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Dealumination and desilication of synthesized nanoporous MFI samples have been investigated in order to create and modify the acidity of the samples. Desilication of the synthesised samples carried out by treating the samples by an... more
Dealumination and desilication of synthesized nanoporous MFI samples have been investigated in order to create and modify the acidity of the samples. Desilication of the synthesised samples carried out by treating the samples by an alkaline solution leads to an impressive nanoporosity development with increase in the acidic properties, while dealumination of the synthesised samples carried out by treating the samples by an acidic solution mainly modifies the acidity of the synthesised MFI zeolite. The present study shows that application of alkaline and acidic treatments results in modification of the MFI zeolites with independently tailored pore architecture and acidic properties. Such modification enhances the catalytic activity of the samples under different conditions. XRD as well as FT-IR studies have been carried out to characterize the formation of the parent as well as modified MFI zeolite. Specific surface area, pore diameter and pore volume of the samples were studied by N...
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Four samples of MFI zeolites with silica to alumina ratio of 100 and using different silica to carbon mass ratios (1:1, 1:4, 1:8 and 1:12) were synthesized by using carbon black particles. Silica-alumina molar ratio imposes the framework... more
Four samples of MFI zeolites with silica to alumina ratio of 100 and using different silica to carbon mass ratios (1:1, 1:4, 1:8 and 1:12) were synthesized by using carbon black particles. Silica-alumina molar ratio imposes the framework structure to the synthesized zeolites. In general with an increase in the silica-alumina molar gel ratio, the thermal stability, acid resistance and hydrophobicity of the product increases and ion-exchange capacity decreases. A higher molar ratio (as high as 100) of silica to alumina is considered. ZSM-5 zeolites being mainly microporous, their use as catalyst is restricted only to small molecules. So, by introducing mesopores in zeolite framework, we basically tried to overcome the limited use of ZSM-5 in reactions involving large molecules. Pore structure of ZSM-5 can be modified by using carbon black particles during synthesis. Such type of synthesis can be used to introduce the mesopore and to decrease the crystal size of ZSM-5 zeolite. Differen...
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Cobalt-loaded ZSM-5/MCM-41 composites were synthesized and characterized by different characterization techniques and the catalytic activity of the synthesized materials was studied for liquid phase oxidation of diphenylmethane.
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Hierarchical ZSM-5 zeolite with composite micro and mesoporous was obtained by alkali treatment of parent ZSM-5 for 60 min. Vanadia was loaded on modified zeolite by wetness impregnation technique (VDZ). The prepared samples were... more
Hierarchical ZSM-5 zeolite with composite micro and mesoporous was obtained by alkali treatment of parent ZSM-5 for 60 min. Vanadia was loaded on modified zeolite by wetness impregnation technique (VDZ). The prepared samples were characterized by various techniques including XRD, FTIR, TGA, UV-DRS, TEM, XPS and nitrogen adsorption–desorption. Vanadia loaded sample was found to exhibit excellent catalytic activity for the epoxidation of cyclohexene by tertiary butyl hydroperoxide. A controlled reaction was carried out to demonstrate the utility of hierarchical topology of the catalyst. A free radical mechanism was proposed for the reaction with rate constant of 6.91 × 10−2 L mol−1 min−1 and activation energy of 41.81 kJ mol−1. The reaction was carried out without the use of any solvent and the catalytic activity of VDZ was retained even after five runs.
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Aluminosilicates with well-ordered MCM-48 mesostructures were synthesized by one step and two step methods. Single step method was found to be appropriate for metal incorporation. This method was applied to synthesize transition and inner... more
Aluminosilicates with well-ordered MCM-48 mesostructures were synthesized by one step and two step methods. Single step method was found to be appropriate for metal incorporation. This method was applied to synthesize transition and inner transition metal incorporated MCM-48. These modified MCM-48 materials were characterized by a variety of techniques including XRD, FTIR, DRS-UV-Vis, TGA, N2 adsorption and SEM. Post-synthesis modification of the SiMCM-48 material was also done by impregnating 1%, 3% and 5% vanadium without compromising the integrity of the cubic mesostructure. The transition and inner transition metal incorporated MCM-48 materials were tested for oxidation reaction and were found to exhibit far better activities in anisole oxidation than SiMCM-48. Among the metal introduced MCM-48, vanadium–MCM-48 samples showed highest activities.
