@article { ISI:000236923400014, title = {Catalytic transesterification of beta-ketoesters with zeolite H-FER under solvent free conditions}, journal = {Arkivoc}, volume = {13}, number = {13}, year = {2005}, month = {MAY}, pages = {162-168}, publisher = {ARKAT USA INC}, type = {Article}, address = {C/O ALAN R KATRITZKY, UNIV FLORIDA, DEPT CHEMISTRY, PO BOX 117200, GAINESVILLE, FL 32611 USA}, abstract = {

Zeolite H-FER catalyzes the transesterification of beta-ketoesters with variety of alcohols under solvent-less condition in excellent yields. The catalyst can be reused without any loss of activity.

}, keywords = {ferrierite, transesterification, zeolite}, issn = {1424-6376}, author = {Chavan, Subhash P. and Pasupathy, K. and Shengule, S. and Shinde, V. and Anand, R.} } @article { ISI:000236916100016, title = {Green protocol for the synthesis of N-oxides from secondary amines using vanadium silicate molecular sieve catalyst}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {248}, number = {1-2}, year = {2006}, month = {APR }, pages = {109-112}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Vanadium silicate molecular sieve catalyst VS-I was found to promote efficiently the oxidation of alpha alpha,alpha{\textquoteright}alpha{\textquoteright}-tetrasubstituted secondary amines with 30\% aqueous hydrogen peroxide as oxidant. In comparison to other catalysts reported to date, this heterogeneous catalyst offers a remarkably simple workup procedure and is reusable without any appreciable loss of activity. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {heterogeneous catalyst, Hydrogen peroxide, N-oxide, VS-1, zeolite}, issn = {1381-1169}, doi = {10.1016/j.molcata.2005.12.005}, author = {Phukan, P. and Khisti, R. S. and Sudalai, A.} } @article { ISI:000238142900019, title = {Synthesis of beta-amino alcohols from aromatic amines and alkylene carbonates using Na-Y zeolite catalyst}, journal = {Synlett}, number = {9}, year = {2006}, month = {JUN}, pages = {1374-1378}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A simple, efficient, and environmentally benign methodology for the synthesis of beta-amino alcohols from aromatic amines and alkylene carbonates in the presence of the highly active and reusable solid base catalyst Na-Y zeolite is demonstrated.

}, keywords = {Alkylation, alkylene carbonate, Amine, Amino alcohols, zeolite}, issn = {0936-5214}, doi = {10.1055/s-2006-939697}, author = {Shivarkar, Anandkumar B. and Gupte, Sunil P. and Chaudhari, Raghunath V.} } @article { ISI:000239739400010, title = {Synthesis of high alumina ZSM-5 molecular sieve with ethylene diamine as template}, journal = {Journal of the Indian Chemical Society}, volume = {83}, number = {7}, year = {2006}, month = {JUL}, pages = {686-691}, publisher = {INDIAN CHEMICAL SOC}, type = {Article}, address = {92 ACHARYA PRAFULLA CHANDRA RD ATTN:DR INDRAJIT KAR/EXEC SEC, CALCUTTA 700009, INDIA}, abstract = {

Attempts were made to investigate compositional constraints in the synthesis of pentasill molecular sieves, including aluminosilicate zeolites using ethylene diamine (C2DN) template, from the gel composition 1.85Na(2)O : aAl(2)O(3) : 15.2SiO(2) : 592H(2)O : 19.7C(2)DN in the temperature 177 degrees C for ten days. When a = 0.25 the product was ZSM-5 and then a = 1 the product was ZSM-35 and in between compositions the mixture of two were obtained. Reduce the time of crystallization time to 5 days give nanocrystalline material. XRD and FT-IR spectra in framework region of ZSM-5 synthesized using ethylene diamine template and without template are having similar pattern, however the intensity varies. Scanning electron microscopic picture of the both are varies. The structural stability of the zeolite ZSM-5 synthesized using no template was also found to be lower as compared with that for the ZSM-5 synthesized using ethylene diamine template. These differences. may result from the occluded excess sodium.

