Synthesis and Performance Evaluation of CO2/N2 Switchable Tertiary Amine Gemini Surfactant

Article abstract of DOI:10.1007/s11743-017-2019-8

A type of switchable tertiary amine Gemini surfactant, N,N′-di(N,N-dimethyl propylamine)-N,N′-didodecyl ethylenediamine, was synthesized by two substitution reactions with 3-chloro-1-(N,N-dimethyl) propylamine, bromododecane and ethylene diamine as main raw materials. The structure of the product was characterized by FTIR and ¹H-NMR. We also investigated the surface tension when CO₂ was bubbled in different concentrations of surfactant solution and the influence of different CO₂ volumes on surface tension under a constant surfactant concentration. Finally the surface tension curve and the related parameters were acquired by surface tension measurements. The experimental results showed that the structure of the synthesized compounds were in conformity with the expected structure of the surfactant, and displayed a better surface activity after bubbling CO₂. The critical micelle concentration (CMC) surface tension at CMC (γ_cmc) pC₂₀ (negative logarithm of the surfactant’s molar concentration C₂₀, required to reduce the surface tension by 20?mN/m) surface excess (Γ_max) at air/solution interface and the minimum area per surfactant molecule at the air/solution interface (A_min) were determined. Results indicate that the target product had good surface activity after bubbling CO₂.

Full text of DOI:10.1007/s11743-017-2019-8

J Surfact Deterg (2017) 20:1483–1489
DOI 10.1007/s11743-017-2019-8
SHORT COMMUNICATION
Synthesis and Performance Evaluation of CO /N Switchable
2
2
Tertiary Amine Gemini Surfactant
1
,2
1
1,2
1,2
1,2
•
Ming Zhou
1
Buhua Hu
•
Gang Wang
Yunlong Zhao
•
Yaoyang Xu
•
Ze Zhang
•
Sisi Li
,2
1,2
•
Received: 18 January 2017 / Accepted: 27 August 2017 / Published online: 20 September 2017
Ó AOCS 2017
Abstract A type of switchable tertiary amine Gemini sur-
The experimental results showed that the structure of the
synthesized compounds were in conformity with the
expected structure of the surfactant, and displayed a better
0
0
factant, N,N -di(N,N-dimethyl propylamine)-N,N -didode-
cyl ethylenediamine, was synthesized by two substitution
reactions with 3-chloro-1-(N,N-dimethyl) propylamine,
bromododecane and ethylene diamine as main raw materi-
als. The structure of the product was characterized by FTIR
surface activity after bubbling CO . The critical micelle
2
concentration (CMC) surface tension at CMC (ccmc) pC20
(negative logarithm of the surfactant’s molar concentration
C , required to reduce the surface tension by 20 mN/m)
1
and H-NMR. We also investigated the surface tension
2
0
when CO was bubbled in different concentrations of sur-
2
surface excess (Cmax) at air/solution interface and the
minimum area per surfactant molecule at the air/solution
interface (Amin) were determined. Results indicate that the
target product had good surface activity after bubbling CO2.
factant solution and the influence of different CO volumes
2
on surface tension under a constant surfactant concentra-
tion. Finally the surface tension curve and the related
parameters were acquired by surface tension measurements.
Keywords CO /N switchable surfactant Á Tertiary
2
2
amine Á Performance evaluation
&
Ming Zhou
drzhouming@sohu.com; mr.zhouming@163.com
Introduction
Gang Wang
w1028369813@163.com
Traditional surfactants do not react chemically in use, but
they are difficult to separate from the used solution, caus-
ing wasted product and potential for environmental dam-
age. In recent years, with the development of green
chemistry, traditional surfactants are being replaced by
more environmentally friendly surfactants. Switchable
surfactants can be reversibly changed between non-sur-
factant and surfactant behaviors in response to an external
trigger such as pH [1, 2], temperature [1, 3], light [4], or a
Yaoyang Xu
1
003266528@qq.com
Ze Zhang
zhangzesuse@sina.com
Sisi Li
li742295979@qq.com
Buhua Hu
1
570821955@qq.com
Yunlong Zhao
84112515@qq.com
redox reagent [5]. CO /N switchable surfactants can
2
2
5
transform between non-surfactant and surfactant by con-
trolling the addition and removal of CO . It is easy to
2
1
2
School of Materials Science and Engineering, Southwest
Petroleum University, Chengdu, 610500, China
separate the surfactant after CO has been injected into the
2
used solution. Research nto CO switchable surfactants is
2
State Key Laboratory of Oil and Gas Reservoir Geology and
Exploitation, School of Materials Science and Engineering,
Southwest Petroleum University, Chengdu 610500, Sichuan,
China
becoming more and more popular because CO is a cheap
2
and widely available raw material.
