RCHO

RCHO is a general shorthand used in organic chemistry to denote an aldehyde in which the formyl group is attached to an R group. In this notation, R represents any alkyl, aryl, or other substituent; the carbonyl carbon is at the end of the carbon chain, giving the structure R-CHO. Aldehydes are a class of carbonyl compounds characterized by this terminal carbonyl group and their typical reactivity in nucleophilic addition and oxidation-reduction processes.

Common examples include formaldehyde (R = H, H-CHO), acetaldehyde (R = CH3, CH3-CHO), and benzaldehyde (R = C6H5, C6H5-CHO). These compounds are versatile intermediates in organic synthesis and serve as precursors to a wide range of products, from resins and solvents to flavors and fragrances.

Key reactions involve the aldehyde carbonyl group. Aldehydes undergo oxidation to carboxylic acids and reduction to primary alcohols. They participate in nucleophilic addition reactions, such as with Grignard reagents to yield secondary alcohols after hydrolysis; reaction with alcohols in the presence of acid forms acetals. Aldehydes can also be introduced into carbon–carbon bond-forming processes, such as aldol condensations.

Preparation and occurrence: industrially, aldehydes are produced by oxidation of primary alcohols or, in the case of many higher aldehydes, via hydroformylation of alkenes. Formaldehyde is often produced from methanol. Aldehydes occupy important roles in manufacturing, including polymer precursors, fragrances, and flavor compounds, as well as serving as versatile intermediates in organic synthesis.

Safety: low-molecular-weight aldehydes can be irritants and, in some cases (notably formaldehyde), toxic or carcinogenic, necessitating appropriate handling, ventilation, and exposure limits.