Epoxidation of alkenes catalyzed by heteropolyoxometalate as pillars in layered double hydroxides

✍ Scribed by Y Watanabe; K Yamamoto; T Tatsumi

• Book ID: 104424407
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 171 KB
• Volume: 145
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(99)00012-6

✦ Synopsis

The epoxidation of alkenes with hydrogen peroxide or molecular oxygen, in the presence of aldehyde catalyzed by Ž . Ž . heteropolyoxometalate HPOM salts and layered double hydroxides LDHs containing HPOM anions as pillars, has been investigated. In the case of oxidation with hydrogen peroxide, a lacunary Keggin-ion, SiW O 8y , was more active than 11 39

SiW O 4y . For this reaction system using hydrogen peroxide, intercalated SiW O 8y showed higher stability in structure 12 40 11 39

and activity than free K SiW O . For the oxidation using molecular oxygen and aldehyde, SiW O 4y showed higher 8 1 1 3 9 12 40 activity than SiW O 8y . It was confirmed that SiW O 4y was intercalated between the brucite-type layers of the LDHs 11 39 12 40 without change in structure. Ni-containing LDHs without any interstitial polyoxometalate showed high activity for the oxidation of cyclohexene with the combination of O and aldehyde.