@article { ISI:000266185600012, title = {Selective N-alkylation of aniline with methanol over a heteropolyacid on montmorillonite K10}, journal = {Applied Clay Science}, volume = {44}, number = {3-4}, year = {2009}, month = {MAY}, pages = {255-258}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

N-methylaniline is an industrially important product in the manufacture of paper, textile dyes, drugs, perfumes and explosives. The vapour phase alkylation of aniline with methanol forming N-methylaniline is advantageous over liquid phase alkylation. In present study, vapour phase methylation of aniline over dodecatungestophosphoric acid supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out. The 20\% m/m DTPA/K10 was found to be optimum with 79\% aniline conversion and 99\% N-methylaniline selectivity. The reaction required milder operating conditions than reported for commercial catalysts. We also studied the feasibility of 20\% m/m DTPA/K10 as a catalyst for the alkylation of aniline with other alcohols like ethanol, n-propanol, iso-propanol and n-butanol. The activity of 20\% m/m DTPA/K10 decreased with increasing carbon number. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Alkylation, Aniline, Heteropolyacid, montmorillonite K10, N-methylaniline}, issn = {0169-1317}, doi = {10.1016/j.clay.2009.02.011}, author = {Nehate, Manoj and Bokade, Vijay V.} } @article { ISI:000271443200024, title = {Synthesis of N-methylaniline by aniline alkylation with methanol over Sn-MFI molecular sieve}, journal = {Catalysis Letters}, volume = {133}, number = {1-2}, year = {2009}, month = {NOV}, pages = {175-184}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Sn-MFI molecular sieves (Tin silicalite-1) with SiO(2)/SnO(2) molar ratio of 50-150 were synthesized and characterized. Elemental analysis, XRD and DRUV-vis confirmed that prepared samples were of MFI zeolite structure and Sn was incorporated in MFI framework. Vapor phase methylation of aniline over Sn-MFI was systematically studied and optimizations of process parameters were carried out. Sn-MFI (SiO(2)/SnO(2) = 50) was found to be optimum catalyst with 55\% aniline conversion and 60\% N-methylaniline selectivity. At lower space velocity (higher contact time) of 1 h(-1), aniline conversion was found to be increased to 71\% with reduction in N-methylaniline selectivity to 39\% and increased in N,N-dimethylaniline selectivity to 58\%. The reaction follows first order kinetics with respect to aniline having activation energy of 7.3 kcal/mol.

}, keywords = {Aniline, Lewis acid, Methanol, N-methylaniline, Sn-MFI}, issn = {1011-372X}, doi = {10.1007/s10562-009-0143-4}, author = {Niphadkar, P. S. and Joshi, P. N. and Gurav, H. R. and Deshpande, Suvarna S. and Bokade, Vijay V.} } @article { ISI:000293492300024, title = {Influence of Al3+ insertion in the stannosilicate MFI framework on the catalytic performance in vapor phase aniline N-methylation}, journal = {Applied Catalysis A-General}, volume = {401}, number = {1-2}, year = {2011}, month = {JUL}, pages = {182-188}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Silica-based Sn-MFI, Al-MFI and Al-Sn-MFI molecular sieves were synthesized by hydrothermal crystallization of gels having molar compositions SiO2:xSnO(2):yAl(2)O(3):0.23 (TPA)(2)O:35H(2)O, where x ranges from 1/0 to 1/200 and y from 1/0 to 1/400. Keeping molar Si/(Al + Sn) = 50, the amount of tin and aluminum in hydrogel was varied (Sn:Al molar ratios = 1:0, 1:0.33, 1:1, 1:3, 0:1) to investigate the synergy between Lewis and Bronsted acid sites in acid catalyzed aniline N-methylation reaction. Catalyst characterization was done by Powder X-ray diffraction, DRUV-vis spectroscopy, temperature programmed ammonia desorption (TPAD) and FTIR spectroscopy. An increase in the Al3+ insertion in Sn-MFI framework resulted in the increase in the stronger acid sites. Al-Sn-MFI showed higher aniline conversion than their monometallic counterparts. A sample having B/L ratio in between 0.67 and 0.91 was found to be optimum for maximizing the NMA yield, indicating the existence synergistic properties of Al-Sn-MFI. Upon process parameter optimization, the optimum sample M50 [Si/Al = 50.2, Si/Sn = 93.8, Si/(Al + Sn) = 43.2] showed the maximum aniline conversion (67\%) and NMA selectivity (81\%) at reaction temperature = 220 degrees C, weight hourly space velocity (WHSV) = 3 h(-1), molar ratio (aniline to methanol) = 1:8 and TOS = 4 h. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Al-Sn-MFI, Aniline, Bronsted and Lewis acid, Methanol, N-methylaniline}, issn = {0926-860X}, doi = {10.1016/j.apcata.2011.05.019}, author = {Niphadkar, P. S. and Joshi, P. N. and Deshpande, Suvarna S. and Bokade, Vijay V.} }