1
23

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484
J Surfact Deterg (2017) 20:1483–1489
the reverse sol-to-gel transition. In 2012, Jessop et al.
H O
2
N
N
+
CO2
HCO -
reported a kind of switchable solvent N,N-dimethyl
+
3
N
N
cyclohexylamine (CyMe ) [13] for oil-sand separation, and
2
H
a kind of tertiary amine N,N-dimethyl ethanolamine
(DMEA) [14], which could self-assemble with a traditional
2 2
Scheme 1 The reaction of DBU with CO and H O
surfactant to form a switchable surfactant.
The studies of tertiary amine structure of polymers or
micromolecules in the literature provides an idea for
In 1978, Iwatani et al. [6] reported that a white solid
could be obtained by DBU (1,8-diazabicyclo [5.4.0] undec-
exploring tertiary amine CO switchable surfactant.
2
7
-ene) reacting with CO , but did not identify the chemical
2
In this paper, we introduce a kind of CO /N switchable
2
nature of the solid. In 2005, Jessop and co-workers [7]
proved that a bicarbonate cationic complex could be
obtained by the equimolar reaction of DBU, water and
CO . The reaction is shown in Scheme 1. After the CO
2
Gemini surfactant, and we describe the use of carbon
dioxide (CO ) as an efficient trigger to control either non-
2
surfactant or surfactant transitions.
2
2
was removed, the bicarbonate decomposed into the initial
state. The same team [8] also applied the technique to the
emulsification and demulsification process of both light
crude oil and heavy oil. In 2009, Qinet et al. [9] reported
that dodecyl tetramethyl guanidine could form a bicar-
Experimental
Materials
bonate ionic adduct after being exposed to CO . It could be
2
Ethylenediamine, ethanol, bromododecane and potassium
iodide were purchased from Kelong Ltd., Chengdu, China.
used as a CO switchable surfactant; the principle is shown
2
in Scheme 2. In 2014, Lu et al. [10] investigated the
foaming performance of 2-alkyl-1-hydroxyethylimida-
zolinium bicarbonate cationic surfactants (HEAIBs) for the
first time. They found that the surface activity of the sur-
factants was reversibly switchable; it could be shifted
between ionic and neutral states by alternatively bubbling
CO and N . There are two types of CO switchable sur-
All chemical reagents were analytical grade. CO (g) and
2
N were purchased from Jingli Gas Company, Chengdu,
2
China. 3-Chloro-1-(N,N-dimethyl) propylamine was pre-
pared in our laboratory. Distilled water was prepared in our
laboratory by a model 1810-B quartz automatic dual dis-
tilled water apparatus.
2
2
2
factant, amidine base and guanidine base. Because of the
high cost of amidine base switchable surfactant, its industry
synthesis is limited. Because the bicarbonate of guanidine
base switchable surfactant needs a higher decomposition
temperature, its reversible process is very difficult, so it is
rarely applied in industry.
Methods
1
H-nuclear magnetic resonance (NMR) spectra were
recorded on a Bruker (Bruker Corporation, Germany)
AVANCE III 400 spectrometer (400 MHz) with D-DMSO
solvent. Infrared (IR) spectra were obtained on a Nicolet
From 2010, the researchers at home and abroad trans-
ferred their focus from amidine base and guanidine base
switchable surfactants to a more moderate, reversible,
efficient tertiary amine structure. In 2012, Zhao Yue [11]
discovered that poly(N,N-dimethylaminoethyl methacry-
late) (PDMAEMA) in water could react with carbon
6700 spectrometer (Nicolet Corporation, USA). Surface
tension was determined by using a JK99B automatic ten-
siometer at 20 °C in the Du N o¨ uyring method. Conduc-
tivity was obtained by using a DDS-11A conductivity
meter (Sile Instrument Reagent Company, Shanghai,
China). An OWC-9360 constant speed blender (Shenyang
Institute of Aeronautical Engineering) was also used.
