Hydrogen-silica reactions

Crowley MS. Hydrogen silica reactions in refractories. Am Ceram Soc Bull 1967 46 679-682. 

Crowley MS. Hydrogen Silica Reactions in Refractories, Part II. Am Ceram Soc Bull 1970 49 527-530. 

This reaction is cataly2ed by silica, bauxite, and various metal sulfides. The usual catalyst is activated alumina, which also cataly2es the reduction by methane (228). Molybdenum compounds on alumina are especially effective catalysts for the hydrogen sulfide reaction (229). 

The existence of two different rhodium species co-existing on the silica support can be used as an advantage by controlling their relative amount. Under standard hydroformylation conditions, the cationic species and the neutral hydride complex are both present in significant amounts. Hence hydroformylation and hydrogenation will both proceed under a CO/H2 atmosphere. Indeed a clean one-pot reaction of 1-octene to 1-nonanol was performed, using the supported catalyst for a hydroformylation-hydrogenation cascade reaction. 98 % of the 1-octene was converted in the... 

It is generally accepted that aluminum deficient structures derived from type Y zeolite alter the extent of hydrogen transfer reactions which ordinarily favor the formation of paraffins and aromatics at the expense of olefins and naphthenes. This octane reducing reaction is controlled principally by the silica/alumina ratio of the zeolite and its rare earth content(1). 

The focus of these studies has been on identifying mild activation conditions to prevent nanoparticle agglomeration. Infrared spectroscopy indicated that titania plays an active role in dendrimer adsorption and decomposition in contrast, adsorption of DENs on silica is dominated by metal-support interactions. Relatively mild (150° C) activation conditions were identified and optimized for Pt and Au catalysts. Comparable conditions yield clean nanoparticles that are active CO oxidation catalysts. Supported Pt catalysts are also active in toluene hydrogenation test reactions. 

Upon UV irradiation in hydrocarbon solution, the hexacarbonyls of chromium, molybdenum, and tungsten react differently with conjugated dienes like 1,3-butadiene (la), ( )-l,3-pentadiene (lb), 2-methyl-1,3-butadiene (lc), ( , )-2,4-hexadiene (Id), ( )-2-methyl-l,3-pentadiene (le), 2-ethyl-1,3-butadiene (If), or 1,3-cyclohexadiene (Ig). Chromium hexacarbonyl (2) yields, with the acyclic dienes la-lf, tetracarbonyl-r/2-dienechromium(0) complexes (3a-3f) in a smooth reaction (8-10). With 1,3-cyclohexadiene, in addition to 3g, dicarbonylbis(>/4-l,3-cyclohexadiene)chromium(0) (4g) is obtained [Eqs. (7) and (8)j. During chromatography on silica gel, the 1,3-cyclohexadiene complex 3g dismutates readily to [Cr(CO)6] and 4g [Eq. (9)]. Under the same conditions with 2 1,3-cyclopentadiene (lh) yields, in a hydrogen-transfer reaction, the stable dicarbonyl- / 5-cyclopentadienyl-r/ 3-cyclopent-enylchromium (5) (11-13) [Eq. (10)]. 

The fluorination of hydrogen-methane mixtures in both inconel and fused silica reaction vessels has been studied by Mercer and Pritchard They noted rather severe complications from surface interactions but were able to evaluate the rate coefficient ratio k jk = 2.4 0.2 for... 

All manipulations were carried out in Kel-F, Teflon FEP, or fused silica reaction vessels attached to a stainless steel or Monel fluorine-type vacuum system and/or in a Vacuum Atmospheres inert atmosphere Dri lab. Hexafluorobenzme, oclafluorotoluene, octafluoronaphthalene (PCR Inc., Gainesville, FL), sulfur dioxide, anhydrous hydrogen fluoride (Matheson, E. Rutherford, NJ), cesium fluoride (ROC/RIC, Sun Valley, CA), trifluoroacetic acid (Aldrich, Milwaukee, Wl), and tungsten hexafluoride, arsenic pentafluoride, and antimony pentafluoride (Ozark-Mahoning, Inc., Tulsa, OK) were used as received after their purity was checked by infrared spectroscopy. Dioxygenyl salts and rhenium and... 

A mixture of formalin and ethanol was passed at 240—320 C over various metal oxides supported on silica gel and metal phosphates. The main products were acrolein, acetaldehyde, methanol, and carbon dioxide. Acidic catalysts such as V-P oxides promoted the dehydration of ethanol to ethene. The best catalytic performances for acrolein formation are obtained with nickel phosphate and silica-supported tungsten, zinc, nickel, and magnesium oxides. With a catalyst with a P/Ni atomic ratio of 2/3, the yields of acrolein reach 52 and 65 mol% on ethanol basis with HCHO/ethanol molar ratios of 2 and 3, respectively. Acetaldehyde and methanol are formed by a hydrogen transfer reaction from ethanol to formaldehyde. Then acrolein is formed by an aldol condensation of formaldehyde with the produced acetaldehyde [40],... 

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