Gayapan Krittidech, Sripinun Sirada, Panpranot Joongjai, Praserthdam Piyasan, Assabumrungrat Suttichai
Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Bangkok 10330 Thailand
RSC Adv. 2018 Aug 10;8(50):28555-28568. doi: 10.1039/c8ra04949a. eCollection 2018 Aug 7.
The effects of calcination and pretreatment temperatures of the H-treated WO/SiO catalysts in metathesis of ethylene and 2-butene to propylene were investigated. The results showed that pretreatment with pure hydrogen over the non-calcined catalysts resulted in higher activity and stability than the calcined catalysts, and the hydrogen pretreatment temperature at 650 °C offered the highest 2-butene conversion and propylene selectivity. The calcination of the catalyst before hydrogen pretreatment was proved to be unnecessary. As revealed by various characterization results from N physisorption, XRD, TEM, UV-Vis, Raman, H-TPR, NH-DRIFTS and NH-TPD techniques, activity of the metathesis of ethylene and 2-butene to propylene was related to tungsten dispersion on the support, WO and WO phase composition, and isolated surface tetrahedral tungsten oxide species. The stability of the metathesis reaction was also related to the total acidity and the acid sites of both Brønsted and Lewis acid sites.
研究了经氢处理的WO/SiO催化剂的煅烧温度和预处理温度对乙烯与2-丁烯复分解制丙烯反应的影响。结果表明，在未煅烧的催化剂上用纯氢进行预处理比煅烧后的催化剂具有更高的活性和稳定性，650℃的氢预处理温度能提供最高的2-丁烯转化率和丙烯选择性。事实证明，在氢预处理之前对催化剂进行煅烧是不必要的。通过N物理吸附、XRD、TEM、UV-Vis、拉曼、H-TPR、NH-DRIFTS和NH-TPD技术的各种表征结果表明，乙烯与2-丁烯复分解制丙烯的活性与钨在载体上的分散度、WO和WO相组成以及孤立的表面四面体氧化钨物种有关。复分解反应的稳定性还与总酸度以及布朗斯台德酸和路易斯酸位点的酸位点有关。
