摘要
以PdCl_(2)和钛酸正丁酯为原料、聚乙烯吡咯烷酮为金属保护剂、三嵌段共聚物EO_(96)PO_(70)EO_(96)为模板剂,采用溶胶-凝胶法制备了一系列不同Pd负载量(质量分数0.1%~1.0%)的非均相Pd/m-TiO_(2)催化剂。采用N_(2)吸附-脱附等温线、XRD和TEM对其进行了表征。结果表明,催化剂具有有序介孔结构,孔径在8.7~10.2nm之间,Pd粒子均匀分布在载体上,粒子尺寸为11.3~13.3nm。在微填充床反应器中进行了连续流Pd/m-TiO_(2)催化溴苯与苯硼酸的Suzuki偶联反应,确定了最优工艺条件:N,N-二甲基甲酰胺(DMF)和水[V(DMF)∶V(H_(2)O)=1∶1]为溶剂,碱为K_(3)PO_(4),流速为0.20 mL/min,溴苯、苯硼酸和K_(3)PO_(4)的浓度分别为0.10、0.12和0.15 mol/L,Pd负载量为0.7%(质量分数)的m-TiO_(2)(记为0.7%Pd/m-TiO_(2))为催化剂,反应温度为80℃,反应时间6.8 min。在最优反应条件下考察了不同取代芳烃的Suzuki偶联反应,反应收率均达到了99%,0.7%Pd/m-TiO_(2)使用5次后仍保持良好的催化活性。
A series of heterogeneous Pd/m-TiO_(2) catalysts with different palladium loading amounts(mass fraction 0.1%~1.0%)were prepared by sol-gel method using PdCl_(2) and n-butyl titanate as raw materials,polyvinylpyrrolidone as metal protective agent,triblock copolymer EO_(96)PO_(70)EO_(96) as template agent.The structure was characterized by N_(2) adsorption-desorption isotherm,XRD and TEM.The results showed that the catalysts had an ordered mesoporous structure with 8.7~10.2 nm pore size distribution and good palladium dispersion with 11.3~13.3 nm particle size.Then Pd/m-TiO_(2) catalysts were fixed by micro-packed reactor to catalyze Suzuki coupling reaction of bromobenzene and phenylboric acid in continuous flow.The optimal continuous flow process was determined:mixed solvent of DMF and water[V(DMF)∶V(H_(2)O)=1∶1],K_(3)PO_(4) as alkali,flow rate of 0.20 mL/min,bromobenzene concentration of 0.10 mol/L,phenylboronic acid concentration of 0.12 mol/L,K_(3)PO_(4) concentration of 0.15 mol/L,m-TiO_(2) with palladium loading amount of 0.7%(mass fraction)(noted as 0.7% Pd/m-TiO_(2))as catalyst,reaction temperature of 80℃ and reaction time of 6.8 min.The Suzuki coupling reaction of different substituted aromatic hydrocarbons was investigated under the optimal reaction conditions.The yield of Suzuki coupling reaction was up to 99%,and 0.7% Pd/m-TiO_(2) still maintained good catalytic activity after using 5 times.
作者
薄晓帆
万力
辛忠
BO Xiaofan;WAN Li;XIN Zhong(Shanghai Key Laboratory of Multiphase Materials Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;State Key Laboratory of Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)
出处
《精细化工》
EI
CAS
CSCD
北大核心
2021年第8期1613-1620,共8页
Fine Chemicals
基金
中央高校基本科研专项资金(JKA01211721)
上海市领军人才(2013)。
