COOCH2CH3

COOCH2CH3 denotes the ethyl ester substituent, a common ester group in organic chemistry. When attached to a carbonyl, it takes the form R-COO-CH2CH3, i.e., an ester derived from ethanol and a carboxylic acid. A well-known example is ethyl acetate (CH3COOCH2CH3), the simplest ethyl ester of acetic acid.

Structure and general features: The ester group consists of a carbonyl carbon double-bonded to oxygen and single-bonded to an alkoxy oxygen bearing an ethyl group. This arrangement gives two relatively distinct regions: a polar carbonyl function and a nonpolar ethyl moiety. Ethyl esters typically exhibit moderate polarity, are prone to hydrolysis, and have comparatively low to moderate boiling points, making them useful as solvents in various applications. They are generally flammable and can be irritants.

Synthesis and reactivity: Ethyl esters form by esterifying carboxylic acids with ethanol in the presence of an acid catalyst (Fischer esterification). They can also be prepared via reaction of acyl chlorides with ethanol or through transesterification, where the alkyl group of an ester is exchanged with another alcohol. Esters undergo hydrolysis to yield the corresponding carboxylic acid and alcohol, under either acidic or basic (saponification) conditions. They can be reduced to primary alcohols with strong reducing agents, or undergo transesterification to swap the ethyl group for other alkyl groups.

Applications and safety: Ethyl esters, especially ethyl acetate, are widely used as solvents in paints, coatings, inks, adhesives, and cosmetics, and as intermediates in organic synthesis. They are generally considered low-to-moderate hazard solvents; handling requires ventilation and avoidance of prolonged inhalation or ignition sources due to flammability.