Vanillin is an aromatic aldehyde obtained from vanilla pods.
Aldehydes are organic molecules, which means they are made of carbon atoms. They can be distinguished from other organic molecules because they contain an aldehyde or formyl group. This group is made up of a carbon atom bonded to a hydrogen atom and an oxygen atom by a single and double bond, respectively. Aldehydes are just one of many different types of organic molecules and compounds. They differ greatly in their physical properties and are normally formed by the oxidation of an alcohol.
Ketones and aldehydes are very similar in that they both have carbon atoms double bonded to oxygen; They are called carbonyl groups. Aldehydes can be distinguished from ketones based on the location of the carbonyl group. It is found at the end of the molecule in an aldehyde, while within the ketone molecule the carbonyl group is found between two other carbon atoms.
The chemical formula for aldehydes is R-CHO, where R represents the rest of the molecule that is attached to the carbon of the aldehyde group through a single bond. Aldehydes are very common compounds and the simplest is formaldehyde. The chemical structure of formaldehyde is a single hydrogen atom that is bonded once to the carbon of the aldehyde group. It has the chemical formula CH 2 O.
The physical properties of aldehydes differ greatly due to the wide range of R groups attached to the -CHO group. It is the rest of the molecule that determines how the aldehyde will appear and act. Many different fragrances are aldehydes, and these molecules are also found in many essential oils. Examples include vanilla from the vanilla bean and cinnamaldehyde, which provides the scent and flavor of cinnamon.
Aldehydes can be formed by oxidation of an alcohol. During this chemical reaction, the alcohol loses a hydrogen atom to another molecule, in other words, it has dehydrogenated. The resulting molecule now has the -CHO group of an aldehyde at the end, instead of the -CH 2 OH group of an alcohol molecule. By adding water, an aldehyde can form an aldehyde hydrate, which is then oxidized to a carboxylic acid. These are common organic acids, such as acetic acid found in vinegar and formic acid produced by ants.
The type of alcohol that is oxidized determines the type of resulting molecule. To form aldehydes from alcohol oxidation, a primary alcohol is oxidized or a hydrogen atom is lost. Primary alcohols have only one R group attached to the -CH 2 OH group; there are also secondary and tertiary alcohols, with two and three R groups, respectively. When secondary alcohols are oxidized, ketones are formed. In contrast, tertiary alcohols cannot be oxidized.