Pulse Radiolysis Investigations of Solvation Effects on Arylmethyl Cation Reactivity in Supercritical Fluids
| Autor: | Jianwei Zhang, John E. Chateauneuf, Karen A. Connery, Joan F. Brennecke |
|---|---|
| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry. 100:12394-12402 |
| ISSN: | 1541-5740 0022-3654 |
| DOI: | 10.1021/jp961033x |
| Popis: | Pulse radiolysis has been used to measure the influence of supercritical fluid and cosolvent solvation on arylmethyl cation reactivity in supercritical fluoroform (CHF3) and ethane (C2H6). Ion−neutral reactivity was investigated for the reaction of benzhydryl cation (Ph2C+H) with tetramethylethylene (TME) in CHF3 at 35 and 50 °C, and with triethylamine (TEA) in CHF3 at 35 and 70 °C, and for the reaction of 4,4‘-dimethoxybenzhydryl cation ((4-MeOPh)2C+H)) with TEA in CHF3 at 35 and 70 °C, and with TEA in C2H6 at 35 °C. The effect of pressure on the bimolecular rate constants (kbi) for these nucleophilic reactions was investigated over significant fluid density ranges, along the isotherms indicated, and in each case was found to decrease in magnitude with an increase of pressure (solvent density). The reactivity observed was analyzed in terms of the influence of bulk solvent dielectric constant on kbi, the comparison of the pressure effect on kbi with that predicted from transition state theory, and the inf... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|