Synthesis, Characterization, and Viscosification of Amidosulfobutaine and Zwitterionic Gemini Surfactants

Article abstract of DOI:10.1002/jsde.12474

The viscoelastic surfactants (VES)-based acid diverters are frequently used to divert acid flow from high-permeability layers into low-permeability for enhanced overall productivity of the treated well. In general, an optimum VES-based system possesses advantages of decrease in absorption loss, damage of reservoir, and improved adaptability of active agents to high salinity. Herein, we report the synthesis of three new zwitterionic gemini surfactants (1–3) and previously known amidosulfobutaine (C₁₈AMP3SB) has been accomplished for the investigation of diverting acid performance. The synthesis of these surfactants was achieved by the amidation of the acid chlorides of commercially available fatty acids with 3-(dimethylamino)-1-propylamine followed by subsequent reactions with appropriate sultone or ethyl 4-bromobutanoate. The synthesized surfactants were well characterized by spectroscopic methods including IR and NMR spectroscopy. The thermogravimetric analysis (TGA) results suggested that surfactants (1–3) and C₁₈AMP3SB possess excellent thermal stability, with no appreciable loss of mass up to 300°C. The viscosity measurements of the neat surfactants (1–3) and C₁₈AMP3SB were performed under various temperatures, in the presence of different concentration of calcium chloride salt with the aid shear viscosimetry. The analysis revealed that the viscosity of neat C₁₈AMP3SB increases with increase in concentration of CaCl₂. With 10% CaCl₂ solution, the viscosity was increased from 7.5 to 33.55 cPs, whereas in 20% CaCl₂ the viscosity reached to 102 cPs with rise in temperature from ambient to 90°C. Moreover, the viscosity of neat surfactants (1–3) did not exhibit any appreciable viscosity change under the experimental conditions. However, the mixture of surfactants (1–3) each in combination with C₁₈AMP3SB (1:1) displayed significant upsurge in the viscosity, up to more than 10 folds.

Full text of DOI:10.1002/jsde.12474

J Surfact Deterg (2020)
DOI 10.1002/jsde.12474
ORIGINAL ARTICLE
Synthesis, Characterization, and Viscosification of
Amidosulfobutaine and Zwitterionic Gemini Surfactants
Muhammad Mansha1 · Nisar Ullah1 · Rajendra A. Kalgaonkar2 · Nour Baqader2
Received: 16 August 2020 / Revised: 14 October 2020 / Accepted: 29 October 2020
© 2020 AOCS
Abstract The viscoelastic surfactants (VES)-based acid
diverters are frequently used to divert acid flow from high-
permeability layers into low-permeability for enhanced
overall productivity of the treated well. In general, an opti-
mum VES-based system possesses advantages of decrease
in absorption loss, damage of reservoir, and improved
adaptability of active agents to high salinity. Herein, we
report the synthesis of three new zwitterionic gemini sur-
factants (1–3) and previously known amidosulfobutaine
(C18AMP3SB) has been accomplished for the investigation
of diverting acid performance. The synthesis of these sur-
factants was achieved by the amidation of the acid chlo-
rides of commercially available fatty acids with
3-(dimethylamino)-1-propylamine followed by subsequent
neat C18AMP3SB increases with increase in concentration
of CaCl2. With 10% CaCl2 solution, the viscosity was
increased from 7.5 to 33.55 cPs, whereas in 20% CaCl2 the
viscosity reached to 102 cPs with rise in temperature from
ambient to 90ꢀC. Moreover, the viscosity of neat surfac-
tants (1–3) did not exhibit any appreciable viscosity change
under the experimental conditions. However, the mixture
of surfactants (1–3) each in combination with C18AMP3SB
(1:1) displayed significant upsurge in the viscosity, up to
more than 10 folds.
Keywords Zwitterionic gemini surfactants ꢁ Viscoelastic
surfactants ꢁ Heat stimuli response ꢁ Oil well stimulation
reactions
with
appropriate
sultone
or
ethyl
J Surfact Deterg (2020).
4-bromobutanoate. The synthesized surfactants were well
characterized by spectroscopic methods including IR and
NMR spectroscopy. The thermogravimetric analysis (TGA)
results suggested that surfactants (1–3) and C18AMP3SB
possess excellent thermal stability, with no appreciable loss
of mass up to 300ꢀC. The viscosity measurements of the
neat surfactants (1–3) and C18AMP3SB were performed
under various temperatures, in the presence of different
concentration of calcium chloride salt with the aid shear
viscosimetry. The analysis revealed that the viscosity of
Introduction
Crude oil is considered one of the most readily accessible
sources of energy. It constitutes a crucial source of raw
materials required for the chemical industries, on which
daily life relies upon. Well stimulation techniques enable
improved extraction of hydrocarbon reserves that the con-
ventional recovery processes, such as gas or water displace-
ment are unable to achieve. Matrix stimulation is one of the
well stimulation techniques wherein an acidic fluid or sol-
vent is injected into a formation at a pressure lower than
the fracturing pressure. Carbonate rock acidification results
in dissolution of carbonate minerals, producing new worm-
holes or channels that bypass damage. An optimum injec-
tion rate is required to attain a breakthrough with a full
wormhole formation by smallest volume of acid. In addi-
tion, stimulation of the target zone requires proper
* Muhammad Mansha
manshachohan@kfupm.edu.sa
* Nisar Ullah
nullah@kfupm.edu.sa
1
Chemistry Department, King Fahd University of Petroleum &
Minerals, Dhahran, 31261, Saudi Arabia
2
Production Technology Division, EXPEC Advanced Research
Center, Saudi Aramco, Dhahran, 31311, Saudi Arabia
J Surfact Deterg (2020)

J Surfact Deterg
placement of acid, which in turn depends upon a relatively
close permeability ratio (Hoefner and Fogler, 1988, 1989).
