Researcher

Matthew McBride

Objective

To measure the LogP of trans-dibenzalacetone by changing the concentration of the 1-octanol solution

Procedure

Mix varying concentrations of 1-octanol with fresh water and measure the solubility of each layer using UV/Vis Spectroscopy.

Results

Vial A: 10% 1-octanol: Water layer
Lambda 2 Spectrometer
Spreadsheet with results of Vial A_water100dilution
λ max: 329 nm
Absorption units at λ max (A): 0.786
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 0.00237 M

Lambda 35 Spectrometer
UV/Vis Spectrum of Vial A_water100dilution
λ max: 333 nm
Absorption units at λ max (A): 0.621881
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 0.00187 M

Vial A: 10% 1-octanol: 1-octanol layer
Lambda 2 Spectrometer
Spreadsheet with results of Vial A_water10000dilution
λ max: 327 nm
Absorption units at λ max (A): 0.058
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 0.0175 M

Lambda 35 Spectrometer
UV/Vis Spectrum of Vial A_water10000dilution
λ max: 324 nm
Absorption units at λ max (A): 0.066272
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 0.0120 M

Vial B: 1% 1-octanol: Water layer
Lambda 2 Spectrometer
Spreadsheet with results of Vial B_water

Lambda 35 Spectrometer
UV/Vis Spectrum of Vial B_octanol100dilution

Vial B: 1% 1-octanol: 1-octanol layer
Lambda 2 Spectrometer
Spreadsheet with results of Vial B_octanol100dilution
λ max: 328 nm
Absorption units at λ max (A): 0.276
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 8.316e-4 M

Lambda 35 Spectrometer
UV/Vis Spectrum of Vial B_water
λ max: 326 nm
Absorption units at λ max (A): 0.350767
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in ethanol: 33190 l·mol-1cm-1
Calculated concentration (c) using Beer's Law (A=εLc): 0.00106M


Vial C: 5% 1-octanol: Water layer
Lambda 2 Spectrometer
Spreadsheet with results of Vial B_octanol100dilution
λ max: nm
Absorption units at λ max (A):
Pathlength (L): 1 cm
Extinction coefficient (ε) of trans-dibenzalacetone in water:
Calculated concentration (c) using Beer's Law (A=εLc): 8.316e-4 M

Discussion

There was some difficultly in measuring the solubility in water.

Conclusion

The logP could not calculated

Log

2012-08-09

17:00 Added 0.100 µL (0.0813 g) of a saturated trans-dibenzalacetone in 1-octanol (Vial B after 10 days of shaking from EXP328- 0.105M) into a 1 mL volumetric flask and filled with fresh 1-octanol. The 1 mL of solution was added to a 1-dram screw cap vial (vial A). 1 mL of distilled water was added vial A. This is a 10% 1-octanol solution.
17:15 Added 50 µL (0.0397 g) of a saturated trans-dibenzalacetone in 1-octanol (Vial B after 10 days of shaking from EXP328- 0.105M) into a 5 mL volumetric flask and filled with fresh 1-octanol. The 5 mL of solution was added to a 20 mL screw cap test tube (vial B) and 5 mL of distilled water was added to the test tube. This is a 1% 1-octanol solution.
17:30 Both vials were sealed with parafilm and placed on the shake flask apparatus in the 25°C water bath.

2012-08-10

8:32 Removed vials A and B from the shake flask apparatus.
8:34 Added 50 µL (0.0504 g) of the bottom layer (water) from vial A into a 5 mL volumetric flask and filled the flask with ethanol to create Solution A_water100dilution.
8:45 Ethanol was placed in both the sample and the control cuvette and this was analyzed by the Lambda 2 Spectrometer. The absorbances at were recorded manually at individual wavelengths. Solution A_water100dilution was placed in the sample cuvette and it was analyzed manually using the Lambda 2 Spectrometer. The sample was also analyzed by the Lambda 35 Spectrometer and the file of the spectrum saved as ONSEXP335A_water100dilution.
9:10 Added 50 µL (0.0391 g) of the bottom (1-octanol) layer from vial A into a 5 mL volumetric flask and filled the flask with ethanol to create Solution B_octanol100dilution.
9:23 Added 50 µL (0.0378 g) of Solution B_octanol100dilution into a 5 mL volumetric flask and filled with ethanol to create Solution B_octanol10000dilution. Sample was analyzed by Lambda 2 Spectrometer by manually recording the absorbance at individual wavelengths and by Lambda 35 Spectrometer. The file of the spectrum was saved as ONSEXPA_octanol10000dilution.
9:55 Added bottom layer of vial B (water) to the sample cuvette and analyzed by both Lambda 2 and Lambda 35 Spectrometers. Used distilled water in the control cuvette, because the sample was not diluted at all. The file of the spectrum was saved as ONSEXP335B_water.
10:39 Added 50 µL (0.0400 g) of the top layer of vial B (1-octanol) to a 5 mL volumetric flask. Filled with ethanol to create Solution B_octanol100dilution. This was analyzed by both Lambda 2 and Lambda 35 Spectrometers. The spectrum of the file was saved as ONSEXP335B_octanol100dilution.
13:11 Added 250 µL (0.2010 g) of the saturated trans-dibenzalacetone in 1-octanol (Vial B after 10 days of shaking from EXP328- 0.105M) in a 5 mL volumetric flask and filled with fresh 1-octanol. Added this solution to a 20 mL screw cap vial and added 5 mL of fresh distilled water. This was vial C and a 5% 1-octanol solution.
13:20 8 mL of fresh 1-octanol and 8 mL of fresh distilled water was added to a 20 mL screw cap vial. This was vial D and was the control.
13:29 Both vials C and D were sealed with parafilm and placed in the 25°C water bath attached to the shake flask apparatus.
14:04 Removed both vials from the shake flask apparatus. Added the bottom layer (water) from vial D to both the control and sample cuvette and analyzed by Lambda 2 Spectrometer. A few small drops of the 1-octanol was visible in both cuvettes. The solution in the sample cuvette was removed. The solution in vial C was poured into a sep funnel and the bottom water layer was added to the sample cuvette. No droplets of 1-octanol were present in this sample. The sample was analyzed by the Lambda 2 Spectrometer.