Alkylation of anions on solid inorganic supports : an interpretation of the function of the supports

In the anionic alkylation (CH₃ CO₂K + n C₈ H₁₇ Br) on solid inorganic supports, silica impregnated with cationic surfactant appears to be as effective as alumina, while silica bearing ammonium groups covalently bonded to the support (SPHEROSIL QMA) exhibits increased effectiveness. An interpretation based upon the superficial charge of the solid surfaces is proposed.