Nevertheless, studies have suggested that the effectiveness
of acid treatment becomes limited because acid tends to
flow primarily into the most permeable zones, leaving the
rest of the reservoir pores unaffected or poorly affected by
the acid. In addition, due to difference in wettability the
reaction of acid with carbonate rocks in water-saturated
zones is faster than that with oil-saturated rocks which
leads to enhanced acid activity in water zones, resulting in
their increased injectivities (Bulgakova et al., 2014). There-
fore, acid diversion into low-permeability layers by limiting
fluid flow into high-permeability layers would enhance the
coverage of the acid exposure zone and result in the overall
productivity of the treated well (Glasbergen and
Buijse, 2006; Kalfayan and Martin, 2009). Polymer-based
viscoelastic fluids have been frequently used as flow
diverters (Kalfayan and Martin, 2009). However, these
fluids suffer from limitation such as increasing the viscosity
of the acid which in turn leads to decreasing injection rate.
(Lynn and Nasr-El-Din, 2001; Nasr-El-Din et al., 2002,
2004b).
Viscoelastic-surfactant (VES)-based acids can offer solu-
tion to mitigate this problem (Nasr-El-Din et al., 2004a,
2006a). VES-based systems employ specialized surfactant
that in acid solution forms spherical micelles when present
above its critical micelles concentration (CMC). The stimu-
lation of carbonate reservoir with hydrochloric acid leads to
decrease in the pH (~ pH 2) and increase in the concentra-
tions of calcium ions, which in turn force the surfactant
monomers to form rod-shaped micelles. As a result, the vis-
cosity of the fluid is significantly increased, which acts as a
temporary barrier to divert acid into untreated low-
permeability zones. However, in the presence of high-
viscosity hydrocarbons and at slightly higher pH (pH 3–4),
when processing is over, the high-viscosity barrier col-
lapses (Taylor et al., 2003).
In the recent past, several studies attested the efficacy of
VES-based system as acid diverters (Al-Ghamdi
et al., 2010; Gomaa et al., 2012; Yu et al., 2010). Chang
et al. have reported the use of carboxybetain VES as self-
diverting acid systems, which successfully diverted acid
from high-permeability core into the low-permeability core
(Al-Ghamdi et al., 2014). In another report, the addition of
polyelectrolyte into self-diverting acid systems based on
VES resulted in the increase in the thermal stability of the
fluids. The rheological properties of the fluid were adjusted
by customizing surfactant concentration, temperature, and
pH of fluid. The application of self-diverting acid systems
was successfully demonstrated in the oil producing wells
without emulsion concerns (Alleman et al., 2003). In other
studies, parallel flow tests were performed by deploying
cationic VES (Nasr-El-Din et al., 2009) and amine oxide
VES (Nasr-El-Din et al., 2006b). It was observed that the
use of these self-diverting acid systems led to increased
effluent volume through the lower-permeability core, which
in turn allowed preferential acid breakthrough in the lower-
permeability core as compared to higher-permeability core.
Likewise, carboxybetaine VES-based acid was used by
Tardy et al. to develop the reactive flow of self-diverting
acid. They suggested that wormhole penetration and zonal
coverage are the most important characteristics of
self-diverting acids. Moreover, the viscosity buildup in the
matrix occurs around wormhole, which are virtually
infinitely conductive (Al-Ghamdi et al., 2014). Similarly,
Al-Ghamdi et al. also deployed carboxybetaine VES-based
acid and concluded that the rate of acid injection is crucial
to obtain the maximum acid diversion efficiency
(Al-Ghamdi et al., 2014).
Similarly, sulfobetaine and hydroxyl sulfobetaine have
been employed as thickeners in self-diverting acids. The
sulfonate function is known to assist in rodlike micelles for-
mation and also reduces the concentration required for
CMC (Wang et al., 2014). On the other hand, the two
hydrophilic groups in gemini surfactants permit water solu-
bility, self-assembling properties, and tolerance for hard
water (Kabir and Koya, 2010). Zhang et al., have recently
developed a zwitterionic gemini surfactant to evaluate its
acid diverting performance (Zhang et al., 2019).
Commonly used zwitterionic surfactants-based VES mole-
cules are neutral in nature, due to the presence of equal num-
ber of positive and negative charges. Consequently, their
adsorption to reservoir minerals is lower. However, under
extreme acidic conditions protonation of anionic function of
zwitterionic surfactant may result in cationic moiety and hence
leads to higher adsorption to reservoir minerals
(Holmberg, 2002). On the other hand, important structural
characteristics features of zwitterionic gemini surfactants
include large number of hydrophilic groups, which enabled
them to self-assemble for their enhanced viscofication. The
zwitterionic gemini surfactants enjoy the advantages of
decreasing absorption loss, damage of reservoir, and improved
adaptability of active agents to high salinity (Kamal, 2016;
Raoul Zana, 2004). Through this research article, we report
the synthesis and viscosification of new zwitterionic gemini
surfactants (1–3) individually and in combination with zwit-
terionic surfactant (C18AMP3SB).
