Hydride hydrogenation

Step 1 Hydride (hydrogen + two electrons) is transferred from boron to the positively polarized carbon of the carbonyl group The carbonyl oxygen bonds to boron... 

Alternatively, A- ylium names may be formed by a special application of the A convention, according to which the affected atom is considered to be formally derived from a hypothetical parent that has a hydridic hydrogen attached in lieu of the positive charge. Such an operation... 

Dimethyl-4-hydroxymethyl-1.3-dioxolane Sodium hydride Hydrogen chloride... 

On the basis of the related experimental evidence and its discussion one can regard the poisoning effect of the hydride hydrogen in nickel and its alloys with copper as normally accompanying the heterogeneous recombination of hydrogen atoms on these catalysts at lower temperatures. 

The spectrum of R has absorption bands in the 1000 cm-1 region that can be attributed to coordinated THF.(7, 8) The broad absorption in the spectrum of P in the 1000-1150 cm"" region is probably due to skeletal and deformation vibrations.(5) The absence of absorption at 1200-1350 cm-1 indicates that there are probably no hydride hydrogens.(8)... 

In an irreversible metal hydride, hydrogen is generated through a chemical reaction, which is not easily reversible onboard a vehicle. Common reactant is water or an alcohol. For example, sodium borohydride can produce hydrogen as... 

Metal hydride hydrogen-fuel-cell-powered system. (Reproduced with permission from Heung, L.K., Using Metal Hydride to Store Hydrogen, U.S. Department of Commerce, National Technical Information Service... 

SOLID-H , Metal Hydride Hydrogen Storage Containers, available at http //www. hydrogencomponents.com, January 2007. 

The starting material is always the chalcogenol and, consequently, is more used for thiols than selenols and tellurols. There are several types of reactions depending if the starting materials are metal hydrides (hydrogen elimination), complexes with M C (alkane elimination), M-N (transamination), or M-O (hydrolysis) bonds. 

Complex metal hydrides, hydrogen storage and, 13 851 Complex salts krypton, 17 333 radon, 17 335 xenon, 17 326-330 Compomers, 8 334-335 Component concentrations, rate law and, 14 609... 

Hydrogen chloride-water-inorganic compound systems, 13 817-818 Hydrogen composite curves, 20 746, 747 Hydrogen compounds. See Hydrides Hydrogen content, determination of, 13 789-790... 

Prins64 has recently discovered that lithium aluminum hydride hydrogenates 1,2-epoxides smoothly in high yield this single-step reaction would appear to outmode the Raney nickel desulfurization process for this purpose. 

Toyota and Honda have been experimenting with both methanol and metal-hydride storage of hydrogen. Honda has built several test cars, in 1999 a Honda FCX-V1 (metal-hydride hydrogen) and FCX-V2 (methanol) were tested at a track in Japan. The Ballard powered version-1 was ready, but proved to be a little sluggish and noisy. The other car suffered from a noisy fuel cell. Both Honda fuel cell test cars were built on the chassis of the discontinued EV Plus battery electric. Honda used a different and more aerodynamic body. 

Toyota has been sharing technology with partner GM on electric, hybrid, and fuel cell cars. In 1998, the research division was testing methanol reformers and metal hydride hydrogen storage and had prototypes of each. 

The phosphoranylidene ylide (5) has been obtained as shown in Scheme 2. When fluoride ion is exchanged by chloride ion and the compound heated to its melting point with sodium hydride, hydrogen is evolved and the bis-ylide (6) is distilled from the reaction mixture.9... 

Improvement in metal hydride hydrogen storage has been slow in achieving the targets needed for several applications. But slow, steady progress is foreseen as material processing in the nano-range improves the kinetics, thermodynamics, and capacity of the metal hydride systems so that they become acceptable for some applications perhaps for stationary systems. 

Andrukaitis, E., and Ali R. Sallehy, Chemical Hydride Hydrogen Generator For Military Applications, Proceedings of the NHA Annual Hydrogen Conference 2004, Los Angeles, California, 26-30 April 2004. 

Metals, intermetallic compounds, and alloys generally react with hydrogen and form mainly solid metal-hydrogen compounds (MH ). Hydrides exist as ionic, polymeric covalent, volatile covalent and metallic hydrides. Hydrogen reacts at elevated temperatrrres with many transition metals and their alloys to form hydrides. Many of the MH show large deviations from ideal stoichiometry (n= 1, 2, 3) and can exist as multiphase systems. 

Scheme 3.28 depicts the proposed reaction mechanism that may happen on these alloys. The first step is the coordination of the ester to the alloy via its oxygen atoms (it is likely that hn favors this coordination due to its electrophilicity). In a second step there is a four-center mechanism where the hydridic hydrogen makes a nucleophilic attack at the electrophilic carbon atom of the carbonyl with forma-... 

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