Synthesis and properties of mono or double long-chain alkanolamine surfactants

Article abstract of DOI:10.1007/s11743-013-1488-7

Two types of N-substituted long-chain alkanolamine surfactants were prepared. Firstly, octadecyl glycidyl ether was synthesized from octadecanol and epichlorohydrin. Subsequently, a ring-opening reaction of the epoxide ring of octadecyl glycidyl ether was performed with monoethanolamine and diethanolamine to synthesize bis(octadecyloxy)-2- hydroxypropylmonoethanolamine (D-MEA)and octadecyloxy-2-hydroxypropyldiethanolamine(M-DEA) without catalyst at 60 °C, respectively. And their corresponding tertiary amine salts bis(octadecyloxy)-2- hydroxypropylmonoethanolamine hydrochloride (D-MEAS) and octadecyloxy-2- hydroxypropyldiethanolamine hydrochloride (M-DEAS) were attained by neutralization with hydrochloric acid. The study on these four surfactants included their surface active properties, foaming abilities, emulsifying properties, lime-soap dispersion abilities and wetting abilities. The results show that D-MEAS possesses the best surface active property and lime-soap dispersion ability. D-MEA has better foaming ability and foaming stability. The wetting ability of M-DEA and the emulsifying property of M-DEAS are prominent.

Full text of DOI:10.1007/s11743-013-1488-7

J Surfact Deterg
DOI 10.1007/s11743-013-1488-7
ORIGINAL ARTICLE
Synthesis and Properties of Mono or Double Long-Chain
Alkanolamine Surfactants
•
•
•
Ya Zhang Yongshen Xu Shouji Qiu
Lei Yang
Received: 15 January 2013 / Accepted: 19 April 2013
Ó AOCS 2013
Abstract Two types of N-substituted long-chain alkanol-
amine surfactants were prepared. Firstly, octadecyl glycidyl
ether was synthesized from octadecanol and epichlorohydrin.
Subsequently, a ring-opening reaction of the epoxide ring of
octadecyl glycidyl ether was performed with monoethanol-
amine and diethanolamine to synthesize bis(octadecyloxy)-
2- hydroxypropylmonoethanolamine (D-MEA)and octade-
cyloxy-2-hydroxypropyldiethanolamine(M-DEA) without
catalyst at 60 °C, respectively. And their corresponding
tertiary amine salts bis(octadecyloxy)-2-hydroxypropylmo-
noethanolamine hydrochloride (D-MEAS) and octadecyl-
oxy-2-hydroxypropyldiethanolamine hydrochloride (M-
DEAS) were attained by neutralization with hydrochloric
acid. The study on these four surfactants included their surface
active properties, foaming abilities, emulsifying properties,
lime-soap dispersion abilities and wetting abilities. The results
show that D-MEAS possesses the best surface active property
and lime-soap dispersion ability. D-MEA has better foaming
ability and foaming stability. The wetting ability of M-DEA
and the emulsifying property of M-DEAS are prominent.
contain two hydrophilic groups and one or more long-chain
alkyl groups. The alcohol amine derivatives like alkan-
olamide are a kind of important non-ionic surfactant. An
alkanolamide surfactant was first investigated by AM
Schwartz and JW Perry in the 1940s and it was developed
in the 1990s. It has become one of the developmental
directions of surfactants [1, 2]. Most often, alkanolamides
are prepared by reactions of diethanolamine with long-
chain fatty acids or fatty acid esters. Not only the amino but
also the hydroxyl of diethanolamine can react with the
long-chain fatty acid. So the purity and quality of the final
product made by the reaction of diethanolamine with a
fatty acid are not very good, and the reaction of dietha-
nolamine with a fatty acid ester is complex and takes place
under harsh conditions [3–5].
Another kind of alcohol amine derivative is ester quats
which possess excellent performance and biodegradability
and have become a new generation of fabric-softening
agents [6, 7]. In general, the ester quats are prepared by
esterification of triethanolamine with fatty acid [8, 9],
followed by the reaction with an alkylating agent to result
in the corresponding quaternary ammonium salt [10, 11].
