Dichlorotoluene Essay

The dichlorotoluenes are halogenated VOCs that can be directly emitted into the atmosphere from industrial processes or be released through combustion chemistry at incinerator sites. They can also be released in the environment through waste water used during production. They are mainly used as intermediates in the manufacture of fungicides, dyes, pharmaceuticals, preservatives, and peroxides. In a survey sponsored by USEPA of 4000 industrial and publicly owned treatment works, two of the dichlorotoluene isomers (2,6-dichlorotoluene and 2,4-dichlorotoluene) were identified in the discharges into water from rubber processing (1 occurance, 314.9 ppb), organic chemical synthesis (14 occurances, 26.7 ppb), and publicly owned treatment works (5 occurances, 40.4 ppb) (Howard, 1997). The highest effluent concentration reported was 1424 ppb in the paint and ink industry (Howard, 1997). When released in the atmosphere, the dichlorotoluenes should degrade by reaction with hydroxyl radicals with a half-life of about 12 days (Howard, 1997), which is significantly longer than the estimated lifetime for toluene of 2 days (Finlayson-Pitts and Pitts, 2000). Their estimated half-lives
They were mainly chosen for this study, to test a previously proposed theory for the monosubstituted chlorotoluenes, important environmental halogenated pollutants, that have been recognized as possible precursors leading to the formation of PCDD/Fs. Based on theoretical calculations, Dadson proposed that the main factor contributing to the larger rate constant for the para-chlorotoluene in comparison to the ortho- and meta- isomers is the higher internal rotational symmetry of the methyl group of the para- substituted isomer (Dadson, 2005). In this work, the two difluorotoluene isomers with higher internal rotational symmetry are those with fluorine atoms in ether the two ortho positions or the two meta