Synthesis of: N -[(2-hydroxyethoxy)carbonyl]glycine from carbon dioxide, ethylene oxide, and α-amino acid by ionic gelation of sodium tripolyphosphate (TPP) and spirulina supported on magnetic KCC-1 in aqueous solution

Article abstract of DOI:10.1039/c8nj01333k

In this study, a novel ionic gelation (IG) of sodium tripolyphosphate (TPP) and spirulina was prepared that, supported on magnetic fibrous silica nanospheres (Fe₃O₄/KCC-1/IG), has been developed for the synthesis of N-[(2-hydroxyetho

Full text of DOI:10.1039/c8nj01333k

NJC
View Article Online
View Journal
PAPER
Synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine
from carbon dioxide, ethylene oxide, and a-amino
acid by ionic gelation of sodium tripolyphosphate
(TPP) and spirulina supported on magnetic KCC-1
in aqueous solution
Cite this:DOI: 10.1039/c8nj01333k
a
Rahele Zhiani,a Mehdi Khoobibc and Seyed Mohsen Sadeghzadeh
*
In this study, a novel ionic gelation (IG) of sodium tripolyphosphate (TPP) and spirulina was prepared
that, supported on magnetic fibrous silica nanospheres (Fe3O4/KCC-1/IG), has been developed for the
synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine from carbon dioxide, ethylene oxide, and a-amino
acid. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported ionic
gelation. The Fe3O4/KCC-1/IG MNPs were thoroughly characterized by using TEM, FESEM, VSM, FT-IR,
TGA, and BET. We supported an ionic gelation on the surface of silica and used spirulina and TPP as a
catalyst; the observations were exploited in the direct and selective chemical fixation of CO2 to afford
high degrees of CO2 capture and conversion.
Received 18th March 2018,
Accepted 9th May 2018
DOI: 10.1039/c8nj01333k
rsc.li/njc
They contain reactive (amino and hydroxyl) functional groups,
providing biocompatibility, low-toxicity and pH-sensitivity, as
Introduction
The conversion of carbon dioxide into value-added organic well as metal anchoring functional groups.25–28
compounds continues to be a vivid area of research in academic
The incorporation of magnetic nanoparticles (MNPs) into an
and industrial settings. The valorization of CO2 is important to amino and hydroxyl group containing network, using a poly-
create value from a waste material, and current efforts have anionic cross-linker such as tripolyphosphate (TPP),29–31 allows
already shown great potential towards the use of CO2 to store the interaction of MNPs with the cationic spirulina through
energy, and as a synthon for the creation of new polymers and fine electrostatic interactions; at the same time, spirulina forms
chemicals. Another area of widespread interest and importance strong interactions with MNPs because of its good chelating
concerns the preparation of organic carbonates. More recently, ability with metal ions. The use of a physical cross-linking agent
focus has been shifted towards the use of these carbonates as (TPP) instead of a chemical cross-linker (such as glutaraldehyde)
intermediates in organic synthesis.1–19 An attractive route towards prevents toxicity of the reagents. Recently, Polshettiwar et al.32
the conversion of cyclic carbonates into useful products concerns reported a novel fibrous silica nanosphere (KCC-1) material,
their aminolysis by aliphatic amines, thus affording N-alkyl which has special center-radial pore structures with the pore
carbamate structures.20–24
sizes gradually increasing from the center to the surface. The
Algae are naturally abundant and found in all kinds of KCC-1 material showed high specific surface area due to the
aquatic environments. Among algae species, Spirulina platensis pores in the fibers, and the accessibility of the active sites was
is a photosynthetic, filamentous, spiral-shaped, multicellular, significantly increased as a result of the special structure.33–37
and bluegreen microalgae. Spirulina filaments may be easily Additionally, the 3-D architecture-generated hierarchical pore
separated from their medium, have high digestibility and a structure with macropores can also improve the mass transfer
mild flavor, and contain up to 70% excellent quality protein. of the reactant.38,39 The KCC-1-based sorbents may have several
advantages over conventional silica-based sorbents, including
(i) high catalyst loading, (ii) minimum reduction in surface area
after functionalization and (iii) more accessibility of the catalyst
sites to enhance the reaction, due to the fibrous structure and
highly accessible surface area of KCC-1. Given our continued
interest in nanocatalysis and catalyst development for organic
reactions,40–48 we reported the preparation and characterization
a Young Researchers and Elite Club, Neyshabur Branch, Islamic Azad University,
Neyshabur, Iran. E-mail: seyedmohsen.sadeghzadeh@gmail.com
b The Institute of Pharmaceutical Sciences (TIPS), Tehran University of
Medical Sciences, Tehran 1417614411, Iran
c Department of Pharmaceutical Biomaterials, Faculty of Pharmacy,
Tehran University of Medical Sciences, Tehran, Iran
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018
New J. Chem.

View Article Online
Paper
NJC
above suspension. The reaction was continued for about 24 h
at room temperature. During this period, the pH value was adjusted
by NaOH and kept in the range 12 r pH r 13. The black Fe3O4
NPs were then rinsed several times with ionized water.
