Experiment II Steam Distillation

3

Extraction of The Natural Producttrans-Cinnamaldehydefrom Cinnamon Bark

Abstract

The mainobjective of the current experiment was to isolate the naturalproduct trans-Cinnamaldehyde from Cinnamon Bark. The mass of thecinnamon bark used during the experiment was 1005mg. The isolationwas done using steam distillation process where the solid cinnamonwas boiled in deionized water and resulting steam containingcinnamaldehyde was condensed and collected. The steam distillationprocess led to a recovery of 69mg aldehyde, which is equivalent to6.9% yield. Infrared spectrum was used to verify that the substancecollected was purely cinnamaldehyde.

Structureof Cinnamaldehyde

Cinnamaldehydecontains the formyl group that makes it an aldehyde. The structure ofcinnamaldehyde contains a phenyl group that is attached to thealdehyde, hence the name 3-phenyl-2-propenal. Trans-cinnamaldehydemolecule is made up of benzene ring attached to uninsulated aldehyde.This is as shown below.

Procedure

1g ofchopped stick and 4ml of water was placed in a 10ml round bottomedflask. The flask was attached to the Hickman-Hinkle still fitted withan air condenser. The apparatus was placed in a sand-bath at150oC-160oC.The Hickman-Hinkel still was insulated using aluminium foil tent. Thebulb was placed into the throat of the Hickman-Hinkel still andtemperatures recorded. The cap was unscrewed on the side arm in orderto remove the liquid when almost full. The liquid was cinnamaldehyde.A Pasteur pipette was used to remove the liquid and water was addedto restore the original volume in the flask. The heat was turned offafter enough distillate was collected.

Thedistillate, which contained cinnaldehyde and water was extractedusing methylene chloride. 2ml of methylene chloride was to thedistilled fractions and the culture tube shaken to effect theextraction process. Two layers formed, with most of cinnamaldehydeforming at the bottom dissolved organic layer. The dissolved layerwas extracted using Pasteur pipette and transferred to the cleanculture tube. The process was repeatedly done until an approximately6mL combined organic layer was obtained. Anhydrous sodium sulphatewas added to the culture tube containing the organic layer. Sodiumsulphate acted as last line of drying defence and helped in filteringout any solids that were accidentally drawn up. Finally, the culturetube was left uncapped in a test tube rack. This was to allow theevaporation of methylene chloride whose boiling point is 39.6oCleaving behind trans-cinnamaldehydethat evaporates at 248oC.

Results

Mass (mg)

Temperature

% Recovery

Cinnamon Bark

1005 mg

95°C

6.9%

Culture tube

11498 mg

Cinnamon Aldehyde

69 mg

Culture tube + Cinnamon Aldehyde

11567 mg

Mass of thepredicted yield for cinnalmaldehyde was 1005. The total mass of thecinnamaldehyde and culture tube was 11567mg. Mass of the culture tubewas 11498mg. Therefore, the mass of cinnaldehyde collected was 69mg.

Calculations

From the literature value,percentage yield of cinnamon is 2 percent.

Sourcesof Errors

Some of the possible sources oferrors for this experiment include both the human and measurementinstrument errors.

Conclusion

The main aim of the experimentwas to isolate the natural product, trans-cinnamladehydefrom cinnamon bark using steam distillation process. Cinnamaldehydeis soluble in steam but insoluble in water. The distillate, whichcontained cinnamaldehyde and water was removed and methylene chlorideadded to separate the two cinnamaldehyde and water. Cinnamaldehydeformed an organic solution with methylene chloride, which wasseparated from water. The anhydrous sodium sulphate was added tonecessitate the drying process and filter any unwanted solids.Thereafter, the trans-cinnamaldehyde-methylenechloride mixture was left to separate. Methylenechloride whose boiling point is 39.6oCeveporated leaving behind trans-cinnamaldehydeas clear white crystals with a characteristic smell of cinnamon.

Thetheoretical value for the cinnamaldehyde recovery is 4%. However, thevalue obtained (6.9%) was considerably higher maybe due to humanerrors in taking measurements or equipment errors such as poorcalibration of the equipment For instance, there was high likelihoodthat some traces of the cinnamaldehyde remain in the tube duringextraction or use of too much make up water during distillationprocess.

To test forthe purity of the cinnamaldehyde obtained, an infrared spectrum wasused. The reference chart was availed by the instructor during theexperiment. The peak points in the chart represented the location ofthe functional groups where the organic compound is required to takemost of the infrared light. However, due to impurities in thecinnamaldehyde corrected which could have been caused by experimentalerrors, it was not possible to obtain accurate peaks for thecinnamaldehyde obtained in the current experiment.