Petroleum Science and Technology, 28:1158–1169, 2010

Copyright © Taylor & Francis Group, LLC

ISSN: 1091-6466 print/1532-2459 online

DOI: 10.1080/10916460902967718

The Preparation and Characterization of Some

Novel Quaternary Iminium Salts Based on

Schiff-base as a Corrosion Inhibitor

M. M. A. EL-SUKKARY,1 I. AIAD,1 A. DEEB,2

M. Y. EL-AWADY,1 H. M. AHMED,1 AND S. M. SHABAN1

1Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt2Faculty of Science, Chemistry Department, Zagazig University,

Zagazig, Egypt

Abstract Novel quaternary iminium compounds, namely, N-(4-methoxybenzylidene)-

N-benzyldodecyliminium chloride (Ia), N-(4-methoxybenzylidene)-N-benzylhexadecyliminium chloride (Ib ), N-(4-methoxybenzylidene)-N-benzyloctadecyliminium chloride

(Ic ), and N-benzylidene-N-benzyldodecyliminium chloride, were prepared. The surfaceproperties such as surface and interfacial tension, foaming, and emulsifying power

of these surfactants were investigated. The surface parameters including criticalmicelle concentration (CMC), maximum surface excess (�max), minimum surface area

(Amin), efficiency (PC20), and effectiveness (�CMC) were calculated. Free energy ofmicellization (�Go

mic) and adsorption (�Goads

) were calculated.

Keywords cationic surfactants, corrosion inhibitors, quaternary iminium salts, sur-face parameters

1. Introduction

Cationic surfactants are of widespread of interest due to their ability to self-assemble

in supermolecular structures such as micelles. The aggregates formed create sharp po-

larity gradients at the interface and define clear hydrophobic regions in an aqueous

solution. Those properties are of fundamental importance for the creation of new materials

(Uhlman, 1991).

Surface activity and micellar properties of surfactants (Alxandridis, 1994; Voicu et al.,

1994; Sugihara et al., 1995; Al-Sabagh, 1998; Burczyk et al., 2001; Chatterjee et al., 2002;

Osman et al., 2003; El-Ghazawy et al., 2004) are of potential importance and scientific

interest. Surfactants micellize in solution after a critical micelle concentration (CMC) de-

pending on their molecular structure and environmental conditions (Clint, 1991; Moulik,

1996). The concept of the CMC value is very useful and perhaps the most frequently

measured and discussed micellar parameter (Lindman and Wennerstrom, 1980). Surface

tension is a widely used physicochemical property at the gas–liquid interface to determine

CMC value without serious difficulty (Adamson, 1990). Through surface tension versus

surfactant concentration curves (SVC), several surface and thermodynamic parameters are

Address correspondence to S. M. Shaban, Egyptian Petroleum Research Institute, Nasr City,11727 Cairo, Egypt. E-mail: samyshaban2010@yahoo.com

1158

Some Novel Quaternary Iminium Salts 1159

derived. Detailed thermodynamics of micellization and adsorption processes are essential

for understanding their stability, spontaneity of formation, and the state of environmental

order or disorder. The corrosion of iron is a fundamental academic and industrial concern

that has received a considerable amount of attention. Quaternary ammonium salts have

been used extensively as inhibitors against the acid corrosion of iron and steel (Kawa

et al., 1996). The action of this class of compounds is commonly attributed to their

adsorption on the surface of the metal. Quaternary ammonium cations are known to be

effective corrosion inhibitors for iron in hydrochloric acid but ineffective in sulfuric acid

(Iofa et al., 1964).

This study aimed to prepare some novel cationic surfactants based on Schiff base

and to determine its surface properties, including CMC, minimum surface area (Amin),

efficiency (PC20), maximum surface excess (�max), and effectiveness (�CMC). Determina-

tion of the foaming power and the corrosion inhibition as well as the biocidal efficiency

of the prepared compounds represent an additional objective of this investigation.

2. Material and Experimental Techniques

2.1. Synthesis

Synthesis of the surfactants compounds was carried out in two steps:

2.1.1. Synthesis of Schiff Base. Different alkyl Schiff bases were synthesized throughout

condensation reactions of different alkyl fatty amines, mainly dodecyl, hexadecyl, and

octadecyl amine with anisaldehyde and benzaldehyde (Erk et al., 2000).

