頁籤選單縮合
題 名 | Beckmann Rearrangement of Cyclohexanone Oxime over Borate-Pillared LDHs |
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作 者 | 林振村; 蔡世貞; 鄭淑芬; | 書刊名 | Journal of the Chinese Chemical Society |
卷 期 | 46:5 1999.10[民88.10] |
頁 次 | 頁779-787 |
分類號 | 346.01 |
關鍵詞 | 貝克曼重排; 催化劑; Beckmann rearrangement; Boria; LDH; Pillaring; Catalyst; |
語 文 | 英文(English) |
英文摘要 | Borate-pillared layered double hydroxides (LDHs) were studied as catalysts in vapor-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam under atmospheric pressure. The results were compared with those over the physical admixture of LDH and boria, the co-precipitate of B-Mg-Al hydroxide, and the pristine LDH and boria compounds. Although oxime conversion and caprolactam selectivity declined with time-on-stream over all the catalysts, borate-pillared LDH catalysts could retain activity longer than pure boria or those prepared by other methods. The decay rate however was affected by the Mg/Al ratio, the boron content and the form of LDH precursor used. The LDH itself functioning as a basic catalyst contributed to the formation of side products such as cyclohexanone and 2-cyclohexen-1-one. The physical admixtures of LDH and boria had catalytic properties more close to that of pure boria, which gave high caprolactam selectivities but lost the activity in several hours on stream. The high resistance to decay of the pillared catalysts was attributed to that boria in the interlayer of LDH was stabilized and prevented from structural transformation to a glassy state of no activity. |
本系統中英文摘要資訊取自各篇刊載內容。