Using chiral ionic liquid additives to enhance asymmetric induction in a Diels-Alder reaction

Article abstract of DOI:10.1039/c6dt04572c

A bis-oxazoline ligand has been complexed using Cu(ii) and Zn(ii) trifluoromethanesulfonate and a range of chiral ionic liquid (CIL) additives based on natural products were used as a co-catalyst for a Diels-Alder reaction. The catalytic performance of th

Full text of DOI:10.1039/c6dt04572c

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: P. Goodrich, N.
Gunaratne, L. Hall, Y. Wang, L. Jin, M. J. Muldoon, A. Ribeiro, A. J. L. Pombeiro, V. Parvulescu, P. Davey
and C. Hardacre, Dalton Trans., 2016, DOI: 10.1039/C6DT04572C.
This is an Accepted Manuscript, which has been through the
Volume 45 Number
1 7 January 2016 Pages 1–398
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
Accepted Manuscripts are published online shortly after
An international journal of inorganic chemistry
www.rsc.org/dalton
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

Page 1 of 33
Dalton Transactions
View Article Online
DOI: 10.1039/C6DT04572C
Enhancement of corrosion protection performance of epoxy
coating by introducing new hydrogenphosphate compound
Journal: Dalton Transactions
Manuscript ID DT-ART-12-2016-004752
Article Type: Paper
Date Submitted by the Author: 16-Dec-2016
Complete List of Authors: Deyab, M; Egyptian petroleum research institute, , Analysis and Evaluation
Dep.
Ouarsal, Rachid ; Université Sidi Mohamed Ben Abdellah
Al-Sabagh, A ; Egyptian Petroleum Research Institute
Lachkar, Mohammed ; Université Sidi Mohamed Ben Abdellah
El Bali, B. ; Université Sidi Mohamed Ben Abdellah

Page 1 of 32
Dalton Transactions
Page 2 of 33
Guidelines to
View Article Online
DOI: 10.1039/C6DT04572C
Referees
Communications & Papers
The international journal for inorganic, organometallic and bioinorganic chemistry
http://www.rsc.org/dalton
Dalton Transactions wishes to encourage high quality articles
reporting exciting new developments in inorganic chemistry.
For an article to be accepted, it must report new, high-quality
research and make a significant contribution to the field.
Manuscripts that describe purely physical, crystallographic or
computational studies must include the clear relevance of the
work to the broad inorganic chemistry readership of Dalton
Transactions.
Communications must report chemistry of sufficient importance
and impact to justify preliminary publication. Papers should
report more complete studies.
Dalton Transactions’ Impact Factor is 4.19 (2014 Journal Citation Reports®)
Routine or unnecessarily fragmented work, however competently researched and
reported, should not be recommended for publication.
Thank you very much for your assistance in evaluating this manuscript
Dr Andrew Shore (dalton@rsc.org)
Royal Society of Chemistry
Editor, Dalton Transactions
Professor John Arnold
University of California, Berkeley
Chair, Dalton Transactions Editorial Board
General Guidance (for further details, see the RSC Refereeing Procedure and Policy)
When preparing your report, please:
 Comment on the originality, importance, impact and scientific reliability of the work
 State clearly whether you would like to see the paper accepted or rejected and give detailed
comments (with references, as appropriate) that will help both the Editor to make a decision on
the paper and the authors to improve it
Please inform the Editor if:
 There is a conflict of interest
 There is a significant part of the work which you are not able to referee with confidence
 If the work, or a significant part of the work, has previously been published, including online
publication (e.g. on a preprint server/open access server)
 You believe the work, or a significant part of the work, is currently submitted elsewhere
 The work represents part of an unduly fragmented investigation

Page 3 of 33
Dalton Transactions
Page 2 of 32
Letter to Referees
Dalton Transactions embraces all aspects of the chemistry of inorganic
and organometallic compounds.
Anticorrosive coating is highly important, because corrosion reduces the
strength of structural materials and this destruction involves direct and
indirect losses including problems related to human safety and facts
concerning natural resources conservation.
View Article Online
DOI: 10.1039/C6DT04572C
Inorganic compounds are an integral part of anticorrosion paints. At
present, close attention is paid especially to the research and development
of non-toxic anticorrosive materials that can replace pigments based on
lead and chromium.
The synthesis of transition metal phosphates compounds with open-
framework structures has been extensively studied due to their
applications in adsorption, catalysis, electronics, ionic conduction, ion-
exchange processes, magnetism and separation.
In this work, studies have been made in order to introduce new generation
of epoxy coatings mostly based on new hydrogenphosphate compounds
(NH4)2[Mg(H2O)6]3(HPO3)4.
Regarding to the topics specifically covered in Dalton Transactions, we
would like to submit our work for publication in Dalton Transactions
journal
We declare that Full papers contain original scientific work that has not
been published previously.

