Acetyl Chloride CAS 75-36-5

Acetyl Chloride – Essential Acetylating Agent and Organic Intermediate

Basic Information

• Product Name: Acetyl chloride (Ethanoyl chloride; Acetic acid chloride)

• CAS Number: 75-36-5

• Molecular Formula: C₂H₃ClO

• Molecular Weight: 78.50 g/mol

• Appearance: Colorless to pale yellow fuming liquid

• Boiling Point: 51–52°C

• Density: ~1.104 g/cm³

• Flash Point: 4°C (closed cup) – highly flammable

• Solubility: Reacts violently with water and alcohols; soluble in organic solvents (ether, chloroform, benzene)

• Stability: Stable under normal conditions, but reacts with moisture releasing HCl and acetic acid.

Overview
Acetyl chloride is a reactive acyl chloride derived from acetic acid. It is one of the most widely used acetylating agents in organic synthesis, serving as a key intermediate for the introduction of acetyl groups (CH₃CO–) into various substrates. Its high reactivity makes it indispensable in the production of pharmaceuticals, agrochemicals, dyes, and many specialty chemicals.

Applications

• Pharmaceuticals: Used in the synthesis of a wide range of drug substances, including acetylsalicylic acid (aspirin), N-phenylacetamide, acetazolamide, 2-acetylfuran, 2-acetylthiophene, 1,1'-diacetylferrocene, N-acetylthiourea, 1,4-naphthalenedicarboxylic acid, 2-acetyl-6-methoxynaphthalene, triphenylmethanol, 4-ethylbenzoic acid, acetylcholine chloride, bromadiolone, nabumetone, paracetamol, and ibuprofen.

• Agrochemicals: Precursor for pesticides, herbicides, and fungicides.

• Electroplating: Used in new electroplating formulations.

• Chelating agents: As a building block for complexing agents.

• Organic synthesis: Acetylation of amines, alcohols, phenols, and other nucleophiles in the production of fragrances, dyes, and polymers.

Reactivity and Handling
Acetyl chloride reacts violently with water, producing hydrogen chloride (HCl) gas and acetic acid. It also reacts with alcohols and amines, forming esters and amides, respectively. The reaction is exothermic and can be hazardous if not controlled. Handle under anhydrous conditions, in a well-ventilated fume hood, using appropriate personal protective equipment (gloves, safety goggles, flame‑resistant clothing).

Storage

• Store in a cool, dry, well‑ventilated area, away from moisture, heat, and incompatible materials (alkalis, oxidizing agents, water).

• Keep containers tightly sealed to prevent hydrolysis and vapor release.

• Store away from direct sunlight and sources of ignition.

• Shelf life: typically 12–24 months under proper storage conditions.

Packaging
Available in ISO tanks, 200 L steel drums, 200 L plastic drums, 200 L ultra-high-molecular-weight polyethylene drums, or custom packaging upon request.

Quality Assurance
Each batch is tested for purity (by GC), acid chloride content, and free acid to ensure consistent quality.