ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 12, pp. 2039 2040.
Pleiades Publishing, Inc., 2006.
Original Russian Text
R.I. Yurchenko, T.N. Pilipenko, M.A. Yurchenko, T.I. Krivovyaz, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79,
No. 12, pp. 2063 2064.
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COMMUNICATIONS
Protective Effect of 1-Benzyl-2-R-Pyridinium Halides
in Steel Acid Corrosion
R. I. Yurchenko, T. N. Pilipenko, M. A. Yurchenko, and T. I. Krivovyaz
Kievskii Politekhnicheskii Institut National Technical University of Ukraine, Kiev, Ukraine
Received September 4, 2006
Abstract The inhibiting effect of 1-benzoyl-2-R-pyridinium halides on the acid corrosion of steel was
studied and compared with that of 1-phenacylmethyl-2-R-pyridinium halides.
DOI: 10.1134/S1070427206120299
Previously, using a fairly large data set, we have
considered the correlation between the nature of sub-
stituent R in 1-phenacylmethyl-2-R-pyridinium bro-
mides (I) and their protective properties in steel acid
corrosion [1 3]. The coefficients of corrosion inhibi-
tion for these compounds range from 10 to 40 at room
temperature and may reach almost 900 at 60 C [2].
We assumed that the major factor responsible for
the corrosion inhibition may be adsorption of the car-
bonyl group of the phenacyl fragment and probably of
substituents in the pyridinium ring. In order to confirm
the decisive role of the carbonyl groups of I at elevated
temperatures and to clarify the role of R, we studied
protective properties of 1-benzyl-2-R-pyridinium ha-
lides (II, II ) in the steel acid corrosion and compared
them with the properties of 1-phenacylmethyl-2-R-
pyridinium bromides (I) with the same R:
where X = Cl (II), R = H (a), NH2 (b),
NHCOCH=CHPh (c), NHCO-furyl-2 (d), NHCOAd-1
(e), NHCSNHPh (f); X = Br (II ), R = CH3 (a) and
NH2 (b).
EXPERIMENTAL
Corrosion tests were performed by the conventional
procedure [1] with samples of 08 KP steel with
4
a working surface area of 14 10 m2. The sam-
ples were kept in 3 M H2SO4 at 20 C for 24 h and
at 60 C for 2 h. The efficiency of steel protection
with substances synthesized at their concentration of
2
1
10 M was evaluated by the inhibition coefficient
and degree of protection Z.
We found that, at 20 C, benzylpyridinium bro-
mides (II a, II b) and the corresponding 1-phenacyl-
methylpyridinium bromides (Ia, Ib) differ only slight-
ly in , but this difference becomes more substantial
with increasing temperature. At 60 C, is 209 and
200 for Ia and Ib and 25.19 and 32.81 for II a and
II b, respectively (Table 1).
+
-- N
+
N
R
R
Br
X --
CH2C(O)Ph
CH2Ph
II, II
I
A comparison of the inhibiting effects of 1-ben-
zyl-2-R-pyridinium chlorides, bromides, and the cor-
responding phenacylmethylpyridinium bromides I
showed that, at room temperature, replacement of chlo-
ride with bromide, variation of the substituent R in
the 2-position of the pyridine ring, and passing from
1-benzyl-2-R-pyridinium bromides to phenacylmeth-
ylpyridinium bromides do not substantially change
the protective properties of the pyridinium salts (Ta-
ble 2). For example, the inhibition coefficient varies
within the range of 6 units for compounds II and II ,
where X = Cl (II), Br (II )
By alkylation of the corresponding pyridine deriv-
atives with benzyl chloride, we synthesized 1-benzyl-
R-pyridinium chlorides (II, X = Cl). The subsequent
treatment with an alcoholic solution of KBr yielded II
R
R
N
N
+
+
Cl
X
2039