Open Journal of Applied Sciences, 2012, 2, 93-97
doi:10.4236/ojapps.2012.22012 Published Online June 2012 (
Synthesis and Surface Activity of Cashew-Based
Anion-Nonionic Surfactants
Haiyan Li1, Jun Wang1*, Cha ng h ua n Li u1, Jun Han2, Cuiqin Li1, Mengmeng Ning1
1College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing, China
2Jinzhou Engineering Technology Department of Liaohe Oilfield Company, Jinzhou, China
Email: *
Received April 13, 2012; revised May 14, 2012; accepted May 23, 2012
Four novel anion-nonionic surfactants were synthesized using cashew phenol as raw material. The four structures were
characterized by IR and elemental analysis. Their surface activities were investigated. Their critical micelle concentra-
tions (CMC) are 9.30 × 10–3 mol/L, 8.50 × 10–3 mol/L, 8.10 × 10–3 mol/L and 7.71 × 10–3 mol/L respectively, and the
corresponding surface tensions at CMC are 28.38 mN/m, 28.60 mN/m, 30.40 mN/m and 30.00 mN/m respectively. The
contact angles of the solutions on sheet galsses were measured to observe their surface wettabilities. The effects of their
concentrations, the concentrations of NaCl and temperature on their foaming capacity and foam stability were studied.
Keywords: Cashew Phenol; Anion-Nonionic Surfactant; Surface Activity; CMC
1. Introduction
Anionic surfactants are easy to generate precipitation so
as to lose surface activity in high salinity formation water,
and nonionic surfactants are difficult to dissolve when
temperature exceeds the cloud point. But anion-nonionic
surfactants can overcome the weaknesses of the single
anionic or nonionic surfactants and apply to the reservoir
conditions of high salinity and high temperature [1,2].
Cashew phenol is cheap, green and easy to get in na-
ture, so the surfactants synthesized by cashew phenol
have better ecological performance and accord with the
demand of “green raw materials” of green surfactants.
There are no reports on anion-nonionic surfactants with
cashew phenol as starting material till now.
In the present study, we prepared a series of novel
surfactants-cashew phenol polyoxyethylene-carboxylates
modified anion-nonionic surfactants containing nonionic
and anionic hydrophilic moieties and investigated their
properties. In this paper, we report the surface activities
of theses surfactants, including their surface tension,
wetting and foaming properties, and they exhibit surface
activities similar to those of traditional surfactants [3].
2. Materials and Methods
2.1. Materials
Cashew phenol was supplied by Shanghai Meidong Bio-
logical Material Co., Ltd. in commercial grade. Ethylene
oxide was supplied Liaoyang Petrochemical Company in
commercial grade. Chloroacetic acid, sodium hydroxide,
potassium hydroxide and acetone, purchased from Tian-
jin Damao chemical reagent factory, were of analysis
2.2. Preparation of Cashew Phenol
Polyoxyethylene-Carboxylates Modified
Anion-Nonionic Surfactants
We obtained novel surfactants possessing anion-nonionic
structures through a three-step process (shown in Scheme
1) [4]. In the first step, a series of polyoxyethylene ethers
presenting hydrophilic ethylene oxide chain segments at
phenolic hydroxyl were obtained through ring-opening
polymerizations of cashew phenol with ethylene oxide in
the presence of potassium hydroxide as a catalyst. In the
second step, these polyoxyethylene ethers and chloroace-
tic acid were reacted with sodium hydroxide. The third
step was nucleophilic substitution reaction. The following
description is typical of the procedures used to prepare
the anion-nonionic surfactants: cashew phenol (0.5 mol),
ethylene oxide (4 mol, 5 mol, 6 mol, 7 mol respectively),
and potassium hydroxide (catalyst, 1g) was stirred me-
chanically and heated to 120˚C - 140˚C under the pressure
of 0.25 ± 0.05 MPa. Polyoxyethylene ether (0.02 mol,
13.04 g, 14.8 g, 16.56 g, 18.32 g), chloroacetic acid (3.78 g),
and sodium hydroxide (6.4 g) was stirred magnetically
and heated 30˚C for 1h, and then heated 60˚C for 4.5 h
under the pressure of 5.32 ± 0.05 KPa. The sodium salts
of the products were washed with acetone. Compounds A,
*Corresponding author.
Copyright © 2012 SciRes. OJAppS
B, C and D possess 8, 10, 12 and 14 ethylene oxide units,
respectively (as depicted in Scheme 1).
Step.1: ring-opening polymerization
Step.2: alkalization reaction
Step.3: nucleophilic substitution reaction
Scheme 1. Synthesis of anion-nonionic surfactants A, B, C
and D.