Materials and Methods
Materials
All the chemicals like sebacic acid (99%), 3-(dimethylamino)-
1-propylamine (99%), 1,3-propanesultone (≥99%), 1,4-butane
J Surfact Deterg (2020)

J Surfact Deterg
sultone (≥99%), stearic acid (reagent grade, 95%), ethyl
4-bromobutyrate (95%), CaCl2 (anhydrous, powder, 99.99%)
were purchased from Sigma-Aldrich and used as received
without further purifications. The stock solutions of CaCl2
were prepared in deionized water. VES molecules and their
acetone was evaporated under vacuum and the product was
successively washed with n-hexane (20 mL) and diethyl
ether (2 × 20 mL) and dried under vacuum in rotary evapo-
rator to obtain the title compound 10 as white solid (85%).
1H NMR [D2O] = δ 1.28 (m, 8H), 1.56 (m, 4H), 1.90–1.99
(m, 8H), 2.15–2.41 (m, 12H), 3.08 (s, 12H), 3.21–3.30 (m,
12H). 13C NMR [CDCl3] = δ 18.95, 22.14, 25.22, 28.11,
33.32, 35.68, 35.88, 44.02, 50.66, 61.57, 63.46, 177.53,
180.53. FTIR (cm−1) = 3354.99, 3293.41, 2972.37,
2937.59, 1651.13, 1547.90, 1487.79, 1170.46, 1032.04,
727.08. C25H50 Br2N4O6 (660.21): calcd.: C 45.32, H 7.61,
N 8.46 found: C 44.64, H 8.03, N 8.30.
1
intermediates were characterized by H and 13C NMR on a
500 MHz spectrometer (JEOL JNM-LA, JEOL USA Inc.)
and Infrared spectra on FTIR spectrophotometer (Perkin
Elmer 16F PC, Perkin Elmer Inc. USA).
The viscosity of VES at different temperatures was
recorded by a Brookfield Rheometer DV3T coupled with
thermosel via programable temperature controller (Ametek,
USA). Thermogravimetric analysis (TGA) was measured
on SDT Q600 (V20.9 Build 20) thermal analyzer.
Synthesis of 4,4,16,16-tetramethyl-9,11-dioxo-
4,8,12,16-tetraazanonadecane-4,16-diium-1,19
disulfonate (1)
Synthesis of Surfactants
To a solution of compound 6 (0.43 g, 1.17 mmol) in ethyl
acetate (15 mL) 1,3-propane sultone 7 (0.48 g, 3.49 mmol)
and the reaction was refluxed overnight. The solid formed
was filtered, washed with plenty of ethyl acetate and diethyl
ether, and then dried under vacuum in rotary evaporator to
Synthesis of Gemini Surfactants
Synthesis of N1,N10-bis(3-(dimethylamino)propyl)
decanediamide (6)
1
To a cold thionyl chloride (10 mL) at 0 ꢀC was added
sebacic acid 4 (5.0 g, 24.72 mmol) portion-wise with con-
tinuous stirring in the reaction flask. After completion of
the addition, the temperature was slowly raised to room
temperature and the stirring was continued overnight. The
volatile was then evacuated under vacuum and the product
acid chloride was taken in CH2Cl2 (50 mL) and cooled to
obtain surfactant 1 a white solid (Yield = 93%). H NMR
[D2O] = δ 1.15–1.25 (m, 8H), 1.44 (m, 4H), 1.87 (t, 4H),
2.07 (t, 4H), 2.11 (t, 4H), 2.82 (t, 4H), 2.97 (s, 12H), 3.14
(t, 4H), 3.20 (t, 4H), 3.35 (t, 4H). 13C NMR [CDCl3] = δ
18.11, 22.23, 225.24, 35.87, 47.15, 50.70, 61.85, 62.18,
177.56. FTIR (cm−1) = 3303.34, 2927.54, 2844.68,
1669.76, 1555.30, 1486.92, 1479.07, 1156.97, 1024.45,
929.32, 794.55, 682.02. C26H54 N4O8S2 (614.86): calcd.: C
50.79, H 8.85, N 9.11; found: C 50.42, H 9.05, N 8.90.
0
ꢀC followed by the slow addition 3-(dimethylamino)-
1-propylamine 5 (6.31 g, 61.8 mmol) and triethylamine
(20.6 mL, 148 mmol). After completion of the addition, the
stirring was continued overnight at room temperature. The
volatiles were then evaporated under reduced pressure in
rotary evaporator. The residues were triturated with methanol
and the solid was filtered then dried under reduced pressure
using rotary evaporator to get compound 6 as white solid
Synthesis of 5,5,17,17-tetramethyl-10,12-dioxo-
5,9,13,17-tetraazahenicosane-5,17-diium-
1,21-disulfonate (2)
Following same procedure adopted for the synthesis of 1,
surfactant 2 was synthesized by the reaction of compounds
6 and 8 white solid (88%).
1
(90%). H NMR [CDCl3] = δ 1.255–1.302 (m, 8H), 1.577
1H NMR [D2O] = δ 1.17–1.25 (m, 8H), 1.45 (m, 4H),
1.67 (t, 4H), 1.78 (t, 4H), 1.86 (t, 4H), 2.11 (t, 4H), 2.18 (t,
4H), 2.83 (t, 4H), 2.94 (s, 12H), 3.14–3.23 (m, 12H). 13C
NMR [CDCl3] = δ 20.82, 21.07, 22.23, 25.29, 28.18,
35.73, 35.91, 43.59, 49.94, 50.74, 61.70, 63.42, 177.55.
