Enhanced catalytic activity of cobalt nanoparticles encapsulated with an N-doped porous carbon shell derived from hollow ZIF-8 for efficient synthesis of nitriles from primary alcohols in water

Article abstract of DOI:10.1039/c9gc01893j

A cobalt catalyst derived from a unique core-shell structure based on hollow ZIF-8 and ZIF-67 (ZIF-67@ZIF-8) is prepared, which exhibits excellent catalytic efficiency for the synthesis of nitriles from alcohols in water under mild conditions (1 atm O₂, 50 °C) owing to its large BET surface area, high pore volume, high basicity and hydrophilicity.

Full text of DOI:10.1039/c9gc01893j

View Article Online
View Journal
Green
Chemistry
Cutting-edge research for a greener sustainable future
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: K. Sun, J. sun, G.
Lu and C. Cai, Green Chem., 2019, DOI: 10.1039/C9GC01893J.
Volume 20
This is an Accepted Manuscript, which has been through the
Number
May 2018
Pages 1919-2160
9
7
Royal Society of Chemistry peer review process and has been
accepted for publication.
Green
Chemistry
Cutting-edge research for a greener sustainable future
rsc.li/greenchem
Accepted Manuscripts are published online shortly after 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
Information for Authors.
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 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 1463-9262
PAPER
Paul T. Anastas et al.
The Green ChemisTREE: 20 years after taking root with the 12
principles
rsc.li/greenchem

Please do not adjust margins
Page 1 of 7
Green Chemistry
View Article Online
DOI: 10.1039/C9GC01893J
Journal Name
COMMUNICATION
Enhanced catalytic activity of cobalt nanoparticles encapsulated
with N-doped porous carbon shell derived from hollow ZIF-8 for
efficient synthesis of nitriles from primary alcohols in water
Received 00th January 20xx,
Accepted 00th January 20xx
Kang-kang Sun,a Jia-lin Sun,a Guo-Ping Lu*a and Chun Cai*a
DOI: 10.1039/x0xx00000x
www.rsc.org/
A cobalt catalyst derived from unique core-shell structure based on Nevertheless, these approaches also suffer limits including
hollow ZIF-8 and ZIF-67 (ZIF-67@ZIF-8) is prepared, which exhibits harsh conditions, the use of ligands, non-recyclable catalysts
excellent catalytic efficiency on the synthesis of nitriles from and stoichiometric amounts of strong oxidants.10 Recently,
alcohols in water under mild conditions (1 atm O2, 50oC) owing to Beller and co-works reported a novel strategy for the synthesis
its large BET surface area, high pore volume, high basicity and of nitriles from alcohols. The use of heterogeneous non-noble
hydrophilicity.
metal-based catalysts (Co3O4-NGr/C or Fe2O3-NGr/C) and cheap
regents such as molecular oxygen and aq. NH3 is beneficial to
economic and sustainable.11 Moreover, Gao et al.12 have
Introduction
reported
that
meso-Co-N/C(800)
and
metal-free
heterogeneous catalyst derived from polypyridyl ligand DAA
could be achieved the oxidation of alcohols to nitriles. However,
high temperature and pressure, organic solvents are norm in
these strategies. In terms of atom economy and environmental
friendliness, it is highly desirable to synthesis nitriles from
alcohols by reusable non-noble catalysts in water under mild
conditions using atmospheric pressure O2 as the oxidant.
Nitriles are versatile precursors for preparation of nitrogen-
containing functional compounds and important intermediates
in dyes, pharmaceuticals, natural products, agrochemicals and
various fine chemicals.1 Traditional strategies for the synthesis
of nitriles include the Sandmeyer reaction,2 dehydration of
amide or aldoximes,3 nucleophilic substitution of aryl halides
and transition-metal-catalyzed C-H functionalization of arenes.4
However, these aforementioned methods usually require
multistep processes, high temperature and pressure, toxic HCN
(or metal cyanide), thus producing large amounts of by-
products, which is contrary to the green chemistry perspective.
In recent years, many attempts have been devoted to the
oxidation of aldehydes to nitriles.5 In fact, aldehydes used in
these reaction systems are chemically unstable and usually
prepared by selective oxidation of alcohols,6 so synthesis of
nitriles from alcohols could take a big step towards a sustainable
and economic process.
