Preparation of 2-Acetylcyclohexanone Essay example

Words: 1755
Pages: 8

Introduction 3
Results 4
Discussion 6
Conclusion 7
Experimental 7
References 8

Preparation of 2-Acetylcyclohexanone
When hydrogens are present on the α-carbon of ketones (like the reaction used in this experiment), carbonyl compounds and aldehydes, they turn the compound slightly acidic1. These functional groups are removed by using a basic solution as shown in (i) below1. The product formed with water is stable only due to resonance, but does not form a very stable equilibrium.

Enamine reactions are used to avoid many problems usually associated with alkylating or acylating carbonyl compounds when they are reacted with aqueous sodium hydroxide1 as shown in reactions (ii) and (iv)1.
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The melting point range obtained experimentally was 110-119ºC and is very different from the theoretical melting point range due to errors that have occurred during the procedure of the practical and are explained in the discussion above. The particularly low % yield of 2.10% is due to insufficient reflux time.

Preparation of the toluene solution of the enamine
A 100ml round bottomed flask was pre-weighed, after which cyclohexanone (5.0ml), pyrrolidine (4.0ml), toluene-4-sulfonic acid (0.1g) and 40 ml toluene were added to it. 4 boiling chips were also added to the reagent mixture so as to prevent loss of product due to splashing and boiling of the product. The Dean and Stark apparatus was set up individually by each student. The 100 ml round bottomed flask with reagent mixture was then fit to the Dean and Stark apparatus with a reflux condenser fit to the top of the apparatus. The reflux condenser was fit with a calcium chloride drying tube in order to prevent atmospheric moisture from reacting with the contents of the round bottomed flask, and also to serve as a means to relieve pressure formed during the reaction. A heating mantle was used to heat the round bottomed flask till a vigorous reflux of the toluene, with vapour rising up the condenser was observable. It was observed that the water that