โ Scribed by Vaibhav B. Valodkar; Gopal L. Tembe; Marayil Ravindranathan; H.S. Rama
No coin nor oath required. For personal study only.
A synthetic strategy was developed to anchor an amino acid L-valine on to styrene-divinylbenzene co-polymer beads with 8% and 6% cross linking. The polymeric ligands containing bidentate N,O donor sites were treated with a solution of ruthenium(III) chloride to form the metal complex on the support. These immobilized Ru(III) complexes were characterized by elemental analysis, FT-IR, UV-visible diffuse reflectance, ESR, SEM and thermal analysis. The catalytic epoxidation of styrene, norbornylene, cyclooctene, and cyclohexene were investigated using the supported catalysts in the presence of tert.-butyl hydroperoxide as the terminal oxidant. Selective epoxide formation was observed with norbornylene and cis-cyclooctene whereas in the case of styrene the corresponding epoxide, benzaldehyde and acetophenone were obtained. Amongst the olefins screened, good activity was observed in the case of cyclohexene. The effect of various reaction parameters as well as some aspects of catalyst recycling and possible mechanistic pathways has also been investigated.
๐ SIMILAR VOLUMES
A new methodology has been developed for the catalytic epoxidation of cyclic vinylsilanes using a ruthenium(II) bisoxazoline complex 2 with molecular oxygen. An attempt has been made to understand the role of -SiMe 3 group on the rate of epoxidation process.