527-84-4Relevant articles and documents
Novel approach towards Al-rich AFI for catalytic application
Zhou, Yong,?ilková, Nadě?da,Shamzhy, Mariya,Avadhut, Yamini,Hartmann, Martin,?ejka, Ji?í,Opanasenko, Maksym
, p. 62 - 68 (2019)
A new germanosilicate structural analogue of AFI zeolite (Ge-AFI) was hydrothermally synthesized. One- and two-step alumination of the Ge-AFI zeolites were used to modify their structure and acidic properties traced using XRD, N2 adsorption, ICP-OES, 27Al NMR, and FTIR spectroscopy. Two-step aluminated sample (deGe-Al-AFI) provided a higher Al content, stronger acid sites and a higher micropore volume than one-step aluminated sample (Al-AFI). Extensive evaluation of the catalytic performance of these AFI zeolites compared with reference conventional zeolite catalysts for alkylation of toluene with isopropyl alcohol showed that deGe-Al-AFI exhibited relatively high toluene conversion and selectivity to valuable p-cymene due to the optimized textural and acidic properties.
Catalytic Property of Calcined Iron Sulfate Treated with Hydrogen Chloride in Alkylation of Toluene and Benzene with Alkyl Chlorides
Arata, Kazushi,Hino, Makoto,Yabe, Katsumasa
, p. 6 - 9 (1980)
Alkylation was carried out at room temperature over catalysts prepared by calcination of FeSO4, Fe2O3, and Fe(OH)3 in the air at various temperatures and subsequent exposure to HCl at room temperature for 20 min.The FeSO4-HCl catalysts heat-treated at 700 and 750 deg C showed very high activity and selectivity, the other catalysts except for the sulfate treated at 800 deg C being almost inactive.The FeSO4(700 deg C)-HCl catalyst was found to consist of FeCl3 and α-Fe2O3 by means of Moessbauer effect, the absorption peak areas being 14 and 86percent for portions of iron based on the chloride and oxide, respectively.The results of DTA and TGA experiments suggest that the coordinate bond of water molecule on FeCl3 of the FeSO4(700 deg C)-HCl catalyst is stronger than that on FeCl3 of the FeSO4 (600, 800, and 900 deg C)-HCl and commercial FeCl3.The FeSO4(700 deg C)-HCl catalyst showed a much higher activity than pure FeCl3.The iron(III) chloride formed by reaction of HCl and α-Fe2O3 obtained by thermal decomposition of the sulfate at 700 or 750 deg C was found to be a very strong Lewis acid catalyst.
The Acidic Property and Catalytic Activity of MoO3-SiO2-Al2O3
Sabu, Kuzhunellil Raghavan Pillai,Rao, Kalur Vijayachandra C.,Nair, Chandrathil Govindan Ramacha.
, p. 1926 - 1932 (1991)
The ternary oxide system MoO3-SiO2-Al2O3 was prepared by coprecipitation method.The pH of coprecipitation has been varied from pH = 2 to pH = 8 and its effect on the acidic properties of the ternary oxide acidic system was studied by butylamine titration.The MoO3-SiO2-Al2O3 prepared from highly acidic solution has low acid strength.The total acid amount of the ternary oxide decreased considerably at higher pH (>6) of coprecipitation.It was found that the total acid amount of MoO3-SiO2-Al2O3 containing 9.7 percent (by weight) of MoO3 and silica to alumina molar ratio 16.6 is very high compared with that of SiO2-Al2O3 of the same silica to alumina molar ratio.The acid strength of SiO2-Al2O3 is reduced by the incorporation of MoO3.Increase in calcination temperature increased the acid strength.The catalytic activity of MoO3-SiO2-Al2O3 was found to be very high for the alkylation of toluene with 2-propanol.The products are found to be o-cymene, p-cymene, and three isomers of diisopropyltoluenes.Reaction temperature >200 deg C, higher liquid hourly space velocity, and higher alcohol content in the feed decreased the total conversion of 2-propanol to isopropyltoluenes.The acidic property and catalytic activity of MoO3-SiO2-Al2O3 are not considerably reduced up to four successive regeneration cycles.
Allen et al.