dioxide (CO ), such that the system’s lower critical solu-
2
tion temperature (LCST) could be reversibly tuned by
passing CO and argon (Ar) through the solution. In the
2
Synthesis
same year, Han Dehui [12] reported CO -responsive ABA
2
triblock copolymer hydrogels (the structure is shown in
Scheme 3). Through rational block copolymer design, the
Ethylenediamine (0.045 mol) and ethanol (20 mL) were
mixed and then added to a 250 mL three-necked flask at
hydrogels could undergo either CO -induced gel-to-sol or
2
70 °C. 1-bromododecane (0.1 mol) was dissolved in the
ethanol solution, then was added slowly into the three-necked
flask by constant pressure funnel, and the raw materials were
constantly stirred for about 24 h (Scheme 4). Finally, the
mixture was filtered while hot and the solid product was
washed with ethanol three times. The solid product was dried
NHMe2
NMe2
CO ,H O
2
2
H
R
N CH
R N
C
HCO3
0
Scheme 2 The ‘‘on’’ and ‘‘off’’ of guanidine switchable surfactants
at 50 °C for 24 h; the yield of N,N -didodecyl
1
23

J Surfact Deterg (2017) 20:1483–1489
1485
Scheme 3 The structure of
CO -responsive ABA triblock
2
CH3
CH3 CH O
O CH3 CH3
CO CH CH O C C CH2 C 180CH2 C 38
CH3
3
copolymer hydrogels
CH2
C
CH2 C 38
C
2
2
180
455
CH3
C O
O
C O
O
C O CH3
O
C O
O
CH2
CH2
CH2
CH2
CH2
CH2
N
CH2
O
CH2
O
N
H C
CH3
H C
CH3
3
3
HN (CH2)11CH3
C N(CH ) ), and 2.341–2.765 ppm (t, 16H, CCH N,
3 3 2 2
NCH CH N, CH N(C) ).
2
CH2
2
2
2
NH CH CH NH + 2 CH (CH ) Br
2
2
2
2
3
2 11
CH2
HN (CH2)11CH3
Measurements
Surface Tension
Surface Tension Measurements
0
Scheme 4 The synthesis of N,N -didodecyl ethylenediamine
ethylenediamine was 69%. The structures were confirmed by
1
FTIR and H-NMR. The characteristic bands were located at
-1
-1
-1
2
920.73 cm and 2855.93 cm (tC–H), and 1416.80 cm
1
(
dC–H). H-NMR (D-DMSO, TMS, 50 °C): d 0.865 (t, 6H,
CH C), 1.240 (m, 40H, –(CH ) –), 1.574 (m, 2H, NH), 2.496
The tensiometer was adjusted until the surface tension of
distilled water/air was measured as 71.0 mN/m. The sur-
face tension of the sample solution was determined, in turn,
from high to low concentrations.
3
2 10
(
m, 4H, CH N), 2.919 (m, 4H, NCH CH N).
2 2 2
0
In the second step, N,N -didodecyl ethylenediamine
(
0.01 mol) was dissolved in 50 mL ethanol, and then added
According to the critical micelle concentration (CMC),
into a 250 mL three-necked flask at 80 °C. 3-Chloro-1-
N,N-dimethyl) propylamine (0.022 mol) and potassium
ccmc and c-logC curves, the other important properties of
surfactants, such as pC20, Cmax and Amin, can be obtained
by calculation or linear fitting.
(
iodide (0.022 mol) were dissolved in ethanol. This solution
was added slowly into the three-necked flask by a constant
pressure funnel, and the mixture was constantly stirred for
about 24 h (Scheme 5). After the reaction, the mixture was
cooled to room temperature. The solvent was removed by
vacuum distillation and the solid product was washed three
times with ethanol. Finally, the products were obtained by
drying at 50 °C for 24 h. The yield was 54% for the final
C
max is the saturation adsorption of surfactant molecules
2
in mol/1000 m at the gas–liquid interface, which is
obtained here by the Gibbs isothermal adsorption equation.