On the other hand, porous carbon supported Co
nanoparticles derived from ZIF-67 and its derivatives have been
widely used as heterogeneous catalysts for oxidation reaction
due to their extremely high surface areas and large pore
cavities.13 Furthermore, the abundant nitrogen element in ZIFs
exhibits an n-type transport behavior, which results in a higher
positive density, creates a beneficial chemical environment for
O2 adsorption, and improves the conductivity and hydrophilicity
of the material.14 A major obstacle in the carbonization process
is the lack of an efficient method to preserve the morphology of
ZIF-derived porous carbonaceous materials and inhibit the
agglomeration of Co nanoparticles, which greatly reduced their
catalytic activities.15 An reasonable approach is to wrap a
protective layer (such as ZIF-8) on the surface of ZIF-67.13c, 16
Bearing these results in mind,17 we develop a highly efficient
and reusable N-doped Co-based heterogeneous catalyst for
environment friendly synthesis of nitriles from easily available
alcohols. Hollow ZIF-8 is not only the protective shell of ZIF-67,
but also the nitrogen source of carbon material. This work
represents the first example of a recyclable non-noble metal
catalyst for nitriles’ synthesis in water under an atmospheric
pressure of O2 and mild conditions (50oC). The use of O2 and
7
Heterogeneous noble metal catalysts Ru(OH)X/Al2O3 and
Pt/GO8 have been used to achieve this goal. Molecular oxygen,
as a green oxidant, was utilized in these catalytic systems.
Although noble metal catalysts show excellent activity and
selectivity, the high price and limited reserves are not conducive
to large-scale applications. Therefore, some earth-abundant-
metal catalysts have been explored for the synthesis of nitriles.9
a. School of Chemical Engineering, Nanjing University of Science & Technology,
Xiaolingwei 200, Nanjing 210094, P. R. China. E-mail:
glu@njust.edu.cn,c.cai@njust.edu.cn
Electronic Supplementary Information (ESI) available: See DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 2 of 7
COMMUNICATION
Journal Name
under the catalysis of Co-NC derived from BMZIF (entry 8).
water can minimize the waste formation (water is the only
byproduct.), and make the process greener and more
economical. Furthermore, the catalyst can be easily recovered
and reused for six times without an obvious change in yields.
View Article Online
Compared with Co@NC, Cobalt-based mDaOteI:r1ia0.l1s0w39i/tCh9dGiCff0e1r8e9n3Jt
supports afforded much lower yield and selectivity of 2a
(entries 9, 10). These control experiments show that the
synergistic effects between cobalt and C-N composites may play
an important role in the ammoxidation of alcohols to nitriles. In
order to verify the industrial practical value of the catalytic
system, the concentration of 1a increased to 2 M, and a good
isolated yield of 2a (81%) was gained (entry 11) after 24 h.
Results and discussion
Fig. 1 depicts the fabrication process and rough morphology of
Co@NC. After ZIF-67 and Zn2+ were mixed by immersion, 2-
meim was added sequentially. A unique hollow ZIF-8 shell
would be formed around ZIF-67. ZIF-67 act as center core sites
to grow ZIF-8 in this system. First, Zn2+ was immobilized on the
surface of ZIF-67. Epitaxial growth then anchors the formed ZIF-
8 onto the surface of ZIF-67 while also limiting the freedom and
movement of the ZIF-8. Due to growth limitations, the
immobilized ZIF-8 can complete the spontaneous assembly on
the surface of ZIF-67 and then proceed to a crystalline hollow
structure.13c,18
The organic linkers in ZIF-67@ZIF-8 were carbonized
gradually during the slow heating process, and the resulting
carbon-nitrogen composites can prevent the aggregation of Co
nanoparticles. The low boiling point Zn atoms (bp 907oC) could
be evaporated away in the process of calcination, which is
consistent with the ICP-MS result (Table S1).19 The content of
Co in the Co@NC catalysts is 3.4 wt% measured by ICP-MS
(Table S1). For comparison, Co/NC derived from ZIF-67, Co-NC
derived from bimetallic zeolitic imidazolate frameworks
(BMZIFs, based on ZIF-8 and ZIF-67) and Co nanoparticles
supported on typical supporters such as AC (active carbon) and
ZrO2 were also prepared. All these catalytic materials were
performed for the synthesis of nitriles from benzyl alcohols.
