Study of corrosion and scale inhibition of polyepoxysuccinic acid derivative

Article abstract of DOI:10.14233/ajchem.2014.17659

Polyepoxysuccinic acid derivative was synthesized from L-cysteine and polyepoxysuccinic acid a condensation polymer formed by cyclization and polymerization with maleic anhydride. The structure of polyepoxysuccinic acid derivative was characterized by means of FTIR and ¹³C NMR. The scale inhibition and corrosion inhibition performances of polyepoxysuccinic acid derivative were studied. Scale inhibition and corrosion mechanisms were analyzed by means of SEM. The scale inhibition rate of polyepoxysuccinic acid derivative can reach 98.9 % under Ca²⁺ 400 mg L^-1, HCO₃^- 800 mg L^-1, polyepoxysuccinic acid derivative 8 mg L^-1. Polyepoxysuccinic acid derivative is better than polyepoxysuccinic acid in corrosion inhibition performance and the corrosion inhibition rate can reach 65.14 % at 40 °C in dynamic experiment. SEM showed that the calcium carbonate crystal lattice was distorted completely from calcite to vaterite by using polyepoxysuccinic acid derivative. The surface of the test piece has dense protective adsorption film layer when it was immersed in solution with polyepoxysuccinic acid derivative.

Full text of DOI:10.14233/ajchem.2014.17659

Asian Journal of Chemistry; Vol. 26, No. 22 (2014), 7716-7720
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.17659
Study of Corrosion and Scale Inhibition of Polyepoxysuccinic Acid Derivative
3
2
2
2
XINHUA LIU1,2,*, WENJING WANG , XINJIA TONG , YUNFEI DING , XINQIANG ZHAO and HONG SU
1School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, P.R. China
2Qinggong College, Hebei United University, Tangshan 063000, Hebei, P.R. China
3School of Chemical Engineering and Technology, Hebei United University, Tangshan 063000, Hebei, P.R. China
*Corresponding author: Tel: +86 18633168357; E-mail: hualiyiwang@163.com
Received: 24 March 2014;
Accepted: 27 May 2014;
Published online: 6 November 2014;
AJC-16219
Polyepoxysuccinic acid derivative was synthesized from L-cysteine and polyepoxysuccinic acid a condensation polymer formed by
cyclization and polymerization with maleic anhydride. The structure of polyepoxysuccinic acid derivative was characterized by means of
FTIR and 13C NMR. The scale inhibition and corrosion inhibition performances of polyepoxysuccinic acid derivative were studied. Scale
inhibition and corrosion mechanisms were analyzed by means of SEM. The scale inhibition rate of polyepoxysuccinic acid derivative can
reach 98.9 % under Ca2+ 400 mg L-1, HCO3– 800 mg L-1, polyepoxysuccinic acid derivative 8 mg L-1. Polyepoxysuccinic acid derivative is
better than polyepoxysuccinic acid in corrosion inhibition performance and the corrosion inhibition rate can reach 65.14 % at 40 °C in
dynamic experiment. SEM showed that the calcium carbonate crystal lattice was distorted completely from calcite to vaterite by using
polyepoxysuccinic acid derivative. The surface of the test piece has dense protective adsorption film layer when it was immersed in
solution with polyepoxysuccinic acid derivative.
Keywords: Polyepoxysuccinic acid, Modified polyaspartic acid, Corrosion inhibition, Scale inhibition mechanism.
inhibition. So its application is tremendous limited. In order
to improve the performance of polyepoxysuccinic acid,
modification to polyepoxysuccinic acid is a available method.
