction, could complicate the analysis of kinetic and product data. Experimental Methods Experimental methods for the synthesis of MPAN in the liquid phase, for measurements of ppb levels of MPAN in the gas phase by electron capture gas chromatography (EC-GC), for the corresponding calibrations, for experimental studies of the ozone-olefin reaction and for the analysis of the carbonyl reaction products have been described in detail previously (12). Only a brief summary of these methods is given here along with the corresponding references which can be consulted for more details. We synthesized MPAN in the liquid phase using a method described earlier for the preparation of PAN (24) and subsequently applied to other peroxyacyl nitrates including MPAN (12-14,20,25,26). MPAN was prepared by the reaction of methacrylic anhydride (Aldrich, purity 197% with HzOz followed by acid-catalyzed nitration of the resulting peroxy carboxylic acid. Batches of MPAN thus prepared were stored at -5 OC as solutions in n-dodecane (Aldrich, purity 199%). They also contain PAN and, on occasions, an alkyl nitrate tentatively identified as 2-propenyl nitrate, CHz=C(CH3)0N02 (12). MPAN was also prepared in the gas phase by sunlight irradiation, in a 3.5-m3Teflon film chamber, of 0.25 ppm NO and 1ppm of isoprene or methacrolein in purified air (12). The Teflon chamber, the air purification system, and the chemical reactions involved have been described previously (12). Tests employed to characterize MPAN included (a) preparation using two independent methods, Le., synthesis in the liquid phase and in-situ formation in the gas phase as described above (12); (b) thermal decomposition in the gas phase through tubes heated to 150-180 "C and inserted in the sampling line upstream of the EC-GC (12,14,15, 20, 25, 26);(c) decomposition in the gas phase in the and (d) decomposition in presence of excess NO (13,20), the liquid phase, i.e., MPAN C02 + 2-propenyl nitrate, upon standing at room temperature for several hours or after storage at -5 "C for several weeks (12). PAN was included as a reference compound in these tests for comparison (12). MPAN was measured by EC-GC as described before (12,14, 15,25-27) using 30 X 0.3 cm and 70 X 0.3 cm Teflon-lined stainless steel columns packed with 10% Carbowax 400 on Chromosorb P 60/80 mesh. Air was continuously pumped through a short section of 6-mm diameter Teflon tubing connected to a 6.7-mL stainless steel sampling loop housed in the GC oven (T= 36 OC) and
-
0013-936X/93/0927-2548$04.00/0
0 1993 American Chemical Society
Table I. Summary of Experimental Conditions and Kinetic Results 297 & 2 T,K initial concentrations, ppb 4a MPAN 118 ozone 13 PAN 0 n-dodecane 0.1 2-propenyl nitratee 7 experiment duration, h 29 initial ozone/MPAN concentration ratio least-squares linear regression parameters for pseudo-first-order data 2.50 f 0.16 slope f 1SD, 106 s-l -0.037 f 0.023 intercept f 1SD 0.963 correlation coefficient 22 no. of measurements 6.44 second-order reaction rate constant, 10-lscm3molecule-' s-l
291 f 1
296 f 1
296 f 1
20b
lob
9
77 5
50 2
+c
+c,d
+c,d
0
6 4.3
1.9 3 3.9
0.8 3 5.0
1.90 f 0.13 0.013 f 0.014 0.972 15 6.66
2.61 f 0.30 0.016 i 0.013 0.968 9 10.4
18* 78
2.26 h 0.33 0.011 f 0.014
0.949 7
9.2
a MPAN prepared in-situ by sunlight irradiation of isoprene and NO in purified air (12). MPAN synthesized in the liquid phase and introduced in the chamber as a dilute solution in n-dodecane. c Injected as solvent for MPAN, concentration not measured. Also 200 ppm cyclohexane added to scavenge OH. e Calibration factor estimated from measured retention time and from calibration factor vs retention time data for other alkyl nitrates (12).