Table 1 Optimization of reaction conditions
CN
Catalyst, O2
H2O
OH
Aq.NH3
H2O
1a
2a
Entry
1
2
3
4c
5
6
7
8
9
Catalyst
T(℃)
30
40
50
50
50
50
50
50
50
50
50
Conversionb (%)
Yieldb (%)
Co@NC
Co@NC
Co@NC
Co@NC
-
NC(ZIF-8)
Co/NC
Co-NC
52
76
93
86
0
49
76
93
74
0
0
16
59
0
21
59
5
11
89
Co/AC
Co/ZrO2
Co@NC
3
7
10
11d
85 (81)e
a Reaction conditions: 1a (0.2 mmol), catalyst (4 mol% of Co), 4 equiv. aq. NH3, H2O
(1 mL), 0.1 MPa O2, 12 h. b Conversions and yields were determined by GC (Agilent
c
d
7890A) with nitrobenzene as an internal standard. Air was used instead of O2.
1a (2 mmol), catalyst (4 mol% of Co), H2O (1 mL), 0.1 MPa O2, 50 °C, 24 h. e Isolated
yields.
A series of characterizations of these catalysts were also
performed to elucidate reasons for the significant catalytic
activity of the Co@NC materials. As shown in Fig. 2a, the XRD
patterns of as-synthesized ZIF-67 and ZIF-67@ZIF-8 were
consistent with the simulated XRD patterns of ZIF-8 and ZIF-67,
indicating that the whole synthesis process will not affect the
structure of MOFs. The XRD pattern of the Co/NC displayed two
peaks at around 44.3o and 51.5o, indexed to the characteristic
metal cobalt (111) and (200) diffractions. However, no obvious
peaks for metal cobalt were founded in Co@NC (Fig. 2b). This
may be contributed to the low content and uniform dispersion
of cobalt in Co@NC.20
Fig. 1 Schematic illustration of the synthetic process for Co@NC catalysts.
The aerobic oxidative synthesis of nitriles was performed at a
mild temperature in water using atmospheric pressure O2 as the
oxidant in the absence of base. First, the as-synthesized Co@NC
catalyst was examined for the aerobic oxidation of benzyl
alcohol (1a) in water using aqueous ammonia as the nitrogen
source at 30°C, resulting in a 49% yield of benzonitrile (Table 1,
entry 1). Increasing the reaction temperature could enhance
the yield of benzonitrile obviously (entries 1-3). A blank run
(without any catalyst) failed to yield the desired product (entry
5). No product was formed when the porous carbon catalyst
prepared from ZIF-8 was used (entry 6) indicating that cobalt is
the active sites for the ammoxidation of alcohols. It should be
noted that the reaction also proceeded smoothly under air
atmosphere (entry 4).
As expect, the activity of Co/NC derived from ZIF-67 is quite
low (entry 7), which suggests the importance of ZIF-8 shell for
the activity of catalyst. A moderate yield of 2a was obtained
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 7
Green Chemistry
Please do not adjust margins
Journal Name
COMMUNICATION
View Article Online
DOI: 10.1039/C9GC01893J
Fig. 2 XRD patterns of (a) simulated ZIF-67, as-synthesized ZIF-67, simulated ZIF-8, and
as-synthesized ZIF-67 @ZIF-8; (b) Co/NC and Co@NC;
The morphology and structural analysis of ZIF-67@ZIF-8 and
Co@NC catalysts were characterized by scanning electron
microscopy (SEM) and transmission electron microscopy (TEM).
It can be observed that the ZIF-67 and ZIF-8 in ZIF-67@ZIF-8
sample have a uniform shape. Moreover, ZIF-8 with hollow
structure is wrapped in ZIF-67 (Fig. 3a and Fig. S1). After
calcination under nitrogen atmosphere at 900oC, the resulting
Co@NC retains the morphology of the ZIF precursor except for
the partial shrinkage of the shape (Fig. 3c and Fig. S1c). The Co
nanoparticles in Co@NC are highly dispersed with a standard
deviation (σ) of 1.4 and the average size is 5.9 nm (Fig. 4a). As
comparison, the structure of ZIF-67 is seriously destroyed after
pyrolysis to form Co/NC (Fig. 3b), and the size of cobalt
nanoparticles in Co/NC is large and uneven (Average size: 79.6
nm, σ:39.6) (Fig. 4b).
