Chlorinated Hydrocarbons

Phosphonium nitrate ionic liquid catalysed electrophilic aromatic oxychlorination

“…Significantly, however, for xylene/P 8,8,8,1 NO 3 molar ratios of 2.0 and 4.0, the reaction proceeded to 72% and 43% conversions respectively, indicative of catalysis by P 8,8,8,1 NO 3 . In fact, the total moles of chloride that were converted per mole of P 8,8,8,1 NO 3 were greater than unity (1.8 and 2.0 respectively). Furthermore, dichloroxylenes were observed in all cases, up to 25% for the xylene/P 8,8,8,1 NO 3 molar ratio of 1 : 1.…”

“…Along with the recently reported trioctylmethylammonium (N 8,8,8,1 ) and -phosphonium (P 8,8,8,1 ), 12 butylisoquinolinium (BuisoQ) and butylmethylimidazolium (bmim) nitrate salts were also used ( Fig. 1).…”

“…The reaction mixture was constituted by HCl aq , anisole, and the IL, no other solvent being necessary. Using N 8,8,8,1 NO 3 as a nitrate source the conversion reached 90% with high selectivity (99%), but significant amounts of chlorooctane, deriving from IL breakdown, were formed (17%). BuisoQ and bmim nitrates behaved similarly to one another, and formed up to 5% of undesired products deriving from aromatic nitration.…”

“…In order to determine the optimal amount of nitrate ionic liquid, the electrophilic chlorination of p-xylene (less reactive than anisole) was conducted with varying substrate/P 8,8,8,1 NO 3 molar ratios of 0.5-1.0-2.0-4.0, using 2.0 equivalents of HCl at 80 • C (Fig. 3).…”

“…1 Aromatic chlorination is usually achieved via electrophilic substitution. For example, the industrial syntheses of chlorobenzene and chlorotoluene are still largely based on the textbook liquid-phase chlorination process with gaseous chlorine in the presence of a Lewis acid catalyst 2 (e.g.…”