Author Topic: Aq. Wacker with Pd Cluster on TiO2 surface  (Read 1717 times)

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Aq. Wacker with Pd Cluster on TiO2 surface
« on: October 07, 2004, 04:03:00 AM »

Nanoscale Palladium Cluster Immobilized on a TiO2 Surface as an Efficient Catalyst for Liquid-phase Wacker Oxidation of Higher Terminal Olefins

A Pd nanocluster immobilized on a TiO2 surface acted as an efficient catalyst for the liquid-phase Wacker oxidation of higher terminal olefins in the presence of water and CuCl2 under an O2 atmosphere.

References 1) An excellent review of the Wacker oxidation: J. Tsuji, Synthesis, 1984, 369;

J. Tsuji, “Palladium Reagents and Catalysts Innovations in Organic Synthesis,” John Wiley & Sons, New York (1998).

2) Recent examples of the acid-free homogeneous catalyst system for the Wacker oxidation of higher olefins, see, Pd–Cu complexes: a) T. Hosokawa, M. Takano, and S.-I. Murahashi, J. Am. Chem. Soc., 118, 3990 (1996).

PdCl2–Cu(OAc)2: b) A. B. Smith, III, Y. S. Cho, and G. K. Friestad, Tetrahedron Lett., 39, 8765 (1998).

Pd-amine complexes: c) G.-J. ten Brink, I. W. C. E. Arends, G. Papadogianakis, and R. A. Sheldon, Chem. Commun., 1998, 2359.

d) T. Nishimura, N. Kakiuchi, T. Onoue, K. Ohe, and S. Uemura, J. Chem. Soc., Perkin Trans. 1, 2000, 1915.

3) A recent review of the vapor-phase Wacker oxidation of light olefins by heterogeneous catalysts: D. E. De Vos, B. F. Sels, and P. A. Jacobs, Adv. Catal., 46, 1 (2001).

4) Pd complex-immobilized catalysts for the Wacker oxidation of higher olefins in liquid phase, see, PdCl2–CuCl2/pore glass: a) J. P. Arhancet, M. E. Davis, and B. E. Hanson, Catal. Lett., 11, 129 (1991).

PdCl2–CuCl2/N-cyanomethylated polybenzimidazole: b) H. G. Tang and D. C. Sherrington, J. Catal., 142, 540 (1993).

Pd(OAc)2-molybdovanadophosphate/carbon with CH3SO3H: c) A. Kishi, T. Higashino, S. Sakaguchi, and Y. Ishii, Tetrahedron Lett., 41, 99 (2000).

5) a) K. Ebitani, K.-M. Choi, T. Mizugaki, and K. Kaneda, Langmuir, 18, 1849 (2002).

b) K.-M. Choi, T. Akita, T. Mizugaki, K. Ebitani, and K. Kaneda, New J. Chem., in press.

6) I. I. Moiseev, J. Organomet. Chem., 488, 183 (1995).

7) TiO2 was supplied from the Catalysis Society of Japan as JRC-TIO-2 (anatase, BET surface area: 14 m2g?1), and is characterized by its low acidity and basicity compared with other TiO2 reference samples.

8) A typical example for the oxidation of 1-decene catalyzed by the cationic Pd2060/TiO2 is as follows. Into a reaction vessel equipped with a reflux condenser and balloon were placed the cationic Pd2060/TiO2 (0.0394 g, Pd: 0.01 mmol) and CuCl2·2H2O (0.0054 g, 0.03 mmol). After the reaction vessel was filled with O2, N,N-dimethylacetamide (4 mL), H2O (0.5 mL), and 1-decene (0.14 g, 1 mmol) was added. Then, the reaction mixture was vigorously stirred at 80 °C for 2 h. The catalyst was separated by filtration, and GC analysis of the filtrate showed 88% yield of 2-decanone.

9) a) I. W. C. E. Arends and R. A. Sheldon, Appl. Catal., A, 212, 175 (2001).

b) K. Mori, K. Yamaguchi, T. Hara, T. Mizugaki, K. Ebitani, and K. Kaneda, J. Am. Chem. Soc., 124, 11572 (2002).

10) Absence of O2, H2O, or CuCl2·2H2O resulted in less than a 1% yield of 2-decanone.

11) W. H. Clement and C. M. Selwitz, J. Org. Chem., 29, 241 (1964).