FTIR (cm−1) = 3300.66, 2919.72, 2854.78, 1666.74,
1550.05, 1496.05, 1469.57, 1176.17, 1038.42, 956.74,
795.33, 686.20. C28H58 N4O8S2 (642.91): calcd.: C 52.31,
H 9.09, N 8.71; found: C 51.80, H 9.25, N 8.57.
(m, 4H), 1.637 (t, 4H), 2.121 (t, 4H), 2.280 (s, 12H), 2.367 (t,
4H), 3.319 (t, 4H), 6.948 (b, NH). 13C NMR [CDCl3] = δ
25.68, 26.14, 29.19, 36.89, 39.20, 45.38, 58.60, 173.04. FTIR
(cm−1) = 3303.67, 2921.83, 2852.83, 2811.75, 1635.01,
1538.76, 1468.29, 1379.05, 1238.83, 1100.88, 1041.46,
830.65, 714.41. C20H42N4O2 (370.58): calcd.: C 64.82, H
11.42, N 15.12; found: C 63.99, H 11.59, N 14.82.
Synthesis of N,N0-((malonylbis(azanediyl))bis(propane-
3,1-diyl))bis(4-ethoxy-N,N-dimethyl-4-oxobutan-
1-aminium) (10)
To a solution of compound 6 (3 g, 8.1 mmol) in dry ace-
tone (30 mL) was added 1-bromo ethyl butanoate
9 (3.45 g, 17.81 mmol) and the reaction was refluxed for
48 h. Upon completion of the reaction (TLC analysis), the
Synthesis of mono ((1-carboxylato-4,4,16,16-tetramethyl-
9,11-dioxo-4,8,12,16-tetraazaicosan-4,16-diium-20-oyl)
sodium(III)) monosodium monoxide (3)
To a solution of surfactant 10 (2.59 g, 3.42 mmol) MeOH
(20 mL) was added a solution of NaOH (0.3 g 7.53 mmol
J Surfact Deterg (2020)

J Surfact Deterg
Scheme 1 Synthesis of zwitterionic gemini surfactants 1–3
in 3 mL H2O) dropwise and the reaction mixture was
stirred overnight at room temperature. Upon the completion
of the reaction (TLC analysis), volatiles were removed
under vacuum in rotary evaporator and trituration of the
resultant residues with diethyl ether yielded to desired sur-
factant 3 very light yellow solid (95%). 1H NMR [D2O] = δ
Scheme 2 Synthesis of amidosulfobetaine surfactant (C18AMP3SB)
J Surfact Deterg (2020)

J Surfact Deterg
Fig 1 TGA curves of gemini surfactants (1–3) and C18AMP3SB
Fig 3 The apparent viscosity of the C18AMP3SB & 1 (1:1) with
CaCl2 solutions (10%, 20%, and 30%) versus shear rate at different
temperatures
1.11 (t, 6H), 1.14–1.16 (m, 8H), 1.43 (m, 4H), 1.85–1.89
(t, 8H), 2.10 (t, 4H), 2.36 (t, 4H), 2.95 (s, 12H), 3.11–3.18
(m, 12H), 4.03 (m, 4H) 13C NMR [CDCl3] = δ 13.27,
17.41, 22.22, 25.26, 28.17, 30.05, 35.71, 35.85, 50.84,
Results and Discussion
61.46,
61.95,
62.68,
174.39,
177.48.
FTIR
(cm−1) = 3381.46, 2915.11, 2884.58, 1728.47, 1651.86,
1486.84, 1376.99, 1181.46, 1033.89, 724.72. C28H54
Na2O6 (588.38): calcd.: C 57.12, H 9.25, N 9.52; found: C
56.67, H 9.43, N 9.75.
Synthesis and Characterization of Zwitterionic Gemini
Surfactants
The synthesis of zwitterionic gemini surfactants (1–3) was
accomplished as outlined in Scheme 1. The synthesis of
these surfactants required the preparation of the key inter-
mediate 6, which was synthesized by condensing diacid
chloride, generated by the reaction of sebacic acid (4) with
Synthesis of C18AMP3SB
Synthesis of C18AMP3SB was achieved as per earlier
reported procedures. The spectral data coincided with the
previously reported material (Chu and Feng, 2009).
Fig 4 The apparent viscosity of the C18AMP3SB and 2 (1:1) with
CaCl2 solutions (10%, 20%, and 30%) versus shear rate at different
temperatures
Fig 2 The apparent viscosity of the C18AMP3SB with CaCl2 solu-
tions (10%, 20%, and 30%) versus shear rate at different temperatures
J Surfact Deterg (2020)

J Surfact Deterg
Fig 5 The apparent viscosity of C18AMP3SB and 3 (1:1) with CaCl2 solutions (10%, 20%, and 30%) versus shear rate at different temperatures
Fig 6 Effect of temperature on viscoelastic surfactants at shear rate of 85 s−1 in (a) CaCl2-10% (b) CaCl2-30% (c) CaCl2-20%
thionyl chloride, with 3-(dimethylamino)-1-propylamine
(5) in dichloromethane solvent in 90% yield.