The products of the esterification reaction are a mixture of
mono-, di- and tri-esteramine, and the ultimate perfor-
mance of ester quats is affected by the content of the blend.
Most of the synthetic reactions of alkanolamides and ester
quats are carried out under higher temperature and the
products contain many by-products.
Keywords Amphiphiles ꢀ Monoalkyl diethanolamine ꢀ
Dialkyl monoethanolamine ꢀ Surfactant
Introduction
Amphipathic compounds derived from short-chain alcohol
amines, such as monoethanolamine, diethanolamine and
triethanolamine, are a new type of surfactants, which may
In this paper, two types of N-substituted long-chain
alkanolamine surfactants, which had a similar structure to
alkanolamides and ester quats, were prepared by the ring-
opening reaction of octadecyl glycidyl ether with mono-
ethanolamine and diethanolamine at 60 °C. As far as we
know, this synthetic route is simpler and has not been
reported previously. Active ingredients, surface active
Y. Zhang (&) ꢀ Y. Xu ꢀ S. Qiu ꢀ L. Yang
School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China
e-mail: xiao.ya.zi@163.com
123

J Surfact Deterg
Synthesis of Octadecyl Glycidyl Ether
properties and application properties of the products were
evaluated. In addition, the products were characterized by
Fourier transform infrared spectroscopy (FTIR).
A solution of octadecanol and BF3ꢀOEt2 in cyclohexane
was heated to 60 °C. Epichlorohydrin was added dropwise
at a rate which was sufficient to maintain the reaction
temperature at 58–62 °C. The resulted mixture was then
aged at 60 °C for 90 min. The reactants were then cooled
to 40 °C and aqueous NaOH was added dropwise within
1 h, to maintain the reaction temperature below 40 °C for
4 h until the completion of cyclization. Water and cyclo-
hexane were added afterward and the contents were sepa-
rated into two layers. The resulting organic layer was
washed with water several times until the pH reached 7 and
then distilled to remove the solvent. The final crude mass
was further purified by recrystallization from ether. The
final yield of octadecyl glycidyl ether was 81.2 %.
Materials and Methods
Materials
Chemicals and solvents were epichlorohydrin (C99.5 %),
octadecanol (C99 %), BF3ꢀOEt2 (47 % BF3, 53 % Et2O),
sodium hydroxide (C96 %), monoethanolamine (C99 %),
diethanolamine (C99 %), cyclohexane (C99.5 %), anhy-
drous ethanol (C99.7 %) and anhydrous diethyl ether
(C99 %), hydrochloric acid (37–38 % HCl). All of the
chemicals used in this study were of analytical grade and
purchased from Tianjin GF Fine Chemicals in China.
Synthesis of M-DEA and M-DEAS
Synthetic Procedure of Surfactants
The reaction was carried out in a reaction flask submerged
in a water bath. Diethanolamine was added to the reaction
flask equipped with a mechanical stirrer, thermometer and
condenser. Octadecyl glycidyl ether was then added
dropwise into the reaction flask at a molar ratio of 1:0.8
(diethanolamine to octadecyl glycidyl ether) in the pres-
ence of anhydrous ethanol as solvent. The reaction was
carried out at 60 °C for 4 h. Then the reaction mixture was
cooled to room temperature and then distilled to remove
the solvent. The residue was washed with saturated NaCl
aqueous solution several times and centrifuged at
6,000 rpm for 10 min. The resulting crude mass was
Firstly, octadecyl glycidyl ether was synthesized from octa-
decanol and epichlorohydrin. Then octadecyloxy-2-hydro-
xypropyldiethanolamine (M-DEA) and bis(octadecyloxy)-2-
hydroxypropylmonoethanolamine (D-MEA) were prepared
by the reaction ofoctadecyl glycidyl ether with diethanolamine
and monoethanolamine, respectively. Their corresponding
salts, i.e., octadecyloxy -2-hydroxypropyldiethanolamine
hydrochloride (M-DEAS), bis(octadecyloxy)-2- hydro-
xypropylmonoethanolamine hydrochloride (D-MEAS) were
obtained by neutralization with hydrochloric acid. The scheme
for the reaction is shown in Fig. 1.
