KINETICS OF SOLVATED ELECTRONS IN REACTION WITH HEXAMETHYLPHOSPHORIC TRIAMIDE

Solvated electrons, e(s)(-), have been generated in hexamethylphosphor ic triamide (HMPA) by chemical and electrochemical means, When Na meta l was used to release e(s)(-), two distinct bands, already reported in the literature, appeared in the absorption spectrum of the solution, which rapidly turned red-brown and decomposed according to irreproduci ble complex kinetics which could not be analysed. When Li was used ins tead of sodium, a single broad band extending into the IR region devel oped and later decayed obeying consistently first-order kinetics in ab sorbance. Kinetic rate constants are reported and half-lives at ambien t temperature were about 1 h duration. A systematic study of the disap pearance of solvated electrons in HMPA was carried out at several temp eratures (from 7 to 27 degrees C) and an activation energy (85-89 kJ m ol(-1)) is estimated both in the absence and in the presence of lithiu m perchlorate. However, the overall reaction rate is markedly increase d in the presence of Li+; a mechanism is proposed to account for this lithium salt effect.