- Silica-immobilized ionic liquid Br?nsted acids as highly effective heterogeneous catalysts for the isomerization of: N -heptane and n -octane
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Metal-free imidazolium-based ionic liquid (IL) Br?nsted acids 1-methyl imidazolium hydrogen sulphate [HMIM]HSO4 and 1-methyl benzimidazolium hydrogen sulphate [HMBIM]HSO4 were synthesized. Their physicochemical properties were investigated using spectroscopic and thermal techniques, including UV-Vis, FT-IR, 1H NMR, 13C-NMR, mass spectrometry, and TGA. The ILs were immobilized on mesoporous silica gel and characterized by FT-IR spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis, ammonia temperature-programmed desorption, and thermogravimetric analysis. [HMIM]HSO4?silica and [HMBIM]HSO4?silica have been successfully applied as promising replacements for conventional catalysts for alkane isomerization reactions at room temperature. Isomerization of n-heptane and n-octane was achieved with both catalysts. In addition to promoting the isomerization of n-heptane and n-octane (a quintessential reaction for petroleum refineries), these immobilized catalysts are non-hazardous and save energy.
- Al-Fatesh, Ahmed S.,Dhar, Abhishek,Fakeeha, Anis H.,Ibrahim, Ahmed A.,Khimani, Mehul,Patel, Hiren,Siva Kumar, Nadavala,Vekariya, Rohit L.
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p. 15282 - 15292
(2020/05/05)
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- Dual Rh?Ru Catalysts for Reductive Hydroformylation of Olefins to Alcohols
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An active and selective dual catalytic system to promote domino hydroformylation–reduction reactions is described. Apart from terminal, di- and trisubstituted olefins, for the first time the less active internal C?C double bond of tetrasubstituted alkenes can also be utilized. As an example, 2,3-dimethylbut-2-ene is converted into the corresponding n-alcohol with high yield (90 %) as well as regio- and chemoselectivity (>97 %). Key for this development is the use of a combination of Rh complexes with bulky monophosphite ligands and the Ru-based Shvo's complex. A variety of aromatic and aliphatic alkenes can be directly used to obtain mainly linear alcohols.
- Rodrigues, Fábio M. S.,Kucmierczyk, Peter K.,Pineiro, Marta,Jackstell, Ralf,Franke, Robert,Pereira, Mariette M.,Beller, Matthias
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p. 2310 - 2314
(2018/07/31)
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- Compositions and methods for the treatment of multiple sclerosis
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The present invention relates to compounds of Formula I and Formula II or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of Formula I and Formula II; and formulated to treat an underlying etiology by oral administration, delayed release or sustained release, transmucosal, syrup, topical, parenteral administration, injection, subdermal, oral solution, rectal administration, buccal administration or transdermal administration.
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- Compositions and methods for the treatment of moderate to severe pain
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The invention relates to the compounds of formula I or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I; and methods for treating or preventing moderate to severe pain, may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, syrup, or injection. Such compositions may be used to treatment of muscle pain, spasticity, neuropathic pain, fibromyalgia, post-operative pain, muscle spasticity, headache, chronic pain, sub-chronic pain and local pain.
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- Hydroisomerization of n-octane on molybdenum based catalyst
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Balanced metal-acid bifunctional MoO2-x(OH)y catalytic system has been prepared. 2-3 monolayers of this phase on the sample surface were obtained following controlled reduction by hydrogen of equivalent 5 monolayers of MoO3/sub
- Al-Kandari,Al-Kharafi,Katrib
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scheme or table
p. 141 - 148
(2010/11/03)
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- Effect of zeolite structure and acidity on the product selectivity and reaction mechanism for n-octane hydroisomerization and hydrocracking
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The activity, product selectivity, and stability of a series of bifunctional zeolite catalysts, primary ZSM-12, USY, and β-zeolite, with different Si/Al ratios were compared for the hydroisomerization and hydrocracking of n-octane. The performance of L-zeolite and mordenite was examined to a lesser extent as well. It was found that the activity per acidic site decreases at the initial stage (1 h on stream) in the following order: ZSM-12 > β-zeolite > mordenite > USY > L-zeolite. For extended periods of operation, the activity of ZSM-12 remains unchanged. The superior stability of ZSM-12 even under accelerating coking conditions results from its unique pore structure, which does not favor coke formation. Its one-dimensional noninterpenetrating puckered channels (5.5 × 6.1 A) act as perfect tubes, which do not trap coke precursors. The branched product selectivity increases with the increase in Bronsted acid site strength of the zeolite catalysts, and thus hydroisomerization is favored at the expense of cracking at a higher Bronsted acid strength. USY-5.8 (CBV-712) showed relatively high initial activity with respect to other USYs. This is probably related to its high surface Al content. The Bronsted acid strength of the USY zeolites decreases in the order USY-2.6 > USY-28 > USY-5.8. The 2,2-DMC6 and 3,3-DMC6 isomers are not favored as final products due to their bulky molecular size even in USY. In addition, the 2,2-DMC6 species is more abundant than 3,3-DMC6 because the rate of isomerization by PCP intermediates decreases in the following order: 2-MC7 > 3-MC7 > 4-MC7. The 2,3-DMC6 concentration is much higher than that predicted by equilibrium, which indicates that the interconversion of 2,3-DMC6 to other dibranched isomers is not preferred. The i-C4/n-C4 ratio detected depends on both the reaction temperature and zeolite pore structure/acidity. Aluminium content determines the type of β-scission. For zeolites with a high concentration of acid sites (Si/Ai about 30), type A β-scission dominates at low temperature, while at lower Al content, type A, B, and C β-scissions are equally important.
- Zhang, Wenmin,Smirniotis, Panagiotis G.
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p. 400 - 416
(2007/10/03)
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- ALKANE DEHYDROCYCLIZATION AND ALKYLCYCLOPENTANE CONVERSIONS AT 13.8 bar (200 psi) WITH Pt-Al2O3 CATALYSTS
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The selectivity, defined as aromatics/isoalkanes, for the formation of aromatics is greater for the conversion of n-alkanes than for the conversion of alkylcyclopentanes with a platinum nonacidic alumina catalyst.Alkylcyclopentanes undergo hydrogenolysis to isoalkanes with the same carbon number at least ten to twenty times faster than they react to form aromatics over this catalyst.The results do not support an aromatization mechanism that includes the formation of five carbon ring intermediates.
- Hardy, Rita H.,Davis, Burtron H.
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p. 269 - 278
(2007/10/02)
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- HOMOLOGATION OF HEXANE ISOMERS CATALYZED BY PLATINUM
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The homologation of n-hexane, 3-methylpentane, hexadienes and n-heptane were studied over Pt-black (and some supported Pt) and compared to the reactions of C8 hydrocarbons.The composition of C8-aromatics was used to evaluate the possible pathways.The ratio of internal to terminal addition was about 0.25; this way, the C8-composition from n-hexane could be explained.The appearence of branched chain saturated buildup products from 3-methylpentane and methylcyclopentane complicates their homologation and confirms the possibility of addition of C1 units to internal C-atoms, too.The mechanism of O'Donohoe et al. was found to be valid.
- Dobrovolszky, Maria A.,Paal, Zoltan,Tetenyi, Pal
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