Fig. 1 Reaction scheme for the
synthesis of alkanolamine
surfactants
BF3·OEt2
NaOH
CH
O
H2C
Cl
CH2
+
C18H37OH
C18H37O H2C CH2 CH2
OH Cl
1-Chloro-3-octadecyloxy-propan-2-ol
Octadecanol
Epichlorohydrin
°
60
NH C2H5OH
C18H37 O CH2
CH CH2
OH
N C2H5OH 2
2
C18H37
CH2 CH
O
CH2
M-DEA
Diethanolamine
O
°
60
Octadecyl glycidyl ether
C18H37
O CH2
CH2
CH
OH
NC2H5OH
NH2C2H5OH
2
Monoethanolamine
D-MEA
HCl
C18H37
CH2 N H C2H5OH 2Cl
O
CH2 CH
OH
M-DEAS
HCl
O CH2
C18H37
CH
CH2 N HC2H5OHCl
2
HO
D-MEAS
123

J Surfact Deterg
further purified by recrystallization from ether, followed by
drying in a vacuum at 30 °C overnight. The final yield of
the M-DEA was 87.3 %. Afterward, M-DEA was dissolved
in a mixture of ethanol and ether. To the resulting solution
hydrochloric acid was added slowly and then the solution
was filtered and dried under vacuum to get the pure
M-DEAS.
(0.1 0.01 wt%) of the surfactants were prepared. Then
four 100-mL stoppered graduated measuring cylinders were
charged 40 mL of an aqueous solution of surfactants,
respectively. Then every cylinder was separately poured
through the side of its wall into 40 mL of cyclohexane,
kerosene, soybean oil and liquid paraffin. The cylinders were
turned upside down a total of five times at a rate of five turns
per 1 min. Then the cylinders were left to stand. The time
required to separate 10 mL of aqueous phase in every cyl-
inder was recorded. The experiment was repeated five times
and the average time was defined as emulsifying character-
istic persistence time. Equilibrium emulsifying time data
were reproducible within 2 s. The shorter the time was, the
poorer was the emulsifying ability [14].
Synthesis of D-MEA and D-MEAS
The synthesis procedures of D-MEA and D-MEAS were
similar to those of M-DEA and M-DEAS, except that the
molar ratio of monoethanolamine to octadecyl glycidyl
ether was 1:1.8. The final yield of the D-MEA was 95.6 %.
Dispersing Capability
Evaluation of Surfactant Properties
Surface Tension
First aqueous solution (0.25 0.01 wt%) of the surfactants
were prepared. Secondly 5 mL of aqueous solution
(0.5 0.01 wt%) of sodium stearate and 10 mL of ‘‘hard
water’’ (containing 665 mg/L CaCl2 and 986 mg/L
MgSO4ꢀ7H2O) were mixed in a 100-mL stoppered gradu-
ated measuring cylinder. Then a certain amounts of the
aqueous solution (0.25 0.01 wt%) of surfactants were
added to the cylinder. The cylinder was turned upside down
for a total of 20 times at a rate of 1 turn per 30 s. Increasing
the dosage of aqueous solution of surfactants gradually
until the coagulation in the cylinder had disappeared and
the measuring cylinder mixture was translucent. At that
time the added amount of surfactant solution was recorded,
and this was repeated three times and average value was
defined as V1. The accuracy of the volume was 0.1 mL and
equilibrium LSDR were reproducible within 1 % [15].
The surface tension of different concentrations of surfac-
tants aqueous solution (0.03–0.0003 0.00002 mol L-1
)
was determined by the drop volume method [12]. It was
measured using a Lauda TVT 2E drop volume tensiometer
(resolution 0.01 mN m-1) at 20 °C with a controlled
temperature bath system. The average value of three
measurements of the surface tension data was used. Equi-
librium surface tension data were reproducible within
0.1 mN m-1
.
Foaming Ability
Foaming ability was measured according to the Ross–Miles
method [13]. It was measured using MBM-RI Ross–Miles
apparatus (accuracy 0.1 mL) at 25 and 50 °C with a
temperature-controlled bath system. First aqueous solu-
tions (0.25 0.01 wt%) of the surfactants were prepared.
