02717nas a2200301   4500008004100000022001400041245010700055210006900162260007300231300001200304490000800316520171400324653001202038653001802050653002302068653001002091653000702101653001302108653002002121653001802141653002302159100001802182700001602200700002802216700001802244700003002262856012302292       2005                        eng d  a1381-116900aInsight into the mechanism of selective mono-N-methylation of aniline on Cu1-xZnxFe2O4: a DRIFTS study0 aInsight into the mechanism of selective monoNmethylation of anil  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR  a169-1800 v2313 a<p>Mechanism of selective mono-N-methylation of aniline with methanol on Cu1-xZn2FeO4 catalysts was investigated in detail. The interaction of reactants (aniline. methanol and methanol: aniline) and possible products (N-methylaniline (NMA), N,N-dimethylaniline (DMA) and o-toluidine (OT)) on catalysts surface was studied by temperature-dependent in situ FTIR spectroscopy. Methanol adsorbs dissociatively over catalysts surface at 373 K as methoxy species and is oxidized to formate species at high temperature through dioxymethylene and/or formaldehyde as a surface intermediate species. On the other hand, adsorption of aniline:methanol mixtures shows that methanol oxidation was completely hindered in the presence of aniline. Aniline adsorbs on the Lewis acid sites at &lt;= 373 K with phenyl ring oriented in a perpendicular manner to the catalyst surfaced however, N-H bond scission occurs above 373 K. A comparison of adsorbed NMA and methanol: am line (3:1) mixture on Cu0.5Zn0.5Fe2O4 shows NMA forms from the reaction mixture at 473 K. However, maximum activity at 573 K in catalytic reaction studies suggests that desorption limits the methylation kinetics. FTIR study displays stable aniline and methyl species on ZnFe2O4 even at 573 K; however. no methyl species is detected on Cr0.95Zn0.05Fe2O4 at 473 K due to methanol reforming reaction and that limits the overall reaction and hence low catalytic activity. It is proposed that methanol is protonated on catalysts surface by the labile H+ due to N-H bond scission. Co-adsorption of acidity probes with aniline and methanol indicates that aniline methylation takes place at single acid-base site. (c) 2005 Elsevier B.V. All rights reserved.</p>10aAniline10aCu1-xZnxFe2O410adesorption limited10aDRIFT10aIR10aMethanol10aN-methylaniline10aN-methylation10areaction mechanism1 aVijayaraj, M.1 aMurugan, B.1 aUmbarkar, Shubhangi, B.1 aHegde, S., G.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/insight-mechanism-selective-mono-n-methylation-aniline-cu1-xznxfe2o4-drifts-study-002485nas a2200241   4500008004100000022001400041245014800055210006900203260007700272300001400349490000600363520154400369653002901913653002801942653001501970653001201985653002201997100002402019700002402043700002802067700002302095856012502118       2013                        eng d  a1867-388000aIsolation, characterization, and identification of catalytically active species in the MoO3/SiO2 catalyst during solid acid catalyzed reactions0 aIsolation characterization and identification of catalytically a  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUN  a1531-15370 v53 a<p>We report the isolation, characterization, and identification of the catalytically active species formed during various acid-catalyzed reactions if silica-supported MoO3 was used as a catalyst. We have reported previously the synthesis and extensive characterization of the silica-supported MoO3 catalyst prepared by the sol-gel process with ammonium heptamolybdate and ethyl silicate-40 as molybdenum and silica precursors, respectively. The TEM images showed uniformly distributed MoO3 nanoparticles on the high-surface area mesoporous silica support and high acidity (0.9mmolg-1) by using temperature-programmed desorption of ammonia (NH3-TPD) analysis. This catalyst has already shown high activity for various acid-catalyzed reactions. To understand the nature of catalytically active species formed during the reaction, the liquid-phase esterification of acetic acid and ethanol was studied as a probe reaction with very high acid conversion (83%) in 8h. During esterification, the reaction mixture turned blue, which indicated a change in the nature of the catalyst under reaction conditions. These catalytically active species formed in the reaction mixture were isolated and extensively characterized by using FTIR, Raman, powder XRD, BET surface area, NH3-TPD, energy dispersive X-ray, and TEM analysis. The characterization results revealed the insitu formation of silicomolybdic acid on the silica surface in the presence of water, which acts as catalytically active species responsible for the acid-catalyzed reactions.</p>10aesterification reactions10aheterogeneous catalysis10aMolybdenum10asilicon10asol-gel processes1 aKotbagi, Trupti, V.1 aBiradar, Ankush, V.1 aUmbarkar, Shubhangi, B.1 aDongare, Mohan, K.  uhttps://library.ncl.res.in/content/isolation-characterization-and-identification-catalytically-active-species-moo3sio2-0