It is shown that the ZIF-8 shell has a good protective effect on
ZIF-67 during calcination and can effectively prevent the
collapse of ZIF-67 structure, so that Co nanoparticles with
smaller and uniform particles can be obtained. In addition, the
porous carbon shell derived from ZIF-8 is wrapped around the
active cobalt nanoparticles, which not only enhances the
adsorption of reactants, but also prevents the loss of cobalt
nanoparticles in the reaction process, thus promoting the
catalyst recycling effectively.
Fig. 4 TEM images of (a) Co@NC and (b) Co/NC.
The porous character of Co@NC was also investigated by N2
adsorption-desorption isotherms. The N2 adsorption-
desorption isotherms for Co@NC display type-IV hysteresis
loop, characteristic of micro/mesoporous materials (Fig. 5a and
5b). The BET surface areas of Co@NC are 1042 m2 g-1 and the
pore volume is 1.25 cm3 g-1, which is much higher than Co/NC
(80 m2 g-1, 0.21 cm3 g-1) and Co-NC (686 m2 g-1, 0.51 cm3 g-1).21
These results imply that the presence of the hollow ZIF-8 shell
in the synthetic process of Co@NC can greatly increase the
specific surface area and pore volume of the materials. Such
unique porous structure is considered to be of great significance
to the oxygen absorption, transport of the reactant molecules
and exposure of the maximum active sites in the ammoxidation
of alcohols to nitriles.
Fig. 3 SEM images of (a) ZIF-67 @ZIF-8 and (b) Co/NC, TEM image of (c) Co@NC.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 4 of 7
COMMUNICATION
Journal Name
common index to assess the number of defect siteVsieiwnAcraticrlbe oOnnl.in2e4
As we can see, the ID/IG value of Co@NC iDsO1.I:0120,.1w03h9ic/Ch9iGnCd0ic1a89te3Js
that Co@NC have a considerable graphitization degree and
therefore high electronic conductivity.
Fig.
5
(a) Nitrogen adsorption-desorption isotherms of Co@NC and (b) the
corresponding pore size distributions.
X-ray photoelectron spectroscopy (XPS) measurements of
Co@NC shows that there are Co, C, N, and O elements (Fig. S2).
In order to check the chemical state of elements, the XPS
spectra of Co@NC was carefully analyzed. As presented in Fig.
6a, the Co with positions at 796.1 eV with one satellite peak at
803.0 eV can be assigned to Co 2p1/2 of divalent Co. Further
high-resolution XPS analysis of Co 2p3/2 spectra shows that the
Co peaks could be deconvoluted into three peaks at 780.2eV,
782.1 eV, and 786.6 eV, corresponding to Co–O, and Co–Nx and
the satellite peak of Co–O, respectively.13c,22 The appearance of
CoNx can be proved by the N 1s spectra of Co@NC. The N 1s
spectrum in Fig. 6b indicates that five types of nitrogen species
exist in the structure, including pyridinic N (398.4 eV), Co-Nx
(399.1 eV), pyrrolic N (400.3 eV), graphitic N (401.3 eV) and
oxidized N (402.9 eV).22b,23 These results indicate that part of
the Co atoms may have an interaction with the N atoms to form
Co-N sites, which can immobilize cobalt and reduce the
agglomeration of cobalt nanoparticles. In addition, the
percentage of cobalt atoms based on XPS results (0.68%) is less
than ICP results (3.4%). This confirms that cobalt nanoparticles
are encapsulated by porous carbon, thus shielding the Co signal.
Basicity and hydrophilicity are reported to play an important
role in promoting the activity of liquid phase ammoxidation of
alcohols to nitriles in water. The basicity of Co@NC was further
confirmed using CO2-TPD (Fig. 7). The two intense peaks at
200oC and 600oC in the CO2-TPD profile suggest that the Co@NC
possesses both weak and strong Lewis basicity. A much stronger
peak at 200oC observed in the CO2-TPD profile of Co@NC, and
the shift of the peak for strong Lewis basicity to high
temperature, indicates that the dopant of N atoms to form
nitrogen-doped carbon hybrid lead to stronger Lewis basicity.25
In fact, the total amounts of basic sites in Co@NC (3.28 mmol/g)
are higher than that in Co/NC (1.72 mmol/g). The hydrophilicity
was analyzed by the static water contact angles (Fig. S4) and the
results display that the Co@NC has a great hydrophilic (Fig. S5).
