Rhodium complex encapsulated functionalized hexagonal mesoporous silica for heterogeneous hydroaminomethylation

HRh(CO)(PPh3)(3) complex was encapsulated into the pores of amino functionalized hexagonal mesoporous silica. The catalyst was characterized by physico-chemical techniques like P-XRD, P-31-CPMAS NMR, FT-IR, SEM, ICP and N-2 adsorption analysis. The catalyst was active for hydroaminomethylation and a variety of alkenes and amines were used as reactants for hydroaminomethylation. The catalyst afforded to achieve 100% conversion with high (>95%) selectivity to corresponding amines. Parametric variations were performed by taking 1-hexene and morpholine as representative reactants for the study of catalyst amount, temperature, pressure and 1-hexene:morpholine ratio. Significant amounts of aldehydes and enamines were observed during the course of the reaction indicating that there could be two possible rate determining steps. The catalyst was effectively recycled up to five times without much loss in its activity and selectivity. (C) 2012 Elsevier B.V. All rights reserved.