Facile, efficient, and environmentally friendly α- and aromatic regioselective chlorination of toluene using KHSO5 and KCl under catalyst-free conditions. (16th March 2015)

• Record Type: Journal Article
• Authors: Çimen, Yasemin; Akyüz, Seçkin; Türk, Hayrettin
• Is Part Of: New journal of chemistry. Volume 39:Number 5(2015:May)
• Page Start: 3894
• Page End: 3899
• Publication Date: 2015-03-16
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c5nj00118h
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The nontoxic, green, safe, stable, and inexpensive reagents Oxone and KCl were employed in the non-catalyzed chlorination of toluene at room temperature. Abstract : Toluene was subjected to room-temperature chlorination with the KHSO5 –KCl system in organic solvent–water mixtures. In a typical reaction, the amounts of toluene, KHSO5, and KCl were 1.0, 5.0 and 7.5 millimoles, respectively. The reaction mixtures, consisting of an organic solvent (2.50 mL) and water (1.50 mL), were rather multiphase like slurry. Depending on the nature of the organic solvent present in the solvent mixtures, either α-chlorination or aromatic chlorination of toluene was favoured. The chlorinated solvents CH2 Cl2, CHCl3, and CCl4 favoured the α-chlorination, yielding >81% benzyl chloride selectivity in 38–59% toluene conversions in 1 hour. The water miscible polar solvents C2 H5 OH, CH3 OH, and CH3 CN favoured the aromatic chlorination, yielding 61–86% chlorotoluene selectivity in >98% toluene conversions in 1 hour. Reactions carried out in all solvent mixtures yielded only chlorinated toluene products. The method presented here for the regioselective chlorination of toluene meets the goals of green chemistry as well in a number of ways: (a) catalyst-free conditions; (b) nontoxic, green, safe, stable, and inexpensive reagents; (c) low environmental impact; (d) no heating or cooling; (e) simple and cheap operation; and (f) high regioselectivity.