Page 3 of 32
Dalton Transactions
Page 4 of 33
View Article Online
DOI: 10.1039/C6DT04572C
Enhancement of corrosion protection performance of epoxy coating
by introducing new hydrogenphosphate compound
M. A. Deyab1*, Rachid Ouarsal2, A. M. Al-Sabagh1 , Mohammed
Lachkar2, B. El Bali2
1Egyptian Petroleum Research Institute (EPRI), PO Box 11727, Nasr
City, Cairo, Egypt
2Laboratoire d’Ingénierie des Matériaux Organométalliques et
Moléculaires, Unité Associée au CNRST (URAC 19), Faculté des
Sciences, Université Sidi Mohamed Ben Abdellah, B.P.1796 (Atlas),
30000 Fès, Morocco.
* Corresponding author. Tel.: +201006137150; fax: + 202 22747433 Eꢀ
mail address: hamadadeiab@yahoo.com
Abstract
(NH4)2[Mg(H2O)6]3(HPO3)4 (MgHP) was synthesized by a wet chemistry
route and characterized by IR spectroscopy. The influence of MgHP on
the antiꢀcorrosion and mechanical properties of epoxy coating were
investigated using electrochemical impedance spectroscopy (EIS), nanoꢀ
indentation and scanning electron microscopy (SEM) techniques as well
as the water uptake measurements. Results showed that the incorporation
of MgHP particles increased antiꢀcorrosion and mechanical properties of
epoxy coating. The epoxy coating performance enhances with increasing
1

Page 5 of 33
Dalton Transactions
Page 4 of 32
View Article Online
DOI: 10.1039/C6DT04572C
concentration of MgHP particles up 1.0%. It was observed that the
volume of water uptake by epoxy coating reduced after modification with
MgHP particles as compared to neat epoxy coating
.
Keyword: epoxy coating; Corrosion resistance; hydrogenphosphate;
electrochemical; carbon steel
1. Introduction
The synthesis of transition metal phosphates compounds with openꢀ
framework structures has been extensively studied due to their
applications in adsorption, catalysis, electronics, ionic conduction, ionꢀ
exchange processes, magnetism and separation [1ꢀ5].
Replacement of [PO4]ꢀphosphate by [HPO3/H2PO3]ꢀphosphite groups
allowed the preparation of a new class of metal phosphite compounds,
where phosphorus at its low oxidation state (+3), with original structural
frameworks, varying from 0ꢀD cluster to 3ꢀD openꢀframework structures
are obtained [6ꢀ13]. Generally, a transition metal phosphite is synthesized
mainly by a direct reaction between H3PO3 and the metals ions [14, 15].
However, few simple phosphite compounds containing either Mg+2, and
mixed contain also an alkali/ammonium cations are known:
MgHPO3(H2O)6 [16], NaMg(H2PO3)3.(H2O)[17] and the title compound
(NH4)2[Mg(H2O)6]3(HPO3)4 which have been twice reported [18, 19].
Carbon steel has been widely employed as construction materials for
pipe work in the oil and gas production [20ꢀ21].
2

Page 5 of 32
Dalton Transactions
Page 6 of 33
View Article Online
DOI: 10.1039/C6DT04572C
The efficiency of cathodic protection (CP) method on carbon steel
pipelines can be improved by organic coatings [22ꢀ23].
Barrier coatings can be used alone or in combination with impressed
current driven cathodic protection systems, where they act to minimize
exposed cathode areas and thereby reduce the cost of required electricity
that maintains the direction of current flow [24]
Increasing cathodic protection is often considered as the best or only
solution to prevent corrosion on a pipeline with poor or disbonded
coatings [25]. The CP may help to protect pipelines exposed to the
electrolyte, but it does not always protect the pipe under many types of
disbonded coatings, therefore corrosion will continue unless these
coatings are replaced [26].
Organic coatings can protect metal substrates from corrosion via two
mechanisms. The first one is the electrochemical mechanism where it
inhibits the corrosive reactions by sharing an anticorrosive pigment in the
passivation of the metal, forming stable and strongly adhesive layers on
the substrate. The second mechanism is the barrier mechanism. Where it
depends on the inhibiting the access of corrosive environmental agents to
the metal surface [27ꢀ29].
Organic coating film has limited lifetime and finally decays, allowing
corrosive ions to contact with the substrate. The barrier performance of
coatings can be enhanced by the incorporation of inorganic filler particles
3

