Synthesis of a Novel Redox Material UDCaT-3: An Efficient and Versatile Catalyst
FULL PAPERS
by using a Siemens D 500 diffractometer. The scattered in-
tensities were collected from 108 to 608 (2q) by scanning at
0.0258 (2q) steps. Surface area, pore volume and pore sizes
were calculated from BETnitrogen adsorption/desorption
isotherms obtained at liquid nitrogen temperature by using
a Micromeritics ASAP 2010 analyser. SEM images were re-
corded with a Cameca SU 30 microscope. FT-IR spectra
were recorded by using Perkin- Elmer Paragon 500 FT-IR
spectrometer.
Liquid-Phase Hydroxylations
The hydroxylation of phenol by hydrogen peroxide was per-
formed in the same reactor, as mentioned before, under
reflux at 608C for 5 h with UDCaT-3(iii) as the catalyst to
G
get dihydroxybenzenes. A reaction mixture of 0.01 mol
phenol and 26 mL methanol, with a catalyst loading of
0.02 gcmÀ3 liquid volume was uniformly stirred. 0.03 mol of
aqueous solution of hydrogen peroxide (30% w/v) was
added by using a peristaltic pump at a constant rate of
0.0017 mmol/s over 5 h. The total volume of aqueous H2O2
added was 3.4 mL. The liquid-phase samples were analyzed
by HPLC (Tosoh) by using an RP C-18 column and UV de-
tector at 280 nm.
Adsorption of Phenol on UDCaT-3(iii)
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In order to ascertain that the organic molecules are chemi-
sorbed on to the surface of the pores of the catalyst, phenol
was chosen as the adsorbate. The adsorption of dilute
phenol from aqueous solution (1000 ppm) was studied by
For the hydroxylation of acetophenone to hydroxyaceto-
phenones, the reaction mixture consisted of 0.01 mol aceto-
phenone, UDCaT-3
(iii) (0.02 gcmÀ3) and 10 mmol of acetic
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using catalyst UDCaT-3
A
acid at 808C. To this 0.05 mol aqueous hydrogen peroxide
(30% w/v) was added using a peristaltic pump, at a rate of
0.0028 mmol/s over 5 h. The analysis was done by gas chro-
matography over a 10% OV-17 (2 m3.2 mm) column.
UDCaT-3(iii) was used with 50 mg phenol in 50 mL water in
ACHTREUNG
an agitated vessel. The experiment was performed in a fully
baffled, 5-cm inner diameter, cylindrical vessel made of
glass (capacity 100 mL, flat bottom). It was equipped with a
standard six-blade pitched turbine impeller of 1.6 cm diame-
ter. The mixture was well agitated at 400 rpm. Samples were
withdrawn periodically from the aqueous solution of phenol
and analyzed by a Chemito 2100 Scanning UV spectropho-
tometer at 271 nm. A calibration curve was prepared. The
decrease in the concentration of phenol was measured and
Hydrogenation
Hydrogenation was carried out in a 100-mL stainless steel
Parr autoclave. The reaction mass consisting of 0.02 mol p-
nitroanisole in s-propanol as solvent (40 mL) and 0.6 g
UDCaT-3(iii) was charged into the autoclave and it was
A
the adsorption isotherm of phenol on UDCaT-3
pared. Adsorption of phenol on UDCaT-3(iii) was further
confirmed by subsequent desorption. UDCaT-3(iii) catalyst
(iii) was pre-
pressurised with hydrogen to 0.5 MPa and agitated. The
pressure inside the autoclave was maintained at 0.5 MPa
throughout the course of the reaction. Clear samples were
withdrawn periodically and analyzed by gas chromatography
over 10% SE-30 on a Chromosorb (2 m3.2 mm) column.
AHCTREUNG
AHCTREUNG
particles were filtered from the aqueous solution, washed
four times with distilled water and subsequently the particles
were mixed with 50 mL methanol. The slurry was sonicated
for 30 min. Sampling was done periodically to monitor the
phenol concentration in methanol. The intensity of the peak
obtained at 271 nm on UV spectrophotometry corresponded
to a 49.5 ppm phenol concentration (2.48 mg in 50 mL). This
also demonstrated that phenol gets chemisorbed on
Identification and Isolation of Products
Product identification in all cases was done by TLC, GC
and GC-MS. The retention times of the reaction products
were also found to match those of the authentic compounds.
UDCaT-3(iii).
U
Liquid-Phase Oxidations
Acknowledgements
The partial oxidation of cinnamyl alcohol and benzyl alcohol
was carried out by using 30% w/v of aqueous hydrogen per-
oxide in the mechanically agitated reactor described earlier.
It was also equipped with a reflux condenser. The assembly
was maintained at 608C. Alcohol (0.0166 mol), PTC
Partial funding was made available through CSIR-NMITLI
project. GDY also acknowledges support from the Darbari
Seth Professor Endowment for a personal chair. He also
thanks the Purdue University for inviting him as Distinguish-
ed Visiting Scholar under their Presidentꢀs Asian Initiative
Program, which allowed him to indulge in creative pursuits.
(0.00167 mol) and UDCaT-3
(iii) (0.02 gcmÀ3) in 1,2-di-
A
chloroethane (20 mL) as solvent was stirred at 1000 rpm.
The required amount of peroxide (0.05 mol, 5.67 mL) was
added using a peristaltic pump, at a rate of 0.021 mmol/s
over 40 min. In the experiment where a solvent mixture was
used as reaction medium, the solvent composition was 30%
acetonitrile (6 mL) and 70% 1,2-dichloroethane (14 mL).
Samples were withdrawn periodically, filtered and analyzed
on a Chemito 8510 gas liquid chromatograph with FID. A
2 m1/8 in stainless steel column, packed with Chromosorb
W loaded with 10% OV-17 (80–100 mesh size) was used.
Synthetic mixtures were used to quantify the data.
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Adv. Synth. Catal. 2008, 350, 2286 – 2294
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