Then 500 mL of one of the aqueous solutions was poured
into a 1,000-mL graduated cylinder from a height of
450 mm. The foam volume of the aqueous solution was
measured at 30 s, 3 min and 5 min separately after the
pouring, respectively, each of which was repeated three
times and the average value was used for estimating the
foam ability and foam stability of the surfactants. Equi-
librium foam volume data were reproducible within
0.6 mL.
LimeꢁSoap Dispersion Requirement ðLSDRÞ=%
V1 ꢂ 0:25% ꢂ 100
¼
ð1Þ
V2 ꢂ 0:5%
where V1 is the amount of surfactant solution (mL) and V2
is the amount of sodium stearate solution (5 mL).
Wetting Ability
The wetting ability of the different concentrations of sur-
factants solution (0.01–2.5 0.001 g/L) in distilled water
onto canvas were determined using the canvas disc method
[16]. The time for a canvas wafer from immersion to
starting to sink in the surfactant solution was measured, this
was repeated ten times and the average time was defined as
the wetting time. The accuracy of the time was 0.1 s and
equilibrium wetting time data were reproducible within 1 s.
Then the curve of wetting time vs surfactants concentration
was drawn.
Emulsifying Ability
The emulsifying abilities of the aqueous solutions of sur-
factants were determined in the systems of cyclohexane/
water, kerosene/water, soybean oil/water and liquid paraffin/
water at room temperature (25 °C). First aqueous solutions
123

J Surfact Deterg
Fourier Transform Infrared Spectroscopy
Table 1 Amine value and active ingredients of surfactants 25 °C
Sample
Tested amine
value/mg KOH g-1
Theory amine
value/mg KOH g-1
Active
ingredients/ %
The FTIR spectra of the octadecyl glycidyl ether, D-MEA
and M-DEA were recorded using a Bio-Rad FTS-6000
spectrometer. The samples were spread over KBr cuts
and their spectra were recorded in the range of
M-DEA
D-MEA
110.08 0.50
76.15 0.30
112.82
78.62
98.21 0.44
96.86 0.38
4,000–400 cm-1
.
The surface tension values of M-DEA, M-DEAS,
D-MEA and D-MEAS at different concentrations of
aqueous solution at 20 °C are shown in Table 2. Figure 3
shows the surface tension versus the logarithm of surfactant
concentration of M-DEA, M-DEAS, D-MEA and D-MEAS
at 20 °C. As expected, the surface tension of the surfactant
solution reduces dramatically with the increase in con-
centration. When the surfactant concentration increases to
the critical micelle concentration (CMC) value, the micelle
begins to form and the surface tension tends to be constant.
The CMC values are the concentration at the intersection of
two linear parts of the relationship in the plot above and
below the discontinuity. The maximum surface excess
concentration of the surfactant solutions are calculated
from the Gibb’s adsorption equation (Eq. 2) [18].
Results and Discussion
Figure 2 shows the FTIR results of the octadecyl glycidyl
ether, D-MEA and M-DEA. The peaks at 2,971, 2,850,
1,468, 722 and 1,125 cm-1 appear in all the spectra. The
peaks at 2,971, 2,850 cm-1 are attributed to the –CH3
and –CH2 stretching frequency. The values of 1,468 and
1,125 cm-1 are attributed to –CH2 bending frequency and
C–O stretching frequency, respectively. The characteristic
peak at 722 cm-1 is attributed to saturated alkyl of the long
chain. The band at 3,383 cm-1, appearing in the spectra of
M-DEA and D-MEA, is attributed to the frequency of
vibration of –OH group of M-DEA and D-MEA. The peaks
at 909 and 843 cm-1 from the octadecyl glycidyl ether
referred to the frequency of deformation of epoxy group
confirm the formation of epoxide, and they are not found in
the spectra of M-DEA and D-MEA, indicating the success
of epoxidation. Also the peaks at 880, 1,643 cm-1 referred
to the frequency of vibration of C–N are only found in the
spectra of M-DEA and D-MEA.
