68
NURULLINA et al.
concluded that the decomposition of hydroperoxide
occurs via the formation of a complex with the salt,
which complex is thermally less stable and easily
decomposes to give RO• and RОO• free radicals.
Thus, nonꢀtransition metals in their catalytic activity
are arranged in the order: Cd(EH)2 > Zn(EH)2 >
Hg(EH)2.
REFERENCES
1. L. V. Petrov, V. M. Solyanikov, and Z. Ya. Petrova, Dokl.
Akad. Nauk SSSR 230, 366 (1976).
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Zh. Prikl. Khim., No. 4, 701 (1980).
The catalytic functions of compounds of
Group IIA and IIB metals, which differ in electronic
structure and chemical nature are likely realized by
various mechanisms.
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st’, No. 7, 505 (1971).
Magnesium is markedly different from the IIB subꢀ
group metals by the atomic and ionic radii. Magneꢀ
sium exhibits stronger metallic properties, the formaꢀ
tion of covalent bonds is less typical of Mg than Zn or
Hg, and the formation of ionic bond is more typical.
In this regard, Mg is closer to Cd. The kinetic and
thermodynamic parameters of CHP decomposition in
the presence of magnesium 2ꢀethylhexanoate are
comparable in value to those for the Zn subgroup carꢀ
boxylates.
6. I. Drimus and A. Lupu, Rev. Roum. Chem. 17, 1409
(1972).
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cow, 1977) [in Russian].
In the complexes of Zn and Hg, the proportion of
covalency is high and these metals are less reactive, but
this bond is more ionic for active Cd; therefore, an
obvious conclusion is that the greater the stronger the
ionic character of the bond, the more active is the catꢀ
alyst. According to this conclusion, purely ionic Mg
complexes should surpass complexes of the zinc subꢀ
group metals in activity.
11. N. M. Nurullina, N. N. Batyrshin, and Kh. E. Kharꢀ
lampidi, Pet. Chem. 44, 441 (2004).
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sian].
However, it is the Zn subgroup metals that are
noted to exhibit a high catalytic activity [23], which is
undoubtedly due to the effect of additional polarizaꢀ
tion. Within the IIB subgroup, the catalytic properties
depend mainly on the nature of interaction forces actꢀ
ing during the formation of the ROOH–M intermediꢀ
ate (M = metal). As in the case of the main subgroup,
the bond for Cd compounds is determined mainly by
electrostatic factors. In the case of Zn and Hg, covaꢀ
lency plays an important role in the interaction. Howꢀ
ever, the reasons behind the tendency of Zn and Hg to
form covalent bonds are different: it is due to the addiꢀ
tional effect of polarization for Hg and to a small ionic
radius for Zn.
14. E. T. Denisov, Zh. Fiz. Khim., No. 8, 2085 (1964).
15. M. G. Bulygin and G. E. Zaikov, Izv. Akad. Nauk
SSSR, Ser. Khim., No. 3, 491 (1968).
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(Chernovtsy, 1986).
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Zh. Obshch. Khim., No. 7, 1636 (1974).
Thus, the overall decomposition of CHP mediated
by Mg carboxylate proceeds through the formation of
an intermediate activated complex, as in the case of
catalysis with Zn, Cd, or Hg 2ꢀethylhexanoate. The
kinetic and thermodynamic characteristics of the
CHP decomposition are close for Mg and Zn subꢀ
group metals. The catalytic activity of Mg 2ꢀethylhexꢀ
anoate in a CCl4 medium is higher than in chlorobenꢀ
zene and benzene. The stability of the complex,
depending on the solvent, decreases in the order
20. N. A. Sokolov and Yu. A. Aleksandrov, Usp. Khim.,
No. 2, 307 (1978).
21. A. Farkas and E. Passaglia, J. Am. Chem. Soc. 18, 999
(1950).
22. I. A. Suvorova, Candidate’s Dissertation in Chemistry
(Kazan, 2003).
23. S. K. Kozlov, F. I. Tovstokhat’ko, and V. M. Potekhin,
Zh. Prikl. Khim. 58, 2696 (1985).
C6H5Cl > CCl4 > C6H6
.
Translated by V. Makhaev
PETROLEUM CHEMISTRY Vol. 54
No. 1
2014