S.S. Bhagade et al.
CatalysisTodayxxx(xxxx)xxx–xxx
Scheme 1. Reductive-hydroformylation of 1-octene.
metal complexes for the reductive-hydroformylation of 1-octene to 1-
nonanol with the dual catalytical system. It is well known that Nano
Co3O4-materials with different morphology is used as a gas sensor [18],
catalyst [19] and in lithium-ion batteries [20]. Similarly, CoO nano-
materials act as an electrode material for electrochemical super capa-
citors [21]. Recently, Yuba ma et al. [22] developed a protocol for one
pot synthesis of tricyclodecanedimethylol (TDDMO) using Co3O4 sup-
ported Au nanoparticles. They showed that there is a formation of Co
(CO)x(PPh)y like catalytically active complex on a Co3O4 surface which
is assisted by Au nanoparticles supported on the surface of Co3O4. They
have limitations like poor regio and chemo selectivity, the use of harsh
reaction conditions, multistep synthetic procedures, the high cost of
phosphine ancillary and difficulties in the recovery of a metal catalyst
from the homogeneous reaction mixture. The applicability of these
systems is not economical at a larger scale and more particularly for
higher olefins. Hence, with our continuous interest in the synthesis gas
application for fine chemical synthesis [23–26], herein, we wish to
report a protocol for hydroformylation-hydrogenation of 1-octene to
nonanol using fine fibrous Co3O4 nano-catalyst in absence of any co-
catalyst or phosphine ligand (Scheme 1). Interestingly, this reaction
was affected by different shape and sizes of Co3O4 nano-materials.
Conversion and the selectivity towards desired product were found to
be influenced by nature of solvent in the reaction medium and synthesis
gas composition.
(Rtx-17, 30 m × 25 mm ID, film thickness(df) = 0.25 μm) (column
flow 2 mL min−1, 70 °C to 240 °C at 10 °C/min rise) was used for the
mass analysis of the products.
2.2. Catalyst preparation
(a) Synthesis of hexagonal Co3O4: 25 mL of distilled water was added
to the 0.5 g of cobalt acetate hexahydrate and 0.25 g of β-cyclo-
dextrin. To the above solution, 1 mL of liquid ammonia (25%) was
added dropwise with continuous stirring, the resulting solution was
then kept for sonication (30 kHz ultrasonic waves at the output
power 5 s on and 5 s off mode) for 15 min. After sonication pre-
cipitate was separated by centrifugation and washed with distilled
water and dried in an oven.
(b) Synthesis of fibrous Co3O4: fibrous shaped cobalt oxide nano-ma-
terial was prepared by using method disclosed by M.M. Durano
et al. [27b] with some minor modification. Typically Cobalt acetate
hexahydrate (0.5 g) and urea (2.0 g) were dissolved in water and
stirred using a magnetic stirrer for 20 min to form a pink color
homogeneous solution. The resultant solution was then transferred
to 100 mL round bottom flask and refluxed for 12 h. After cooling to
room temperature, obtained product was washed with distilled
water and dried at 80 °C. Finally, nano-Co3O4 material was then
prepared by calcinating the resultant product at 400 °C for 4 h.
(c) Synthesis of flake type Co3O4: To 25 mL of distilled water 0.5 g of
cobalt acetate hexahydrate and 0.25 g of β-cyclodextrin were
added. To the above solution 1 mL of ammonia (25%) was added
dropwise with continuous stirring and then kept for sonication for
15 min with the frequency of 60 kHz at the output power 5 s on and
5 s off mode. The resulting precipitate was then subjected to cen-
trifugation and washed with distilled water and dried in an oven.
2. Experimental
2.1. Materials and instruments
All materials were procured from the reputed chemical supplier and
were used without further purification. XRD (X-ray Diffraction) pattern
of synthesized materials were recorded by Shimadzu XRD-6100 using
CuKα-1.54 Å with scanning rate 2 theta (θ) per min and angle ranging
from 20 (θ) to 80 (θ) having current 30 mA and voltage 40 kW. TPR
(Temperature programmed reduction) profile was recorded with the
help of TPDRO 1100 Instrument fitted with TCD(Thermo coupled de-
tector) detector by passing 5% H2 in argon at a rate of 10 °C/min, with
temperature ramp from 30 to 800 °C. The FT-IR(Fourier Transform
Infrared) spectra of synthesize nano-materials were recorded on
Brucker Perkin Elmer-100 spectrometer in the wavelength range from
400 to 4000 cm−1. Tescan MIRA 3 model with secondary electron (SE)
detector were used for FEG-SEM (Field emission gunscanning electron
microscopy) analysis using 10.0 kV. The EDS (Energy dispersive X-ray
spectrum) was recorded on Oxford instrument (model 51-ADD0007).
The yield of synthesized nonanol was confirmed by Perkin Elmer Clarus
400 GC GC (Gas chromatography) equipped with a flame ionization
detector and a capillary column (elite-1, 30 m × 0.32 μm × 0.25 μm).
The formation of product nonanol was confirmed by GC–MS(Gas
Chromatography mass spectrometry). GC–MS-QP 2010 instrument
2.3. General procedure for reductive hydroformylation of 1-octene
In a typical experiment procedure, a 100 mL high-pressure reactor
was charged with 1-octene (15 mmol), Co3O4(4 mol%) and 12 mL of
dry THF. Then the reactor flushed three times with nitrogen to remove
unnecessary gas contains and pressurized to 800 psi by CO/H2 (1:2)
gas. A reactor was then heated to 150 °C for 12 h with a constant stir-
ring speed i.e. 700 rpm. After completion of the reaction time, the
heater was stopped and the reactor was allowed to cool to room tem-
perature. The existing synthesis gas was carefully released. The reaction
mixture was then filtered using filter paper and the crude product was
analyzed by gas chromatography and mass spectrometry [28].
2.4. Recyclability study
The consistent change in conversion and selectivity for product
formation was observed from first to third recycle of nano-material
2