Fourier transform infrared (FTIR) spectroscopy is frequently used to characterize properties of catalytic sites, identify reaction intermediates, and probe interactions between adsorbates and surfaces, making it a versatile tool for elucidating reaction mechanisms in heterogeneous catalysis. While this technique is typically regarded as qualitative or semiquantitative in nature, quantitative results can be obtained by determining integrated molar extinction coefficients (IMECs), or the amount of signal per mole of adsorbed or bulk species. IMECs for vibrational modes corresponding to pyridine adsorbed onto Brønsted and Lewis acid sites have been determined in the vapor phase; however, the effect of solvents on catalytic sites cannot be captured. Liquid-phase IMECs enable quantification of adsorbates in the presence of solvents, allowing quantitative evaluations of the effect of solvents on catalysts. A method is outlined for determining IMECs of pyridine adsorbed on zeolites in the liquid phase in an attenuated total reflection (ATR) configuration. The method can also be applied to substrates other than pyridine. The IMECs for pyridine adsorbed onto Brønsted and Lewis acid sites in water, acetonitrile, and ethanol are determined. The IMEC values are shown to be dependent on solvent choice, but independent of zeolite framework.

傅里叶变换红外（FTIR）光谱通常用于表征催化位点的特性，识别反应中间体以及探测被吸附物与表面之间的相互作用，使其成为阐明多相催化反应机理的通用工具。虽然该技术本质上通常被视为定性或半定量的，但可以通过确定积分摩尔消光系数（IMEC）或每摩尔吸附或散装物质的信号量来获得定量结果。已经在汽相中确定了与吸附在布朗斯台德和路易斯酸位上的吡啶对应的振动模式的IMEC。但是，不能捕获溶剂对催化位点的影响。液相IMEC可在存在溶剂的情况下对吸附物进行定量，可以定量评估溶剂对催化剂的影响。概述了确定衰减全反射（ATR）配置中液相吸附在沸石上的吡啶的IMEC的方法。该方法也可以应用于除吡啶以外的其他底物。确定吡啶在水中，乙腈和乙醇中吸附到布朗斯台德和路易斯酸位上的IMEC。已显示出IMEC值取决于溶剂的选择，但与沸石骨架无关。确定乙腈和乙醇。已显示出IMEC值取决于溶剂的选择，但与沸石骨架无关。确定乙腈和乙醇。已显示出IMEC值取决于溶剂的选择，但与沸石骨架无关。