01967nas a2200229 4500008004100000022001400041245010400055210006900159260007300228300001000301490000800311520116300319653001401482653001101496653001501507653001401522653001301536100001601549700002601565700001801591856012801609 2005 eng d a1381-116900aInfluence of silica source in the catalytic activity and heterogenity of mesoporous vanadosilicates0 aInfluence of silica source in the catalytic activity and heterog aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP a57-630 v2393 a

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.

10a1-napthol10aMCM-4110aMesoporous10aOxidation10aVanadium1 aShylesh, S.1 aMirajkar, Subhash, P.1 aSingh, A., P. uhttps://library.ncl.res.in/content/influence-silica-source-catalytic-activity-and-heterogenity-mesoporous-vanadosilicates-002179nas a2200229 4500008004100000022001400041245013600055210006900191260007300260300001200333490000800345520133700353653001301690653001701703653001101720653003201731653001301763100001501776700001501791700001401806856012901820 2005 eng d a0926-860X00aVanadium-containing ordered mesoporous silicas: synthesis, characterization and catalytic activity in the hydroxylation of biphenyl0 aVanadiumcontaining ordered mesoporous silicas synthesis characte aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG a148-1580 v2903 a

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.

10abiphenyl10aheterogenity10aMCM-4110aMesoporous molecular sieves10aVanadium1 aGeorge, J.1 aShylesh, S1 aSingh, AP uhttps://library.ncl.res.in/content/vanadium-containing-ordered-mesoporous-silicas-synthesis-characterization-and-catalytic-002615nas a2200217 4500008004100000022001400041245017900055210006900234260009500303300001200398490000800410520174100418653001602159653001702175653001102192653002902203653001302232100001502245700001402260856012302274 2005 eng d a0021-951700aVanadium-containing ordered mesoporous silicates: does the silica source really affect the catalytic activity, structural stability, and nature of vanadium sites in V-MCM-41?0 aVanadiumcontaining ordered mesoporous silicates does the silica  a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcJUL a359-3710 v2333 a

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.

10aepoxidation10afumed silica10aMCM-4110atetraethyl orthosilicate10aVanadium1 aShylesh, S1 aSingh, AP uhttps://library.ncl.res.in/content/vanadium-containing-ordered-mesoporous-silicates-does-silica-source-really-affect-002690nas a2200313 4500008004100000022001400041245011600055210006900171260009500240300001200335490000800347520155000355653003601905653002801941653001101969653003001980653002002010653001802030653000802048100001902056700001702075700001702092700003502109700002702144700003002171700001902201700002602220856013002246 2006 eng d a0021-951700aEffect of spacer groups on the performance of MCM-41-supported platinum cluster-derived hydrogenation catalysts0 aEffect of spacer groups on the performance of MCM41supported pla a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcSEP a332-3390 v2423 a

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.

10afunctionalized inorganic oxides10ahydrogenation catalysts10aMCM-4110aplatinum carbonyl cluster10aSolid-state NMR10aspacer groups10aXPS1 aMaity, Niladri1 aBasu, Susmit1 aMapa, Maitri1 aRajamohanan, Pattuparambil, R.1 aGanapathy, Subramanian1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttps://library.ncl.res.in/content/effect-spacer-groups-performance-mcm-41-supported-platinum-cluster-derived-hydrogenation-102121nas a2200241 4500008004100000022001400041245009900055210006900154260007300223300001200296490000700308520126100315653002101576653002501597653002701622653001101649653001301660653002501673100002301698700001501721700001801736856012501754 2006 eng d a0167-577X00aHydrothermal synthesis of MCM-41 using differently manufactured amorphous dioxosilicon sources0 aHydrothermal synthesis of MCM41 using differently manufactured a aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a957-9610 v603 a

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.

10aCharacterization10adioxosilicon sources10aHydrothermal synthesis10aMCM-4110aporosity10aStructural stability1 aGaydhankar, T., R.1 aSamuel, V.1 aJoshi, P., N. uhttps://library.ncl.res.in/content/hydrothermal-synthesis-mcm-41-using-differently-manufactured-amorphous-dioxosilicon-002025nas a2200229 4500008004100000022001400041245016600055210006900221260007300290300001200363490000700375520113600382653002101518653001801539653001101557653001401568100002401582700001601606700002601622700001801648856012901666 2006 eng d a1387-181100aOxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M = Ti, V, Cr): synthesis, characterization and structure-activity correlations0 aOxidation of ethyl benzene and diphenyl methane over ordered mes aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a154-1630 v953 a

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.

