IEC 170 |
| Lin Haiqiang1, Yuan Youzhu1, Lin Huamin2, and Wan Huilin1. (1) Department of Chemistry, State key laboratory for physical chemistry of solid surfaces, Xiamen University, Xiamen, 361005, China, (2) Department of Chemistry, Hainan Normal University, haikou, 570000, China |
| An efficient micellar phase-transfer catalytic system of H3PW12O40/CTMABr was found to catalyze H2O2 oxidation of cyclohexene to adipic acid with a yield of 96.2%. Acidic condition is essential for the reaction, not only lying in that it enables epoxides undergo hydrolytic ring cleavage readily, but also ensuring the formation of stable peroxo species which favors the efficient utilization of H2O2. Raman and kinetic studies show that sept-coordinated complexes [M2O3(O2)4(H2O)2] in acidic media possess much better thermal stability than the octo-coordinated complexes [W(O2)4]2- under neutral condition. Moreover, Cl- was proved to be harmful for the stability of peroxo tungstate species probably due to strong competition on tungsten atom with peroxo oxygen. CTMABr is a prosperous micellar phase-transfer reagent for cyclohexene H2O2 oxidation and the dosage of CTMABr could be reduced to a low level of 0.2 mol%. Substitution of bromides for chlorides also is beneficial to increase the stability of peroxo species and oxidative efficiency of H2O2. |
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General Poster Session
5:00 PM-7:00 PM, Tuesday, March 25, 2003 Convention Center -- Hall G, Poster
Division of Industrial and Engineering Chemistry |