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Correlation between Acidity and Catalytic Performance of Mesoporous Zirconium Oxophosphate in Phenylglyoxal Conversion
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2019-03-31 00:00:00 , DOI: 10.1021/acssuschemeng.9b00989 Haimei Xu 1 , Zichun Wang 1, 2 , Zhichao Miao 3 , Yuxiang Zhu 1 , Aleksei Marianov 1 , Lizhuo Wang 2 , Patrice Castignolles 4 , Marianne Gaborieau 4, 5 , Jun Huang 2 , Yijiao Jiang 1
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2019-03-31 00:00:00 , DOI: 10.1021/acssuschemeng.9b00989 Haimei Xu 1 , Zichun Wang 1, 2 , Zhichao Miao 3 , Yuxiang Zhu 1 , Aleksei Marianov 1 , Lizhuo Wang 2 , Patrice Castignolles 4 , Marianne Gaborieau 4, 5 , Jun Huang 2 , Yijiao Jiang 1
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The one-step conversion of α-keto aldehydes to α-hydroxy carboxylic acids and their derivatives using solid acids is of great appeal in biomass utilization. In this work, ordered mesoporous zirconium oxophosphate (ZrPO) catalysts with tunable acidity were prepared and their catalytic performance was evaluated using phenylglyoxal (PG) conversion to ethyl mandelate (EM). The roles of Lewis acid sites (LAS) and Brønsted acid sites (BAS) of ZrPO were investigated by kinetic studies of PG conversion combined with temperature-programmed desorption of ammonia (NH3-TPD) and solid-state NMR characterizations. It is found that the ratio of LAS to BAS on the ZrPO plays a dominant role in this reaction. ZrPO-0.75-500, with a LAS/BAS ratio of 2.1, was found to be the best catalyst. The reaction pathways, i.e., the direct isomerization of PG to EM by LAS and via the formation of an intermediate hemiacetal by BAS, are therefore proposed. Moreover, the effect of water on the catalytic activity was studied. A moderate amount of water induced either by catalyst pretreatment at the proper temperature or deliberately dosed on the ZrPO materials achieves a maximum catalytic activity. The highest catalytic activity, i.e., 82% of PG conversion and 92% of EM selectivity, was obtained on ZrPO-0.75-500 that was dosed by 15 μmol water per 50 mg of the catalyst. It is concluded that ZrPO with a suitable combination of LAS and BAS is required to efficiently and selectively catalyze the conversion of α-keto aldehydes to α-hydroxy carboxylic acid derivatives. It is feasible, from a practical point of view, to tune the density of LAS and BAS on the catalysts to achieve a better catalytic performance.
中文翻译：
苯甲酸乙二醛转化过程中介孔磷酸氧锆酸度与催化性能的相关性
使用固体酸将α-酮醛一步转化为α-羟基羧酸及其衍生物在生物质利用中具有极大的吸引力。在这项工作中，制备了具有可调酸度的有序介孔过氧磷酸锆（ZrPO）催化剂，并使用苯基乙二醛（PG）转化为扁桃酸乙酯（EM）评估了它们的催化性能。通过PG转化的动力学研究以及程序升温的氨（NH 3）脱附的动力学研究，研究了ZrPO的路易斯酸位（LAS）和布朗斯台德酸位（BAS）的作用。-TPD）和固态NMR表征。发现在ZrPO上LAS与BAS的比例在该反应中起主要作用。LAS / BAS比为2.1的ZrPO-0.75-500被认为是最好的催化剂。因此提出了反应途径，即通过LAS将PG直接异构化成EM，以及通过BAS形成中间体半缩醛。此外，研究了水对催化活性的影响。通过在适当的温度下通过催化剂预处理或故意添加到ZrPO材料上适量的水可获得最大的催化活性。在ZrPO-0.75-500上获得最高的催化活性，即PG转化率为82％，EM选择性为92％，每50 mg催化剂按15μmol水投加。结论是需要ZrPO与LAS和BAS的适当组合才能有效和选择性地催化α-酮醛向α-羟基羧酸衍生物的转化。从实践的角度来看，调整催化剂上LAS和BAS的密度以获得更好的催化性能是可行的。
更新日期：2019-03-31
中文翻译：
苯甲酸乙二醛转化过程中介孔磷酸氧锆酸度与催化性能的相关性
使用固体酸将α-酮醛一步转化为α-羟基羧酸及其衍生物在生物质利用中具有极大的吸引力。在这项工作中，制备了具有可调酸度的有序介孔过氧磷酸锆（ZrPO）催化剂，并使用苯基乙二醛（PG）转化为扁桃酸乙酯（EM）评估了它们的催化性能。通过PG转化的动力学研究以及程序升温的氨（NH 3）脱附的动力学研究，研究了ZrPO的路易斯酸位（LAS）和布朗斯台德酸位（BAS）的作用。-TPD）和固态NMR表征。发现在ZrPO上LAS与BAS的比例在该反应中起主要作用。LAS / BAS比为2.1的ZrPO-0.75-500被认为是最好的催化剂。因此提出了反应途径，即通过LAS将PG直接异构化成EM，以及通过BAS形成中间体半缩醛。此外，研究了水对催化活性的影响。通过在适当的温度下通过催化剂预处理或故意添加到ZrPO材料上适量的水可获得最大的催化活性。在ZrPO-0.75-500上获得最高的催化活性，即PG转化率为82％，EM选择性为92％，每50 mg催化剂按15μmol水投加。结论是需要ZrPO与LAS和BAS的适当组合才能有效和选择性地催化α-酮醛向α-羟基羧酸衍生物的转化。从实践的角度来看，调整催化剂上LAS和BAS的密度以获得更好的催化性能是可行的。
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