Cmax ¼ ðdc=d log CÞ = ð2:303RTÞ
ð2Þ
And the minimum surface area at the air–water interface
occupied by each surfactant molecule at the saturation
condition is calculated using Eq. (3) [18].
Amin ¼ 1016=NCmax
ð3Þ
Amine value means that amine alkalinity in 1 g of the
sample is equivalent to amounts of mg KOH. It is deter-
mined by non-aqueous titration of perchloric acid [17]. The
amine value and active ingredients of M-DEA and D-MEA
surfactants are presented in Table 1. Equilibrium amine
In the above Eqs. (2) and (3), c is the equilibrium
surface tension (mN m-1),
C
is the surfactant
concentration (mol L-1), dc/dlogC is the slope of the
surface tension profile at the pre-CMC region, R is the
universal gas constant (R = 8.314 J mol-1 K-1), T is
the absolute temperature and N is Avogadro’s number
(6.023 9 1023).
value is reproducible within 0.5 mg KOH g-1
.
1.2
The results obtained are summarized in Table 3, which
also includes the following adsorption parameters: cCMC
(the effectiveness of surface tension reduction) and pC20
(the efficiency of surface adsorption as the negative loga-
rithm of the bulk surfactant concentration C20 required to
reduce the surface tension of water by 20 mN m-1). We
can conclude from the cCMC and pC20 values that D-MEAS
has stronger effectiveness of surface tension reduction and
better efficiency of surface adsorption than D-MEA,
M-DEAS and M-DEA.
octadecyl glycidyl ether
1.0
D-MEA
0.8
0.6
0.4
0.2
M-DEA
The thermodynamic behaviors of the synthesized sur-
factants in their solutions were studied using the standard
free energies of adsorption and micellization. The standard
free energies of adsorption (DGa0ds) and micellization
(DG0CMC) of the surfactants at the air/water interface or in
the bulk of the solution are evaluated using Eqs. (4, 5) [18].
4000
3500
3000
2500
2000
1500
1000
500
Wave number/cm-1
Fig. 2 FTIR spectrum of octadecyl glycidyl ether, D-MEA and
M-DEA
123

J Surfact Deterg
Table 2 Surface tension of different concentrations of surfactants solution at 20 °C
Concentration/
mol L-1
Surface tension/mN m-1
0.03 0.025
0.015
0.01
0.006
0.004
0.003
0.0015
0.0003
M-DEA
M-DEAS
D-MEA
D-MEAS
36.7 0.1 36.7 0.1 36.8 0.1 36.9 0.2 38.9 0.3 40.2 0.3 42.6 0.4 51.3 0.3 60.2 0.3
36.2 0.1 36.3 0.1 36.4 0.1 36.3 0.2 38.6 0.3 39.8 0.2 41.7 0.3 48.6 0.4 56.5 0.2
35.8 0.1 35.8 0.1 35.8 0.2 35.8 0.2 36.1 0.3 38.7 0.4 40.9 0.3 47.7 0.4 54.4 0.2
34.6 0.2 34.6 0.1 34.8 0.2 34.8 0.2 34.9 0.1 35.0 0.1 35.0 0.1 42.2 0.3 50.3 0.4
with two lipophilic chains are much smaller than those of
M-DEA and M-DEAS with one lipophilic chain. This is
42
40
38
M-DEA
M-DEAS
D-MEA
D-MEAS
because the structures of D-MEA and D-MEAS with two
lipophilic chains and an amine group and two hydroxyl
groups are similar to gemini surfactants, which have
excellent micellization and surface active property [19]. To
compare with the other similar surfactants reported, the
CMC value of the octadecyl quaternary ammonium salt
surfactant is 9.55 9 103 and its cCMC is 50.9 mN m-1 as
reported by Xuqun [20], while CMC value of D-MEA is
2.8 9 103 and cCMC of D-MEA is 35 mN m-1. So the
D-MEAS possesses the better surface activity.
