An aldehyde is an organic compound containing the functional group. There are two main types of aldehydes:
Type 1: Single-carbon compounds always end in -al. Examples are formaldehyde, benzaldehyde, and acetaldehyde. They have strong, unpleasant odors and can cause irritation (mainly in the eyes) upon contact.
Aldehydes with multiple carbons tend to be more reactive than single-carbon compounds because they have an extra double bond meant to react with other chemicals or atoms. Examples are butyraldehyde and propionaldehyde.
Type 2: Compounds that end in -al can also end in -aldehyde. These usually have a pleasant smell or taste and can be found in fried foods, bread, and tobacco smoke. Most common aldehydes contain alcohol groups; for example, cinnamaldehyde, which has a cinnamon-like scent. A special class of aldehydes contains amine groups. Amines tend to be less reactive than alkyls: they don't necessarily undergo the same chemical reactions as alkyls but often participate in very similar reactions, such as nucleophilic addition and elimination reactions. Examples of these are glycine and acetylacetone.
Sometimes aldehydes are called "aldehydes" to distinguish them from other functional groups with a similar name, such as ketones, carboxylic acids, and phenols. Aldehydes and other functional groups are often named using suffixes to indicate their specific chemical structure. The prefix "aldehyde", however, is often used for any compound with the structure of an alkyl or phenol:
Aldehydes are a large and diverse class of compounds, found in natural products, cosmetically-scented products, many industrial products, and fuels such as gasoline. In nature, formaldehyde is produced by some bacteria and other microorganisms.
Aldehydes are also important in the biosynthesis of amino acids. Many aldehyde functional groups are present in biocatalytic pathways (such as the citric acid cycle). AZF is a DNA repair protein which is important in maintaining the fidelity of genomic DNA. The amino group can be used to react with nucleophilic reagents to form amides or imides.
Aldehydes are a chemical class of molecules found in the form of acids. These are organic compounds and they have a strong apple-like odor. The best way to identify an aldehyde is by reacting it with Fehling's solution, which will change color and precipitate out if the substance is an aldehyde. Aldehydes consist only of carbon, hydrogen, and oxygen atoms, thus making them organic molecules. There are three main ways to classify these molecules: primary (One carbon and two hydrogen atoms), secondary (Two carbons with two hydrogen atoms), or tertiary (Three carbons with one hydrogen atom).
Growing application areas
Aldehyde applications are not limited to the food industry. They also occur in areas such as: human-made flavors (such as perfumes), fragrances, natural flavorings, and pharmaceuticals. Aldehydes are derived from a set of chemicals that is called "ketones", which includes simple chemical compounds with a formula of C6H5C(O)R', where R' is an alkyl group. The most common and well-known aldehyde is formaldehyde, which occurs naturally in plants and animals. Formaldehyde has many different uses including preserving biological samples and creating certain types of glues.
Through formaldehyde, many other aldehydes and chemicals are created. These chemicals are used in industries such as: clothing, petroleum, cosmetics, pharmaceuticals and food. The main use of aldehydes is that they make up for part of flavors and fragrances in foods.
Structure and Stability of Aldehydes
Ketones are organic compounds made up of carbon and hydrogen with a formula of C6H5C(O)R'. Although there are many different types of ketones, there is only one simple type for the simplest ketone: propanone or acetone. Acetone has the chemical formula CH3COCH3.
The key difference between aldehydes and ketones is the presence of oxygen in carbonyl groups. This is also why aldehydes make up the main part of the aroma of most compounds which contain a carbonyl group.