2.1.2. Synthesis of Quaternary Iminium Compounds. To 0.1 mol of Schiff base in

absolute ethanol, 0.1 mol benzyl chloride was added. The reaction mixture was refluxed

for 45 to 90 hr depending on the fatty alkyl chain length of the Schiff base. The solution

was evaporated under reduced pressure. Crystallization from acetone was carried out

three times to obtain the purified quaternary iminium compounds (Ia, Ib, Ic).

2.2. Structural Confirmations of the Prepared Compounds

The chemical structure of the synthesized compounds was characterized by:

1. Fourier transform infrared (FTIR) spectra using ATI Mattson Infinity seriesTM Bench-

top 961 controlled by Win FirstTM V2.01 software (Egyptian Petroleum Research

Institute Cairo, Nasr City, Egypt).

2. 1HNMR was measured in DMSO-d6 by Spect Varian, GEMINI 200 (1H 200 MHz).

(Micro Analytical Center, Cairo University, Cairo, Egypt).

2.3. Experimental Techniques

2.3.1. Surface and Interfacial Tension. Surface and interfacial tension of the prepared

compounds solutions were measured using a Du-Nouy tensiometer (Kruss type 8451).

The surface tension of different concentrations at different temperatures (15ıC, 35ıC,

45ıC) was measured.

1160 M. M. A. El-SukKary et al.

2.3.2. Surface Parameters of the Prepared Compounds

1. Critical micelle concentration: The values of the CMC of the prepared compounds

were determined using surface tension techniques. In this method, the surface tension

values were plotted against the corresponding concentrations. The interrupt change in

the surface tension concentration (SC) curves express on the CMCs.

2. Effectiveness: �CMC is the difference between the surface tension of the pure water

( o) and the surface tension of the surfactant solution ( ) at the critical micelle

concentration.

�CMC D o �

3. Maximum surface excess: The values of �max were calculated from surface or inter-

facial data by the use of the Gibbs equation (Shuichi et al., 1991).

�max D �1=2:303 RT.ı =ı log c/T

where �max is maximum surface excess in mol/cm2; R is universal gas constant 8.31 �

107 ergs mol�1 K�1; T is absolute temperature (273.2 CıC); ı is surface pressure

in dyne/cm; C is surfactant concentration; and (ı =ı log c)T is the slope of a plot of

surface tension vs. concentration curves below CMC at constant temperature.

4. Minimum surface area: The area per molecule at the interface provides information

on the degree of packing and the orientation of the adsorbed surfactant molecule.

The average area (in square angstroms) occupied by each molecule adsorbed on the

interface (Takeshita and Wakebe, 1982) is given by:

Amin D 1016=�max N

where �max is maximum surface excess in mol/cm2 and N is Avogadro’s number,

6.023 � 1023.

5. Thermodynamic parameters of micellization and adsorption: The thermodynamic pa-

rameters of adsorption and micellization of the synthesized cationic surfactants were

calculated according to Gibb’s adsorption equations as follows (Rosen, 1987):

�GOmic D RT ln.CMC/

�GOads D �GO

mic � 6:023 � 10�2� �CMC � Amin

�Smic D �d.�GOmic=�T/

�Sads D �d.�GOads=�T/

�Hmic D �GOmic C T�Smic

�Hads D �GOads C T�Sads

2.3.3. Corrosion Inhibition of the Prepared Compounds. A weight loss technique was

used to measure the corrosion inhibiting effect of the prepared quaternary compounds

for mild steel specimen having a composition as follows (wt%): 0.21 C, 0.035 Si, 0.51

Mn, 0.82 P, and the remainder Fe. Each specimen was sequentially machined into regular

shapes of 54.006 cm2 cross-sectional area. The specimens were sequentially abraded with

different emery papers, degreased with acetone, washed with distilled water, and then

Some Novel Quaternary Iminium Salts 1161

dried. Corrosive solutions of 1 M HCl in the absence and presence of the inhibitors at

concentrations between 1 � 10�5 and 1 � 10�3 M prepared from doubly distilled water

were used.

