Hydrogen bonding is an intermolecular force and a significant chemical property of many polar molecules. ³¹P NMR spectroscopy was used to characterize the hydrogen-bonding properties of four alcohols: ethylene glycol, trifluoroethanol, ethanol, and isopropanol. Triethylphosphine oxide (TEPO) produces a single peak in ³¹P NMR spectra that can shift by up to 7 ppm upon the addition of alcohol H-bond donors (HBDs). The goal of this research is to use the peak shift values in ³¹P NMR experiments to quantify various alcohols’ ability to act as H-bond donors and properties such as acidity, catalytic activity, and utility for electrochemical carbon capture as an additive to quinone. The experimental procedure for TEPO measurements was straightforward and introduced analytical skills such as the use of NMR instrumentation and the maintenance of dry, inert environments throughout sample preparation. The alcohols, which were chosen for their varied structures, shared a saturation point around 10-12 molar equivalents. Out of the alcohols used for titration, trifluoroethanol produced the largest TEPO peak shift in the spectra (6.9 ppm). Future work will apply our knowledge of the saturation point to compare more alcohols using ³¹P NMR measurements of TEPO shift.

<sup>31</sup>P NMR spectra for triethylphosphine oxide upon addition of trifluoroethanol.

³¹P NMR spectra for triethylphosphine oxide upon addition of trifluoroethanol.

Saturation curves for the four alcohols studied.

James Vesto

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