Aldehydes result from the first oxidation of alcohols and have the general structural formula . Since aldehydes cannot form hydrogen bonds between themselves, they have lower boiling points than corresponding alcohols or acids. Again, as with the other classes or organic compounds in table 3-3, the lowermolecular-weight aldehydes (up to five carbons) are soluble in water. Aldehydes are neutral in pH and undergo both oxidation and reduction reactions. They are easily oxidized to acids and reduced to alcohols. Some aldehydes, such as vanillin and benzaldehyde, are frequently used in the pharmacy as flavoring agents.
Others, such as formaldehyde, are often used as disinfectants.