Process for the production of hydrogen

Abstract

The present invention relates to a process for the production of hydrogen comprising contacting at least one complex of formula (I), wherein: X- is an anion; Y is N or CR6; M is selected from Ru, Os and Fe; each of A and B is independently a saturated, unsaturated or partially unsaturated carbocyclic ring; R5, R6 and R7 are each independently selected from H, NR24R25, C1-6-alkyl and C1-6- haloalkyl, or two or more of R5, R6 and R7 are linked, together with the carbons to which they are attached, to form a saturated or unsaturated carbocyclic group; R8-R25 are each independently selected from H, C1-6-alkyl, C1-6-haloalkyl and a linker group optionally attached to a solid support; with at least one substrate of formula (II), R1R2-NH-BH-R3R4 (II), wherein R1, R2, R3 and R4 are each independently selected from H, C1-20-alkyl, fluoro- substituted-C1-20-alkyl and C6-14-aryl, or any two of R1, R2, R3 and R4 are linked to form a C2-10-alkylene group, which together with the nitrogen and / or boron atoms to which they are attached, forms a cyclic group. Further aspects of the invention relate to a hydrogen generation system comprising a complex of formula (I), a substrate of formula (II) and a solvent, and to the use of complexes of formula (I) in fuel cells. Another aspect of the invention relates to novel complexes of formula (I).

Description

technical field [0001] The present invention relates to the preparation of H 2 Methods. More specifically, the present invention relates to the use of transition metal catalysts to catalyze the release of H from ammonia borane and its derivatives 2 Methods. The method of the invention has important applications in the field of hydrogen fuel cells. Background technique [0002] Combustion of hydrogen and oxygen is considered the cleanest energy source available because the only product is water. Scientific institutions around the world have clearly expressed the need for safe storage of hydrogen, which is highly explosive under high pressure. To ensure that hydrogen is available in practical usable quantities, reinforced thick steel walled pressurized gas tanks are required. When transporting, this leads to the need to waste a lot of energy to carry the extra weight required by the hydrogen tank. In addition, there are significant hazards associated with pressurized hyd...

AI Technical Summary

Problems solved by technology

However, all the methods reported so far suffer from a number of potential disadvantages that potentially limit their commercial application

Although the release of hydrogen from ammonia borane is catalyzed by a wide variety of metal complexes, there are still some potential problems that limit commercial applications.

The first is the currently reported high cost issues associated with iridium or rhodium metal catalysts

The second issue is the sensitivity to atmospheric oxygen, which significantly deactivates iridium and rhodium based systems at low levels

This creates a safety hazard and necessitates the use of reaction vessels capable of withstanding significantly higher pressures

Synthesis and further adjustment of ligand systems are difficult and require multiple steps and costly separations

[0012] Finally, for many single-site metal catalysts reported so far, the reversion to the original ammonia borane through regeneration cannot be achieved.

Furthermore, these single-site catalysts do not have the ability to shut down at low hydrogen pressures, creating potentially dangerous stresses, especially if the cells are exposed to elevated temperatures

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