第十一章羧酸和取代羧酸

1、RCOHORCOHOArCOHOCOHORRR HCOOHCH3COOHCH3(CH2)14COOHCH3(CH2)16COOHCOOHH3CCOOHOHOCOOHCH2CH2COOHCH2COOHCH2COOHCCHHCCOOHCH2COOHHOCH2COOHCOOHCOOHCOOHCOOHOHOH3CO CHCOOHCH2COOHH2N CH2(CH2)9COOHBr ( (末末端端) )n 羧酸的結(jié)構(gòu)及化學(xué)性質(zhì)分析羧酸的結(jié)構(gòu)及化學(xué)性質(zhì)分析H H有酸性有酸性羰基不飽和羰基不飽和, ,可加成、還原可加成、還原羰基羰基 a-Ha-H，有弱酸，有弱酸性，可取代性，可取代OH OH 可被取代可被取

2、代CHCOOHRH羧基可脫去羧基可脫去 COCO2 2R COOHArOHROH RCOOHB:RCOORCOORCOOCCO2HClClClCCO2HClHClCCO2HHHClCCO2HHHH RCO2H非酸性化合物+OHRCO2水水相相非非酸酸性性化化合合物物H+RCO2H有機相有有機機溶溶劑劑萃萃取取混混合合物物RCOOHRCOXRCOORCOORRCONH2(R)CRO1 1） 形成酰鹵形成酰鹵酰酰( (基基) )氯氯酰酰( (基基) )溴溴比較比較: : 醇類的鹵代醇類的鹵代 羧酸羥基的羧酸羥基的鹵代與醇類的鹵鹵代與醇類的鹵代有相似性代有相似性RCOOHRCOClSOCl2PCl3

3、PCl5RCOOHPBr3RCOBrROHSOCl2RClPBr3RBr H2ORHCCORCH2COOHRHCCOOCCH2ROHP2O5RCHCOOHRCH2COOCCH2RORHCCOHOCCH2ROHRCH2COOHRCH2COOCCH2ROP2O52+ + H2O加熱反應(yīng)即發(fā)生COOHCOOHOOOCOOHCOOHOOO+H2O+H2O RCOORRCOOHHOR H2O+H+RCOORRCOOHHOR- - H2OHRCOHOH親親核核加加成成RCOHOHHORRCOHOHORHRCOORRCOHOHHH2O+ + H3OHORH2OR- - H2ORRCOOHRCOOHRRCOO

4、RRCOORHHH2O+ + H3ORCOOH+RCOORRRCOOH+RCOOH3CCH3CCH2CCH3CH3CH3HCH3CH3CCH3RCOOHHRCOHOCCH3CH3CH3 HRCOHOCR2R1R3RCOOCR2R1R3RCOOCR2R1R3OH+H*( )RCOOHNH3RNH2RCOONH4RCONH2RCOONH3R- - H2ORCONHR100oC180190oC- - H2ORNH2RCONHRRCOClRCOOCRORCOOHSOCl2P2O5RCOOLiH2AlHRCOAlH2OHLiRCOH- - LiOAlH2RCOOHLiAlH4 H2LiH3AlHRCOA

5、lH3LiHHH2ORCH2OH3. 3. 羧酸的還原反應(yīng)羧酸的還原反應(yīng)n 用用 LiAlHLiAlH4 4 還原羧酸至醇還原羧酸至醇RCOOHLiAlH4RCH2OHH2O 羧基較難被還原羧基較難被還原 強還原劑可還原至強還原劑可還原至伯醇伯醇提示：提示：還原機理：還原機理：經(jīng)過中間體經(jīng)過中間體醛醛醛醛1 1o o醇醇RCH2OHRCOOHRCOOEt1. LiAlH4酯酯化化2. H2O1. LiAlH42. H2ORCH2NH2RCONH2RCRCOOHRCOClRCOOCRORCH2OHRCOORRCOH1. LiAlH4RCORLiAlH4RCHOHRNRCNRRCH2NHRLiAl

6、H42. H2O1. LiAlH42. H2ORCOOHAlH3B2H6RCH2OHH2OH2OCOOHB2H6O2NH2OCH2OHO2NRCOOH(1) NaOH(2)RHCO2+ ROHOORRRORRHCO2+ COOHRRCO2+H COOHCOOHCOOHCOOH+H2OO+CO2O +H2O+CO2 +X23 PX33 RCH2COOH+ PX3+ P(OH)3RCH2COXRHCCOHXH+XXRCH2COHXXRCHCOXXRCH2COOHRCHCOOHX- - HRCH2COX+烯烯醇醇化化交交換換2 PRCH2COX3RHCCOOHHX2 / P or SRHCCOOHX

7、X = Br , ClRCOHORCHOORCH2OHRCCH3OCCRHHR制備比 RX 多一碳的羧酸RMgXCO2(RCO2)2MgH2ORCO2HRXMgCOORMgXCOORMgXH2OCOHORRCNHH2O, H2OOHRCOOHHBrCH2CH2BrNCCH2CH2CNH2OH+HOOCCH2CH2COOHClCH2COONaNaCNNCCH2COONa(1) NaOH(2) H2O / H+HOOCCH2COOH2 NaCNC3H7CHOHCNC3H7CHOHCNH2O, HClC3H7CHOHCOOHHCN(NH4)2CO3C3H7CHNH2CNC3H7CHNH2COOHC3H7CHOH2O, HCl RCNH+H2ORCNHH2ORCNHHORCNH2HORCNH2H2OHORCNH2H2OHORCNH3HOORCONH3OHRCONH4HH+加加成成加加成成消消除除RCNHORCNOR