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Synthesis of Pd/SiO2 Catalysts in Various HCl Concentrations for Selective NBR Hydrogenation: Effects of H+ and Cl– Concentrations and Electrostatic Interactions
ACS Omega ( IF 3.7 ) Pub Date : 2018-06-20 00:00:00 , DOI: 10.1021/acsomega.8b00244 Tingting Cheng 1 , Jian Chen 1 , Aofei Cai 1 , Jian Wang 1 , Haiyan Liu 1 , Yuandong Hu , Xiaojun Bao , Pei Yuan 2
ACS Omega ( IF 3.7 ) Pub Date : 2018-06-20 00:00:00 , DOI: 10.1021/acsomega.8b00244 Tingting Cheng 1 , Jian Chen 1 , Aofei Cai 1 , Jian Wang 1 , Haiyan Liu 1 , Yuandong Hu , Xiaojun Bao , Pei Yuan 2
Affiliation
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A series of silica supported Pd (Pd/SiO2) catalysts were prepared in various HCl concentrations (CHCl) of the impregnation solution with different electrostatic interactions between Pd precursor and support, and their catalytic properties were evaluated by the selective hydrogenation of nitrile butadiene rubber (NBR). The results show that with the CHCl increasing from 0.1 to 5 M, the particle size of Pd nanoparticles dramatically decreases from 24.2 to 5.1 nm and stabilizes at ∼5 nm when CHCl is higher than 2 M. Using the catalysts prepared with a high CHCl (>2 M), an excellent hydrogenation degree (HD) of ∼94% with 100% selectivity to C═C can be acquired under mild conditions. Interestingly, the HD could be remarkably increased from 65 to 92% by increasing only CCl– from 0.1 to 2 M with the addition of NaCl while keeping CH+ at 0.1 M. This is because PdCl42– is the predominant existing form of precursor at high CCl–, which has a strong electrostatic attraction with the positively charged support favorable for the formation of small-sized Pd nanoparticles over silica. Notably, Pd leaching behavior during the hydrogenation reaction is closely related to CH+, and the higher the CH+, the less Pd residues are detected in the hydrogenated NBR. Our contribution is to provide a facile strategy to synthesize effective and stable Pd/SiO2 catalysts via adjusting the electrostatic interaction, which exhibits a high activity and selectivity for NBR hydrogenation.
中文翻译：
的Pd /二氧化硅的合成2种催化剂在各种盐酸浓度为选择性加氢NBR：H的影响+和Cl -浓度和静电相互作用
制备了一系列在不同HCl浓度（C HCl）下浸渍的Pd（Pd / SiO 2）二氧化硅载体，Pd前驱体与载体之间存在不同的静电相互作用，并通过腈丁二烯的选择性加氢反应评价了它们的催化性能。橡胶（NBR）。结果表明，随着C HCl从0.1 M增加到5 M，当C HCl高于2 M时，Pd纳米粒子的粒径从24.2 nm急剧减小到5.1 nm，并稳定在〜5 nm 。ç盐酸（> 2 M），可以在温和的条件下获得〜94％的优异氢化度（HD），对C═C的选择性为100％。有趣的是，HD可以被显着地从65通过增加仅增加至92％Ç氯-同时保持从0.1至2M与加入NaCl Ç ħ + 0.1 M.这是因为的PdCl 4 2-为主要的现有形式在高C Cl –下的前驱体具有很强的静电吸引力，带正电荷的载体有利于在二氧化硅上形成小尺寸的Pd纳米粒子。值得注意的是，加氢反应过程中Pd的浸出行为与C H +密切相关。C H +越高，氢化NBR中检测到的Pd残留量越少。我们的贡献是提供一种通过调节静电相互作用来合成有效且稳定的Pd / SiO 2催化剂的简便策略，该方法对NBR的氢化反应具有很高的活性和选择性。
更新日期：2018-06-20
中文翻译：
的Pd /二氧化硅的合成2种催化剂在各种盐酸浓度为选择性加氢NBR：H的影响+和Cl -浓度和静电相互作用
制备了一系列在不同HCl浓度（C HCl）下浸渍的Pd（Pd / SiO 2）二氧化硅载体，Pd前驱体与载体之间存在不同的静电相互作用，并通过腈丁二烯的选择性加氢反应评价了它们的催化性能。橡胶（NBR）。结果表明，随着C HCl从0.1 M增加到5 M，当C HCl高于2 M时，Pd纳米粒子的粒径从24.2 nm急剧减小到5.1 nm，并稳定在〜5 nm 。ç盐酸（> 2 M），可以在温和的条件下获得〜94％的优异氢化度（HD），对C═C的选择性为100％。有趣的是，HD可以被显着地从65通过增加仅增加至92％Ç氯-同时保持从0.1至2M与加入NaCl Ç ħ + 0.1 M.这是因为的PdCl 4 2-为主要的现有形式在高C Cl –下的前驱体具有很强的静电吸引力，带正电荷的载体有利于在二氧化硅上形成小尺寸的Pd纳米粒子。值得注意的是，加氢反应过程中Pd的浸出行为与C H +密切相关。C H +越高，氢化NBR中检测到的Pd残留量越少。我们的贡献是提供一种通过调节静电相互作用来合成有效且稳定的Pd / SiO 2催化剂的简便策略，该方法对NBR的氢化反应具有很高的活性和选择性。
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