ch3-choh-cooh+hohc(ch3)cooh=====ch3-choh-coohc(ch3)cooh 链状 ch3-choh-cooh====ch3-ch-c=o +h2o 只能打成这样了 ---o 2ch3-choh-cooh====ch3chcoochch3+2h2o -ooc- nhohc(ch3)cooh=====h[-ohc(ch3)co-]oh+(n-1)h2o 说明一下：乳酸即二位羟基丙酸 三元环中第二行的氧原子连在第二三个碳上 六元环中coo和ooc并列，两边都是ch3ch
