Direct Propylene Epoxidation over RuO2–CuO–NaCl–TeO2–MnOx/SiO2 Catalysts: Optimized Operating Conditions and Catalyst Characterization

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• 作者：Anusorn SeubsaiPhotchanan Phon-in ; Thanaphat Chukeaw ; Chalinee Uppala ; Paweena Prapainainar ; Metta Chareonpanich ; Bahman Zohour ; Daniel Noon ; Selim Senkan
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：56
• 期：1
• 页码：100-110
• 全文大小：856K
• ISSN：1520-5045

文摘

Multimetallic catalysts of RuO₂–CuO–NaCl–TeO₂–MnO_x supported on SiO₂ were investigated for the direct-gas-phase epoxidation of propylene to propylene oxide (PO) using molecular oxygen under atmospheric pressure. Four operating variables (reactor temperature, O₂ to propylene feed gas volume ratio, reactants to carrier gas volume ratio, and total feed gas flow rate) were studied using the Box–Behnken design, which enabled the achievement of a relatively high PO formation rate at 1507 g_PO h^–1 kg_cat^–1 with PO selectivity of 25.3% and propylene conversion of 5.9% at 1 h of time on stream. The optimized conditions were a reactor temperature of 297 °C, a O₂/C₃H₆ ratio of 11.95, a (O₂ + C₃H₆)/He ratio of 0.24, and a total feed gas flow rate of 36 cm³ min^–1. The physical and chemical properties were characterized using various techniques that revealed that the crystallinity of RuO₂ and CuO, the close proximity of RuO₂ and CuO, and the surface’s acidity are crucial for PO production. NaCl plays a key role in reducing CO₂ combustion. TeO₂ and MnO_x enhanced the active sites that facilitate PO production.