ACID-BASE BEHAVIOR OF THE HERBICIDE PYRAZON - A SPECTROSCOPIC AND POLAROGRAPHIC STUDY

Infrared spectroscopic studies revealed that the herbicide Pyrazon (5-amino-chloro-2-phenyl-3(2H)-pyridazinone) is in acid-base equilibrium with a form produced by acid hydrolysis of the > C = N- bond, which in turn involves the reversible opening of the pyridazine ring. The acid-base constant of this equilibrium could not be calculated by spectroscopic or potentiometric methods; the polarographic dissociation constant, pK'(a), could only be determined by polarographic studies in different buffers.