Objective

To determine the solubility of 4-methoxyphenylacetic acid in 5 different solvents: methanol, acetonitrile, THF, DMSO, and toluene by NMR spectropscopy.


Procedure

Saturated solutions of 4-methoxyphenylacetic acid in 5 different solvents were prepared by adding excess solute to 300uL of solvent in a half-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 for 30 minutes and if necessary, more solute was added until solid remained for 30 minutes of consecutive sonication. The supernatant was then removed from the vials either by Pasteur pipette or by filtration. 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 300MHz Variac instrument.

Results




Spreadsheet Exp089

Spectra

ONSCExp089T1 Raw Data for JCAMP dx file ONSCExpT1
ONSCExp089T2 Raw Data for JCAMP dx file ONSCExpT2
ONSCExp089T3 Raw Data for JCAMP dx file ONSCExpT3
ONSCExp089O2 Raw Data for JCAMP dx file ONSCExpO2
ONSCExp089O3 Raw Data for JCAMP dx file ONSCExpO3
ONSCExp089M1 Raw Data for JCAMP dx file ONSCExpM1
ONSCExp089M2 Raw Data for JCAMP dx file ONSCExpM2
ONSCExp089M3 Raw Data for JCAMP dx file ONSCExpM3
ONSCExp089D1 Raw Data for JCAMP dx file ONSCExpD1
ONSCExp089D2 Raw Data for JCAMP dx file ONSCExpD2
ONSCExp089D3 Raw Data for JCAMP dx file ONSCExpD3
ONSCExp089A1 Raw Data for JCAMP dx file ONSCExpA1
ONSCExp089A3 Raw Data for JCAMP dx file ONSCExpA3

Discussion

The concentration of 4-methoxyphenylacetic acid had not been previously reported at the time of experiment in any solute . Thus the values generated in this experiment could not be compared to any other values but themselves. There were no statistical anomalies in the solubilities of 4-methoxyphenylacetic acid for any solvent; the set of values for each solvent was fairly uniform [1]. Thus the experiment generated good results, though this does not account for potential uniform experimental errors. However, EXP092 has since verified the concentration of 4-methoxyphenylacetic acid in THF [2] . This experiment reported values of 3.08M, 3.20M, and 3.30M while compared to EXP092 which reported values of 3.56M, 3.37M, and 3.38M. The values are fairly close together, though vial T2, which generated a solubility of 3.08M, appears to be low in comparison to other values, thus suggesting that the solution may not have been perfectly saturated. However, the values are still relatively close and thus this experiment was successful.

Conclusion

The solubility of 4-methoxyphenylacetic acid was found in 5 different solvents. The solubility for each solvent is reported below.

The solubility of 4-methoxyphenylacetic acid in THF was found to be 3.30M, 3.08M, and 3.20M. The mean value was 3.19M and the standard deviation was 0.110.
The solubility of 4-methoxyphenylacetic acid in toluene was found to be 0.33M and 0.41M. The mean value was 0.37M and the standard deviation was 0.056.
The solubility of 4-methoxyphenylacetic acid in methanol was found to be 2.65M, 2.15M, and 2.63M. The mean value was 2.48M and the standard deviation was 0.281.
The solubility of 4-methoxyphenylacetic acid in DMSO was found to be 4.54M, 4.47M, and 4.50M. The mean value was 4.50M and the standard deviation was 0.035.
The solubility of 4-methoxyphenylacetic acid in acetonitrile was found to be 2.21M and 2.24M. The mean value was 2.225M and the standard deviation was 0.021.

