Tethered Pd-complex on solid support: catalyst for acid-free carbonylation reactions

Abstract

Palladium complex [Pd(pyca)(PPh₃)(OTs)] has been immobilized on solid matrices having ordered framework and high surface area as zeolite NaY (surface area ~700 m² g^-1), using phosphotungstic acid [H₃PW₁₂O₄₀, xH₂O] as the molecular tether to form highly stable catalyst materials. The materials were thoroughly characterized using numerous techniques such as ³¹P CP-MAS NMR, XPS, powder XRD, SEM, etc. to confirm the immobilization and determine the state of the complex after tethering. Carbonylation of substituted olefins and alcohols was performed using this tethered catalyst without the addition of any free acid (protic/aprotic) promoter, with highly promising results. Thus, we can achieve dual advantages of efficient immobilization and partially promoter-free carbonylation catalysts, which is a substantial advancement in carbonylation catalysis.