Sunlight irradiation

Figure L Selected IR spectra from the UDMH + Os experiments (NHs absorptions subtracted) (a) UDMH prior to Os injection (b) 2 min after Os injection (c) approximately 1 h into sunlight irradiation of reaction mixture.

Shakir, h, et ah, Mo03-MWCNTs nanocomposites photocatalyst with control of lightharvesting under visible and natural sunlight irradiation. Journal of Materials Chemistry,... 

The possibility of widespread haze formation by sunlight irradiation of terpenoid compounds from vegetation was first suggested by Went. Went, Rasmussen and Went, and Rasmussen estimated the annual worldwide contribution of forest hydrocarbon emission and con-... 

Photooxidation of chlorobenzene in air containing nitric oxide in a Pyrex glass vessel and a quartz vessel gave 3-chloronitrobenzene, 2-chloro-6-nitrophenol, 2-chloro-4-nitrophenol, 4-chloro-2-nitro-phenol, 4-nitrophenol, 3-chloro-4-nitrophenol, 3-chloro-6-nitrophenol, and 3-chloro-2-nitrophenol (Kanno and Nojima, 1979). A carbon dioxide yield of 18.5% was achieved when chlorobenzene adsorbed on silica gel was irradiated with light (A. >290 nm) for 17 h. The sunlight irradiation of chlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 28 d yielded 1,060 ppm monochlorobiphenyl (Uyeta et al., 1976). 

Grosjean et al. (1996) investigated the atmospheric chemistry of cyclohexene with ozone and an ozone-nitrogen oxide mixture under ambient conditions. The reaction of cyclohexene and ozone in the dark yielded pentanal and cyclohexanone. The sunlight irradiation of cyclohexene with ozone-nitrogen oxide yielded the following carbonyls formaldehyde, acetaldehyde, acetone, propanal, butanal, pentanal, and a C4 carbonyl. 

Photolytic. When an aqueous solution of p,//-DDE (0.004 pM) in natural water samples from California and Hawaii were irradiated (maximum X = 240 nm) for 120 h, 62% was photooxidized to jD,p -dichlorobenzophenone (Ross and Crosby, 1985). In an air-saturated distilled water medium irradiated with monochromic light (>. = 313 nm), p,//-DDE degraded to jo,//-dichloro-benzophenone, l,l-bis(p-chlorophenyl)-2-chloroethylene (DDMU), and l-(4-chlorophenyl)-l-(2,4-dichlorophenyl)-2-chloroethylene (o-chloro DDMU). Identical photoproducts were also observed using tap water containing Mississippi River sediments (Miller and Zepp, 1979). The photolysis half-life under sunlight irradiation was reported to be 1.5 d (Mansour et al., 1989). 

Photolytic. The sunlight irradiation of 1,3-dichlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 56 d yielded 520 ppm trichlorobiphenyl (Uyeta et al., 1976). 

Photolytic. Sunlight irradiation of a methyl mercaptan-nitrogen oxide mixture in an outdoor chamber yielded formaldehyde, sulfur dioxide, nitric acid, methyl nitrate, methanesulfonic acid, and an inorganic sulfate (Grosjean, 1984a). 

Photolytic. Sunlight irradiation of 2-methylphenol and nitrogen oxides in air yielded the following gas-phase products acetaldehyde, formaldehyde, pyruvic acid, peroxyacetyl nitrate, nitrocresols, and trace levels of nitric acid and methyl nitrate. Particulate phase products were also identified and these include 2-hydroxy-3-nitrotoluene, 2-hydroxy-5-nitrotoluene, 2-hydroxy-3,5-dinitrotoluene, and tentatively identified nitrocresol isomers (Grosjean, 1984). Absorbs UV light at a maximum wavelength of 270 nm (Dohnal and Fenclova, 1995). 

When an aqueous solution containing pentachlorophenol (45 pM) and a suspension of titanium dioxide (2 g/L) was irradiated with UV light, carbon dioxide and HCl formed in quantitative amounts. The half-life for this reaction at 45-50 °C is 8 min (Barbeni et al, 1985). When an aqueous solution containing pentachlorophenol was photooxidized by UV light at 90-95 °C, 25, 50, and 75% degraded to carbon dioxide after 31.7, 66.0, and 180.7 h, respectively (Knoevenagel and Himmelreich, 1976). The photolysis half-lives of pentachlorophenol under sunlight irradiation in distilled water and river water were 27 and 53 h, respectively (Mansour et al., 1989). 

Photolytic. Irradiation of trifluralin in hexane by laboratory light produced a,a,a-trifluoro-2,6-dinitro-A-propyl-jo-toluidine and a,a,a-trifluoro-2,6-dinitro-p-toluidine. The sunlight irradiation of trifluralin in water yielded a,a,a-trifluoro-A, 7 -dipropyl-5-nitrotoluene-3,4-diamine, a,a,a-trifluoro-A/ ,A/ -dipropyltoluene-3,4,5-triamine, 2-ethyl-7-nitro-5-(trifluoromethyl)benzimidazole, 2,3-dihydroxy-2-ethyl-7-nitro-l-propyl-5-(trifluoromethyl)benzimidazoline, and 2-ethyl-7-nitro-5-(trifluoromethyl)benzimidazole. 2-Amino-6-nitro-a,a,a-trifluoro-p-toluidine and 2-ethyl-5-nitro-7-(trifluoromethyl)benzimidazole also were reported as major products under acidic and basic conditions, respectively (Crosby and Leitis, 1973). In a later study, Leitis and Crosby (1974) reported that trifluralin in aqueous solutions was very unstable to sunlight, especially in the presence of methanol. The photodecomposition of trifluralin involved oxidative TV-dealkylation, nitro reduction, and reductive cyclization. The principal photodecomposition products of trifluralin were 2-amino-6-nitro-a,a,a-trifluoro-jo-toluidine, 2-ethyl-7-nitro-5-(trifluoromethyl)benzimida-zole 3-oxide, 2,3-dihydroxy-2-ethyl-7-nitro-l-propyl-5-(trifluoromethyl)benzimidazole, and two azoxybenzenes. Under alkaline conditions, the principal photodecomposition product was 2-ethyl-7-nitro-5-(trifluoromethyl)-benzimidazole (Leitis and Crosby, 1974). 

