Exp091

Researcher
David Bulger

Objective
To verify the solubility of 4-pyrenebutanoic acid in THF.

Procedure
A 0.75 __M__ solution of 4-pyrenebutanoic acid in THF was made by adding 0.75 moles of 4-pyrenebutanoic acid to 1-mL volumetric flask and filling with THF to the 1-mL mark. The solution was then sonicated to dissolve the 4-pyrenebutanoic acid. However, some of the pyrenebutanoic acid did not dissolve. Therefore solubility of supernatant saturated solution was determined. Semi-Automated Measurement of Solubility ([|SAMS]) was performed in order to verify the solubility of pyrenebutanoic acid.

A 0.60 __M__ solution of 4-pyrenebutanoic acid in THF was made by adding 0.60 moles of 4-pyrenebutanoic acid to 1-mL volumetric flask and filling with THF to the 1-mL mark. The solution was then sonicated to dissolve the 4-pyrenebutanoic acid. However, some of the 4-pyrenebutanoic acid did not dissolve. Therefore solubility of supernatant saturated solution was determined. Two methods were used, Semi-Automated Measurement of Solubility ([|SAMS]) and internal standard of 1,2-dichloroethane, in order to verify the solubility of 4-pyrenebutanoic acid.

NMR
[|ONSCExp091-1A-HNMR] [|Raw JCAMP-DX File for ONSCExp091-1A-HNMR] [|ONSCEXP091] [|Raw JCAMP-DX File for ONSCEXP091]

Pictures
[|exp091-1A_photo1a] [|exp091-1A_photo1b] [|exp091-1A_photo2] [|exp091-1A_photo3] Note: The following pictures are compressed. Higher resolution photos are available if needed. [|Exp091-2A_photo4a] [|Exp091-2A_photo4b] [|Exp091-2A_photo5a] [|Exp091-2A_photo5b] [|Exp091-2A_photo6a] [|Exp091-2A_photo6b] [|Exp091-2A_photo7a] [|Exp091-2A_photo7b] [|Exp091-2A_photo7c] [|Exp091-2A_photo8a] [|Exp091-2A_photo8b] [|Exp091-2A_photo8c]

Spreadsheets
[|ONSCExp091-01] [|ONSCExp091-02] media type="googlespreadsheet" key="rybiSh-LeMAtY9PjcYqinIw" height="400" width="900" media type="googlespreadsheet" key="ruLgwH-6LcugDo8uH5lDN3Q" height="400" width="900"
 * NMR || Molarity of solution if solid had completely dissolved (__M__) || Solubility (__M__) ||
 * [|ONSCExp091-1A-HNMR] || 0.75 || 0.55, 0.64, 0.68 ||
 * [|ONSCEXP091] || 0.60 || 0.76, 0.81, 1.03 ||

Discussion
In Exp061, the solubility for 4-pyrenebutanoic acid in THF was calculated to be 1.39 __M__ and 1.35 __M__ for the methylene protons by SAMS, 1.15 __M__ for the aromatic protons by SAMS, and 0.67 __M__ for the aromatic protons using an internal standard. And in Exp084, the solubility was calculated to be 0.86 __M__ using the acid proton, 0.92 __M__ using the aromatic protons, and 1.03 __M__ and 1.03 __M__ using the methylene protons by SAMS and 0.55 __M__ using an internal standard.


 * Experiment || NMR Signal Used || Method of Solubility Analysis || Solubility (__M__) ||
 * Exp061 || Methylene || SAMS || 1.39 ||
 * Exp061 || Methylene || SAMS || 1.35 ||
 * Exp061 || Aromatic || SAMS || 1.15 ||
 * Exp061 || Aromatic || Internal Standard || 0.67 ||
 * Exp084 || Carboxylic acid || SAMS || 0.86 ||
 * Exp084 || Aromatic || SAMS || 0.92 ||
 * Exp084 || Methylene || SAMS || 1.03 ||
 * Exp084 || Methylene || SAMS || 1.03 ||
 * Exp084 || Methylene || Internal Standard || 0.55 ||
 * Exp091 || Carboxylic acid || SAMS || 0.55 ||
 * Exp091 || Aromatic || SAMS || 0.64 ||
 * Exp091 || Methylene || SAMS || 0.68 ||
 * Exp091 || Carboxylic acid || SAMS || 0.81 ||
 * Exp091 || Aromatic || SAMS || 1.03 ||
 * Exp091 || Methylene || SAMS || 0.76 ||
 * Exp091 || Carboxylic acid || Internal Standard || 0.32 ||
 * Exp091 || Aromatic || Internal Standard || 0.35 ||
 * Exp091 || Methylene || Internal Standard || 0.47 ||
 * [Nice way to summarize the results to date JCB]**

The attempt to make a 0.75 __M__ solution of 4-pyrenebutanoic acid in THF was unsuccessful as some solid precipitated out of solution. The remaining solution was assumed to be saturated, and could therefore be used to determine solubility using SAMS. The solubility was measured to be 0.68 __M__ using the methylene protons, 0.55 __M__ using the carboxylic acid proton, and 0.64 __M__ using the aromatic protons.

