K.I. Aly et al.
Reactive and Functional Polymers 166 (2021) 105001
surface is efficiently inhibited whereas safeguarding the elimination of
X65-steel interface corrosion yields [17,18]. These molecules which
protect the X65-steel characteristics are well-defined as corrosion
inhibitors.
2.3. Synthesis of monomers
2.3.1. Preparation of 4-[3-(4-hydroxyphenyl)-2-phenyl-3,3a,4,5,6,7-
hexahydro-2H-7 indazoly-lidenmethyl] phenol (III)
Corrosion inhibitors are usually classified as an organic and inor-
ganic inhibitors. The organic corrosion additive has definite features,
usually comprises sulfur (S), nitrogen (N), and oxygen (O) conjugated
groups [19–25]. These conjugated groups could produce a coordination
bond through their specific electrons lone pair with the empty 3d-orbital
of the iron atom to be efficiently adsorbed on the iron interface. Among
the organic molecules, polymeric corrosion additives are very exten-
sively selected due to their enormous effective groups and their ability to
form a complex with (Fe) ions at the surface [26,27].
A mixture of phenyl hydazine (1.08 g, 0.01 mol) and 2,6-bis(4-
hydroxybenzylidene) cyclohexanone (I) (3.06 g, 0.01 mol) in 100.0 ml
methanol was stirred under reflex for 7 h. The mixture of reaction was
then permitted to cool and was reserved at 0 ◦C for 24 h. The formed
compound was filtered, washed with methanol then with Petroleum-
benzin 60-80o and recrystallized from dioxane. Yellow precipitated
was obtained, m.p. 260–262 ◦C. 1H NMR (δ/ DMSO); 9.50 (s, 2H, 2OH),
7.50–6.60 (m, 14H, Ar + =CH), 5.97(m, 1H, CH a), 3.36(m, 1H, CH b),
2.80–2.70 (m, 4H, 2CH2 c,e), 1.82 (m, 2H, CH2 d) (Fig.S1; ESI). IR (KBr,
ν
So, the aim of our work is the preparation of new unsaturated
polyesters Va-d and VIa-d via interfacial polycondensation technique
from di hydroxy monomeric units containing indazoline ring 4-[3-(4-
hydroxyphenyl)-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-7 indazolylidene-
methyl]-phenol (III) and 4–7-[1-(4-hydroxy-3-methoxyphenyl)-meth-
ylidene]-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-3-indazolyl-2- methox-
yphenol (IV), with different acid chlorides and studying the effect of
indazoline moiety on polymer's properties. Moreover, their anti-
corrosion properties for X65-steel in molar H2SO4 were inspected and
supported by surface morphology analysis.
cmꢀ 1); 3532 cmꢀ 1 (OH), 1606 cmꢀ 1 (C=N), 1591 cmꢀ 1 (C=C) (Fig.S2;
ESI). Mass spectrum (Fig.S3; ESI) exhibited a molecular ion-peak at m/z
= 396 which in matched with its molecular structure (C26H24N2O2).
Anal. Calcd (Mol. Weight 396.49): H, 6.10%, C, 78.76%, N, 7.07%.
Found: H, 6.08%, C, 78.74%, N, 7.05%.
2.3.2. Synthesis of 4–7-[1-(4-hydroxy-3 methoxyphenyl)methylidene]-2-
phenyl-3,3a,4,5,6,7-hexahydro-2H-3-indazolyl-2-methoxyphenol (IV)
This compound was synthesized as designated in the previous route,
using 2,6-bis(4-hydroxy-3-methoxybenzylidene) cyclohexanone (II),
recrystallized from ethanol, yellow precipitate, 92%, m.p 174–176 ◦C.
1H NMR, (δ /DMSO): 9.10–8.94 (s, 2H, 2OH), 7.54–6.62 (m, 12H, Ar +
=CH), 6.01(m,1H, CH a), 3.83–3.73 (s, 6H, 2OCH3) 3.23 (m, 1H, CH b),
2.80–2.70 (m, 4H, 2CH2), 1.80 (m, 2H, CH2). IR, v 3532 (OH), 1591
(C=N), 1515 cmꢀ 1 (C=C) (Fig.S4; ESI). Anal. Calcd for (C28H24N2O2)
(456.55): H, 6.18%, C, 73.66%, N, 6.14%. Found: C, 73.64%, H, 6.16%,
N, 6.12.
2. Experimental
2.1. Materials and reagents
All commercially available reagents were purchased from Merck,
Aldrich, and Fluka and were used without further purification. All re-
actions were monitored by a thin layer chromatography (TLC) using
percolated plates of silica gel G/UV-254 of 0.25 mm thickness (Merck
60 F 254) using UV light (254 nm/365 nm) for visualization. Melting
points were detected with a Kofler melting point apparatus and cor-
rected. Infrared spectra were recorded with an FT-IR-Bruker, spec-
trometer and are given as cm-1using the attenuated total reflection
(ATR) method.
