Purification of Phenylacetaldehyde


Objective

To purify phenylacetaldehyde by distillation.

Procedure

To a 100mL round bottom flask and added approx 15-20mL of phenylacetaldehyde. The distillation was carried out under ambient pressure and open to air. Picture of similar setup.

Results

Characterization of 37-F1

Clear oil with small droplets suspended, 5 mL (approx) HMR

Discussion

Although the HMR of 37-F1 shows reasonable purity for use as a reagent, it appears contaminated with droplets floating and sticking to the sides of the flask. This may be water condensed by the distillation in open air. Future distillation should be done under nitrogen.
Phenylacetaldehyde is reported to boil at 195C. Since 37-F1 was collected at 162C (approx), perhaps this corresponds to an azeotrope with water and would explain the contamination in the first fraction. In the future more careful measurement of the Ubergang temperature over the course of the distillation would help to clarify this issue.

Conclusion

The distillate cannot be used due to contamination and should be redone under an inert atmosphere.

Log

2006-10-06

1. [13:00](approx) Using a 100mL round bottom flask, added phenylacetaldehyde (approx 15-20mL). Attached r.b.f. to a normal distillation apparatus under a mantle using a rheostat with a 25mL r.b.f. as the capturing flask. 260C alcohol thermometer was used. Set rheostat to 6.5 and the setup was open to air. Setup was the same as the picture describes however the picture was taken after the experiment ended and the water tubes were removed.
2. [13:15] (approx) After approx 15minutes, distillant was noticed to come off at 162C.
3. [13:20] (approx) Once 5mL 37-F1 was collected, started to collect new fraction in 25mL r.b.f. Put 37-F1 under nitrogen, and it is a clear liquid. Took HMR.
4. [13:50] (approx) Collected 37-F2, yellowish color, and put under nitrogen.

Tags

Phenylacetaldehyde, InChI=1/C8H8O/c9-7-6-8-4-2-1-3-5-8/h1-5,7H,6H2