CH3CHClCH2CH3

CH3CHClCH2CH3 is an organochlorine compound with four carbon atoms. It is most commonly referred to as 2-chlorobutane, or butan-2-yl chloride (systematic IUPAC name). Its molecular formula is C4H9Cl and the molecular weight is about 92.6 g/mol. The structure features a chlorine substituent on the second carbon of a four-carbon chain (CH3-CHCl-CH2-CH3). Its SMILES notation is CC(Cl)CC.

This compound is a colorless liquid at room temperature with a boiling point around 68–69 °C and a density near 0.87 g/mL. It is poorly soluble in water and more miscible with organic solvents. It is flammable and should be handled under appropriate safety conditions.

Production and applications: 2-Chlorobutane is typically prepared by chlorinating butane under radical conditions or by converting butan-2-ol with hydrogen chloride (sometimes via Lewis acid-catalyzed dehydration). It serves as an alkylating agent and synthetic intermediate in organic synthesis, used to prepare other halides, alcohols, and various chemical intermediates in the pharmaceutical, agrochemical, and materials sectors. Its secondary alkyl chloride structure makes it susceptible to nucleophilic substitution and elimination reactions.

Reactivity: In nucleophilic substitution, 2-chlorobutane reacts with nucleophiles to yield corresponding secondary alcohols (e.g., with aqueous potassium hydroxide to give 2-butanol) or other substituted products. In elimination, base-induced dehydrohalogenation yields 2-butene mixtures. The compound also participates in Finkelstein-type reactions (e.g., with iodide salts) to form 2-iodobutane.

Safety and handling: 2-Chlorobutane is a hazardous chemical that can irritate skin, eyes and the respiratory tract. It is moderately toxic if inhaled or absorbed through the skin. It is flammable and should be stored away from ignition sources in a well-ventilated area, using appropriate personal protective equipment. Spills should be contained to prevent environmental release.