Carboxylic acid
Polar organic acids with carboxyl group, widely occurring in nature.
Carboxylic acids are polar organic acids containing a carboxyl group (−C(=O)−OH) attached to an R-group, with the general formula R−COOH or R−CO2H. They occur widely in nature, with important examples including amino acids and fatty acids, and are used in the production of polymers, pharmaceuticals, solvents, and food additives.
- field
- Organic chemistry
- known_for
- Polar organic acids with carboxyl group; weak acids that partially dissociate in water; form carboxylate anions upon deprotonation
Lore & Background
Carboxylic acids are commonly identified by trivial names with the suffix -ic acid, while IUPAC-recommended names use the -oic acid suffix. For example, butyric acid is butanoic acid by IUPAC guidelines. The carboxylate anion is named with the suffix -ate, such as acetate from acetic acid. Carbonic acid, despite having a COOH-like moiety, is not generally classed as a carboxylic acid. Carboxylic acids are polar and participate in hydrogen bonding as both acceptors and donors. Smaller carboxylic acids (1 to 5 carbons) are soluble in water, while longer-chain acids have limited solubility due to hydrophobic alkyl chains. They tend to form dimers in nonpolar media and have higher boiling points than water due to hydrogen-bonded dimers. Carboxylic acids are Brønsted–Lowry acids and typically weak acids, partially dissociating in water. Electron-withdrawing substituents increase acidity, while electron-donating substituents decrease it. Deprotonation yields resonance-stabilized carboxylate anions.
Reader's Guide
Carboxylic acids are fundamental in organic chemistry and biochemistry. They are the most common type of organic acid and serve as building blocks for amino acids, fatty acids, and many industrial compounds. Their acidity, influenced by substituents, is key to their reactivity. Industrially, they are produced via carbonylation, oxidation, hydrolysis, and fermentation, and are used in polymers, pharmaceuticals, solvents, and food additives. Important examples include acetic acid (vinegar), citric acid (flavor and preservative), and fatty acids (soaps). The carboxylate salts, such as soaps, are widely used. Carboxylic acids also play a central role in biological processes, including the carbon-fixation step in photosynthesis catalyzed by RuBisCo. Their characterization via spectroscopy and their tendency to form dimers are notable physical properties. Overall, carboxylic acids are essential to both natural and industrial chemistry.
Did You Know?
- Carboxylic acids are often considered weak acids as they only partially ionise in water.
- Smaller carboxylic acids (1 to 5 carbons) are soluble in water, whereas bigger carboxylic acids have limited solubility.
- Carboxylic acids usually exist as dimers in nonpolar media due to their tendency to 'self-associate'.
- The conjugate base of acetic acid is acetate.
Frequently Asked Questions
Who is Carboxylic acid?
Carboxylic acid is a polar organic molecule defined by its carboxyl group—a carbon double-bonded to one oxygen and single-bonded to a hydroxyl—tethered to an R-group (R–COOH). It belongs to the organic chemistry field and is one of the most recognizable functional groups in the molecular universe.
What are Carboxylic acid's powers and role?
As a weak acid, it only partially releases its proton in water, yielding a carboxylate anion (R–COO⁻) upon deprotonation. That reversible dissociation lets it serve as a versatile building block in polymers, pharmaceuticals, solvents, and food additives.
How does Carboxylic acid's story end?
Its most common 'ending' is deprotonation, where it sheds its acidic hydrogen to become a carboxylate salt. Beyond that, it can be converted into esters, amides, or acyl halides, effectively transforming into a new character in the reaction narrative.
Why is Carboxylic acid so important?
It forms the structural backbone of amino acids and fatty acids, meaning virtually every living organism depends on it. Industrially, it feeds into the production of plastics, drugs, and flavoring agents, making it a load-bearing pillar of both biology and manufacturing.
Who does Carboxylic acid team up with most often?
Its most frequent partners are alcohols (forming esters) and amines (forming amides) through classic condensation reactions. In biological systems, it also pairs with amino groups to link amino acids into proteins.
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