Sulfonic acid groups was introduced in molecular structure of
polyepoxysuccinic acid by Zhang et al.10. Scale inhibition
mechanism of polyepoxysuccinic acid and scale inhibition
mechanism of copolymer of polyepoxysuccinic acid and
acrylic acid was studied by Shi et al.11. It has not been reported
that L-cysteine group was introduced in molecular structure
of polyepoxysuccinic acid. In addition to the same amino and
carboxyl groups as all amino acids, L-cysteine has some special
chemical reactions because of sulfydryl, After L-cysteine
molecules react with other compounds, the electronic charge
distribution of N,O,S atoms containing the lone pair electrons
in L-cysteine has changed and caused the change of the
corrosion inhibition performance. In consequence, L-cysteine
group was introduced in molecular structure of polyepoxy-
succinic acid. Polyepoxysuccinic acid derivative with a
side chain L-cysteine was synthesized in this paper and the
performances of the product were studied. The structure of
polyepoxysuccinic acid derivative was characterized by means
of FT-IR and 13C NMR. Calcium carbonate crystals in scale
samples and corrosive test piece were analyzed by means of
SEM.
INTRODUCTION
As the World's environmental protection laws and
regulations, the idea of a green chemistry and green water
treatment agent was deeply rooted in the hearts of people.
People hope to design and synthesize a new biodegradable
water treatment agent with special structure. The United States
developed polyepoxysuccinic acid (PESA) in the early 1990s1
and Japan and other countries have also studied it and its
derivatives2. Polyepoxysuccinic acid is a new biodegradable
water treatment agent without phosphorus and nitrogen with
its scale inhibition, dispersion and become the representative
of a new generation of water treatment agent3-6. Although the
great progress was made to the study of polyepoxysuccinic
acid, the scale inhibition performance is still lower than the
commonly commercially available phosphorous scale inhi-
bitors in high hardness water quality. In order to achieve good
scale inhibition effect, general methods are composed a low
phosphorus formula of better scale inhibition performance with
other agents or directly increase the amount of it7-9. The scree-
ning formula is complex and the compound positions with
phosphorus damage to the environment. The latter increased
the cost and in the case of anti-scaling rate of threshold, even
increasing the dosage of it can not increase the rate of scale

Vol. 26, No. 22 (2014)
Study of Corrosion and Scale Inhibition of Polyepoxysuccinic Acid Derivative 7717
(C1-C0 )
EXPERIMENTAL
η =
×100 %
(1)
(C2 -C0 )
L-cysteine, maleic anhydride and sodium hydroxide were
analytical pure. Epoxy sodium succinate was synthesized from
by cyclizing of maleic anhydride. Polyepoxysuccinic acid was
prepared from epoxy sodium succinate by pyrocondensation.
Polyepoxysuccinic acid derivative was prepared from poly-
epoxysuccinic acid and L-cysteine. The structure of the product
was characterized by FT-IR and 13C NMR spectra. Calcium
carbonate crystals in the scale samples and corrosive test piece
were observed with SEM and the scale corrosion mechanism
of polyepoxysuccinic acid derivative was studied.
where C1 is mass concentration of Ca2+ of heated water sample
with polyepoxysuccinic acid derivative, mg L-1; C0 is mass
concentration of Ca2+ of water sample without polyepoxy-
succinic acid derivative, mg L-1; C2 is mass concentration of
Ca2+ of preparing water sample, mg L-1.
Measurement of the rate of corrosion inhibition: The
aqueous solution of different concentration of corrosion inhi-
bitor was prepared in a beaker. The polishedA3 II carbon steel
slices after weighing is immersed in a solution, put the beaker
in a constant temperature bath and keep the temperature at
40 ºC. and rotated at stated velocity for 72 h.The samples were
washed rapidly with deionized water.After natural drying, the
corrosion samples were wiped off corrosion products, dryed
after cleaning with acetone and weighed with analysis of
weighing scales.The rate of corrosion is calculated by eqn. 2:
Synthesis of epoxy sodium succinate: Epoxy sodium
succinate was synthesized by cyclization of maleic anhydride
at 65 ºC, reacted for 4.5 h.
O
O
O
H2O2 cat.