General procedure for the preparation of Fe3O4/SiO2 MNPs
0.02 mol of Fe3O4 MNPs were dispersed in a mixture of 80 mL
of ethanol, 20 mL of deionized water and 2.0 mL of 28 wt%
concentrated ammonia aqueous solution (NH3ÁH2O), followed
by the addition of 0.20 g of tetraethyl orthosilicate (TEOS). After
vigorous stirring for 24 h, the final suspension was repeatedly
washed, filtered several times and dried at 60 1C in air.
Scheme 1 Synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine in the
presence of Fe3O4/KCC-1/IG MNPs.
of novel ionic gelation (IG) of sodium tripolyphosphate (TPP) and
spirulina supported on Fe3O4/KCC-1 magnetic nanoparticles.
In addition, we described its utility for N-[(2-hydroxyethoxy)-
carbonyl]glycine synthesis from CO2, ethylene oxide, and a-amino
acids, and it could be easily separated from the reaction mixture for
reuse (Scheme 1).
General procedure for the preparation of Fe3O4/SiO2/KCC-1
MNPs
Fe3O4/SiO2 (0.25 g) was dispersed in an aqueous solution (30 mL)
containing urea (0.3 g) to form solution A under ultrasonication
for 1 h. Cetylpyridinium bromide (CPB) (0.5 g) was added
to 0.75 mL of n-pentanol and 30 mL cyclohexane to form
solution B. Solution A was added to solution B under stirring
at room temperature. Then 1.25 g TEOS was added drop wise
to the abovementioned solution. The resulting mixture was
continually stirred for 1 h at room temperature and then placed
in a 120 1C environment for 5 h, thus initiating the reaction. After
the reaction was completed, the mixture was allowed to cool to
room temperature, and the Fe3O4/SiO2/KCC-1 core–shell micro-
spheres were isolated by strong magnetic suction, then washed
with deionized water and acetone, and dried overnight in a drying
oven at 40 1C. This material was then calcined at 550 1C for
5 h in air.
Experimental
Materials and methods
Chemical materials were purchased from Fluka and Merck in
high purity. Melting points were determined in open capillaries
using an Electrothermal 9100 apparatus and are uncorrected.
FTIR spectra were recorded on a VERTEX 70 spectrometer
(Bruker) in the transmission mode in spectroscopic grade KBr
pellets for all the powders. The nitrogen adsorption/desorption
isotherms were measured at liquid nitrogen temperature
(À196 1C) using a PHS-1020 (PHSCHINA) instrument. The
particle size and structure of the nano particles was observed
by a TESCAN MIRA field emission scanning electron micro-
scope (FE-SEM) with a gold coating and high-resolution trans-
mission electron microscopy (HRTEM) was performed on a
Philips CN120 device. Powder X-ray diffraction data were
obtained using a Bruker D8 Advance model with Cu Ka radia-
tion. Thermogravimetric analysis (TGA) was carried out on a
NETZSCH STA449F3 at a heating rate of 10 1C minÀ1 under
nitrogen. 1H and 13C NMR spectra were recorded on a BRUKER
DRX-300 AVANCE spectrometer at 300.13 and 75.46 MHz, and
a BRUKER DRX-400 AVANCE spectrometer at 400.22 and
100.63 MHz, respectively. Elemental analyses for C, H, and N
were performed using a Heraeus CHN–O-rapid analyzer. The
purity determination of the products and reaction monitoring
were accomplished by TLC on silica gel polygram SILG/UV 254
plates. Mass spectra were recorded on a Shimadzu GCMS-QP5050
Mass Spectrometer.
General procedure for the preparation of Fe3O4/KCC-1/IG MNPs
Fe3O4/KCC-1 (50 mg) was dispersed in acetic acid solution by
ultrasonication for 1 min. Spirulina (125 mg) was dissolved in
the same acetic acid solution and stirred at room temperature
for 1 h. TPP solution (10 mL) was injected dropwise into the
chitosan solution using a syringe pump with a 1 mL minÀ1 rate
of injection. After complete addition of TPP, the mixture was
kept stirring mechanically (1000 rpm) for 1 h. The formed
product was collected with an external magnet and washed
with water until pH 7 and dried under vacuum at room
temperature for 24 h.
General procedure for synthesis of N-[(2-hydroxyethoxy)carbonyl]-
glycine
1.0 MPa of CO2, 1.0 mmol of a-amino acid, 1.0 mmol of
ethylene oxide, and 10 mg of Fe3O4/KCC-1/IG MNPs were
properly added at room temperature. Then, to keep a constant
pressure of 2.0 MPa, CO2 was added from a reservoir tank and
General procedure for the preparation of Fe3O4 MNPs
The synthesis procedure is illustrated as follows: (1) 0.01 mol the temperature was increased to 100 1C. The remaining CO2
FeCl2Á4H2O and 0.03 mol FeCl3Á6H2O were dissolved in 200 mL was slowly removed and the catalyst was segregated through
distilled water, followed by the addition of polyethylene glycol filtration under vacuum after the reaction to be further used for
(PEG) (1.0 g, MW 6000). (2) Sodium hydroxide (NaOH) was the recycling experiments. After drying the resultant crude
added to this solution and the pH value was controlled in the product over anhydrous sodium sulphate, the mixture was
range 12 r pH r 13. (3) Different amounts of hydrazine subjected to column chromatography (CC) using a system of
hydrate (N2H4ÁH2O, 80% concentration) were added to the petroleum ether/EtOAc as an eluent (6 : 1) on silica gel.