was injected every 20-30 min using a timer-activated 10port sampling valve. To calibrate the EC-GC instruments, ppb levels of MPAN in the gas phase were obtained by dilution, with purified air, of the output of a diffusion vial containing a solution of MPAN in n-dodecane and maintained at 2 "C. Calibration involved side-by-sidereadings with one or more gas chromatographs and with a chemiluminescent NO, analyzer, which uses a surface converter to convert oxides of nitrogen to NO and responds quantitatively to peroxyacyl nitrates (28). The chemiluminescent NO, analyzer (Monitor Labs 8840) was calibrated using the diluted outputs of a certified cylinder of NO in N2 and of a certified NO2 permeation tube maintained at 30.0 f0.1 "C. Details of the calibration procedure can be found elsewhere (12, 14,20,25). The response of the electron capture detector to MPAN was verified to be linear in the range of MPAN concentrations employed in this study, 2-20 ppb. The reaction of MPAN with ozone was studied in the dark at ambient temperature (291-297 K)and atmospheric pressure using ppb levels of ozone and MPAN in purified air (RH= 55 f 10%)in (3.5-3.7)-m3 all-Teflon chambers covered with opaque plastic film (12,29,30).The purified matrix air contained no detectable amounts of MPAN and PAN and less than 0.1-0.5 ppb of formaldehyde and other carbonyls. Ozone was measured by ultraviolet photometry using a calibrated Dasibi Model 1108 continuous ozone analyzer. Three of the four experiments involved mixtures of ozone, MPAN synthesized in the liquid phase, and n-dodecane. Cyclohexane (200 ppm, Aldrich, purity >99%) was added after ozone and before MPAN in two of these experiments. The fourth experiment involved mixtures of ozone and MPAN, with MPAN prepared insitu from sunlight irradiation of isoprene and nitric oxide. Cyclohexane and n-dodecane were not included in this experiment, in which unreacted isoprene, nitrogen dioxide, and carbonyls and other products of isoprene oxidation were present along with ozone and MPAN. Initial concentrations and experimental conditions are summarized in Table I. In the experiments involving MPAN prepared in the liquid phase, ozone was produced using the built-in generator of the ozone analyzer and was introduced first into the chamber. MPAN was introduced next by injecting an aliquot of its solution in n-dodecane into a 200 cm3
glass bulb and by flushing, using purified air, the contents of the glass bulb into the chamber through a short section of Teflon line. Losses of ozone and MPAN to the chamber walls were measured in separate experiments carried out in the dark and involving ozone alone and MPAN alone in purified air. The loss rates were, in units of lo4 s-l, 6.5 f 0.6 for MPAN (mean f 1 SD, three experiments), 6.4 f 0.6 for ozone in one Teflon chamber, and 1.5 f 0.6 for ozone and 2.0 f 0.2 for MPAN (two experiments) in another Teflon chamber. Results for ozone are consistent with literature data for ozone wall loss in similar Teflon film chambers (30). Results for MPAN are consistent with those previously obtained for other peroxyacyl nitrates in the same Teflon chambers (12, 14). Control experiments were carried out with mixtures of ozone and n-dodecane, ozone and cyclohexane, and ozone and both hydrocarbons (no MPAN present). The ozone loss rate measured in the presence of cyclohexane r(1.25 f 0.15) X 10-6 s-1 (two experiments)] was the same as that for ozone loss to the chamber walls. The higher ozone loss rate measured in the presence of n-dodecane I(14.7 f 2.1) X lo6s-l (two experiments), indicated that n-dodecane contained trace amounts of ozone-consuming impurities. Carbonyl products of the MPAN-ozone reaction were isolated as their 2,4-dinitrophenyl hydrazones by sampling the reaction mixture through small CIScartridges coated with twice recrystallized 2,4-dinitrophenylhydrazine (DNPH) as described previously (31,321. The cartridge sampling flow rate was 0.9 L/min. The cartridges were eluted with HPLC-grade acetonitrile, and aliquots of the acetonitrile extracts were analyzed by liquid chromatography with ultraviolet detection at 360 nm using a 110 X 4.7mm CIScolumn and 55:45 by volume CH3CN-H20 as eluent (31,32). Quantitative analysis involved the use of external hydrazone standards, from which calibration curves, i.e., absorbance (peak height) vs concentration, were constructed. More details regarding the sampling and analytical protocols have been given elsewhere (31, 32).