Page 7 of 33
Dalton Transactions
Page 6 of 32
View Article Online
DOI: 10.1039/C6DT04572C
[29ꢀ33]. This particles increase the coating performance by decreasing the
porosity and zigzagging the diffusion path for deleterious species [34].
Chromate based pigments provide high corrosion resistance. However,
because of the environmental rules, more demands are being made for
alternative inorganic filler particles [35].
In this work, studies have been made in order to introduce new
generation of epoxy coatings mostly based on new hydrogenphosphate
compounds (NH4)2[Mg(H2O)6]3(HPO3)4.
In fact, the the hydrogenophosphates represent a family of compounds
with great potential for the generation of new proton conductors. A great
deal of theoretical and experimental work has been devoted to protonic
conductors [36,37], due to their potential as electrolyte for the production
of electricity in hydrogen fuel cells.
The present study is a continuation of our contribution in the
application of phosphates as antiꢀcorrosive compounds [38ꢀ41].
We hereby evaluate the effect the effect MgHP on the mechanical and
antiꢀcorrosion performance of epoxyꢀcoated carbon steel during
immersion in 3.5% NaCl solution using electrochemical techniques and
morphology analysis.
2. Experimental
2.1. Synthesis of (NH4)2[Mg(H2O)6]3(HPO3)4
4

Page 7 of 32
Dalton Transactions
Page 8 of 33
View Article Online
DOI: 10.1039/C6DT04572C
1.0 g of magnesium oxide (MgO) was added to a solution of 4.0 g
phosphorous acide H3PO3 dissolved in 15 mL water (S1), which was
stirred for 1 h at 333 K. An equimolar preparation of another solution
(S2), containing (NH4)2HPO3, was added. The two solutions S1 and S2
were mixed and stirred for 1 h at room temperature, after which the
obtained precipitate was filtered out. The filtrate was allowed to stand at
room temperature. After 2 weeks, colorless crystals are obtained; they
were washed with an ethanolꢀwater (80–20%).
2.2. Preparation of coating and coated samples
The coating formula was made by mixing epoxy resin (Bisphenol –
from Ciba Co.), polyamidoamine hardener (CRAYAMIDꢀ from Arkema
Co.) and different concentrations (from 0.2% to 1.0%) of MgHP. The
weight ratio of the epoxy resin to the hardener was 2:1. All the contents
were mixed using a speed mixer (H500 homogenizer form POLꢀEKOꢀ
APARATURA) for 30 min.
Carbon steel sheets (industrial grade) were used as the substrates. The
test sheets (15 mm × 20 mm × 0.70 mm) were pretreated by mechanical
cleaning, degreasing in an acetone solution and rinsing with distilled
water.
The clean carbon steel substrate was dipped into the finally coating
formula for one time and then kept in an oven at 393 K for 1.0 h to allow
full curing. Dry film thickness for all samples was 80 ± 10 ꢁm.
5

Page 9 of 33
Dalton Transactions
Page 8 of 32
View Article Online
DOI: 10.1039/C6DT04572C
2.3. Test of the corrosion protection performance
For investigation of the corrosion protection performance of coating
systems, the electrochemical impedance spectroscopy (EIS)
measurements were measured using EGꢀG 273 potentiostat/ galvanostat.
A three electrode cell design was used for electrochemical experiments.
The cell was constructed with platinum as an auxiliary electrode, coated
carbon steel as a working electrode and saturated calomel electrode
(SCE) as a reference electrode.
Impedance spectra were conducted at open circuit potential (OCP),
using the frequency range of 0.01 Hz to 100 kHz. The extracted
parameters were calculated by using ZꢀView program software. All
electrochemical tests were performed in 3.5 wt% NaCl in distilled water.
Experiments were conducted after 7 days of immersion.
2.4. Complementary studies
Mechanical properties include hardness and reduced modulus were
determined using nanoꢀindentation technique (NanoTest Vantage, Micro
Materials instruments).
Surface morphological studies of the coatings after 7.0 days of
completed immersion in corrosive solution were evaluated using FEꢀSEM
Model Quanta 250 (FEI Company, Netherlands).
2.5. Infrared spectrum
6

