Selective Synthesis of Methanol and Higher Alcohols over Cs/Cu/ZnO/Al2O3 Catalysts

详细信息    查看全文

• 作者：Jie Sun ; Shaolong Wan ; Fen Wang ; Jingdong Lin ; Yong Wang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：54
• 期：32
• 页码：7841-7851
• 全文大小：552K
• ISSN：1520-5045

文摘

A variety of catalysts for higher alcohol synthesis from syngas have been under development for potential commercial application, which are still facing challenges, including poor carbon efficiency due to low selectivity to desired products. In this contribution, we systematically studied the effects of temperature, loading of K and Cs, space velocity, and CO₂ addition on the alkali-promoted Cu/ZnO/Al₂O₃ catalysts in order to achieve a high yield of desired higher alcohol products. Our particular focus was to maximize the carbon efficiency by restricting the amount of undesired byproducts, such as lower alkanes and CO₂ that could be formed. Among K and Cs promoted Cu/ZnO/Al₂O₃ catalysts studied, Cs-promoted Cu/ZnO/Al₂O₃ catalysts exhibit better performance to higher alcohols and higher carbon efficiency than K-promoted counterparts under similar conditions studied. 1.64 mol % Cs-promoted Cu/ZnO/Al₂O₃ catalyst achieves the highest selectivity to higher alcohols (24.9%) at a CO conversion of 41.6% under 290 掳C, 1875 mL g^鈥?_cat h^鈥?, 5.4 MPa. The presence of a small amount of CO₂ of 2.5 mol % in the feed has negligible effect on the productivity of higher alcohols but significantly suppresses the formation of CO₂ byproduct. With the further increase of CO₂ in the feed, the formation of CO₂ can be further suppressed but at the expense of productivity loss of higher alcohols, which is probably due to the neutralization of surface Cs sites. The best carbon efficiency can be achieved at 8% mol CO₂ in the feed.