γ
36
34
The gas is dispersed in the liquid to form the foam
which is a thermodynamically unstable system. Surfactants
can reduce the interfacial tension between the gas and
liquid to form a stabilized foam. Tables 4, 5 show the
results of foam volume tests at 25 and 50 °C. Significant
improvement in foam volume is observed with the increase
in the temperature, probably because of the decrease in
surface tension and interfacial viscosity. In addition, better
solubility of lipophilic chains at higher temperatures makes
the strength and elasticity of the interfacial film improve
simultaneously, resulting in the enhancement of the
foaming power. Foaming power and foaming stability of
D-MEA were found to be better than those of the other
surfactants caused by the two lipophilic chains within
D-MEA at a certain temperature. When the two lipophilic
chains are arranged in the gas–liquid interface, intermo-
lecular forces become larger, leading to the enhancement
of mechanical strength of interfacial film and the
improvement of viscosity of surface membrane. The
foaming power of the alkanolamide polyglycerol ether
reported by Wangying is 60/55 (0 s/5 min) at 40 °C [21],
while that of D-MEA is 59.7/50 (30 s/5 min) at 25 °C and
-3.0
-2.5
-2.0
-1
-1.5
logC/mol · L
Fig. 3 Plots of surface tension at 20 °C vs logarithm of concentration
of surfactant
DG0ads ¼ ꢁ2:303RTpC20
DG0CMC ¼ 2:303RT log CMC
As shown in Table 3, the standard free energies of
adsorption and micellization of the synthesized surfactants
are always negative. This indicates that both adsorption and
micellization processes occur spontaneously. Moreover,
ð4Þ
ð5Þ
0
0
D
D
the GCMC and Gads of D-MEAS are more negative than
those of D-MEA, M-DEAS and M-DEA, which reveals
that the adsorption process and micellization of D-MEAS
are more favorable. Umax and Amin values indicate that the
D-MEAS also possesses a larger maximum surface excess
concentration and higher compactness at the interface. The
order of CMC values of these four surfactants are as
follows: D-MEAS \ D-MEA \ M-DEAS \ M-DEA. It
indicates that the CMC values of D-MEA and D-MEAS
Table 3 Surface and thermodynamic properties of the synthesized surfactants at 20 °C
2
CMC value/mol L-1
c
CMC/mN m-1
pC20/mol L-1
U
max/mol cm-2
DG0ads/KJ mol-1
DG0CMC/KJ mol-1
˚
Amin/A
Compound
M-DEA
M-DEAS
D-MEA
D-MEAS
1 9 10-2
36.9
36.4
35.8
35.0
3.30
3.56
3.25
3.62
2.20 9 10-10
1.86 9 10-10
2.98 9 10-10
2.56 9 10-10
75.43
89.22
55.69
64.82
-18.54
-19.95
-18.23
-20.28
-11.22
-11.79
-12.86
-14.32
7.9 9 10-3
5.1 9 10-3
2.8 9 10-3
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J Surfact Deterg
A surfactant possesses the ability to disperse the
agglomerative solid particle, and this is called dispersibil-
ity. Generally, dispersibility is measured by its lime-soap
dispersion ability. Table 7 shows the results of lime-soap
dispersion abilities of M-DEA, M-DEAS, D-MEA and
D-MEAS. As shown, D-MEAS has a better lime-soap
dispersion ability than those of the others. The reason is
that D-MEAS adsorbed onto the particle surface involves
two lipophilic chains and forms a large steric hindrance.
Meanwhile hydrophilic group has a strong hydration ability
in water to form a hydrated layer due to its good water
solubility. While the relatively poor water-solubility of
D-MEA leads to poor lime-soap dispersion ability. The
lime-soap dispersion ability (LSDR %) of the alkanolamide
polyglycerol ether reported by Wangying is 26 % [21],
while that of D-MEAS is 15 %. As defined above, the
smaller the LSDR %, the better is the dispersibility. Con-
sequently, the lime-soap dispersion ability of D-MEAS is
much better than that of the alkanolamide polyglycerol
ether. M-DEAS and M-DEA are similar with the alkan-
olamide polyglycerol ether, whereas D-MEA is much
poorer.
