Carbonyl Compounds

Carbohydrates
 Elmhurst College
Synthesis - Aldehydes/Acids Reduction  Synthesis - Acetals  Chemistry Department
Synthesis - Ketones Synthesis - Hemiacetals  Virtual ChemBook

 GENERAL EQUATION: OXIDATION OF SECONDARY ALCOHOLS

secondary alcohol + (0) --> ketone + HOH

reducing agent oxidizing agent

Synthesis of Ketones

 

Synthesis of Ketones - Oxidation of Secondary Alcohols:

Aldehydes and ketones are synthesized by the oxidation of various kinds of alcohols.

The definitions which are used in inorganic chemistry involving the gain or loss of electrons; or the increase or decrease in oxidation numbers are not very useful in organic chemistry. In organic chemistry, although changes in electrons are important, oxidation and reduction is more readily observed from changes in the number of hydrogen or oxygen atoms. The definitions are as follows:

OXIDATION: loss of hydrogen, gain in oxygen, or loss of electrons

REDUCTION: gain of hydrogen, loss of oxygen, or gain of electrons.

The oxidation of secondary alcohols yields ketones. In the oxidation of an alcohol, the oxidizing agent, usually represented by (0), removes the hydrogen and electrons from the alcohol, the reducing agent. The "0" in the oxidizing agent is some unspecified oxygen atom which reacts with the hydrogen atoms to form water.

The oxidation of a secondary alcohol leads to the formation of ketones. This relationship should be clear if you carefully consider the position of the -OH group in a secondary alcohol and the position of the carbonyl group in a ketone. Both functional groups are not on a terminal carbon. On the other hand, a primary alcohol and the aldehyde are on the terminal carbon.

Synthesis of an Ketone:

 

Example:

1) The hydrogen on the carbon is removed along with 2 electrons.
2) The hydrogen is removed from the oxygen as Hydrogen ion.
3) The two electrons which were bonded to hydrogen are used to form the double bond.
4) The H with 2 electrons, the hydrogen ion, and O (oxygen) from the oxidizing agent form a water molecule.