@article { ISI:000231401000008, title = {Influence of silica source in the catalytic activity and heterogenity of mesoporous vanadosilicates}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {239}, number = {1-2}, year = {2005}, month = {SEP}, pages = {57-63}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Vanadium-substituted ordered mesoporous silicates (V-OMS) were synthesized hydrothermally using two common silica sources, viz. fumed silica and tetraethyl orthosilicate, and their surface properties and catalytic activities were evaluated in the liquid phase oxidation of 1-napthol using aqueous H2O2 as an oxidant. The catalysts were characterized by XRD, N-2, adsorption-desorption, DRUV-vis and TPR to evaluate the mesostructural ordering and the local environment of vanadium in the MCM-41 matrix. Characterization data of the fresh calcined catalysts reveal a more ordered hexagonal structure for the V-MCM-41 catalyst prepared by using tetraethyl orthosilicate as the silica source while spent catalyst showed that the material is less stable than the V-MCM-41 catalyst prepared by using fumed silica as the silica source. Further, the observed differences in the selectivity behavior of extracted and calcined forms of both vanadium catalysts shows that the treatment conditions had a decisive role in the formation of extra framework metal species and further in the mesoscopic structural ordering. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {1-napthol, MCM-41, Mesoporous, Oxidation, Vanadium}, issn = {1381-1169}, doi = {10.1016/j.molcata.2005.05.029}, author = {Shylesh, S. and Mirajkar, Subhash P. and Singh, A. P.} } @article { ISI:000231197500017, title = {Vanadium-containing ordered mesoporous silicas: synthesis, characterization and catalytic activity in the hydroxylation of biphenyl}, journal = {Applied Catalysis A - General}, volume = {290}, number = {1-2}, year = {2005}, month = {AUG}, pages = {148-158}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A series of vanadium-containing ordered mesoporous MCM-41 materials (V-OMS) have been synthesized by direct hydrothermal (VMCM-41) and grafting (V/MCM-41) methods using hexadecyl trimethyl ammonium bromide (HDTMABr) as the structure-directing agent. The physico-chemical properties of the vanadium-containing materials were characterized in detail by ICP-OES, XRD, Fr-IR, N-2 adsorption-desorption, DRUV-VIS, TPR, XPS and SEM techniques. The redox performances of the vanadium-modified mesoporous materials were tested in the hydroxylation of biphenyl using aqueous H2O2 (30 wt.\%) as oxidant. For a better exploitation of the catalytic activity, the reaction parameters are optimized in terms of temperature, solvent, oxidant, etc. A comparison between the catalytic activity values of the vanadium-containing mesoporous materials prepared by the two routes shows that vanadium-substituted (V-MCM-41) materials had increased activity and improved selectivity for mono hydroxyl products in the hydroxylation reaction of biphenyl compared to the V/MCM-41 catalysts. The heterogenity of the catalysts was verified by a series of leaching studies. Both the catalysts enhance the leaching of active vanadia species during the reaction; among them, V/MCM-41 shows the least heterogenity. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {biphenyl, heterogenity, MCM-41, Mesoporous molecular sieves, Vanadium}, issn = {0926-860X}, doi = {10.1016/j.apcata.2005.05.012}, author = {George, J. and Shylesh, S and Singh, AP} } @article { ISI:000230768400012, title = {Vanadium-containing ordered mesoporous silicates: does the silica source really affect the catalytic activity, structural stability, and nature of vanadium sites in V-MCM-41?}, journal = {Journal of Catalysis}, volume = {233}, number = {2}, year = {2005}, month = {JUL}, pages = {359-371}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