2.3. Analysis
The structures of the final products were confirmed
through infrared (IR) and elemental analysis. IR spectra
recorded in the range 4000 - 600 cm–1 were obtained us-
ing a Japan Spectroscopic FT/IR–3 spectrometer. The ma-
terials were ground with KBr and smeared onto pellets.
Elemental analysis datas were obtained using a Germany
Heraeus Elemental Analyzer.
2.4. Measurements
Surface tensions were determined by Hanging Drop
Method using a JC2002CI surface tensiometer. and the
temperature was maintained precisely at 25˚C. Contact
angles were measured using a JC2002CI intravenous drip
contact angle meter. The foaming properties were deter-
mined using the Ross-Miles method and the temperature
was maintained precisely at 45˚C except the temperature
effect. The foaming capacity was measured in terms of
the height of the foam produced initially; the foam stabil-
ity was measured in terms of the height after 5 min.
3. Results and Discussion
3.1. Preparation of Cashew Phenol
Polyoxyethylene-Carboxylates Modified
Anion-Nonionic Surfactants
The four structures were confirmed through IR and ele-
mental analysis (the results are shown in Table 1). The
IR spectra display bands at 3000-3010 (ph-H),
1210-1275(-O -),110 -1225(-CH 2CH2O-),750-810(p h-H),7
25-780(CH2) [5].
3.2. Surface Tension
Figure 1 shows plots of the surface tensions vs molar
concentrations of anion-nonionic surfactants A, B, C and
D. CMC values of each surfactant given according to the
intersection points of the extension of the straight part of
both sides of turning point in Figure 1 are shown in Ta-
ble 2 [6,7]. An increase in the length of the polyoxye-
thylene chain of the nonionic portion resulted in a de-
crease in the surface activity. This phenomenon is related
to the increased hydrophilicity decreasing the concentra-
tion of the surfactants at the surface [8].
3.3. Wetting Power
Surface tension of water is larger in the common liquid
and it can not be wetting and spreading on the glass sur-
face, after adding surfactant the surface tension of water
Table 1. Elemental analysis of cashew phenol polyoxyethylene-
carboxylates modified anion-nonionic surfactants (F:Found
C: Calculated).
Elemental analysis
C (%) H (%) O (%)
CompoundsUnits of EO
A 8 63.9364.36 8.88 9.33 24.0424.39
B 10 62.3960.15 8.90 8.72 25.3727.69
C 12 62.1160.79 8.92 8.89 26.4328.15
D 14 61.4560.84 8.94 9.02 27.3128.69
Copyright © 2012 SciRes. OJAppS
H. Y. LI ET AL. 95
Figure 1. Surface tensions of A, B, C and D in aqueous so-
lution at 25˚C.
Table 2. CMC values and surface te nsions of anion-nonionic
surfactants at 25˚C.
CMC (mmol/L) 9.30 8.50 8.10 7.71
γCMC (mN/m) 28.38 28.60 30.40 30.00
can significantly reduce, but also may reduce the solid-
liquid interfacial tension, so that it can be spontaneous
re-spread on the glass surface [9]. Usually strong hydro-
philic surfactant has good wetting, and therefore the
contact angle can be measured in aqueous solution of
surfactant on the glass slide to respond to its wettability.
Figure 2 shows the contact angles formed beween
surfactant solutions and glass slide vs concentrations of
the four surfactants. The smaller contact angles observed
for the solutions containing the surfactants, compared
with that of water alone, indicate that these compounds
possess wetting power on the glass slide. With their con-
centrations increased, the contact angles decreased. When
their concentrations exceeded 5000 mg/L, they almost
kept the values and behaved the most effective wet ability.
3.4. Foaming Properties
Tables 3-6 lists the foam properties of four anion-non-
ionic surfactants. Table 3 indicated that with the concen-
trations of the four products increased, the foaming ca-
pacity (measured in terms of the height of foam initially
produced) and foam stability (measured in terms of the
height after 5 min) of them increased. After reaching a
certain degree, they kept the value all long [10-12].
When adsorbing in the gas-liquid interface, the hydration
of the hydrophilic EO chain in molecules makes the hy-
drophilic groups of the surface form the inter-molecular
hydrogen bonding or cross-cut in order to wind each
other so that surface film has a certain strength, so the
products have a foaming ability and foam stability. With
the increase of their concentrations, the concentration of
hydrophilic EO groups increased, the foaming capacity
and foam stability gradually increased, but when the
concentration reached a certain degree, the hydrophobic
of EO chain started to pick up, so foaming capacity and
foam stability were almost no change.
Table 4 indicated that with temperature increased, the
foaming capacity and foam stability decreased. This was
mainly due to the increase of temperature, liquid viscos-
ity and surface viscosity dropped and the foam evapora-
tion rate and inter-bubble gas diffusion rate increased,
and therefore the decay process of foam accelerated, so
the foaming capacity and foam stability decreased.
