# Reactional Processes on Osmium-Polymeric Membranes for 5-Nitrobenzimidazole Reduction.
> オスミウム含有高分子膜における5-ニトロベンズイミダゾールの水素還元反応プロセスの検討


## Abstract

This study describes the fabrication of composite membranes in which metallic osmium is deposited in situ onto three types of polymer supports—cellulose acetate, polysulfone, and polypropylene hollow fiber membranes—by reducing osmium tetroxide dissolved in tert-butyl alcohol with molecular hydrogen gas. The resulting osmium-polymer (Os-P) composite membranes were characterized using a comprehensive suite of analytical techniques including SEM, HR-SEM, EDAX, FTIR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The catalytic performance of these membranes was evaluated through the reduction of 5-nitrobenzimidazole to 5-aminobenzimidazole using molecular hydrogen as the reductant. A proposed mechanistic pathway for this nitro-to-amino transformation within the Os-P membrane reaction system is also discussed, highlighting the dual role of the membrane in simultaneously facilitating separation and chemical conversion.

### Mechanism

Osmium tetroxide is reduced by molecular hydrogen in tert-butyl alcohol to deposit metallic osmium directly onto the polymer membrane surface. The resulting osmium catalyst activates molecular hydrogen, enabling the selective reduction of the nitro group of 5-nitrobenzimidazole to yield 5-aminobenzimidazole.

## Bibliographic

- **Authors**: Nechifor AC, Goran A, Grosu VA, Pîrțac A, Albu PC, Oprea O, et al.
- **Journal**: Membranes (Basel)
- **Year**: 2021 (2021-08-17)
- **PMID**: [34436396](https://pubmed.ncbi.nlm.nih.gov/34436396/)
- **DOI**: [10.3390/membranes11080633](https://doi.org/10.3390/membranes11080633)
- **PMC**: [PMC8400646](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8400646/)
- **Study type**: other
- **Delivery route**: in vitro
- **Effect reported**: not assessed

## Delivery context

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 34436396. https://h2-papers.org/en/papers/34436396
> **Source**: PubMed PMID [34436396](https://pubmed.ncbi.nlm.nih.gov/34436396/)