Researcher

Cuepil Choi

Objective

To observe the effect of water in to formation of acetal production. Kinetics were also studied and observed by NMR

Procedure

An excess amount of ethylene glycol was mixed with 4-chlorobenzadehyde in a 1 dram vial and filtered into another 1 dram vial through a pasteur pipette with a kimwipe plug. The sample of the filtrate was put into a NMR tube and water was added to the remaining filtrate sample. The mixture including water was pipetted into a second NMR tube. HNMR spectra of both NMR tubes were taken at 25 C and then monitered at 75 C.

Results

HNMR 1 - solution s-3 (ethylene glycol and 4-chlorobenzaldehyde) at 25 C
HNMR 2 - solution s-3 with water at 25 C
HNMR 3 - solution s-3 (no water) at 75 C
HNMR 4 - solution s-3 (no water) at 75 C
HNMR 5 - solution s-3 (no water) at 75 C
HNMR 6 - solution s-3 with water at 75 C
HNMR 7 - solution s-3 with water at 75 C
HNMR 8 - solution s-3 with water at 75 C

Discussion

From the current results, the ethylene glycol 4-chlorobenzaldehyde acetal production rates don't seem to be affected by water. However, this experiment will need to be redone because not enough water was added to the system to be noticeable on the NMR spectra. Also, both systems, with and without water, should be carried out to equilibrium so that it can be studied whether acetals degrade in the presence of water.

Conclusion

Both mixtures had acetals come out at around 30 minutes. The rates don't seem to be affected, however, not much water was added since it was hard to determine how much water was added with the NMR. The water peak seems to have combined with the OH peak of the ethylene glycol, since it is not visible. The ratio between the ethylene glycol OH peak and the CH2 peak is still 1:2, which means not enough water was added to throw off the ratio significantly.

Log

2013-08-29

12:46 0.0535 g of 4-chlorobenzaldehyde added to 1 dram vial s-2
12:48 1.6882 g of ethylene glycol added to s-2
12:50 crystals are having trouble going in, mixture in s-2 filtered through a kimwipe plug in a pasteur pipette
12:52 filtrate collected in 1 dram vial s-3. 1.3802 g of filtrate collected
12:53 pipetted into NMR tube 1
12:54 mass of s-3 after NMR tube 1 was filled is 1.2535 g
12:59 0.0506 g of water added to s-3, water goes in after vial is shaken
13:06 NMR tube 2 filled with contents of s-3
13:20 HNMR 1 of NMR tube 1 taken at 25 C and D2O in outer tube
13:28 HNMR 2 of NMR tube 2 taken at 25 C and D2O in outer tube
13:33 NMR machine temperature set to 75 C
13:38 NMR machine temperature reaches 75 C
13:40 HNMR 3 taken of NMR tube 1 at 75.2 C and D2O in outer tube
13:50 HNMR 4 of NMR tube 1 taken at 75 C and D2O in outer tube
14:00 HNMR 5 of NMR tube 1 with 64 scans at 75 C and D2O in outer tube
14:05 NMR tube 1 removed from NMR machine and NMR tube 2 inserted. NMR machine still at 75 C
14:08 HNMR 6 taken of NMR tube 2 with 64 scans at 75 C and D2O in outer tube
14:20 HNMR 7 taken of NMR tube 2 with 64 scans at 75 C and D2O in outer tube
14:33 HNMR 8 taken of NMR tube 2 with 64 Scans at 75 C and D2O in outer tube