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Reactant Additive-Triggered Deactivation of Pd/γ-Alumina-Catalyzed Hydrogenation Reactions. A Reactivity and Adsorption Study
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2020-09-08 , DOI: 10.1021/acs.iecr.0c03238 Peng Du 1 , Ignacio Melián-Cabrera 1, 2 , Bart van der Linden 1, 3 , Harrie Jansma 1, 3 , Jacob A. Moulijn 1, 3
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2020-09-08 , DOI: 10.1021/acs.iecr.0c03238 Peng Du 1 , Ignacio Melián-Cabrera 1, 2 , Bart van der Linden 1, 3 , Harrie Jansma 1, 3 , Jacob A. Moulijn 1, 3
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Deactivation of a Pd/alumina catalyst has been observed during the hydrogenation of α-methylstyrene and styrene. In both feedstocks, deactivation is caused by an additive, 4-tert-butylcatechol (TBC), a polymerization inhibitor, commonly employed at the ppm concentration level in the formulation of commercial monomers. It was found that the reaction rate in the α-methylstyrene fluctuated notably among the reactant vendors, and this was ascribed to the varying concentration of TBC, although other factors, such as the concentration of water, may play a role. The study was extended into the hydrogenation of styrene using a trickle bed reactor. The negative impact of the TBC present at the ppm level was obvious. The deactivation mechanism was complex to rationalize. A two-stage behavior was observed: a first stage of a relatively fast deactivation followed by a second stage of slow deactivation. A tentative explanation considers the presence of two types of Pd-sites, which are poisoned by TBC: the more active α-Pd–H sites and the less active β-Pd–H sites. Finally, in practical terms, it is important to emphasize that such an additive must be removed from the reactant to maximize the catalyst performance. This can be achieved by adsorption using a commercial F-200 Alcoa alumina.
中文翻译：
Pd /γ-氧化铝催化的加氢反应的反应物添加剂触发的失活。反应性和吸附研究
在α-甲基苯乙烯和苯乙烯的氢化过程中，观察到了Pd /氧化铝催化剂的失活。在这两种原料中，失活都是由4-叔叔添加剂引起的。-丁基邻苯二酚（TBC），一种阻聚剂，通常在商业单体配方中以ppm浓度使用。发现在α-甲基苯乙烯中的反应速率在反应物供应商之间显着波动，这归因于TBC的浓度变化，尽管诸如水的浓度的其他因素可能起作用。该研究扩展到使用滴流床反应器对苯乙烯进行氢化。ppm水平存在的TBC的负面影响是显而易见的。停用机制难以合理化。观察到了两个阶段的行为：相对快速停用的第一阶段，然后是缓慢停用的第二阶段。暂定解释考虑了两种类型的Pd位点的存在，它们被TBC毒化：活性较高的α-Pd–H位点和活性较低的β-Pd–H位点。最后，实际上，重要的是强调必须从反应物中除去这种添加剂以使催化剂性能最大化。这可以通过使用市售的F-200 Alcoa氧化铝进行吸附来实现。
更新日期：2020-10-07
中文翻译：
Pd /γ-氧化铝催化的加氢反应的反应物添加剂触发的失活。反应性和吸附研究
在α-甲基苯乙烯和苯乙烯的氢化过程中，观察到了Pd /氧化铝催化剂的失活。在这两种原料中，失活都是由4-叔叔添加剂引起的。-丁基邻苯二酚（TBC），一种阻聚剂，通常在商业单体配方中以ppm浓度使用。发现在α-甲基苯乙烯中的反应速率在反应物供应商之间显着波动，这归因于TBC的浓度变化，尽管诸如水的浓度的其他因素可能起作用。该研究扩展到使用滴流床反应器对苯乙烯进行氢化。ppm水平存在的TBC的负面影响是显而易见的。停用机制难以合理化。观察到了两个阶段的行为：相对快速停用的第一阶段，然后是缓慢停用的第二阶段。暂定解释考虑了两种类型的Pd位点的存在，它们被TBC毒化：活性较高的α-Pd–H位点和活性较低的β-Pd–H位点。最后，实际上，重要的是强调必须从反应物中除去这种添加剂以使催化剂性能最大化。这可以通过使用市售的F-200 Alcoa氧化铝进行吸附来实现。
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