À1 dc
Cmax
¼
;
ð1Þ
nRT d ln C
-
1
where c is the equilibrium surface tension in mN m , R is
the gas constant [8.314 J/(mol K)], T is the absolute tem-
perature, C is the surfactant concentration, and (dc/dlnC) is
the slope in the surface tension isotherm when the con-
centration is near the CMC. The value of n (the number of
species at the interface whose concentrations change with
the surfactant concentration) is taken as 1 for an equimolar
ratio of surfactant anion and counteraction at interface, in
the absence of extra electrolyte. In order to extract the
0
0
product N,N -di(N,N-dimethyl propylamine)-N,N -didode-
cyl ethylenediamine. The structures were confirmed by
1
FTIR and H-NMR. The characteristic bands were located
-
1
-1
-1
at 2917.14 cm and 2843.59 cm (tC–H), 1414.63 cm
(
-
1
1
dC–H), and 1330.64 cm
(tC–N). H-NMR (D-DMSO,
TMS, 50 °C): d 0.897 (t, 6H, CH C), 1.273 (s, 4H,
3
CCH C CC), 1.25 (d, 32H, CC(CH ) CCN), 1.377 (s, 4H,
2
8
2 8
C CH CN), 1.482 (s, 4H, NCCH CN), 2.159 (t, 12H,
1
0
2
2
Scheme 5 The synthesis of
0
CH3
N,N -di(N,N-dimethyl
0
HN (CH ) CH
CH (CH ) N CH CH CH N
2
11
3
3
2 11
2
2
2
propylamine)-N,N -didodecyl
ethylenediamine
CH3
CH3
CH2
CH2
CH2
+
2 ClCH CH CH N
2 2 2
CH2
CH3
CH3
CH3
HN (CH ) CH
3
2
11
CH (CH ) N CH CH CH N
3
2 11
2
2
2
1
23

1
486
J Surfact Deterg (2017) 20:1483–1489
minimum surface area occupied by a surfactant molecule,
2
Amin (nm ), at the air–water interface when the surface
70
adsorption was saturated [15], Eq. (2) was used,
6
5
4
0
0
0
1
Amin ¼ À
ð2Þ
NACmax
2
where NA is Avogadro’s constant (6.02 9 10 mol ).
2
Amin is in nm .
3
-1
pC20 is the efficiency of surfactant, which can be charac-
terized by the ogarithm of the surfactant concentration C20 at
-
1
30
which the surface tension of water is reduced by 20 mN m
.
The pC (pC = -logC ) value measures the efficiency of
20
2
0
20
aggregation of surfactant at the air–water interface; the larger
20
-5.5
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
the value of pC , the greater the tendency of the surfactant to
2
0
logC
adsorb at the air–water interface and to form micelles, and the
more efficiently it reduces the surface tension [16]. Equa-
tion (3) was used to obtain pC ,
Fig. 1 The curve of c-logC of C12MAEd
2
0
c À c À 20
0
cmc
pC20 ¼
À log CMC
ð3Þ
Table 1 CMC and ccmc
2
:303nRTCmax
Surfactant
CMC (mol/L)
ccmc (mN/m)
where c is surface tension of pure water at 298.15 K, the
0
-
1
-4
-3
value is 71.27 mN m . ccmc is the surface tension at the
C12MAEd
3.76 9 10
1.43 9 10
1.6 9 10
9.8 9 10
27.8
27.1
40
-
1
CMC in mN m
.
EBAIBs [18]
-
2
3
C
12
H
H
25N(CH
3 3
) Br
-
Foaming Properties
C
12
25SO Na
3
38
In our experiment, the blender method was used to test
foaming ability of the test material. 200 mL of sample
solution was added into a measuring cup. The concentra-
tions of surfactants in the foaming study were 0.1, 0.2, 0.3,
Table 2 Surface property parameters of the product
2
10
max 9 10 (mol/cm
-2
)
Surfactant
C H N
PC20
5.01
A
min (nm )
C
0
.4, 0.5 and 0.6 wt%. Foam was generated by high-speed
0.787
2.11
3
6 78 4
(
4000 rpm) stirring of the solutions for 60 s using a Waring
Blender at 25 °C [16]. The time required for 100 mL liquid
phase to form was recorded as t1/2, which is the drainage
half-life of the bubble.
micelle concentration (CMC) of the surfactant could be
derived from the inflection point of the curve in the graph.