A series of vanadium-substituted mesoporous materials were synthesized hydrothermally with the use of two commonly used silica Sources. fumed silica and tetra ethyl orthosilicate. The extent of mesopore structural ordering was confirmed from X-ray diffraction, N-2 physisorption, SEM, and TEM, and the presence and nature of vanadium species inside the framework of the MCM-41 matrix was confirmed in detail with the use of various characterization techniques like FT-IR, Si-29 MAS NMR, DRUV-vis, EPR, V-51 MAS NMR, and Raman analysis. It is deduced from the above characterization techniques that, regardless of the silica source, vanadium is incorporated into the silica framework and thereby increases the structural ordering and wall thickness of the mesoporous material. Thermal and hydrothermal Studies performed over the V-MCM-41 catalysts show that the Si-O-Si inorganic backbone from a fumed silica source is more resistant to severe thermal treatments and hydrolysis than the tetraethyl orthosilicate-synthesized catalysts. Spectroscopic characterization reveals the existence of easily accessible isolated tetrahedral vanadium sites on V-MCM-41 catalyst prepared front fumed silica catalyst, whereas the sample obtained from a tetraethyl orthosilicate silica Source shows vanadium in more disordered sites. Catalytic results show that both catalysts display excellent activity toward the epoxidation reaction of bulkier olefins, and the exceptional activity of the fumed silica catalyst may arise from the more isolated tetrahedral sites and the complementary textural characteristics, which may facilitate the easy access of substrate to the isolated framework metal sites. (c) 2005 Elsevier Inc. All rights reserved.

}, keywords = {epoxidation, fumed silica, MCM-41, tetraethyl orthosilicate, Vanadium}, issn = {0021-9517}, doi = {10.1016/j.jcat.2005.05.001}, author = {Shylesh, S and Singh, AP} } @article { ISI:000240781100009, title = {Effect of spacer groups on the performance of MCM-41-supported platinum cluster-derived hydrogenation catalysts}, journal = {Journal of Catalysis}, volume = {242}, number = {2}, year = {2006}, month = {SEP}, pages = {332-339}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

MCM-41 was functionalized with (EtO)(3)SiCH2Cl, (MeO)(3)SiCH2CH2CH2Cl, and (CH3)Cl2SiCH2Cl. The functionalized materials were characterized by solid-state NMR (CPMAS, Si-29 and C-13) and XPS. The NMR data indicate that three new silicon environments were created by(EtO)(3)SiCH2Cl and (MeO)(3)SiCH2CH2CH2Cl, whereas with (CH3)Cl2SiCH2Cl, two new silicon environments were obtained. XPS results from Si 2p core level and the valence band from the material functionalized by (MeO)(3)Si(CH2)(3)Cl was found to be the same as that of the corresponding fresh catalyst (1a), in contrast to that of the materials functionalized by the other two silane reagents. After further functionalization with triethylamine, these materials were used as inorganic anion exchangers to support the cluster anion [Pt-12(CO)(24)](2-). Solid-state NMR (29Si, C-13, N-15) was used to establish the presence of the quaternary ammonium group in the cluster-supported species. Analogous materials were also created using fumed silica as the support, and all of the cluster-supported materials were tested as catalysts for the hydrogenation of methyl pyruvate, acetophenone, nitrobenzene, benzonitrile, ethylacetoacetate, 4-nitrotoluene, cyclohexanone, allyl alcohol, and styrene. The best activity was obtained for the catalyst that had MCM-41 as the support and chloropropyl as the spacer group. TEM showed that the supports and the spacer groups had observable effects on the platinum crystallite size of the catalysts. (c) 2006 Elsevier Inc. All rights reserved.