}, keywords = {ethylenediamine, Molecular sieve, zeolite}, issn = {0019-4522}, author = {Venkatathri, N.} } @article { ISI:000266061500016, title = {Dependence of Si-29 NMR chemical shielding properties of precursor silicate species, Q(0) on its local structure at the pre-nucleation stages of zeolite synthesis - a DFT based computational correlation}, journal = {Microporous and Mesoporous Materials}, volume = {122}, number = {1-3}, year = {2009}, month = {JUN}, pages = {105-113}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The exploration for new zeolite structures with tailored framework architectures for enhanced catalytic applications requires the knowledge about their nucleation and crystallization at molecular level. Nuclear magnetic resonance (NMR) is one of the most widely tried techniques to understand this. However, by NMR, it is difficult to accurately assign the molecular level precursor silicate structures at the pre-nucleation stages of zeolite synthesis. Hence, understanding the chemical shielding of such precursor molecules using quantum mechanical (QM) computations is extremely useful. Alkali is a fundamental component in the alkali based hydrothermal zeolite synthesis and its nature plays a major role. In the present report, we attempt to understand the differences in the local structure of the primary building block such as Si(OH)(4) (Q(0) silicate species) due to the associated alkali and their influence on NMR chemical shielding properties. Present work reports the calculation of Si-29 NMIR isotropic chemical shifts of T species with different cations such as Na, K and Ca using density functional theory (DFT). Results of natural bonding orbital (NBO) analysis, Perturbation theory energy analysis and electron density iso-surfaces were employed to obtain a deeper insight about their influence on the chemical shielding and on zeolite synthesis. (C) 2009 Elsevier Inc. All rights reserved.

}, keywords = {Ab initio method, Density Functional Theory (DFT), Electron density, NBO analysis, Perturbation theory, Q(0) silicate species, Si-29 NMR chemical shift, synthesis, zeolite}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2009.02.022}, author = {Selvaraj, Kaliaperumal and Kurian, Reshmi} } @article { ISI:000281996100013, title = {Transformation of chemically fine tuned zeolite A precursor into dense lithium aluminosilicates - a comprehensive phase evolution and sintering study}, journal = {Microporous and Mesoporous Materials}, volume = {135}, number = {1-3}, year = {2010}, month = {NOV}, pages = {82-89}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Beyond their conventional revelation as catalysts, zeolites are being perceived as more challenging materials for modern applications. Thermal recrystallization of zeolite precursors is an efficient method for the preparation of dense aluminosilicate ceramics. However, factors viz., nature of the precursor and the way of firing it etc., influence the product quality. The present report is a systematic and detailed account of a phase transformation of Li modified zeolite A precursor using powder X-ray diffraction (PXRD), thermogravimetry (TG), differential thermal analysis (DTA), scanning electron micrographs (SEM), atomic absorption spectroscopy (MS), energy dispersive X-ray (EDX) and density measurement techniques. It involves an amorphisation followed by a recrystallization into lithium aluminosilicate (LAS). A comprehensive correlation of PXRD, TG/DTA, SEM, EDX and density data explains the complexity of high temperature phase transition (25-1200 degrees C). A qualitative phase analysis revealed the mediation of formation of LAS ceramic, beta-spodumene by few satellite transitions of SiO(2). (C) 2010 Elsevier Inc. All rights reserved.

}, keywords = {LAS silicate, Phase evolution, Phase transformation, Powder XRD, zeolite}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2010.06.014}, author = {Selvaraj, Kaliaperumal} } @article { ISI:000288274200014, title = {Adsorption of cresols on zinc-aluminium hydroxides - a comparison with zeolite-X}, journal = {Separation Science and Technology}, volume = {46}, number = {3}, year = {2011}, month = {JAN}, pages = {PII 934305034}, publisher = {TAYLOR \& FRANCIS INC}, address = {530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA}, abstract = {

Liquid phase adsorption of m-cresol on Zn-Al hydroxide adsorbents with three different Zn/Al molar ratios was studied in different solvents and compared with commercial zeolite 13X. Among the three adsorbents, ZA-16 showed adsorption capacity similar to commercial zeolite 13X. Solvents used for the preparation of m-cresol solution were found to influence the adsorption capacity. The adsorption capacity was maximum for the solution of m-cresol in n-hexane. Conventional Langmuir and Freundlich adsorption isotherm equations were used to explain the adsorption behavior. The kinetics of m-cresol adsorption followed the first-order Lagergren kinetic model. p-Cresol/m-cresol separation factor was the highest when toluene was used as the organic medium.

