کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6456494 | 1419919 | 2017 | 7 صفحه PDF | دانلود رایگان |
- Sandwich-type Bâαâ[M4(H2O)2(PW9O34)2]nâ (M = CoII, MnII, FeIII) polyoxometalates.
- Oxidation of limonene, geraniol, linalool, carveol, and cyclooctene.
- Oxidation with 30% (w/w) aqueous hydrogen peroxide, in acetonitrile.
- The main/unique oxidation pathway for terpenoids and cyclooctene is epoxidation.
Catalytic efficiency of tetrabutylammonium salts of sandwich tungstophosphates Bâαâ[M4(H2O)2(PW9O34)2]nâ, M = CoII, MnII, FeIII, was studied in the oxidation of (R)-(+)-limonene, geraniol, linalool, linalyl acetate, carveol, and cis-cyclooctene with hydrogen peroxide, in acetonitrile. Oxidation of (R)-(+)-limonene gave limonene-1,2-diol as main product. Epoxidation of linalool takes place preferentially at the more substituted 6,7-double bond, the corresponding 6,7-epoxide reacting further, yielding furano- and pyrano-oxides, via intramolecular cyclization. Oxidation of linalyl acetate occurred preferentially at the more substituted 6,7-double bond for Mn4(PW9)2, affording 6,7-epoxide at 82% selectivity. Linalyl acetate 1,2-epoxide was the major product with 51% and 77% selectivity for Co4(PW9)2 and Fe4(PW9)2, respectively. Oxidation of carveol occurred with very good conversions in the presence of Mn4(PW9)2, Co4(PW9)2 and Fe4(PW9)2, yielding carvone and carveol 1,2-epoxide in similar amounts. Oxidation of cis-cyclooctene gave only the epoxide, while oxidation of geraniol at room temperature afforded 2,3-epoxygeraniol as the major product.
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Journal: Journal of Molecular Catalysis A: Chemical - Volume 426, Part B, January 2017, Pages 593-599