}, keywords = {functionalized inorganic oxides, hydrogenation catalysts, MCM-41, platinum carbonyl cluster, Solid-state NMR, spacer groups, XPS}, issn = {0021-9517}, doi = {10.1016/j.jcat.2006.06.016}, author = {Maity, Niladri and Basu, Susmit and Mapa, Maitri and Rajamohanan, Pattuparambil R. and Ganapathy, Subramanian and Gopinath, Chinnakonda S. and Bhaduri, Sumit and Lahiri, Goutam Kumar} } @article { ISI:000234644600023, title = {Hydrothermal synthesis of MCM-41 using differently manufactured amorphous dioxosilicon sources}, journal = {Materials Letters}, volume = {60}, number = {7}, year = {2006}, month = {APR}, pages = {957-961}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The influence of differently manufactured amorphous dioxosilicon sources such as fumed silica (FS), spray dried precipitated silica (PSI) and flash dried precipitated silica (PS,) on the course of structural development and properties of hydrothermally prepared siliceous MCM-41 phases have been investigated. Powder XRD, N-2 adsorption/desorption and scanning electron microscopy techniques were used for sample characterization. On the basis of results obtained from time dependent study on the progressive development of MCM-41 mesophases, the reactivity trend of dioxosilicon sources observed was as: FS \> PS1 \> PS2. MCM-41 synthesized using least expensive PS2 having less surface area has exhibited thicker pore walls but poor orderness, while MCM-41 prepared from expensive FS having high surface area has thinner pore walls and was well ordered. The extent of contraction caused by calcination, magnitude of the wall thickness and structural stability were found to be dependent on manufacturing process of dioxosilicon sources. The noticeable morphological differences were also observed by variations in the type of dioxosilicon sources used in the hydrothermal synthesis MCM-41 materials. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Characterization, dioxosilicon sources, Hydrothermal synthesis, MCM-41, porosity, Structural stability}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.10.049}, author = {Gaydhankar, T. R. and Samuel, V. and Joshi, P. N.} } @article { ISI:000241306300020, title = {Oxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M = Ti, V, Cr): synthesis, characterization and structure-activity correlations}, journal = {Microporous and Mesoporous Materials}, volume = {95}, number = {1-3}, year = {2006}, month = {OCT}, pages = {154-163}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Transition metals (M = Ti, V, Cr) were incorporated into the MCM-41 framework by surfactant-assisted direct hydrothermal (DHT) methods and were characterized in detail by XRD, N-2 adsorption-desorption, TG-DTG/DTA, SEM/TEM, DR UV-Vis, XPS and EPR. The structural regularity as well as the textural properties of the M-MCM-41 materials was confirmed by XRD, TEM and adsorption-desorption techniques. Nature of metal species and the percentage of framework as well as extra framework metal sites in the MCM-41 matrix are discussed in detail by various spectroscopic techniques. The catalytic activity as well as the selectivity of the M-MCM-41 catalysts were explored in the one-step liquid-phase oxidation reaction of ethyl benzene and diphenyl methane. Reaction data showed that the oxidation activity is more when H2O2 was used an oxidant, acetonitrile as solvent and V-MCM-41 as catalyst. However, the selectivity towards the desired keto derivatives (ethyl benzene to acetophenone and diphenyl methane to benzophenone) follows the order, Ti-MCM-41 \> V-MCM-41 \> Cr-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.

}, keywords = {diphenyl methane, Ethyl benzene, MCM-41, Oxidation}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2006.04.018}, author = {Jha, Ratnesh Kumar and Shylesh, S. and Bhoware, Shrikant S. and Singh, A. P.} } @article { ISI:000238111400026, title = {Syntheses of polycarbonate and polyurethane precursors utilizing CO2 over highly efficient, solid as-synthesized MCM-41 catalyst}, journal = {Tetrahedron Letters}, volume = {47}, number = {25}, year = {2006}, month = {JUN}, pages = {4213-4217}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

As-synthesized MCM-41 was used as a reusable, heterogeneous catalyst for the eco-friendly synthesis of cyclic carbonate precursors of polycarbonates via a cycloaddition reaction of CO2 with epoxides. This catalyst is also efficient for the synthesis of alkyl and aryl carbamate precursors of polyurethanes via the reaction of amines, CO2 and alkyl halides. Both these reactions were carried out under mild conditions and without using any solvent or co-catalyst. CO2 is utilized as a raw material replacement for toxic phosgene in the conventional synthesis of these chemicals. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {carbamates, carbon dioxide utilization, CO2 fixation, cyclic carbonates, eco-friendly processes, MCM-41, polycarbonates, polyurethanes}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2006.04.057}, author = {Srivastava, R. and Srinivas, D. and Ratnasamy, P.} } @article { ISI:000239340200010, title = {Synthesis, characterization and optical properties of silver and gold nanowires embedded in mesoporous MCM-41}, journal = {Central European Journal of Chemistry}, volume = {4}, number = {2}, year = {2006}, month = {JUN}, pages = {317-328}, publisher = {SPRINGER HEIDELBERG}, type = {Article}, address = {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY}, abstract = {