, p. 42 (1959)
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Simons,Hart
, p. 979 (1947)
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Identification by GC-MS of cymene isomers and 3,7,7-trimethylcyclohepta-1, 3,5-triene in essential oils
Romanenko,Tkachev
, p. 699 - 701 (2006)
Retention indices of cymene isomers published in popular GC-MS atlases were found to be erroneous by analyzing synthetic samples. The following retention indices (RI) were found using a nonpolar phase (diphenyl: dimethylpolysiloxane, 5:95) for four essential-oil components with indistinguishable mass spectra: 3,7,7-trimethylcyclohepta-1,3,5-triene (RI = 970), m-cymene (RI = 1022), p-cymene (RI = 1024), and o-cymene (RI = 1039). The relative distributions of these compounds were evaluated based on the analysis of about 1000 essential oils. Simple methods were given for preparing standard mixtures of isomeric compounds for identification by GC-MS.
Facile fabrication of aluminum-promoted vanadium phosphate: A highly active heterogeneous catalyst for isopropylation of toluene to cymene
Behera, Gobinda Chandra,Parida,Das
, p. 190 - 198 (2012)
Vanadium phosphate is well known as a heterogeneous catalyst in gas phase oxidation reactions. To date, there has been little interest in carrying out liquid-phase reactions with vanadium phosphate as catalyst. Herein, we report the catalytic activity of vanadium phosphate and aluminum-promoted vanadium phosphate toward liquid-phase isopropylation of toluene to cymene. The catalysts were unambiguously characterized by X-ray diffraction, N2 adsorption-desorption, FT-IR technique, UV-vis DRS, and FE-SEM. The total acid sites were estimated by an NH3 TPD analyzer. XPS was used as a powerful tool to know the electronic environment of the catalysts. The optimization of the reaction was carried out by varying temperature from 75 to 150 °C and molar ratio (toluene: isopropanol) from 1:1-1:3. Under optimum reaction conditions, 5 wt.% aluminum-promoted vanadium phosphate showed 90% conversion with 85% selectivity to p-cymene.
Halogen-Bridged Methylnaphthyl Palladium Dimers as Versatile Catalyst Precursors in Coupling Reactions
Doppiu, Angelino,Goo?en, Lukas J.,Hu, Zhiyong,Pirkl, Nico,Sivendran, Nardana
supporting information, p. 25151 - 25160 (2021/10/19)
Halogen-bridged methylnaphthyl (MeNAP) palladium dimers are presented as multipurpose Pd-precursors, ideally suited for catalytic method development and preparative organic synthesis. By simply mixing with phosphine or carbene ligands, they are in situ converted into well-defined monoligated complexes. Their catalytic performance was benchmarked against state-of-the-art systems in challenging Buchwald–Hartwig, Heck, Suzuki and Negishi couplings, and ketone arylations. Their use enabled record-setting activities, beyond those achievable by optimization of the ligand alone. The MeNAP catalysts permit syntheses of tetra-ortho-substituted arenes and bulky anilines in near-quantitative yields at room temperature, allow mono-arylations of small ketones, and enable so far elusive cross-couplings of secondary alkyl boronic acids with aryl chlorides.
Three-dimensional 10-ring zeolites: The activities in toluene alkylation and disproportionation
Kub?, Martin,?ilková, Nadě?da,Zones, Stacey I.,Chen, Cong-Yan,Al-Khattaf, Sulaiman,?ejka, Ji?í
, p. 97 - 106 (2015/10/29)
Three-dimensional 10-ring zeolites TUN, IMF, -SVR, MFI and MEL were investigated as for their acid properties, adsorption of 2,2-dimethylbutane and in toluene disproportionation and its alkylation with isopropyl alcohol. The results were compared against zeolite?SFV, the structure of which consists mainly of MEL zeolite with some additional 12-ring channel system. With exception of -SVR synthesized with high Si/Al ratio, all other zeolites provided Si/Al ratios in a narrow region. Novel zeolites TUN, IMF, and -SVR exhibited higher conversions than MFI and MEL in toluene alkylation. TUN and IMF were substantially more active in toluene disproportionation indicating less diffusion restrictions of channel structure on the disproportionation reaction.?SFV showed a similar catalytic behavior to MEL with much lower selectivity to p-xylene and p-cymene. This could indicate that both toluene disproportionation and alkylation proceed in reaction space of?SFV being similar to those of MFI and MEL.?SFV and TUN exhibited much faster adsorption of 2,2-dimethylbutane than MFI, MEL, IMF, and -SVR. It was concluded that the presence of some larger transport pores in?SFV than in other zeolites is responsible for fast adsorption of 2,2-dimethylbutane and transport of products resulting in a low selectivity to p-xylene and p-cymene.