β-picoline部分氧化生成菸鹼酸：釩鎢交互作用的角色

Formation Of Nicotinic Acid Via β-picoline Partial Oxidation: Role Of Vanadia-Tungstenia Interaction

文尚彬(Wun, Shang Bin)

指導教授 ： 張仁瑞

國立中正大學/理學院/化學暨生物化學系/碩士(2012年)

摘要

TiO2-SiO2觸媒催化氧化β-picoline形成菸鹼酸，嫁接氧化鎢用以研究釩鎢交互作用對催化行為的效應。催化性能測試以連續式固定床進行並利用Power-law模型校正反應數據，PXRD、V K-edge EXAFS光譜和程溫還原用來鑑定觸媒結構，結構分析結果配合反應數據以說明V2O5-WOx所扮演的角色。PXRD證實WV2O6合金的形成，該合金說明了氧化釩與氧化鎢間交互作用的存在，EXAFS在3.5 Å出現新的吸收峰再度確認此現象。釩鎢交互作用同時增加反應巨觀活化能與頻率因子使釩鎢鈦觸媒的轉化率較為之低。氧化釩的程溫還原在300度以下並無顯著的不同，直到450度以上才有明顯的變化。此外，釩鎢交互作用大幅增加β-picoline部分氧化反應的操作溫度，菸鹼酸選擇性在反應溫度提升至340度時大幅增加；而不具交互作用的觸媒其選擇性則隨反應溫度提升而下降。

關鍵字

菸鹼酸 ； 部分氧化 ； 釩鎢交互作用

並列摘要

TiO2-SiO2 catalysts were used for catalytic oxidation of β-picoline to nicotinic acid. Tungsten oxide was added to the catalysts in order to study the effects of vanadia-tungstenia interaction on catalysis. Catalytic performance tests were carried out in a continuous fixed bed. A simple power-law was used to model with kinetic data. P-XRD V K-Edge EXAFS and TPR spectrum were used to characterize the structure of the catalysts. The results were correlated with kinetic data to illustrate the role of vanadia-tungstenia interactions. Formation of WV2O6 crystalline evidenced by PXRD proves the existence of the interaction, which was further confirmed by EXAFS peak appearing at 3.5 Å. The interaction increases both apparent activation energy and frequency factor. As a consequence, the conversion of vanadia-tungstenia catalyst is lower than that vanadia catalyst at reaction temperature lower than 300 ℃, while has no significant difference at reaction temperature higher than 320 ℃. Furthermore, the interactions greatly increase the operation temperature of β-picoline partial oxidation. The selectivity to nicotinic acid increase with reaction temperature up to 340 ℃for the catalyst with vanadia-tungstenia interaction. In contrast, for the catalyst without vanadia-tungstenia interactions, the selectivity decreases with increasing reaction temperature.

並列關鍵字

Nicotinic Acid ； Partial Oxidation ； Vanadia-tungstenia interaction

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