Researcher

Evan Curtin

Objective

To determine the solubility of benzalaniline (from UCexp263) in ethanol, toluene, acetonitrile, chloroform and THF via the SAMS NMR method.

Procedure

Mixtures of each solvent and benzalaniline were heated in a 53C bath until a clear solution was formed. The samples were then allowed to cool at RT for 27 minutes. Air was blown onto samples until precipitate formed if necessary. The samples were allowed to sit at RT overnight. An HNMR was taken for each supernatant with CDCl3 as the solvent.

Results

Solubility measurements for benzalaniline and molar percent imine in solution:
ethanol: 1.24 M, 4.47%
toluene: 3.51 M, 3.68%
acetonitrile: 3.656 M, 2.79%
chloroform: See discussion
THF: 4.037 M, 3.10%

SAMS Spreadsheet

Sample 1: CDCl3 used as deuterated solvent


Sample 2: CDCl3 used as deuterated solvent


Sample 3: CDCl3 used as deuterated solvent


Sample 4: CDCl3 used as deuterated solvent


Sample 5: CDCl3 used as deuterated solvent


Discussion

1) Formation of the aldehyde was observed in all five samples. The percent of aldehyde formed ranged from 1.68% of the imine in sample 4 to 11.89% of the imine in sample 5. There was no perceptible aldehyde in the source of the benzalaniline (UCexp263)(HNMR). In each case, the imine appeared to have hydrolyzed in solution. The lack of water however, indicates that this can't be the case. A heterogeneous mixture of benzalaniline, however, would explain the aldehyde's presence without water.
2) The chloroform peak overlaps with some of the aromatic peaks present in benzalaniline. Because of this, the chloroform peak could not be integrated accurately and no measurement for solubility could be made.

Conclusion

The solubility of benzalaniline is 1.24M in ethanol, 3.56M in toluene, 3.70M in acetonitrile and 4.091M in THF. Solubility in chloroform was not determined, and in each case the sample hydrolyzed to some extent.

Log

2011-05-18

13:56 - Added benzalaniline to each solvent. Sonicated for 5 seconds. If the solid dissolved, added more to the solution. Repeated until all samples had some solid remaining after sonication.
13:58 - Added to hot water bath (53C)
14:01 - All solid dissolved in all samples, set on counter at RT. (22C)
14:28 - Used air to evaporate some of each solid until precipitate formed. Let samples sit, with caps on.

2011-05-20

9:12 - Observed samples. Samples 1 and 4 have precipitate and clear solution layers. Sample 3 is clear. Samples 2 and 5 made a gel.
9:15 - Used air to evaporate solvent in sample 3 until solid precipitated. Set on counter with cap on.
11:23 - Took samples of each solution (100-300 microliters), added CDCl3. Used a spatula to stir the gels in order to obtain the supernatant where necessary. Put mixtures for each sample in an NMR tube.
11:35 - Took HNMR spectra using 500MHz variann NMR.