- Email: [email protected]
23-P-12 - Mechanistic study of aniline methylation over acidic and basic zeolites Y
232
23-P-12 - Mechanistic study of aniline methylation over acidic and basic zeolites Y I.I. Ivanova (a), E.B. Pomakhina (a), A.I. Rebrov (b), Y.G. Kolyagin (a), M. Hunger (c) and J. Weitkamp (c) a Moscow State University, Moscow 119899, e-mail. [email protected] b Institute of Petrochemical Synthesis, RAS, Leninsky pr. 29, 117012 Moscow, Russia c Institute of Chemical Technology, University of Stuttgart, D-70550 Stuttgart, Germany 13C MAS NMR has been performed in-situ under batch conditions to investigate the mechanism of aniline alkylation with methanol on acidic H-Y and basic CsNa-Y impregnated with cesium hydroxide. On acidic zeolite H-Y, methanol reacts with zeolitic hydroxyl groups to give surface methoxy groups which, in turn, play a role as alkylating species in aniline methylation. On the basic zeolite Y, methanol is converted into formaldehyde, which is responsible for the Nalkylation. Both on acidic and basic zeolites, N-methylaniline is the primary alkylation product. Toluidines and N-methyltoluidines are formed only on the acidic zeolite at elevated temperatures after complete conversion of methanol into N-methylaniline.
23-P-13 - Heterogeneous base catalysis: characterization of zeolites and mixed oxides using nitromethane as a N M R probe molecule and activity in the Michai~i condensation of nitromethane and cyclohex-2-en-l-one E. Lima, L.-C. de Mtnorval, M. Lasptras, J.-F. Eckhard, D. Tichit, P. Graffin and F. Fajula Ecole Nationale Sup6rieure de Chimie de Montpellier, [email protected] The use of nitromethane as a probe of basicity of zeolites (NaX, CsX, CsX 9Cs) and mixed oxides, Mg(AI)O, is discussed. Various species (physisorbed nitromethane, aci-anion nitromethane, and methazonate salt analogue) formed upon nitromethane adsorption were characterized by 13C MAS NMR spectroscopy. Heterogeneous base catalysis of the Michael addition of nitromethane on cyclohex-2-en-l-one was also studied. Low rates were obtained for catalysts showing only nitromethane physisorption. Formation of aci-anion nitromethane was observed for solids of medium efficiency; correlation of the chemical shift with the initial rate was established. Finally, the decrease of Lewis acidity and concomitant increase of basicity led to methazonate formation and to the more efficient catalysts.
23-P-14 - Synthesis molecular sieves
of ot-pinene
derivatives
using
redox-mesoporous
Y.-W. Suh (a), T.-M. Son (a), N.-K. Kim (b), W.-S. Ahn (b) and H.-K. Rhee* (a) a School of Chemical Engineering and Institute of Chemical Processes, Seoul National University, Kwanak-ku, Seoul 151-742, [email protected], Kore a b School of Chemical Science and Engineering, Inha University, Inchon 402-751, Korea Ti-HMS catalyst was successfully used as a bifunctional catalyst for the one-step conversion of a-pinene to campholenic aldehyde.
23-P-12 - Mechanistic study of aniline methylation over acidic and basic zeolites Y I.I. Ivanova (a), E.B. Pomakhina (a), A.I. Rebrov (b), Y.G. Kolyagin (a), M. Hunger (c) and J. Weitkamp (c) a Moscow State University, Moscow 119899, e-mail. [email protected] b Institute of Petrochemical Synthesis, RAS, Leninsky pr. 29, 117012 Moscow, Russia c Institute of Chemical Technology, University of Stuttgart, D-70550 Stuttgart, Germany 13C MAS NMR has been performed in-situ under batch conditions to investigate the mechanism of aniline alkylation with methanol on acidic H-Y and basic CsNa-Y impregnated with cesium hydroxide. On acidic zeolite H-Y, methanol reacts with zeolitic hydroxyl groups to give surface methoxy groups which, in turn, play a role as alkylating species in aniline methylation. On the basic zeolite Y, methanol is converted into formaldehyde, which is responsible for the Nalkylation. Both on acidic and basic zeolites, N-methylaniline is the primary alkylation product. Toluidines and N-methyltoluidines are formed only on the acidic zeolite at elevated temperatures after complete conversion of methanol into N-methylaniline.
23-P-13 - Heterogeneous base catalysis: characterization of zeolites and mixed oxides using nitromethane as a N M R probe molecule and activity in the Michai~i condensation of nitromethane and cyclohex-2-en-l-one E. Lima, L.-C. de Mtnorval, M. Lasptras, J.-F. Eckhard, D. Tichit, P. Graffin and F. Fajula Ecole Nationale Sup6rieure de Chimie de Montpellier, [email protected] The use of nitromethane as a probe of basicity of zeolites (NaX, CsX, CsX 9Cs) and mixed oxides, Mg(AI)O, is discussed. Various species (physisorbed nitromethane, aci-anion nitromethane, and methazonate salt analogue) formed upon nitromethane adsorption were characterized by 13C MAS NMR spectroscopy. Heterogeneous base catalysis of the Michael addition of nitromethane on cyclohex-2-en-l-one was also studied. Low rates were obtained for catalysts showing only nitromethane physisorption. Formation of aci-anion nitromethane was observed for solids of medium efficiency; correlation of the chemical shift with the initial rate was established. Finally, the decrease of Lewis acidity and concomitant increase of basicity led to methazonate formation and to the more efficient catalysts.
23-P-14 - Synthesis molecular sieves
of ot-pinene
derivatives
using
redox-mesoporous
Y.-W. Suh (a), T.-M. Son (a), N.-K. Kim (b), W.-S. Ahn (b) and H.-K. Rhee* (a) a School of Chemical Engineering and Institute of Chemical Processes, Seoul National University, Kwanak-ku, Seoul 151-742, [email protected], Kore a b School of Chemical Science and Engineering, Inha University, Inchon 402-751, Korea Ti-HMS catalyst was successfully used as a bifunctional catalyst for the one-step conversion of a-pinene to campholenic aldehyde.