The inhibition efficiency (E%) of an inhibitor was calculated from the following

equation:

E% D .CR � CR0/=CR � 100

CR D KW=ATD

where CR and CR0 are the corrosion rate of the carbon steel in the absence and presence

of an inhibitor at given inhibitor concentration and temperature, W is the weight loss (g),

A is surface area of the mild steel species (cm�2), D is density of the species (g/cm3)

and is equal 7.88 g/cm3, K is a constant (3.45 � 106), and T is immersion time (hr).

3. Results and Discussion

3.1. Chemical Structure

The chemical structure of the prepared cationic surfactants was confirmed by the FTIR

and 1HNMR spectra.

3.1.1. FTIR Spectra. FTIR spectroscopy was used to identify the functional groups of

prepared cationic surfactants. The FTIR spectra of compound Ia is shown in Figure 1,

which shows the stretching vibration band of �C�H aliphatic symmetric and asymmet-

ric at 2,844 and 2,913 cm�1 , respectively; DC�H aromatic stretching at 3,004 cm�1 ;

�NDCH� stretching at 1,620 cm�1 ; CDC aromatic stretching at 1,509 cm�1 ; �CH2

bending at 1,463 cm�1 ; and C�O stretching at 1,091 cm�1. We observe the disappearance

of two absorption bands of CDO and �NH2 at 1,725 and 3,300 cm�1, respectively.

3.1.2. 1HNMR Spectra. The 1H-NMR spectra data (ı ppm) of the compound (Ia) are

shown in Figure 2, which shows that ı D 0.84–0.872 (t, 3H, �CH3); ı D 1.261 (m,

18 H, �(CH2)9CH3); ı D 1.571 (m, 2H, �CH2CH2N˚); ı D 2.527 (S, 2H, �CH2ph);

Figure 1. 1H-NMR spectra of N-(4-methoxybenzylidene)-N-benzyldecyliminium chloride (Ia).

1162 M. M. A. El-SukKary et al.

Figure 2. General chemical structure of prepared compounds.

ı D 2.7–2.773 (t, 2H, �CH2CH2N˚); ı D 3.381 (S, 3H, �OCH3); ı D 7.414 (5H,

�CH2-ph); ı D 7.599 (4H, ph-OCH3); ı D 8.176 (S, 1H, ˚N D CH-ph).

The data obtained from FTIR and 1HNMR spectra showed that the synthesized

inhibitors are as represented in Figure 3.

3.2. Surface Properties

3.2.1. Surface and Interfacial Tension. Surface tension values were measured for aque-

ous solutions of the prepared cationic surfactant with different concentrations at differ-

ent temperatures (15ıC, 35ıC, 45ıC) and the data are represented in surface tension–

concentration curves as shown in Figures 4 and 5. It is clear that surface tension

decreases with increasing concentration and increasing length of the hydrophobic chain

and temperature at constant concentration. This can be explained due to the adsorption

of surfactant molecules at the surface. When materials that contain a hydrophilic and

hydrophobic group attached together in the same molecule are dissolved in a solvent, the

structure of the solvent is distorted and therefore increases free energy of the system;

thus, molecules concentrate at the interface in a way that minimizes the free energy of

the system, where the hydrophobic part is oriented away from the solvent to avoid

energetically unfavorable contact with aqueous media, and the hydrophilic group is

directed toward the bulk; this adsorption at the interface provides an expanding force

Some Novel Quaternary Iminium Salts 1163

Figure 3. FTIR spectra of N-(4-methoxybenzylidene)-N-benzyldecyliminium chloride (Ia).

Figure 4. Surface tension values of Ia at different concentrations and temperatures.

Figure 5. Surface tension values of Ib at different concentrations and temperatures.

1164 M. M. A. El-SukKary et al.

acting against the normal surface tension, and thus surface tension is decreased (Rosen,

1989). So by increasing the concentration of surfactant, the adsorption at the interface

will increase, so surface tension decreases until a stable lower level is achieved. This

lower level of surface tension corresponds to maximum monolayer-level adsorption at

the air–water interface. Further increasing surfactant concentration above this maximum

interfacial adsorption level leads to formation of surfactant aggregation known as micelle

in solution. For example, the surface tension of Ia at concentration of 5 � 10�4 is

51.5 mN m�1 and at 5 � 10�3 is 27 mN m�1 at 15ıC.

