Atmosphere pinene reactions

Vereecken and Peelers (2000) reported that acetone is formed from the reaction of a-pinene and OH radicals in the atmosphere. This reaction resulted in an acetone yield of 8.5% which is consistent with available experimental data. 

As exemplified by the stmctural formulas of a-pinene, P-pinene, A -carene, isoprene, and limonene, shown in Figure 16.1, terpenes contain alkenyl (olefinic) bonds, in some cases two or more per molecule. Because of these and other structural features, terpenes are among the most reactive compounds in the atmosphere. The reaction of terpenes with hydroxyl radical is very rapid, and terpenes also react with other oxidizing agents in the atmosphere, particularly ozone, O3. Turpentine, a mixture of terpenes, has been widely used in paint because it reacts with atmospheric oxygen to form a peroxide, then a hard resin. It is likely that compounds such as a-pinene and isoprene undergo similar reactions in the atmos-... 

Grosjean D, EL Williams, E Grosjean, JM Andino, JH Seinfeld (1993c) Atmospheric oxidation of biogenic hydrocarbons reaction of ozone with 3-pinene, D-limonene, and rra -caryophyllene. Environ Sci Technol 27 2754-2758. 

Organic aerosols formed by gas-phase photochemical reactions of hydrocarbons, ozone, and nitrogen oxides have been identified recently in both urban and rural atmospheres. Aliphatic organic nitrates, such dicarboxylic acids as adipic and glutaric acids, carboxylic acids derived from aromatic hydrocarbons (benzoic and phenylacetic acids) and from terpenes emitted by vegetation, such as pinonic acid from a pinene, have been identified. The most important contribution in this held has been that of Schuetzle et al., who used computer-controlled... 

Grosjean, D., E. L. Williams, II, E. Grosjean, J. M. Andino, and J. H. Seinfeld, Atmospheric Oxidation of Biogenic Hydrocarbons Reaction of Ozone with /J-Pinene, d-Limonene, and trans-Caryophyllene, Em iron. Sci. Techriol., 27, 2754-2758 (1993a). 

Hallquist, M I. Wangberg, and E. Ljungstrom, Atmospheric Fate of Carbonyl Oxidation Products Originating from a-Pinene and A3-Carene Determination of Rate of Reaction with OH and N03 Radicals, UV Absorption Cross Sections, and Vapor Pressures, Environ. Sci. TechnoL, 31, 3166-3172 (1997). 

Hatakeyama, S., K. Izumi, T. Fukuyama, H. Akimoto, and N. Washida, Reactions of OH with a-Pinene and /3-Pinene in Air Estimate of Global CO Production from the Atmospheric Oxidation of Terpenes, J. Geophys. Res., 96, 947-958 (1991). 

In addition to being oxidized by the hydroxyl radical, alkenes may react with the N03 radical as has been described by several investigators (52, 56, 66). Listed in Table I are some of the organic nitrates that have been predicted to be produced via reaction of OH and N03 with isoprene and pro-pene. Analogous compounds would be expected from other simple alkenes and from terpenes such as a- and (3-pinene. Other possible organic nitrates may be produced via the oxidation of aromatic compounds (53, 54) and the oxidation of carbonaceous aerosols (67). Quantitative determination of these species has not been made in the ambient atmosphere. 

Product study and mechanisms of the reactions of alpha-pinene and of pinonaldehyde with OH radicals. Journal of Geophysical Research-Atmospheres, 104 (D19), 23645-56. 

In a 2-L, three-necked flask fitted with a condenser, mechanical stirrer, and a gas inlet tube Is placed 90.0 g (0.66 mol) of (-)-a-pinene (Note 15), The flask 1s cooled to 0°C and under an inert atmosphere a total of 300 mL (0,30 mol) of 1 M borane in tetrahydrofuran (Note 16) Is added dropwise over a 1-hr period. The solution is stirred for 18 hr at 0°C during which time a white precipitate of (+)-di-3-pinanylborane forms. This, solution is then cooled to -78°C. The ca. 0.30 mol solution of methyl 2,4-cyclopentadiene-l-acetate (Part B) 1s transferred at -78°C to a 500-mL pressure-equalizlng dropping funnel through a U-tube in an Inert atmosphere, and is added rapidly, In one portion, to the stirring solution of di-3-pinanylborane at -78°C. After this mixture is stirred for 6 hr at -78°C, the bath temperature is allowed to rise to 0°C and the mixture is stirred for 16 hr at 0°C to complete the hydroboratlon reaction. 

