Collect. Czech. Chem. Commun. 1990, 55, 686-694

Reactions of aromatic radical-anions and ethyllithium with silica gel and Brönsted acids

Jan Kratochvíla, Zdeněk Salajka, Antonín Kazda, Zbyněk Kadlc and Mihnea Gheorghiu

Chemopetrol, Research Institute of Macromolecular Chemistry, 656 49 Brno


Electric conductivities of radical-anions prepared from several aromatic compounds (biphenyl, naphthalene, benzophenone, anthracene, phenanthrene) and sodium in tetrahydrofuran have been measured and a suitability of radical-anions for titration of silica gel and acid impurities in liquid media have been investigated. The reactivity of the radical-anions and ethyllithium with acidic hydrogen of silica gel hydroxy groups is approximately equal in spite of substantial differences in structure and bonding character of the above compounds. Highest amounts of radical-anions and ethyllithium are decomposed by thermally non-activated silica gel (1.7 to 1.8 mmol g-1 for Davison, grade 952). With the increasing temperature of dehydration of silica gel (200-900 °C), the amount of decomposed organometallic compounds decreases approximately linearly.