Page 9 of 32
Dalton Transactions
Page 10 of 33
View Article Online
DOI: 10.1039/C6DT04572C
Infrared spectrum of the title compound was recorded, as suspension
powder in KBr, on a PerkinꢀElmer Spectrometer 1750, in the range 4000–
400 cmꢀ1.
3. Results and discussion
3. 1 Crystal structure
The structure of (NH4)2[Mg(H2O)6]3(HPO3)4 was fully elucidated by
Missouri et al. [18] and later reproduced by Abdellah et al. [19]. Its
crystal structure is described as a framework made up of isolated
[Mg(H2O)6]2+, [(HPO3)]2ꢀ and [NH4]+ groups that interconnect through an
intricate network of hydrogen bonds (Fig. 1). Fig. 2 depicts projection of
the crystal structure onto (001)ꢀcrystallographic plane.
3.2. IR study
Fig. 3 shows the IR spectrum of the title compound. The presence of PꢀH
bonds is confirmed by IRꢀband band at 2440 cmꢀ1, which is ascribed to
the stretching vibrations of P–H from the HPO3. The bands in the region
ꢀ1
1040–979 cm indicate the deformation vibration of P–H bond [42,43],
ꢀ1
ꢀ1
while those at 1260 cm and 1064 cm correspond to the stretching
vibrations (νas) of PO group. The vibrations of PO groups appear as
3
3
ꢀ1
bands in the range of 620ꢀ450 cm . The strong and broad band in the
ꢀ1
region 3550ꢀ3414 cm is due to the stretching vibration of the water
+
molecule and the NH ion [44]. The intense bands at 1636 and 1617
4
7

Page 11 of 33
Dalton Transactions
Page 10 of 32
View Article Online
DOI: 10.1039/C6DT04572C
ꢀ1
cm are associated to the deformation vibrations of O–H bonds of water,
and the bands at 1470 and1417 cmꢀ1 are disturbed to the deformation
+
vibrations of NH group [45ꢀ46].
4
3.3. Evaluation of corrosion protection performance
Electrochemical impedance spectroscopy (EIS) has been exceedingly
utilized as a nonꢀdestructive system to investigate the corrosion
protection performance of coating [47]. In this part, the performance of
epoxyꢀcoated carbon steel in the absence and presence of different
concentrations of MgHP immersed in 3.5% NaCl solution was assessed
by assigning Nyquist plots (see Fig. 4). As shown in Fig. 4, the Nyquist
plots for neat epoxy coating has consisted of two circuits capacitive
loops. The two capacitive loops at high and low frequency are due to the
resistance and capacitance of the epoxy coating and the steelꢀelectrolyte
interface, respectively [48]. Equivalent electric circuit with two time
constants for neat epoxy coating was shown in Fig. 5. In this pattern, Rs is
the solution resistance, Rp polarization resistance, Cdl the double layer
capacitance at the metal and coating interface, Rpo is the pore resistance
and Cc is the coating capacitance.
The incorporation of 0.2% and 0.4% of MgHP increased the diameter
of the two capacitive loops. This means that the addition of 0.2% and
0.4% of MgHP leads to enhance the antiꢀcorrosion performance of epoxy
8

Page 11 of 32
Dalton Transactions
Page 12 of 33
View Article Online
DOI: 10.1039/C6DT04572C
coating, but still the efficiency of epoxy film not high to prevent the
passage of corrosive ions into metal surface. The same equivalent electric
circuit that used for describing the neat epoxy coating system can be used
for fitting EIS data for epoxy coating containing 0.2% and 0.4% of MgHP
(Fig. 5).
On the other hand, the significant changes in the antiꢀcorrosion
performance of epoxy coating were noticed with the change in MgHP
concentration. The optimum coating performance was obtained at 0.8%
and 1.0% concentration of MgHP. It is further seen that the incorporation
of 0.8% and 1.0% concentration of MgHP has resulted in formation one
time constant loop. The corresponding equivalent electric circuit can be
presented in Fig. 6.
The fitted EIS parameters for epoxyꢀcoated carbon steel in the absence
and presence of different concentrations of MgHP are shown in Table 1.
It has been reported from Table 1 that the incorporation of MgHP into the
epoxy coating significantly increased Rpo,Rp and reduced Cc,Cdl,
indicating enhanced coating performance in the presence of MgHP.
Epoxy coatings generally diminish the corrosion of carbon steel liable to
corrosive solutions in two procedures [49,50]. First, they act as a physical
barrier film to control the entry of corrosive species. Second, they can
serve as a reservoir for corrosion inhibitors to aid the steel surface in
resisting attack by aggressive species. After a certain amount of time,
9

