27 

 fields could be selectively killed without injury to adjacent cereal 

 crops. Herbicidal effects of 2,4-D were described by F. D. Jones in 

 U. S. Patent No. 2,390,941 and this patent was assigned to the American 

 Chemical Paint Company (Weed Science Society of America, 1979). Black 

 and Buchanan (1980) credit recognition of the herbicidal properties 

 of 2,4-D as the catalytic discovery which led to development of many 

 chemically related herbicides and to development of weed control as 

 a scientific discipline. 



Physical and Chemical Characteristics 



Commercial concentrates of 2,4-D are generally formulated as salts 



or esters. The pure acid is a white, odorless crystal with a molecular 



weight of 221 and a molecular formula of CgHgC^Oo (Weed Science Society 



of America, 1979). According to the Weed Science Society of America 



(1979), the solubility of 2,4-D acid formulation in various solvents is 



as follows: 



Solvent g/lOOg solvent 



Acetone 85.0 



Diesel oil and kersosene 0.10 to 0.35 



Ethanol , 50 percent 10.3 



Ethyl alcohol, 95 percent 130.0 



Isopropanol 31.6 



Water 0.09 



The dimethyl amine salt formulation is extremely soluble, 300 g/lOOg of 

 water, soluble in alcohols and acetone, but insoluble in kerosene and 

 diesel oil. The butoxyethanol ester of 2,4-D is insoluble in water, but 

 soluble in most organic solvents. 