Also, by increasing the length of the hydrophobic chain, the surface tension decreases

as a result of increasing of hydrophobicity, thus increasing the free energy of adsorption

so more reduction in surface tension. For example, the surface tension of compound Ia

is 51.5, whereas Ib is 43.7 mN m�1 at a concentration of 5 � 10�4 and at 15ıC.

Also, there is a decrease in surface tension by rising temperature as shown in

Figures 4 and 5, due to rising temperature causes disruption of the structured water

surrounding the hydrophobic group, an effect that disfavors micellization. For example,

the surface tension of compound Ia at concentration of 5 � 10�4 is 51.5, 43.7, and 42

mN m�1 at 15ıC, 35ıC, and 45ıC, respectively.

3.2.2. The Critical Micelle Concentration. Critical micelle concentration values of the

prepared cationic surfactant were determined by plotting the surface tension ( ) of

surfactant solutions versus their bulk concentrations in mol/L at 15ıC, 35ıC and 45ıC.

The CMC values listed in Table 1 show a decrease with increase in temperature and

the length of the hydrophobic chains. The rise of temperature probably decreases in the

hydration of the hydrophilic group, which favors micellization. On the other hand, the

rise of temperature causes disruption of the structured water surrounding the hydrophobic

group, an effect that disfavors micellization. The relative magnitude of these two opposing

effects determines whether the CMC increase or decrease over a particular temperature

range. The data in Table 1 reveal that with a decrease in CMC with rising temperature,

micellization is enhanced.

The increase of the hydrophobic chain length decreases the solubility and conse-

quently increases the free energy of the system, leading to concentration of surfactant

molecules at the surface. Also, aggregation of surfactant molecules into micelles with

their hydrophilic part directed to the solvent and the hydrophobic parts directed to the

interior of the micelle.

3.2.3. Maximum Surface Excess (�max). The values of �max are represented in Table 1.

When increasing the temperature and hydrophobic moiety length of the prepared surfac-

Table 1

Surface properties of the synthesized cationic surfactants at different temperatures

CMC � 10�4,

mol � L�1…cmc , mN m�1

�max � 10�10,

mol � cm�2Amin , nm2

Comp. 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC

Ia 59.5 25.7 24.95 49.4 41.2 39.7 4.55 3.038 2.502 0.36 0.546 0.66

Ib 20.96 6.88 3.36 40.2 41.2 38.2 2.253 2.025 1.513 0.736 0.82 1.097

Ic 0.18 0.12 0.0367 31.8 35.3 34 1.658 1.348 0.703 1.00 1.23 2.36

Some Novel Quaternary Iminium Salts 1165

Table 2

The thermodynamic parameters of micellization of the prepared cationic surfactants

�Gmic, kJ mol�1

�S D ��G/T,

kJ mol�1 K�1 �HMIC, kJ mol�1

Comp. 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC

Ia �12.27 �15.28 �15.85 0.1236 0.1236 0.1236 23.34 22.81 23.48

Ib �14.77 �18.65 �21.15 0.21 0.21 0.21 45.74 46.07 45.67

Ic �26.19 �29 �33.09 0.217 0.217 0.217 36.36 37.9 35.98

tants, �max shifts to lower concentrations and thus the surfactant molecules are directed

to the interface, which decreases the surface energy of their solutions.

3.2.4. Minimum Surface Area (Amin). The minimum area per molecule at the aqueous

solution/air interface for the prepared surfactants is listed in Table 1. When Amin increases

with increasing length of hydrophobic moiety and temperature due to decreasing �max,

the distances between molecules are increased, so Amin increased.

3.2.5. Effectiveness (˘CMC). Efficiency values of the prepared cationic surfactants are

given in Table 1. From these data it was observed that increasing the alkyl chain length

and temperature decreases the efficiency. This is because the efficiency of adsorption at

the interface increases linearly with an increase in the carbon atoms in the hydrophobic

group and temperature as illustrated in the discussion on surface tension (Rosen, 1987).