Uniform nanowires of silver and gold inside the channels of MCM-41 were prepared by controlled reduction of their respective metal salts with sodium borohydride (NaBH4). Presence of nanowires of silver and gold in MCM-41 were confirmed by high angle X-ray diffraction (XRD) data (peaks between 2 theta = 30 - 60 degrees) and transmission electron microscopy (TEM) confirmed the diameter of the nanowires. Diameter of nanowires is found to be similar to 2.8 nm which is coincident with channel diameter of MCM-41. Optical properties of these heterostructured materials Ag-MCM-41 and Au-MCM-41 reveals the presence of surface plasmon absorption peaks of silver and gold respectively, and the shift in the absorption bands are associated to agglomeration of clusters inside the channels. Room temperature photoluminescence spectra exhibits interesting optical properties as observed for direct band gap semiconductors. Non-linear optical properties (NLO) corresponding to second harmonic generation (SHG) values were also recorded for self supported films of these heterostructured materials. Enhanced optical non-linearity was found to be arising from a corresponding increase of local field near the surface plasmon resonance. Further enhancement in SHG was found with poling due to an induction of orientation order. (C) Versita Warsaw and Springer-Verlag Berlin Heidelberg. All rights reserved.

}, keywords = {Ag/Au nanowires, MCM-41, photoluminescence, SHG, TEM}, issn = {1895-1066}, doi = {10.2478/s11532-006-0006-4}, author = {Adhyapak, Parag V. and Karandikar, Prashant R. and Dadge, Jagdish W. and Aiyer, Rohini C. and Chandwadkar, Asha J.} } @article { ISI:000244183400015, title = {Tungstophosphoric acid supported over zirconia in mesoporous channels of MCM-41 as catalyst in veratrole acetylation}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {262}, number = {1-2}, year = {2007}, month = {FEB}, pages = {98-108}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Tungstophosphoric acid (TPA) over zirconia dispersed uniformly in mesoporous silica (MS) channels of MCM-41 and MCM-48 were synthesized and tested for their catalytic activity in veratrole acetylation. Catalysts with different TPA loadings (5-50 wt.\%) on 22.4 wt.\%ZrO2/MCM-41 and 15 wt.\%TPA on different zirconia loadings (10-70 wt.\%)/MCM-41 were prepared and calcined at 1123 K. The physico-chemical characterization of the supported catalysts was done by powder X-ray diffraction (XRD), surface area measurement (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed-infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectra, Temperature programmed desorption (TPD) of ammonia, FT-IR pyridine adsorption and (31) P cross polarization-magic angle spinning (CP-MAS) NMR spectroscopy. The mesoporous silica supports play an important role in stabilizing catalytically active TPA along with tetragonal phase of zirconia. Among the catalysts, 15 wt.\%TPA/22.4 wt.\%ZrO2/MCM-41 calcined at 1123 K was found to have highest acidity and at least four times more active than neat 15 wt.\%TPA/ZrO2 in veratrole acetylation to acetoveratrone by acetic anhydride. Reaction conditions were evaluated with 15 wt.\%TPA/22.4 wt:\%ZrO2/MCM-41 calcined at 1123 K to get higher conversion of acetic anhydride to acetoveratrone. The reaction was found to be heterogeneously catalyzed and no contribution from homogeneous (leached) TPA into the medium under the reaction conditions. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {acetoveratrone, acetylation, MCM-41, TPA/ZrO2, veratrole}, issn = {1381-1169}, doi = {10.1016/j.molcata.2006.08.027}, author = {Sawant, Dhanashri P. and Vinu, A. and Lefebvre, F. and Halligudi, Shivaraj B.} } @article { ISI:000252529400004, title = {Bridging the gap between micropores and mesopores by the controlled transformation of bifunctional periodic mesoporous silicas}, journal = {Microporous and Mesoporous Materials}, volume = {108}, number = {1-3}, year = {2008}, month = {FEB}, pages = {29-40}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Novel bifunctional periodic mesoporous silicas having high content of organic groups in the pore channels and chromium in the frame wall has been synthesized by direct co-condensation method, using organo trialkoxysilanes (chloro propyl, vinyl, methyl), chromium nitrate and tetraethyl orthosilicate, in presence of cetyltrimethyl ammonium surfactants. The obtained materials show one main peak in the XRD patterns up to a molar ratio of 1: 1 between TEOS and organosilane in the synthesis gel and N-2 adsorption-desorption analysis shows that the mesopore structure remains intact after the surfactant removal process. Among the organosilanes, chloro propyl and vinyl pendant chromium samples shows a shift in the main peak to higher 2-theta values with a corresponding decrease in pore volume and pore diameter, with the percentage of organosilane functionalization. Small-pore silicas and chromium silicas can be prepared from the large pore mesoporous MCM-41, by effectively removing the organic groups by calcination. By this method, the pore size of the material can be tailored into the super-microporous region, without changing the chain length of the surfactant used in the assembly process. The shrinkage in pore size is dependent on the nature and percentage of the organic pendant groups that the chloro propyl and vinyl pendant mesoporous materials show the maximum pore size shrinkage than the small chain length methyl units. Because of the tailorable pore size and with better textural characteristics, chromium-silica materials find applications in the field of shape selective heterogeneous catalysis, as demonstrated in the oxidation reaction of cyclohexane, than the conventional metal-containing mesoporous materials. (c) 2007 Elsevier Inc. All rights reserved.

