微乳法制备纳米Ru/NaY催化剂及其催化对苯二酚加氢

采用曲拉通X-100(Triton X-100)/正己醇/正庚烷/RuCl_3·3H_2O水溶液构成微乳液,以水合肼为还原剂,制备了纳米Ru颗粒,再破乳将其负载于NaY分子筛得到M-Ru/NaY催化剂.通过XRD、BET、XPS、SEM、TEM及DSC分析方法对催化剂进行了表征.表征结果表明,M-Ru/NaY催化剂具有金属钌平均粒径小,分布均匀,高度分散等优点.以对苯二酚加氢制1,4-环己二醇为探针反应,对微乳法和传统浸渍法制备的催化剂活性和选择性进行了比较,深入研究了催化剂用量,反应温度,氢气压力对对苯二酚加氢活性的影响及最佳反应时间的确定.实验结果表明,M-Ru/NaY催化剂在反应温度150℃,氢气压力4.0 MPa,m(M-Ru/NaY)∶m(对苯二酚)=0.2∶1,溶剂为异丙醇,此条件下反应30 min,对苯二酚转化率为100%,1,4-环己二醇的选择性高达92.6%.还考察了M-Ru/NaY催化剂的稳定性.最后,探讨了对苯二酚加氢反应路径.

Preparation of Ru/NaY Nanoparticle Catalysts by Microemulsion Method for Catalytic Hydrogenation of Hydroquinone

Using TritonX-100,n-hexanol,n-heptane and RuCl3 · 3H2O aqueous solution to form microemulsion.The ruthenium nanoparticles were prepared by the hydrate hydrazine reducing.The demulsifier was added to the ruthenium microemulsion system,the Ru nanoparticles were loaded on the NaY to get the M-Ru/NaY catalysts.The catalysts were characterized by XRD,BET,XPS,SEM,TEM,and DSC.The results of characterization show that the M-Ru/NaY catalysts have the advantages when the average size of Ru particles is small(1 ～2 nm),uniformly and highly dispersed,comparing with the Ru/NaY catalysts prepared by microemulsion and impregnation for application in the hydrogenation of hydroquinone to 1,4-cyclohexanediol.The influence of reaction conditions on hydroge-nation activity was investigated in detail.The results show that the optimized reaction temperature is 150 ℃,hydrogen pressure is 4.0 MPa,m(M-Ru/NaY) ∶ m(hydroquinone)=0.2∶1 and the solvent is isopropyl alcohpl.Under the optimal conditions,the reaction was carried out 30 min,the M-Ru/NaY catalysts exhibited high activity.The conversion of hydroquinone was 100％ and the selectivity of 1,4-cyclohexanediol was up to 92.6％.In addition,the M-Ru/NaY catalyst has good stability.Finally,the reaction pathways were also analyzed preliminarily.