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Conversion of Alcohols to Alkyl Chlorides Using the Bichloride Ionic Liquid [NEt 3 Me][Cl(HCl) n ]

Year: 2026

Type: article

Abstract: The solvent‐free chlorination of alcohols using the bichloride‐based ionic liquid [NEt 3 Me][Cl(HCl) 1.61 ] as a hydrogen chloride source is reported. In the presence of a catalytic amount of a carboxylic acid, a variety of alcohols undergo efficient chlorination under mild batch conditions. This method eliminates the need to handle hydrogen chloride gas. Benzyl and secondary alcohols are converted with good to excellent yields, whereas primary aliphatic substrates show moderate reactivity. Notably, short‐chain diol substrates primarily yield monochlorinated products, indicating some chemoselectivity under the reaction conditions. Tests for functional group compatibility reveal that ester groups stay intact, while acetals and simple alkyl ethers are cleaved in the strongly acidic environment. The ionic liquid can be recharged with hydrogen chloride and reused in subsequent reactions. Process robustness is demonstrated by gram‐scale reactions and straightforward product isolation via distillation or phase separation.

Source: European Journal of Organic Chemistry

DOI: 10.1002/ejoc.70780