Study of Cu-ZnO-Al2O3 based catalysts promoted by Sc2O3 for dehydrogenation of cyclohexanol to cyclohexanone

摘要 环己酮是化学工业的重要中间体；其重要应用实例之一，是用作制造己内酰胺的原料，后者是尼龙-6的单体。环己酮主要经由环己醇催化脱氢制得。就工业观点而言，在常压下，该多相催化气相脱氢过程受高度吸热（∆H=65kJ/mol）和热力学平衡限制。 催化剂在环己醇脱氢制环己酮反应过程中起至关重要的作用。现行的环己醇脱氢催化剂体系有两种：高温下(673~723K)使用的ZnO/CaCO3催化剂和低温下(473~523K)使用的Cu系催化剂。然而该脱氢过程受到热力学平衡和Cu催化剂在553K就容易烧结的限制。因此，提高催化剂的低温活性和操作稳定性是Cu基催化剂开发中亟待解决的关键问题。 ...Abstract Cyclohexanone is an important intermediate of the chemical industry. Among its different applications, cyclohexanone is used as raw material for caprolactam manufacture, which is the monomer of nylon 6. Cyclohexanone is mainly produced through the catalytic dehydrogenation of cyclohexanol. From an industrial point of view, the heterogeneous catalytic gas-phase dehydrogenation, at atmosph...学位：理学硕士院系专业：化学化工学院_物理化学(含化学物理)学号：2052011115157

A Novel Sc-promoted CuO-ZnO-Al_2O_3 Catalyst for Dehydrogenation of Cyclohexanol to Cyclohexanone

用SC2O3作为促进剂,研发出一种高效新型SC2O3促进的Cu-znO-Al2O3基催化剂(记为CuIznJAlk-XSCX),考察其对环己醇脱氢制环己酮的催化性能.实验结果显示,在组成经优化的Cu6zn3Al0.7SC0.3催化剂上,常压,523 k,n(C6H11OH)∶n(n2)=1∶19和空速(gHSV)=43 200Ml/(H·g)的反应条件下,环己醇脱氢的转化率达53.7%,产物环己酮的时空产率为5 344Mg/(H·g),这2个值均为不含SC2O3的基质催化剂Cu6zn3Al1的相应值(42.4%,4 222Mg/(H·g))的1.27倍.催化剂的表征结果显示,SC2O3的修饰调变作用可能是由于SC2O3在znO晶格中高的溶解度.少量SC2O3在znO晶格中的溶解在znO表面产生阳离子空位形式的SCHOTTky缺陷,通过这些表面阳离子空位接纳Cu+离子使Cuy0-Cu+原子簇得以稳定化.这有助于抑制催化活性Cuy0纳米颗粒的团聚烧结,保持Cu组分的高分散度,于是显著地提高催化剂的活性和操作稳定性.该催化剂具有应用前景.A type of Sc2O3-promoted Cu-ZnO-Al2O3 catalyst was developed.The catalyst displays excellent performance for dehydrogenation of cyclohexanol to cyclohexanone.Over a Cu6Zn3Al0.7Sc0.3catalyst under the reaction condition of atmospheric pressure,523 K,n(C6H11OH)∶n(N2)=1∶19and GHSV=43 200 mL/(h·g),the conversion of cyclohexanol dehydrogenation reached53.7%,with the STY of cyclohexanone being 5 344mg/(h·g);both values were 1.27 times of those obtained with the Cu-ZnOAl2O3 catalyst not containing Sc2O3,42.4% and 4 222 mg/(h·g).Characterization of the catalyst revealed that the pronounced modification action of Sc3+may be due to the high solubility of Sc2O3 in the ZnO lattice.Solution of a small amount of Sc2O3 in the ZnO lattice resulted in the formation of Schottky defects in the form of cationic vacancies at the surface of ZnO,where the Cuy0-Cu+clusters can be better stabilized through the Cu+accommodated at the surface vacant cation-sites.This would be conducive to inhibiting the aggregation and sintering of the catalytically active Cuy0nano-particles and preserving high dispersion degree of Cu composition,so that the activity and operating stability of the catalyst were markedly improved.国家重点基础研究发展计划(973)项目(2011CBA00508); 优秀国家重点实验室基金项目(20923004); 教育部创新团队项目(IRT1036