@article { ISI:000271982400003, title = {Characterization of clay intercalated cobalt-salen catalysts for the oxidation of p-cresol}, journal = {Applied Catalysis A-General}, volume = {370}, number = {1-2}, year = {2009}, month = {NOV}, pages = {16-23}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The intercalation of cobalt-salen complexes into the interlamelar spaces of montmorillonite clay was investigated by various characterization studies. The {\textquoteleft}{\textquoteleft}neat{\textquoteright}{\textquoteright} cobalt-salen complex showed a weight loss at 368 degrees C while the weight loss for the corresponding intercalated complex was observed at much higher temperature of 492 degrees C due to decomposition of the complex. The thermal stabilization observed was due to the host-guest interaction of clay and metal complex and thus confirmed the intercalation. The XANES spectrum of Co(salen)-mont sample revealed the change of symmetry from the tetrahedral in plane to the octahedral structure having an axial bonding of oxygen to the cobalt, indicating that cobalt atoms in Co(salen)-mont were coordinated axially with the lattice oxygen of montmorillonite. Both XANES and EXAFS results indicated that cobalt atoms in Co(salen)-mont form two additional Co-O bonds with a bond length of 0.199 nm by the intercalation while retaining the Co-salen structure. Co-salen intercalated into the montmorillonite clay showed the highest activity for the air oxidation of p-cresol, giving 88\% selectivity to the oxidation products. Effects of NaOH concentration and various solvents on the conversion and selectivity patterns also have been studied. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Cobalt-oxygen bond, Cobalt-salen, Extended X-ray absorption fine structure, Intercalation, Lattice oxygen, Montmorillonite, X-ray absorption near edge structure}, issn = {0926-860X}, doi = {10.1016/j.apcata.2009.09.003}, author = {Kshirsagar, V. S. and Garade, Ajit C. and Mane, R. B. and Patil, K. R. and Yamaguchi, A. and Shirai, M. and Rode, C. V.} } @article {Kulkarni, title = {Continuous hydroxyalkylation of p-Cresol to 2,2 {\textquoteleft}-methylenebis(4-Methylphenol) in a fixed bed reactor}, journal = {Journal of Chemical Engineering of Japan}, volume = {42}, number = {10}, year = {2009}, month = {OCT}, pages = {782-787}, abstract = {

{Catalytic activity of various solid acid catalysts is evaluated for the continuous hydroxyalkylation of p-cresol to [

}, author = {Garade, Ajit C. and Hengne, Amol M. and Deshpande, Tushar N. and Shaligram, Sayali V. and Shirai, Masayuki and Rode, Chandrashekhar V.} } @article { ISI:000263864900016, title = {Efficient gamma-Fe2O3 catalyst for liquid phase air oxidation of p-hydroxybenzyl alcohol under mild conditions}, journal = {Catalysis Communications}, volume = {10}, number = {5}, year = {2009}, month = {JAN}, pages = {485-489}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

gamma-Fe2O3 (maghemite) particles were synthesized at 5 degrees C (LT, low temperature) and 95 degrees C (HT, high temperature) using a simple chemical protocol. The major reflection in XRD was observed to be of the gamma-Fe2O3 phase which was further supported by the XPS analysis. Fe3+ species were responsible for initiation of the oxidation of p-hydroxybenzyl alcohol. SEM revealed that the morphologies of the catalysts were different for samples prepared at two different temperatures. gamma-Fe2O3 (LT) showed the highest catalyst activity (84\% conversion) for liquid phase air oxidation of p-hydroxybenzyl alcohol with 94\% selectivity to the oxidation products at 370 K and ambient pressure conditions. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Air oxidation, gamma-Fe2O3, p-Hydroxybenzaldehyde, p-Hydroxybenzyl alcohol, scanning electron microscopy}, issn = {1566-7367}, doi = {10.1016/j.catcom.2008.10.044}, author = {Garade, Ajit C. and Bharadwaj, M. and Bhagwat, S. V. and Athawale, A. A. and Rode, C. V.} } @article { ISI:000271103500011, title = {Heterogeneous cobalt-saponite catalyst for liquid phase air oxidation of p-cresol}, journal = {Industrial \& Engineering Chemistry Research}, volume = {48}, number = {21}, year = {2009}, month = {NOV}, pages = {9423-9427}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Heterogeneous Co-saponite was found to be an efficient catalyst for the liquid phase oxidation of p-cresol under mild conditions. Divalent cobalt tons were found to be in both the tetrahedral and octahedral positions of the saponite clay. Studies on the effect of reaction parameters showed that the rate of reaction increased with increase in Co loading from 5 to 13\% and then remained constant up to 30\% of Co loading, while the rate of oxidation showed a first-order dependence on the partial pressure of oxygen up to 300 kPa. Results of oxidation experiments over Co-saponite, in an Inert atmosphere, and the XPS studies Suggest Mars-van Krevelen pathway operating, which involves lattice oxygen of Co-saponite in the liquid phase oxidation of p-cresol.

