第十三章 羧酸及其衍生物 有机化学

第十三章羧酸及其衍生物COOH饱和一元脂肪酸通式：CnH2nO2（Ω=1）13.1羧酸的分类及命名与醛类似选择含有羧基的最长碳链为主链羧基编号为#1系统命名俗名甲酸蚁酸乙酸醋酸十八碳酸硬脂酸HCOOHCH3COOHCH3(CH2)16COOH系统命名PhCHCHCOOH反-3-苯基-2-丙烯酸HOCH2CH2CHCH2COOHCl5-羟基-3-氯戊酸BrCH2CHCCH2CH2COOHC2H54-乙基-6-溴-4-己烯酸CH3CH2CHCClOHO2-氯丁酸习惯命名CH3CH2CHCClOHO-氯丁酸CH3CH2CH2CHCH2COOHPh-苯基己酸含有脂环和芳环的羧酸命名环己基甲酸COOHCH(CH3)22-异丙基环戊基甲酸苯甲酸COHOCOOH二元羧酸命名HOOCCH2CHCH2CH2COOHBr3-溴己二酸HOOCCH2CH2COOH丁二酸HOOCCH-CHCOOHOHOHC=CHHHOOCCOOH2,3-二羟基丁酸酒石酸丁烯二酸马来酸羧酸去掉羟基后得到的基团称为酰基COCOCH3CORCOAr羧酸去掉氢后得到的基团称为酰氧基COOCOOCH313.2羧酸的制法工业制法NaOH+CONa+COO-HCOOH150℃,100PaH+CH2CH2O2,CuCl2CH3CHOO2,Co3+CH3COOHO2,Co3+,180℃,20atmCH3CH2CH2CH3CH3COOHO2,Rh3+,180℃,40atm,I2CH3OHCH3COOHCHORRCH2OHRCOHOK2Cr2O7+Cr3+K2Cr2O7H2SO4H2SO4实验室制法一、氧化法伯醇或醛的氧化RCOOHRCHO[O][O]RCH2OHCHORRCH2OHRCOHOΔKMnO4ΔKMnO4+MnO22个-H沉淀烯烃氧化RCHO①Ag2OorAg(NH3)2+OH-②H3O+RCOOHRCOOH+R'COOH(1)KMnO4/OH-,△RCHCHR'(2)H3O+RCOOH+R'COOHO3RCHCHR'H2O2烷基苯氧化烷烃氧化R(1)KMnO4/OH-,△(2)H3O+COOHOCH3CH2CH3OCH3COHOKMnO4△RCH2CH2R'[O]硬脂酸锰,120℃RCOOH+R'COOH二、水解法CR2H2O+NRCOHO+NH4+H2ORCORCY++HYOOHY=OR’,NH2,XH2ORCORCOR'++R'OHOOHH+orOH-H2ORCORCNH2++NH3OOHH+orOH-H2ORCORCO+OOHH+COR2三、Grignard试剂与CO2作用RMgBr+O=C=ORCOOMgBrH3O+RCOOHMgBrCOO+ROMgBrCOH+H2ORROHCOMgBrCOO+OMgBrCOH+H2OOHCOCO2+150~160℃H+H2OONaOHCOONaOHCOOH0.5MPaCO2+180~250℃H+H2OOKOHCOOK2.02MPaOHCOOHKolbe-Schmitt反应羧酸的制备RCHORCOHORCNRCH2OHCCRRHHRRRXRLiRMgXRCClORCOROHHRROHOHorCO2CrO3CrO3H2SO4KMnO4H2SO4KMnO4NaCN丙酮Rosenmund还原KMnO4LiorMgH2OH2OH2SO4H2SO4H2OorKMnO4R'KMnO4(苯基=R侧链=R’)ROHSOCl213.3羧酸的物理性质沸点分子间作用力,氢键都比结构与分子量相似的其他化合物强,bp(1atm)31℃80℃99℃OH141℃OHOO醋酸可形成分子间的双氢键熔点8个碳的饱和脂肪酸常温下为固体具有不饱和双键（尤其是顺式结构）的脂肪酸熔点较低，如以下各18碳酸:硬脂酸(饱和的):72C油酸(一个顺式双键):16C亚麻油酸(两个顺式双键):-5C水中的溶解度与醇在水中的溶解度相似可与水形成氢键H3CCOHOOHOHHH随碳链增长水溶性降低.4个碳以下的羧酸可与水混溶10个碳的羧酸不溶于水在醇中的溶解度比水中的大.