کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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42224 | 45916 | 2010 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Salen manganese (III) complexes as catalysts for R-(+)-limonene oxidation Salen manganese (III) complexes as catalysts for R-(+)-limonene oxidation](/preview/png/42224.png)
The epoxidation of R-(+)-limonene using in situ generated dimethyldioxirane (DMD) as the oxidizing agent and four Jacobsen-type catalysts ((R,R)-Jacobsen, (S,S)-Jacobsen, racemic Jacobsen and achiral Jacobsen) was examined. The effect of the amount of KHSO5 and acetone in the catalyzed and un-catalyzed reaction was also assessed. The main reaction products were diepoxide and endocyclic monoepoxide. In the absence of catalyst, the amount of KHSO5 did not significantly influence conversion and selectivity. The catalyst can be segregated to a different phase and separated from the reaction media when the amount of KHSO5 is above the stoichiometric ratio, R-(+)-limonene/KHSO5 = 0.5 mmol/mmol, and acetone/mmol R-(+)-limonene = 2 mL/mmol. However, when the amount of KHSO5 is below the stoichiometric ratio (R-(+)-limonene/KHSO5 = 1.5 mmol/mmol) the catalyst is difficult to separate. Under the reaction conditions of this study, when the catalyst is segregated, no effect of the catalyst chiral center, (R,R)-Jacobsen or (S,S)-Jacobsen, was found on conversion and selectivity. Additionally, the (R,R)-Jacobsen's catalyst proved to be very stable to oxidative degradation.
The epoxidation of R-(+)-limonene using in situ generated dimethyldioxirane (DMD) as the oxidizing agent and four Jacobsen-type catalysts ((R,R)-Jacobsen, (S,S)-Jacobsen, racemic Jacobsen and achiral Jacobsen) was studied. The main reaction products were diepoxide and endocyclic monoepoxide. The catalyst can be segregated to a different phase and separated from the reaction media when the amount of KHSO5 is above the stoichiometric ratio.Figure optionsDownload high-quality image (63 K)Download as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 373, Issues 1–2, 31 January 2010, Pages 57–65