Pyrazolones titration

Various aromatic amines, phenols, and compounds containing active methylene groups can be titrated with arenediazonium salts, from which 4-bromo-l-naphthale-nediazonium chloride seems to be the most widely applicable titrant. Compounds that react slowly with arenediazonium salts can be determined by back-titration when the excess of arenediazonium salt is back-titrated with either sodium tetraphenylborate or 2,4-diaminotoluene. Indirect determination is useful for secondary amines, which react with arenediazonium ions to form triazenes. The determination of diazonium salts of ampholytic character is based on the reaction of these salts with l-phenyl-3-methyl-5-pyrazolone, the excess of which is titrated with 4-bromo-l-naphthalenediazonium chloride solution. 

BIOLOGICAL PROPERTIES Koc 1-70 for most soluble forms at pH less than 9.2, most free cyanide is expected to convert to HCN highly volatile and biodegradable when released to water have the potential to leach into groundwater do not adsorb to soil nitriles have the highest mobility in soil can be detected in water by silver nitrate titration or colorimetric analysis using pyridine pyrazolone... 

Reaction of phenylhydrazine with the j8-keto ester (64) gives the pyrazolone (65). The hydantoin (66) has been obtained by the action of potassium cyanide and ammonium carbonate on ferrocenecarbox-aldehyde. The potentiometric titration of hydantoin (67) has been reported. 

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