Table 4 Variation of foam volume with time for surfactants at 25 °C
Sample
Foam volume/mL
30 s
3 min
5 min
M-DEA
M-DEAS
D-MEA
D-MEAS
61.5 0.5
38.6 0.6
59.7 0.5
43.0 0.5
20.3 0.4
27.3 0.5
50.0 0.4
34.0 0.3
10.1 0.5
27.3 0.3
50.0 0.4
34.0 0.2
Table 5 Variation of foam volume with time for surfactants at 50 °C
Sample
Foaming volume/mL
30 s 3 min
95.4 0.6
5 min
M-DEA
M-DEAS
D-MEA
D-MEAS
45.0 0.5
50.0 0.4
168.0 0.4
45.0 0.5
38.3 0.5
50.0 0.4
168.0 0.3
45.0 0.2
56.8 0.5
184.0 0.5
50.0 0.4
184/168 (30 s/5 min) at 50 °C. We can infer that the
foaming power D-MEA is better than that of the alkan-
olamide polyglycerol ether prepared.
A surfactant can adsorb at the solid–liquid and liquid–
gas interface when it is added to the solution. The
adsorption leads to the solid surface wetting due to the
hydration of surfactant. The more surfactant adsorbs onto
the solid surface, the stronger the wetting ability is. An
aqueous solution of a surfactant can wet a solid surface due
to the adsorption and hydration of the surfactant. The
wetting ability mainly depends on the interaction between
the solid surface and the surfactants. The wetting times
versus surfactant concentration for M-DEA, M-DEAS,
D-MEA and D-MEAS are shown in Fig. 4. As shown here,
the wetting abilities of these four surfactants follows the
order: M-DEA [ D-MEA [ D-MEAS [ M-DEAS. This
kind of interaction between the solid surface and the non-
ionic surfactants such as M-DEA and D-MEA is stronger
than that of cationic surfactants such as D-MEAS and
M-DEAS, so the wetting ability of M-DEA and D-MEA is
better than that of D-MEAS and M-DEAS. Generally
speaking, nonionic surfactants with a stronger hydrophilic
character have better wetting ability, so the wetting ability
of M-DEA is the best among the others. The wetting time
The emulsifier can decrease the rate of coalescence of
the emulsified droplets by adsorbing onto the surface of the
droplets and forming steric hindrance and electrical barri-
ers. Table 6 shows the results of the emulsifying abilities of
the surfactants in the systems of cyclohexane/water, kero-
sene/water, soybean oil/water and liquid paraffin/water. As
shown here, the emulsifying ability of M-DEAS is the best
among the four surfactants and the relatively segregation
time for M-DEAS is more than 700 s. The emulsion sta-
bility depends on the strength and stability of the interfacial
film [22]. M-DEAS dissolves well in both oil and in water.
The hydrophobic group can be arranged closely to the oil–
water interface, thus increasing the molecular density of
interface adsorption and enhancing molecular interaction.
So the interfacial film becomes stronger and the emulsion
becomes more stable. The relatively separation time of the
alkanolamide reported by Adewale Adewuyi is 45 s [3]. In
comparison with that, the M-DEAS has an excellent
emulsifying ability and can participate in emulsion poly-
merization as the emulsifier.