CASRN 75-18-3 molecular formula C2H0S FW 62.14 Photolytic. Sunlight irradiation of a mixture of methyl sulfide (initial concentrations 0.2-2.5 ppm) and oxides of nitrogen (86-580 ppb) in an outdoor chamber at various time intervals (2-7 h) yielded nitrogen dioxide, ozone, sulfur dioxide, nitric acid, formaldehyde, and methyl nitrate, a sulfate aerosol, and methane sulfonic acid (Grosjean, 1984a). 

Photolytic. Photoproducts reported from the sunlight irradiation of propanil (200 mg/L) in distilled water were 3 -hydroxy-4 -chloropropionanilide, 3 -chloro-4 -hydroxypropionanilide, 3, 4 -di-hydroxypropionanilide, 3 -chloropropionanilide, 4 -chloropropionanilide, propionanilide, 3,4-di-chloroaniline, 3-chloroaniline, propionic acid, propionamide, 3,3, 4,4 -tetrachloroazobenzene, and a dark polymeric humic substance. These products formed by the reductive dechlorination, replacement of chlorine substituents by hydroxyl groups, formation of propionamide, hydrolysis... 

Lepine, F., Milot, S., and Vincent, N. Formation of toxic PCB congeners and PCB-solvent adducts in a sunlight irradiated cyclohexane solution of Aroclor 1254, Bull. Environ. Contam. Toxicol, 48(1) 152-156, 1992. 

Decabromodiphenyl ether (BDE-209) is a major industrial product from the polybrominated diphenyl ethers used as flame retardants derivatives of this product have been detected in the environment. After exposure to the land surface, these contaminants adsorb on soil materials and may reach the atmosphere as particulate matter these particulates are subsequently subject to photolytic reactions. In this context, Ahn et al. (2006) studied photolysis of BDE-209 adsorbed on clay minerals, metal oxides, and sediments, under sunhght and UV dark irradiation. Dark and light control treatments during UV and sunlight irradiation showed no disappearance of BDE-209 during the experiments. Data on half-lives and rate constants of BDE-209 adsorbed on subsurface minerals and sediments, as determined by Ahn et al. (2006) and extracted from the literature, are shown in Table 16.6. 

Fig. 16.19 GC-ECD chromatograms showing appearance of polybrominated diphenyl ether (PBDE) congeners, after sunlight irradiation of BDE-209 (retention time = 88.7 min) adsorbed on montmorillonite, at different times. Reprinted with permission from Ahn MY, Filley TR, Jafvert CT, Nies L, Hua I, Bezares-Cruz J (2006) Photodegradation of decabromodiphenyl ether adsorbed onto clay minerals, metal oxides, and sediment. Environ. Sci. Technol. 40 215-220. Copyright 2006. American Chemical Society...

Similar effects were observed with sunlight-irradiated, diluted auto exhaust, which contains NOx (NOx = NO + N02) and a variety of hydrocarbons (HC)... 

Photochemically induced ring enlargements of alk-l-enylcyclobutanes to cyclohexenes have been reported only in a few select examples. A steroidal cyclohex-3-enone was formed in an equilibrium reaction from a 2-alk-l-enylcyclobutanone precursor.84 With a cyclohex-2-enone only the reverse reaction, i.e. ring contraction to give a cyclobutanonc, was observed.85 86 In a tricyclic system, a [1,3] shift occurred on sunlight irradiation to form a cyclohexene in 90% yield from an alk-l-enylcyclobutane.87... 

When azirenoimidazoles were first synthesized [88] their photochromic properties were discovered all the crystalline 6-(4-nitrophenyl)-substituted aziridines, colorless or yellowish, became deep blue upon sunlight irradiation the coloration disappeared in a few days in the dark. Photochromism was also observed for azirenoimidazole hydrochlorides. Their crystals became red upon irradiation. Photochromic properties were also found for azirenoimidazoles without a nitrophenyl group on the aziridine cycle but they were much less pronounced. 

Shiroishi and Hayakawa (18) have described the effect of sunlight irradiation on pyridoxine and related compounds in aqueous solution at various pH s. Pyridoxine and pyTidoxamine are relatively stable in acidic medium, while pyridoxal decomposes independently of pH. The authors suggested that the aldehydic 0 participates in the photolysis of pyridoxal. The presence of Cu++ had no effect on the stability of these substances. A borate complex of pyridoxine is stable to sunlight irradiation, heating, or autoclaving. Acetic acid and a reddish brown substance were separated as the decomposition products from an irradiated solution of pyridoxine (18). 

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