摘要
研究了Pd/C催化Suzuki反应合成2,4′,6-三氯联苯。空气氛围下Pd/C催化Suzuki偶联,大多是室温到80℃范围即可高效反应,已有大量成功实施案例。然而本文研究发现,Pd/C催化2,4′,6-三氯联苯合成,室温(21℃)下反应2 h后,检测结果显示无产物生成;反应温度为80℃反应2 h后,目标产物收率仅有5.3%,延长反应时间至4 h,目标产物也仅提高到8.7%,反应体系存在大量的原料。反应温度为80℃反应16 h后,目标产物收率下降为7.1%。作为对比,平行进行了Pd(PPh_3)_4催化合成目标产物的实验,加热至80℃过夜反应,目标产物收率达到80%。造成这种结果的可能原因在于反应底物1,3-二氯溴苯的位阻太大,Pd/C催化体系相对催化能力较弱。对于大位阻的取代溴苯底物,仍需要传统的Suzuki反应条件。
In this paper,Pd/C catalyzed Suzuki reaction to synthesize 2,4′,6-trichlorobiphenyl was reported.Most of the Pd/C-catalyzed Suzuki couplings in the air atmosphere can be efficiently reacted in the range of room temperature to 80℃,and there have been a large number of successful implementation cases.However,this study found some different results for Pd/C catalyzed synthesis of 2,4′,6-trichlorobiphenyl.After 2 hours of reaction at room temperature(21℃),the detection results showed that no product was formed;after the reaction temperature was maintained at 80℃for 2 hours,The yield of the target product is only 5.3%,and the reaction time is extended to 4 hours,and the target product is only increased to 8.7%,and there are a lot of raw materials in the reaction system.After the reaction temperature was 80℃for 16 hours,the yield of the target product dropped to 7.1%.As a comparison,the experiment of Pd(PPh 3)4-catalyzed synthesis of the target product was carried out in parallel in this paper,and the reaction was heated to 80℃overnight,and the yield of the target product reached 80%.The possible reason for this result is that the steric hindrance of the reaction substrate 1,3-dichlorobromobenzene is too large,and the relative catalytic ability of the Pd/C catalytic system is relatively weak.For bulky substituted bromobenzene substrates,traditional Suzuki reaction conditions are still required.
作者
贾瑶
李雨欣
李鑫
王关林
刘思雨
蒋春香
罗通
黄飞
薛智
Jia Yao;Li Yuxin;Li Xin;Wang Guanlin;Liu Siyu;Jiang Chunxiang;Luo Tong;Huang Fei;Xue Zhi(Department of International Applied Technology,Yibin University,Yibin 644000,China;Yibin Collaborative Workstation of Nobel Laureate Team Member,Yibin University,Yibin 644000,China;College of Resources&Environment,Aba Teachers University,Wenchuan 623002,China)
出处
《山东化工》
CAS
2023年第5期36-39,共4页
Shandong Chemical Industry
基金
四川省科技计划项目(2020JDRC0064)
宜宾学院省级大学生创新创业训练计划项目基金(项目编号:S201910641084,S201910641058)。