}, issn = {0888-5885}, doi = {10.1021/ie801941e}, author = {Kshirsagar, Vikas S. and Garade, Ajit C. and Patil, Kashinath R. and Jha, Ratnesh Kumar and Rode, Chandrashekhar V.} } @article { ISI:000266263000034, title = {Liquid phase oxidation of p-cresol over cobalt saponite}, journal = {Topics in Catalysis}, volume = {52}, number = {6-7}, year = {2009}, month = {JUN}, pages = {784-788}, publisher = {SPRINGER/PLENUM PUBLISHERS}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Liquid phase oxidation of p-cresol was carried out over a Co-saponite catalyst in a temperature and pressure range of 333-393 K and 20-827 kPa, respectively in n-propanol. Co-saponites with varying cobalt content (5-30\%) were prepared and screened among which 13\% Co-saponite gave the highest conversion of 92\% of p-cresol with 92\% selectivity to p-hydroxybenzaldehyde without formation of any non-oxidation products.

}, keywords = {Co-saponite, Liquid phase oxidation, p-Cresol, p-Hydroxybenzaldehyde, XPS}, issn = {1022-5528}, doi = {10.1007/s11244-009-9199-z}, author = {Kshirsagar, Vikas S. and Garade, Ajit C. and Patil, Kashinath R. and Shirai, Masayuki and Rode, Chandrashekhar V.} } @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.} } @article { ISI:000263491600023, title = {Selective hydroxyalkylation of phenol to bisphenol F over dodecatungstophosphoric acid (DTP) impregnated on fumed silica}, journal = {Applied Catalysis A-General}, volume = {354}, number = {1-2}, year = {2009}, month = {FEB}, pages = {176-182}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The catalyst activity of various solid acids, such as fumed Silica (SiO(2)) dodecatungstophosphoric acid (DTP), DTP impregnated on SiO(2), amberlyst-15 and montmorillonite KSF/0, was studied for the hydroxyalkylation of phenol to bisphenol F. A well-dispersed DTP on SiO2 catalyst was prepared by the wet impregnation method. The effect of DTP loading on SiO(2) was also compared with bulk DTP and other solid acid catalysts. 20\% DTP/SiO(2) catalyst gave the highest products yield of 34.2\% and selectivity of 90.1\% to bisphenol F, at 353 K and with a phenol-to-formaldehyde mole ratio of 5:1. Ammonia TPD studies of various catalysts showed that an appropriate combination of both strong and weak acid sites of DTP/SiO(2) Was mainly responsible, rather than only the stronger acidity of bulk DTP, for its highest catalytic activity and selectivity. The effect of various reaction parameters like mole ratio, catalyst concentration, temperature and reaction time on product yield and bisphenol F selectivity was also investigated. The catalyst recycle was established by catalyst activity testing. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Bisphenol F, Hydroxyalkylation, NH(3)-TPD, Reaction pathways, solid acid catalysts}, issn = {0926-860X}, doi = {10.1016/j.apcata.2008.11.025}, author = {Garade, Ajit C. and Kshirsagar, V. S. and Rode, C. V.} } @article { ISI:000270338700005, title = {Solid acid catalysts: modification of acid sites and effect on activity and selectivity tuning in various reactions}, journal = {Catalysis Surveys from Asia}, volume = {13}, number = {3}, year = {2009}, month = {SEP}, pages = {205-220}, publisher = {SPRINGER/PLENUM PUBLISHERS}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

