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-0