Condensation of diamine (6) with 1,3-propanesultone (7)
or 1,4-butanesultone (8) produced surfactants 1 and 2,
respectively. Similarly, reaction of 6 with 4-bromoethyl but-
anoate (9) in refluxing acetone yielded 10, which was hydro-
lyzed under basic conditions to generate the desired surfactant
3 in 90% overall yield from 6 (Scheme 1).
J Surfact Deterg (2020)

J Surfact Deterg
Similarly, the 1H NMR spectra of surfactants (1–3)
showed downfield shift for the methyl protons attached to
the quaternary nitrogen ((R)2N(CH3)2). The peak at δ 2.22
in 6 was shifted to between δ 2.90 and 3.069 in the case of
surfactants (1–3). Moreover, 13C NMR spectra of surfac-
tants (1–3) exhibited a clear shift for methylene carbons
attached to quaternary nitrogen (-CH2-N+(CH3)2-CH2-), at
between δ 61.81 and 63.50. Furthermore, peaks due to the
carbonyl carbons of amide group were found at δ 177.05.
In addition, surfactants (3) also displayed peak due to car-
bonyl carbon at δ 180.53.
Thermogravimetric Analysis of Surfactants
The thermal stability of VES molecules at high temperature
is very important. The stability of these molecules was
assessed by thermogravimetric analysis (TGA). TGA was
performed on SDT Q600 (V20.9 Build 20) thermal ana-
Fig 7 Stability test of viscosification for VES molecules in CaCl2-
20% at 90ꢀC under shear rate of 85 s−1
lyzer. In these analyses, samples were heated from room
−1
ꢀ
temperature to 700ꢀC at the rate of 10 C min rise by
purging nitrogen at a rate of 50 mL min−1. As evident from
Fig. 1, these surfactants demonstrated high thermal stability
and showed no appreciable loss of mass up to 300ꢀC. The
surfactants (1–3) showed the onset of decomposition tem-
peratures (Td) at 320, 340, and 310ꢀC, respectively. While
the onset of decomposition temperature for C18AMP3SB
was observed at 355ꢀC. An abrupt loss in weight above the
Td was realized that indicated the decomposition of the
main chain of surfactants (Fig. 1).
Synthesis and Characterization of C18AMP3SB
The synthesis of amidosulfobetaine surfactant 3-(dimethyl
(3-stearamidopropyl)ammonio)-propane-1-sulfonate
(C18AMP3SB) was achieved based on earlier reported pro-
cedures, as outlined in Scheme 2 (Chu and Feng, 2009). In
brief, refluxing the mixture of neat stearic acid (11) with
N,N-dimethyl-1,3-propanediamine (5) at 160ꢀC for 16 h
afforded the tertiary amine (12), which was then condensed
with 1,3-propanesultone (7) in ethyl acetate to produce the
desired surfactant C18AMP3SB in 86% overall yield from
11. The spectral data matched with the earlier reported
material (Chu and Feng, 2009).
Viscosification
The relationship of apparent viscosity of C18AMP3SB and
its mixture with gemini surfactants (1–3) each in different
concentrations of CaCl2 solutions (10–30%w/w) at varied
temperatures (RT-90ꢀC) with varying shear rates
(1–85 s−1) was studied. The amidosulfobetaine surfactant
C18AMP3SB showed significant changes in its apparent
viscosity in CaCl2 solutions (10, 20, and 30%w/w) at var-
ied temperature (RT-90ꢀC). The analysis revealed that the
viscosity kept increasing with increase in concentration of
CaCl2 from 10% to 20%. However, the viscosity sees a
drop when the concentration of CaCl2 solution was raised
to 30%. At a fixed shear rate of 85 s−1 and under different
temperature i.e., ambient temperature, 40 and 90ꢀC,
C18AMP3SB with 10% CaCl2 solution exhibited viscosi-
ties between 7.5 cPs and 33.55 cPs. Likewise, under similar
experimental conditions except changing the concentration
of CaCl2 solution to 20%, the viscosity ranged between
7.78 cPs and 102 cPs and for 30% CaCl2 solution; it was
observed to be between 5.75 cPs and 24.09 cPs (Fig. 2).
Similarly, the viscosity behavior of neat zwitterionic
gemini surfactants (1–3) were also studied in different
The chemical structures of all the intermediates and the
final surfactant products were confirmed by spectroscopic
methods. For instance, FT-IR spectrum of intermediate
6 displayed the presence of -N-H stretch at 3303 cm−1 and
amide carbonyl (–CH2–C=O–NH) stretching at 1635 cm−1
.
Similarly, the presence of methylene (–CH2–) stretching
bands (2915 cm−1 and 2884 cm−1) and bending vibrations
(1468 cm−1 and 1379 cm−1) suggested the presence of
alkyl chains. Likewise, the 1HNMR of intermediate
6 exhibited resonance at δ 3.30 due to the methylene pro-
tons attached to amide function (–CH2–NH(C=O)–), which
appeared at δ 3.30 and peaks for methyl protons attached to
tertiary nitrogen (–N(CH3)2) at
δ
2.22 (Hussain
et al., 2016). Moreover, the 13C NMR displayed peaks due
to the presence of carbonyl carbon of amide at δ 173.05
and methylene carbon attached to amide function (-CH2-
NH(C=O)-) δ 58.60. The spectrum also showed peak for
methyl carbons attached to tertiary nitrogen (-N(CH3)2) at δ
45.38. .
