1,4-dichlorobenzene environmental fate

Physical and Chemical Properties. The physical and chemical properties of 1,4-dichlorobenzene are sufficiently well characterized to allow estimation of its environmental fate (Amoore and Hautala 1983 Chiou et al. 1983 Howard 1990 Tide and Frederikse 1994 Newsom 1985 NFPA 1994 Sax and Eewis 1987 Schwarzenbach and Westall 1981 Verschueren 1983 Wilson et al. 1981). On this basis, it does not appear that further research in this area is required. 

Environmental Fate. The environmental fate of 1,4-dichlorobenzene has been well characterized. 

Howard PH. 1989. 1,4-dichlorobenzene. Handbook of environmental fate and exposure data for organic chemicals. 1 250-262. 

PROBABLE FATE photolysis, expected to oecur slowly oxidation no data available on aqueous oxidation, oxidized by hydroxyl radicals in atmosphere hydrolysis not important process first-order hydrolytic half-life >879 yrs volatilization volatilizes at a relatively rapid rate, half-life is about 10 hr volatilization from soil surfaces is expected to be a signifieant transport mechanism sorption sorbed by organic materials adsorption to sediment expected to be a major environmental fate process based on research in the Great Lakes area biological processes bioaccumulates more than chlorobenzene, biodegradation is not as significant as volatilization slightly persistent in water, half-life 2-20 days approximately 98.5% of 1,3-dichlorobenzene ends up in air 1% ends up in water the rest is divided equally between terrestrial soils and aquatic sediments. 

Dichlorobenzene will exist predominantly in the vapor-phase in the atmosphere, and its detection in rainwater suggests that atmospheric removal via washout is possible (Ligocki et al. 1985). Depending on soil type, the compound is expected to be moderately mobile in soil and to volatilize from surface water and soil surfaces to the atmosphere. Volatilization, sorption, biodegradation, and bioaccumulation are likely to be competing processes, with the dominant fate being determined by local environmental conditions. 

A colleague of yours who investigates the fate of benzene sulfonates and benzene sulfonate esters in natural waters is interested in the stability of methyl-3,4-dichlorobenzene sulfonate (MDCBS) in aqueous solution. Because he has not read Chapter 13 of Environmental Organic Chemistry he asks you to help him to estimate the hydrolysis half-life of this compound in water at 25 °C and at 5°C. In the literature you find rate constants for the neutral hydrolysis of some substituted methyl benzene sulfonates at... 

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