CRSEXP005

Chemspider links: [|octanoic acid] [|water] =Researcher= Cuepil Choi =Objective= To examine how octanoic acid saturated with water looks on the HNMR spectrum and water saturated with octanoic acid. Follow up of CRSEXP004 =Procedure= Approximately 1:1 volume of octanoic acid and water were pipetted into a test tube and vortexed. The solution was left to settle for about 3 hrs and the individual layers were filtered through a kimtech wipe inside a small pasteur pipette and the filtrate was put into NMR tubes. HNMR spectra were taken at 26.5 C with deuterated chloroform in an outer tube. =Results= [|HNMR spectrum 1] - octanoic acid saturated with water [|HNMR spectrum 2] - water saturated with octanoic acid =Discussion= The shifts may mean that we might be able to observe the amount of water in the octanoic acid with the position of the shift. It is also puzzling why the peak did not shift down to 10 ppm as we observed when we mixed the octanoic acid with water in CRSEXP004. =Conclusion= There was no peak at 4.8 ppm in HNMR spectrum 1 as we observed when we mixed the octanoic acid and water in the NMR tube. The most downfield proton that was observed at 12.33ppm in pure octanoic acid moved down to 11ppm. HNMR spectrum 2 showed a peak at 4.77. This peak representing water saturated with octanoic acid is significantly shifted from its normal 4.8ppm peak when it is pure. An impurity was labeled at 1.57ppm which was labeled as acetone. =Log=

2013-07-11
12:54 octanoic acid pipetted into test tube 12:59 water pipetted into test tube, water sank to bottom and two layers formed. approximately 1:1 ratio by volume 13:00 vortexed for approximately 20 seconds 14:50 acid layer taken from top and filtered through a kimtech wipe filter in a small pasteur pipette. 15:01 air blown through pipette to accelerate filtering. Filtered acid pipetted into NMR tube 15:30 water layer taken from top and filtered through kimtech wipe filter in a small pasteur pipette 15:41 filtered water put into NMR tube 17:05 HNMR spectrum 1 taken of NMR tube with octanoic acid saturated with water at 26.5 C with outer tube of deuterated chloroform. TMS peak set to 0 ppm 17:10 HNMR spectrum 2 taken of NMR tube with water saturated with octanoic acid at 26.5 C with outer tube of deuterated chloroform. TMS peak set to 0 ppm