}, keywords = {Adsorption, cresol, zeolite, zinc-aluminium hydroxide}, issn = {0149-6395}, doi = {10.1080/01496395.2010.510494}, author = {Vijayakumar, J. and Chikkala, Suresh K. and Mandal, Sujata and Mayadevi, S.} } @article { ISI:000301936700004, title = {Environmentally benign synthesis of beta-hydroxy sulfides using cyclic carbonates catalyzed by large-pore zeolites}, journal = {Green Chemistry Letters and Reviews}, volume = {5}, number = {1}, year = {2012}, month = {AUG}, pages = {19-26}, publisher = {TAYLOR \& FRANCIS LTD}, address = {4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND}, abstract = {

An efficient one-pot synthesis of beta-hydroxy sulfides from thiophenol and cyclic carbonates catalyzed by large-pore zeolites has been reported. Reaction of thiophenol with ethylene carbonate in the presence of the Na-X zeolite catalyst gave the highest yield of 2-(phenylthio)ethanol (100\%), while reaction with propylene carbonate a highest yield of regioselective product 1-(phenylthio)propan-2-ol was obtained (97\%). Enantiomerically pure 1,2-propylene carbonate gave highly regioselective and stereospecific phenylthiopropanol, demonstrating that original chirality of propylene carbonate is retained. A plausible mechanism has been proposed for zeolite-catalyzed transformation involving a chemoselective nucleophilic attack of thiophenoloxide ion onto the less-substituted carbon of cyclic carbonate. The Na-X zeolite catalyst is recyclable and provides advantages of green chemistry approach to the synthesis of beta-hydroxy sulfides without the use of any solvent.

}, keywords = {beta-hydroxy sulfide, ethylene carbonate, propylene carbonate, thiophenol, zeolite}, issn = {1751-8253}, doi = {10.1080/17518253.2011.574295}, author = {Upare, Pravin P. and Kinage, Anil K. and Shingote, Savita K. and Gupte, Sunil P.} } @article { ISI:000326320000017, title = {Efficient, stable, and reusable silicoaluminophosphate for the one-pot production of furfural from hemicellulose}, journal = {ACS Catalysis}, volume = {3}, number = {10}, year = {2013}, month = {OCT}, pages = {2299-2303}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Development of stable, reusable, and water tolerant solid acid catalysts in the conversion of polysaccharides to give value-added chemicals is vital because catalysts are prone to undergo morphological changes during the reactions With the anticipation that silicoaluminophosphate (SAPO) catalysts will have higher hydrothermal stability, those were synthesized, characterized, and employed in a one-pot conversion of hemicellulose. SAPO-44 catalyst at 170 degrees C within 8 h could give 63\% furfural yield with 88\% mass balance and showed similar activity up to at least 8 catalytic cycles. The morphological studies revealed that SAPO catalysts having hydrophilic characteristics are stable under reaction conditions.

}, keywords = {furfural, Hemicellulose, hydrophilicity, SAPO, water-tolerant catalyst, zeolite}, issn = {2155-5435}, doi = {10.1021/cs400495j}, author = {Bhaumik, Prasenjit and Dhepe, Paresh Laxmikant} } @article { ISI:000319458900005, title = {Modified zeolite immobilized palladium for ligand-free suzuki-miyaura cross-coupling reaction}, journal = {Journal of Organometallic Chemistry}, volume = {738}, year = {2013}, month = {AUG}, pages = {29-34}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A palladium-based catalyst supported on modified ZSM-5 was successfully prepared by a facile procedure. The prepared heterogeneous catalyst Pd@desilicated ZSM-5 showed an excellent catalytic activity at very low Pd loading (0.02 mol\%) for the ligand-free Suzuki-Miyaura coupling reactions of various aryl bromides affording excellent yields of the products. The prepared catalyst presents good recyclability, over four catalytic cycles. (C) 2013 Elsevier B. V. All rights reserved.

}, keywords = {heterogeneous catalysis, Suzuki-Miyaura reaction, zeolite}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2013.03.031}, author = {Kumbhar, Arjun and Kamble, Santosh and Mane, Anand and Jha, Ratnesh Kumar and Salunkhe, Rajashri} }