New J. Chem.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018

View Article Online
NJC
Paper
Results and discussion
The Fe3O4/KCC-1 core–shell was synthesized by a simple method
and then functionalized by the ionic gelation (IG) of sodium
tripolyphosphate (TPP) and spirulina, according to Scheme 2.
The synthesized Fe3O4/KCC-1/IG MNPs were then characterized
by different methods such as TEM, FESEM, VSM, FT-IR, TGA,
and BET (Scheme 2).
The morphology and structure of the Fe3O4/KCC-1, Fe3O4/
SiO2/IG, and Fe3O4/KCC-1/IG MNPs are further characterized by
TEM and FE-SEM. As shown in Fig. 1f, the Fe3O4/KCC-1
possesses a core of Fe3O4 particles, a nonporous silica layer and
silica fibres. The as-prepared magnetic core–shell fibrous silica
material Fe3O4/KCC-1 with a fibrous structure was uniform and
monodispersed. Also, TEM and FE-SEM images of the highly
textured Fe3O4/KCC-1 samples show that the samples have spheres
of uniform size with diameters of B300 nm and a wrinkled radial
structure (Fig. 1a and f). A close inspection of these images shows
that wrinkled fibers (with thicknesses of B8.5 nm) grow out from
the center of the spheres and are arranged radially in three
dimensions. Also, the overlapping of the wrinkled radial structures
forms cone-shaped open pores. The TEM and FE-SEM images
show that the entire sphere is solid and composed of fibers.
Furthermore, these open hierarchical channel structures and
fibers make the mass transfer of reactants easier and increase
the accessibility of active sites. The FE-SEM and TEM images of
Fe3O4/KCC-1/IG MNPs showed that after modification the
morphology of Fe3O4/KCC-1 is not changed (Fig. 1b and g).
To assess the exact impact of the presence of KCC-1 in the
catalyst, the Fe3O4/KCC-1/IG was compared with Fe3O4/SiO2/IG
MNPs. To further understand this issue, FE-SEM and TEM images of
the used catalyst were compared with those of the fresh catalyst. This
comparison of the FE-SEM and TEM images of the used catalyst with
those of the fresh catalyst showed that the morphologies and
structures of Fe3O4/KCC-1/IG (Fig. 1d and i) and Fe3O4/SiO2/IG MNPs
remained intact after ten recoveries (Fig. 1e and j). Fig. 1e and j show
the degradation of the structure of the Fe3O4/SiO2/IG MNPs in
the reuse process. Their structure has been destroyed. But, the
functionalization of the Fe3O4/KCC-1/IG MNPs does not result in
the change of the morphology (Fig. 1c and h). This study proves
that the stability of the structure of Fe3O4/KCC-1/IG MNPs was
due to the presence of KCC-1 in the catalyst structure. KCC-1 can
be a strong scaffold in ionic gelation structures.
The powder X-ray diffraction patterns of Fe3O4, Fe3O4/KCC-1,
and Fe3O4/KCC-1/IG MNPs are shown in Fig. 2. As can be observed,
Fig. 1 FE-SEM images of Fe3O4/KCC-1 MNPs (a); fresh Fe3O4/KCC-1/IG
MNPs (b); Fe3O4/KCC-1/IG MNPs after ten reuses (c); fresh Fe3O4/SiO2/IG
MNPs (d); Fe3O4/SiO2/IG MNPs after ten reuses (e); TEM images of Fe3O4/
KCC-1 MNPs (f); fresh Fe3O4/KCC-1/IG MNPs (g); Fe3O4/KCC-1/IG MNPs
after ten reuses (h); fresh Fe3O4/SiO2/IG MNPs (i); Fe3O4/SiO2/IG MNPs
after ten reuses (j).
Scheme 2 Schematic illustration of the synthesis for Fe3O4/KCC-1/IG
MNPs.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018
New J. Chem.

View Article Online
Paper
NJC
Fig. 4 Room-temperature magnetization curves of the nano catalysts.
curves of the obtained nanocomposite registered at 300 K show
that nearly no residual magnetism is detected (Fig. 4), which means
that the nanocomposite exhibited paramagnetic characteristics.
Magnetic measurement shows that pure Fe3O4, Fe3O4/KCC-1, and
Fe3O4/KCC-1/IG MNPs have saturation magnetization values of
55.3, 42.9 and 17.2 emu/g respectively. These nanocomposites
with paramagnetic characteristics and high magnetization values
can quickly respond to the external magnetic field and quickly
redisperse once the external magnetic field is removed. The result
reveals that the nanocomposites exhibit good magnetic response,
which suggests a potential application for targeting and separation.