The corresponding surface tension of the surfactant was
ccmc
.
Conductivity Measurements
0
of N,N -di(N,N-dimethyl
Values of CMC and c
cmc
0
propylamine)-N,N -didodecyl ethylenediamine are listed in
0
In this paper, the conductivities of test material solutions
were measured with a DDS-11A conductometer. During
the experiment, the temperature of the aqueous solution
was kept constant at 25.0 ± 0.1 °C. The concentration of
Table 1. The c
of N,N -di(N,N-dimethyl propylamine)-
cmc
0
N,N -didodecyl ethylenediamine is between the traditional
single chain cationic surfactant and the traditional Gemini
cationic surfactant. It has a similar ccmc value and a lower
CMC value asthe switchable Gemini surfactant, EBAIBs
-
1
the switchable surfactant was 0.01 mol L . CO gas was
2
bubbled through the solution for 80 min, followed by N2
for 80 min [17].
[
18].
In Table 2 we see that, compared with a traditional
single chain cationic surfactant with the same number of
carbon atoms, the synthesized Gemini surfactant had better
surface active parameters, pC20 value slightly increased,
Amin value decreased and Cmax value became larger. This
indicates that the synthesized surfactant had strong
adsorption on gas–liquid interface and high efficiency in
reducing surface tension.
Results and Discussion
Surface Tension
The curve of surface tension vs concentration (on a log
scale) in water/air are illustrated in Fig. 1. The critical
1
23

J Surfact Deterg (2017) 20:1483–1489
1487
7
6
5
4
3
2
0
0
0
0
0
0
0
20
40
60
80
V(L)
Fig. 3 The conductivity of surfactant solution
Fig. 2 The curve of c-volume of CO
2
From Fig. 3 we see that the initial state of the solution
In order to investigate the influence of different CO2
conductivity values was slightly higher than zero. As the
0
volumes on surface tension under a constant concentration
CO was continuously bubbled into the solution, N,N -
2
of surfactant, 10 L of CO gas were bubbled into a 0.01
2
0
di(N,N-dimethyl propylamine)-N,N -didodecyl ethylenedi-
0
mol/L concentration of surfactant solution every time for
amine reacted with CO to generate N,N -di(N,N-dimethyl
2
1
5 min to make sure a complete reaction of CO and the
2
0
propylamine)-N,N -didodecyl ethylenediamine bicarbonate
quaternary ammonium cationic surfactant, complete dis-
solution. The curve of surface tension vs the volume of
(
CO is shown in Fig. 2.
2
sociation). The conductivity increased rapidly until the
Because the switchable surfactant had a very low solu-
maximum value was attained, but with bubbling N gas
2
bility without bubbling CO , the surface tension of the
2
into the system, the bicarbonate was decomposed to the
initial state and became neutral non-ionic compounds. The
conductivity in solution then decreased rapidly and grad-
ually returned to its initial value. The repeated conductivity
experiments confirmed that the synthesis of surfactant was
CO -responsive, that is, the surfactant was CO -triggered
switchable surfactant solution/air is almost the same as that
of pure water/air. When the volume of CO bubbled was
2
about 20 L, the surface tension underwent a big change,
and after the volume of bubbled CO was about 60 L,
2
surface tension stopped changing. That indicated that the
tertiary amine structure transformation to bicarbonate had
been completed, and that the transformation of non-sur-
factant to surfactant had been completed.
2
2
and switchable.
Reversibility of Foam Property
There was no foam observed before the CO was bubbled
2
CO /N Switchable Properties
2
2
into these solutions. When the CO was bubbled into the
2
solutions and rotated for 60 s in the blister apparatus, foam
was produced. After the foam disappeared completely, N2
was introduced into the solutions and rotated for 60 s in the
blister apparatus; no foam was observed in the cylinders.
