Researcher

Marshall Moritz

Objective

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


Procedure

Saturated solutions of nicotinic 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 600uL of CDCl3 in the appropriate NMR tubes. An NMR of each sample was taken on the 500MHz Variac instrument.

Results


Spreadsheet Exp100

Spectra

ONSCExp100A1 Raw data for JCAMP dx file ONSCExp100A1
ONSCExp100A2 Raw data for JCAMP dx file ONSCExp100A2
ONSCExp100A3 Raw data for JCAMP dx file ONSCExp100A3
ONSCExp100M1 Raw data for JCAMP dx file ONSCExp100M1
ONSCExp100M2 Raw data for JCAMP dx file ONSCExp100M2
ONSCExp100M3 Raw data for JCAMP dx file ONSCExp100M3
ONSCExp100D1 Raw data for JCAMP dx file ONSCExp100D1
ONSCExp100D2 Raw data for JCAMP dx file ONSCExp100D2
ONSCExp100D3 Raw data for JCAMP dx file ONSCExp100D3
ONSCExp100O2 Raw data for JCAMP dx file ONSCExp100O2
ONSCExp100O3 Raw data for JCAMP dx file ONSCExp100O3
ONSCExp100T1 Raw data for JCAMP dx file ONSCExp100T1
ONSCExp100T2 Raw data for JCAMP dx file ONSCExp100T2
ONSCExp100T3 Raw data for JCAMP dx file ONSCExp100T3

Discussion

The concentration of nicotinic 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 nicotinic acid [1]; the set of values for each solvent was very uniform. The solubility of nicotinic acid in acetonitrile and toluene was zero, however the integration of some peaks in the NMR spectra yielded slightly negative concentration values even when the upper and lower limits of integration were set to zero. These values were manually changed to zero (noted as red numbers in the spreadsheet), as the concentration was assumed to be zero instead of negative; the solvents in which this problem occurred had other concentration values of zero so it was a safe assumption. Otherwise, the experiment generated good results, though this does not account for potential uniform systematic errors, and the experiment was successful.

Conclusion

The solubility of nicotinic acid in acetonitrile was found to be 0.00M, 0.00M, and 0.00M. The mean value was 0.00M and the standard deviation was 0.00.
The solubility of nicotinic acid in methanol was found to be 0.07M, 0.06M, and 0.06M. The mean value was 0.063M and the standard deviation was 0.005.
The solubility of nicotinic acid in DMSO was found to be 0.58M, 0.54M, and 0.58M. The mean value was 0.566M and the standard deviation was 0.02.
The solubility of nicotinic acid in THF was found to be 0.03M, 0.05M, and 0.05M. The mean value was 0.043M and the standard deviation was 0.011.
The solubility of nicotinic acid in toluene was found to be 0.00M, and 0.00M. The mean value was 0.00M and the standard deviation was 0.00.

Log

2009-05-27
10:19--Added 300uL of DMSO to 3 vials labeled D1, D2, and D3.
10:21--Added 300uL of acetonitrile to 3 vials labeled A1, A2, and A3.
10:24--Added 300uL of methanol to 3 vials labeled M1, M2, and M3.
10:26--Added 300uL of THF to 3 vials labeled T1, T2, and T3.
10:29--Added 300uL of toluene to 3 vials labeled O1, O2, and O3.
10:36--After adding 2 small scoops of nicotinic acid to vials D1, D2, and D3, the vials were capped and vortexed for approximately 10 seconds. This was repeated three times and the solution was found to be saturated.
10:39--After adding 2 small scoops of nicotinic acid to vials T1, T2, and T3, the vials were capped and vortexed for approximately 10 seconds. This was repeated twice and the solution was found to be saturated.
10:43--After adding 2 small scoops of nicotinic acid to vials M1, M2, and M3, the vials were capped and vortexed for approximately 10 seconds. This was repeated three times and the solution was found to be saturated.
10:46--After adding 2 small scoops of nicotinic acid to vials O1, O2, and O3, the vials were capped and vortexed for approximately 10 seconds. This was repeated three times and the solution was found to be saturated.
10:50--After adding 2 small scoops of nicotinic acid to vials A1, A2, and A3, the vials were capped and vortexed for approximately 10 seconds. This was repeated twice and the solution was found to be saturated.
11:02--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.
11:34--All vials were removed from the sonicator and set out to cool to room temperature.
11:44--All vials were found to be saturated
11:45--The saturated solutions from all vials, A1, A2, A3, O1, O2, O3, T1, T2, T3, D1, D2, D3, M1, M2, and M3 were carefully collected by pasteur pipette; the supernatant was cleanly separated from the precipitate and thus easily removed.
12:03--NMR tubes were prepared for all vials; the saturated solutions collected from each vial were added to 600uL of CDCl3 in appropriately labelled NMR tubes.
12:15--Tubes D1, D2, D3 showed precipitate. Set aside tubes, made new ones. After ten minutes, D1, D2, D3 again showed precipitate.
13:00--NMR of al vials was taken on the 300MHz machine.

References

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

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