The N2 adsorption–desorption isotherms of Fe3O4/KCC-1/IG
MNPs showed characteristic type IV curves (Fig. 5), which is
consistent with the literature reports on standard fibrous silica
spheres. As for Fe3O4/KCC-1, the BET surface area, total pore
Fig. 2 XRD analysis of (a) Fe3O4, (b) Fe3O4/KCC-1, and (c) Fe3O4/KCC-1/
IG MNPs.
all samples possess the typical diffraction peaks at (220), (311),
(400), (422), (511) and (440), which are in good agreement with the
data for a standard Fe3O4 sample, as reported in the JCPDS card
(No. 19-0629) (Fig. 2a). Besides the peak of iron oxide, the XRD
pattern of Fe3O4/KCC-1 core-shell nanoparticles presented a broad
featureless XRD peak at low diffraction angle, which corresponded
to amorphous silica (Fig. 2b). Fig. 2c shows a typical XRD pattern of
the Fe3O4/KCC-1/IG MNPs. There was no change in it.
The thermal behavior of Fe3O4/KCC-1/IG MNPs is shown in
Fig. 3. The weight loss below 150 1C was ascribed to the
elimination of the physisorbed and chemisorbed solvent on
the surface of both the Fe3O4/KCC-1 and Fe3O4/KCC-1/IG MNPs
materials. In the second stage (180–350 1C), the weight loss is
about 13.4 wt%, which can be attributed to the organic group
derivatives. TGA strongly supported the successful grafting of
organoamine groups on the silica nanospheres as no weight
loss was observed in the range of 150–500 1C for Fe3O4/KCC-1.
The magnetic properties of the nanoparticles were characterized
using a vibrating sample magnetometer (VSM). The magnetization
volume, and BJH pore diameter are obtained as 427 m2 gÀ1
,
1.23 cm3 gÀ1 and 14.51 nm respectively, whereas the corresponding
parameters of the Fe3O4/KCC-1/IG MNPs have decreased to
172 m2 gÀ1, 0.85 cm3 gÀ1, and 10.03 nm. The nitrogen sorption
analysis of Fe3O4/KCC-1/IG MNPs also confirms a regular and
uniform mesostructure with a decrease in surface area, pore
diameter and pore volume parameters in comparison with
that of pristine Fe3O4/KCC-1 MNPs. This could be ascribed to
Fig. 3 TGA diagram of (a) Fe3O4/KCC-1, and (b) Fe3O4/KCC-1/IG MNPs.
Fig. 5 Adsorption–desorption isotherms of Fe3O4/KCC-1/IG MNPs.
New J. Chem.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018

View Article Online
NJC
Paper
Table 1 Structural parameters of Fe3O4/KCC-1 and Fe3O4/KCC-1/IG
MNP materials determined from nitrogen sorption experiments
Table 2 Influence of different catalysts for the synthesis of N-[(2-hydroxy-
ethoxy)carbonyl]glycinea
Catalysts
SBET (m2
g
À1) Va (cm3
g
À1) DBJH (nm) Entry
Catalyst
Yieldb (%)
Fe3O4/KCC-1
Fe3O4/KCC-1/IG
Fe3O4/KCC-1/IG after ten reuses 179
427
172
1.23
0.85
0.89
14.51
10.03
10.21
1
2
3
4
5
Fe3O4/KCC-1
—
—
—
97
48
Fe3O4/KCC-1/TPP
Fe3O4/KCC-1/spirulina
Fe3O4/KCC-1/IG
Fe3O4/SiO2/IG
a
increased loading with the sensing probe, which occupies a
large volume inside the silica spheres (Fig. 5 and Table 1).
Comparison of the BET surface area, total pore volume, and
BJH pore diameter of the used catalyst with those of the fresh
catalyst showed that the structure of the catalyst remained
intact after ten recoveries.
Reaction conditions: appropriate CO2 (1.0 MPa), a-amino acid (1.0 mmol),
ethylene oxide (1.0 mmol), Fe3O4/KCC-1/IG MNPs (10 mg), and CO2
1.0 MPa, at 100 1C. b Isolated yield.
ÀPQO stretching vibration indicating the presence of phos-
phate groups.
FT-IR spectroscopy was employed to determine the surface
modification of the synthesized catalyst (Fig. 6). The symmetric
and asymmetric stretching vibrations of Si–O–Si and the
stretching vibration of O–H at 799, 1088, and 3394 cmÀ1 were
observed for Fe3O4/KCC-1, respectively (Fig. 6a). The FT-IR
analyses of Fe3O4/KCC-1/IG represent the following functional
groups. The FT-IR shows a frequency range from 3400–3300 cmÀ1
representing the O–H stretching vibration. It shows the presence
of carbohydrate and amino acid. The peaks in the frequency
range of 3500–3300 cmÀ1 represent the N–H stretching vibration,
the presence of amines in proteins, and lipids. The bands
observed at 2972 and 2896 cmÀ1 are assigned to C–H stretching
of aliphatic moieties. The peak that appeared at 1720 cmÀ1 is
due to the stretching of the CQO group in the ester and amino acid.
