Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 11, pp. 1993−1996.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
S.A. Kuznetsov, N.I. Kol’tsov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 11, pp. 1861−1864.
AND INDUSTRIAL ORGANIC CHEMISTRY
A Versatile Kit of Additives to Lubricating Oils
S. A. Kuznetsov and N. I. Kol’tsov
Ilya Ulyanov Chuvash State University, Federal State Educational Institution
of Higher Professional Education, Cheboksary, Chuvashia, Russia
Received January 26, 2010
Abstract—Various mixtures of imidazolines, copolymers of methacrylic acid esters, and trithiolanes were examined
as additives to motor oils for diesel fuels or to cutting ﬂ uids.
Improvement of the reliability and performance
of machines and mechanisms requires considerable
enhancement of service characteristics of fuels and
lubricating materials. One of the most important
characteristics of any lubricating material is long life
under the conditions of increased load. The extent of wear
can be reduced by adjusting the chemical composition
of oil and the content of surfactants determining the
strength of the lubricating ﬁ lm. To this end, antiwear and
antiscuff additives are introduced into motor oils . To
reduce the contamination of parts of various equipment
and engines with carbonaceous deposits, detergents and
dispersants are also added. When operating in engines
and mechanisms at high temperatures, lubricating oils
are in contact with air. Under these conditions, they
undergo oxidation with the formation of acidic products,
which favor corrosion of metallic parts and formation of
carbonaceous deposits, disturbing the normal functioning
of mechanisms. This factor restricts the life of lubricating
materials. The process can be prevented by introducing
into oils antioxidant additives . Some additives improve
simultaneously several properties of oils and are therefore
termed multifunctional. A topical problem for Russia and
CIS countries is the development of special formulations,
so-called kits of additives (KAs). The modern kits of
additives contain up to 15 components and are introduced
into oils in an amount of up to 12% of the total weight .
The versatile kit developed contains three major kinds
of additives: antioxidant, detergent and dispersing, and
lubricating additives. Cyclic imidazolines are used as
antioxidant additives. These compounds are prepared in
one step at normal pressure by the reaction of oleic acid
with triethylenetetramine or tetraethylenepentamine
in the presence of cation-exchange resins as catalyst.
The synthesis of imidazolines is performed with one
or two moles of the fatty acid, with the formation of
cyclic or bicyclic substituted imidazolines, respectively.
The compounds thus prepared are soluble in oils
owing to the lipophilic moiety and have low values of
the hydrophilic–lipophilic balance. This is extremely
important, allowing imidazolines to be used not only
as antioxidants but also as lubricating, emulsifying, and
corrosion-protecting (for nonferrous metals) additives
to oils and lubricants. The corrosion-protecting
properties of imidazolines toward nonferrous metals
were determined for their 1% solutions in 48-h tests .
To determine the resistance to oxidation, we prepared
0.5–2.0% solutions of imidazolines in I-20A industrial
oil. The results of studying these solutions following the
State Standard procedure  are given in Table 1.
As seen from Table 1, after the tests I-20A oil without
additives has the acid number of 1.45 mg of KOH per gram
of product, i.e., it is unsuitable for further use without
regeneration. Additions of imidazolines largely inhibit
the oxidation of industrial oil under the action of high
temperatures and atmospheric oxygen. The 2% solution
(Additive 1) in I-20A oil exhibits the best properties:
The oxidation resistance becomes eight times higher, as