37
GREEN SYNTHESIS AND RESEARCH OF SURFACTANTS AND THEIR APPLICATION
AREAS IN VARIOUS DIRECTIONS
1,2
Zarbaliyeva Ilhama Agalar -
1
Doctor of Chemical Sciences, Associate Professor, Chief Scientific
Researcher of the Institute Petrochemical Processes of Ministry of Science and Education of
Azerbaijan
2
Professor of "Food Engineering" specialty of SABAH Faculty of the Azerbaijan Economical
University (UNEC)
1
Alimova Amina Nadir
-
1
Post-graduate student
of the Institute Petrochemical Processes of Science
and Education of Azerbaijan
1
Nabiyeva Hajar Tahir -
1
Post-graduate student
of the Institute Petrochemical Processes of Science
and Education of Azerbaijan
3
Abilhasanli
Rasul Elcin,
2nd-year master's student of Azerbaijan University of Oil and Industry
Surface-active substances find a wide application in all branches of the national economy
[1,2]. Especially, the surfactants produced from environmentally -safe and reproducible initial
materials attract the attention of specialists [3-4]. This paper is devoted to the obtainment of new
representatives of such reagents and an investigation of their antimicrobial activity.
Aminoester was prepared based on fatty acids and bis(2-hydroxyethyl)(methyl)amine by
heating at 140-150
o
C during 13-14 hours in an autoclave equipped with a temperature regulator.
Subsequently, phosphating of the obtained aminoester was performed by the interaction of the
aminoester with orthophosphoric acid at 50-60
o
C during 5-6 hours.
The scheme of the reaction of fatty acids with bis(2-hydroxyethyl)(methyl)amine is depicted
below:
R
O
O
C H
3
R
R
O
C H
2
C H
2
O H
O
C H
3
C H
2
- O - C
C H - O - C
C H
2
- O - C
3 R -C
O C H
2
C H
2
- N - C H
2
C H
2
O H
+ 3 N - C H
2
C H
2
O H
C H
2
- O H
C H - O H
C H
2
- O H
+
where R is alkyl group. Glycerol was removed from the final mixture applying washing
procedure with cold water. The isolated aminoester is soluble in water and kerosene.
In the next step, the obtained bis(2-hydroxyethyl)(methyl)amine ester was phosphated using
orthophosphoric acid. The chemical formula of the synthesized surfactant is illustrated as following:
H O
O
C H
3
R -C
O - C H
2
C H
2
- N - C H
2
C H
2
O -P (O H )
-
+
where R is a saturated or unsaturated hydrocarbon group. The final product is a brown substance of
low viscosity.
Both the aminoester and its phosphate surfactants are viscous liquids of brown color.
Structure and composition of the obtained products were confirmed by means of IR-
spectroscopy.
Bis(2-hydroxyethyl)(methyl)amine ester and its phosphate have good solubility in
isopropanol, isooctane, kerosene, benzene, carbon tetrachloride, a partial solubility in ethanol and
water.
Surface tension data of the synthesized surfactants 1and 2 were obtained at 25 and 26
o
C,
respectively,
versus concentration (-c ) of the surfactants.
Based on these isotherms, the main parameters of the surface activity may be determined.
The values of critical micelle concentrations (CMC) of the surfactants were found. Moreover,
CMC
,
surface pressure (π
CMC
), C
20
(the concentration for reducing
by 20 mN/m), adsorption efficiency
(
) values for the surfactants were calculated according to [4]
38
Maximum adsorption-
values were calculated according to the following equation:
where R is universal gas constant (R=8.3145 C/mol*K) and T is absolute temperature. The value of
n was taken as 2 because dissociation of the surfactants (explained later) molecules leads to
formation of 2 ions.
The minimal value of the area per surfactant molecule after adsorption at the water-air
interface (A
min
) was calculated by the equation
Specific electrical conductivity versus concentration plot was built for bis(2-
hydroxyethyl)(methyl)amine
ester
at
27
o
C
and
for
the
phosphate
of
bis(2-
hydroxyethyl)(methyl)amine ester at 27.5
o
C.
Slopes of the straight line before (S
1
) and after (S
2
) CMC value for both surfactants were
determined. Such important thermodynamic parameters as Gibbs free energy of micellization
(ΔG
mic
) and Gibbs free energy of adsorption (ΔG
ad
) values were determined from the following
equations:
where
is surface area per surfactant molecule at the interface in terms of Å
2
.
A degree of dissociation – α and a degree of the counter-ion binding –β were computed
using the formulas:
α= S
2
/S
1
and
β=1-α
As is seen, the ΔG
ad
values are more negative than the ΔG
mic
values that points out to a
preference of the adsorption of the surfactant molecules over their micelle formation.
In addition to having high surface-active properties of the synthesized reagents, their
petrocollecting and petrodispersing, as well as antimicrobial and anti-corrosion abilities have also
been proven through laboratory experiment.
References
[1]. H.H.Humbatov, R.A.Dashdiyev, Z.H.Asadov et.al. Chemical Reagents and Petroleum
Production, Baku:Elm, 2001,448 pp.
[2]. Z.H. Asadov. New petroleum-collecting and petroleum-dispersing surfactants based on
ecologically-clean and reproducible kinds of feedstock
Azerbaijan oil industry
. 2009, №2, p. 60-
65.
[3]. M.J.Rosen. Surfactants and Interfacial Phenomena, 3
rd
Edn.NewYork:JohnWiley and
Sons, Inc. 2004,444 pp.
[4]. Lange K.P. Surface- active substances . Sankt-Petersburg: Professiya, 2005. 239p.