The following peak at 1642 cmÀ1 is attributed to the bending
vibration of the N–H group present in the carbonyl b unsaturated
ketone amide. The peak appearing at 1411 cmÀ1 peak is the CH2
bending vibration. The bands observed at 1342 cmÀ1 and 1278 cmÀ1
due to C–O stretching, O–H bending vibration, respectively,
show the presence of alcohol. On functionalization with the
tripolyphosphate, the intensity of the peak around 1048 cmÀ1
increased and a new peak appeared at 882 cmÀ1 which is
For further investigation on the efficiency of the catalyst in
this reaction, different control experiments were performed and
the obtained data are shown in Table 2. Initially, a standard
reaction was carried out using Fe3O4/KCC-1 showing that no
amount of the desired product was formed after 2 h of reaction
time (Table 2, entry 1). Also, when Fe3O4/KCC-1/TPP was used as
the catalyst, a reaction was not observed (Table 2, entry 2). The
TPP could not give satisfactory catalytic activity under mild
conditions. Based on these disappointing results, we continued
the studies to improve the yield of the product by replacing the
spirulina. The synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine
was not observed when the reaction was carried out using Fe3O4/
KCC-1/TPP and Fe3O4/KCC-1/spirulina MNPs as catalysts. These
results show that the spirulina and TPP do not have a catalytic
role individually (Table 2, entries 2 and 3). These observations
show that the reaction cycle is mainly catalyzed by spirulina and
TPP as simultaneous species supports on the Fe3O4/KCC-1/IG
nanostructure (Table 2, entry 4). As a result, Fe3O4/KCC-1/IG
MNPs were used in the subsequent investigations because of
their high reactivity, high selectivity and easy separation. Also, the
activity and selectivity of the nano-catalyst can be manipulated by
tailoring the chemical and physical properties in terms of size,
shape, composition and morphology. To assess the exact impact of
the presence of KCC-1 in the catalyst, the Fe3O4/KCC-1/IG MNPs
were compared with Fe3O4/SiO2/IG MNPs. To check this, we looked
at Fe3O4/SiO2/IG and Fe3O4/KCC-1/IG MNPs, which have the same
compositions and different structures. When Fe3O4/SiO2/IG was
used as the catalyst, the yield of the desired product was fair to
average, but the yield for Fe3O4/KCC-1/IG MNPs was excellent
(Table 2, entries 4 and 5). Fe3O4/KCC-1/IG MNPs have Lewis acidic
relevant to phosphate and phosphoramide groups, and it
5À
suggests reaction between –P3O10
and –NH3+. The main
differences in the IR spectra is the additional peak in the TPP
bead spectrum at 1150 cmÀ1, which can be assigned to the
(–NH3 ) and Lewis basic (ÀOHÀ) sites, simultaneously. This struc-
+
ture results in high activity of the catalyst.
The reaction conditions were optimized by a-amino acid,
ethylene oxide, and carbon dioxide application for N-[(2-hydroxy-
ethoxy)carbonyl]glycine synthesis catalyzed by Fe3O4/KCC-1/IG MNPs
in this model system. The model reaction provided examinations of
the effects of different parameters like solvent (Table 3). Various
solvents were applied to study their impacts on the synthesis of
Fe3O4/KCC-1/IG MNPs (Table 3, entries 1–15). The obtained
results demonstrated no formation of the expected product
with polar protic solvents, including water, ethanol, methanol,
and isopropanol. The cross-coupling product showed a relatively
Fig. 6 FTIR spectra of (a) Fe3O4/KCC-1 MNPs, and (b) Fe3O4/KCC-1/IG
MNPs.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018
New J. Chem.

View Article Online
Paper
NJC
Table 3 Synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine by Fe3O4/
KCC-1/IG MNPs in different solventsa
Entry
Solvent
Yieldb (%)
1
2
3
4
5
6
7
8
EtOH
H2O
MeOH
i-PrOH
THF
CH2Cl2
EtOAc
DMF
CH3CN
CHCl3
DMSO
Anisole
n-Hexane
Cyclohexane
CCl4
—
—
—
—
35
34
46
31
39
37
43
52
—
—
—
97
9
10
11
12
13
14
15
16
Fig. 8 Effect of temperature on the yield of N-[(2-hydroxyethoxy)carbonyl]-
glycine.
Solvent-free
notable influence on the activity of the catalyst. The reality that
high temperature is useful to the N-[(2-hydroxyethoxy)carbonyl]-
glycine production illustrates that the coupling reactions are
thermodynamically desirable.50–52 With the increase of temperature
from 40 1C to 130 1C, the N-[(2-hydroxyethoxy)carbonyl]glycine yields
significantly rose from 10% to 97%; thus high temperature is useful
to the coupling reaction. However, it is widely reported that the
cycloaddition reactions of CO2 with ethylene oxide are typically
exothermic processes, so in the viewpoint of its thermodynamic
equilibrium, higher temperatures may contain the cyclic carbonate
formation.53,54 Furthermore, higher temperatures are liable to lead
to the polymerization of the N-[(2-hydroxyethoxy)carbonyl]glycine,
and therefore worsen the catalytic productivity.55 Considering the
above results and high conversion of 97%, experiments of higher
temperature were not carried out and 100 1C was adopted as the
optimal reaction temperature.
Also, to optimize the yield of N-[(2-hydroxyethoxy)carbonyl]-
glycine and evaluate the catalytic performances of our Fe3O4/
KCC-1/IG MNPs, the effect of CO2 pressure was investigated.
