Absorption of hydrogen

Absorption of Hydrogen Chloride. Effective heat stabilizers have the abiHty to bind hydrogen chloride. Most stabilizer systems contain one or more metallic soaps or salts which readily undergo a simple acid—base reaction with the by-product hydrogen chloride as the PVC degrades ... 

Hydrides. Zirconium hydride [7704-99-6] in powder form was produced by the reduction of zirconium oxide with calcium hydride in a bomb reactor. However, the workup was hazardous and many fires and explosions occurred when the calcium oxide was dissolved with hydrochloric acid to recover the hydride powder. With the ready availabiHty of zirconium metal via the KroU process, zirconium hydride can be obtained by exothermic absorption of hydrogen by pure zirconium, usually highly porous sponge. The heat of formation is 167.4 J / mol (40 kcal/mol) hydrogen absorbed. 

Barium hydro sulfide [25417-81-6], Ba(HS)2, is formed by absorption of hydrogen sulfide into barium sulfide solution. On addition of alcohol, barium hydrosulfide tetrahydrate [12230-74-9], Ba(HS)2 4H2O, crystallizes as yellow rhombic crystals that decompose at 50 °C. Sohd barium hydro sulfide is very unstable. Its solubility in water is... 

A solution of 10 g of 9 10-dihydro-9 10-ethano-(1 2)-anthracene-(9)aldehyde (made from anthracene and acrolein) and 10 g of monomethylamine in 100 cc of ethanol is heated at 80°C for 4 hours in an autoclave. The reaction mixture is then evaporated to dryness under reduced pressure to leave a crystalline residue which is dissolved in 150 cc of ethanol and, after the addition of 2 g of Raney nickel, hydrogenated at 40°C under atmospheric pressure. When the absorption of hydrogen has subsided, the catalyst is filtered off and the filtrate evaporated under reduced pressure. An oil remains which is covered with 100 cc of 2N hydrochloric acid. The 9-methylamino-methyI-9 10-dihydro-9 10-ethano-(9 10)-anthracene hydrochloride crystallizes immediately after crystallization from methanol it melts at 320°-322°C. 

A solution containing 26.3 mg of vitamin 6,2 in 15 ml of water was shaken with 78 mg of platinum oxide catalyst and hydrogen gas under substantially atmospheric pressure at 25 C for 20 hours. Hydrogen was absorbed. During the absorption of hydrogen the color of the solution changed from red to brown. The solution was separated from the catalyst and evaporated to dryness in vacuo. The residue was then dissolved in 1 ml of water and then diluted with about 6 ml of acetone. 

To the aqueous suspension of the palladized charcoal catalyst thus obtained are added 20.8 kg of 3-cyano-pyridine (96% purity) and then are added 70 liters of a hydrochloric acid solution prepared by diluting 30 liters of 36% HCI with 40 liters of water. This represents approximately 1.75 mols of HCI for each mol of 3-cyano-pyridine. The suspension is maintained at 10° to 15°C and stirred continuously while introducing a current of hydrogen at a pressure of 3 to 5 psi. When absorption of hydrogen ceases and the 3-cyano-pyridine is completely reduced, the reaction mixture is filtered to remove the catalyst. 

Absorption of hydrogen chloride in weak hydrochloric acid... 

The inhibitor should not decompose during the life of the pickle nor decrease the rate of scale removal appreciably. Some highly efficient inhibitors, however, do reduce pickling speed a little. It would be expected that since the hydrogen evolution is reduced the amount of hydrogen absorption and embrittlement would also be reduced. This is not always the case thiocyanate inhibitors, for example, actually increase the absorption of hydrogen. 

A convenient trap (Fig. 3) devised by John R. Johnson for the absorption of hydrogen chloride, or for the elimination of sulfur dioxide, hydrogen cyanide, etc., may be arranged as shown in the figure. The gases are led into a chamber in which a stream of water (from the reflux condenser in this case) flows downward into a large bottle. The bottle is provided with a... 

Switendick was the first to apply modem electronic band theory to metal hydrides [5]. He compared the measured density of electronic states with theoretical results derived from energy band calculations in binary and pseudo-binary systems. Recently, the band structures of intermetallic hydrides including LaNi5Ht and FeTiH v have been summarized in a review article by Gupta and Schlapbach [6], All exhibit certain common features upon the absorption of hydrogen and formation of a distinct hydride phase. They are ... 

In addition to the surface physics and chemistry phenomena involved, a further effect may follow the interaction at the hydrogen-metal surface, that is the absorption of hydrogen by the bulk phase of the metal. This absorption leads to the formation of a solid solution within a certain, usually low, range of hydrogen concentrations. However, with several transition metals, exceeding a certain limit of hydrogen concentration results in the formation of a specific crystallographically distinct phase of the... 

Hare W. F. J., Welsh H. L. Pressure induced infrared absorption of hydrogen and hydrogen-foreign gas mixtures in the range 1500-5000 atmospheres, Can. J. Phys. 36, 88-103 (1958). 

In their electrochemical surface properties, a number of metals (lead, tin, cadmium, and others) resemble mercury, whereas other metals of the platinum group resemble platinum itself. Within each of these groups, trends in the behavior observed coincide qualitatively, sometimes even semiquantitatively. Some of the differences between mercury and other. y- or p-metals are due to their solid state. Among the platinum group metals, palladium is exceptional, since strong bulk absorption of hydrogen is observed here in addition to surface adsorption, an effect that makes it difficult to study the surface itself. 

Tateishi N, Yahikozawa K, Nishimura K, Masato S, Iwanaga Y, Watanahe M, Enami E, Matsuda Y, Takasu Y. 1991. Electrochemical properties of ultra-fine palladium particles for adsorption and absorption of hydrogen in an aqueous HCIO4 solution. Electrochim Acta 36 1235-1240. 

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