Results and Discussion MPAN-Ozone Reaction Rate Constant. The reaction of MPAN with ozone in the dark was studied at room temperature and atmospheric pressure, with initial MPAN Envlron. Sci. Technol., Vol. 27, No. 12, 1993 2649
0.:
-
0.2
Y
T
d
-
3 0
T
2
3
-
I
0.1
0.0 0
2000
4000
6000
8000
I( 0
Time. sec
Flgure 1. Scatter plot of In (MPAN),/(MPAN), vs time.
concentrations of 4-20 ppb. The reaction was studied under pseudo first-order conditions, with initial ozone/ MPAN concentration ratios of 4-27. Plots were constructed of In [MPANl,/[MPANlt vs time, where [MPAN], and [MPANlt are the initial concentration of MPAN and the concentration of MPAN at time t , respectively. As is shown in Figure 1, these plots were linear with near-zero intercepts. Least squares linear regression analysis of the data yielded the slopes listed in Table I. The relative standard deviations on the slopes, a measure of experimental precision, ranged from 6 to 14% and averaged 10%. These slopes, after correction for the measured MPAN loss to the chamber walls, and using the measured initial ozone concentrations, yielded the second-order reaction rate constants listed in Table I. The mean of these individual determinations is (8.2 f 2.0) X 10-l8 cm3 molecule-' s-1. The relative standard deviation on the rate constant, 24%, reflects to a large extent day-to-day variations in overall EC-GC instrument response to ppb levels of MPAN (12, 15). Kinetic Data. We elected to measure the reaction rate constant by following the concentration of MPAN vs time rather than by using ozone vs time data. This is because ozone may react not only with MPAN but also with olefins that may be present in small amounts as impurities in the hydrocarbons we employed to scavenge OH (see below) or to prepare solutions of MPAN, i.e., cyclohexane and n-dodecane, respectively. Indeed, control experiments indicated the presence of ozone-consuming impurities in n-dodecane but not in cyclohexane. Ozone may also react with the unsaturated organic nitrate as well as with other olefinicbyproducts that may form when preparing MPAN and that were not detected by electron capture gas chromatography. These ozone-consuming reactions do not introduce a bias in the kinetic data if the ozone-MPAN reaction rate constant is derived from measurements of the concentration of MPAN as a function of reaction time. 2550
Environ. Sci. Technol., Vol. 27, No. 12, 1993
The hydroxyl radical is a product of the dark reaction between ozone and olefins (23). In the three experiments in which MPAN was obtained from solutions of MPAN in n-dodecane, n-dodecane was probably present at levels high enough to scavenge most of the OH formed, if any. To obtain a large and measurable amount of hydrocarbon as a scavenger for OH, we added cyclohexane rather than adding more n-dodecane in two of the experiments (cyclohexane is more volatile, therefore easier to inject, and does not contain ozone-consuming impurities). The effectiveness of cyclohexane as a scavenger for OH may be estimated from kinetic data. The room temperature rate constants for the OH-cyclohexane and OH-MPAN cm3 molecule-' s-1 (22) and (3.6 reactions are 7.5 X f 0.4) X 10l2cm3 molecule-l s-1 (211, respectively. Thus, with initial cyclohexane/MPAN concentration ratios of (5-20) X lo3, more than 99.9% of the OH that may form as a product of the ozone-MPAN reaction would react with cyclohexane under the conditions of our study. Consequently, the reaction of MPAN with OH is expected to make a negligible contribution to the measured MPAN concentrations from which our kinetic data are derived. Other reactions that may consume MPAN under the conditions of our study include thermal decomposition and, perhaps, reaction with the nitrate radical. As noted in the experimental section, control experiments with MPAN in purified air showed that thermal decomposition was negligible. In the experiments with MPAN and ozone (with n-dodecane and cyclohexane also present), we monitored the concentrations of PAN and methyl nitrate. The observed loss rate for methyl nitrate, which does not undergo thermal decomposition, was consistent with its wall loss rate as measured in separate control experiments (12). The observed loss rate for PAN, whose reaction with ozone is negligibly slow (22),was (4.1 f 1) X 10-6, (4.2 f 2.3) X lo4, and C0.5 X lo4 s-l. These loss rates are consistent with PAN chamber wall loss rates measured previously with PAN alone in pure air (12, 20). These results demonstrate that thermal decomposition was not a significant loss process for PAN and, therefore, for MPAN, under the conditions of this study. Since thermal decomposition played a minor role, the amount of NO2 available to react with ozone and produce the nitrate radical was small, and the NO3-MPAN reaction made a negligible contribution to the overall consumption of MPAN. This is supported (but not demonstrated) by the results from the experiment in which MPAN was prepared from isoprene. In this experiment, the high initial NO2 and ozone concentrations were conducive to more NO3formation than was the case in the other runs; yet the measured ozone-MPAN rate constant measured in this experiment was no higher (infact slightly lower) than those measured in the other runs. Comparison with Structural Homologues. The reactivity of MPAN toward ozone is consistent with that of structurally similar compounds, i.e., 1,l-disubstituted olefins. Ozone reaction rate constants are available for only four 1,l-disubstituted olefins, CH2=CRlR2; the three alkenes isobutene (R1= R2 = CH3), 2-methyl-1-pentene (R1= CH3,R2 = n-propyl), and 2-ethyl-1-butene (R1= R2 = ethyl); and the unsaturated ester methyl methacrylate (R1= CH3, Rz = C(0)OCHs). Also relevant as structural homologues of MPAN are the two unsaturated esters vinyl acetate, CHz=CHC(O)OCH3, and methyl crotonate, CH3CH=CHC(O)OCH3. The corresponding ozone reaction
rate constants, in units of 10-18 cm3m0lecule-~s-l, are 11.5 for isobutene (33),16.9for 2-methyl-1-pentene (34))8.1 f 0.3 for 2-ethyl-1-butene (35))7.5 f 0.9 for methyl methacrylate (35))4.4 f 0.3 for methyl crotonate (31% and 2.9 f 0.3 for vinyl acetate (35) as compared to 8.2 f 2.0 for MPAN. Thus, replacing a hydrogen atom in propene by an alkyl group results in a slight increase in reactivity. Conversely,replacing H by the electron-withdrawing C(0)OCH3group results in a decrease in reactivity. The effect of the C(O)OON02 substituent on the reactivity of the unsaturated carbon-carbon bond toward ozone is likely to be comparable to that of the C(O)OCH3 substituent. Indeed, the rate constant measured for MPAN is comparable to that of its closest structural homologue methyl methacrylate (35). Reaction Products. Formaldehyde was the only carbonyl product that could be positively identified in the MPAN-ozone experiments. Acetone, methacrolein, hydroxyacetaldehyde and several other carbonyls would have been observed if formed even in small yields (about 0.5 ppb or 5 5% yield) but were not detected. The formaldehyde yield averaged 0.6 f 0.1 (three experiments). The observation of formaldehyde as a major reaction product is consistent with the following reaction mechanism, which extends the major features of the ozoneolefin reaction (21, 29, 36-40) to the reaction of the 1,ldisubstituted alkene MPAN with ozone. This reaction is expected to proceed by electrophilic addition of ozone on the unsaturated carbon-carbon bond followed by decomposition of the 1,2,3-trioxolane adduct into two carbonyls and two Criegee biradicals: MPAN
+
O3
-
1,2,3-trioxolane
-
HCHO + 606(CH3)C(0)OONOz
(la) CH$C(O)OONOz + HzdO6
I1
(Ib)
0
+
Acknowledgments This work has been supported by the Southern California Edison co., Rosemead, CA, and by internal R&D funds, DGA, Inc., Ventura, CA. Ms. Denise Velez prepared the draft and final versions of the manuscript.