Results are shown in Fig. 4.
Reversibility of Conductivity
The initial conductivity of N,N’-di(N,N-dimethyl propy-
0
lamine)-N,N -didodecyl ethylenediamine was measured in
-
1
0
.01 mol L solution at 25 °C. After that, the CO gas
2
With the increase of surfactant concentration, foam
volume increased. When the concentration reached a cer-
tain value, foam volume achieved a maximum value. When
we continued to increase the concentration of surfactant,
the foam volume no longer increased and gradually stabi-
lized. The maximum foam volume observed was 650 mL.
The likely explanation for this phenomenon could be that
as the surfactant concentration in the solution was first
increased, there was a greater tendency to decrease the
was bubbled at the speed of 1 L/min and the conductivity
was recorded every 5 min. When the reaction in the system
was in balance and the conductivity value was leveling off,
N continued to be bubbled into the solution at the speed of
2
1
L/min and r, the value of conductivity, was recorded
until the conductivity reached a minimum value [9]. The
experiment was run in triplicate. The curve of conductivity
is shown in Fig. 3.
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J Surfact Deterg (2017) 20:1483–1489
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fonate-3-alkylether-propoxy) propanes. J Surfactants Deterg.
2013;16(5):665–72.
0
0
that N,N -di(N,N-dimethyl propylamine)-N,N -didodecyl
ethylenediamine had reversible surface tension when CO2
and N were cyclically bubbled into the solution. A con-
2
16. Zhou M, Xia L, He Y, Zhang L, Qiao X, Zhong X. Synthesis of
new Salt-Resistant sulfonate Gemini surfactants with hydroxyl
groups. J Surfactants Deterg. 2015;18(2):303–8.
0
ductivity reversibility experiment confirmed that the N,N -
0
di(N,N-dimethyl propylamine)-N,N -didodecyl ethylenedi-
1
2
7. Lu HS, Guan XQ, Dai SS, Huang ZH. Application of CO -
amine had CO /N switchable performance. After further
2
2
Triggered switchable surfactants to form emulsion with xinjiang
heavy oil. J Dispers Sci Technol. 2014;35(5):655–62.
8. Lu H, He Y, Huang ZY. Synthesis and properties of a series of
optimization of the synthesis process, applications for the
tertiary amine CO /N -switchable surfactant will be
1
2
2
2
CO switchable Gemini imidazolium surfactants. Tenside Sur-
factants Deterg. 2014;51(5):415–20.
promising.
Acknowledgements The authors would like to thank the National
Natural Science Foundation of China (No. 51274210) for financial
support. This research was also supported by Project of Sichuan
Province College Key Laboratory of Oil and Gas Field Materials (No.
X151516KCL33).
Ming Zhou received his B.Sc., M.Sc., and Ph.D. degrees from the
Southwest Petroleum University in Chengdu of the PR China and
worked at the School of Materials Science and Engineering at
Southwest Petroleum University as a research chemist in 2002, and he
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J Surfact Deterg (2017) 20:1483–1489
1489
is an associate professor at the State Key Laboratory of Oil and Gas
Reservoir Geology and Exploitation. His research field is the
synthesis and applications of surfactants and polymers.
Engineering. His specialty is the research and application of oil and
gas materials.
Sisi Li is a postgraduate from the Southwest Petroleum University in
China, and is studying at the School of Materials Science and
Engineering. Her specialty is the research and application of oil and
gas materials.
Gang Wang studied at the School of Materials Science and
Engineering at Southwest Petroleum University as a postgraduate.
He is majoring material physical chemistry.
Yaoyang Xu studied at the School of Materials Science and
Engineering at Southwest Petroleum University as a postgraduate.
His research field is the synthesis and applications of surfactants and
polymers.
Buhua Hu studied at the School of Materials Science and Engineer-
ing at Southwest Petroleum University as a postgraduate. His research
field is the synthesis and applications of surfactants and polymers.
Yunlong Zhao studied at the School of Materials Science and
Engineering at Southwest Petroleum University as a postgraduate. He
is majoring polymer material and engineering.
Ze Zhang is a postgraduate from the Southwest Petroleum University
in China, and is studying at the School of Materials Science and
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