Page 13 of 33
Dalton Transactions
Page 12 of 32
View Article Online
DOI: 10.1039/C6DT04572C
corrosive ions penetrate into the coating and form a new liquid/metal
interface under the coating. Corrosion phenomena can occur at this new
interface.
In the case of neat epoxy coating, it is impossible to prevent enough
moisture transmission through coating films to control the cathode
reaction by moisture deprivation.
The electrochemical reactions
occurring at the defect points in the coating film can be summarizes in the
following equations [51,52]:
Fe(s) → Fe2+(aq) + 2e anodic reaction
(1)
4e +2O2(aq) + 2H2O → 4OH− cathodic reaction (2)
The incorporation of MgHP with epoxy leads to formation of
impermeable barrier coatings to suppress both oxygen transmission and
the transmission of corrosion ions to a sufficient extent that corrosion
may be impeded. This behavior is due to the fact that MgHP compound
has great surface activity so it can absorb more epoxy resin on its surface.
This enhances the density of the coating thereby reducing the transport
paths for the corrosive electrolyte to pass through the coating system [53].
Moreover, the presence of Mg+2 ions in the structure of MgHP serves to
prevent corrosion galvanically by acting as the anode of an
electrochemical cell of which the steel substrate is the cathode [54]. This
means that MgHP containing coatings gives a cathodic protection to the
steel substrate.
10

Page 13 of 32
Dalton Transactions
Page 14 of 33
View Article Online
DOI: 10.1039/C6DT04572C
3.4. Water uptake of coating
Owing to the fact that the corrosion through coating system resulting
from the contact between the substrate and the corrosive environment, the
measurements of the water uptake of coating (Wc) is essential to
determine the corrosion resistance of coating. The quantification of water
uptake by a coating was derived from coating capacitance (Cc), according
to Haruyama et al. [55].
Wc = [log(Ct/C0) / log(εH2O)] × 100
(3)
where C0 and Ct are respectively the initial capacitance and the one at a
time t; εH2O being the dielectric constant of water at the working
temperature.
The relative volume fraction of water uptake by a coating in the
absence and presence of different concentrations of MgHP is plotted
against the immersion period (see Fig. 7). As shown in Fig. 7, the coating
film absorbed water rapidly at initial stage of immersion, and then the
rate of water uptake showed only a slightly increase with time. It is clear
that water uptake by epoxy coating decrease by the additions of MgHP
compound. The amount of water absorbed into epoxy coating film is
virtually dependent on the concentration of MgHP. The lowest amount
was obtained at 1.0% concentration of MgHP. The low water uptake of
epoxy coating containing MgHP compound, gives further support that the
11

Page 15 of 33
Dalton Transactions
Page 14 of 32
View Article Online
DOI: 10.1039/C6DT04572C
role of the MgHP in improving the antiꢀcorrosive performance of these
epoxy coatings [56].
3.5. Evaluation of mechanical properties
The mechanical properties of epoxyꢀcoated carbon steel in the absence
and presence of different concentrations of MgHP were inspected using
the nanoꢀindentation technique. From loadingꢀunloading curves, hardness
and reduced modulus of the coatings were determined and listed in Table
2 [31]. It clearly showed that the epoxy coating modified with MgHP
offered a significantly enhanced hardness and reduced modulus of the
coatings. The optimum hardness and reduced modulus were obtained at
1.0% concentration of MgHP. This behavior can be attributed due to two
factors. First one, the MgHP particles tend to occupy pinholes and spaces
in the epoxy coating, causing a reduction of the total free volume and an
enhancement of the crossꢀlinking density of the cured epoxy [34,57].
Second factor, MgHP particles prevent epoxy disaggregation during
curing and result in a more homogenous coating [57].
3.6. Surface morphological studies
Typical SEM images of the epoxyꢀcoated carbon steel in the absence
and presence of different concentrations of MgHP after 7.0 days of
completed immersion in 3.5% NaCl solution are shown in Fig. 8. As
clearly seen in this figure, corrosive electrolyte penetration to the
interface between the coating and the substrate took place. This caused
12

Page 15 of 32
Dalton Transactions
Page 16 of 33
View Article Online
DOI: 10.1039/C6DT04572C
weak adhesion between the coating and the substrate. Creaking in coating
film was observable in the absence of MgHP. However, a small fractal
flakes growth patterns was observed over the surfaces of the specimens
coated with epoxy coating containing 0.2% and 0.4%. On other hand, the
presence of 0.8% and 1.0% of MgHP improved significantly the texture
of the epoxy coating. In addition, there are no blisters and/or pinꢀholes.
4. Conclusions
Crystals of (NH4)2[Mg(H2O)6]3(HPO3)4 (MgHP) were synthesized by a
wet chemistry route and characterized by IR spectroscopy. The effect of
varying MgHP concentration on antiꢀcorrosion and mechanical properties
of epoxy coating has been studied. The EIS measurements indicated that
the incorporation of MgHP particles increased the coating resistance and
polarization resistance while reducing the coating capacitance and the
double layer capacitance. Compared to neat epoxy resin, the epoxy
coating containing MgHP particles exhibit better antiꢀcorrosion and
mechanical properties. The permeability of the epoxy coating can be
adjusted by the loading and concentration of MgHP particles. The lowest
water uptake by epoxy coating was obtained at 1.0% concentration of
MgHP.
References
[1]A.K. Cheetham, G. Férey, T. Loiseau, Angew. Chem. Int. Ed. 38
(1999) 3268ꢀ3292.
13

