The aldehyde contains a terminal carbonyl group, and is classified as an organic compound. This functional group consists of a carbon atom bonded to a hydrogen atom and double boned to an oxygen atom and is known as the aldehyde group as well as the formyl or methaniyl group. Aldehyde reactions can come in the form of an addition reaction, nucleophilic reaction, reduction or oxidation reactions. In the past some aldehydes were named after the corresponding alcohols like ‘vinous aldehyde’ from the Latin ‘vinum’ meaning wine. With the fact that oxygen is more electronegative then carbon, it pulls the electrons of the carbon-oxygen bond inwards or towards itself. That is why the aldehyde group is known as polar.
There are several methods for preparing aldehyde reactions for synthesis. Reacting with a primary alcohol with a chromium oxidizing agent. This is achieved by heating he alcohol with an acidified solution of potassium dichromate. The extra dichromate will continue to oxidize the aldehyde to a carboxylic acid. This means that either the aldehyde is distilled out as it is made, or a milder reagent such as PCC is used. The oxidation of primary alcohols into aldehydes may be realized under chromium free conditions by using
One of the common aldehyde reactions is the reduction or oxidation reaction. The aldehyde can be reduced by changing the aldehyde into a primary alcohol. Another aldehyde reaction can also include the group being oxidized which will result in a cabonxylic acid. Some of the potential oxidizing agents can include potassium permanganate, nitric acid, chromium (VI) oxide, and acidified potassium dichromate. When the combination of manganese dioxide, methanol and acetic acid is used, this will result in the turning the aldehyde into a methyl ester.
The silver mirror test is another aldehyde reaction method using oxidation. The aldehyde is treated with Tollens reagent, which is set a up by adding a drop of sodium hydroxide solution into a silver nitrate solution to give an accelerated silver oxide. Then the minimal amount of ammonia to dilute it. The ammonia solution re-dissolves the accelerated in aldehydes to carboxylic acids, all without attacking carbon-carbon double bonds, forming a more complex compound. If the aldehyde does not form an enlote, then the addition of a strong base will cause the Cannizzaro reaction to happen, producing a mixture of alcohol and carboxylic acid.
Another form of aldehyde reactions is called a nucleophilic addition reaction. A nucleophile has the ability to add to the carbon atom in the carbonyl group. This will result in an addition compound where the carbon atom has a tetrahedral molecular geometry. This reaction along with protonation of the oxygen atom in the carbonyl group results in a product that has the carbon atom in the carbonyl group bonded to the nucleophile, a hydrogen atom in the hydroxyl group. In a lot of instances, a water molecule is taken away after the addition takes place. In the preceding case the reaction is classified as an addition-elimination or addition-condensation reaction.
reagents such as IBX acid, peridinane, TEMPO, Dess-Martin, Oppenauer oxidation or Swern oxidation.