Figure 2. Contact angles of A, B, C and D in aqueous solution
at 25˚C.
Table 3. The effect of the concentrations of the four surfactants
on their foaming properties.
C/gL–1 3 4 5 6 7 8
H0min/cm10.5 10.6 10.8 11.0 11.3 11.3
H5min/cm8.0 8.3 8.5 9.0 9.0 9.0
H0min/cm12.5 12.8 13.0 13.8 14.0 13.8
H5min/cm11.0 11.5 11.8 12.0 12.0 12.1
H0min/cm13.0 13.3 13.5 13.8 14.0 14.0
H5min/cm12.0 12.3 12.8 12.9 13.0 13.0
H0min/cm12.0 13.8 14.3 14.3 14.3 14.3
H5min/cm10.3 11.8 12.5 12.8 12.5 12.5
Copyright © 2012 SciRes. OJAppS
Table 5 indicated that with the concentrations of NaCl
increased, the foaming capacity and foam stability in-
creased at first and then decreased. This was mainly be-
cause on the one hand, after adding electrolyte, ionic
atmosphere and the thickness of diffuse double layer of
the surfactant ionomers were compressed, and therefore
decreased the repulsion between them, so that surfactant
ions more quickly adsorbed on the surface to form mi-
celles; and with the Na+ concentration increased, more
Na+ into the ionic fog, micelles and adsorption layers, the
formation of the surface micelles speeded up, so that γ,
cmc decreased. In general, the lower γ and the smaller
cmc, the more easily bubble and the more stable foam.
On the other hand, NaCl reached a certain concentration,
diffuse double layer of the membrane was compressed,
and reduced repulsion between the membrane and accel-
erated the discharge fluid process. Therefore, NaCl addi-
tion of a small amount, will help improve the foam per-
formance of the products.
Table 6 indicated that with the concentrations of Ca2+,
Mg2+ increased, the foaming capacity and foam stability
Table 4. The effect of temperature on foaming properties of
the four surfactants.
Temperature/˚C 25 35 45 55 65
A H0min/cm 11 10.7 10.6 10.1 10
5min/cm 8.6 8.5 8.3 7.5 6.4
B H0min/cm 12.8 12.6 12.5 12 11.8
5min/cm 11.3 11.1 11.0 9.8 7.6
C H0min/cm 13.3 13.4 13.0 12 11.1
5min/cm 12.5 12.5 12.0 9.9 8.3
D H0min/cm 14.3 13.9 13.8 13.3 12.7
5min/cm 11.9 11.8 11.3 10.7 8.1
Table 5. The effect of the concentrations of NaCl on foaming
properties of the four surfactants.
W(NaCl)/% 0 0.5 1.0 2.0 3.0 4.0 5.0
A H0min/cm 10.6 11.5 12.312.3 11.9 10.35.9
5min/cm 8.3 9.0 10.09.6 9.5 7.0 3.0
B H0min/cm 12.5 12.5 13.5 13.2 13.0 12.3 12.0
5min/cm 11.0 11.0 11.411.3 11.0 10.39.5
C H0min/cm 13.0 13.5 12.3 11.9 11.9 11.8 11.3
5min/cm 12.0 12.2 8.88.8 8.7 8.57.8
D H0min/cm 13.8 14.0 11.811.5 11.3 10.8 10.6
5min/cm 11.3 11.5 5.55.5 5.5 4.54.3
Table 6. The effect of the concentrations of Ca2+, Mg2+ on
foaming properties of the four surfactants.
w(Ca2+, Mg2+)/10–6 0 0.51.0 2.0 3.0 4.05.0
0min/cm 10.610.610.5 10.4 10.1 9.89.5
5min/cm 8.0 7.9 7.97.8
0min/cm 12.5 12.5 12.3 12.3 12.2 12.0 11.5
5min/cm 9.5 9.5 9.59.0
0min/cm 13.0 12.3 12.2 11.9 11.8 11.6 10.9
5min/cm 12.010.910.7 10.7 10.4 108.8
0min/cm 13.8 12.9 12.5 12.2 11.5 11.2 10.8
5min/cm 11.3 10.7 10.7 10.6 10.5 10.39.3
decreased. This was because, from the molecular struc-
ture -CH2COO- possessed poor resistance to hard water,
when encountering Ca2+, Mg2+, easily generated curd-
like material, and therefore affected the foam properties.
4. Conclusion
We prepared a series of novel cashew phenol polyoxye-
thylene-carboxylates modified anion-nonionic surfactants
through ring-opening polymerization, alkalizetion reac-
tion and nucleophilic substitution reaction. Because of
the unique structural features resulting from the presence
of ethylene oxide and carboxylic hydrophilic groups in a
single molecule, the auxiliaries exhibit good surface ac-
tivities, including low-surface tension, well-foaming and
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