1070-4272/01/7403-0427$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 3, 2001, pp. 427! 429. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 3,
2001, pp. 419!421.
Original Russian Text Copyright + 2001 by Yurkinskii, Sokolova, Popov.
AND CORROSION PROTECTION OF METALS
Effect of Lead(II) Complexation on Solubility of >-PbO
in Alkaline Solutions in the Presence of Certain Alcohols
V. P. Yurkinskii, N. V. Sokolova, and V. A. Popov
St. Petersburg State Technical University, St. Petersburg, Russia
Received September 9, 1999; in final form, November 2000
Abstract-Complex formation of lead(II) was studied, and the solubility of b-PbO was determined by
potentiometric titration in solutions containing sodium hydroxide (0.33 4 M) and a series of mono- and poly-
hydric alcohols. A correlation between the lead monoxide solubility and Pb(II) complex formation function
The major fraction of the secondary lead raw ma-
terial is lead(II) oxide. Its processing involves treat-
ment with alkaline solutions in which fairly high
solubility of PbO is caused by formation of strong
Pb(II) hydroxo complexes . To increase the
PbO solubility, it is suggested to add alcohols (e.g.,
glycerol ) into the alkaline solution.
In this work, the solubility of b-PbO in alkaline
solutions containing additives of mono- and poly-
hydric alcohols (1-propanol, ethanol, ethylene glycol,
glycerol, and sorbitol) was determined. Simultaneous-
ly, complex formation of Pb
ions in these solutions
was studied to determine the correlation between the
PbO solubility and the lead(II) complex formation
To determine the complex formation function, we
used potentiometric titration [2, 3].
It is known that in alkaline solutions Pb
form strong complexes, mainly Pb(OH)
To determine the composition of lead(II) hydroxo-
alcoholic complexes, we used a method developed by
us previously for studying complex formation of
Pb(II) in alkaline solutions with glycerol . The
average ligand number n in the complex was deter-
mined as a slope of the linear dependence of the in-
dicating lead amalgam electrode on the logarithm of
the ligand (hydroxide ion, alcohol) concentration .
are listed in the table.
is close to 3 for all alcohols, similar-
ly to glycerol . Hence, complexes Pb(OH)
in the solution . The n
value shows that the
Pb(II)-to-alcohol ratio is 1 : 1 for sorbitol and 2 : 1 for
the other alcohols.
Thus, the composition of the prevailing complexes
in the solution can be presented by the formula
for sorbitol and [2Pb(OH)
for the other alcohols.
Using the known equation 
DE = ÄÄÄ lnÄÄÄÄÄ = ÄÄÄlnF,
where DE is the experimental difference between
potentials of the indicating electrode in the initial
solution and in the solution containing sodium hy-
droxide, we calculated the complex formation func-
tion F as influenced by the hydroxide ion concentra-
tion for all the solutions studied.
Then, the functions F were obtained for solutions
with fixed [OH
] and variable concentrations of al-
cohols. In Fig. 1, these dependences are shown for
] = 0.3 M. For the other sodium hydroxide con-
centrations such dependences are similar.
The presence of 1-propanol or ethanol in alkaline
solutions changes the lead(II) complex formation
function weakly (by no more than 10%). As for ethyl-
Average number of ligands in lead(II) complexes
3 ³ 2.96 + 0.05 ³ 3
1-Propanol ³ 2.7+0.1 ³ 0.5+ 0.1
Ethanol ³ 2.7+ 0.1 ³ 0.5+0.1
Ethylene glycol ³ 2.8+0.1 ³ 0.5+ 0.1
Sorbitol ³ 3.0+ 0.1 ³ 1.0+0.1