INSECTICIDES AND REPELLENTS 



9 



1.57-1.67, is nearly insoluble in water, but is miscible or soluble in 

 all proportions in nearly all organic solvents and petroleum oils, 

 including refined kerosene. 



A closely related compound, heptachlor, was first isolated by a 

 process of chromatographic adsorption from technical chlordane. It 

 has a melting point of 92°-93° C, its molecular formula is Ci H 5 Cl 7 , and 

 its chemical name is 1 (or 3a),4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetra- 

 hydro-4, 7-methanoindene. It, too, is highly active insecticidally. 



The structural formulas of the two compounds are shown below. 



ci 



cci 2 



m 



X)|H 



CI 



Y HCl CI 



CI 



CC12 



CI 



C hlordane 



H |\ 

 CI H 



CI 



CI H |\ 

 X H 



Heptachlor 



Methods of Analysis 



The total-chlorine determination as used for DDT and benzene 

 hexachloride (see pp. 5 and 8) may also be used for chlordane and hep- 

 tachlor when present singly, although it must be kept in mind that this 

 is not a specific method. 



Chlordane reacts with diethanolamine in the presence of meth- 

 anolic potassium hydroxide, yielding a mixture of colored compounds. 

 The intensity of the overlapping colors may be determined at 550 

 millimicrons on a Beckman DU spectrophotometer. Heptachlor may 

 interfere with the determination of chlordane in this method. 



The reaction between heptachlor and potassium hydroxide, mono- 

 ethanol amine, and Butyl Cellosolve produces a pink to intense violet 

 complex that is specific for heptachlor in the presence of chlorinated 

 hydrocarbons other than technical chlordane. The intensity of color 

 is suitable for use in analvsis. 



DIELDRIN AND ALDRIN 

 Properties 



Dieldrin and aldrin were developed in 1948. They are whitish 

 crystalline solids and are highly active insecticidally. Dieldrin, which 

 is an oxygenated derivative of aldrin, is the more toxic to most insects, 

 and its insecticidal action is more persistent. It has been superior to 

 aldrin for controlling many of the insects affecting man. The chemical 

 names, molecular formulas, and melting points of the pure compounds 

 are as follows: 



Dieldrin. 1,2,3,4, 10, 10-hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8a-octa- 

 hydro-l,4,5,8-dimethanonaphthalene; d 2 H 8 Cl 6 0; m. p. 172°-175° C. 



Aldrin. 1,2,3,4, 10, 10-hexachloro-l ,4,4a, 5,8, 8a-hexahydro-l,4, 5,8- 

 dimethanonaphthalene; Ci 2 H 8 Cl 6 ; m. p. 100°-103° C. 



The structural formulas are shown below. 



h ci 



cci 2 



r.ci 



Jci 



ch 2 



H H Cl 



Dieldrin 



('! 



CClo 



H H 



Aldrin 