Oxidation of hydrocarbons has long been considered as a fundamental problem to atmospheric chemists, both from experimental and theoretical points of view, because of the inherent complexity. The reaction kinetics and mechanism of atmospheric hydrocarbons have been the focuses of numerous researches in both experimental and theoretical aspects. Although advances have been made in elucidation of the VOC oxidation mechanisms, large uncertainty and tremendous numbers of unexplored reactions still remain. Several review articles on the atmospheric degeneration of VOCs have been published [4,11-14]. In this review, recent advances in the application of theoretical methods to the atmospheric oxidation of biogenic hydrocarbons are discussed. We will introduce the backgrounds on the quantum chemical calculations and kinetic rate theories, recent progress on theoretical studies of isoprene and a-, y3-pinenes, and studies on other monoter-penes and sesquiterpenes. 

In a polluted or urban atmosphere, O, formation by the CH4 oxidation mechanism is overshadowed by the oxidation of other VOCs. Seed OH can be produced from reactions 4 and 5, but the photodisassociation of carbonyls and nitrous acid [7782-77-6]y HN02, (formed from the reaction of OH + NO and other reactions) are also important sources of OH in polluted environments. An imperfect, but useful, measure of the rate of O 3 formation by VOC oxidation is the rate of the initial OH-VOC reaction, shown in Table 4 relative to die OH-CH4 rate for some commonly occurring VOCs. Also given are the median VOC concentrations. Shown for comparison are the relative reaction rates for two VOC species that are emitted by vegetation isoprene and OC-pinene. In general, internally bonded olefins are the most reactive, followed in decreasing order by terminally bonded olefins, multialkyl aromatics, mono alkyl aromatics, C5 and higher paraffins, C2 C4 paraffins, benzene, acetylene, and ethane. 

For the synthesis of (+)-citronellol (6), the mixed pinenes were catalytically hydrogenated to give (-)-cis-pinane (7) which was pyrolysed to (-)-citronellene. Application of the Ziegler reaction with aluminium hydride proceeded selectively at the more reactive disubstituted double bond and following atmospheric oxidation and aqueous work-up, (+)-citronellol was isolated identical with that derived by the reduction of natural citronellal by the Ponndorf-Meerwein-Verley method (ref.9) as shown. 

Chambers were also used in the research on heterogeneous reactions of isoprene and of other atmospheric trace compounds. As already discussed, Czoschke et al. (2003) studied the formation of SOA from products of isoprene oxidation in 500 dm Teflon-bag chambers at UNC. FoUcers et al. (2003a,b,c) studied the partitioning and influence of dicarboxylic acids on aerosol formation in Aerosol Chamber in Julich. Shantz et al. (2003) investigated the growth of aqueous organic particles and cloud condensation nuclei in the CALSPAN chamber, linuma et al. (2004 paper submitted to this book) studied the reaction of a-pinene with ozone on acidic particles in the Leipzig tent-chamber (9 m ). 

Another example of the cyclodextrin cavity s role in complexation photochemistry is given by Weber et al. [96] who reported the photosensitized enantio-differentiating oxygenation of racemic a-pinene (31), using a porphyrin tethered to a p-cyclodextrin derivative (32) (Fig. 6). Upon irradiation with visible light (A, > 350 nm) in the presence of atmospheric oxygen for 8 h, several oxidation products were obtained. The ratios of these products were found to differ depending on the solvent employed, but it was noted that the (S) enantiomers were always formed in excess. For the reaction in the presence of 5 equivalents of 2-methylpyridine, excellent ee s of up to 67% for the (S)-1,2-epoxide (33) and 57%... 

Grosjean, D., E.L. Williams, E. Grosjean, J.M. Andino, and J.H. Seinfeld. 1993c. Atmospheric oxidation of biogenic hydrocarbons reaction of ozone with [i-pinene, D-liminene, and frans-caryophyllene. Environ. Sci. Technol. rZ7 2754—2758. Grosser, R.J., D. Warshawsky, and J.R. Vestal. 1991. Indigenous and enhanced mineralization of pyrene, benzo[a]pyene, and carbazole in soils. Appl. Environ. Microbiol. 57 3462-3469. 

Alternatively, 800 mL (400 mmol) of a 0.5 M solution of 9-BBN in THF and 61.3 g (450 inmol) of ( + )- .-pinene may be refluxed under nitrogen lor 4 h. The solution may be used direclly or the solvent may be removed by water aspirator vacuum followed by pumping at 0.05 Torr for 2 h. The vacuum should be bled with nitrogen to maintain an inert atmosphere in the reaction flask. 

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