Researcher

Jenna Mancinelli

Objective

To generate a solubility-temperature curve for boc-glycine in THF.

Procedure

Label seven vials, into which approximately 0.1 g THF is pippetted. The appropriate amount of boc-glycine is added to each vial. Each vial is parafilmed tightly and vortexed for 15 seconds. All seven vials are placed into heating-cooling thermostat with 60% water and propylene glycol bath set to 40C until all mixtures become unsaturated. Once all vials have reached solution, the temperature of the bath is lowered in 1 to 2 degree increments. The temperature at which precipitates occur is recorded.

Results

Spreadsheet

Jenna135.JPG

Discussion

From the solubility-temperature curve obtained, it can be predicted that the solubility of boc-glycine in THF at 23C would be 4.35 M. These results are within the standard deviation, 0.5636, of the average, 3.99 M, of other findings. The results listed from Experiment 071 and Experiment 207 do not have recorded temperatures, and therefore may have been recorded at temperatures either higher or lower than room temperature, therefore explaining the difference in values. Additionally, these results add to and are consistent with the solubility-temperature curve obtained in Experiment 133, which found the solubility of boc-glycine in THF at 23C to be 4.4977 M.

Conclusion

A solubility-temperature curve was obtained for boc-glycine in THF.

Log

2009-08-17
14:30 Labeled 5 vials. Vial weight is 2.244 g.
14:50 Pippetted approximately 0.11 g THF to each vial. Weighed and added varying amounts boc-glycine to each vial. These values are recorded in the spreadsheet.
15:25 Parafilmed each vial and vortexed each for 15 seconds. Vials 1 and 2 are in solution at room temperature, 23C.
15:55 All 5 vials placed into in heating-cooling thermostat with 60% water and propylene glycol bath set to 40C.
16:20 All 5 vials have reached solution and appear to be unsaturated. Begin to drop temperature of bath.
18:00 Prepared two more vials, Vial 6 and Vial 7, of higher concentrations for continuation of experiment at later time. Parafilmed vials tightly. Both saturated at room temperature.
18:35 First five vials have precipitated out and the temperature of each has been recorded. All vials left at room temperature, 23C, until the experiment can be completed.

2009-08-20
10:20 Placed Vials 6 and 7 into in heating-cooling thermostat with 60% water and propylene glycol bath set to 40C.
11:30 Removed vial 7 from bath because it will not reach solution within safe temperature range. Left Vial 6 in bath and began to lower temperature.
12:15 Vial 6 showed precipitate at 17C. Removed vial from bath.