Researcher

Marshall Moritz

Objective

To determine the solubility of furoic acid in 5 different solvents: methanol, acetonitrile, THF, DMSO, and toluene by NMR spectropscopy.

Procedure

Saturated solutions of furoic acid in 5 different solvents were prepared by adding excess solute to 300uL of solvent in a one-dram vial. The vials were vortexed for approximately 10 seconds and if necessary, more solute was added until after vortexing, precipitate remained on the bottom of the vial. The vials were sonicated until solid remained for 30 minutes of consecutive sonication. The supernatant was then removed from the vials by Pasteur pipette. NMR tubes were labelled appropriately; M for methanol, A for acetonitrile, T for THF, D for DMSO, and O for toluene. 2-3 drops of the supernatant were added to 500uL of CDCl3 in the appropriate NMR tubes. An NMR of each sample was taken on the 300MHz Varian instrument.

Results

Spreadsheet Exp104

Spectra

ONSCExp104A1 Raw data for JCAMP dx file ONSCExp104A1
ONSCExp104A2 Raw data for JCAMP dx file ONSCExp104A2
ONSCExp104A3 Raw data for JCAMP dx file ONSCExp104A3
ONSCExp104D1 Raw data for JCAMP dx file ONSCExp104D1
ONSCExp104D2 Raw data for JCAMP dx file ONSCExp104D2
ONSCExp104D3 Raw data for JCAMP dx file ONSCExp104D3
ONSCExp104M1 Raw data for JCAMP dx file ONSCExp104M1
ONSCExp104M2 Raw data for JCAMP dx file ONSCExp104M2
ONSCExp104M3 Raw data for JCAMP dx file ONSCExp104M3
ONSCExp104O1 Raw data for JCAMP dx file ONSCExp104O1
ONSCExp104O2 Raw data for JCAMP dx file ONSCExp104O2
ONSCExp104O3 Raw data for JCAMP dx file ONSCExp104O3
ONSCExp104T1 Raw data for JCAMP dx file ONSCExp104T1
ONSCExp104T2 Raw data for JCAMP dx file ONSCExp104T2
ONSCExp104T3 Raw data for JCAMP dx file ONSCExp104T3

Discussion

The concentration of furoic acid in any non-aqueous solvent had not been previously reported at the time of this experiment. Thus the values generated by this experiment could not be compared to any other values but themselves. There were no statistical anomalies in the solubility of furoic acid [1], however the data set for each solvent was not convincingly uniform. The solubility of furoic acid in DMSO and THF both had standard deviations greater than 0.30, which is slightly concerning. It would be helpful to repeat these experiments to add more values to the data sets to lower the standard deviation and close in on a solubility value. Also, several of the NMR tubes appeared cloudy after adding the supernatants to the CDCl3. It is probable that the supernatants were supersaturated; though they had 30 minutes to cool and there was solid on the bottom of the vial, the precipitate and the vial may not have provided ample surfaces to induce crystallization. Seeding each vial to ensure the solutions are saturated and not supersaturated would be a good idea for future experimentation. However, the appearance of solid in the NMR tubes did not greatly affect the spectra, though it could account for the higher standard deviations in a few of the solvents. Other than these notable remarks, the experiment generated good results. Though this does not account for potential uniform systematic errors, the experiment was successful.

Conclusion

The solubility of furoic acid in acetonitrile was found to be 1.08M, 1.15M, and 1.06M. The mean value was 1.096M and the standard deviation was 0.047.
The solubility of furoic acid in methanol was found to be 4.36M, 3.96M, and 4.05M. The mean value was 4.123M and the standard deviation was 0.209.
The solubility of furoic acid in DMSO was found to be 6.40M, 6.53M, and 6.99M. The mean value was 6.64M and the standard deviation was 0.31.
The solubility of furoic acid in toluene was found to be 0.06M, 0.06M, and 0.06M. The mean value was 0.06M and the standard deviation was 0.00.
The solubility of furoic acid in THF was found to be 3.72M, 4.13M, and 4.36M. The mean value was 4.07M and the standard deviation was 0.32.

Log

2009-06-01
9:54--Added 300uL of DMSO to 3 vials labeled D1, D2, and D3.
9:57--Added 300uL of THF to 3 vials labeled T1, T2, and T3.
10:00--Added 300uL of methanol to 3 vials labeled M1, M2, and M3.
10:03--Added 300uL of acetonitrile to 3 vials labeled A1, A2, and A3.
10:05--Added 300uL of toluene to 3 vials labeled O1, O2, and O3.
10:07--After adding 5 small scoops of furoic acid to vials D1, D2, and D3, the vials were capped and vortexed for approximately 10 seconds. This was repeated two times and the solution was found to be saturated.
10:14--After adding 2 small scoops of furoic acid to vials T1, T2, and T3, the vials were capped and vortexed for approximately 10 seconds. This was repeated once and the solution was found to be saturated.
10:19--After adding 3 small scoops of furoic acid to vials M1, M2, and M3, the vials were capped and vortexed for approximately 10 seconds. This was repeated once and the solution was found to be saturated.
10:21--After adding 1 small scoop of furoic acid to vials O1, O2, and O3, the vials were capped and vortexed for approximately 10 seconds. This was repeated once and the solution was found to be saturated.
10:24--After adding 2 small scoops of furoic acid to vials A1, A2, and A3, the vials were capped and vortexed for approximately 10 seconds. This was repeated once and the solution was found to be saturated.
11:31--All vials A1, A2, A3, O1, O2, O3, T1, T2, T3, D1, D2, D3, M1, M2, and M3 were set in a large beaker filled one-quarter with water and placed in the sonicator. The temperature was read at 20.5C and the timer was set to 30 minutes.
11:05--All vials were removed from the sonicator and set out to cool to room temperature.
11:44--All vials were found to be saturated

2009-06-02
9:33--The supernatants from vials A1, A2, A3, M1, M2, M3, T1, T2, and T3 were collected by pasteur pipette and placed in appropriately labelled NMR tubes.
9:47--The superntants from vials O1, O2, O3, D1, D2, and D3 were collected by filtration and placed in appropriately labelled NMR tubes.; the solutions were passed through pasteur pipettes packed with cotton, trapping any solid and letting only the saturated solutions pass through.
10:03--500uL was added to all NMR tubes with the saturated solutions.

2009-06-03
10:00--The NMR spectra of all vials were taken on the 300MHz Varian instrument.

References

[1] Solubility of furoic acid in non-aqueous solvents

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