K-CuZrO2催化剂上乙醇制备2-戊酮的研究

Study on the formation of 2-pentanone from ethanol over K-CuZrO2 catalysts

    摘要
  • 摘要: 制备了不同Cu含量的K-CuZrO2催化剂。以乙醇缩合制备2-戊酮为探针反应，考察了催化剂的催化性能并对反应机理进行了探索；采用BET、XRD、H2-TPR、CO2-TPD、TEM以及XPS等表征技术对催化剂的体相结构、性质进行了研究。结果表明，当Cu含量为9%时，乙醇转化率达到极大值(99.5%)，这是由于此时催化剂中各组分分散较好，CuO-ZrO2之间存在较强的相互作用，促进了CuO的还原，使催化剂表面Cu比表面积最大；2-戊酮选择性达到最大值（35.0%），是由于催化剂表面适合缩合反应的中等强度碱性中心碱性最强。通过对反应中间物种分析，推测了K-CuZrO2催化剂上2-戊酮的形成过程：乙醇首先脱氢形成乙醛，之后两分子乙醛经缩合、分解得到丙酮，丙酮进一步与乙醛反应形成目标产物2-戊酮。

     

    Abstract: A series of K-CuZrO2 catalysts with different Cu contents were prepared. The catalytic performance and reaction mechanism of 2-pentanone from ethanol condensation were investigated. The structure and properties of the catalysts were studied by N2 sorption, XRD, H2-TPR, CO2-TPD, TEM and XPS. The results showed that when the content of Cu was 9%, the conversion of ethanol reached the maximum (99.5%) due to the strong interaction between CuO and ZrO2 which promoted the reduction of CuO and resulted in the largest specific surface area of Cu on the catalyst surface. The selectivity of 2-pentanone reached the maximum (35.0%) because the strongest basicity related to medium-strength basic sites of the catalyst surface were suitable for the condensation reaction. The formation of 2-pentanone on K-CuZrO2 catalyst was speculated on the basis of the analysis of intermediates: ethanol was dehydrogenated to form acetaldehyde. Then, the acetaldehyde was condensed and decomposed to acetone followed by reaction with acetaldehyde to form 2-pentanone.

     

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