ONa OH OH COOH 150℃ C02 atm salicylic acid OH COOH COOH O-C-CH3 +(CH3CO)20-> (Asprine) COOK COOH OH OH KHCO3 OH +C02 H+ 3Mpa△ NH2 NH2 NH2 para-amono-salicylic acid ONa + CO2 150 o C atm OH COO - H + OH COOH OH COOH + (CH3CO) 2O COOH O-C-CH3 O (Asprine) OH NH2 + CO2 KHCO3 3Mpa COOK OH NH2 H + COOH NH2 OH para-amono-salicylic acid salicylic acid