Researcher

Evan Curtin

Objective

To determine the solubility of 5 imines in 2,2,2-trifluoroethanol and compare to Abraham solubility model predictions.

Procedure

Results

SAMS spreadsheet
The solubility of each imine in 2,2,2-trifluoroethanol is:
Benzalaniline: 3.657 M
N-vanillylideneaniline: 0.072 M
salicylideneaniline: 1.502 M
N-(4-Dimethylaminobenzylidene)aniline: 2.472 M
N-(4-methoxybenzylidene)aniline: 2.754 M

Discussion

Abraham predicted solubilities for imines in 2,2,2-trifluoroethanol before the experiment were all low (much less than 1M). With the exception of the vanillin derivative, benzalaniline and substituted benzaldehyde imines were found to have relatively high solubilities in the solvent (>1M). There is clearly a large discrepancy between the predicted and experimental values. This difference is most likely a result of incorrect descriptors for trifluoroethanol, which is a result of the limited data available for trifluoroethanol solubility data. More solubility data for trifluoroethanol should increase the accuracy of the model, especially in the case of organic compounds.
All TFE solubilities are reported here .
The livet solubility predictions are available from the live Solubility Book (it will take a few minutes to load - TFE is near the end of the entire document). Predicted and measured values in TFE on 2011-10-25.

Conclusion

Solubility for 5 imines was determined in 2,2,2-trifluoroethanol was determined. Poor correlation with abraham predictions is likely due to lack of data in calculating descriptors for trifluoroethanol.

Log

2011-08-10

17:15 - Mixed 200-300mg of each imine with 100-300 microliters of trifluoroethanol in 1 dram screw cap vials.
17:29 - Heated each mixture at 50C. Samples 1, 3, 4, and 5 all dissolved in under one minute. Removed these from the bath and set on counter
17:36 - Removed sample 2 from bath, immediately filtered by pipetting the mixture through another pipette that had part of a kimwipe lodged inside.
18:10 - Precipitate formed in sample 2, blew air onto samples 1, 3, 4 and 5 slowly and sonicated each after air was blown onto it. Repeated as necessary until precipitate formed.
18:29 - Filtered each solution using pipettes with kimwipes as stated above (in each case, the precipitate floated).
18:57 - Added CDCl3 to each solution. Transferred to NMR tubes.
19:30 - Took HNMR using 500MHz varian NMR.