2.4. Synthesis of model polymers
2.4.1. Overall procedure
A
mixture of 4-[3-(4-hydroxyphenyl)-2-phenyl-3,3a,4,5,6,7-hex-
ahydro-2H-7 indazolyliden-methyl]phenol (III) or 4–7-[1-(4-hydroxy-3-
methoxyphenyl) methylidene]-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-3-
indazolyl-2-methoxyphenol (IV) (5 mmol) in NaOH solution (10 mmol,
Isophthaloyl dichloride and terephthaloyl chloride (Aldrich) were
recrystallized from n-hexane (m.p. 317 K) and n-hexane (m.p. 356–357
K), respectively, freshly bidistilled sebacoyl dichloride at 182 ◦C/16 Torr
and adipoyl dichloride at 125 ◦C/11 Torr were utilized. NaOH with
analytical grade. 4-Hydroxybenzaldehyde, 4-hydroxy-3-methox-
ybenzaldehyde (Merck), phenyl hydrazine (98%), cyclohexanone
(Aldrich), and benzoyl chloride were used without purification. All
other materials were utilized in high purity following refining by normal
approaches.
◦
10 ml) was stirred at 25 C for 2 h. Benzoyl chloride (10 mmol) was
added carefully within 20 min. With continuous stirring for an addi-
tional 1.0 h. The isolated solid yield was composed by filtration, washed
with H2O, dried, and recrystallization from the suitable solvent.
2.4.2. Synthesis of 1-phenylcarbonyloxy-4-[2-phenyl-3-(4-phenylcarbonyl-
oxyphenyl)-3,3a,4,5,6,7-hexahydro-2H-7-indazolylidenmethyl]benzene (a)
The obtained precipitate was crystallization from benzene, yellow
ꢀ 1
ppt, 87.06%, m.p. 200 ◦C, IR (KBr):1722 cm (C O (s) ester group),
–
–
1663 cmꢀ 1 (C=N), 1596 cmꢀ 1 (C=C) (Fig.S5; ESI). 1H NMR (δ/DMSO);
8.17–7.39 (m, 24H, Ar + =CH), 4.49–4.41 (d,1H,Ha), 3.77–3.44 (m,1H,
Hb), 2.33–2.22 (t, 2H, He), 1.41–1.34 (m, 2H,Hc), 1.27–1.21 (m, 2H,
Hd).
2.2. Measurement
NMR spectra were performed on a Bruker Bio Spin AG spectrometer
at 400 MHz in dimethyl sulfoxide (DMSO‑d6) using an internal reference
as TMS. FTIR spectra were analyzed using a Bruker Tensor 27 spectro-
photometer by KBr disk method and also a Scanning Spectrophotometer
(Shimadzu 2110 PC) was used. D8 ADVANCED (BRUKER) X-ray
diffractometer is used in getting XRD at 25 ◦C by using Nickel-filtered
2.4.3. Synthesis of 2-methoxy-4-[3-(3-methoxy-4-
phenylcarbonyloxyphenyl)-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-7-
indazolylidenmethyl]-1-phenylcarbonyloxybenzene (B)
The precipitate obtained IR (KBr) 1736 cmꢀ 1 (C
O
(s) ester group),
–
–
Copper Kα radiation. TGA studies were inspected at a heating rate of
1597 cmꢀ 1 (C=N), 1500 cmꢀ 1 (C=C) (Fig.S6; ESI). 1H NMR (δ / DMSO);
8.5 (s,1H, =CH), 8.14 (s, 2H, CH aromatic anisyl), 7.76–7.12 (m, 4H,
10 ◦C/min in N2 atmosphere using a DuPont 2000 thermal analyzer. The
morphology of selected samples of polyesters Va-d and VIa-d was scanned
by SEM. The materials were set by placing a smooth portion of the
polymer sample on a Cu-holder and subsequently covering it with pal-
ladium‑gold alloy. SEM pictures were obtained using a low-dose method
from a Camera Penta Z-50 p at an accelerating voltage of 20 kV.
–
–
Ar H aromatic anisyl), 7.12–6.71 (m,15H, Ar H aromatic), 3.85 (S,
6H, 2OCH3), 4.51–4.44 (d,1H,Ha), 3.78–3.43(m,1H, Hb), 2.31–2.24 (t,
2H, He), 1.40–1.31 (m, 2H,Hc), 1.25–1.19 (m, 2H, Hd).
2.5. Preparation of polyesters Va-d and VI a-d
In a 3-necked flask containing a desiccated N2 inlet-outlet, and
condenser, dropping funnel, a mixture of 4-[3-(4-hydroxyphenyl)-2-
2