The cycloaddition reaction between a-amino acid, ethylene oxide,
and carbon dioxide catalyzed by Fe3O4/KCC-1/IG MNPs was
examined systematically as a model reaction system (Fig. 9).
Since the diffusion may affect the kinetics of reactions in the mass
transfer accompanied by the reaction between a-amino acid,
ethylene oxide, and carbon dioxide, an optimum CO2 pressure
range for the maximum yield of Fe3O4/KCC-1/IG MNPs must exist.
a
Reaction conditions: appropriate a-amino acid (1.0 mmol), ethylene
oxide (1.0 mmol), Fe3O4/KCC-1/IG MNPs (10 mg), solvent (10 mL), and
CO2 2.0 MPa, at 100 1C. Isolated yields.
b
average yield with DMF, EtOAc, and DMSO as polar aprotic solvents.
In this research, solvents were found to have less efficiency
than conventional heating under solvent-free conditions
(Table 3, entry 16). When the reaction was conducted in less
polar solvents, such as anisole or toluene, the average yields of
the carbonylative cross-coupling product were isolated, while a
low yield was obtained in polar solvents.
The N-[(2-hydroxyethoxy)carbonyl]glycine yield versus reaction
time was depicted in Fig. 7. N-[(2-hydroxyethoxy)carbonyl]glycine
yield increased quickly with increasing reaction time before
30 min. The increasing trend slowed down and the highest
transformation was obtained at 40 min. Protracted reactions
beyond 40 min resulted in the reduction of N-[(2-hydroxyethoxy)-
carbonyl]glycine yields. It looks that the formed N-[(2-hydroxy-
ethoxy)carbonyl]glycine enhanced the viscosity of the reaction
system to obstruct the interplay between the catalyst and reac-
tants at longer reaction times.49 Thus, 40 min was established as
the optimum reaction time.
Fig. 8 illustrates the dependence of the N-[(2-hydroxyethoxy)-
carbonyl]glycine yield on temperature at 1 MPa, 40 min and
40–130 1C. It is revealed that the reaction temperature has a
Fig. 7 Effect of time on the yield of N-[(2-hydroxyethoxy)carbonyl]-
Fig. 9 Effect of CO2 pressure on the synthesis of N-[(2-hydroxyethoxy)-
glycine.
carbonyl]glycine.
New J. Chem.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018

View Article Online
NJC
Paper
The pressure effect investigation was carried out in the range of
0.5–5.0 MPa. As shown in Fig. 9, the Fe3O4/KCC-1/IG MNP yield
increased sharply when the CO2 pressure increased from
0.5 to 1.0 MPa, and then stabilized at CO2 pressure ranges of
1.0–2.0 MPa. Nevertheless, a reduced yield was obtained as
soon as the pressure reached 3.0 MPa. Based on their reports, it
could be explained that in the low-pressure region, higher CO2
pressure could increase the CO2 concentration in the reaction
system to enhance the yield; however, too high CO2 pressure
would decrease the ethylene oxide concentration in the vicinity
of the catalyst to lower the N-[(2-hydroxyethoxy)carbonyl]glycine
yield, and a lower ethylene oxide concentration is unfavorable
to the reaction because ethylene oxide is also a reactant.56,57
The competition between these opposite factor gave rise to an
optimal pressure of 1.0 MPa for the best N-[(2-hydroxyethoxy)-
carbonyl]glycine yields.
With the optimized conditions in hand, propylene oxide
could also be employed to synthesize N-[(2-hydroxyethoxy)-
carbonyl]glycine in high yields (Table 4, entry 1). Furthermore,
we were interested to study the generality of the transformation
with different amines. With the use of the combination of
Fe3O4/KCC-1/IG MNPs as catalysts at 100 1C in 40 min, different
amine nucleophiles could be converted to the corresponding
N-aryl carbamates in good to excellent yields. When anilines
were used, good to excellent yields were obtained. A variety of
Fig. 10 The reusability of the catalysts for the synthesis of N-[(2-hydroxy-
ethoxy)carbonyl]glycine.
functional groups are tolerated in this procedure, including
electron-donating and, remarkably, even electron-withdrawing
groups such as –F, –I, and –CN (Table 4, entries 3–5). We discovered
a relatively high yield of the product to occur in the reactions with
electron-donating groups. For example, –CH3, and –OC2H5 produced
N-aryl carbamate yields of 98%, and 94%, respectively (Table 4,
entries 6 and 7). As shown in Table 4, various electron-donating and
electron-withdrawing groups give the desired products with appreci-
able yields. In contrast, a dramatic effect is observed in the case of
aliphatic amines. Also, an exciting effect is observed in the case of
aliphatic amines under similar reaction conditions in good yields
(Table 4, entries 8–11).
The reusability of the Fe3O4/KCC-1/IG MNP catalyst was also
investigated. It was observed that it can be reused for up to ten
runs without much loss in its catalytic activity, an essential
aspect of green chemistry. The reusability of the Fe3O4/KCC-1/
IG MNP catalyst upon ten consecutive runs, was also investi-
gated in the synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine
under the optimized conditions. The catalyst could be recycled
easily followed by washing several times with ethanol. It was
then dried at room temperature and was recycled ten consecutive
times with almost unaltered catalytic activity (Fig. 10).