Good hydrophilicity is also the key to promote the reaction
operates in water.
Fig. 7 (a) CO2-TPD profiles of Co@NC and Co/NC; (b) their number of basic sites
The above characterization results verify that (1) the
introduction of hollow ZIF-8 is the key to form uniformly
dispersed and smaller Co nanoparticles and carbon material
with high BET surface areas; (2) the porous carbon shell derived
from ZIF-8 is wrapped around the active cobalt nanoparticles;
(3) the ZIF-8 shell enhanced the Lewis basicity and hydrophilicity
of Co@NC. All of these features lead to the Co@NC with
excellent performances for the ammoxidation of alcohols to
nitriles in water.
Fig. 6 XPS spectra of (a) the Co 2p region and (b) the N 1s region.
Raman spectra were used to investigate the carbon structure
in Co@NC (Fig. S3). There are a distinct pair of broad bands
located at 1349 and 1586 cm-1, which can be ascribed to the D-
band (defect) and G-band (graphitic), respectively. The peak
intensity ratio of D-band intensity to G-band intensity is a
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 7
Green Chemistry
Please do not adjust margins
Journal Name
COMMUNICATION
1j
2j
The scope of the ammoxidation of primary alcohols over the
Co@NC materials was next examined and the results are listed
in Table 2. A variety of aromatic alcohols bearing electron-
donating or electron-withdrawing groups afforded the desired
products with good yields. In most cases, benzylic alcohols
containing electro donating groups resulted in good to excellent
yields (Table 2, entries 2-5). When benzylic alcohol substituted
with two or three methoxyl group, 76% and 55% yields of final
products were obtained respectively (entries 6 and 7). In the
cases of benzyl alcohols with electron withdrawing groups, such
as –Cl and -Br, it also achieved moderate yields of the
corresponding nitriles (entries 8 and 9). However, the yields of
2j and 2k were quite low (entries 10 and 11). Probably because
the electron-deficient groups on benzyl alcohol will decrease
the electron density of benzene ring, which can inhibit the
oxidation of benzyl alcohol to benzaldehyde that is the rate
determining step of the reaction.12a It was noteworthy that 1-
naphthylnitrile was obtained in good yields (entry 12).
Furthermore, pyridine and indole derivatives could transform to
the corresponding nitriles (2m-2n) in 99% and 6% yields,
respectively. The oxidation of cinnamyl alcohol in water gave
cinnamonitrile in 70% yield (entry15). We also try to use the
present catalytic system to oxidize the challenging aliphatic
alcohols. Unfortunately, only a small amount of 2p was
obtained due to inactivity of aliphatic alcohols (entry 16).
View Article Online
CN
OH
DOI: 10.1039/C9GC01893J
11
12
13
5
O2N
O2N
1k
2k
OH
CN
88
1l
2l
CN
CN
OH
OH
>99
N
N
1m
2m
14
6
N
N
H
H
1n
2n
CN
OH
15
16
70
3
1o
1p
2o
2p
CN
OH
a
Reaction conditions: alcohols (0.2 mmol), catalyst (4 mol% of Co), 4 equiv. aq.
NH3, Solvent (1 mL), 50oC, 0.1 MPa O2, 12 h. Yields were determined by GC (Agilent
7890A) with nitrobenzene as an internal standard.
Reusability is one of the key factors for heterogeneous
catalysts. In order to investigate the recyclability of the
prepared catalyst, we conducted the reusability experiment for
the Co@NC catalyst in the model reaction. After reaction, the
mixture was extracted with ethyl acetate. Very few aqueous
NH3 flows into the environment after simple extraction. Next,
the solution after extracted, containing Co@NC, was submitted
to another reaction cycle under the same conditions. We can
observe from Fig. 8 that the Co@NC exhibited almost no activity
change after six runs. In addition, ICP-MS analysis confirmed
that the content of cobalt in Co@NC hardly changed after six
cycles (Table S1), indicating that there was no significant
leaching of the active cobalt in the reaction process. We
attribute its robustness to the anchoring effect of N atoms and
the protective effect of the outer porous shell derived from ZIF-
8. These results indicate that Co@NC is highly stable for
ammoxidation of primary alcohols to nitriles under the
optimized conditions.
