Chlorophenyl .l 1 1-trichloroethane

The name D.D.T. is derived from dichlorodiphenylfrichloroethane this is a misnomer since the name represents 27 different compounds. As commonly employed it refers to 2 2-6ts(p-chlorophenyl)-l 1 1-trichloroethane. It is conveniently prepared by the condensation of chlorobenzene and chloral hydrate in the presence of concentrated sulphuric acid ... 

Fig. 2 Molecular structures of the Dirty Dozen. 1 - Polychlorinated dibenzo-p-dioxines, PCDD 2 - Polychlorinated dibenzofuranes, PCDF 3 - Polychlorinated biphenyls, PCB 4 - Hexachlorobenzene, HCB 5 - 2,2-Bis(4-chlorophenyl)-l,l,l-trichloroethane, DDT 6 - Toxaphene 7 - Aldrin 8 - Dieldrin 9 - Endrin 10 -Chlordane 11 - Heptachlor 12 - Mirex.

SYNONYMS agritan, azotox, 2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane, chloro-phenothane, ddt, dicophane, diphenyltrichloroethane, gesapon, gesarol, ixodex, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane. 

DDT is an acronym for dichlorodiphenyl trichloroethane, but should be named more precisely as 2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane (see Fig. 16.1 for its structure). A German chemist, Othmar Zeidler synthesized this compound in 1874 while he was pursuing his PhD. And it had remained as that, a new synthesized compound, for a quite while. Carl Muller of J. R. Geigy (a Swiss Pharmaceutical company, now Chiba-Geigy) discovered in his pursuit of insecticides that the compound synthesized by O. Zeidler was extremely toxic to houseflies. Numerous tests were conducted, and the compound DDT was found to be an excellent insecticide. Besides it is cheap to make. This was the time when the World War II was raging. DDT was then used to control lice on soldiers on the front. In earlier wars, more soldiers died of typhus (bom by louse) than by bullets. The WWII was really the first war in history where more soldiers died actually from bullets than the louse-bom disease, thanks to DDT. DDT was then considered to be a savior to control many kinds of harmful pests. C. Muller was awarded a Nobel prize in 1948. 

Nitration of DDT and its dehydrochlorination product 1,1 -dichloro-2,2-di-(4-chlorophenyl)-ethylene led to the formation of bis(3-nitro-4-chlorophenylene) compounds containing 1,1,1-trichloroethane and carbonyl bridging groups [19,20]. These compounds were converted to the corresponding bis(3-amino-4-chlorophenylenes) l,l-dichloro-bis-(3-amino-4-chlorophenyl)-ethylene and 3,3 -diamino-4,4 -dichlorobenzophenone in accordance with Scheme 2.9 [5, 22, 24]. 

A study showed that the level of pesticide contamination of milk produced in the Arizona milkshed was somewhat higher than in most other states. It fluctuated on a seasonal cycle with a low of about 1.0 p.p.m. of pesticide in the milk fat in the late spring and early summer months and a high of 3.0. to 3.5 p.p.m. in the late fall and early winter months. The pesticides found in the milk were predominantly DDT [2,2-bis- (p-chlorophenyl) -1,1,1-trichloroethane] and its metabolites DDD [2,2-bis- (p-chlorophenyl)-l,l-dichloroethane] and DDE [2,2-bis-(p-chlorophenyl) -1,1-dichloroethylene]. The metabolite DDE was generally present in 5-10 times greater amounts than DDT or DDD. The insecticide /J-BHC was encountered occasionally at very low levels (<0.2 p.p.m. in milk fat), and other insecticides were encountered sporadically when related to a particular instance of misuse. 

DDT (2,2-bis (p- chlorophenyl)- 1,1,1-trichloroethane Cl L. <> Cl Pesticide Unselective poison, concentrates up food chain... 

However, Teltow Canal sediments are not only contaminated by DDT and its metabolites (2,2-bis(chlorophenyl)-l,l-dichloroethane - DDD, 2,2-bis(chlorophenyl)-1 -chloroethane DDMS, 2,2-bis(chlorophenyl)-l, 1 -dichloroethene - DDE, 2,2-bis(chlorophenyl)-l-chloroethene DDMU, l,l-bis(chlorophenyl)ethene DDNU, l,l-bis(chlorophenyl)ethane - DDEt, bis(chlorophenyl)methane - DDM, 2,2-bis(chlorophenyl)acetonitrile DDCN) but also by halogenated aromatics and additional pesticides (e.g. bromonaphthalenes, tribromoanilines, the acaricide 2,2-bis(4-bromophenyl)-2-hydroxyacetic acid /.vo-propylcstcr - bromoproylate and the insecticide 2,2-bis(methoxyphenyl)-1,1,1-trichloroethane... 

BIS (p-CHLOROPHENYL)-2,2,2-TRICHLOROETHANE or 2,2-BIS (p-CHLOROPHENYL)-l,l-TRICHLORO-ETHANE or 2,2-BIS (p-CHLORO-PHENYL)-l,l,l-TRICHLOROETHANE or ,a-BIS (p-CHLOROPHENYL)-/ ,/ ,/ -TRICHLORETHANE (50-29-3) C14H9CI5 Combustible solid (flash point 324 to 340°F/162 to 171°C). Incompatible with strong oxidizers reducing agents, including metal hydrides, nitrides, sulfides, alkali metals, and metal alkyls ferric chloride aluminum chloride salts of iron or aliuniniun alkalis and alkaline media. May be incompatible with many alkali metals ... 

This narrow range of restriction in the physical size of the active DDT-type molecule is supported by the relative inactivity of 2,2-bls-( -chlorophenyl)-l,l,l-tribromomethane (Musca 500, Culex 0.55) where the van der Waals radius of -CBr3 is 3.21 A° and by comparison of 2,2-bis-( -chlorophenyl)-2,l,l,l-tetrachloroethane (completely inactive) vs. 2,2-bi -( -chlorophenyl)-2-fluoro-l,l,l-trichloroethane (Musca 125, Culex O.C ) where the atomic radius of F is 1.47 A compared to 1.75 A for Cl. With decreased crowding around the -carbon, using 2,2-bls-( -chlorophenyl)-l,l-dichloroethane as a model ( (Musca 19.7, Culex 0.038), insertion of of-F (7) substantially Improved toxicity (Musca 4.1. Culex 0.024), insertion of e>c-Cl (8) is acceptable (Musca 18.5, Culex 0.24, and toxicity is further decreased withOf-Br (2,2-bis- -chlorophenyl)-2-bromo-... 

---