Homogeneous Catalytic Processes Monitored by Combined in Situ ATR-IR, UV–Vis, and Raman Spectroscopy

Abstract

The benefit of coupling in situ spectroscopic methods (attentuated total reflectance-infrared spectroscopy (ATR-IR), Raman, and UV−vis) for the real-time monitoring of homogeneously catalyzed reactions is exemplarily demonstrated on selected examples of use. In this context, the different mode of catalyst action in reduction reactions of imides and amides with phenylsilanes will be discussed. In the iron-catalyzed decomposition of formic acid, different intermediate iron complexes were identified and the inhibiting effect of chloride onto active iron complex formation could be elucidated. Furthermore, it could be shown that in a Lewis acid catalyzed cyclocondensation reaction, the reactant activation proceeds differently with AlCl 3 and TiCl 4 . For the described in situ spectroscopic studies, a versatile setup was used which allows the simultaneous registration of ATR-IR, UV−vis, and Raman spectra in small volumes of solution at different reaction-determined conditions using fiber-optic probes for the each spectroscopy.

Highly Efficient and Convenient Supported Ionic Liquid TiCl5-DMIL@SiO2@Fe3O4-Catalyzed Cycloaddition of CO2 and Epoxides to Cyclic Carbonates

“…In addition to this peak, another peaks appeared at around 413, 492, 556 nm in Fig. 5f, which is likely to be associated with the characteristic absorption band of Ti-Cl [47][48][49].…”

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

“…In such cases, the characterization with IR‐ATR spectroscopy opened a wide range of possibilities for in situ studies of liquid‐solid adsorption . Experimental setups concerning IR‐ATR continuous flow, batch cells, and others have been adapted for studying the adsorption of probe molecules in the liquid phase, as well as for homogeneous and heterogeneous catalytic processes and electrochemical studies . In particular, Rivera et al .…”

“…[26] Experimental setups concerning IR-ATR continuous flow, [27][28][29] batch cells, [30] and others have been adapted for studying the adsorption of probe molecules in the liquid phase, [26] as well as for homogeneous and heterogeneous catalytic processes and electrochemical studies. [31][32][33][34][35][36][37][38] In particular, Rivera et al performed pyridine adsorption in liquid phase over sol-gel films deposited over the ATR crystal solubilized in n-heptane and methanol. [27] Panella et al used a liquid-solid IR-ATR batch cell to study the reactivity of amino-functionalized silica-coated magnetic nanoparticles of SiO 2 /Fe 3 O 4 .…”

Mechanistic Study of In Situ Generation and Use of Methanesulfonyl Azide as a Diazo Transfer Reagent with Real‐Time Monitoring by FlowNMR

“…Many spectroscopic techniques are suitable for real‐time reaction monitoring by in situ process analysis, including ultraviolet‐visible (UV/Vis), infrared (IR), Raman and nuclear magnetic resonance (NMR) spectroscopy . These methods permit observation of a reaction system with minimal or negligible disturbance, which is particularly advantageous in determining an accurate kinetic profile.…”