Literature Cited
(5)
0 + CH3C(0)R (2a)
(6)
CH,=C(R)OOH
(7)
-
(2b) followed by rearrangement of the unsaturated hydroperoxide: CH,=C(R)OOH
-
(RC(O)CH,OH)*
-
-
-
RC(0)CH20H (3a) H,
+ RC(0)CHO (3b)
R e 0 + cH20H (34
OH + RC(O)cH, (3d) Formaldehyde, which forms directly in reaction l a may also form by reaction of oxygen with the hydroxymethyl
J. Air Pollut. Control Assoc. 1972, 22, 537-543. Chameides, W. L.; Lindsay, R. W.; Richardson, J., Kiang, C. S. Science 1988,241, 1473-1475. Lamb, B.; Guenther, A.; Gay, D.; Westberg, H. Atmos. Environ. 1987, 21, 1695-1705. Kamens, R. M.; Gery, M. W.; Jeffries, H. E.; Jackson, M.; Cole, E. I. Int. J. Chem. Kinet. 1982,14, 955-975. Niki, H.; Maker, P. D.; Savage, P. M.; Breitenbach, L. P. Environ. Sci. Technol. 1983, 17, 312A-322A. Gu, C. I.; Rynard, C. M.; Hendry, D. G.; Mill, T. Environ. Sci. Technol. 1985, 19, 151-156. Tuazon, E. C.: Atkinson. R. Int. J. Chem. Kinet. 1990.22. .. --, 1221-1236. Tuazon, E. C.; Atkinson, R. Int. J.Chem. Kinet. 1989,21, 1141-1152. Tuazon, E. C.; Atkinson, R. Int. J. Chem. Kinet. 1990,22, 591-602. Paulson, S. E.; Flagan, R. C.; Seinfeld, J. H. Int. J. Chem. Kinet. 1992,24, 79-101. Paulson, S. E.; Flagan, R. C.; Seinfeld, J. H. Int. J. Chem. Kinet. 1992,24, 103-125. Grosjean, D.; Williams, E. L.; Grosjean, E. Enuiron. Sci. Technol. 1993,27,830-840. Bertman,S. B.;Roberts, J. M. Geophys.Res. Lett. 1991,18, 1461-1464. Grosjean, D.; Williams, E. L., 11; Grosjean, E. Environ. Sci. Technol. 1993,27, 110-121. Williams, E. L., 11; Grosjean, E.; Grosjean, D. J.Air Waste Manage. Assoc. 1993,43, 873-879. Taylor, 0. C. J. Air Pollut. Control Assoc. 1969, 19, 347351. Peak, M. J.; Belser, W. L. Atmos. Environ. 1969, 3, 385397.
(1) Rasmussen, R. A.
The measured yield for formaldehyde formed in pathway l a (0.6 f 0.1) suggests that the more substituted Criegee biradical is preferentially formed. This biradical contains a methyl substituent and, again by analogy with simpler methyl-substituted Criegee biradicals (29, 37, 40)) may decompose as is shown below, leading to PAN-like carbonyl, hydroxycarbonyl, and dicarbonyl products: CH3c(R)06 (R = C(O)OONO,)
-.
radical, i.e., pathway 3c followed by CHzOH + 0 2 HO2 HCHO. Pathways 2b plus 3b constitute a simple, but untested, reaction sequence by which OH could form as a product of the MPAN-ozone reaction. The PAN-like carbonyl, hydroxycarbonyl, and dicarbonyl compounds postulated to form in pathways ( l b plus 2b), 3a, and (3b plus 3d), respectively, were not observed by either electron capture gas chromatography or liquid chromatography. Concluding Comments. Our results indicate that reaction with ozone may be an important removal process for MPAN in the atmosphere. For example, the half-life of MPAN against removal by ozone is about 18h at ambient ozone levels of 50 ppb and about 9 h when 0 3 = 100 ppb. MPAN is more reactive toward ozone than is its direct precursor methacrolein, which is formed in the OHinitiated and ozone-initiated oxidation of isoprene (4-12). MPAN also reacts with OH (21) with a half-life of about 2.2 days when ambient OH averages 1.0 X lo6 molecule cm-3. Since MPAN and PAN have comparable thermal decomposition rates, the reactions of MPAN with ozone and with OH will further reduce the atmospheric persistence of MPAN, relative to that of PAN, and therefore will reduce its importance as a reservoir for long-range transport of reactive nitrogen. The MPAN-ozone and MPAN-OH reactions both produce formaldehyde, which plays a major role in photochemical air pollution including oxidant formation.