10adiphenyl methane10aEthyl benzene10aMCM-4110aOxidation1 aJha, Ratnesh, Kumar1 aShylesh, S.1 aBhoware, Shrikant, S.1 aSingh, A., P. uhttps://library.ncl.res.in/content/oxidation-ethyl-benzene-and-diphenyl-methane-over-ordered-mesoporous-m-mcm-41-m-ti-v-cr-001626nas a2200265 4500008004100000022001400041245013300055210006900188260010600257300001400363490000700377520063300384653001501017653003101032653001701063653002201080653002701102653001101129653001901140653001801159100001901177700001701196700001801213856012901231 2006 eng d a0040-403900aSyntheses of polycarbonate and polyurethane precursors utilizing CO2 over highly efficient, solid as-synthesized MCM-41 catalyst0 aSyntheses of polycarbonate and polyurethane precursors utilizing aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN a4213-42170 v473 a

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.

10acarbamates10acarbon dioxide utilization10aCO2 fixation10acyclic carbonates10aeco-friendly processes10aMCM-4110apolycarbonates10apolyurethanes1 aSrivastava, R.1 aSrinivas, D.1 aRatnasamy, P. uhttps://library.ncl.res.in/content/syntheses-polycarbonate-and-polyurethane-precursors-utilizing-co2-over-highly-efficient-002316nas a2200253 4500008004100000022001400041245011400055210006900169260008000238300001200318490000600330520140700336653002001743653001101763653002201774653000801796653000801804100002401812700002901836700002301865700002201888700002601910856012601936 2006 eng d a1895-106600aSynthesis, characterization and optical properties of silver and gold nanowires embedded in mesoporous MCM-410 aSynthesis characterization and optical properties of silver and  aTIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANYbSPRINGER HEIDELBERGcJUN a317-3280 v43 a

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.

10aAg/Au nanowires10aMCM-4110aphotoluminescence10aSHG10aTEM1 aAdhyapak, Parag, V.1 aKarandikar, Prashant, R.1 aDadge, Jagdish, W.1 aAiyer, Rohini, C.1 aChandwadkar, Asha, J. uhttps://library.ncl.res.in/content/synthesis-characterization-and-optical-properties-silver-and-gold-nanowires-embedded-002438nas a2200241 4500008004100000022001400041245012100055210006900176260007300245300001100318490000800329520157000337653001901907653001601926653001101942653001301953653001401966100002601980700001302006700001702019700002802036856013202064 2007 eng d a1381-116900aTungstophosphoric acid supported over zirconia in mesoporous channels of MCM-41 as catalyst in veratrole acetylation0 aTungstophosphoric acid supported over zirconia in mesoporous cha aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a98-1080 v2623 a

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.

10aacetoveratrone10aacetylation10aMCM-4110aTPA/ZrO210averatrole1 aSawant, Dhanashri, P.1 aVinu, A.1 aLefebvre, F.1 aHalligudi, Shivaraj, B. uhttps://library.ncl.res.in/content/tungstophosphoric-acid-supported-over-zirconia-mesoporous-channels-mcm-41-catalyst-veratrole02664nas a2200241 4500008004100000022001400041245013100055210006900186260007300255300001000328490000800338520179500346653002502141653001302166653001602179653001102195653001402206100001602220700002102236700001802257700002102275856012602296 2008 eng d a1387-181100aBridging the gap between micropores and mesopores by the controlled transformation of bifunctional periodic mesoporous silicas0 aBridging the gap between micropores and mesopores by the control aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a29-400 v1083 a

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.

10abifunctional silicas10achromium10aCyclohexane10aMCM-4110aOxidation1 aShylesh, S.1 aSrilakshini, Ch.1 aSingh, A., P.1 aAnderson, B., G. uhttps://library.ncl.res.in/content/bridging-gap-between-micropores-and-mesopores-controlled-transformation-bifunctional-001670nas a2200229 4500008004100000022001400041245010400055210006900159260005700228300001200285490000800297520087400305653002001179653000801199653001901207653001101226653000801237100002601245700001901271700001801290856013201308 2009 eng d a1011-372X00aCatalytic activity of cobalt containing MCM-41 and HMS in liquid phase oxidation of diphenylmethane0 aCatalytic activity of cobalt containing MCM41 and HMS in liquid  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcNOV a106-1110 v1333 a

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.

10adiphenylmethane10aHMS10aImmobilization10aMCM-4110aXRD1 aBhoware, Shrikant, S.1 aKamble, K., R.1 aSingh, A., P. uhttps://library.ncl.res.in/content/catalytic-activity-cobalt-containing-mcm-41-and-hms-liquid-phase-oxidation-diphenylmethane-001909nas a2200217 4500008004100000022001400041245009100055210006900146260005700215300001200272490000800284520113100292653002601423653000801449653001101457653004201468653002801510100001401538700001701552856012201569 2009 eng d a1011-372X00aSelective oxidation of benzyl alcohol over copper phthalocyanine immobilized on MCM-410 aSelective oxidation of benzyl alcohol over copper phthalocyanine a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcMAR a434-4420 v1283 a

Copper phthalocyanine (CuPc) complexes immobilized on ``neat'' 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 ``formal'' +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.

