Hydrogen storage by reversible hydrogenation of pi-conjugated substrates

A process for releasing hydrogen comprising:

• exposing a liquid comprising at least one at least partially hydrogenated pi-conjugated compound with an effective amount of at least one catalyst under conditions sufficient to remove hydrogen from the liquid thereby producing a hydrogen containing fluid;
• wherein:
• i) the compound comprises at least one conformer comprising at least one member selected from the group consisting of extended pi-conjugated substrates with a heteroatom, extended pi-conjugated substrates with greater than three rings and extended pi-conjugated substrates with at least two rings wherein one ring is a five membered ring, ii) the process is substantially free of solvents, and iii) hydrogen can be reintroduced and subsequently removed from the compound.

A repeatable dehydrogenation process comprising:

• introducing a liquid comprising at least one conformer of at least partially hydrogenated pi-conjugated compound into an environment containing at least one catalyst under conditions that are sufficient to dehydrogenate at least a portion of said compound wherein said compound:
• i) comprises at least one member selected from the group consisting of extended pi-conjugated substrates with a heteroatom, extended pi-conjugated substrates with greater than three rings and extended pi-conjugated substrates with at least two rings wherein one ring is a five membered ring, and ii) can be repeatedly hydrogenated and dehydrogenated.

A method for producing hydrogen gas comprising:

• a) heating a liquid comprising at least one, at least partially hydrogenated pi-conjugated substrate having at least one heteroatom and at least one conformer of the substrate, and at least one catalyst thereby producing hydrogen gas and at least one liquid de-hydrogenated substrate,
• b) separating hydrogen gas from the at least one liquid de-hydrogenated substrate wherein the de-hydrogenated substrate is less volatile than hydrogen and can be hydrogenated, and;
• c) recovering hydrogen gas.

A process for releasing hydrogen comprising:

• exposing a liquid comprising at least one non-equilibrium conformer, of at least one, at least partially hydrogenated compound with an effective amount of at least one catalyst under conditions sufficient to remove hydrogen from the liquid thereby producing a hydrogen containing fluid;
• wherein the conformer comprises at least one member selected from the group consisting of extended pi-conjugated substrates with a heteroatom, extended pi-conjugated substrates with greater than three rings, and extended pi-conjugated substrates with at least two rings wherein one ring is a five membered ring.

The process of 16 wherein the catalyst comprises at least one member selected from the group consisting platinum/rhenium on alumina and platinum/iridium on alumina.

A process for storing hydrogen comprising:

• exposing a liquid comprising at least one non-equilibrium conformer with an effective amount of at least one catalyst under conditions sufficient to hydrogenate a least a portion of the liquid;
• wherein the conformer comprises at least one member selected from the group consisting of extended pi-conjugated substrates with a heteroatom, extended pi-conjugated substrates with greater than three rings, and extended pi-conjugated substrates with at least two rings wherein one ring is a five membered ring.