Table 2 Ammoxidation of various alcohol catalyzed by Co@NC a
Entry
1
Substrate
Nitrile
Yield b (%)
93
CN
OH
1a
1b
1c
2a
2b
2c
CN
CN
OH
OH
OH
2
3
89
78
CN
4
>99
1d
1e
2d
2e
CN
CN
OH
5
6
>99
76
MeO
MeO
MeO
MeO
MeO
MeO
MeO
OH
MeO
MeO
MeO
1f
2f
CN
OH
7
8
55
80
OMe
OMe
2g
1g
CN
OH
OH
Cl
Br
Cl
1h
1i
2h
2i
Fig. 8 Recyclability of Co@NC
Br
CN
9
60
11
E factor is a measure of the waste generated, and organic
solvents are the main contributors to the high values
associated. Lower E factor means higher efficiency and
therefore less pollution to the environment.26 The synthesis of
CN
OH
10
I
I
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 6 of 7
COMMUNICATION
Journal Name
4
5
(a) P. Anbarasan, T. Schareina and M. Beller, CVhieewmArSticolecORnelinve,
2011, 40, 5049-5067. (b) T. Schareina,DAO.I:Z1a0p.1f0a39n/dC9MG.CB01e8ll9e3rJ,
Chem. Commun., 2004, 1388-1389. (c) J. Zanon, A. Klapars and
S. L. Buchwald, J. Am. Chem. Soc., 2003, 125, 2890-2891. (d)
P. Y. Yeung, C. M. So, C. P. Lau and F. Y. Kwong, Org Lett, 2011,
13, 648-651.
(a) K. Murugesan, T. Senthamarai, M. Sohail, M. Sharif, N. V.
Kalevaru and R. V. Jagadeesh, Green Chem., 2018, 20, 266-
273. (b) C. Fang, M. Li, X. Hu, W. Mo, B. Hu, N. Sun, L. Jin and
Z. Shen, RSC Adv., 2017, 7, 1484-1489. (c) Q. Wu, Y. Luo, A. Lei
and J. You, J Am Chem Soc, 2016, 138, 2885-2888. (d) X. Jia, J.
Ma, M. Wang, X. Li, J. Gao and J. Xu, Catal. Sci.Technol., 2016,
6, 7429-7436. (e) B. Xu, Q. Jiang, A. Zhao, J. Jia, Q. Liu, W. Luo
and C. Guo, Chem Commun., 2015, 51, 11264-11267. (f) X. D.
An and S. Yu, Org Lett, 2015, 17, 5064-5067.
(a) J. M. Hoover and S. S. Stahl, J Am Chem Soc, 2011, 133,
16901-16910. (b) Y. Hu, L. Chen and B. Li, Catal. Commun.,
2016, 83, 82-87. (c) C. Bai, A. Li, X. Yao, H. Liu and Y. Li, Green
Chem., 2016, 18, 1061-1069. (d) R. Fang, R. Luque and Y. Li,
Green Chem., 2017, 19, 647-655.
T. Oishi, K. Yamaguchi and N. Mizuno, Angew. Chem. Int Ed.,
2009, 48, 6286-6288.
nitriles was run in an organic-solvent-free medium of water,
which could dramatically lower associated E Factors. An E factor
of 4.9 was determined on the basis of ethyl acetate used for
product extraction, which is much lower than the expected
from the corresponding reaction run in organic solvents.
CN
OH
Co@NC , O2
H2O
Aq.NH3
1a
2a
6
Scheme. 1 E Factor determination.
Conclusions
7
8
9
In summary, we have demonstrated a mild, efficient and
green methodology for the direct conversion of easily available
alcohols to nitriles in water using a novel nitrogen doped
heterogeneous cobalt catalyst (Co@NC) derived from ZIF-
67@ZIF-8. Water is the only by-product in the catalytic process.
The environmentally benign, high efficiency, recyclability (low E
factor) and mild reaction conditions may enhance its potential
in the chemical industry application. Hollow ZIF-8 is both the
protective shell of ZIF-67 and the nitrogen source, thus
improving the surface area, basicity and hydrophilicity of the
carbon material. Furthermore the protective carbon shell
derived from hollow ZIF-8 is considered to be conducive to the
transport and adsorption of substrate and oxygen, as well as to
the effective protection of active cobalt nanoparticles from
leaching.