Page 17 of 33
Dalton Transactions
Page 16 of 32
View Article Online
DOI: 10.1039/C6DT04572C
[2]P. Feng, X. Bu, N. Zhang, Acc. Chem. Res. 38 (2005) 293ꢀ303.
[3]E.R. Parnham, R.E. Morris, Acc. Chem. Res. 40 (2007) 1005ꢀ1013.
[4]S. Natarajan, S. Mandal, Angew. Chem. Int. Ed. 47 (2008) 4798ꢀ
828.
[5]J. Jiang, J. Yu, A. Corma, Angew. Chem. Int. Ed. 49 (2010) 3120ꢀ
3145.
[6]G. Bonavia, J. Debord, R.C. Haushalter, D. Rose, J. Zubieta,
Chem. Mater. 7 (1995) 1995ꢀ1998.
[7]S. Fernandez, J.L. Pizarro, J.L. Mesa, L. Lezama, M.I. Arriortua,
R. Olazcuaga, T. Rojo, Chem. Mater. 14 (2002) 2300ꢀ2307.
[8]S. Fernandez, J.L. Mesa, J.L. Pizarro, L. Lezama, M.I. Arriortua,
T. Rojo, Angew. Chem. Int. Ed. 41 (2002) 3683ꢀ3685.
[9]J. Liang, Y. Wang, J. Yu, R. Xu, Chem. Commun. 7 (2003) 882ꢀ
883.
[10]
W.T.A. Harrison, M.L.F. Phillips, T.M. Nenoff, J. Chem.
Soc., Dalton Trans. 17 (2001) 2459ꢀ 2461.
[11]
W. Fu, Z. Shi, D. Zhang, G. Li, Z. Dai, X. Chen, S. Feng, J.
Solid State Chem. 174 (2003) 11ꢀ18.
[12]
Chem. 170 (2003) 303ꢀ307.
[13] W. Dong, G. Li, Z. Shi, W. Fu, D. Zhang, X. Chen, Z. Dai,
Y. Wang, J. Yu, Y. Li, Y. Du, R. Xu, L. Ye, J. Solid State
L. Wang, S. Feng, Inorg. Chem. Commun. 6 (2003) 776ꢀ780.
14

Page 17 of 32
Dalton Transactions
Page 18 of 33
View Article Online
DOI: 10.1039/C6DT04572C
[14]
M.D. Marcos, P. Amorós, F. Sapina, A.B. Porter, R.M.
Mánez, J.P. Attfield, Inorg. Chem. 32 (1993) 5044ꢀ5052.
[15]
S.H. Shi, W. Qian, G.H. Li, L. Wang, H.M. Yuan, J.N. Xu,
G.S. Zhu, T.Y. Song, S.L. Qiu, J. Solid State Chem. 177 (2004)
3038ꢀ3043.
[16]
342ꢀ346.
[17] R. Ouarsal, A.A.Tahiri, M. Lachkar, M. Dusek, K.
Fejfarova, B. El Bali, Acta Cryst. E59 (2003) i33ꢀi35.
D.R. Powell, S.K. Smith, T.C Farrar, Acta Cryst. C50 (1994)
[18]
Messouri, B. El Bali, F. Capitelli, J.F. Piniella, M. Lachkar,
Z. Slimani, Acta Cryst. E61 (2005) i129ꢀi131.
[19]
K.I. Abdallah, S. Mohamed, R. Mohamed, G. Abdelhalim,
Acta Cryst. C62 (2006) i43ꢀi45.
[20]
M.A. Migahed, M.M. Attya, S.M. Rashwan, M. Abd Elꢀ
Raouf, A.M. AlꢀSabagh, Egypt. J. Petrol. 22 (2013) 149–160.
[21]
A.M. AlꢀSabagh, H.M. AbdꢀElꢀBary, R.A. ElꢀGhazawy,
M.R. Mishrif , B.M. Hussein, Egypt. J. Petrol. 21 (2012) 89–100.
[22]
(2016) 111ꢀ121.
[23] Elsadig O. Eltai, J.D. Scantlebury, E.V. Koroleva, Prog. Org.
Coat. 76 (2013) 548ꢀ554.
S. Ranade, M. Forsyth, M.Y.J. Tan, Prog. Org. Coat. 101
15