NaOH
H2O
ONa
ONa
O
NaO2C
CO2Na
8760 × ∆m ×10
NaOH
b =
(2)
A⋅ρ⋅T
O
O
where ∆m is the poor quality of the corrosion samples (g); A
is surface area of the test piece (cm2); ρ is the density of test
piece (g cm-3); T is test time of test piece (h).
Synthesis of polyepoxysuccinic acid: Polyepoxysuccinic
acid was synthesized by pyrocondensation of epoxy sodium
succinate at 85 ºC, reacted for 2 h.
The rate of corrosion inhibition is calculated by eqn. 3:
b0 − b
W =
×100 %
(3)
O
b0
H
C
H
C
where b0 is the rate of corrosion of the test piece without
corrosion inhibitor (mm a-1); b is the rate of corrosion of the
test piece with corrosion inhibitor (mm a-1).
ONa
ONa
Ca(OH)2
O
HO
OH
COONa COONa
n
Preparation of scale sample: The rate of scale inhibition
was detected at 80 ºC. The solution was filtered from the conical
flask after experiment. The scale cling to bottom and wall of
conical flask was dried at the certain temperature, then was
brushed away and conserved in the dryer.
O
Synthesis of polyepoxysuccinic acid derivative: Poly-
epoxysuccinic acid and L-cysteine are put in three bottles and
heated in the methyl silicone oil. The reaction temperature
was 95 ºC and pH was kept at 8-9 for 24 h. The product was
acidified with dilute HCl and then filtrated. The filtrate was
washed with pure ethanol several times. The obtained product
was dried under vacuum at 80 ºC for 6 h. Finally, the pale
yellow of polyepoxysuccinic acid derivative was obtained.
FT-IR: The structure of polyepoxysuccinic acid derivative
was analyzed in 4000-400 cm-1 region with USA PE Spectrum
PX-1.
13C NMR: Using deuterium for water (D2O) as solvent,
polyepoxysuccinic acid derivative was dissolved in 5 mm
nuclear magnetic test tube, then measured carbon spectrum
determination of polyepoxysuccinic acid derivative under
25 ºC.
H
C
H
C
H
O
O
OH
Structural features of calcium carbonate sample: Using
S-250 SEM scanning electron microscope analyze structure
of calcium carbonate sample. The calcium carbonate sample
was stuck on the sample desk with double-sided adhesive,
sprayed gold, then was observed under scanning electron
microscope in the condition of 20 kV acceleration voltage.
NH2
HC COOH
CH2
C
O
C
O
O
H
C
H
C
H
O
O
OH
+
C
C
O
CH2 CH2
OH OH
n
SH
HOOC CH CH COOH
NH2 NH2
n
RESULTS AND DISCUSSION
Rate of scale inhibition performance:A certain concen-
tration of Ca2+, HCO3– and polyepoxysuccinic acid derivative
were injected in deionized water, heated to 80 ºC for 12 h ,
standing, cooling and taking clear liquid. A few drops of
hydrochloric acid was injected, heated and cooled. Mass
concentration of Ca2+ was determined by EDTA method to
assess the scale inhibition performance of scale inhibitors. The
rate of scale inhibition is calculated by eqn. 1:
Fig. 1 showed FT-IR spectra of polyepoxysuccinic acid
derivative and polyepoxysuccinic acid. 3430 cm-1 peak was
the absorption peak of O-H of hydroxide radical and N-H of
amino. 1110.24 cm-1 peak and 1069.79 cm-1 peak were the
absorption peak of -COO- of ester base. 1397.64 cm-1 peak
and 1308.78 cm-1 peak were the absorption peak of -COOH
of the carboxyl and peak has certain strengthen than poly-

7718 Liu et al.
Asian J. Chem.