The effects of acidity and variation in concentration of acid sites of dodecatungstophosphoric acid (DTP), supported DTP and montmorillonite-K catalysts were studied for various organic reactions such as the hydroxyalkylation of phenols to bisphenols, intramolecular rearrangement of benzyl phenyl ether (BPE) to 2-benzyl phenol (2-BP) and selective cleavage of tert-butyldimethylsilyl (TBDMS) ether into the corresponding alcohol. Both dodecatungstophosphoric acid (DTP) impregnated on silica (SiO(2)) and montmorillonite catalysts showed the highest catalyst activity with 90-95\% selectivity to bisphenol for the hydroxyalkylation of phenols to give bisphenol. Temperature Programmed Desorption (TPD) of ammonia and activity results of various catalysts showed that an appropriate combination of both strong and weak acidic sites in the catalyst was highly desirable for high bisphenol selectivity. A 10\% DTP/SiO(2) catalyst was found to be highly selective for the cleavage of TBDMS ether into the corresponding alcohol at room temperature giving a high TON of 9.5 x 10(5) even after the 4th recycle. DTP was also found to be a promising solid acid catalyst for the intramolecular rearrangement of BPE giving 2-BP.

}, keywords = {Acidity tuning, Catalytic cleavage, Hydroxyalkylation, Intramolecular rearrangement, solid acid catalysts}, issn = {1571-1013}, doi = {10.1007/s10563-009-9078-4}, author = {Rode, C. V. and Garade, Ajit C. and Chikate, Rajeev C.} } @article { ISI:000276010700025, title = {Acidity tuning of montmorillonite K10 by impregnation with dodecatungstophosphoric acid and hydroxyalkylation of phenol}, journal = {Applied Clay Science}, volume = {48}, number = {1-2, SI}, year = {2010}, month = {MAR}, pages = {164-170}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Acidity tuning of montmorillonite K10 (mont K10) was achieved by impregnating with dodecatungstophosphoric acid (DTP). The effect on the hydroxyalkylation of phenol was studied at 353 K with phenol to formaldehyde molar ratio of 5. The nature and strength of acid sites were determined by NH(3)-TPD measurement while the distribution of Brensted and Lewis acid sites expressed as B/L ratio, was determined by pyridine IR technique. Among various loadings of DTP (5-60\%) studied for the hydroxyalkylation of phenol, 20\% DTP/mont K10 showed the highest catalyst activity (90\% selectivity to bisphenol F with 28\% conversion of phenol). Both total concentration of acid sites and the distribution of acid sites in a high temperature region were required for the high bisphenol F selectivity. Our catalyst (20\% DTP/Mont K10) could be recycled three times. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Acidity tuning, Dodecatungstophosphoric acid/Montmorillonite K10, Hydroxyalkylation, Impregnation, Temperature programmed desorption}, issn = {0169-1317}, doi = {10.1016/j.clay.2009.11.042}, author = {Garade, Ajit C. and Kshirsagar, V. S. and Mane, R. B. and Ghalwadkar, Ajay A. and Joshi, U. D. and Rode, C. V.} } @article { ISI:000275524800024, title = {Hydroxyalkylation of p-Cresol to 2,2 {\textquoteleft}-methylenebis(4-methylphenol) using Sn/Si-MCM-41 catalysts}, journal = {Chemistry Letters}, volume = {39}, number = {2}, year = {2010}, month = {FEB}, pages = {126-127}, publisher = {CHEMICAL SOC JAPAN}, address = {1-5 KANDA-SURUGADAI CHIYODA-KU, TOKYO, 101-8307, JAPAN}, abstract = {

Sn/Si-MCM-41 has exhibited an excellent catalytic activity [70\% product yield with 88\% selectivity to 2,2{\textquoteright}-methylenebis(4-methylphenol)] for the selective hydroxyalkylation of p-cresol. At equal level of Sn loading, Sn/Si-MCM-41 prepared by direct hydrothermal synthesis showed higher activity than Sn-impregnated Si-MCM-41 catalyst.

}, issn = {0366-7022}, doi = {10.1246/cl.2010.126}, author = {Garade, Ajit C. and Niphadkar, Prashant S. and Joshi, Praphulla N. and Rode, Chandrashekhar V.} } @article { ISI:000283204900015, title = {Micro-/meso-porous stannosilicate composites (Sn-MFI/MCM-41) via two-step crystallization process: process parameter-phase relationship}, journal = {Microporous and Mesoporous Materials}, volume = {136}, number = {1-3}, year = {2010}, month = {DEC}, pages = {115-125}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Sn-MFI/MCM-41 composite material was successfully synthesized by monitoring the re-crystallization time in a simple two-step crystallization process. The length of period allowed for the recrystallization of the precursor species was found to be a controlling factor to achieve either the end members viz. Sn-MCM-41 and Sn-MFI or Sn-MFI/MCM-41 composite material. Powder XRD, FTIR, SEM, TEM, nitrogen sorption measurement, DRUV-vis and hydroxyalkylation of p-cresol reaction were used as the characterization tools. Attempts were also made to establish the relationship between type of phase formed and the process parameters such as aging time, re-crystallization temperature, time and molar ratios of TPAOH/SiO(2), CTMABr/SiO(2) and SiO(2)/SnO(2) in the gel. (C) 2010 Elsevier Inc. All rights reserved.