Page 19 of 33
Dalton Transactions
Page 18 of 32
View Article Online
DOI: 10.1039/C6DT04572C
[24]
C. H. Hare, “Anticorrosive barrier and inhibitive primers,”
Federation Series on Coatings Technology. Philadelphia, PA:
Federation of Societies for Coatings Technology, 1979.
[25]
A.W. Peabody, Control of Pipeline Corrosion, 2nd ed., R.L.
Bianchetti, Ed., NACE International, 2001.
[26]
R. Norsworthy, Coatings used in conjunction with cathodic
protection – shielding vs. nonꢀshielding pipeline coatings. Paper
No. 4017, NACE International, 2009.
[27]
M.A. Deyab, J. Power Sources 268 (2014) 50ꢀ55.
M.A. Deyab, Prog. Org. Coat. 85 (2015) 146–150.
W. Yang, Q. Li, Q. Xiao, J. Liang, Prog. Org. Coat. 89
[28]
[29]
(2015) 260ꢀ266.
[30]
M.A. Deyab, K. Eddahaoui, R. Essehli, S. Benmokhtar,
T. Rhadfi, A. De Riccardis , G. Mele, J. Mol. Liq. 216 (2016)
699–703.
[31]
(2016) 513–517.
[32]
19.
[33]
406ꢀ411.
M.A. Deyab, A. De Riccardis, G. Mele, J. Mol. Liq. 220
A. Kalendova, D. Vesely, Prog. Org. Coat. 64 (2009) 5–
M.A. Deyab, S.T. Keera, Mater. Chem. Phys. 146 (2014)
16

Page 19 of 32
Dalton Transactions
Page 20 of 33
View Article Online
DOI: 10.1039/C6DT04572C
[34]
X. Shi, T. Nguyen, Z. Suo, Y. Liu, R. Avc, Surf. Coat.
Technol. 204 (2009) 237–245.
[35]
Y. Qian, Y. Li, S. Jungwirth, N. Seely, Y. Fang, X. Shi, Int.
J. Electrochem. Sci. 10 (2015) 10756 – 10780.
[36]
[37]
K. D. Kreuer, Solid State Ionics, 149 (2000) 136.
F. A. Itoua Ngopoh, M. Lachkar , T. Đorđević , C. L.
Lengauer , B. El Bali, J. Chem. Crystallogr. 45 (2015) 369–375.
[38] M. A. Deyab, R. Essehli, B. El Bali, RSC Adv. 5 (2015)
64326–64334.
[39]
M. A. Deyab, R. Essehli, B. El Bali, RSC Adv. 5 (2015)
48868–48874.
[40]
M. A. Deyab, R. Ouarsal, M. Lachkar, B. El Bali, R. Essehli,
J. Mol. Liq. 219 (2016) 994ꢀ999.
[41]
M. A. Deyab, B. El Bali, R. Essehli, R. Ouarsal, M. Lachkar,
H. Fuess, J. Mol. Liq. 212 (2016) 636ꢀ640.
[42]
Ouarsal, R., EL Bali, B., Lachkar, M., Dusek, M., Fejfarovà,
K., Acta Cryst., E61 (2005) i168–i170.
[43]
Ouarsal, R., EL Bali, B., Lachkar, M., Dusek, M., Fejfarovà,
K., Acta Cryst., E61 (2005) i171–i173.
[44]
K. Nakamoto: (Ed.), Infrared and Raman Spectra of
Inorganic and Coordination Compounds, Part A, 5th ed., John
Wiley & Sons, New York, 1997.
17

Page 21 of 33
Dalton Transactions
Page 20 of 32
View Article Online
DOI: 10.1039/C6DT04572C
[45]
Ram. Spectr., 35 (2004) 41ꢀ46.
[46] Philip, D. B., Lizbeth, B., Aruldhas, G., J. Ram. Spectr., 21
(1990) 523ꢀ524.
[47]
Brouzi, K., Ennaciri, A., Harcharras, M., Capitelli, F., J.
D. Loveday, P. Peterson, B. Rodgers, JCT coatings tech., 2
(2004) 22ꢀ27.
[48]
S.P. Tambe, S.K. Singh, M. Patri, D. Kumar, Prog. Org.
Coat. 72 (2011) 315ꢀ320.
[49]
J.J. Suay, M.T. Rodriguez, K.A. Razzaq, J.J. Carpio, J.J.
Saura, Prog. Org. Coat. 46 (2003) 121–129.
[50] V.B. Miiskovic, M.R. Stanic, D.M. Drazic, Prog. Org. Coat.
36 (1999) 53ꢀ63.
[51]
1742.
M. A. Deyab, J. Solid State Electrochem. 13 (2009) 1737–
[52]
[53]
M.A. Deyab, Desalination 384 (2016) 60–67.
M. Rashvanda, Z.Ranjbara, Prog. Org. Coat. 76 (2013)
1413–1417.
[54]
A.A. Tracton, Coatings Materials and Surface Coatings,
S. Haruyama, M. Asari, T. Tsuru, Corrosion Protection by
CRC Press, Florida, 2006.
[55]
Organic Coatings. Electrochemical Society Proceedings, 87ꢀ2,
1987, p. 197.
18

