Researcher

Matthew McBride

Objective

To determine the solubility of trans-cinnamic acid in cyclohexanone and 1,2-dichloroethane at 25C with the SAMS HNMR method

Procedure

Cinnamic acid was mixed in each of the two solvents (cyclohexanone and 1,2-dichloroethane) and placed in a 45C water bath for a few minutes to create a saturated solution. The solutions were placed at 25C to allow precipitate to form. The supernatant from each solution was isolated and prepared for analysis by HNMR. An HNMR spectra was obtained for each solution and the solubility of cinnamic acid in each solvent was determined by integrating the peaks.

Results

ONSEXP-255-1 [I fixed the spectra - use the new numbers JCB] [Numbers were updated and SolSum was updated - Matthew]
Solubility of cinnamic acid in cyclohexanone: 1.437M
Solubility of cinnamic acid in 1,2-dichloroethane: 0.362M

Discussion

Based on the Abraham Model, the predicted solubility of cinnamic acid in cyclohexanone was 1.553M. The measured solubility was 1.437M, which showed excellent agreement with the predicted value. The predicted solubility of cinnamic acid in 1,2-dichloroethane was 0.425M. The measured solubility was 0.362M, which also demonstrated excellent agreement with the predicted value. This experiment demonstrated that at 25C the Abraham Model was able to accurately predict the solubility of cinnamic acid in the organic solvents cyclohexanone and 1,2-dichloroethane. (see FigShare archived predicted and measured solubilities of cinnamic acid on 2012-02-16)
EXP255cyclohexanoneprediction.png
EXP2551,2dichloroethaneprediction.png

The density of cinnamic acid is 1.185 g/mL and the density of 1,2-dichloroethane is 1.174 g/mL. Consequently, the solubility of cinnamic acid in 1,2-dichloroethane cannot be determined through the use of the density method since the densities are so similar. This was observed in EXP251. This solubility determination needed to by made through the use of HNMR analysis as was done in this experiment.

Conclusion

The solubility of cinnamic acid in cyclohexanone at 25C is 1.437M and the solubility of cinnamic acid in 1,2-dichloroethane at 25C is 0.362C. Each of the solubility were accurately predicted by the Abraham Model. [Well done JCB]

Log

2012-01-31

14:30 Filled two 1 dram screw cap vials about 1/3 full with cinnamic acid.
14:37 Added cyclohexanone to vial #1 until the vial was about 3/4th full. Added 1,2-dichloroethane to vial #2 until the vial was about 3/4th full. The solid in vial #1 (cyclohexanone) immediately went into solution, so more cinnamic acid was added to this vial.
14:40 The vials were swirled in a 45C water bath for approximately two minutes. All of the solid dissolved into both solutions. Both viles were sonicated.
14:44 The vials were placed on the lab counter since the temperature of the lab was at exactly 25C.
14:45 Vial #1 (cyclohexanone) was sonicated and precipitate began to come out of the solution. Precipitate was visible in Vial #2 (dichloroethane). The precipitates did not appear to be settling in either solution, but floating in the middle of each solution.
14:50 Placed a small piece of kimwipe in the bottom of two glass pipettes. These will be used to filter the solutions to ensure that no precipitate enters the NMR tubes.
15:07 Pipetted the supernatant solution from vial #1 (cyclohexanone) through the pipette containing the kimwipe into glass vial #1. Pipetted the supernatant solution from vial #2 (dichloroethane) through another pipette containing kimwipe into glass vial #2.
15:14 To both vial #1 and vial #2 containing the supernatants, CDCl3 was added to create an approximately 50/50 solution in each vial.
15:15 The solution in each vial was added to two thin long glass NMR tubes. Each NMR tube was filled approximately 5cm.
15:17 Each sample was analyzed using 500MHz varian NMR.