Solid add catalyst

These experiments demonstrate that the surface-catalyzed 2 reaction is far more effident than either the or C pathway for the dehydrative coupling of alcohols over the solid add catalysts tested. High selectivity to configurationally inverted chiral ethers ensues, espedally in the case of the HZSM-5 catalyst, in which the minor C or C paths were further suppressed by "bottling" of 3-ethoxypentane by the narrow zeolite chaimels. 

Conclusive evidence has been presented that surface-catalyzed coupling of alcohols to ethers proceeds predominantly the S 2 pathway, in which product composition, oxygen retention, and chiral inversion is controlled 1 "competitive double parkir of reactant alcohols or by transition state shape selectivity. These two features afforded by the use of solid add catalysts result in selectivities that are superior to solution reactions. High resolution XPS data demonstrate that Brpnsted add centers activate the alcohols for ether synthesis over sulfonic add resins, and the reaction conditions in zeolites indicate that Brpnsted adds are active centers therein, too. Two different shape-selectivity effects on the alcohol coupling pathway were observed herein transition-state constraint in HZSM-5 and reactant approach constraint in H-mordenite. None of these effects is a molecular sieving of the reactant molecules in the main zeolite channels, as both methanol and isobutanol have dimensions smaller than the main channel diameters in ZSM-S and mordenite. 

K. P. (2001) Deactivation of solid add catalysts for butene skeletal isomerization on the benefldal and harmful effects of carbonaceous deposits. Appl. Catal A, 212, 97-115. 

Solid superacids may be made by treating ordinary solid add catalysts with strong Br0nsted or Lewis acids. For example, if freshly precipitated titanium hydroxide or zirconium hydroxide is treated with sulfuric acid and calcined in air at 500 °C. a very active solid acid catalyst results. The solids consist mainly of the metal dioxides with sulfate ions coordinated to the metal ions on the surface. Likewise, a superacid solid catalyst can be made by treating these metal oxides with antimony penlafluonde. Both catalysts contain both Br nsted and Lewis acid sites, and they arc sufficiently active to catalyze the isomerization of n-butane at room temperature.26... 

Kiss, A.A., Dimian, A.C. and Rofhenberg, G. (2006) Solid add catalysts for biodiesel production — towards sustainable energy. Adv. Synth. Catal., 348, 75. 

Kiss, A. A., Dimian, A.C., Rothenberg, G., Solid add catalysts for biodiesel production-towards sustainable energy, Adv. Synth. Catal., 348, 75-81, 2006 Wang, S-J., Wong, S. H., Design and control of entrainer-aided reactive distillation for fatty ester production, Ind. Eng. Chem. Res., 45, 9041-9049, 2006... 

D Amico, V.J. et al. (2002) The AlkyClean process a new solid add catalyst gasoline alkylation technology. 

The direct reaction of Brdnsted acids with support materials has also been used to prepare solid add catalysts. Simple treatment of silica gel with sulfuric add followed by mild drying gives a solid acid that is active in various aromatic nitrations (nitric add or isopropyl nitrate as nitrating agent).128 Activity of the solid acid is comparable to the more expensive Nafion-H. 

Other Solid-add Catalysts - Chromium on an aluminophosphate support, which is supposed to be a polymerization catalyst, was used in the oligomerization of light olefins and ethylene. For ethylene oligomerization, the catalyst exhibited activity for dimerization, with around 60% conversion to C4 fractions. In another patent the support and the active phase were the same as in the previous patent, except that the support had been treated with a solution of triethylaluminium in toluene before being contacted with the chromium compound. The catalyst system showed selectivity towards trimerization. When... 

Metal Oxide Nanotube Solid Acid A one-dimensional metal oxide, titanium nanotube was reported as a solid add catalyst [56]. Protonated titanium nanotubes were synthesized by the hydrothermal treatment of bulk titanium oxide in high pH solution, followed by proton exchange. The nanotubes have high surface... 

Isao T, Masahiro S, Megumu I, Kazuhisa M (2005) Dehydration of ethanol into ethylene over solid add catalysts. Catal Lett 105 3 ... 

Mo and P sources, respectively [59]. This gives rise to a supported acidic species that can act as solid add catalyst, much more environmentally friendly than... 

De La Hoz, A., Moreno, A., Vazquez, E. (1999). Use of microwave irradiation and solid add catalysts in an enhanced and environmentally friendly synthesis of coumarin derivatives. Synlett, 608—610. 

Song X, Sayari A Sulfated zirconia-based strong solid-add catalysts recent progress. Catal Rev-Sci Eng 1996, 38 329-412. 

Srilatha, K., C. Ramesh Kumar, B. L. A. Prabhavathi Devi, R. B. N. Prasad, P. S. Sai Prasad N. Lingaiah (2011) Efficient solid add catalysts for esterification of free fatty adds with methanol for the production of biodiesel. Catalysis Science Technology, 1, 662,1SSN 2044-4753 2044-4761. 

Synthesis of smectite-type clay minerals, such as saponites, may ciieumvcnt the above mentioned difficulties. The usually demanding hydiolfaermal treatment [3>4, the lo duration of the synthesis [5], and problems with the scale-up of the jxq>aratk procecterc. however, have thus far severely limited die use of synthetic clays as solid add catalysts. 

M. Selvaraj, B.R. Min, Y.G. Shul, T.G. Lee, Comparison of mesoporous solid acid catalysts in the production of DABCO by cyclization of ethanolamine. Part 1 s)fnthesis and characterization of mesoporous solid add catalysts, Microporous Mesoporous Mater. 74 (2004) 157-162. 

Shu, Q., et al., 2010. Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid add catalyst. Applied Energy 87 (8), 2589—25%. Available at http //www.scienceditect.eom/science/article/pii/S0306261910000887 (accessed 26.05.14.). 

The dimerization of isobutene carried out in a forced-flow polymeric catalytic membrane reactor was reported by D. Fritsch and co-workers. The authors prepared composite porous membranes consisting of a catalytic layer made of solid add catalysts, such as siUca supported Naflon , Nafion NR50, Amberlyst 15 and silica supported tungstophosphoric add dispersed in polymeric binders such as Teflon AF, Hyflon AD, polytrim-ethylsilylpropyne, or polydimethylsiloxane (PDMS), cast on microporous support membranes made of polyacrylonitrile (PAN) or Torlon . The membranes were assembled in the membrane reactor into which isobutene was fed in the retentate side with a build-up pressure of 4 bar. The liquid product was collected on the permeate side. 

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