Abstract

Aldehydes are carbonyl-containing organic compounds of the general formula RCHO. The group R represents an aliphatic, aromatic, heterosubstituted radical, except in formaldehyde, where R represents hydrogen. Aldehydes are inherently reactive compounds. The carbonyl group is susceptible to both oxidation and reduction, yielding acids and alcohols, respectively. The common method of naming aldehydes corresponds very closely to that of the related acids in that the term aldehyde is added to the base name of the acid. The C₁ and C₂ carbon aliphatic aldehydes, formaldehyde and acetaldehyde, are gases at ambient conditions whereas the C₃ (propanal) through C₁₁ (undecanal) aldehydes are liquids, and higher aldehydes are solids at room temperature. The lower, C₁ to C₈ aldehydes have pungent, penetrating, unpleasant odors. Above C₈, aldehydes have more pleasant odors and some higher aldehydes are used in the perfume and flavoring industries. Reactions of aldehydes generally fall into two classes: those directly affecting the carbonyl group and those involving the adjacent carbon atom. There are, acute effects of aldehydes: eye, skin, and respiratory tract irritation, as well as organ pathology. Aldehydes find the most widespread use as chemical intermediates. A large proportion of aldehydes are converted to alcohols for use as solvents and in the manufacture of plasticizers. Fatty aldehydes C₈ to C₁₃ are used in nearly all perfume types and aromas.