Y. Preger, T. W. Root and S. S. Stahl, ACS Omega, 2018, 3,
6091-6096.
(a) C. Tao, F. Liu, Y. Zhu, W. Liu and Z. Cao, Org Biomol Chem,
2013, 11, 3349-3354. (b) L. M. Dornan, Q. Cao, J. C. Flanagan,
J. J. Crawford, M. J. Cook and M. J. Muldoon, Chem Commun.,
2013, 49, 6030-6032. (c) S. U. Dighe, D. Chowdhury and S.
Batra, Adv. Synth. Catal., 2014, 356, 3892-3896. (d) T. Ishida,
H. Watanabe, T. Takei, A. Hamasaki, M. Tokunaga and M.
Haruta, Appl. Catal. A-Gen., 2012, 425-426, 85-90. (e) B. V.
Rokade, S. K. Malekar and K. R. Prabhu, Chem. Commun.,
2012, 48, 5506-5508. (f) Q. H. Fan, N. T. Ni, Q. Li, L. H. Zhang
and X. S. Ye, Org. Lett., 2006, 8, 1007-1009.
10 (a) W. Yin, C. Wang, Y. Huang, Org. Lett., 2013, 15, 1850-1853.
(b) D. W. Tan, J. B. Xie, Q. Li, H. X. Li, J. C. Li, H. Y. Li and J. P.
Lang, Dalton Trans, 2014, 43, 14061-14071. (c) Y. Zhang, R.
Huang, B. Gao and J. Zhao, Catal. Lett., 2015, 146, 220-228.
11 R. V. Jagadeesh, H. Junge and M. Beller, Nat Commun., 2014,
5, 4123.
12 (a) S. Shang, L. Wang, W. Dai, B. Chen, Y. Lv and S. Gao, Catal.
Sci. Technol., 2016, 6, 5746-5753. (b) S. Shang, W. Dai, L.
Wang, Y. Lv and S. Gao, Chem. Commun., 2017, 53, 1048-
1051.
Conflicts of interest
There are no conflicts to declare.
13 (a) X. Wang, W. Zhong and Y. Li, Catal. Sci. Technol., 2015, 5,
1014-1020. (b) Y. X. Zhou, Y. Z. Chen, L. Cao, J. Lu and H. L.
Jiang, Chem Commun., 2015, 51, 8292-8295. (c) H. Chen, K.
Shen, Q. Mao, J. Chen and Y. Li, ACS Catal., 2018, 8, 1417-
1426.(d) W. Zhong, H. Liu, C. Bai, S. Liao and Y. Li, ACS Catal.,
2015, 5, 1850-1856.
14 (a) M. Wang, X. Xu, J. Tang, S. Hou, M. S. A. Hossain, L. Pan and
Y. Yamauchi, Chem Commun., 2017, 53, 10784-10787.(b) D.
Xu, Y. Tong, T. Yan, L. Shi and D. Zhang, ACS Sustain. Chem.
Eng., 2017, 5, 5810-5819. (c) S. Yang, L. Peng, P. Huang, X.
Wang, Y. Sun, C. Cao and W. Song, Angew. Chem. Int. Ed.,
2016, 55, 4016-4020. (d) J. Zhang, J. Fang, J. Han, T. Yan, L. Shi
and D. Zhang, J. Mater. Chem. A, 2018, 6, 15245-15252. (e) Y.
Zhao, J. Wan, H. Yao, L. Zhang, K. Lin, L. Wang, N. Yang, D. Liu,
L. Song, J. Zhu, L. Gu, L. Liu, H. Zhao, Y. Li and D. Wang, Nat.
Chem., 2018, 10, 924-931. (f) X. Cui, Y. Li, S. Bachmann, M.
Scalone, A. E. Surkus, K. Junge, C. Topf and M. Beller, J. Am.
Chem. Soc., 2015, 137, 10652-10658.
ACKNOWLEDGEMENTS
We gratefully acknowledge Key Laboratory of Biomass Energy
and Material, Jiangsu Province (JSBEM201912), Chinese
Postdoctoral Science Foundation (2015M571761, 2016T90465)
for financial support. This work was a project funded by the
Priority Academic Program development of Jiangsu Higher
Education Institution.
Notes and references
1
(a) E. Soleimani, M. M. Khodaei, N. Batooie and M.
