Exp207

media type="custom" key="9032512" N-vanillylidene aniline

Researcher
Evan Curtin

Objective
To determine the solubility of UCExp262-1A ([|ChemSpider] ) in toluene, acetonitrile, THF, and chloroform via the SAMS 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 [AL: Have all your measurements been added to solsumsheet?]
The solubility for the imine is In Toluene: 0.04 M In Acetonitrile: 0.08 M SAMS spreadsheet Picture A: media type="custom" key="8938214" media type="custom" key="8938216" media type="custom" key="8938228" Note: Deuterated solvent for Chloroform sample was DMSO-d6. media type="custom" key="8938234"

Discussion
The spectrum for the solution in acetonitrile is accurate enough to use values from. The spectrum for the THF solution has very broad peaks, and cannot be used to accurately determine the solubility. The spectrum for toluene has an additional peak compared to the pure sample's HNMR, located at 3.63 ppm. The molar ratio of imine to aldehyde in UCExp262 was about 16:1. In this experiment, the ratio was significantly shifted in the aldehyde's favor. The imine most likely hydrolized in the Toluene sample.

Conclusion
The solubility of N-vanillylidene aniline from UCExp262 was determined in toluene and acetonitrile to be 0.04M and 0.08M, respectively. The solubility in Chloroform and THF was not found.

2011-03-30
13:47 - Weighed out amounts of UCExp262-1 into screw cap vials 14:01 - Added solvent to each vial: All turned yellow except for sample 1, which is clear 1: Toluene 2: Acetonitrile 3: THF 4: Chloroform 14:25 - Heated all in 50C bath, the solid completely dissolved in each within one minute. 14:26 - Cooled each solution, allowed to equilibriate. Observed the appearance of each sample.Solution (1) was cloudy. Solution (2) was cloudy, with solid precipitate at the bottom. Sample 3 had no precipitate. In sample 4, solid precipitate formed and floated on top of the solution 14:45 - Took picture A. Left vials 1, 2 and 4 with caps on in fume hood. Left sample 3 in fume hood with the cap placed on top, but not tightly secured in a fume hood.

2011-03-31
11:48 - Made new solution of UCExp262-1 in THF in a screw-cap vial. Heated in 50C bath. Solution became clear (no solid left). 11:51 - Cooled at room temperature (20C). Solution became cloudy after sonication. Left, with a cap on, in fume hood. 16:15 - Prepared each solution in NMR tubes. 16:25 - Took HNMR spectra using 500 MHz varian NMR.