The values of effectiveness are listed in the Table 1. It is clear that …CMC decreases

by increasing the hydrophobic chain; for example, …CMC of Ia, Ib, and Ic are 49.4, 40.2,

and 31.8, respectively.

3.2.6. Standard Free Energies of Micellization and Adsorption (�Gomic; �Go

ads). The

thermodynamic parameters of micellization and adsorption are summarized in Tables 2

and 3, respectively, where theses parameters are calculated at 15ıC, 35ıC, and 45ıC.

From thermodynamic parameter of micellization it was observed that the �GOmic are

negative and point to micellization as a spontaneous process.

Also �GOmic increase in the negative direction by increasing both temperature and

length of hydrophobic moiety, which implies that by increasing temperature from 15ıC

Table 3

Thermodynamic parameter of adsorption of the prepared cationic surfactants

�Gads, kJ mol�1

�Sads D ��G/T,

kJ mol�1 K�1 �Hads, kJ mol�1

Comp. 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC 15ıC 35ıC 45ıC

Ia �13.36 �16.63 �17.43 0.1399 0.1399 0.1399 26.95 26.47 27.077

Ib �16.55 �20.68 �23.67 0.233 0.233 0.233 50.59 51.12 50.463

Ic �28.11 �31.61 �37.930 0.3055 0.3055 0.3055 59.93 62.53 59.27

1166 M. M. A. El-SukKary et al.

to 45ıC and the length of hydrophobic moiety, the hydrophobicity increasees, and thus

free energy of the system will increase so molecules tend to form micelles in a way

that minimizes free energy so the change in the free energy of the system as a result of

micelle formation will increase.

Also, we can observe that �Smic is positive and it increases by increasing the

hydrophobic chain length, which is an indication that by increasing the hydrophobic

chain length, there is an increase in the randomness in the system upon transformation of

surfactant molecules into micelles in another means the compounds favor micellization

by increasing hydrophobic character, and thus CMC is decreased.

From the thermodynamic parameter of adsorption it was observed that standard

free energy of adsorption (�GOads) is negative and points to adsorption as a spontaneous

process. Also, �GOads increases in the negative direction by increasing both temperature

and length of hydrophobic moiety, which implies that by increasing temperature from

15ıC to 45ıC and the length of hydrophobic moiety, the compounds favor adsorption

at the interface (adsorption at the interface lower surface and interfacial tension that by

expanding force acting against the contracting force resulting from surface and interfacial

tension) where the hydrophobic part directed away from solvent in a way that minimizes

free energy of the system, and thus the change in free energy as a result of the adsorption

process will increase.

It can be observed that �Sads is positive and increases by increasing the hydrophobic

chain length.

In comparing the thermodynamic parameter of micellization and adsorption we

observed that �GOads is more negative direction �GO

mic, indicating the tendency of the

molecules to be adsorbed at the interface and the adsorption process at the interface is

associated with a decrease in the free energy of the system.

3.3. Corrosion Inhibition of the Prepared Compounds

The efficiency values of the prepared cationic surfactant corrosion inhibitors are shown

in Table 4. We found that by increasing the concentration of the surfactant, the inhibition

efficiency increased as a result of increased adsorption at the interface (solid–liquid

interface). The surfactants adsorb on the metal surface through heteroatoms such as

nitrogen, oxygen, or sulfur and multiple bonds or aromatic rings that block the active

sites of local galvanic cell, which decreases the corrosion rate of the metal (Ramesh and

Rajeswari, 2002).

Table 4

Inhibition efficiency of different concentrationsa

Efficiency

Comp.

1 �

10�5 M

5 �

10�5 M

7 �

10�5 M

1 �

10�4 M

5 �

10�4 M

1 �

10�3 M

Ia 28.92 89.96 91.9 98.38 98.07 98.6

Ib 38.61 90.3 94.18 97.16 97.18 97.23

Ic 40.146 92 95.55 97.37 97.52 97.47

aThe corrosion rate of the control sample is 342.8 mpy.

Some Novel Quaternary Iminium Salts 1167

Corrosion inhibitors such as cationic compounds are charged surfactants, and when

adsorbed on a metal surface, only a monolayer of its molecules is possible because the

positive charge-containing molecules would repel each other. Therefore, the adsorption

of the prepared compounds can be expected to follow a Langmuir isotherm.

