Question

Outline the best method for preparing the following ketone from an appropriate alchohol in one step. Draw the starting alcohol and select the best reagent.

the list of reagents:
A.Na2Cr2O7, H2SO4
B.LiAlH4
C.NaBH4
D.NaOH

Answer 1

The best method to prepare a ketone from an appropriate alcohol is to oxidize a secondary alcohol such as isopropyl alcohol using sodium dichromate (Na2Cr2O7) in sulfuric acid (H2SO4). This oxidizing reagent will convert the secondary alcohol to the simplest ketone, propanone (acetone). So, the correct option is A.

Step-by-step explanation:

To prepare a ketone from an appropriate alcohol in one step, the oxidation of a secondary alcohol would be necessary. The secondary alcohol that would need to be oxidized to yield a ketone would have the following structure:

H3C - CH(OH) - CH3

This structure represents isopropyl alcohol (2-propanol), which upon oxidation would give propanone (acetone), the simplest ketone. Of the reagents listed, A. Na2Cr2O7, H2SO4 is suitable for oxidizing secondary alcohols to ketones. The formula of the reaction would be:

H3C - CH(OH) - CH3 O (above the arrow) H3C - C(=O) - CH3

It is crucial to note that while secondary alcohols are readily oxidized to ketones, ketones themselves are resistant to further oxidation under these conditions, which makes them easier to isolate without any special precautions.