}, keywords = {composites, Crystallization, Micro-/meso-porous stannosilicate, p-Cresol hydroxyalkylation, Sn-MCM-41, Sn-MFI}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2010.08.005}, author = {Niphadkar, Prashant S. and Garade, Ajit C. and Jha, Ratnesh Kumar and Rode, Chandrashekhar V. and Joshi, Praphulla N.} } @article { ISI:000280359700010, title = {Pd-functionalized carbon nanotubes for selective hydrogenation of 2-butyne-1,4-diol}, journal = {Advanced Science Letters}, volume = {3}, number = {3}, year = {2010}, month = {SEP}, pages = {313-318}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

Multiwalled carbon nanotubes were prepared by thermal decomposition method followed by acid treatment and Pd-functionalization with PdCl2 by wet impregnation method. The Pd functionlized carbon nanotubes catalyst was characterized by BET, FT-IR, Raman, XRD, EDX, ICP-OES, SEM and TEM and was evaluated for its activity for hydrogenation of 2-butyne-1,4-diol. It showed higher selectivity (93\%) to 2-butene-1,4-diol than Pd supported on commercial carbon (70\% selectivity to 2-butene-1,4-diol) for complete conversion of 2-butyne-1,4-diol. The catalyst also exhibited excellent stability as evidenced by the three catalyst recycle experiments.

}, issn = {1936-6612}, doi = {10.1166/asl.2010.1128}, author = {Nadgeri, Jayprakash M. and Garade, Ajit C. and Tambe, Romana A. and Gokhale, Suresh P. and Rode, Chandrashekhar V.} } @article { ISI:000279333000002, title = {Structure-activity studies of dodecatungstophosphoric acid impregnated bentonite clay catalyst in hydroxyalkylation of p-cresol}, journal = {Catalysis Communications}, volume = {11}, number = {11}, year = {2010}, month = {JUN}, pages = {942-945}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Bentonite clay impregnated with dodecatungstophosphoric acid (20\% DTP/BNT) showed an excellent activity, selectivity and stability [95\% product yield with 94\% selectivity to 2, 2{\textquoteright}-methylenebis (4-methylphenol), DAM] for the hydroxyalkylation of p-cresol with formaldehyde at 353 K and for a mole ratio of 5. Ammonia-TPD results showed that an increase in total concentration of acid sites from 4.9 of parent bentonite to 11.6 micromoles per surface area NH(3) (mu molS(-1) NH(3)) of 20\% DTP/BNT was due to a strong interaction of protons of bulk DTP with surface hydroxyl groups of BNT as evidenced by (31)P NMR studies. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {(31)P CPMAS NMR, Bentonite, Hydroxyalkylation, p-Cresol, surface modification}, issn = {1566-7367}, doi = {10.1016/j.catcom.2010.04.008}, author = {Garade, Ajit C. and Kshirsagar, V. S. and Jha, Ajay and Rode, C. V.} } @article { ISI:000289764000056, title = {Control of competing hydrogenation of phenylhydroxylamine to aniline in a single-step hydrogenation of nitrobenzene to p-aminophenol }, journal = {Industrial \& Engineering Chemistry Research}, volume = {50}, number = {9}, year = {2011}, month = {MAY}, pages = {5478-5484}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Two steps involving catalytic hydrogenation of nitrobenzene to phenylhydroxylamine (PHA) in acid medium and its rearrangement to p-aminophenol (PAP) were studied separately in a batch reactor, using a well-characterized 3\% Pt/C catalyst. The first step of hydrogenation of nitrobenzene to PHA could be carried out at 303 K and a H(2) pressure of 0.69 MPa with complete conversion of nitrobenzene, while the achieved selectivity to PHA was higher than 90\% with some formation of aniline, even at lower temperature. The second step of PHA rearrangement to PAP could be achieved under a hydrogen atmosphere at elevated temperature of 353 K to give a maximum selectivity to PAP of 74\%.