J Surfact Deterg (2020)

J Surfact Deterg
Fig 8 Gel breaking properties using diesel oil in CaCl2-20% at 90ꢀC (a) C18AMP3SB (b) C18AMP3SB + 1 (c) C18AMP3SB + 2 and (d)
C18AMP3SB + 3
concentrations of CaCl2 solutions (10–30%w/w) at varied
temperatures (RT-90ꢀC) with varying shear rates
(1–85 s−1). The results suggested that the none of gemini
surfactants (1–3) alone exhibit any appreciable viscosity
change under these experimental conditions. However, the
mixture of surfactants (1–3) each in combination with
C18AMP3SB (1:1) displayed significant upsurge in the vis-
cosity. The results suggested a trend in decrease in viscos-
ity with increasing shear rate, which suggested that the
solutions containing the mixture of C18AMP3SB and gem-
ini surfactants are non-Newtonian fluids. In other words,
the viscosity of the mixture of C18AMP3SB and gemini
surfactants decreases with increase in shear rate
(Figs. 1–4). Moreover, the mixture of surfactants (1–3)
each in combination with C18AMP3SB in CaCl2 solutions
demonstrated better shear rate resistance, which suggested
that the calcium ions encourage the formation of wormlike
micelles (rod-shaped micelles). For example, the mixture of
surfactant 1 with C18AMP3SB (1:1) showed up to 4–5
folds enhancement in viscosity. At a fixed shear rate of
85 s−1 and under different temperature i.e., ambient tem-
perature, 40 and 90ꢀC, the mixture in 10% CaCl2 solution
displayed viscosity ranging between 5.06 and 7.07 cPs.
Likewise, in 20% CaCl2 solution the viscosity varied from
3.31 to 14.6 cPs and for 30% CaCl2 solution it was
observed to between 6.2 and 9.77 cPs (Fig. 3).
Likewise, the mixture of surfactant 2 and C18AMP3SB
(1:1 wt/wt) at a fixed shear rate of 85 s−1 and under differ-
ent temperature i.e., ambient temperature, 40 and 90ꢀC,
with 10% CaCl2 solution showed viscosity in the range
J Surfact Deterg (2020)

J Surfact Deterg
between 3.61 and 13.13 cPs; for 20% CaCl2 solution the
viscosity varied from 5.05 to 36.33 cPs and for 30% CaCl2
solution 5.44 to 30.06 cPs (Fig. 4).
cleanup during hydrocarbon production. Any remaining
high viscosity gel will lead to damaging the reservoir by
blocking the hydrocarbon. To confirm the hypothesis, gel
breaking properties of neat surfactants and their mixtures
were studied by mixing them with diesel, from 1.53% to
15.66%, in the presence of 20% CaCl2 solution. These
results suggested that the viscosity of C18AMP3SB dropped
from maximum (102 cPs) to minimum (7.2 cPs) upon addition
of 5% diesel at 90ꢀC. Moreover, any further addition of diesel
led to enhance the viscosity again (Fig. 8a). Likewise, mixture of
surfactant 1 and C18AMP3SB (1:1 w/w) also displayed decline
in the apparent viscosity up to 11.02% followed by an increase
upon further increase in the diesel concentrations (Fig. 8b). Simi-
larly, the gel breaking of mixture of surfactant 2 and
C18AMP3SB (1:1 w/w) was decreased from 36.33 to 7.5 cPs
with rise in concentration of diesel up to 5.83%. However, the
viscosity then tends to increase with rise in any further diesel
concentration (Fig. 8c). Finally, a considerable change in viscos-
ity was also seen in the case of surfactant 3 and C18AMP3SB
(1:1 w/w). The gel breaking occurred with 11.02% of diesel
addition, which was then started increasing with any further
increase in diesel concentration (Fig. 8d).
Moreover, at a fixed shear rate of 85 s−1 and under dif-
ferent temperature i.e., ambient temperature, 40 and 90ꢀC,
the mixture of surfactant 3 and C18AMP3SB (1:1 wt/wt)
with 10% CaCl2 solution showed viscosity in the range
between 4.09 and 14.72 cPs; for 20% CaCl2 solution vis-
cosity varied from 3.35 to 37.62 cPs and for 30% CaCl2
solution, 2.82 to 35.22 cPs (Fig. 5).
Effect of Temperature on the Viscosity
As a stimulation fluid is pumped downhole it sees rise in the
temperature. The behavior of the fluid as a function of temper-
ature is an important parameter. Thus, it is pertinent to investi-
gate the effect of temperatures on the viscosity build up for
viscoelastic surfactants. The temperature dependence of the
new VES molecules was investigated over a temperature
range of ambient to 90ꢀC. It is assumed that the rise in the
temperature leads to increase in the thermal motion of the
molecules, which causes the network microstructure of visco-
elastic surfactants to transform into single wormlike micelles
(Mao et al., 2018). However, the presence of excessive Ca+2
ions on the surface of small micelles inhibits the recovery of
wormlike micelles and network structure. But, higher temper-
ature can contribute toward desorption of excessive Ca+2 ions
and thus can promote recovery of wormlike micelles and net-
work structure. The mechanism for heat response has been
well studied by Davies et al. on CTAB and salicylic acid sys-
tem (Davies et al., 2006). Another important effect of heating
was that the intense motion of hydrophobic chains promoted
the twining of surfactant for stronger network building (Mao
et al., 2018). Therefore, the neat C18AMP3SB and the mix-
tures of C18AMP3SB with surfactants (1–3) in varied concen-
tration of CaCl2 solutions (10–30%w/w) exhibited increase in
the viscosity with increase in temperature from ambient to
90ꢀC (Fig. 6).
