ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 6, pp. 1078!1080. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + M.D. Vedenyapina, E.D. Strel
tsova, A.K. Rakishev, A.A. Vedenyapin, 2008, published in Zhurnal Prikladnoi Khimii,
2008, Vol. 81, No. 6, pp. 1039!1041.
Hydrolysis of Acetylsalicylic Acid under the Conditions
M. D. Vedenyapina, E. D. Strel
tsova, A. K. Rakishev, and A. A Vedenyapin
Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
Received July 21, 2008
Abstract-The hydrolysis of acetylsalicylic acid in the anolyte under the conditions of electrolysis was
Acetylsalicylic acid (ASA, Aspirin
) is one of
the most popular drugs which, together with other
drugs, gets into wastewater, and hampers operation
of biological sewage treatment plants [1, 2]. It is
known that the biological activity of ASA-contain-
ing aqueous solutions can be decreased by more
than an order of magnitude by their electrooxida-
tion . However, it remains unknown whether
ASA itself or its hydrolysis product, salicylic acid
(SA), undergoes electrooxidation. To answer this
question, we compared in this study the ASA anod-
ic oxidation kinetics, on the one hand, and the ASA
hydrolysis kinetics under electrolysis and without
it, on the other hand.
The ASA hydrolysis was studied in 0.1 N aqu-
at room temperature. The ASA and
SA anodic oxidation was carried out at 25oCin
a two-electrode electrochemical cell with a mem-
brane separating the anode and cathode chambers.
A smooth platinum plate was used as anode.
The current density was 10 mA cm
. The anolyte
was analyzed by high-performance liquid chro-
matography (HPLC) and UV spectroscopy.
We found that, on keeping ASA in aqueous
without electrolysis, the absorption band
in its UV spectrum at 227 nm is shifted to 235 nm.
This means that, under these conditions, ASA is
hydrolyzed to form SA. This conclusion is con-
sistent with Fig. 1 showing that, as the SA/ASA
ratio in their mixtures increases, the absorption
band at 227 cm
linearly shift to longer wave-
lengths. From this correlation, we determined the SA
content of the ASA3SA mixtures in the course of
ASA hydrolysis. We found that the ASA hydrolysis
is relatively slow and a 90% degree of hydrolysis
is reached only in 16 days (Fig. 2). The time de-
pendence of the SA content of the reaction mixture
Fig. 1. Position of the maximum of the absorption band
in the UV spectrum of ASA!SAsolutions in 0.1 N
vs. ASA content O.
Fig. 2. Dependence of the ASA concentration ? on hy-
drolysis time J in aqueous H