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
1- PESA
1
2- Lcy-PESA
(a)
2
0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
200 180 160 140 120 100 80 60
40
20
0
ppm
Wavenumbers (cm-1)
Fig. 1. FT-IR polyepoxysuccinic acid derivative and polyepoxysuccinic
acid
epoxysuccinic acid. This absorption peak of polyepoxysuccinic
acid derivative was different from polyepoxysuccinic acid. That
showed polye-poxysuccinic acid derivative prepared from
polyepoxysuccinic acid and L-cysteine.
(b)
Fig. 2 showed 13C NMR spectrum of polyepoxysuccinic
acid derivative and polyepoxysuccinic acid. Fig. 2(a) showed
peak at 170-178 ppm was the absorption peak of carbon of
C=O of carboxy group and 72-82 ppm peak was the absorption
peak of carbon of -CH- of polyepoxysuccinic acid. Fig. 2(b)
showed 171-178 ppm peak was impossible association of
carboxy group and ester base because of a certain difference
between polyepoxysuccinic acid and its derivative. 53-58 ppm
peak was the absorption peak of carbon of C-O-C. 46-47 ppm
and 26-39 ppm peak were the absorption peak of carbon of
-CH-, CH2- and -CH-NH2 from L-cysteine of polyepoxy-
succinic acid derivative. That showed polyepoxysuccinic acid
derivative prepared from polyepoxysuccinic acid and L-
cysteine.
200 180 160 140 120 100 80
60 40
20
0 ppm
Fig. 2. 13C NMR spectrum of (a) PESA and (b) PESA-LCY
TABLE-2
CORROSION INHIBITION RATE IN THE ABSENCE AND
PRESENCE OF POLYEPOXYSUCCINIC ACID AND
POLYEPOXYSUCCINIC ACID DERIVATIVE
Scale inhibition performance: The test of the rate of static
scale inhibition, the scale inhibition performance of polyepoxy-
succinic acid derivative and polyepoxysuccinic acid.was
detected. The test results are showed in Table-1.
Chemical
Dosage
(mg L-1)
Corrosion rate
(mm a-1)
Corrosion inhibition
rate (%)
Blank
PESA
0
0.3615
0.1530
0.1260
-
120
120
57.68
65.14
LCY-PESA
TABLE-1
SCALE INHIBITION RATE IN THE ABSENCE AND
PRESENCE OF POLYEPXYSUCCINIC ACID AND
POLYEPOXYSUCCINIC ACID DERIVATIVE
It was found that polyepoxysuccinic acid derivative is
better than polyepoxysuccinic acid in corrosion inhibition
performance and the corrosion inhibition rate can reach 65.14
%, while the corrosion inhibition rate of polyepoxysuccinic
acid is 57.68 % in dynamic experiment under the temperature
of 40 ºC. Polyepoxysuccinic acid derivative has improved on
the corrosion inhibition. Its application performance was
extended.
Chemical
PESA
Dosage (mg L-1)
Scale inhibition rate (%)
8
8
72.9
98.9
LCY-PESA
Table-1 showed that polyepoxysuccinic acid derivative is
better than polyepoxysuccinic acid, under Ca2+ 400 mg L-1,
HCO3 800 mg L-1 and polyepoxysuccinic acid derivative
composite 8 mg L-1, the scale inhibition rate of polyepoxy-
succinic acid derivative can reach 98.9 %.
–
Results of SEM: Fig. 3(a) showed the most of the calcium
carbonate crystals were calcite without LCY-PESA in the
solution. Fig. 3(b) showed the calcium carbonate crystal lattice
was distorted completely after 1 mg L-1 polyepoxysuccinic
acid derivative was added in the configurating water, which
was vaterite, the calcium carbonate crystal grain obviously
less than the calcium carbonate crystal grain of the configu-
According to the test of the rate of corrosion inhibition
the corrosion inhibition performance of polyepoxysuccinic
acid derivative and polyepoxysuccinic acid was detected.
(Table-2).