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Nanocrystalline MFI zeolite was synthesized with a very broad range of silica to alumina ratios using an autoclave for periods of 7 h at 473 K under autogeneous pressure without seeding gel, promoter, organic solvent or sulfuric acid. The... more
Nanocrystalline MFI zeolite was synthesized with a very broad range of silica to alumina ratios using an autoclave for periods of 7 h at 473 K under autogeneous pressure without seeding gel, promoter, organic solvent or sulfuric acid. The procedure has been successfully employed for the synthesis of MFI samples using fumed silica, colloidal silica, aerosil and tetraethylorthosilicate as silica sources. The synthesized samples were characterized by different techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy. Their average crystallite size ranges from about 26 to 55 nm and they exhibit high crystallinity.
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Abstract Ce doped MFI (mobil five) zeolites with different Si to (Ce + Al) and different Ce to Al ratios were synthesized by a hydrothermal synthesis method. All the samples were characterized by different techniques such as X-ray... more
Abstract Ce doped MFI (mobil five) zeolites with different Si to (Ce + Al) and different Ce to Al ratios were synthesized by a hydrothermal synthesis method. All the samples were characterized by different techniques such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV–vis diffuse reflectance spectroscopy (DRS) and scanning electron microscopy (SEM). The results showed that almost pure MFI phase was obtained in all cases with incorporation of cerium metal into the framework. The increase in unit cell parameters observed with an increase in Ce content is indicative of incorporation of Ce into the framework structure of microporous material MFI. Corroboration of the framework incorporation of Ce into the MFI zeolite structure was also obtained from the UV–vis DRS spectra by the presence of an absorption band at 280 nm. TGA and SEM of the samples provide complementary evidence for Ce incorporation into the framework MFI structure.
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... Acetylation of phenol with Al-MCM-41. Krishna G. Bhattacharyya Corresponding Author Contact Information , E-mail The Corresponding Author , a , Anup K. Talukdar a , Parashmani Das a and S. Sivasanker b. ... We express gratitude to Dr.... more
... Acetylation of phenol with Al-MCM-41. Krishna G. Bhattacharyya Corresponding Author Contact Information , E-mail The Corresponding Author , a , Anup K. Talukdar a , Parashmani Das a and S. Sivasanker b. ... We express gratitude to Dr. Paul Ratnasamy, Director of National ...
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Pot culture experiments were conducted to investigate the effect of lime sludge waste on the growth and production of some agricultural crops like mustard (cv. CVM 27), pea (cv. Rashna 30) and rice (cv. Aijong) as well as the... more
Pot culture experiments were conducted to investigate the effect of lime sludge waste on the growth and production of some agricultural crops like mustard (cv. CVM 27), pea (cv. Rashna 30) and rice (cv. Aijong) as well as the physicochemical properties of the ...
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... AK Talukdar et al./Appl. Catal. ... The authors are grateful to Dr. P. Ratnasamy, Deputy Director, NCL, Pune, for permission to use the laboratory facilities. REFERENCES 1 F. Solymosi, Catai. Rev., 1 (1968) 252. 2 K. Othmer,... more
... AK Talukdar et al./Appl. Catal. ... The authors are grateful to Dr. P. Ratnasamy, Deputy Director, NCL, Pune, for permission to use the laboratory facilities. REFERENCES 1 F. Solymosi, Catai. Rev., 1 (1968) 252. 2 K. Othmer, Encyclopedia of Chemical Technology, Vol. ...
Research Interests: Chemical Engineering, Chemistry, High Pressure, Catalysis, Platinum, and 3 morePalladium, Phenol, and Elsevier
... AK Talukdar et al. Applied Catalysis A: General 148 (1997) 357371 371 Acknowledgements The authors are grateful to the Director and Dr. P. Ratnasamy of the National Chemical Laboratory, Pune for allowing the use of the reactor... more
... AK Talukdar et al. Applied Catalysis A: General 148 (1997) 357371 371 Acknowledgements The authors are grateful to the Director and Dr. P. Ratnasamy of the National Chemical Laboratory, Pune for allowing the use of the reactor facility and also to the University Grants ...