Conclusions
Three new zwitterionic gemini surfactants (1–3) and a pre-
viously known amidosulfobutaine (C18AMP3SB) were
synthesized from commercially available fatty acids using a
straight-forward synthesis. The chemical structures of these
surfactants were characterized by spectroscopic methods
1
including H and 13C NMR, and IR spectroscopy. More-
over, these surfactants exhibited excellent thermal stability,
determined by TGA. At varied temperature and different
shear rates, the viscosity of mixture of zwitterionic gemini
surfactants (1–3) with amidosulfobutaine (C18AMP3SB)
showed promising buildup of viscosity. The individual
C18AMP3SB surfactant and its combinations with zwitter-
ionic gemini surfactants (1–3) performed best in the pres-
ence of 20% CaCl2 solution at 90ꢀC showing the apparent
viscosity of 102, 14.6, 36.33, 37.62 cPs, respectively. The
properties of these surfactants warrant their potential for a
possible use in various oilfield applications.
The stability of the viscosity of C18AMP3SB alone and
as a mixture in combination with surfactants (1–3) in CaCl2
solutions (20%w/w) under shear rate of 85 s−1 at 90ꢀC was
tested for one hour the mixtures of C18AMP3SB with sur-
factants (1–3) in CaCl2 solutions (20%w/w) under shear
rate of 85 s−1 at 90ꢀC was tested for one hour. The results
showed that there was no appreciable change in viscosity
with time and the viscosity remains stable throughout the
experiment (Fig. 7).
Conflict of Interest The authors declare that they have no conflict
of interest.
Gel Breaking Properties
References
It is hypothesized that the viscosified VES gel will break
once it encounters the produced hydrocarbon. It is impor-
tant that the VES gel viscosity gets reduced for better
Al-Ghamdi, A.H., Mahmoud, M.A., Hill, A.D., & Nasr-El-Din, H.A.
(2010) When do surfactant-based acids work as diverting agents?,
in Proceedings—SPE International Symposium on Formation
J Surfact Deterg (2020)

J Surfact Deterg
Damage Control. Society of Petroleum Engineers (SPE),
pp. 925–939. https://doi.org/10.2118/128074-ms
of Petroleum Engineers (SPE), pp. 1–16. https://doi.org/10.2118/
65386-ms
Al-Ghamdi, A. H., Mahmoud, M. A., Wang, G., Hill, A. D., & Nasr-
El-Din, H. A. (2014) Acid diversion by use of viscoelastic surfac-
tants: The effects of flow rate and initial permeability contrast. SPE
Journal, 19:1203–1216. https://doi.org/10.2118/142564-PA
Alleman, D., Qi, Q., & Keck, R. (2003) The development and suc-
cessful field use of viscoelastic surfactant-based diverting agents
for acid stimulation, in: International symposium on oilfield chem-
istry. Society of Petroleum Engineers. https://doi.org/10.2118/
80222-MS
Mao, J., Zhang, H., Zhang, W., Fan, J., Zhang, C., & Zhao, J. (2018)
Dissymmetric beauty: A novel design of heterogemini viscoelastic
surfactant for the clean fracturing fluid. Journal of Industrial and
Engineering Chemistry, 60:133–142. https://doi.org/10.1016/j.jiec.
2017.10.048
Nasr-El-Din, H. A., Alhabib, N. S., Al-Mumen, A. A.,
Jemmali, M., & Samuel, M. (2006a) A new effective stimulation
treatment for long horizontal Wells drilled in carbonate reservoirs.
SPE Production & Operations, 21:330–338. https://doi.org/10.
2118/86516-PA
Bulgakova, G. T., Kharisov, R. Y., Pestrikov, A. V.,
&
Sharifullin, A. R. (2014) Experimental study of a viscoelastic
surfactant-based in situ self-diverting acid system: Results and
interpretation. Energy & Fuels, 28:1674–1685. https://doi.org/10.
1021/ef4019542
Chu, Z., & Feng, Y. (2009) A facile route towards the preparation of
ultra-long-chain amidosulfobetaine surfactants. Synlett, 2009:
2655–2658. https://doi.org/10.1055/s-0029-1217973
Davies, T. S., Ketner, A. M., & Raghavan, S. R. (2006) Self-assembly
of surfactant vesicles that transform into viscoelastic wormlike
micelles upon heating. Journal of the American Chemical Society,
128:6669–6675. https://doi.org/10.1021/ja060021e
Glasbergen, G. & Buijse, M.A. (2006) Improved acid diversion
design using a placement simulator, in: SPE Russian oil and gas
technical conference and exhibition. Society of Petroleum Engi-
neers, pp. 569–579. https://doi.org/10.2118/102412-MS
Gomaa, A.M., Cutler, J., Qu, Q., & Cawiezel, K.E. (2012) Acid place-
ment: An effective VES system to stimulate high-temperature car-
bonate formations, in SPE Production and Operations Symposium,
Proceedings. Society of Petroleum Engineers, pp. 1112–1132.
https://doi.org/10.2118/157316-ms
Hoefner, M. L., & Fogler, H. S. (1988) Pore evolution and channel
formation during flow and reaction in porous media. AICHE Jour-
nal, 34:45–54. https://doi.org/10.1002/aic.690340107
Hoefner, M. L., & Fogler, H. S. (1989) Fluid-velocity and reaction-
rate effects during carbonate acidizing: Application of network
model. SPE Production Engineering, 4:56–62. https://doi.org/10.