10aCopper phthalocyanine10aEPR10aMCM-4110aSelective oxidation of benzyl alcohol10aUV-visible spectroscopy1 aHamza, A.1 aSrinivas, D. uhttps://library.ncl.res.in/content/selective-oxidation-benzyl-alcohol-over-copper-phthalocyanine-immobilized-mcm-41-001985nas a2200253 4500008004100000022001400041245011600055210006900171260007300240300001200313490000800325520103000333653002401363653002401387653002701411653001101438653002801449100001901477700003501496700003001531700001901561700002601580856012501606 2011 eng d a0926-860X00aSelective hydrogenation of chloronitrobenzenes with an MCM-41 supported platinum allyl complex derived catalyst0 aSelective hydrogenation of chloronitrobenzenes with an MCM41 sup aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a117-1250 v3993 a

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.

10aChloronitrobenzenes10aDehydrohalogenation10aheterogeneous catalyst10aMCM-4110aSelective hydrogenation1 aIndra, Arindam1 aRajamohanan, Pattuparambil, R.1 aGopinath, Chinnakonda, S.1 aBhaduri, Sumit1 aLahiri, Goutam, Kumar uhttps://library.ncl.res.in/content/selective-hydrogenation-chloronitrobenzenes-mcm-41-supported-platinum-allyl-complex-001723nas a2200253 4500008004100000022001400041245012000055210006900175260000800244300001200252490000700264520084500271653002101116653002601137653002201163653002001185653001101205100002301216700002201239700002301261700002401284700002901308856013201337 2018 eng d a1319-610300aCascade synthesis of dihydrobenzofuran via claisen rearrangement of allyl aryl ethers using FeCl 3 /MCM-41 catalyst0 aCascade synthesis of dihydrobenzofuran via claisen rearrangement cMAY a396-4040 v223 a

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 Brønsted 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%.

10aAryl allyl ether10aClaisen rearrangement10aDihydrobenzofuran10aFerric chloride10aMCM-411 aSakate, Sachin, S.1 aShinde, Suhas, H.1 aKasar, Gayatri, B.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V. uhttps://library.ncl.res.in/content/cascade-synthesis-dihydrobenzofuran-claisen-rearrangement-allyl-aryl-ethers-using-fecl-3-mcm02471nas a2200277 4500008004100000022001400041245014400055210006900199260000800268300001200276490000700288520152400295653001001819653001101829653003801840653001701878653002101895653002501916653001101941653002101952653003001973100001702003700002202020700002802042856012302070 2025 eng d a1022-552800aUltra-small Pd nanoparticles on SBA-15: an efficient catalyst for one-pot reductive alkylation of nitrobenzene with size-dependent activity0 aUltrasmall Pd nanoparticles on SBA15 an efficient catalyst for o cFEB a414-4290 v683 a

One-pot reductive alkylation of nitrobenzene with alcohol is an important organic synthesis reaction to form 2 degrees amines. In the present work, we have demonstrated that Pd/SBA-15 can be an effective catalytic system for this reaction. We have designed ultra-small Pd nanoparticles supported on SBA-15 for the synthesis of secondary amine, N-ethylaniline, through one-pot reductive alkylation of nitrobenzene with ethanol under ambient conditions. Ethanol functions both as the alkylating agent and the solvent in this process. The reaction is driven by the simultaneous hydrogenation of nitrobenzene to aniline, dehydrogenation of ethanol to aldehyde, and condensation of aniline and acetaldehyde to form N-ethylaniline. The size of the Pd nanoparticles plays a decisive role in the product selectivity. The undercoordinated sites present on ultra-small Pd NPs can facilitate ethanol dehydrogenation to acetaldehyde, thereby enhancing the selectivity towards N-ethylaniline compared to larger Pd nanoparticles. We have also studied the effect of different mesoporous supports such as SBA-15, MCM-41, and KIT-6 on the N-ethylaniline selectivity and found that SBA-15 was most selective. We have demonstrated that by carefully designing the catalyst such as controlling the Pd NPs size to obtain the maximum quantity of undercoordinated sites and choosing suitable support, the aliphatic alcohols can also be used for reductive alkylation of nitrobenzene in one-pot with optimum yields of N-alkylaniline.

10aKIT-610aMCM-4110aModified deposition precipitation10anitrobenzene10aPd nanoparticles10aReductive alkylation10aSBA-1510asecondary amines10aUndercoordinated Pd sites1 aSoni, Yogita1 aPhilip, Milda, C.1 aVinod, Chathakudath, P. uhttps://library.ncl.res.in/content/ultra-small-pd-nanoparticles-sba-15-efficient-catalyst-one-pot-reductive-alkylation