1-Butanesulfonyl chloride (CAS 2386-60-9) is a chemical compound that plays a critical role as an intermediate in various industrial syntheses. A thorough understanding of its chemical and physical properties is essential for its safe and effective use, particularly in sensitive applications like pharmaceutical and pesticide manufacturing. This section delves into its key characteristics.

Appearance and Physical State: At room temperature, 1-butanesulfonyl chloride typically appears as a clear, colorless to light yellow liquid. This visual characteristic is a primary indicator of its state and general purity. Its liquid form under standard conditions facilitates easier handling and measurement in synthesis processes.

Molecular Structure and Formula: The chemical formula for 1-butanesulfonyl chloride is C4H9ClO2S, with a molecular weight of approximately 156.63 g/mol. This structure, featuring a four-carbon chain attached to a sulfonyl chloride functional group, dictates its reactivity and its role as a chemical building block.

Reactivity and Stability: The sulfonyl chloride group (-SO2Cl) is highly reactive, particularly towards nucleophiles. 1-Butanesulfonyl chloride readily reacts with water, undergoing hydrolysis to produce butanesulfonic acid and corrosive hydrogen chloride (HCl) gas. This moisture sensitivity necessitates careful handling and storage in anhydrous conditions, typically under an inert atmosphere, to prevent degradation and hazardous reactions. It is also reactive with alcohols, amines, and other compounds containing active hydrogen atoms.

Key Physical Properties:

  • Melting Point: Reported as -29°C, indicating it remains liquid at typical laboratory temperatures.
  • Boiling Point: Approximately 80-81°C at 9 mmHg, suggesting it can be purified via vacuum distillation.
  • Density: Around 1.208 g/mL at 25°C, meaning it is denser than water.
  • Flash Point: Approximately 79.4°C (175°F), classifying it as a combustible liquid that requires appropriate fire safety measures.
  • Solubility: It decomposes in water but is generally soluble in common organic solvents like ether and benzene.

Safety and Handling: Due to its corrosive nature and potential to release toxic fumes (HCl) upon contact with moisture, 1-butanesulfonyl chloride must be handled with appropriate personal protective equipment (PPE), including gloves, eye protection, and respiratory protection in poorly ventilated areas. Storage should be in tightly sealed containers in a cool, dry, and well-ventilated place, away from incompatible materials such as water, strong bases, and oxidizing agents.

Understanding these properties is paramount for chemists and engineers involved in the synthesis and application of this important intermediate, ensuring both safety and process efficiency.