Preservation of Methane Hydrates Prepared from Dilute Electrolyte Solutions

The anomalous or self-preservation of methane hydrate at atmospheric pressure and temperatures below the ice point was investigated to determine whether this phenomenon might have applications in the storage and transportation of natural gas. Particular attention was paid to the effects of dilute electrolytes, as the presence of impurities in water is unavoidable in commercial transportation processes. The presence of electrolytes had a marked effect on the decomposition kinetics of methane hydrate at temperatures between 243 and 269 K. It was also found that chloride and sulfate ions may exhibit greater effects than do sodium and magnesium ions

Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand

Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of <i>gem</i>-dichromio­methane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive <i>gem</i>-dimetallo­alkane species. The isolated <i>gem</i>-dichromio­methane complex acted as a storable silyl­methylidene carbene equivalent, with reactivity that could be changed dramatically upon addition of a Lewis acid (ZnCl₂) and a base (TMEDA) to promote both silyl­alkyl­iden­ation of polar aldehydes and silyl­cyclo­propan­ation of nonpolar alkenes. Identification of a key reactive species also identified the catalytic version of these transformations and provided insights into the reaction mechanism. In contrast to Simmons–Smith cyclo­propan­ation, the real reactive species for the current cyclo­propan­ation was a chromio­carbene species, not a chromium carbenoid species

Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand

Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of <i>gem</i>-dichromio­methane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive <i>gem</i>-dimetallo­alkane species. The isolated <i>gem</i>-dichromio­methane complex acted as a storable silyl­methylidene carbene equivalent, with reactivity that could be changed dramatically upon addition of a Lewis acid (ZnCl₂) and a base (TMEDA) to promote both silyl­alkyl­iden­ation of polar aldehydes and silyl­cyclo­propan­ation of nonpolar alkenes. Identification of a key reactive species also identified the catalytic version of these transformations and provided insights into the reaction mechanism. In contrast to Simmons–Smith cyclo­propan­ation, the real reactive species for the current cyclo­propan­ation was a chromio­carbene species, not a chromium carbenoid species