T. Iwamoto
May 1, 1961
Citations
0
Influential Citations
50
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
Acid dissociation stages of analytical reagent 4-(2-pyridylazo)-resorcinol (PAR) and metal chelate formation of PAR were investigated by absorption measurements and pH-titrations. The first acid dissociation constant was determined as 1.48×10−6 (pka1=5.83) and the second as 3.2×10−13 (pka2=12.5) at 25°C. PAR forms 1 : 2 chelate with Fe(III), Co(II) and Ni(II), and forms 1:1 chelate with Cu(II), Zn(II), Cd(II), Hg(II) and Pb(II). The stability constant of copper(II)-PAR chelate was determined as 5×1011 at 25°C. Some analytical aspects of PAR were also discussed.