如: CHCHCOOCH CH,-CH-COOCH Na ChOH CH CH2 CHCOOC2H5 甲苯 CH2-C-OC2H5 H CH-CH-COoCH COOH HO -C2HSOH CH2 CH-C=O △ O CO如： CH2CH2COOC2H5 CH2COOC2H5 CH2 CH2 – CH–COOC2H5 CH2 – C–OC2H5 CH2 O – Na,C2H5OH 甲苯 CH2 – CH–COOC2H5 CH2 – C=O CH2 –C2H5OH H+ H2O H+ COOH – CO2 Δ O = O