Supercritical carbon dioxide and poly (ethylene glycol): An environmentally benign biphasic solvent system for Wacker reaction

ORGN 205

Liang-Nian He, heln@nankai.edu.cn, Jin-Quan Wang, jqwang@mail.nankai.edu.cn, Fei Cai, feicai@nankai.edu.cn, Er Wang, ewang@mail.nankai.edu.cn, and Jie-Sheng Tian, jstian@mail.nankai.edu.cn. Institute of Elemento-Oragnic Chemistry, Nankai University, Weijin Rd. 94, Tianjin, 300071, China
A simple and efficient PdCl2/CuCl catalyzed aerobic oxidation of styrene has been successfully developed in a biphasic solvent system consisting of scCO2 and PEG. High acetophenone yield (88%) and styrene conversion (100%) were obtained at 60 ¡ãC under 15 MPa in 24 h using O2 as an oxidant. It was found that PEG matrix effectively stabilized the catalysts and the unique solubility and mass-transfer properties of scCO2 improved the selectivity to acetophenone. Notably, the CO2 pressure dramatically influenced the selectivity. Moreover, the products were separated from the PEG phase via simple decantation after the CO2 venting. The catalyst system immobilized in a PEG matrix was recycled and reused. The styrene oxidation smoothly performed even in pure CO2. The possible mechanism of styrene oxidation in scCO2/PEG biphasic solvent system was also proposed.

 

Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006