RC++ RCOOH RC-O-COR RC-O-COR 2、酰卤的形成: RCOOH +PX RCOX+POX RCOOH+PX3 RCOX+H PO4 RCOOH +SOCI RCOX+SO2↑+HCl↑R3C++ R'COOH R3C–O –COR ' R3C–O –COR ' SN1 –H+ 2、 酰卤 的形成： RCOOH +PX5 RCOOH +PX3 RCOOH +SOCl2 RCOX+POX3 RCOX+H3PO4 RCOX+SO2 ￪ +HCl￪