Alkali metal zeolites oligomerization

Synthesis of silica-based materials with controlled skeleton structures, such as zeolites, requires controlling the structure of oligomeric silicate species at the first reaction step. Organic quaternary ammonium ions, which are known as organic templates in zeolite synthesis (1 ), have a role in making up the specific structures of silicate anions, whereas silicate anions randomly polymerize in aqueous solutions containing alkali metal ions, resulting in the presence of silicate anions with different structures. [Pg.140]

The work presented here was aimed at establishing the influence of different alkali metal cations on the distribution of silicate anions in aqueous solutions such as those used in zeolite synthesis. Changes in the extent of silicate oligomerization were identified... [Pg.223]

The suggested ionic mechanism was used to explain the activity and selectivity behaviour in the oligomerization of olefins over alkali metal ion-exchanged zeolites. In olefin oligomerization, the activity pattern for the alkali metal ion forms in zeolites is inversely proportional to the ionic radius, e.g. Li > Na" >... [Pg.241]

Condensation Oligomeric dimethylsiloxane-diol H2SO4, HCl, tin dicarboxylates, hydroxides of alkali metals or zeolite (7, 9-11)... [Pg.413]