| abstract |
Processes are provided for the storage and release of hydrogen by means of a substantially reversible catalytic hydrogenation of extended pi-conjugated. The hydrogen, contained in the at least partially hydrogenated form of the extended pi-conjugated system, can be facilely released for use by a catalytic dehydrogenation of the latter in the presence of a dehydrogenation catalyst which can be effected by lowering the hydrogen gas pressure, generally to pressures greater than 0.1 bar or raising the temperature to less than 250 DEG C or less, or by a combination of these two process parameters. Also disclosed is a dispenser useful for dispensing a first liquid and retrieving a second liquid comprising a first conduit having an orifice for dispensing the first liquid, and a second conduit having an orifice for retrieving a second liquid in direction countercurrent to the first liquid, and methods of use thereof. In one embodiment, the invention also relates to the use of the dispenser in a fueling process. |