(2) (3) (4)
I
'
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(18) Kleindienst, T. E.; Shepson, P. B.; Edney, E. 0.; Claxton, L. D. Mutat. Res. 1985,157,123-128. (19)Roberts, J. M.; Bertman, S. B. Int. J. Chem. Kinet. 1992, 24, 297-307. (20) Grosjean, D.; Grosjean, E.; Williams, E. L., 11. Thermal decomposition of Cs-substituted peroxyacyl nitrates. Res. Chem. Zntermed., in press. (21)Grosjean, D.; Williams, E. L., 11; Grosjean, E. Gas phase reaction of the hydroxyl radical with the unsaturated peroxyacyl nitrate CHpC(CH&(O)OONOz. Int. J. Chem. Kinet., in press. (22)Atkinson, R. Atmos. Enuiron. 1990,24A,1-41. (23)Atkinson, R.; Aschmann, S. M.; Arey, J.; Shorees, B. J. Geophys. Res. 1992,97,6065-6073. (24) Gaffney, J. S.;Fajer, R.; Senum, G. I. Atmos. Enuiron. 1984, 18,215-218. (25)Williams, E. L.,11;Grosjean, D. Environ. Sci. Technol. 1991, 25,653-659. (26) Grosjean, D.;Williams, E. L., 11;Grosjean, E. Enuiron. Sci. Technol. 1993,27,326-331. (27) Williams, E. L., 11; Grosjean, D. Atmos. Environ. 1990,24A, 2369-2377. (28) Grosjean, D.; Harrison, J. Environ. Sci. Technol. 1985,19, 749-752. (29) Grosjean, D. Enuiron. Sci. Technol. 1990,24,1428-1432. (30) Grosjean, D. Enuiron. Sci. Technol. 1985,19,1059-1065.
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(31)Druzik, C. M.; Grosjean, D.; Van Neste, A.; Parmar, S. S. Znt. J. Environ. Anal. Chem. 1990,38,495-512. (32) Grosjean, D. Enuiron. Sci. Technol. 1991,25,710-715. (33) Greene, C. R.;Atkinson, R. Znt. J. Chem. Kinet. 1992,24, 803-811. (34) Cox, R. A.; Penkett, S.A. J. Chem. SOC.Faraday Trans. 1 1972,68,1735-1740. (35) Grosjean, D.;Grosjean, E.; Williams, E. L., 11.Int. J. Chem. Kinet. 1993,25,783-794. (36) Carter, W. P. L. Atmos. Environ. 1990,24A, 481-518. (37) Martinez, R.I.; Herron, J. T. J. Phys. Chem. 1987,91,946953. (38) Martinez, R. I.; Herron, J. T. J. Phys. Chem. 1988,92,46444648. (39) Niki, H.; Maker, P. D.; Savage, C. M.; Breitenbach, L. P.; Hurley, M. D. J. Phys. Chem. 1987,91,941-946. (40) Grosjean, D.; Grosjean, E.; Williams, E. L., 11. Atmospheric chemistry of olefins: a product study of the ozone-alkene reaction with cyclohexane added to scavenge OH. Enuiron. Sci. Technol., submitted. Received for review March 10, 1993.Revised manuscript received July 9,1993.Accepted July 29, 1993.' Abstract published in Advance ACS Abstracts, September 15, 1993. @
