Determination of susceptibility of S-triazine herbicides to protonation and hydrolysis by mineral surfaces.
The relative ease of protonation and/or hydrolysis of s-triazine herbicides due to reactions on soil mineral surfaces may be measured by exposure of films of calcium-saturated montmorillonite to chloroform solutions of the s-triazines for appropriate time periods. s-Triazines susceptible to protonation are transformed into organic cations and adsorbed into the interlamellar region of the montmorillonite. Upon interlamellar adsorption of the s-triazine the concentration becomes sufficiently high to be detected by infrared techniques in the 1500 to 1800 cm-1 region. Hydrolysis of the triazines due to the "surface acidity" of the mineral surface is indicated by formation of a carbonyl band having a frequency at about 1750 cm-1. The relative degree of protonation and hydrolysis has been measured for twenty-seven chloro-, bromo-, methoxy-, and methylthio-s-triazines. These observations aid in predicting physiochemical behavior of s-triazines in soils as well as formulations containing similar mineral surfaces.
D001546:Bentonite; D001966:Bromine; D002118:Calcium; D055598:Chemical Phenomena; D002621:Chemistry; D006540:Herbicides; D006868:Hydrolysis; D008903:Minerals; D011522:Protons; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D014227:Triazines
D006540:Herbicides; D008903:Minerals; D011522:Protons; D014227:Triazines; D001546:Bentonite; D001966:Bromine; D002118:Calcium