SFCNMR and Sfenmr Coupling

A separation technique employing nonprotonated solvents is SFC, using CO2. For SFC-NMR experiments a pressure-stable flow cell has been developed using a sapphire tube instead of glass (Figure 1B). At a temperature of 323 K and a pressure of 161 bar, high resolution continuous-flow NMR spectra in supercritical CO2 can be obtained.

This is demonstrated in Figure 13, showing the 1H NMR spectrum of ethylbenzene in supercritical CO2. Often, SFC-NMR separations can be performed with a pressure gradient. Thus, different isomers of vitamin A acetate are easily separated (Figure 14).

Supercritical CO2 can also be used for supercritical fluid extraction (SFE) purposes. As an example, Figure 15 shows the 1H NMR spectrum of piperin extracted from black pepper at a temperature of 370 K.

Figure 13 1H NMR spectrum (400 MHz) of ethylbenzene in supercritical CO2.

Figure 14 Contour plot (400 MHz) of the separation of vitamin A acetate stereoisomers in supercritical fluid CO2. Reprinted from Journal ofChromatography A, 761, with permission from Elsevier Science.
Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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