}, keywords = {bifunctional silicas, chromium, Cyclohexane, MCM-41, Oxidation}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2007.03.039}, author = {Shylesh, S. and Srilakshini, Ch. and Singh, A. P. and Anderson, B. G.} } @article { ISI:000271443200015, title = {Catalytic activity of cobalt containing MCM-41 and HMS in liquid phase oxidation of diphenylmethane}, journal = {Catalysis Letters}, volume = {133}, number = {1-2}, year = {2009}, month = {NOV}, pages = {106-111}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Cobalt containing MCM-41 and HMS were synthesized by direct hydrothermal (DHT) and post synthesis methods (grafting and immobilization). The catalytic activity of these materials was investigated in the liquid phase oxidation of diphenylmethane at 80 A degrees C with TBHP (70 wt\%) as oxidant. Comparative study of cobalt containing MCM-41 and HMS was carried out to reveal the catalytic performance of framework, extraframework and immobilized cobalt species. The role of the solvent in the performance of catalyst was examined with different polar and non polar solvents. Oxidation of diphenylmethane in solvent free media (under similar reaction conditions) shows formation of hydroxy derivatives of benzophenone in addition to main product (benzophenone). Hundred percent selectivity to benzophenone was obtained when the reaction was carried out in solvent.

}, keywords = {diphenylmethane, HMS, Immobilization, MCM-41, XRD}, issn = {1011-372X}, doi = {10.1007/s10562-009-0162-1}, author = {Bhoware, Shrikant S. and Kamble, K. R. and Singh, A. P.} } @article { ISI:000263509700027, title = {Selective oxidation of benzyl alcohol over copper phthalocyanine immobilized on MCM-41}, journal = {Catalysis Letters}, volume = {128}, number = {3-4}, year = {2009}, month = {MAR}, pages = {434-442}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Copper phthalocyanine (CuPc) complexes immobilized on {\textquoteleft}{\textquoteleft}neat{\textquoteright}{\textquoteright} and Ti(4+) and Al(3+) containing MCM-41 mimic the functionality of metalloenzymes. These novel materials catalyze the oxidation of benzyl alcohol to selectively benzaldehyde at moderate temperatures using peroxides and molecular oxygen as oxidant. Electron paramagnetic resonance and X-ray photoelectron spectroscopic studies revealed that the acidity of the support (MCM-41) influences the electronic structure of the immobilized CuPc. On acidic supports a part of copper in CuPc got reduced from a {\textquoteleft}{\textquoteleft}formal{\textquoteright}{\textquoteright} +2 to +1 oxidation state. This reduction of copper in its oxidation state on different supports decreased in the order: Al-MCM-41 (Bronsted and strong Lewis acid sites) \> MCM-41 (silanol sites) \> Ti-MCM-41 (weak Lewis acid sites). A linear variation in catalytic activity with the concentration of Cu(1+) ions in different catalyst samples was observed. The study reveals that by suitably modifying the acidic properties of the support one can, in principle, fine-tune the electronic and catalytic properties of the active oxidation sites.