Table 4 Synthesis of products of various amines with propylene oxide,
CO2 in the presence of the Fe3O4/KCC-1/IG MNPsa
Entry
1
Amine
Product ratio 1 : 2
40 : 60
Yieldb (%)
89
2
3
4
5
6
7
8
9
35 : 65
40 : 60
42 : 58
35 : 65
40 : 60
50 : 50
45 : 55
45 : 55
86
94
74
68
98
94
75
89
Conclusions
In the present study Fe3O4/KCC-1/IG MNPs was synthesized
and characterized as an environmentally-friendly nanocatalyst
for the synthesis of N-[(2-hydroxyethoxy)carbonyl]glycine from
carbon dioxide, ethylene oxide, and a-amino acid. The experi-
mental results displayed the core–shell structure of the synthesized
catalyst with a mean size range of 250–300 nm. In addition, the
catalyst was easily recoverable and reusable. Subsequently, high
yields in short reaction times were achieved without the need for an
expensive catalyst as well as excellent reusability for at least ten runs
in the corresponding reaction without a reduction in catalytic
activity.
10
40 : 60
45 : 55
90
94
11
a
Conflicts of interest
Reaction conditions: appropriate CO2 (1.0 MPa), amines (1.0 mmol),
propylene oxide (1.0 mmol), Fe3O4/KCC-1/IG MNPs (10 mg), and CO2
b
There are no conflicts to declare.
1.0 MPa, at 100 1C. Isolated yield.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018
New J. Chem.

View Article Online
Paper
NJC
29 D. Akin, A. Yakar and U. Gu¨ndu¨z, Water Environ. Res., 2015,
87, 425–436.
Notes and references
1 M. North, R. Pasquale and C. Young, Green Chem., 2010, 12,
1514–1539.
2 K. Soga, Y. Tazuke, S. Hosoda and S. Ikeda, J. Polym. Sci.,
Polym. Chem. Ed., 1977, 15, 219–229.
3 B. Ochiai and E. T. Prog, Polym. Sci., 2005, 30, 183–215.
4 J. Bayardon, J. Holz, B. Schaffner, V. Andrushko, S. Verevkin,
A. Preetz and A. Borner, Angew. Chem., Int. Ed., 2007, 46,
5971–5974.
5 T. Tsuda, K. Kondo, T. Tomioka, Y. Takahashi, H. Matsumoto,
S. Kuwabata and C. L. Hussey, Angew. Chem., Int. Ed., 2011, 50,
1310–1313.
30 K. H. Liew, M. Rocha, C. Pereira, A. L. Pires, A. M. Pereira,
M. A. Yarmo, J. C. Juan, R. M. Yusop, A. F. Peixoto and
C. Freire, ChemCatChem, 2017, 23, 3930–3941.
31 A. Jain, K. Thakur, G. Sharma, P. Kush and U. K. Jain,
Carbohydr. Polym., 2016, 137, 65–74.
32 V. Polshettiwar, D. Cha, X. Zhang and J. M. Basset, Angew.
Chem., 2010, 49, 9652–9656.
33 A. Maity and V. Polshettiwar, ChemSusChem, 2017, 10,
3866–3913.
34 P. K. Kundu, M. Dhiman, A. Modak, A. Chowdhury and
V. Polshettiwar, ChemPlusChem, 2016, 81, 1142–1146.
35 P. Gautam, M. Dhiman, V. Polshettiwar and B. M. Bhanage,
Green Chem., 2016, 18, 5890–5899.
6 J. Thielen, W. H. Meyer and K. Landfester, Chem. Mater.,
2011, 23, 2120–2129.
7 W. Peppel, J. Ind. Eng. Chem., 1958, 50, 767–770.
8 A. A. A. Shamsuzzaman and B. Khan, Synth. Commun., 2010,
40, 2278–2283.
9 Z. Zhang, F. Fan, H. Xing, Q. Yang, Z. Bao and Q. Ren, ACS
Sustainable Chem. Eng., 2017, 5, 2841–2846.
10 A. A. G. Shaikh and S. Sivaram, Chem. Rev., 1996, 96, 951–976.
11 M. North and R. Pasquale, Angew. Chem., Int. Ed., 2009, 48,
2946–2948.
36 A. Fihri, D. Cha, M. Bouhrara, N. Almana and V. Polshettiwar,
ChemSusChem, 2012, 5, 85–89.
37 A. Fihri, M. Bouhrara, U. Patil, D. Cha, Y. Saih and
V. Polshettiwar, ACS Catal., 2012, 2, 1425–1431.
38 A. S. Lilly Thankamony, C. Lion, F. Pourpoint, B. Singh, A. J.
Perez Linde, D. Carnevale, G. Bodenhausen, H. Vezin, O. Lafon
and V. Polshettiwar, Angew. Chem., 2015, 54, 2190–2193.
39 N. D. Petkovich and A. Stein, Chem. Soc. Rev., 2013, 42,
3721–3739.