}, issn = {0888-5885}, doi = {10.1021/ie102544a}, author = {Nadgeri, Jayprakash M. and Biradar, Narayan S. and Patil, Priyanka B. and Jadkar, Sachin T. and Garade, Ajit C. and Rode, Chandrashekhar V.} } @article { ISI:000294374900007, title = {Liquid phase oxidation of p-vanillyl alcohol over synthetic Co-saponite catalyst}, journal = {Applied Clay Science}, volume = {53}, number = {2, SI}, year = {2011}, month = {AUG}, pages = {157-163}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Effect of cobalt loading on porosity of synthetic Co-saponite catalysts and on the air oxidation of p-vanillyl alcohol was studied by varying Co content in the range of 5\% to 30\% using in situ precipitation method. The pore size increased from 1.29 to 3.69 nm indicating a transition from micro to meso porosity, with increase in Co loading from 5\% to 30\%. The distribution ratio of Co(3)O(4)/CoO phases as estimated from TPR studies, also increased from 0.84 to 1.67 with increase in Co loading from 5\% to 13\% and remained almost constant (1.7) with further increase in Co loading up to 30\%. The highest activity (conversion 55\%) and selectivity of 99\% to p-vanillin obtained for 13\% Co-saponite in p-vanillyl alcohol oxidation was due to the highest distribution ratios of Co(3)O(4)/CoO phases. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {Co-saponite, Cobalt oxide phase ratio, p-Vanillin, p-Vanillyl alcohol oxidation, Porosity transition, Temperature programmed reduction}, issn = {0169-1317}, doi = {10.1016/j.clay.2010.10.026}, author = {Garade, Ajit C. and Biradar, Narayan S. and Joshi, S. M. and Kshirsagar, V. S. and Jha, Ratnesh Kumar and Rode, Chandrashekhar V.} } @article { ISI:000291908500016, title = {Reply to the comments of vicente et al. on {\textquoteleft}{\textquoteleft}liquid phase oxidation of p-vanillyl alcohol over synthetic co-saponite catalyst{\textquoteright}{\textquoteright} applied clay science (2010), doi:10.1016/j.clay.2010.10.026}, journal = {Applied Clay Science}, volume = {52}, number = {4}, year = {2011}, month = {JUN}, pages = {432}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, issn = {0169-1317}, doi = {10.1016/j.clay.2011.04.008}, author = {Rode, Chandrashekhar V. and Garade, Ajit C. and Biradar, Narayan S. and Kshirsagar, V. S.} } @article { ISI:000301406900010, title = {MCM-41 supported phosphotungstic acid for the hydroxyalkylation of phenol to phenolphthalein}, journal = {Industrial \& Engineering Chemistry Research}, volume = {51}, number = {10}, year = {2012}, month = {MAR}, pages = {3916-3922}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A novel application of phosphotungstic acid, H3PW12O40 (PWA) supported on MCM-41 molecular sieve as a solid acid catalyst has been demonstrated for the synthesis of phenolphthalein by hydroxyalkylation of phenol and phthalic anhydride. PWA/MCM-41 (20\%) showed the highest activity as compared to that of parent PWA and MCM-41 individually, due to the excellent dispersion of PWA on MCM-41 leading to the redistribution of Bronsted and Lewis acid sites on MCM-41. The effect of PWA loading on phthalic anhydride conversion and phenolphthalein selectivity was also studied. All these prepared catalysts were characterized by XRD, N-2 adsorption-desorption isotherm, pyridine-FTIR, and NH3-TPD. The effect of various reaction parameters, namely, mole ratios, catalyst concentration, temperature, reaction time, and percentage of PWA present in the catalysts on conversion and selectivity of products has been also investigated. The utility of 20\% PWA/MCM-41 catalyst was established by its efficient activity for hydroxyalkylation of phenol and p-cresol with formaldehyde to the corresponding dihydroxydiarylmethane products.

