@article { ISI:000226290900011, title = {Rearrangement of allyl phenyl ether over Al-MCM-41}, journal = {Journal of Catalysis}, volume = {229}, number = {1}, year = {2005}, month = {JAN}, pages = {105-113}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Claisen rearrangement of allyl phenyl ether to o-allylphenol and a dihydrobenzofuran derivative was investigated over MCM-41 with different Si/Al ratios. Higher aluminum content, higher reaction temperatures, and longer run duration favor the formation of the ring compound 2,3-dihydro-2-methyl benzofuran. There is a close relationship between acidity and conversion, which suggests that the reaction occurs inside the large pores of MCM-41. The influence of temperature and catalyst Si/Al ratio on the reaction are examined by kinetic analysis, under the assumption of a first-order consecutive reaction. (C) 2004 Elsevier Inc. All rights reserved.

}, keywords = {Al-MCM-41, allyl phenyl ether, Claisen rearrangement, Mesoporous material, molecular rearrangement, Solid acids}, issn = {0021-9517}, doi = {10.1016/j.jcat.2004.09.027}, author = {Mathew, Nevin T. and Khaire, S. and Mayadevi, S. and Jha, Ratnesh Kumar and Sivasanker, S.} } @article { ISI:000251828300003, title = {Activation and reactivity of epoxides on solid acid catalysts}, journal = {Journal of Catalysis}, volume = {252}, number = {2}, year = {2007}, month = {DEC}, pages = {148-160}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

The aminolysis of epoxides over novel solid catalysts (Bronsted-acidic SBA-15 functionalized with propylsulfonic acid and Lewis-acidic Ti-MCM-41) is reported. The acidic properties of these catalysts were determined by FTIR spectroscopy and temperature-programmed desorption of pyridine and NH3, respectively. The mesoporous solid acids of the present study are reusable and exhibit significantly higher catalytic activities than known catalysts for opening of the oxirane ring with nitrogen (aromatic and aliphatic amines)-containing and oxygen (alcohols)-containing nucleophiles. A range of beta-amino, alcohols with high regioselectivity and stereoselectivity were synthesized. Adsorption studies as well as the sigmoid shape of the conversion- versus-time plots show that the epoxide and amine compete for adsorption on the acidic sites (-SO3H or Ti4+) on the catalyst surface. Epoxide adsorption and activation on acid sites are the more critical processes. Catalytic activity decreases with increasing basicity of the amines and/or the alcohol, as well as the dielectric constant of the solvent. (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {aminolysis and alcoholysis of epoxides, beta-Amino alcohols, ring opening of epoxides, SBA-15 functionalized with propylsulfortic acid, Solid acids, Ti-MCM-41}, issn = {0021-9517}, doi = {10.1016/j.jcat.2007.10.002}, author = {Saikia, Lakshi and Satyarthi, J. K. and Srinivas, Darbha and Ratnasamy, P.} } @article { ISI:000256178900021, title = {Heteropolyacid supported on acidic clay: a novel efficient catalyst for alkylation of ethylbenzene with dilute ethanol to diethylbenzene in presence of C-8 aromatics}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {285}, number = {1-2}, year = {2008}, month = {APR}, pages = {155-161}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Vapor phase alkylation of ethylbenzene with ethanol to diethylbenzene is industrially relevant. Diethylbenzene is an important raw material for the conversion of divinyl benzene monomer. Conventionally, it is prepared from diacetophenone by reduction. It is also prepared by vapor phase alkylation of ethylbenzene with ethylene using zeolitic catalysts. The efficacy of dodecatungsotphosphoric acid (DTPA) supported on acid treated clay has been evaluated in the current work in the alkylation of ethylbenzene with 80\% (w/w) ethanol. 15\% (w/w) DTPA/K-10 clay was found to be an efficient and robust catalyst. The use of aqueous ethanol and a mixed C-8 stream lowers the cost of production. A kinetic model is developed by studying the important process parameters with 15\% (w/w) DTPA/K-10 as the catalyst. (c) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Alkylation, diethylbenzene, Heteropolyacid, kinetics, Solid acids}, issn = {1381-1169}, doi = {10.1016/j.molcata.2007.11.018}, author = {Bokade, Vijay V. and Yadav, Ganapati D.} } @article { ISI:000262658000018, title = {Montmorillonite for selective hydroxyalkylation of p-cresol}, journal = {Applied Clay Science}, volume = {43}, number = {1}, year = {2009}, month = {JAN}, pages = {113-117}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Performances of montmorillonite titanium silicate (TS-1) and dodecatungstophosphoric acid (DTP) were compared for the hydroxyalkylation of p-cresol into dihydroxydiarylmethane (DAM). Ammonia TPD studies of various catalysts showed that an appropriate combination of both strong and weak acid sites of montmorillonite was mainly responsible rather than only the stronger acidity of bulk DTP for its highest catalytic activity for selective hydroxyalkylation of p-cresol to DAM. The selectivity to DAM could be enhanced by adjusting reaction conditions like mole ratio of p-cresol to formaldehyde, reaction temperature, catalyst concentration, solvent and reaction time. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Ammonia TPD, Dihydroxydiarylmethane, Hydroxyalkylation, Montmorillonite, Solid acids}, issn = {0169-1317}, doi = {10.1016/j.clay.2008.07.015}, author = {Garade, Ajit C. and Mate, Vivek R. and Rode, C. V.} }