Table 6 Emulsifying property of surfactants at Cyclohexane/water, Kerosene/water, Soybean Oil/water, Liquid Paraffin/water systems at 25 °C
Sample
Relatively stratification time/s
Cyclohexane/water
Kerosene/water
Soybean oil/water
Paraffin/water
M-DEA
M-DEAS
D-MEA
D-MEAS
368.1 1.6
1,849.0 1.4
324.2 1.1
66.8 0.5
343.2 1.8
1,530.4 1.6
370.8 1.7
88.0 0.5
359.0 1.3
1,296.1 1.5
86.3 0.6
122.0 1.2
730.4 1.3
71.6 0.5
49.0 0.4
120.0 0.8
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2. Kang Y, Cai XJ (2012) Research development of alkanolamide
surfactant. Adv Fine Petrochemicals 40:49–61
Table 7 Lime-soap dispersion ability of surfactants 25 °C
Sample
M-DEA
M-DEAS
D-MEA
D-MEAS
3. Adewuyi A, Oderinde RA, Rao BVSK, Prasad RBN (2012)
Synthesis of alkanolamide: a nonionic surfactant from the oil of
Gliricidia sepium. J Surfact Deterg 15:89–96
LSDR/%
25.2 0.4
22.0 0.2
60.4 0.5
15.0 0.2
4. Liu NN, Xia YM, Gu ZM (2012) Synthesis and properties of
palmitoyl ethanolamide and palmitoyl diethanolamide. Fine
Chemicals 29:6–9
5. Kolancilar H (2004) Preparation of laurel oil alkanolamide from
laurel oil. J Am Oil Chem Soc 81:597–598
1000
100
10
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ionic fabric Softeners. J Oleo Sci 56:269–276
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triethanolamine over zirconium sulfate supported on SBA-15
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of polyethoxy ester quaternary ammonium salts. China Surf
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M-DEA
M-DEAS
D-MEA
D-MEAS
0.01
0.1
1
-1
10
concentration/g · L
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gemini surfactants with dodecyl side chains and different spacers,
including partially fluorinated spacers, on different surfaces:
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properties of 4,40-di(n-tetradactyl) diphenylmethane disulfate
salt. Appl Chem Ind 41:317–320
Fig. 4 Plots of wetting time vs concentration of surfactants
of M-DEA is 2.1 s when the concentration of the aqueous
solution is 2.5 g/L. Compared with the alkanolamide
reported by Adewale Adewuyi where the wetting time is
33 s [3], we can comes to the conclusion that M-DEA has a
better wetting property.
Conclusion
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face active properties of amphipathic compounds with two sulfate
groups and two lipophilic alkyl chains. J Am Oil Chem Soc
67:459–463
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New York
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Oil Chem Soc 6:363–366
18. Rosen MJ (2001) Surface and interfacial phenomena, 2nd edn.
Wiley, NY
In this paper four surfactants of M-DEA, M-DEAS,
D-MEA and D-MEAS were synthesized without a catalyst
at 60 °C from octadecyl glycidyl ether, monoethanolamine
and diethanolamine. The surface active properties, foam-
ing, emulsifying, lime-soap dispersing and wetting abilities
of the four surfactants were investigated. Surface active
parameters relating to the effectiveness and efficiency of
surface tension reduction, standard free energies of
adsorption and micellization, and CMC values were
determined from surface tension data. Among the four
surfactants, it was shown that D-MEAS possesses an
excellent surface active property and lime-soap dispersing
ability. D-MEA has better foaming ability and foaming
stability. The wetting ability of M-DEA and emulsifying
property of M-DEAS are of note.
19. Tehrani-Bagha AR, Holmberg K (2010) Cationic ester-containing
gemini surfactants: physical-chemical properties. Langmuir
26(12):9276–9282
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properties of dissymmetric gemini quaternary ammonium salts
cationic surfactants. China Surf Deterg Cosm 34:280–282
21. Wang Y, Xia LS, Xia YT (2012) Synthesis and properties of
alkanolamide polyglycerol ethers. Chem Eng 40:49–61
22. Terri A, Camesano RN (2000) Micelle formation and CMC of
gemini surfactants: a thermodynamic model. Colloids Surf A
167:165–177
Author Biographies
References
Ya Zhang Is currently a master’s student in chemical engineering at
Tianjin University, China, and is working on a thesis on the
preparation of the surfactants and the materials of fine chemical
intermediates.
1. Schwartz AM, Perry JW (1949) Surface active agents: their
chemistry and technology, vol I. Interscience Publishers, New
York
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Yongshen Xu is currently a professor of chemical engineering and a
doctoral tutor at Tianjin University, China, with a research emphasis
in the area of surfactants and miniemulsion polymerization.
Lei Yang is currently a master’s student in chemical engineering at
Tianjin University, China, with a research emphasis on the prepara-
tion of PDMS/SiO2 nanocomposites.
Shouji Qiu is currently a master’s student in chemical engineering at
Tianjin University, China, with a research emphasis on the prepara-
tion of PDMS-ormosil and its application in mini emulsion
polymerization.
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