Phyllosilicate-Derived CuNi/SiO₂ Catalysts in the Selective Hydrogenation of Adipic Acid to 1,6-Hexanediol

NiO_x-promoted Cu-based catalysts derived from CuNi phyllosilicates were synthesized, characterized, and tested in the selective hydrogenation of adipic acid to 1,6-hexanediol. The reduction of the CuNi phyllosilicate allows finely dispersed Cu⁰ and Cu⁺ on the surface. The reduced Cu₃₆Ni₅PS catalyst was found to have a higher turnover frequency for the selective hydrogenation of adipic acid than the reduced Cu₄₁PS, Cu₄₀Ni₁PS, and Cu₃₁Ni₁₀PS catalysts. This catalyst is also effective at hydrogenation of succinic acid, glutaric acid, butyric acid, pentanoic acid, and hexanoic acid to their respective alcohols. The higher activity of the reduced Cu₃₆Ni₅PS catalyst is attributed to a higher oxidation state of Cu cations.