The efficiency of the compound Ia at concentration of 1 � 10�5 M is 25.9% and at

a concentration of 1 � 10�3 is 98.6%.

By increasing the hydrophobic chain length, the inhibition efficiency increases before

the CMC values of the compounds, which is due to increasing the adsorption of the

surfactants on the iron surfaces, which protects it from the corrosive ions and increases

its resistance; however, after the CMC not increases this may be due to formation

monolayer on the metal surface. The inhibition efficiency of compounds Ia, Ib, and Ic at a

concentration of 7 � 10�5 are 91.9, 94.2, and 95.5, respectively. The maximum efficiency

of these molecules may be around the CMC. The increase in inhibitor concentrations may

not enhance the efficiency of these compounds.

3.3.1. Thermodynamic Parameters of Adsorption Process. The adsorption of the in-

hibitor depends on its chemical structure, the type of metal and the nature of its surface,

the nature of the corrosion medium (its pH value), temperature, and the electrochemical

potential of the metal–solution interface.

Adsorption provides information about the interaction among the adsorbed molecules

themselves as well as their interaction with the electron surface. The mathematical

relationship for the adsorption isotherms suggests fitting the experimental data of the

present work to a Langmuir equation (Langmuir, 1918):

�=1 � � D KŒI�

where K is the equilibrium constant of the adsorption reaction, [I] is the inhibitor

concentration in the bulk of the solution, and � is the surface coverage.

The surface coverage, � , is the fraction of the surface covered by the inhibitor

molecules. It is calculated from the following equation:

� D 1 � W 0=W

where W 0 and W are the corrosion rates in the presence and absence of the inhibitor,

respectively.

Figure 6 shows a plot of (� /1 � �) vs. [I] (Langmuir adsorption plots) for adsorption

of dodecyltriethyliminium bromide on the surface of the carbon steel sample in 1 M HCl

solution.

The above relations are straight lines, which indicates that the Langmuir isotherm

is valid for this system. Langmuir’s isotherm is applied for an ideal case of physical

and chemical adsorption on a smooth surface with no interaction between the adsorbed

molecules.

3.3.2. Relation between the Surface Properties and Corrosion Inhibition. The data

listed in Table 1 reveal that the maximum effective concentrations of the inhibitors range

from 1 � 10�4 to 7 � 10�5 M; i.e., around the CMC. The greatest reduction of surface

tension (effectiveness, …CMC) was achieved by Ia compared with that obtained by the

other two compounds. This is in good agreement with the inhibition efficiency result

achieved by Ia (Tables 1–4).

1168 M. M. A. El-SukKary et al.

Figure 6. Relation between (� /1 � � ) and inhibitor concentrations in 1 M HCl.

It seems that the investigated surfactants favor adsorption rather than micellization.

The fact that �Gads is more negative compared with the corresponding �Gmic may be

taken as strong evidence for the greater feasibility of the adsorption of the investigated

surfactants. It remains now to point out that �max of the prepared compounds is decreased

with an increase in the alkyl chain length; on the other hand, Amin is increased. �max of Ia

is higher, which indicates that a greater number of molecules are adsorbed. This implies

close packing of the adsorbed molecules associated with less area on the metal surface

for each molecule, thus leading to more electrostatic interaction well packed adsorbed

layer and more homogenous adsorbed film. All these parameters explain why Ia is the

most effective corrosion inhibitor.

4. Conclusions

From the obtained results we can conclude that:

1. All the prepared compounds have good surfactant properties.

2. The prepared cationic surfactants show good inhibition properties for the corrosion

of low carbon steel in 1 M HCl solution at room temperature, and the inhibition

efficiency increases with increasing concentration of the inhibitors until it reaches a

maximum value near the critical micelle concentration.

3. The corrosion inhibition of the prepared compounds increases with an increase in the

alkyl chain length.

References

Adamson, A. W. (1990). Phys. Chem. Surf. 5th ed. New York: Interscience.

Alexandridis, P., Holzwarth, J. F., and Hatton, T. A. (1994). Micellization of poly (ethylene oxide)-

Poly (propylene oxide)-Poly (ethylene oxide) triblock copolymers in aqueous solutions: Ther-

modynamics of copolymer association. New York: Interscience. Macromolecules 27:2414–

2425.