Page 21 of 32
Dalton Transactions
Page 22 of 33
View Article Online
DOI: 10.1039/C6DT04572C
[56]
J.H. Park, G.D. Lee, A. Nishikata, T. Tsuru, Corros. Sci. 44
O. Becker, R. Varley, G. Simon, Polymer 43 (16) (2002)
(2002) 1087–1095.
[57]
4365ꢀ 4373.
19

Page 23 of 33
Dalton Transactions
Page 22 of 32
View Article Online
DOI: 10.1039/C6DT04572C
List of Figures
Fig. 1. View of the Mg(H2O)6, HPO3 and NH4 coordination polyhedra.
Dashed lines indicate hydrogen bonds; displacement ellipsoids are
drawn at the 50% probability level. [Symmetry codes: (i) x, ꢀy, z;
(ii) x, 1ꢀ y, z; (iii) ꢀx, 1ꢀ y,ꢀz; (iv) ꢀx, y,ꢀz.].
Fig. 2. Projection of the crystal structure onto (001)ꢀcrystallographic
plane.
Fig. 3. IR spectrum of (NH4)2[Mg(H2O)6]3(HPO3)4 compound.
Fig. 4. Nyquist plots of epoxyꢀcoated carbon steel in the absence and
presence of different concentrations of MgHP immersed in 3.5%
NaCl solution at 298K.
Fig. 5. Equivalent electric circuit for neat epoxy and epoxy coating
containing 0.2% and 0.4% of MgHP.
Fig. 6. Equivalent electric circuit for epoxy coating containing 0.8% and
1.0% of MgHP.
Fig. 7. The percentage of water uptake by epoxy coating in the absence
and presence of different concentrations of MgHP against the
immersion period.
Fig. 8. SEM images of the epoxyꢀcoated carbon steel in the absence and
presence of different concentrations of MgHP after 7.0 days of
completed immersion in 3.5% NaCl solution.
20

Page 23 of 32
Dalton Transactions
Page 24 of 33
View Article Online
DOI: 10.1039/C6DT04572C
Table 1: EIS parameters of epoxyꢀcoated carbon steel in the absence and
presence of different concentrations of MgHP immersed in 3.5% NaCl
solution at 298K.
System
Rpo × 108 Cc × 10ꢀ11 Rp ×108
Cdl × 10ꢀ11
F cmꢀ2
04.99
02.32
01.25
ꢀ
F cmꢀ2
ꢀ cm2
07.20
15.02
26.42
39.95
42.22
ꢀ cm2
05.98
22.20
45.11
ꢀ
Epoxyꢀcoated
2.25
Epoxyꢀcoated + 0.2% MgHP
Epoxyꢀcoated + 0.4% MgHP
Epoxyꢀcoated + 0.8% MgHP
Epoxyꢀcoated + 1.0% MgHP
1.02
0.57
0.35
0.15
ꢀ
ꢀ
21

Page 25 of 33
Dalton Transactions
Page 24 of 32
View Article Online
DOI: 10.1039/C6DT04572C
Table 2: The hardness and reduced modulus of the coatings of epoxyꢀ
coated carbon steel in the absence and presence of different
concentrations of MgHP.
System
Hardness
(GPa)
Reduced modulus
(GPa )
Epoxyꢀcoated
0.132
0.168
0.187
0.445
0.699
2.89
3.41
3.78
3.82
4.20
Epoxyꢀcoated + 0.2% MgHP
Epoxyꢀcoated + 0.4% MgHP
Epoxyꢀcoated + 0.8% MgHP
Epoxyꢀcoated + 1.0% MgHP
22

Page 25 of 32
Dalton Transactions
Page 26 of 33
View Article Online
DOI: 10.1039/C6DT04572C
Fig.1
23

Page 27 of 33
Dalton Transactions
Page 26 of 32
View Article Online
DOI: 10.1039/C6DT04572C
Fig. 2
24

Page 27 of 32
Dalton Transactions
Page 28 of 33
View Article Online
DOI: 10.1039/C6DT04572C
Fig.3
25

Page 29 of 33
Dalton Transactions
Page 28 of 32
View Article Online
DOI: 10.1039/C6DT04572C
Fig. 4
26