NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Air oxidation of hydrazine. 1. Reaction kinetics on natural kaolinites, halloysites, and model substituent layers with varying iron and titanium oxide and O- center contentsAir oxidation of hydrazine was studied by using a group of kaolinites, halloysites, and substituent oxides as models for the tetrahedral and octahedral sheets. The rate was found to be linear with oxygen. The stoichiometry showed that oxygen was the primary oxidant and that dinitrogen was the only important nitrogen-containing product. The rates on kaolinites were strongly inhibited by water. Those on three-dimensional silica and gibbsite appeared not to be. That on a supposedly layered silica formed from a natural kaolinite by acid leaching showed transitional behavior--slowed relative to that expected from a second-order reaction relative to that on the gibbsite and silica but faster than those on the kaolinites. The most striking result of the reaction was the marked increase in the rate of reaction of a constant amount of hydrazine as the amount of clay was increased. The increase was apparent (in spite of the water inhibition at high conversions) over a 2 order of magnitude variation of the clay weight. The weight dependence was taken to indicate that the role of the clay is very important, that the number of reactive centers is very small, or that they may be deactivated over the course of the reaction. In contrast to the strong dependence on overall amount of clay, the variation of amounts of putative oxidizing centers, such as structural Fe(III), admixed TiO2 or Fe2O3, or O- centers, did not result in alteration of the rate commensurate with the degree of variation of the entity in question. Surface iron does play some role, however, as samples that were pretreated with a reducing agent were less active as catalysts than the parent material. These results were taken to indicate either that the various centers interact to such a degree that they cannot be considered independently or that the reaction might proceed by way of surface complexation, rather than single electron transfers.
Document ID
20040090064
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Coyne, L.
(San Jose State University California 95192, United States)
Mariner, R.
Rice, A.
Date Acquired
August 21, 2013
Publication Date
January 1, 1991
Publication Information
Publication: Langmuir : the ACS journal of surfaces and colloids
Volume: 7
Issue: 8
ISSN: 0743-7463
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NCC2-153
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 52-20
NASA Discipline Exobiology
NASA Program Exobiology
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available