}, issn = {0888-5885}, doi = {10.1021/ie201989g}, author = {Jha, Ajay and Garade, Ajit C. and Mirajkar, Subhash P. and Rode, Chandrashekhar V.} } @article { ISI:000322432600012, title = {Magnetically separable single-site Ti-Fe3O4@MCM-41 catalyst for selective epoxidation of olefins}, journal = {Industrial \& Engineering Chemistry Research}, volume = {52}, number = {29}, year = {2013}, month = {JUL}, pages = {9803-9811}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Magnetically separable Ti-Fe3O4@MCM-41 (Ti-MS) catalysts were prepared by postgrafting Ti with varying loading on mesoporous silica containing dispersed magnetite. The hexagonal structure of Ti-MS catalysts with a periodicity in the pores and a highly ordered hexagonal matrix was established by X-ray diffraction and transmission electron microscopy, while diffuse reflectance UV showed the isolated tetrahedral Ti species coordinated with O2-. From the Fourier transform infrared studies, the extent of Ti-O-Si linkage was found to increase with increase in Ti-loading from 1 to 5 wt \%beyond which (10\%), the intensity of Ti-O-Si band decreased due to the polymerization of the Ti on the silica surface. Silanol groups on the surface of silica interact with the precursor Ti((OPr)-Pr-i)(4) to give site isolated tetrahedral Ti-species responsible for complete selectivity to the epoxide in the epoxidation of cyclooctene. The magnetic property facilitated easy recovery of the catalyst for its successful eight recycles showing its stability under reaction conditions.

}, issn = {0888-5885}, doi = {10.1021/ie4013248}, author = {Jha, Ajay and Patil, Chetana R. and Garade, Ajit C. and Rode, Chandrashekhar V.} } @article { ISI:000317945100020, title = {Metal cation-exchanged montmorillonite clay as catalysts for hydroxyalkylation reaction}, journal = {Applied Clay Science}, volume = {74}, number = {SI}, year = {2013}, month = {APR}, pages = {141-146}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Several solid acid catalysts were prepared by exchanging metal cations such as Zn2+, Fe3+ and Al3+ with montmorillonite clay. Among these, Al-montmorillonite showed the highest acidity determined by the pyridine-IR as well as NH3-TPD methods. A systematic comparison of the performance of these catalysts along with parent montmorillonite was carried out for the hydroxyalkylation of p-cresol with formaldehyde to give 2, 2{\textquoteright}-methylenebis (4-methyl phenol) (DAM). It was found that the activity of these catalysts was in accordance with the increase in acidity of parent montmorillonite after the exchange of cations in the order of Zn2+, Fe3+ and Al3+. The selectivity pattern was also influenced by the exchanged cations. Since Al-montmorillonite showed the highest conversion of 51\% with 98\% selectivity to DAM, the effects of various reaction parameters, namely, mole ratio, catalyst concentration, temperature, reaction time on conversion and selectivity pattern were also studied using the same catalyst This catalyst also showed an excellent stability as evidenced by its eight times reuse. (C) 2012 Published by Elsevier B.V.

}, keywords = {Cations-exchanged clay, Montmorillonite, NH3-TPD, Pyridine-IR}, issn = {0169-1317}, doi = {10.1016/j.clay.2012.10.005}, author = {Jha, Ajay and Garade, Ajit C. and Shirai, M. and Rode, C. V.} } @article { ISI:000328665300008, title = {Effect of SnO2/Al2O3 ratio of Si-based MFI on its acidity and hydrophobicity: application in selective hydroxyalkylation of p-cresol}, journal = {Catalysis Communications}, volume = {44}, number = {SI}, year = {2014}, month = {JAN}, pages = {29-34}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Silica based MR type molecular sieves with various SnO2/Al2O3 ratios were synthesized from gels having molar compositions SiO2:xSnO(2):yAl(2)O(3):0.23(TPA)(2)O:35H(2)O where 0 \<= x \<= 0.02 and 0 \<= y \<= 0.01. Recyclable, Al-free Sn-MFI catalyst showed 31\% conversion of formaldehyde with 100\% selectivity to 2,2{\textquoteright}-methylenebis(4-methylphenol) in hydroxyalkylation of p-cresol with formaldehyde on account of moderate acidity and higher hydrophobicity. (C) 2013 Elsevier B.A. All rights reserved.

}, keywords = {Al-27 MAS NMR, Hydroxyalkylation, Molecular sieves, p-Cresol, Stannosilicate}, issn = {1566-7367}, doi = {10.1016/j.catcom.2013.08.002}, author = {Garade, Ajit C. and Malwadkar, A. V. and Niphadkar, P. S. and Jha, Ratnesh Kumar and Joshi, P. N. and Rode, C. V.} }