Baghbanzadeh, Green Chem., 2011, 13, 566-569. (b) J. Yang,
M. R. Karver, W. Li, S. Sahu and N. K. Devaraj, Angew. Chem.
Int. Ed., 2012, 51, 5222-5225. (c) J. S. Miller and J. L. Manson,
Acc. Chem. Res., 2001, 34, 563-570.
15 (a) S. Gadipelli, T. Zhao, S. A. Shevlin and Z. Guo, Energ.
Environ. Sci., 2016, 9, 1661-1667. (b) S. Gadipelli and Z. X. Guo,
ChemSusChem, 2015, 8, 2123-2132.
16 J. Zhao, X. Quan, S. Chen, Y. Liu and H. Yu, ACS Appl. Mater.
Inter., 2017, 9, 28685-28694.
2
3
H. H. Hodgson, Chem. Rev., 1947, 40, 251-277.
(a) J. Kim and S. S. Stahl, ACS Catal., 2013, 3, 1652-1656. (b) S.
Zhou, D. Addis, S. Das, K. Junge and M. Beller, Chem Commun.,
2009, 32, 4883-4885. (c) S. I. Maffioli, E. Marzorati and A.
Marazzi, Org. Lett., 2005, 7, 5237-5239.
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 7
Green Chemistry
Please do not adjust margins
Journal Name
COMMUNICATION
17 (a) K.-k. Sun, S.-j. Chen, Z.-l. Li, G.-p. Lu and C. Cai, Green Chem.,
2019, 21, 1602-1608.
View Article Online
DOI: 10.1039/C9GC01893J
18 (a) L. Feng, J.-L. Li, G. S. Day, X.-L. Lv and H.-C. Zhou, Chem,
2019, 5, 1265-1274. (b) I. Lee, S. Choi, H. J. Lee and M. Oh,
Cryst. Growth Des., 2015, 15, 5169-5173. (c) Y. Liu, Y. Yang, Y.
Sun, J. Song, N. G. Rudawski, X. Chen and W. Tan, J. Am. Chem.
Soc., 2019, 141, 7407-7413. (d) H-G. Yang, H-C. Zeng,. J. Phys.
Chem. B, 2004, 108, 3492–3495.
19 P. Yin, T. Yao, Y. Wu, L. Zheng, Y. Lin, W. Liu, H. Ju, J. Zhu, X.
Hong, Z. Deng, G. Zhou, S. Wei and Y. Li, Angew. Chem. Int.
Ed., 2016, 55, 10800-10805.
20 Y. Wang, S. Sang, W. Zhu, L. Gao and G. Xiao, Chem. Eng. J.,
2016, 299, 104-111.
21 K. K. Sun, S. J. Chen, J. W. Zhang, G. P. Lu and C. Cai,
ChemCatChem, 2019, 11, 1264-1271.
22 (a) Z. Liang, C. Zhang, H. Yuan, W. Zhang, H. Zheng and R. Cao,
Chem. Commun., 2018, 54, 7519-7522. (b) B. Qiu, C. Yang, W.
Guo, Y. Xu, Z. Liang, D. Ma and R. Zou, J Mater Chem A, 2017,
5, 8081-8086. (c) M. Liu, H. Lin, Z. Mei, J. Yang, J. Lin, Y. Liu and
F. Pan, ChemSusChem, 2018, 11, 3631-3639. (d) T. Song, P.
Ren, Y. Duan, Z. Wang, X. Chen and Y. Yang, Green Chem.,
2018, 20, 4629-4637. (e) D. Liu, P. Yang, H. Zhang, M. Liu, W.
Zhang, D. Xu and J. Gao, Green Chem., 2019, 21, 2129-2137.
23 (a) X. Liu, W. Li and S. Zou, J Mater Chem A, 2018, 6, 17067-
17074.
24 M. Liu, L. Gan, W. Xiong, Z. Xu, D. Zhu and L. Chen, J. Mater.
Chem. A, 2014, 2, 2555-2562.
25 J. Li, J. Zhang, S. Wang, G. Xu, H. Wang and D. G. Vlachos, ACS
Catal., 2019, 9, 1564-1577.
26 B. H. Lipshutz, N. A. Isley, J. C. Fennewald and E. D. Slack,
Angew. Chem. Int. Ed., 2013, 52, 10952-10958.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins