@article { ISI:000239077500019, title = {Chemo-, regio- and stereo-selective aerial oxidation of limonene to the endo-1,2-epoxide over Mn(Salen)-sulfonated SBA-15}, journal = {Applied Catalysis A-General}, volume = {309}, number = {1}, year = {2006}, month = {JUL}, pages = {144-154}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Mn(Salen) complexes immobilized on sulfonic acid-functionalized SBA-15 molecular sieves (SBA-15-pr-SO3-Mn(Salen)) catalyze the Mukaiyama-type oxidation of R-(+)-limonene selectively to the 1,2-epoxide with molecular oxygen at 298 K (Salen = N,N-ethylenebis(salicylidenaminato)). The endo-diastereomer is formed with a diasteromeric excess of 39.8\%. This catalyst exhibited higher catalytic activity than {\textquoteleft}{\textquoteleft}neat{\textquoteright}{\textquoteright} Mn(Salen) complexes directly supported on SBA-15 or zeolite-Y. A change in the oxidation state of Mn from +3 in the {\textquoteleft}{\textquoteleft}neat{\textquoteright}{\textquoteright} complex to +2 when immobilized on the sulfonated surface is a probable cause for the observed enhancement of catalytic activity. A part of the Mn complexes was leached out of the solid phase during the reaction. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {aerial oxidation of limonene, catalysis by Mn(Salen) complexes, chemo-, immobilized Mn Schiff base complexes, Mesoporous molecular sieves, Mukaiyama-type oxidation, regio- and stereo-selective epoxidation, sulfonic acid-functionalized SBA-15}, issn = {0926-860X}, doi = {10.1016/j.apcata.2006.05.011}, author = {Saikia, Lakshi and Srinivas, D. and Ratnasamy, Paul} } @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} } @article { ISI:000283589900009, title = {Chemoselective hydrogenation of cinnamaldehyde over Pd/CeO2-ZrO2 catalysts}, journal = {Catalysis Letters}, volume = {140}, number = {1-2}, year = {2010}, month = {NOV}, pages = {55-64}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Selective hydrogenation of cinnamaldehyde over Pd (2 wt\%) supported on CeO2, ZrO2 and CeO2-ZrO2 catalysts is reported for the first time. In general, the olefinic (C=C) group of cinnamaldehyde is preferentially hydrogenated compared to the carbonyl (C=O) group. This selectivity preference could, however, be altered or reversed by adding alkali additives to the catalyst. The influence of additive on the structure and redox properties of the active sites and correlation of that with selective hydrogenation activity is investigated.

}, keywords = {alpha, beta-Unsaturated aldehyde, Ceria-zirconia, Cinnamaldehyde, Hydrogenation, palladium catalyst}, issn = {1011-372X}, doi = {10.1007/s10562-010-0423-z}, author = {Bhogeswararao, Seemala and Srinivas, D.} } @article { ISI:000303698100011, title = {Calcined, rare earth modified hydrotalcite as a solid, reusable catalyst for dimethyl carbonate synthesis}, journal = {Industrial \& Engineering Chemistry Research}, volume = {51}, number = {18}, year = {2012}, month = {MAY}, pages = {6356-6363}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

An eco-friendly building block and fuel additive dimethyl-carbonate (DMC)-was synthesized through a benign route by transesterification of propylene carbonate (PC) with methanol. The catalytic activity of a series of calcined, rare earth elements (La3+, Ce3+, Pr3+, Sm3+, and Y3+; 2-10 mol \%) incorporated Mg-Al hydrotalcites (HT) was evaluated for this reaction. Among several, the La (8 mol \%) modified HT showed the highest activity (PC conversion = 65.4 mol \% and DMC selectivity = 88 mol \% at 150 degrees C and in 2 h). Basicity of the catalyst played an important role on the transesterification activity. The influence of reaction parameters and calcination temperature on the catalytic activity of HT was investigated. The La modified HT catalyst was heterogeneous and could be reused with little loss of activity.

}, issn = {0888-5885}, doi = {10.1021/ie300678p}, author = {Unnikrishnan, P. and Srinivas, D.} } @article { ISI:000356739400008, title = {Catalytic conversion of furfural to industrial chemicals over supported Pt and Pd catalysts}, journal = {Journal of Catalysis}, volume = {327}, year = {2015}, month = {JUL}, pages = {65-77}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Several industrial chemicals were prepared by hydrogenation of furfural over gamma-Al2O3-supported Pt and Pd catalysts. These catalysts were active even at room temperature (25 degrees C). While the Pt catalysts were selective for C=O hydrogenation (yielding furfuryl alcohol), Pd facilitated ring hydrogenation (producing tetrahydrofurfuryl alcohol). At high temperature (240 degrees C), the Pd catalyst exhibited excellent decarbonylation activity forming furan with 85\% yield. The catalyst was reusable even in the absence of external hydrogen. The presence of hydrogen led to ring-opened products. Furan was quantitatively converted at 25 degrees C to tetrahydrofuran. Acidity of the support made a marked influence on the activity and selectivity. Pt on SO4-ZrO2 favored hydrogenolysis yielding 2-methyl furan along with furan with \>75 wt\% selectivity. Particle size, metal dispersion, and solvent influenced catalytic activity. Differences in structure and mode of furfural adsorption were also the causes for variations in selectivity of these supported Pt and Pd catalysts. (C) 2015 Elsevier Inc. All rights reserved.

}, keywords = {Biomass to fuels and chemicals, Decarbonylation, furfural, Hydrogenation, Hydrogenolysis, Supported Pt and Pd catalysts}, issn = {0021-9517}, doi = {10.1016/j.jcat.2015.04.018}, author = {Bhogeswararao, Seemala and Srinivas, D.} }