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Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy

机译：用FTIR和15N MAS谱谱法定量纳米透镜羟基氟化镁氟化物的酸性位点

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摘要

Lewis and Br?nsted sites were quantified in a series of weak acidic hydroxylated magnesium fluorides by Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance spectroscopy (NMR) with pyridine as probe molecule. Molar extinction coefficients, which are necessary for quantitative FTIR measurements, were calculated by an easy approach. It utilizes the fact that both signals, used for the quantification by FTIR, are caused by the same deformation vibration mode of pyridine. Comparison of quantitative FTIR experiments and quantification by NMR shows that concentrations of acidic sites determined by FTIR spectroscopy have to be interpreted with caution. Furthermore, it is shown that the transfer of molar extinction coefficients from one catalyst to another may lead to wrong results. Molar extinction coefficients and concentrations of acidic sites determined by FTIR spectroscopy are affected by grinding and probably the particle size of the sample. High temperature during FTIR experiments has further impact on the quantification results.
机译：通过傅里叶变换红外光谱（FTIR）和固态核磁共振光谱（NMR）在一系列弱酸性羟基化镁氟化物中量化Lewis和Brβ的网站，用吡啶作为探针分子。通过简单的方法计算定量FTIR测量所需的摩尔消光系数。它利用了用于通过FTIR定量的两个信号是由吡啶的相同变形振动模式引起的。通过NMR的定量FTIR实验和定量的比较表明，通过FTIR光谱法测定的酸性位点必须谨慎地解释。此外，表明从一个催化剂到另一个催化剂的摩尔消光系数转移可能导致错误的结果。通过FTIR光谱法测定的摩尔消光系数和酸性位点的浓度受到研磨和样品的粒度的影响。在FTIR实验期间的高温对定量结果进一步影响。

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