2118/15573-PA
Holmberg, K. (2002) Handbook of applied surface and colloid chem-
istry. Australian Journal of Chemistry, 55:383–402.
Nasr-El-Din, H.A., Al-Habib, N.S., Jemmali, M., Lahmadi, A., &
Samuel, M., 2004a. A novel technique to acidize horizontal Wells
with extended reach, in SPE Annual Technical Conference and
Exhibition. Society of Petroleum Engineers. https://doi.org/10.
2118/90385-MS
Nasr-El-Din, H.A., Al-Mohammad, A.M., Al-Shurei, A.A.,
Merwat, N.K., Erbil, M.M., & Samuel, M. (2004b) Matrix stimula-
tion of water disposal Wells using viscoelastic surfactant-based
acid, in SPE Asia Pacific Oil and Gas Conference and Exhibition.
Society of Petroleum Engineers. https://doi.org/10.2118/88588-MS
Nasr-El-Din, H. A., Al-Nakhil, A. R., Al-Driweesh, S. M.,
Welton, T., Sierra, L., & Van Domelen, M. (2009) Application of
cationic surfactant-based fluids for acid diversion. SPE Produc-
tion & Operations, 24:124–134. https://doi.org/10.2118/107687-pa
Nasr-El-Din, H.A., Chesson, J.B., Cawiezel, K.E. & De Vine, C.S.
(2006b) Field success in carbonate acid diversion, utilizing labora-
tory data generated by parallel flow testing, in SPE Annual Techni-
cal Conference and Exhibition. Society of Petroleum Engineers.
https://doi.org/10.2118/102828-MS
Nasr-El-Din, H.A., Taylor, K.C., & Al-Hajji, H.H. (2002) Propagation
of cross-linkers used in in-situ gelled acids in carbonate reservoirs.
Society of Petroleum Engineers (SPE). https://doi.org/10.2118/
75257-ms
Raoul Zana, J.X. (2004) Gemini surfactants: Synthesis, interfacial
and solution-phase behavior. New York, NY. Retrieved from
https://www.routledge.com/Gemini-Surfactants-Synthesis-
Interfacial-and-Solution-Phase-Behavior/Zana-Xia/p/book/
9780824747053
Taylor, D., Kumar, P.S., Fu, D., Jemmali, M., Helou, H., Chang, F.,
Davies, S., & Al-Mutawa, M. (2003) Viscoelastic surfactant based
self-diverting acid for enhanced stimulation in carbonate reservoirs,
in SPE European Formation Damage Conference. Society of
Petroleum Engineers. https://doi.org/10.2118/82263-MS
Wang, Y. J., Zhang, Y. M., Liu, X. L., Wang, J. Y., Wei, L. M., &
Feng, Y. J. (2014) Effect of a hydrophilic head group on Krafft
temperature, surface activities and rheological behaviors of
erucylamidobetaines. Journal of Surfactants and Detergents, 17:
295–230.
Yu, M., Mahmoud, M.A., & Nasr-El-Din, H.A. (2010) Propagation
and retention of viscoelastic surfactants following matrix acidizing
treatments in carbonate cores, in Proceedings—SPE International
Symposium on Formation Damage Control. Society of Petroleum
Engineers (SPE), pp. 786–797. https://doi.org/10.2118/128047-ms
Zhang, W., Mao, J., Yang, X., Zhang, H., Yang, B., Zhang, Z., …
Zhao, Z. (2019) Development of a stimuli-responsive gemini zwit-
terionic viscoelastic surfactant for self-diverting acid. Journal of
Surfactants and Detergents, 22:535–547. https://doi.org/10.1002/
jsde.12267
Hussain, S. M. S., Animashaun, M. A., Kamal, M. S., Ullah, N.,
Hussein, I. A., & Sultan, A. S. (2016) Synthesis, characterization
and surface properties of amidosulfobetaine surfactants bearing
odd-number hydrophobic tail. Journal of Surfactants and Deter-
gents, 19:413–420. https://doi.org/10.1007/s11743-016-1788-9
Kabir, D., & Koya, P. A. (2010) Micellar properties and related ther-
modynamic parameters of the 14-6-14, 2Br− Gemini surfactant in
water + organic solvent mixed media. Journal of Chemical & Engi-
neering Data, 55:1921–1929. https://doi.org/10.1021/je900894x
Kalfayan, L.J. & Martin, A.N. (2009) The art and practice of acid
placement and diversion: History, present state, and future, in SPE
Annual Technical Conference and Exhibition. Society of Petroleum
Engineers. https://doi.org/10.2118/124141-MS
Kamal, M. S. (2016) A review of Gemini surfactants: Potential appli-
cation in enhanced oil recovery. Journal of Surfactants and Deter-
gents, 19:223–236. https://doi.org/10.1007/s11743-015-1776-5
Lynn, J.D. & Nasr-El-Din, H.A. (2001) A core based comparison of
the reaction characteristics of emulsified and in-situ gelled acids in
low permeability, high temperature, gas bearing carbonates, in SPE
International Oilfield Chemistry Symposium Proceedings. Society
J Surfact Deterg (2020)