Researcher

Hai Truong & Khalid Mirza





UC176C
benzoic acid
phenylacetic acid
1-octanol

Objective
To measure the solubility of the benzoic acid, phenylacetic acid and the Ugi product UC176C in 1-octanol.
Results from this experiment will be used to compare the predicted solubility obtained from the Abraham solvation equations. Abraham solvation equation states that the solubility of the solute in the solvent can be estimated from the predicted partition constant.
Abraham' solvation eqution
log P_s = c + e E + s S + a A + b B + v V
See Benzoic acid - Abraham

Procedure

Saturated solutions of Ugi product UC176C, benzoic acid and phenylacetic acid was prepared in 1-octanol in one dram vials, by adding the solute to a small amount of the solvent. It was ensured that no more solute dissolved any further at room temp..The vials were placed in a temperature controlled water/glycol bath at 50C for two days. The samples were then left to equlibrate at 25C for three hours. Solubility was estimated by SAMS from HNMRs of the supernatants in DMSO-d6.

Results

Exp155-Spreadsheet
Sample ID
Solvent
Solute
Solubility (M)
A-1
1-octanol
Ugi UC176C
0.01
A-2
1-octanol
Ugi UC176C
0.01
B-1
1-octanol
benzoic acid
1.48
B-2
1-octanol
benzoic acid
1.49

Discussion

Inconsistent values for phenylacetic acid concentration suggest that a solubility run for the acid has to be repeated.

Conclusion

Solubility of benzoic acid in 1-octanol has been determined to be ~1.5M, and for Ugi product UC176C it was 0.01M

Log

12-11-2009
15:15 Took out 3 half dram vials. Label A, B and C.
15:20 Pipetted out 1000uL of 1-octanol into 3 vials.
15:35 For:
Vial A-1: Put small amount of Ugi176C so that there was still small amount of solid remained in the solution.
Vial B-1: Put small amount of benzoic acid so that there was still small amount of solid remained in the solution.
Vial C-1: Put small amount of phenylacetic acid so that there was still small amount of solid remained in the solution.
15:45 Parafilmed all 3 vials
15:50 Put them into the bath. Adjusted to 60C from 23C
16:10 Altered the setting on the temperature bath to 50C. [record actual bath temperature also JCB]- [ok- I forgot, I will pay more attention to this next time- Hai Truong]
16:15 Took out other 3 half dram vials. Label A-2, B-2 and C-2.
Vial A-2: Put small amount of Ugi product UCExp176C so that there was still small amount of solid remained in the solution.
Vial B-2: Put small amount of benzoic acid so that there was still small amount of solid remained in the solution.
Vial C-2: Put small amount of phenylacetic acid so that there was still small amount of solid remained in the solution.
16:35 Parafilmed all and put them in to the Lauda heating/cooling bath.
19:35 Adjusted temperature in the bath to 40C. Bath at this time was at 50C.
12-13-2009
17:55 Changed the temperature setting on the bath from 40C to 25C. Checked and made sure all the sample vials appeared ok-no leak!
21:05 Removed the vials from the temp control bath at 25C, vials C-1 and C-2 did not have any solid in them, these contained phenylacetic acid as solute. These vials were discarded. In the remaining vials some pretty crystal were observed.
21:10 Carefully pipetted out approximately 400-500uL of supernatant from vials A-1, A-2, B-1 and B-2 was transferred in to four clean NMR tubes containing DMSO-d6 (200uL)
21:45 Obtained HNMR of 1-octanol in DMSO-d6
22:40 Completed obtaining HNMRs, labeled ONSCExp155-A-1, ONSCExp155-A-2, ONSCExp155-B-1 and ONSCExp155-B-2
12-15-2009
12:50 To the sample vials C-1 and C-2 which contained only clear solutions of phenylacetic acid in 1-octanol, extra phenylacetic acid was added, they were vortexed for 30s.
12:55 Placed vials C-1 and C-2 in to a sonicator and started sonicating them.
13:05 After sonication for 10min, some solid still remained in the vials.
13:07 Placed the vials in to the water/glycol bath of a temperature control device (Lauda thermostated bath) with its temperature at 27C, then set the thermostat at 60C
20:20 Changed the thermostat setting from 60C to 25C.
12-16-2009
12:15 Turned off the thermostat and removed the vials. (Temp at 25C). Nice crystals were observed at the bottom of the vials.
12:20 In to two clean/dry NMR tubes, pipetted out a volume (~200uL) DMSO-d6 and labeled the tubes ONSCExp155-C-1 and ONSCExp155-C-2.
12:25 Transferred approximately 500uL of the supernatant from each vial in to the corresponding NMR tubes.
14:20 Obtained HNMRs of ONSCExp155-C-1 and ONSCExp155-C-2