2-Chloropropionic acid

Physical Properties

• Appearance: Colorless liquid.
• Odor: Possesses a distinct, irritating, and pungent odor.
• Melting Point: Approximately -30 °C.
• Boiling Point: Around 186–188 °C at standard atmospheric pressure.
• Density: ~1.23 g/cm³ at room temperature (heavier than water).
• Solubility: Highly soluble in water, ethanol, and diethyl ether.
• Flammability: Combustible, though it does not easily ignite under normal conditions. When exposed to fire or high heat, it decomposes and releases toxic and corrosive fumes, including hydrogen chloride (HCl) gas.

Chemical Properties

• Acidity & Reactivity: It is a strong organic acid and an alpha-halo carboxylic acid. The presence of the highly electronegative chlorine atom on the alpha-carbon significantly increases its acidity compared to propionic acid.
• Corrosiveness: Due to its acidic nature, it is highly corrosive and can cause severe skin burns and eye damage. It readily reacts with metals to release flammable hydrogen gas.
• Reactivity as an Intermediate: The carbon-chlorine bond makes it highly reactive towards nucleophilic substitution reactions. It readily reacts with bases, amines, and alcohols to form various derivatives such as esters, amides, and substituted acids.
• Stability & Hazards: It is stable under normal conditions but must be stored away from strong oxidizing agents and strong bases. Exposure to moisture can accelerate corrosion of metals. Strict personal protective equipment (PPE), including acid-resistant gloves and safety goggles, is mandatory when handling this substance.

Main Applications

• Pharmaceutical Synthesis: This is its most prominent use. It serves as a crucial intermediate in the synthesis of active pharmaceutical ingredients (APIs), particularly for producing non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen.
• Agrochemical Manufacturing: Widely utilized as a building block in the production of herbicides, fungicides, and plant growth regulators.
• Organic Synthesis Intermediate: Employed extensively in fine chemical manufacturing to synthesize other complex organic compounds, including amino acids (such as alanine derivatives) through ammonolysis.
• Polymer & Resin Modifiers: Used as a cross-linking agent or modifier in the production of specialized polymers, resins, and plasticizers to enhance material performance and durability.