Benzene, chlorination partial oxidation

Ozone can be used to completely oxidize low concentrations of organics in aqueous streams or partially degrade compounds that are refractory or difficult to treat by other methods. Compounds that can be treated with ozone include alkanes, alcohols, ketones, aldehydes, phenols, benzene and its derivatives, and cyanide. Ozone readHy oxidizes cyanide to cyanate, however, further oxidation of the cyanate by ozone proceeds rather slowly and may require other oxidation treatment like alkaline chlorination to complete the degradation process. 

Mutations at the active site of CYPlOl (cytochrome P450j,j jj) from a strain of Pseudomonas putida made possible the monooxygenation of chlorinated benzenes with less than three substituents to chlorophenols, with concomitant NIH shifts for 1,3-dichlorobenzene (Jones et al. 2001). Further mutations made it possible to oxidize even pentachlorobenzene and hexachlorobenzene to pentachlorophenol (Chen et al. 2002). Integration of the genes encoding cytochrome PTSO. into Sphingobium chlorophenolicum enabled this strain to partially transform hexachlorobenzene to pentachlorophenol (Yan et al. 2006). 

Triphenylbismuthine dichloride, ( 6115)361012/ occurs when chlorine is passed into a solution of triphenylbismuthine m ether, petroleum ether, chloroform or carbon tetrachloride. It crystallises in stout needles, M.pt. 126° C., soluble in alcohol, chloroform or benzene, practically insoluble in ether or petroleum ether. Moist silver oxide, alcoholic potassium hydroxide, potassium cyanate and other inorganic salts react with the dichloride giving varying yields of triphenyl-bismuthme. When a chloroform solution of the dichloride is treated with moist ammonia, one chlorine atom is removed and triphenylbismuthine hydroxychloride results. When the dichloride is added to concentrated sulphuric acid it yields triphenylbismuthine sulphate and hydrogen chloride is evolved. A dry benzene solution of the dichloride when boiled undergoes partial decomposition with formation of diphenyl-chlorobismuthinc. 

Tertiary treatment processes remove specific pollutants, including traces of benzene and other partially soluble hydrocarbons. Tertiary water treatment can include ion exchange, chlorination, ozonation, reverse osmosis, or adsorption onto activated carbon. Compressed oxygen may be used to enhance oxidation. Spraying the water into the air or bubbling air through the water removes remaining traces of volatile chemicals such as phenol and ammonia. 

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