Researcher

David Bulger

Objective

To verify the solubility of 4-methoxyphenylacetic acid in THF.

Procedure

Saturated solution of 4-methoxyphenylacetic acid in THF made in half-dram vial. After 30 min of sonication, solution filtered with cheese cloth in a Pasteur pipet. The filtrate and enough chloroform-d and added to an NMR tube to create a solution that filled the tube about seven centimeters up (to ensure that the sample filled the NMR detector coil).

Saturated solution of 4-methoxyphenylacetic acid in THF was made in three half-dram vials. After 30 min of sonication, supernatant was separated from precipitate through centrifuging and pipeting. The saturated solution was then prepared for NMR by adding 700 uL of chloroform, 100 uL of saturated solution, and 10 uL of 1,2-dichloroethane.

Results

NMR

ONSCEXP092A
Raw JCAMP-DX File for ONSCEXP092A
ONSCEXP092B
Raw JCAMP-DX File for ONSCEXP092B
ONSCEXP092C
Raw JCAMP-DX File for ONSCEXP092C

Pictures

Note: These photos are compressed. Higher resolution photos are available.
Exp092-01
Exp092-02
Exp092-03
Exp092-04
Exp092-05
Exp092-06
Exp092-07

Spreadsheets

ONSCExp092A - SAMS Measurements
ONSCEXP092B - Internal Standard Measurements


Label
Solubility (M)
ONSCEXP092A
4.30
ONSCEXP092B
4.29
ONSCEXP092C
4.27
ONSCEXP092A
2.01
ONSCEXP092B
2.16
ONSCEXP092C
2.13

Discussion

The solubility of 4-methoxyphenylacetic acid in THF was measured to be 4.30, 4.29, and 4.27 by the SAMS method. The SAMS method gives an approximate range of the solubility. Therefore, the solubility is around 4.2 - 4.4 M. The Internal Standard Signal was overlapped by both the solvent and solute signals. While a calculation of the internal standard area could be made by subtracting the areas of the solvent and solute peaks based on the areas of their other peaks, it has a very large potential for error. Therefore the internal standard measurements in this experiment can be disregarded.

Conclusion

The solubility of 4-methoxyphenylacetic acid in THF was measured to be around 4.2-4.4 M.

Log

2009-05-18

13:00 Added THF to two half-dram vials (samples A and B)
13:10 Added 4-methoxyphenylacetic acid
13:11 Vortexed for 10 sec
13:12 Added 4-methoxyphenylacetic acid
13:13 Vortexed for 10 sec
13:14 Added 4-methoxyphenylacetic acid
13:15 Vortexed for 10 sec
13:22 Sonicated (17 degrees Celsius) [That is pretty low to start sonicating - start with water around 22C at least JCB] I agree.
13:52 Removed from sonicator [You should probably let equilibrate in a 22C water bath for 15 min in the future JCB] Good idea.
13:53 Filtered using cheese cloth in Pasteur pipet and transferred to NMR tubes (A and B)
13:58 Added Chloroform-d
14:01 Measured temperature in sonicator (29 degrees Celsius)

2009-05-19

15:06 Added 700 uL of THF to 3 half-dram vials
15:07 Labeled vials (92-1A, 92-1B, 92-1C)
15:12 Added 4-methoxyphenylacetic acid
15:21 Vortexed for 10 sec
15:22 Added 4-methoxyphenylacetic acid
15:25 Vortexed for 10 sec
15:39 Began sonication (36 degrees Celsius)
15:57 Labeled six half-dram vials (92-2A, 92-2B, 92-2C and 92-3A, 92-3B, 92-3C)
16:07 Removed from sonicator (39 degrees Celsius) - 92-1B completely dissolved
16:09 Photo (Exp092-01)
16:10 Centrifuged vials 92-1A and 92-1C for 2 min
16:14 Photo (Exp092-02)
16:15 Pipeted supernatant from vials 92-1A and 92-1C into vials 92-2A and 92-2C
16:24 Centrifuged vials 92-2A and 92-2C for 2 min
16:25 Solution in vial 92-1B was found to have recrystallized
16:28 Centrifuged vial 92-1B for 2 min
16:29 Pipeted supernatant from vials 92-2A and 92-2C into vials 92-3A and 92-3C
16:31 Photo of 92-3A and 92-3C (Exp092-03)
16:32 Photo of 92-1B (Exp092-04)
16:33 Pipeted supernatant from 92-1B into 92-2B
16:35 Centrifuged 92-2B for 2 min
16:38 Photo of 92-2B (Exp092-05)
16:38 Pipeted supernatant from 92-2B into 92-3B
16:39 Centrifuged 92-3B
16:43 Photo of 92-3A, 92-3B, 92-3C (Exp092-06)
16:53 Labeled NMR prep vials (92-NA, 92-NB, 92-NC)
18:18 Added 700 uL of CDCl3 to NMR prep vials
18:21 Added 100 uL of saturated solutions into corresponding NMR prep vials
18:24 Added 10 uL of 1,2-dichloroethane to NMR prep vials
18:26 Vortexed for 30 sec
18:28 Transferred NMR prep solutions to NMR tubes (92A, 92B, 92C)
18:34 Photo (Exp092-07)
21:00 Parafilmed NMR tubes

2009-05-20

10:32 NMR of ONSCEXP092A
11:20 NMR of ONSCEXP092B
11:53 NMR of ONSCEXP092C

References

1) Moritz, Marshall. Determination of the solubility of 4-methoxyphenylacetic acid in 5 different solvents. 22 May 2009. ONSCExp089. 19 May 2009. http://onschallenge.wikispaces.com/Exp089.

Solubility of 4-Methoxyphenylacetic Acid in Organic Solvents
Solubility of 4-Methoxyphenylacetic Acid in THF (solubility data viewer)

Acknowledgements

The author wishes to thank Dr. Jean-Claude Bradley for the use of his lab and Marshall Moritz for his help in setting up the filtration apparatus.

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