The attempt to make a 0.60 __M__ solution was successful at a temperature of 36 degrees Celsius. However, when the temperature decreased to room temperature (19 degrees Celsius), solid precipitated out of solution indicating that this concentration also was not acheived. So SAMS was used again to determine the solubility of the remaining saturated solution, and the solubility was measured to be 0.76 __M__ using the methylene protons, 0.81 __M__ using the carboxylic acid proton, and 1.03 __M__ using the aromatic protons, all of which are greater than the attempted concentration. The source of this error could be evaporation of the solvent during transfer to the NMR tube and/or simply the SAMS method. Either way, the solubility of 4-pyrenebutanoic acid in THF is estimated to be 0.55 - 0.60 __M__.

Note: While the internal standard calculations could be made by subtracting the predicted areas of the overlapping peaks, the margin for error is very large. Therefore, the internal standard measurements can be disregarded.

Conclusion
The solubility of 4-pyrenebutanoic acid in THF is estimated to be somewhere in between 0.55 __M__ and 0.60 __M__.

2009-05-18
15:03 Weighed 4-pyrenebutanoic acid (216.3 mg) 15:10 Inserted into 1-mL volumetric 15:21 Added THF up to 1-mL mark 15:27 Labeled (0.75 M DAB) 15:28 Parafilmed and added copper wire support 15:30 Photo ([|exp091-1A_photo1a]) 15:31 Photo ([|exp091-1A_photo1b]) 15:32 Sonicated (24 degrees Celsius) 15:59 (38 degrees Celsius) 16:14 Sonication ended 17:14 Removed from sonicator (27 degrees Celsius) 17:16 Added THF up to 1-mL mark **[How much did you add roughly? JCB]** Just a few drops. 17:20 Parafilmed and added copper wire support 17:22 Photo ([|exp091-1A_photo2]) 17:22 Sonicated (26 degrees Celsius) 17:26 Removed from sonicator **[Why only 4 min? JCB]** I was going to sonicate it longer to let it dissolve, but decided to run NMR. 17:27 Transferred supernatant to vial and labeled (91-1A) 17:30 Photo ([|exp091-1A_photo3]) 17:32 Centrifuged vial for 2 min 17:36 Added DMSO (700 uL) to NMR tube 17:37 Centrifuged vial for less than 1 min 17:38 Added supernatant from vial (100 uL) to NMR tube 17:44 Obtained NMR spectrum (Gain = 10) on 500 MHz spectrometer **[Name the spectrum JCB]** ([|ONSCExp091-1A-HNMR]) Note: There are still some spinning side bands. 18:09 Parafilmed volumetric flask and vial

2009-05-19
14:25 Weighed 1-mL volumetric flask (15.587 7 g) 14:27 Added 4-pyrenebutanoic acid into volumetric flask 14:43 Weighed flask with acid (15.760 5 g) 14:44 Added THF up to 1-mL mark 14:50 Labeled volumetric flask (91-2A) 14:52 Photos ([|Exp091-2A_photo4a], [|Exp091-2A_photo4b]) 14:55 Cleaned off label and weighed volumetric flask (16.513 8 g) 14:56 Relabeled, parafilmed, and added copper wire support 14:57 Sonicator temperature at 27 degrees Celsius 14:58 Began sonication 15:02 Vortexed for 10 sec 15:02 Sonicated 15:27 Reparafilmed (old parafilm melted) 15:28 Removed from sonicator 15:37 Sonicator temperature at 36 degrees Celsius 15:38 Photos ([|Exp091-2A_photo5a], [|Exp091-2A_photo5b]) - solute completely dissolved 16:45 Photos ([|Exp091-2A_photo6a], [|Exp091-2A_photo6b]) 16:51 Labeled NMR prep half-dram vial (91-NA) 18:05 Photos ([|Exp091-2A_photo7a], [|Exp091-2A_photo7b], [|Exp091-2A_photo7c]) - solvent evaporated slightly, temperature decreased to room temperature (19 degrees Celsius), and some solid precipitated 18:06 Added THF up to 1-mL mark 18:10 Parafilmed 18:12 Vortexed for 1 min 18:15 Photos ([|Exp091-2A_photo8a], [|Exp091-2A_photo8b], [|Exp091-2A_photo8c]) - did not go back into solution at room temperature 18:45 Added 700 uL CDCl3 to 91-NA 18:48 Pipeted saturated solution from volumetric flask into another half-dram vial 18:49 Added 100 uL saturated solution from half-dram vial to 91-NA 18:51 Added 10 uL 1,2-dichloroethane to 91-NA 18:52 Vortexed for 30 sec - did not go into solution (need to use DMSO-d6 instead of CDCl3) 19:05 Added 700 uL of DMSO-d6, 100 uL of saturated solution, 10 uL of 1,2-dichloroethane to another half-dram vial 19:14 Vortexed for 30 sec 19:19 Transferred to NMR tube (91) using Pasteur pipet 21:00 Parafilmed NMR tube

2009-05-20
12:05 NMR of [|ONSCEXP091]

Acknowledgements
The author wishes to thank Dr. Jean-Claude Bradley for the use of his lab and Khalid Mirza for his help with the NMR.