Measuring the solubility of liquid aldehydes 3,5-dimethylbenzaldehyde and 4-ethylbenzaldehyde in ethanol, methanol and THF by miscibility and density


Method

400 µL ethanol was added to a 7.5 mL glass screw cap vial. 600 µL 3,5-dimethylbenzaldehyde was added to the ethanol and the vial vortexed for 10 seconds. Complete miscibility was obtained. The vial was vortexed for a further 50 seconds in 10 second intervals to ensure the solution was thoroughly mixed. This process was repeated for 3,5-dimethylbenzaldehyde in methanol and THF.
400 µL ethanol was added to a 7.5 mL glass screw cap vial. 600 µL 4-ethylbenzaldehyde was added to the ethanol and the vial vortexed for 10 seconds. Complete miscibility was obtained. The vial was vortexed for a further 30 seconds in 10 second intervals to ensure the solution was thoroughly mixed. The solution was not vortexed for longer as bubbles were forming and I did not wish the pressure to build too much. This process was repeated for 4-ethylbenzaldehyde in methanol and THF.

Results

The aldehydes were fully miscible in all three solvents therefore we can use the density to calculate the maximum concentration solution that can be prepared from each aldehyde. [Jenny what is your source for the density? JCB][Source of density is Sigma-Aldrich: it's what is printed on the bottle - JH]
Aldehyde
Density (g/mL)
Density (g/L)
RMM
Concentration (M)
3,5-dimethylbenzaldehyde
0.998
998
134.2
7.44
4-ethylbenzaldehyde
0.979
979
134.18
7.30