Vol. 26, No. 22 (2014)
Study of Corrosion and Scale Inhibition of Polyepoxysuccinic Acid Derivative 7719
Polyepoxysuccinic acid derivative not only can form stable
complex compound and Ca2+ in aqueous solution, reduce the
Ca2+ concentration in the aqueous solution, reduce the possi-
bility of forming such as CaCO3 precipitation, but also make
action with Ca2+ of formed CaCO3 crystal lattice, result to
physical adsorption and chemical adsorption. The electric
double layer was formed on the surface of micro crystal and
there are electrostatic repulsion between micro crystal, hampe-
ring the collision between them and the formation of large
crystals, also hindering collisions and the formation of scale
between micro crystals and the heat transfer surface of metal12.
Surface analysis of corrosive test piece: Fig. 4(a) showed
that there is only some the mechanical scratches before the
test piece was immersed in solution. Fig. 4(b) showed the
(a) SEM photograph of calcium carbonate sample from blank solution
surface has a large number of corrosion products if the test
piece of carbon steel was immersed in blank water. Fig. 4(c)
showed that there is a relatively dense protective adsorption
film layer on surface of the test piece when the test piece of
carbon steel was immersed in solution with polyepoxysuccinic
acid. While Fig. 4(d) showed the surface of the test piece is
very dense protective adsorption film layer if it was immersed
in solution with polyepoxysuccinic acid derivative. This is the
reason why the corrosion inhibition rate of polyepoxysuccinic
acid derivative was higher than polyepoxysuccinic acid.
(b)
SEM photograph of calcium carbonate sample from the solution
with 1 mg L-1 polyepoxysuccinic acid derivative
(a) SEM image of glazed carbon steel surface
(c)
SEM photograph of calcium carbonate sample from the solution
with 2 mg L-1 polyepoxysuccinic acid derivative
Fig. 3. SEM photograph of CaCO3 sample from the solution with modified
polyaspartic acid
rating water. Fig. 3(c) showed the calcium carbonate crystal
lattice was distorted completely when the dosage of polyepoxy-
succinic acid derivative was 2 mg L-1 and then crystal were
finer.
This further illustrated that the scale inhibition rate was
improved due to the presence of calcium carbonate by calcite
crystal shape and structure into the ball aragonite structure.
(b) SEM image of corrosive test piece from blank water

7720 Liu et al.
Asian J. Chem.
conditions, but also associated with molecular structure of
corrosion inhibitor. Polyepoxysuccinic acid derivative not only
contains carboxyl, hydroxyl, etc. polar or non-polar groups as
polyepoxysuccinic acid, but also contains amide group,
sulfydryl, etc. when the metal has empty d-orbitals, a lone
electron pair of O, N, S atoms of these groupsformed coor-
dinate bonds with empty d-orbitals. So the corrosion inhibition
rate of polyepoxysuccinic acid derivative is higher than
polyepoxysuccinic acid through learning more chemical adsor-
ption.
Conclusion
Polyepoxysuccinic acid derivative was synthesized from
L-cysteine and polyepoxysuccinic acid which a condensation
polymer through cyclization and polymerization with maleic
anhydride. The scale inhibition rate of polyepoxysuccinic acid
derivative can reach 98.9 % under Ca2+ 400 mg L-1, HCO3-
800 mg L-1, polyepoxysuccinic acid derivative 8 mg L-1. Poly-
epoxysuccinic acid derivative is better than polyepoxysuccinic
acid in corrosion inhibition performance and the corrosion
inhibition rate can reach 65.14 % under the temperature of
40 ºC in dynamic experiment. The test results of SEM showed
that the calcium carbonate crystal lattice was distorted
completely from calcite to vaterite by using polyepoxysuccinic
acid derivative. The surface of the test piece has dense protec-
tive adsorption film layer when it was immersed in solution
with polyepoxysuccinic acid derivative.
(c) SEM image of corrosive test piece from the solution with
polyepoxysuccinic acid
ACKNOWLEDGEMENTS
This work was supported by the Science Foundation of
Hebei Province, P.R. China (06213027).
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