12 P. Yan and H. W. Jing, Adv. Synth. Catal., 2009, 351, 1325–1332.
13 L. Jin, Y. Huang, H. Jing, T. Chang and P. Yan, Tetrahedron:
Asymmetry, 2008, 19, 1947–1953.
40 C. M. Parlett, K. Wilson and A. F. Lee, Chem. Soc. Rev., 2013,
42, 3876–3893.
14 R. L. Paddock and S. T. Nguyen, Chem. Commun., 2004, 1622–1623.
15 T. Chang, L. Jin and H. Jing, ChemCatChem, 2009, 1, 379–383.
16 D. J. Darensbourg and R. M. Mackiewicz, J. Am. Chem. Soc.,
2005, 127, 14026–14038.
17 C. Lang, Y. Shuangfeng, L. Wenhua, Z. Yuanyuan, L. Shenglian
and A. Chak-tong, Catal. Lett., 2010, 137, 74–80.
18 A. Baba, T. Nozaki and H. Matsuda, Bull. Chem. Soc. Jpn., 1987,
60, 1552–1554.
19 Y. Tsutsumi, K. Yamakawa, M. Yoshida, T. Ema and T. Sakai,
Org. Lett., 2010, 12, 5728–5731.
20 P. Brignou, M. Priebe Gil, O. Casagrande, J. F. Carpentier
and S. M. Guillaume, Macromolecules, 2010, 43, 8007–8017.
21 D. Tian, B. Liu, Q. Gan, H. Li and D. J. Darensbourg, ACS
Catal., 2012, 2, 2029–2035.
41 S. M. Sadeghzadeh, R. Zhiani, S. Emrani and M. Ghabdian,
RSC Adv., 2017, 7, 50838–50843.
42 S. M. Sadeghzadeh, R. Zhiani, M. Khoobi and S. Emrani,
Microporous Mesoporous Mater., 2018, 257, 147–153.
43 S. M. Sadeghzadeh, Microporous Mesoporous Mater., 2016,
234, 310–316.
44 S. M. Sadeghzadeh, J. Mol. Liq., 2016, 223, 267–273.
45 S. M. Sadeghzadeh, J. Mol. Catal. A: Chem., 2016, 423,
216–223.
46 S. M. Sdeghzadeh, Catal. Sci. Technol., 2016, 6, 1435–1441.
47 S. M. Sadeghzadeh, Catal. Commun., 2015, 72, 91–96.
48 S. M. Sadeghzadeh, Green Chem., 2015, 17, 3059–3066.
49 D. S. Bai, H. W. Jing and G. J. Wang, Appl. Organomet. Chem.,
2012, 26, 600–603.
22 D. J. Coady, H. W. Horn, G. O. Jones, H. Sardon, A. C. Engler,
R. M. Waymouth, J. E. Rice, Y. Y. Yang and J. L. Hedrick, ACS
Macro Lett., 2013, 2, 306–312.
50 R. J. Wei, X. H. Zhang, B. Y. Du, Z. Q. Fan and G. R. Qi, RSC
Adv., 2013, 3, 17307–17313.
51 J. L. Song, B. B. Zhang, P. Zhang, J. Ma, J. L. Liu, H. L. Fan,
T. Jiang and B. X. Han, Catal. Today, 2012, 183, 130–135.
52 W. G. Cheng, Z. Z. Fu, J. Q. Wang, J. Sun and S. J. Zhang,
Synth. Commun., 2012, 42, 2564–2573.
`
23 M. Selva, A. Caretto, M. Noe and A. Perosa, Org. Biomol.
Chem., 2014, 12, 4143–4155.
´
24 P. Olsen, M. Oschmann, E. V. Johnston and B. Åkermark,
Green Chem., 2018, 20, 469–475.
25 A. Vonshak, A. Abeliovich, S. Boussiba, S. Arad and
A. Richmond, Biomass, 1982, 2, 175–185.
53 J. Xu, F. Wu, Q. Jiang and Y. X. Li, Catal. Sci. Technol., 2015,
5, 447–454.
54 J. Xu, F. Wu, Q. Jiang, J. K. Shang and Y. X. Li, J. Mol. Catal.
A: Chem., 2015, 403, 77–83.
´
26 G. Torzillo, P. Bernardini and J. Masojıdek, J. Phycol., 1998,
34, 504–510.
55 L. Han, H. Li, S. J. Choi, M. S. Park, S. M. Lee, Y. J. Kim and
D. W. Park, Appl. Catal., A, 2012, 429, 67–72.
56 Y. Xie, Z. F. Zhang, T. Jiang, J. L. He, B. X. Han, T. B. Wu and
K. L. Ding, Angew. Chem., Int. Ed., 2007, 46, 7255–7258.
27 B. M. E. Chagas, C. Dorado, M. J. Serapiglia, C. A. Mullen, A. A.
´
Boateng, M. A. F. Melo and C. H. Ataıde, Fuel, 2016, 179,
124–134.
28 S. M. Sadeghzadeh, R. Zhiani and S. Emrani, Catal. Lett., 57 L. F. Xiao, F. W. Li, J. J. Peng and C. G. Xia, J. Mol. Catal. A:
2018, 148, 119–124.
Chem., 2006, 253, 265–269.
New J. Chem.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2018