The oxidation of alkenes and alcohols with hydrogen peroxide (H_2O_2) and molecular oxygen, is quite an interesting objective for both academic and industrial fields. In this paper, we focused on polyoxometalates and microporous transition metal carboxylates as oxidation catalysts. For H_2O_2-based epoxidation reactions catalyzed by dimeric mono, di, and trititanium (IV)-substituted Keggin polyoxotungstates, trititanium (IV)-substituted Keggin polyoxotungstate was the most active because it exhibited the fastest formation rate of active hydroperoxotitanium (IV) intermediate. Furthermore, we investigated a novel method for the grafting reaction of transition metal-substituted polyoxometalates onto a silica surface. Keggin-type vanadium(V)-substituted polyoxomolybdate (PMoV) was electrostatically anchored to a modified silica surface having cationic ammonium moiety. The PMoV-grafted silica material exhibited activities higher than those of homogeneous PMoV reactions for the oxidation of various alcohols with 1 atm dioxygen in the presence of isobutyraldehyde (IBA). Microporous copper(II) carboxylates showed unique activities for the oxidation of alcohols with H_2O_2 in a heterogeneous system, in which a green-colored species, H_2[Cu_2^<II,II>(OOCC_6H_10COO)_2(O_2)]・H_2O was one of the active oxidizing intermediates.
雑誌名
Science Journal of Kanagawa University
巻
17
ページ
31 - 37
発行年
2006-05-25
ISSN
1880-0483
書誌レコードID
AA12068302
著者版フラグ
publisher
その他の言語のタイトル
Polyoxometalates and Microporous Transition Metal Carboxylates: Synthesis, Characterization, and Oxidation Catalysis