S-33 AND O-17 NMR-STUDIES OF SULFOLANE IN ACETIC-ACID AND RELATED SOLVENTS

Sulphur‐33 NMR spectra were obtained for sulpholane in acetic acid, trifluoroacetic acid, methyl acetate and methyl trifluoroacetate over the entire solution range and at a variety of temperatures. Oxygen‐17 NMR spectra were recorded for both components of each solution. The line width and chemical shift data are discussed in terms of molecular interactions and viscosity variations. Some variable‐temperature measurements are included, as are some values of 13C spin‐lattice relaxation times. It is concluded that there is an interaction, probably protonation, between sulpholane and trifluoroacetic acid, although occurring to only a small extent, which is not shown by the other solutions. The 33S and 17O line widths of sulpholane are peculiarly sensitive to the interaction. Copyright © 1990 John Wiley & Sons, Ltd.