Researcher

Matthew McBride

Objective

To determine the solubility of trans-dibenzalacetone in n-hexane, cyclohexane, methanol, 2-propanol and a ethanol/water(50:50)vol mixture at 25°C using SAMS HNMR and the Shake Flask method

Procedure

Add a small amount of the trans-dibenzalacetone crystals to a 1-dram screw cap vial with the appropriate solvent so that crystals are visible in the solution. Seal the vial and attach to the shake flask apparatus and submerge in the 25°C water bath. After 3 and 5 hours of shaking, analyze the supernatant of each solution to measure the solubility using SAMS HNMR.

Results

SAMS Sheet 1: Solubility in n-hexane at 25°C - Vial A
3 Hours: Cannot integrate spectrum due to phasing error
5 Hours: Cannot integrate spectrum due to phasing error

SAMS Sheet 2: Solubility in cyclohexane at 25°C - Vial B
3 Hours: 0.034M
5 Hours: 0.02M

SAMS Sheet 3: Solubility in methanol at 25°C - Vial C
3 Hours: 0.104M
5 Hours: 0.086M

SAMS Sheet 4: Solubility in 2-propanol at 25°C - Vial D
3 Hours: 0.081M
5 Hours: 0.088M

SAMS Sheet 5: Solubility in 1:1 ethanol/water (vol) at 25°C - Vial E
3 Hours: No solute present
5 Hours: No solute present

Picture #1 of vials secured to stand
shake flask pic1.png

Picture #2 of vials attached to the vortex genie and submerged in the 25°C water bath
shake flask pic2.png

Discussion

Vial A: The solvent selector shows that Model003 predicted the solubility to be 0.059M. The solubility could not be calculated due to a phasing error on the NMR spectrum.
Vial B: Model003 predicted a solubility of 0.160M for dibenzalacetone in cyclohexane and the measured solubility was 0.02M, so the prediction was a little high. The solubility did not change from 3 hours to 5 hours of shaking, so the solution was saturated after 3 hours of shaking.
Vial C: Model003 predicted a solubility of 0.140M and the measured solubility was 0.086M, so this was an accurate prediction. Solution was saturated after 3 hours of shaking.
Vial D: Model003 predicted a solubility of 0.125M and the measured solubility was 0.088M, so this was an accurate predication. Solution was saturated after 3 hours of shaking.
Vial E: Model003 predicted a solubility of 0.004M, but no solute appeared in the NMR spectrum of the supernatant, so it seems this prediction of basically no solubility is accurate.

Conclusion

At 25°C, trans-dibenzalacetone has a solubility of 0.02M in cyclohexane, 0.086M in methanol, 0.088M in 2-propanol and around 0M in the ethanol/water(50:50)vol mixture.

Log

2012-07-23

11:05 0.1108 g of trans-dibenzalacetone (Product 284A from UCEXP284) placed in a 1-dram screw cap vial (Vial A).
11:08 0.1007 g of dibenzalacetone placed in Vial B.
11:10 0.1213 g of dibenzalacetone placed in Vial C.
11:13 0.1172 g of dibenzalacetone placed in Vial D.
11:15 0.1310 g of dibenzalacetone placed in Vial E.
11:28 Approximately 0.75 mL of n-hexane added to Vial A. Crystals visible.
11:31 Approximately 0.75 mL of cyclohexane added to Vial B. Crystals visible.
11:33 Approximately 0.75 mL of methanol added to Vial C. Crystals visible.
11:36 Approximately 0.75 mL of 2-propanol added to Vial D. Crystals visible.
11:44 In a 5-dram vial, 0.6515 g of ethanol (0.828 mL) and 0.8362 g of distilled water (0.836 mL) were mixed together. Approximately 0.75 mL of this 1:1 mixture by volume was added to Vial E. Crystals visible.
11:52 The vials were sealed with parafilm and attached to the Shake Flask apparatus and then submerged in the 25°C water of the water bath. The vortex of the apparatus was set to level 2.
14:35 The vials were removed from the Shake Flask apparatus. Crystals were visible in all of the vials.
14:50 A few drops of the supernatant from Vial A was transferred to the inner coaxial NMR Tube 1. A few drops of the supernatant from Vial B was transferred to the inner coaxial NMR Tube 2. A few drops of the supernatant from Vial C was transferred to the inner coaxial NMR Tube 3. A few drops of the supernatant from Vial D was transferred to the inner coaxial NMR Tube 4. A few drops of the supernatant from Vial E was transferred to the inner coaxial NMR Tube 5.
14:55 Each of the vials were sealed with parafilm and placed back on the Shake Flask apparatus and submerged in the 25°C water.
16:00 The NMR tubes were placed in a outer NMR tube containing CDCl3 and analyzed by 500MHz HNMR. The files of the spectrums were saved as ONSEXP324VialA_3hours, ONSEXP324VialB_3hours, ONSEXP324VialC_3hours, ONSEXP324VialD_3hours and ONSEXP324VialE_3hours.
16:52 The vials were removed from the Shake Flask apparatus. Crystals were visible. A few drops of the supernatant from Vial A was transferred to the inner coaxial NMR Tube 6. A few drops of the supernatant from Vial B was transferred to the inner coaxial NMR Tube 7. A few drops of the supernatant from Vial C was transferred to the inner coaxial NMR Tube 8. A few drops of the supernatant from Vial D was transferred to the inner coaxial NMR Tube 9. A few drops of the supernatant from Vial E was transferred to the inner coaxial NMR Tube 10.
17:30 The NMR tubes were placed in a outer NMR tube containing CDCl3 and analyzed by 500MHz HNMR. The files of the spectrums were saved as ONSEXP324VialA_5hours, ONSEXP324VialB_5hours, ONSEXP324VialC_5hours, ONSEXP324VialD_5hours and ONSEXP324VialE_5hours.