在非极性溶剂（如氯仿）中也是可溶的，一般以二聚体形式溶解。13.4羧酸的化学性质羧酸的结构HCOHO120pm134pmRCOOHsp2RCOOHRCOOHRCOOHRCOOHRCOOH酸性烃基上的取代羰基碳的反应脱羧反应酸性醋酸醋酸根离子CROOCROOCROO诱导效应COOHOCH3COOHCOOHNO2COOHNO2COOHNO2p-methoxybenzoicacidm-nitrop-nitroo-nitropKa=4.46pKa=4.19pKa=3.47pKa=3.41pKa=2.16吸电子基团:强酸弱碱供电子基团:弱酸强碱CCOOXCCOHOX+H+各取代基诱导效应比较-NO2-CN-COOHFClBrI-COOR-OCH3-OHC6H5--CH=CH2H-CH3-C2H5-CH(CH3)2-C(CH3)3酸性增强CH3COHOCH2COHOO2NCH2COHOH2NCH2COHOHOpKa=4.753.832.341.68CH2COHOICH2COHOBrCH2COHOClCH2COHOF3.122.862.862.66COHOHCOHOCH3COHOCH3CH2COHOCH3CHCH3COHOCH3CCH3CH33.774.754.884.865.05羧酸衍生物的生成酰卤的生成+PCl33RCOCl+H3PO3△RCOOH3+SOCl2RCOCl+HCl+SO2△RCOOHH3CCOClH3CCOOH+PCl33+H3PO3△3+SOCl2+HCl+SO2COOHNO2COClNO2酸酐的生成△++H2ORCOOHCOHORP2O5RCORCOOCOOHCOOH230℃COCOO△++NaClRCOClCONaORRCORCOO混合酸酐酯的生成及酯化反应机理+RCOOHHOR'H+RCOOR'+H2OH+CH3COOH+CH3CH2OHCH3COOC2H5+H2O+RCOO-△R'CH2ClRCOOCH2R'+Cl-+RCOOHHOR'+RCOOHHOR'酯化反应机理（以O18为示踪剂）+RCOOHHOR'*RCOOR'*+H2OH+酸催化：羰基氧原子发生质子化RCOOHR'OH*RCOHOH*H+RCOHOHOR'HRCOHOH2*-H2OOR'RCOH*OR'-H+RCO*OR'叔醇的酯化生成酰胺+RCOOHHOCH++H2OR1R2R3RCOOCR1R2R3+H2ORCOOH+NH3RCONH2RCOONH4180~190℃COOHNH2+-H2OCONH84%羧基的还原LiAlH4(CH3)3CCOOH乙醇H2O(CH3)3CCH2OHCOOH1)LiAlH42)H2OH2PtCOOHCH2OH脱羧反应在结构上，两个吸电子基连在同一个碳上的化合物，热力学上不稳定，加热易脱去一小分子。△Cl3CCOOHCHCl3+CO2△COOHNO2O2NNO2NO2O2NNO2+CO2通常-碳上连有吸电子基的羧酸，加热容易脱羧。