@proceedings { ISI:000291657600151, title = {Ce-Al-MCM-41: an efficient catalyst for Mukaiyama-Michael reaction}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {1161-1166}, publisher = {Elsevier Science BV}, address = {Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, abstract = {

The activity of cerium containing Al-MCM-41 mesoporous materials has been studied for carbon-carbon bond formation reaction like Mukaiyama-Michael reaction under mild liquid phase conditions. The catalysts were synthesized by hydrothermal method at 383 K for 24-36 h in Teflon-lined autoclave and characterized thoroughly by XRD, UV-VIS, TEM, EPR, XPS, (27)Al NMR, NH(3)-TPD, pyridine-IR and AAS in order to obtain well-ordered M41S type materials. The Mukiayama-Michael reactions between silyl enol ether and alpha,beta-unsaturated ketones give Michael product in very good yields (100\% selectivity). The catalysts were reusable.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Kalita, Pranjal and Kumar, Rajiv}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} } @conference { ISI:000291657600157, title = {Chemoselective alkane oxidations by reactive superoxovanadium(V) species in vanadosilicate molecular sieves}, booktitle = {From ZEOLITES to Porous Mof Materials: The 40th Anniversary of International ZEOLITE Conference, Proceedings of The 15th International ZEOLITE Conference}, series = {Studies in Surface Science and Catalysis}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {1205-1212}, publisher = {Elsevier Science BV}, organization = {Elsevier Science BV}, address = {Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, abstract = {

Unlike their titanium analogs, vanadosilicate molecular sieves catalyze the oxidation of the terminal (primary) C-H bonds in paraffins. This dissimilarity is attributed to differences in the type of reactive superoxo species generated on contact with oxidant. The latter were identified and characterized by in situ EPR and DRUV-vis spectroscopic techniques. By a suitable choice of silicate structure (VS-1 or V-MCM-41), solvent and oxidant (H(2)O(2), tert.-butyl hydroperoxide or H(2)+O2()), the V-O bond covalency and mode of O-O bond cleavage in the oxo-species and thereby, the chemoselectivity in the oxidation of the terminal carbon atoms in paraffins could be controlled.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Srinivas, D. and Ratnasamy, P.}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} } @conference { ISI:000291657600254, title = {Ethane bridged hybrid mesoporous silsesquioxanes with sulfonic acid functionalities: synthesis, characterization and catalytic applications}, booktitle = {From Zeolites to Porous Mof Materials: the 40th Anniversary of International Zeolite Conference, Proceedings of the 15th International Zeolite Conference}, series = {Studies in Surface Science and Catalysis}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {1899-1904}, publisher = {Elsevier Science BV}, organization = {Elsevier Science BV}, address = {Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, abstract = {

Periodic mesoporous organosilicas having -CH(2)-CH(2)- groups in the framewall positions and sulfonic acid groups in the pore channels were prepared using 1,2-bis(triethoxysilyl) ethane, 3-mercaptopropyltriethoxysilane and cetyltrimethylammonium surfactant, under basic conditions, by a one-pot synthesis method. XRD, N(2) sorption isotherm and TEM analysis revealed that the mesoporous structural ordering is retained after the functionalization of organic groups while solid-state NMR techniques like (13)C CP MAS NMR and (29)Si MAS NMR show the presence of sulfonic acid groups and the stability of the mesoporous framework with integrated ethane moieties as bridging groups. The hybrid material was more active, selective and stable than the conventional sulfonic acid containing mesoporous catalysts in the Claisen-Schmidt condensation of acetophenone with benzaldehyde to form chalcone.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Shylesh, S. and Samuel, Prinson P. and Parischa, Renu and Singh, A. P.}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} } @conference { ISI:000291657600253, title = {Immobilization of Ntn hydrolases on APTES fuctionalized SBA-15}, booktitle = {From Zeolites to Porous Mof Materials: the 40th Anniversary of International Zeolite Conference, Proceedings of the 15th International Zeolite Conference}, series = {Studies in Surface Science and Catalysis}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {1891-1898}, publisher = {Elsevier Science BV}, organization = {Elsevier Science BV}, address = {Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, abstract = {

APTES Functionalized mesoporous silica SBA-15 molecular sieves have been prepared and used for immobilization of Penicillin G acylase. Physico chemical characterization was done by nitrogen adsorption, powder XRD and TEM methods to understand the nature of immobilized PGA enzyme. XRD data indicate a good mesoscopic order. The characteristic hexagonal features of SBA-15 were maintained in PGA immobilized SBA-15 samples. Incorporation of PGA does not affect the original pore structure of the parent SBA-15. The adsorption of PGA on SBA-15 from buffered solutions with a pH value, 7.8 has been studied as a model protein adsorption system. The maximum activity of the immobilized enzyme was observed at pH 7.8, slightly below the isoelectric point of the enzyme. The loading capacity of immobilized PGA is 34 mg protein per 0.5 g of SBA-15. The stability of Penicillin G acylase was enhanced by the physical entrapment in SBA-15.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Shah, Pallavi and Sridevi, N. and Prabhune, Asmita and Ramaswamy, Veda}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} } @proceedings { ISI:000291657600051, title = {Synthesis and characterization of value added catalysts zeolite beta using environmentally detrimental flyash}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {438-443}, publisher = {Elsevier Science BV}, address = {Beijing, Peoples R China}, abstract = {

Fly ash is a major byproduct of Thermal power plant, which makes a lot of pollution to the environment due to its fineness. When a large amount of fly ash is dumped in the places near to power plants, it mixes in all segment of environment like water, air as well as soil. Though it can be utilized for different useful purposes, due to the lack of technical knowledge about how and proper motivation, no progress has been made in its utilization. It has been demonstrated that the fly ash can be used for making a value added catalyst zeolite beta by using simple and low cost process. In the present paper it is demonstrated that the fly ash can be used as a source of silica and alumina in the synthesis of value added catalyst zeolite beta. Moreover, the influence of different silica sources such as tetraethylortho silicate, silica sol and fumed silica on the physiochemical characteristics of well crystallized zeolite beta was also studied. The detailed characterization was carried out by using powder XRD, (27)Al and (29)Si MAS NMR, chemical analysis and low temperature nitrogen adsorption. Based on the data obtained from various systems containing different silica source, fumed silica is found to be most efficient source materials and showed superiority in the uniformity of aluminum distribution and possesses higher surface area.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Kasture, M. W. and Bokade, Vijay V. and Joshi, P. N. and Kumar, R.}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} }