01722nas a2200229   4500008004100000022001400041245014100055210006900196260007300265300001200338490000800350520085900358653001601217653001101233653001301244653001401257653002101271100002601292700002101318700002801339856012501367       2007                        eng d  a1387-181100aEffect of pretreatment conditions on the catalytic activity of nano-sized TPA/ZrO2 dispersed in SBA-15 channels in acetylation reactions0 aEffect of pretreatment conditions on the catalytic activity of n  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a223-2330 v1023 a<p>Acetylation of an aromatic compounds such as veratrole (1,2-dimethoxybenzene), anisole, thioanisole, isobutyl benzene and 2-methoxynaphthalene with acetic anhydride has been investigated over a nano-sized 12-tungstophosphoric acid (TPA)/22.4 wt.%ZrO2/SBA- 15 catalysts in the liquid phase conditions. Catalysts with different (%) TPA and zirconia loadings calcined at different temperatures were prepared by wet-impregnation and characterized by XRD, N-2 adsorption-desorption, FT-Rarnan, X-ray photoelectron spectroscopy (XPS). The acidic behavior of the catalyst was studied by TPD of ammonia and FT-IR pyridine adsorption. Among the catalysts, 15 wt.%TPA/22.4 wt.%ZrO2/SBA- 15 calcined at 1123 K had the highest acidity and was the most active catalyst in veratrole acetylation with acetic anhydride. (C) 2007 Elsevier Inc. All rights reserved.</p>10aacetylation10aSBA-1510aTPA/ZrO210averatrole10awet-impregnation1 aSawant, Dhanashri, P.1 aHartmann, Martin1 aHalligudi, Shivaraj, B.  uhttps://library.ncl.res.in/content/effect-pretreatment-conditions-catalytic-activity-nano-sized-tpazro2-dispersed-sba-1502438nas 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<p>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.</p>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-veratrole