Hydrogen supported

For more selective hydrogenations, supported 5—10 wt % palladium on activated carbon is preferred for reductions in which ring hydrogenation is not wanted. Mild conditions, a neutral solvent, and a stoichiometric amount of hydrogen are used to avoid ring hydrogenation. There are also appHcations for 35—40 wt % cobalt on kieselguhr, copper chromite (nonpromoted or promoted with barium), 5—10 wt % platinum on activated carbon, platinum (IV) oxide (Adams catalyst), and rhenium heptasulfide. Alcohol yields can sometimes be increased by the use of nonpolar (nonacidic) solvents and small amounts of bases, such as tertiary amines, which act as catalyst inhibitors. 

The close correspondence between the properties of Mu in Si as determined by /u,SR and pLCR and those for the AA9 center produced by implanting hydrogen in silicon shows that Mu in silicon and the AA9 center are isostructural and in fact almost identical. They are neutral isolated bond-centered interstitials. Numerous theoretical studies support this conclusion. The observation of such similar centers for muonium and hydrogen supports the generalization that hydrogen analogs of many of the muonium centers exist. Of course, this assumes that the effects of the larger zero-point vibration of the muon relative to the proton do not make a major contribution to structural differences. The p-SR experiments, reinforced by theory, demonstrate that another structure also exists for muonium in silicon, called normal muonium or Mu. This structure is metastable and almost certainly is isolated neutral muonium at a tetrahedral interstitial site. 

The isolation of 2,2 -dihydroxy-3,3 -dimethoxy-5,5 -dialkylbiphenyls from both neutral (IS) and alkaline hydrogenation supports Pew s proposal that the biphenyl structure is of considerable importance in lignin... 

Our works were performed partially under managements of RITE as a part of Environmentally-Friendly Technology for the Production of Hydrogen supported by New Energy and Industrial Technology Development Organization (NEDO). 

Nickel is used for high-pressure hydrogenations. Supported-Ni catalysts such as Raney-Ni and Ni-Boride are employed for hydrogenolysis of the C-S bonds in... 

The electrolysis products of different carboxylates have been compared with the ionization potentials of the intermediate radicals. From this it appeared that alkyl radicals with gas-phase ionization potentials smaller than 8 eV mainly lead to carbenium ions. Accordingly, a-substituents such as carboxy, cyano or hydrogen support the radical pathway, whilst alkyl, cycloalkyl, chloro, bromo, amino, alkoxy, hydroxy, acyloxy or aryl more or less favor the route to carbenium ions. Besides electronic effects, the oxidation seems also to be influenced by steric factors. Bulky substituents diminish the extent of coupling. The main experimental factors that affect the yield in the Kolbe electrolysis are the current density, the pH of the electrolyte, ionic additives, the solvent and the anode material. 

Despite the inclement weather and measly media attention, to solar hydrogen supporters the Xerox-CAN project was an auspicious beginning. The ebulliently expansive Staples (who has since then left the project) said Hopefully, history will look back at the 1990s as the decade when all this began. I just hope we can claim a footnote in that effort. This project is the first step in implementing the vision of many of you that are here today. ... 

Some hydrogen supporters feel that, in view of the complexity of rocket technology, NASA s experience may not be very relevant to the everyday safety problems likely to be posed by a future civilian hydrogen economy. Still, it is noteworthy that NASA has used and handled stupendous amounts of LH2, most of it hauled by barge and tanker-trailer over hundreds of miles to Cape Canaveral and other sites. 

Key words Benzene hydrogenation, supported nickel, optimum concentration, nickel area, dispersion, nickel crystallite. 

Thrust a lighted splinter up into an inverted bottle of hydrogen. Slowly withdraw the splinter so that it will relight at the mouth of the bottle. Look for a deposit on the inside of the bottle and feel of the neck of the bottle. (10) What took place in the bottle (11) What was the evidence (12) Why did no loud explosion, like those in the preceding experiments, occur (13) What is formed when hydrogen burns in the air (14) Does hydrogen support combustion (15) What was the evidence ... 

As is customary with frequency response, the terms are described by the ratio of the output to the input of a real system. The raw data from a frequency scan as the hydrogen-supported nickel system, are illustrated in Fig. 7a (9 versus log w) and 7b (B versus log co). Figure 8 shows... 

One of the systems considered on which reliable data were available was No. 3 (Table I), the hydrogen-supported nickel system. Nickel is known to be highly adsorbing but certainly is not the only adsorbent of this type. 

The same calculation as the above can be made for the hydrogen-supported nickel system when the total system pressure is 0.1 atm... 

Having selected the hydrogen-supported nickel system as being particularly suited for investigation we should still determine whether we can study with our apparatus the range of frequencies in which adsorption phenomena are likely to occur and be measurable. 

The hydrogen-supported nickel system has been reported by Schuit and de Boer 48) as having both fast and slow adsorptions occurring. In addition precise data are available 45) on the isothermal variation of pressure with adsorption time on a similar hydrogen-supported nickel system. This classical adsorption data (step response data) can be mathematically transformed to simulate frequency response data by means of suitable mathematical techniques before any experimentation on the system is begun. The results of this simulation will be much the same as though an actual frequency response of Doerner s hydrogen-supported nickel system had been made. Actually any published adsorption isotherm data can be treated. However, the limitations of the simulation method are threefold (1) very accurate adsorption versus time data are required (2) the accuracy and dependability of the result at very fast times are subject to question (3) the adsorptions are not reproducible in the sense that only one real experiment was made for all adsorptions and the sensitivity of the mathematics could distort the result. 

The evidence for several types of adsorption (four types plus an ultra-slow exponential due perhaps to internal oxygen diffusion) was sufficiently strong to justify study of the hydrogen-supported nickel system by actual frequency response measurement. 

By regulating the temperature and partial pressure of hydrogen, supported nickel catalysts can be used in controlling demethylation reactions. 

When the support contains cations that are not easily reducible (i.e. those of Al, Si, Mg, Zr), hydrogen spillover occurs above 573 K without observable chemical reaction (Class A). However if it contains ferric ions as impurities, as is often the case with alumina, reduction to ferrous ion is detectable by EPR and if it contains sulfate ion, as may be the case with titania, reduction of the precursor with hydrogen automatically generates hydrogen sulfide which poisons the metal (Class B). If deuterium is used in place of hydrogen, support hydroxyls... 

However, for the hydrocarbons, heats of hydrogenation support Hiickers + 2 rule for aromatic character, although the resonance energies, in some cases, are considerably reduced by the energy of charge separation. 

The presence of n-butyl end groups in polymer chains formed during propene polymerization in the presence of hydrogen supports this hypothesis [85, 91-93]. The possibility of formation of the inactive centers Mt-CH(CH3>2 by the reaction of chain transfer with the monomer in a secondary 2,1-orientation or by a secondary insertion in the Mt-H bond, formed as a result of chain transfer to hydrogen, has been considered [76] ... 

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