Log

2009-05-13
10:28--Added 300uL of methanol to 3 vials labeled M1, M2, and M3.
10:31--Added 300uL of acetonitrile to 3 vials labeled A1, A2, and A3.
10:34--Added 300uL of THF to 3 vials labeled T1, T2, and T3.
10:37--Added 300uL of DMSO to 3 vials labeled D1, D2, and D3.
10:40--Added 300uL of toluene to 3 vials labeled O1, O2, and O3.
10:42--After adding 2 scoops of 4-methoxyphenylacetic 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.
10:48--After adding 2 scoops of 4-methoxyphenylacetic 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.
10:53--After adding 2 scoops of 4-methoxyphenylacetic acid to vials M1, M2, and M3, the vials were capped and vortexed for approximately 10 seconds. This was repeated twice and the solution was found to be saturated.
10:58--After adding 2 scoops of 4-methoxyphenylacetic acid to vials D1, D2, and D3, the vials were capped and vortexed for approximately 10 seconds. This was repeated twice and the solution was found to be saturated.
11:02--After adding 2 scoops of 4-methoxyphenylacetic acid to vials O1, O2, and O3, the vials were capped and vortexed for approximately 10 seconds. This was repeated twice and the solution was found to be saturated.
11:11--Vials A1, A2, A3, O1, O2, and O3 were set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 18.0C and the timer was set to 30 minutes.
11:46--Vials T1, T2, T3, D1, D2, D3, M1, M2, and M3 were set in the small beaker filled one-third with water and placed in the sonicator. The temperature was read at 28.0C and the timer was set to 30 minutes.
12:18--All vials were set to cool to room temperature; as the vials cooled, 4-methoxyphenylacetic acid crashed out of solution yielding saturated solutions in all vials but D1, D2, and D3.
12:34--After adding one scoop of 4-methoxyphenylacetic acid to vials D1, D2, and D3, the vials were capped and vortexed for approximately 10 seconds and the solution was again found to saturated.
12:45--Vials D1, D2, and D3 were set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 27.5C and the timer was set to 30 minutes.
13:16--After adding one scoop of 4-methoxyphenylacetic acid to vials D1, D2, and D3, the vials were capped and vortexed for approximately 10 seconds and the solution was again found to saturated.
13:25--Vials D1, D2, and D3 were set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 26.0C and the timer was set to 30 minutes.
13:58--All vials were set to cool to room temperature, yielding saturated solutions in all vials at 21.5C

2009-05-18
9:22--Vials M1 and M3 were no longer found to be saturated. After adding one scoop of 4-methoxyphenylacetic acid to vials M1 and M3, the vials were capped and vortexed for approximately 10 seconds and the solution was again found to saturated.
9:25--Vials M1 and M3 were set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 18.0C and the timer was set to 30 minutes.
9:40--Vials O1, O2, O3, and A1 yielded no supernatant, thus 40uL of the appropriate solvents were added to each vial.
9:57--Vials O1, O2, O3, and A1 were set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 26.0C and the timer was set to 30 minutes.
10:31--Vials A2, A3, O1, O2, and O3 were each filtered; the contents of the vial were passed through a pasteur pipette packed with cotton, thus filtering off the solids and yielding the supernatant. Vial O1 yielded no significant supernatant.
10:38--NMR tubes were prepared for A2, A3, O2, and O3; the saturated solutions collected from each vial were mixed with 600uL of CDCl3 in appropriately labelled NMR tubes.
10:43--Vial A2 yielded no supernatant, thus 40 uL of acetonitrile was added to each vial.
10:46--Vial A2 was set in a small beaker filled one-third with water and placed in the sonicator. The temperature was read at 24.0C and the timer was set to 30 minutes.
10:55--Ths supernatants from vials T1, T2, and T3 were collected by pasteur pipette, as the supernatant was cleanly separated from the remaining precipitate.
11:07--NMR tubes were prepared for vial T1, T2, and T3; the saturated solutions collected from each vial were mixed with 600uL of CDCl3 in appropriately labelled NMR tubes.
11:18--Vial A2 was filtered, but yielded no significant supernatant.
13:50--NMR tubes were prepared for M1, M2, M3, D1, D2, and D3; the saturated solutions collected from each vial were mixed with 600uL of CDCl3 in appropriately labelled NMR tubes.

2009-05-19
9:25--The NMRs of all vials were taken on the 300MHz Variac instrument.

References

[1] Solubility of 4-methoxyphenylacetic acid in non-aqueous solvents
[2] Solubility of 4-methoxyphenylacetic acid in THF

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