Researcher
Evan Curtin

Objective

To determine the solubility of benzalaniline from Exp261 in ethanol, hexane, toluene, by NMR method.

Procedure

Make saturated solutions of the solute in the solvents of interest. Do this by mixing the solute into the solvent. Heat to around 40-45C. If all solid dissolved, let sit on counter, but if there is still solid remaining, decant immediately into a clean container and let the supernatant sit on counter. Let solution stand to equilibriate. If the solid precipitates, decant the supernatant. This is a saturated solution. However, if there is no solid, try to precipitate solid using a sonicator. If there is still no precipitate, evaporate solvent slowly using air, sonicating from time to time to avoid supersaturation (be careful that the temperature doesn't drop too low). Once solid precipitates, decant the solution. This is saturated.

Take some saturated solution (100-300 microliters). Add deuterated solvent to the solution (a few hundred microliters). Add the new solution to an NMR tube so that the solution fills 5cm in the tube. Take the HNMR spectrum of the solution. Use webservice to compare the solute and solvent peaks.

Results

Mass of solute and solvents

Discussion

The total mass of benzalaniline used (sample 2D from UCExp261) was 1.0954g. The reported yield in that experiment was 2.3956g. The characterization of sample 2D could be erroneous.
Solubility information can be determined for unsaturated solutions for each solvent. Since the values in this experiment were for unsaturated solutions, the solubility of benzalaniline is greater than the values listed below for each solvent.
Ethanol: 1.40 M
n-hexane: 0.65 M
toluene: 1.31 M
benzene: 2.88 M
carbon tetrachloride: 3.21 M

Conclusion

No saturated solution was made.

Log

2011-03-18

12:29 - Weighed solute in vials. Added solvent, then weighed again. Solute in all solvents dissolved at room temperature. Not enough solute to add more to each sample.