Reduction-Oxidation

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[pic 5]

Indicate here the movement of electrons by oxidation numbers

Fourthly, the hypochlorite oxidant is protonated by the acetic acid in this experiment. Acetic acid is a weak acid and strong acids are not advisable to use such as HCl or H2SO4 because ??????

Lastly, to guarantee that cyclohexanone is isolated from the other components to ensure maximum yield and purity, the process of salting out should be conducted. It is because cyclohexanone is slightly soluble in water due to its capability to form a hydrogen bond with water but using NaCl which water has more affinity (Ionic bonding > H-bonding) rather than cyclohexanone, water in the aqueous layer will become saturated with NaCl leaving the cyclohexanone behind making the isolation more successful (Mayo, et al., 2011).

Lastly, steam distillation will be used in this experiment because the boiling points of the starting material, cyclohexanol, and the desired material, cyclohexanone, are near to each other. Cyclohexanol boils at 161.5 deg C while Cyclohexanone boils at 155 deg C. Using steam distillation, their boiling points is also lowered to a more bearable point in which the codistillation of the two is avoided.

(Isama mo pa dito ung sa Raoult’s Law!)

After the final product is separated from the rest, it will be subjected to characterization tests which will verify its identity. The first test is the Jones test. As indicated previously above, the presence of opaque green mixture confirms that the final product is still cyclohexanol. But if not, then the final product is the desired product which is cyclohexanone.

(search for the mech of Jones test to cyclohexanol and cyclohexanone!!!!)

Another test to be conducted is the reaction of the two with warm, dilute, neutral KMnO4.

(search this also!)

The final product will also be subjected with 2,4-DNP to undergo derivatization and the hydrazones that will be formed will follow the mechanism (Hill & Barbaro, 2000):[pic 6]

Formation of yellow to red precipitate is observed mostly in aldehydes and ketones but some may require application of heat before precipitate can be observed (Hill & Barbaro, 2000).

In this exercise, the students should be able to:

- Define the term oxidation as defined in the general chemistry and organic chemistry;

- Perform steam distillation and extraction procedures.

- Compare the reaction of the starting material and product with the jones reagent and warm, dilute, neutral KMnO4

- Perform a derivatization procedure of cyclohexanone using 2,4-DNP.

References

Journal of Organic Chemistry, 1980

Retrieved at :

D.W Mayo, R.M Pike, D.C Forbes “Microscale Organic Laboratory with multistep and multiscale syntheses” 5th ed. 2011 John & Wiley Sons, Inc.

F. Carey “Organic Chemistry” 5th ed. Pg 87-90; Pg.(641-645)

“Compounds containing the ketone or aldehyde” “Exp 3 Oxidation of alcohols: Preparation of cyclohexanone” 2004 Online edition for students of org chem lab courses at University of Colorado, boulder, dept of chem and biochem

Retrieved at:

“Experiment 9 Oxidation of Cyclohexanol toCyclohexanone”pdf

Retrieved at:

“Experiment 8 Preparation of Cyclohexanone by Hypochlorite Oxidation” pdf

Retrieved at:

R.K. Hill; J. Barbaro “Experiments in Org Chem” 2nd ed. (2000) Contemporary Publishing of Raleigh, Inc.

R.V Stevens; K.T. Chapman; H.N. Weller “Convenient and inexpensive procedure for oxidation of secondary alcohols to ketones” (1979) Dept of Chem, Univ. of California, Los Angeles, California

List of necessary chemicals

Acetic acid, Ca(OCl)2, NaHSO3, Anhydroud MgSO4 , Na2SO4, Jones reagent, KMnO4, 95% etoh, 2-4,DNP

[pic 7]

Set ups

Simple distillation, Steam distillation, Extraction [pic 8]