}, keywords = {Copper phthalocyanine, EPR, MCM-41, Selective oxidation of benzyl alcohol, UV-visible spectroscopy}, issn = {1011-372X}, doi = {10.1007/s10562-008-9770-4}, author = {Hamza, A. and Srinivas, D.} } @article { ISI:000291421400015, title = {Selective hydrogenation of chloronitrobenzenes with an MCM-41 supported platinum allyl complex derived catalyst}, journal = {Applied Catalysis A-General}, volume = {399}, number = {1-2}, year = {2011}, month = {MAY}, pages = {117-125}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A platinuin precatalyst (1) has been prepared by reacting [(eta(3)-C3H5)(4)Pt4Cl4] with surface functionalized MCM-41 with pendant -(CH2)(3)NH(CH2)(2)NH2 groups. For the hydrogenation of o-, m- and p-chloronitrobenzenes to the corresponding chloroanilines, 1 is found to be a highly active catalyst with good selectivities for them-and p-isomers. Its performance is superior to that of its palladium analogue and far superior to that of commercial (5\%) Pt/C or (5\%) Pt/Al2O3. Comparison of solid state and solution NMR data and other evidences indicate that on treatment with the functionalized MCM-41 support; [(eta(3)-C3H5)(4)Pt4Cl4] loses the ally! ligand. XPS data show that in the fresh catalyst Pt is present in the 2+ oxidation state. Based on these and analytical data, co-ordination by surface diamine and hydroxo groups to Pt2+ in 1 is suggested. In the used catalyst both Pt2+ and Pt are present but the amount of metallic platinum is similar to 16\% of the total. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Chloronitrobenzenes, Dehydrohalogenation, heterogeneous catalyst, MCM-41, Selective hydrogenation}, issn = {0926-860X}, doi = {10.1016/j.apcata.2011.03.044}, author = {Indra, Arindam and Rajamohanan, Pattuparambil R. and Gopinath, Chinnakonda S. and Bhaduri, Sumit and Lahiri, Goutam Kumar} } @article {43957, title = {Cascade synthesis of dihydrobenzofuran via claisen rearrangement of allyl aryl ethers using FeCl 3 /MCM-41 catalyst}, journal = {Journal of Saudi Chemical Society}, volume = {22}, year = {2018}, month = {MAY}, pages = {396-404}, type = {Article}, abstract = {

Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III) chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Br{\o}nsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71-86\%.

}, keywords = {Aryl allyl ether, Claisen rearrangement, Dihydrobenzofuran, Ferric chloride, MCM-41}, issn = {1319-6103}, doi = {10.1016/j.jscs.2017.08.006}, author = {Sakate, Sachin S. and Shinde, Suhas H. and Kasar, Gayatri B. and Chikate, Rajeev C. and Rode, Chandrashekhar V.} }