Surface Transformation of Methane–Ethane sI and sII Clathrate Hydrates
| Autor: | Steven F. Dec |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Chemistry
Inorganic chemistry Clathrate hydrate Carbon-13 NMR Decomposition Methane Surfaces Coatings and Films Electronic Optical and Magnetic Materials Gas phase chemistry.chemical_compound General Energy Surface transformation Physical chemistry Steady state (chemistry) Physical and Theoretical Chemistry Hydrate |
| Zdroj: | The Journal of Physical Chemistry C. 116:9660-9665 |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | The reaction of methane, ethane, and water to form structure I (sI) and structure II (sII) clathrate hydrates at 268 K was studied using solid-state 13C NMR. The reaction can be described in terms of four stages: stage 1, the simultaneous formation of methane–ethane sI and sII clathrate hydrates; stage 2, cessation of sI hydrate formation and enhanced sII hydrate formation; stage 3, decomposition of sI hydrate and continued enhanced sII hydrate formation; stage 4, approach to a final steady state of the system. The rates of formation and decomposition of the various methane and ethane sites obtained from analysis of the time-resolved 13C MAS NMR intensity data provide strong evidence that the sI ↔ sII transformation occurs at surfaces and is dominated by two simultaneous reactions; methane–ethane sI hydrate decomposes to gas phase methane, gas phase ethane, and water while forming methane–ethane sII hydrate from gas phase methane, gas phase ethane, and water. The results of a 2D exchange 13C MAS NMR exper... |
| Databáze: | OpenAIRE |
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