Methanol photolytic degradation

Polybrominated Biphenyls. The photolytic degradation of PBBs in solution has been the subject of several studies. Available data in the literature indicate that brominated biphenyls photodegrade by reduction in solvents capable of proton transfer with the formation of lower brominated biphenyls. For example, the irradiation of FireMaster BP-6 and 2,2, 4,4, 5,5 -hexabromobiphenyl in methanol at wavelengths >286 nm produced mainly penta- and tetrabromobiphenyl (Ruzo and Zabik 1975). FireMaster BP-6 photolyzed7 times faster than its chlorinated counterpart, 2,2, 4,4, 5,5 -hexachloro-biphenyl (Ruzo and Zabik 1975). Although an earlier study tentatively identified dimethoxy tetrabromobiphenyl as a photolysis product of FireMaster BP-6 (Ruzo and Zabik 1975), later work did not detect this compound (Ruzo et al. 1976). Earlier studies indicated that the debromination usually occurs with the stepwise preferential loss of bromine from the ortho and para positions of the biphenyl ring (i.e., 2, 2, 6, and 6 positions) (De Kok et al. 1977 Ruzo and Zabik 1975 Ruzo et al. 1976 Trotter 1977). Thus, the photolysis of 2,2, 4,4, 5,5 -hexachlorobiphenyl, the major component of FireMaster BP-6, would be expected to produce 23, 4,4, 5-pentabromobiphenyl and subsequently... 

A concentrated DCM solution of photolytically degraded PBO was spotted onto a silica thin-layer chromatography (TLC) plate and chromatographed using 20% ethyl acetate in DCM. The most intense coloured band (red/pink close to the origin) was scraped from the plate and eluted from the silica with methanol. 

H. Okada, V. Stella, J. Haslam, mid N. Yata, Photolytic degradation of a-[(dibutylamino)methyl]-6,8-di-chloro-2-(30, 4 -dichlorophenyl)-4-quinoline methanol An experimental antimalarial, J. Pharm. Sci. 64, 1665-1667 (1975). 

The Ir(V) tetrahydride 322, Ir(II) carbonyl-dihydride 323 and their fully deuterated congeners have also been encountered as the result of photolytic degradation of methanol by Tp IrH2(f/ -COE) (207) and Tp Ir(f/ -1,5-COD) (179). The latter has also served as precursor to 207 under high-pressure hydrogenation (500 atm), while at lower pressure (200 atm) the related dihydride Tp IrH2(i/ -l,5-COD) (209) is instead obtained. 

Photolytic. p-Nitrophenol and paraoxon were formed from the irradiation of parathion in water, aqueous methanol and aqueous w-propyl alcohol solutions by a low-pressure mercury lamp. Degradation was more rapid in water than in organic solvent/water mixtures withp-nitrophenol forming as the major product (Mansour et al., 1983). When parathion in aqueous tetrahydrofuran or ethanol solutions (80%) was irradiated at 2537 A, 0,0,S-triethylthiophosphate formed as the major product (Grunwell and Erickson, 1973). Minor photoproducts included 0,(9,(9-triethylthiophosphate, triethylphosphate, paraoxon and traces of ethanethiol and / -nitrophenol. 

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