Surface functionalization for synergistic catalysis: Silica-alumina- supported cationic indium and organic base for cyanoethoxycarbonylation

A silica-alumina (SiO₂-Al₂O₃) surface possessing both In³⁺ cations and an amine base has been prepared. Surface-functionalized SiO₂-Al₂O₃ was characterized by solid-state ²⁹Si MAS, ¹³C CP/MAS, and ²⁷Al 2D MQ/MAS NMR spectroscopy; X-ray photoelectron spectroscopy; and elemental analysis. The bifunctional surface demonstrates synergistic catalysis for cyanoethoxycarbonylation of aldehyde. Close relationship: A silica-alumina (SiO₂-Al₂O₃) surface possessing both In³⁺ cations and an amine base is described. These two functions on same solid surface act as acidic and basic units in the catalytic cyanoethoxycarbonylation of aldehyde (see picture).