Al-Sabagh, A. M. (1998). Surface activity and thermodynamic properties of water-soluble polyester

surfactants based on 1,3-dicarboxymethoxybenzene used for enhanced oil recovery. Colloid.

Surface. Physicochem. Eng. Aspect. 134:313–320.

Some Novel Quaternary Iminium Salts 1169

Burczyk, B. K., Wilk, A., Sokolowski, A., and Syper, L. J. (2001). Synthesis and surface Properties

of N-Alkyl-N-methylgluconamides and N-Alkyl-N-methyllactobionamides. Colloid Interface

Sci. 240:552–558.

Chatterjee, A., Maiti, S., Sanyal, S. K., and Moulik, S. P. (2002). Micellization and related behaviors

of n-cetyl-n-ethanolyl-n,n-dimethyl and n-cetyl-n,n-diethanolyl-n-methyl ammonium bromide.

Langmuir 18:2998–3004.

Clint, J. H. (1991). Surfactant Aggregation. New York: Chapman and Hall.

El-Ghazawy, R. A., Abdel Raheem, R., and Al-Sabagh, A. M. (2004). Surface activity: thermo-

dynamic properties and light scattering studies for some novel aliphatic polyester surfactants.

Polymer Adv. Tech. 15:244–250.

Erk, B., Dilmac, A., Baran, Y., and Balaban, A. (2000). Characterization and kinetics of formation

of some Schiff base chelates of Sn(II) and UO2(V1). Synth. React. Inorg. Met. Org. Chem.

10:30–37.

Iofa, Z. A., Batrakov, V. V., and Ba, C.-N. (1964). Influence of anion adsorption on the action of

inhibitors on the acid corrosion of iron and cobalt. Electrochim. Acta 9:1645–1653.

Kawa, T., Nishihara, H., and Aramaki, K. (1996). Corrosion Sci. 38:225.

Langmuir, L. (1918). The adsorption of gases on plane surfaces of glass, mica and platinum. J. Am.

Chem. Soc. 40:1361–1403.

Lindman, B., and Wennerstrom, H. (1980). Miceles. Amphiphile aggregation in aqueous solution.

Top. Curr. Chem. 87:1–87.

Moulik, S. P. (1996). Micelles: self-organized surfactant assemblies. Curr. Sci. 71:368–376.

Osman, M. M., El-Ghazawy, R. A., and Al-Sabagh, A. M. (2003). Corrosion inhibitor of some

surfactants derived from maleic–oleic acid adduct on mild steel in 1 M H2SO4. Mat. Chem.

Phys. 80:55–62.

Ramesh, S., and Rajeswari, S. (2002). Corrosion inhibition of mild steel by Schiff base compounds

in various aqeous solutions Paper No. 6., Proceedings of International Congress on Emerging

Corrosion Control Strategies for the New Millennium (GLOCORR-2002) New Delhi, India,

February 20–22.

Rosen, M. J. (1987). Surfactants and Interfacial Phenomena. New York: Wiley.

Rosen, M. J. (1989). Surface and Interfacial Phenomena, 2nd ed. New York: John Wiley & Sons.

Shuichi, M., Kazayasu, I., Sadao, Y., Kazuo, K., and Tsuyoshi, Y. (1991). Surface activities,

biodegradability and antimicrobial properties of glucosamine derivatives containing alkyl

chains. J. Am. Oil Chem. Soc. 67:996–1001.

Sugihara, G., Arakawa, Y., Tanaka, K., Lee, S., and Moroi, Y. (1995). J. Colloid Interface Sci.

170:399.

Takeshita, T. I., and Wakebe, M. S. (1982). Synthesis of EDTA monoalkyl amide chelates and

evaluation of the surface-active properties. J. Am. Oil Chem. Soc. 59:90.

Uhlman, A. (1991). An Introduction to Ultrathin Organic Films. San Diego: Academic.

Voicu, A., Elian, M., Balcan, M., and Anghe, D. F. (1994). Synthesis and micellar properties of

some homogeneously ethoxylated nonlyphenols. Tenside Surfactants Detergents 31:120–123.