HOOCCH2COOHCH3COOH+CO2二元羧酸的热分解反应CH3COONa+NaOH(CaO)共熔△CH4+Na2CO3HOOCCOOH△HCOOH+CO2HOOCCH2COOH△CH3COOH+CO2CH2CH2COOHCH2CH2COOHBa(OH)2△CH2CH2CH2CH2CO+CO2+H2OCH2COOHCH2COOH300℃CH2CCH2CO+H2OOO电解羧酸钠：Kolbe合成法2RCOONa+H2O+2CO2+NaOH+H2RR电解阳极阴极RCOO-+e-RCOORCOOR+CO2RR2R2H2O+2e-OH-+H2阳极阴极-氢原子的反应TheHell-Volhard-ZelinskyReaction-H活性:羧酸小于醛酮。催化剂:PCl3、PBr3，红磷(P)等。+X2+HXRCHCOHOHRCHCOHOXPorPX3取代历程2P+3X22PX33RCH2COX+H3PO42RCH2COOH+PX3RCH2COX+X2RCHXCOX+HXRCHXCOOH+RCH2COXRCHXCOX+RCH2COOHExampleCH2COHOPCl3苯80℃(60-62%)+Br2BrCHCOHO应用CH3CH2CH2COHOBr2PCH3CH2CHCOHOBr(77%)CH3CH2CHCOHOOH(69%)H2O,加热K2CO3-氨基酸的合成(CH3)2CHCH2COHOBr2PCl3(CH3)2CHCHCOHOBr(CH3)2CHCHCOHONH2(88%)(48%)NH3,H2O13.5重要的羧酸（自学）13.6羧酸衍生物的命名经简单水解反应即可变为羧酸的一些化合物——羧酸衍生物如：酰卤、酸酐、酯、酰胺，腈RCOXRCOXRCOO(RCO)2OCORRCOORCOOR'R'RCONH2RCONH2RCNRCNOOOH3COHH3CHOH3CH2CHOOHCH3CH3CH3OOCH3OHCH3OCH3OCH3N(CH3)2HO红霉素AOOOHOHHCHOHOH2CVitaminCγ-内酰胺青霉素(penicillin)NHORR-C-NHONOSCH3CH3COOHR=C6H5CH2-(penicillinG)命名：酰卤CH3CClO甲酰氯3-丁烯酰氯OH2CCHCH2CClOCBrF对-氟代苯甲酰溴RCOX酸酐乙酸酐苯甲酸酐苯甲酸庚酸酐CH3COCCH3OOC6H5COCC6H5OOC6H5COC(CH2)5CH3OORCOOCOR酯CH3COCH2CH3O乙酸乙酯丙酸甲酯苯甲酸-2-氯乙醇酯OCH3CH2COCH3COCH2CH2ClORCOOR'酰胺CH3CNH2O乙酰胺3-甲基丁酰胺O(CH3)2CHCH2CNH2CNH2O苯甲酰胺RCONH2CH3CNHCH3ON-甲基乙酰胺N-甲基-N-异丙基丁酰胺CN(CH2CH3)2ON,N-二甲基苯甲酰胺OCH3CH2CH2CNCH(CH3)2CH3腈CH3CN乙腈C6H5CN苯甲腈NCCH3CHCH32-甲基丙腈RCN13.7羧酸衍生物的物理性质沸点熔点酰胺的熔点很高.酰胺分子中N-H键越多.熔点越高HCONCH3CH3CH3CONHCH3CH3CH2CONHHm.p.-61Cm.p.28Cm.p.79C溶解度酰卤和酸酐活性太强，在水中和醇中发生反应酯,叔胺和腈是很好的极性非质子性溶剂有机反应中常用溶剂:乙酸乙酯二甲基甲酰胺(DMF)乙腈CH3COCH2CH2CH2CH2CH2CH2CH2CH3OCH3CH2COCH2CHCH3OCH3CH3COCH2CH2CHCH3OCH3作为调味剂的酯类香蕉气味菠萝气味朗姆酒桔子味梨子气味苹果味乙酸异戊酯丁酸乙酯乙酸异丁酯乙酸正辛酯乙酸正丙酯丙酸甲酯CH3CH2CH2COCH2CH3OCH3COCH2CH2CH3OCH3CH2CH2COCH3O13.8羧酸衍生物的结构及化学性质RCH2CWORCHCWHO氧的碱性-H的活性羰基的活性离去基团酰基上的亲核取代水解OCRClOCOHR+H2OHCl+OCOHR+H2O+RCORCOORCHOOOCOHR+H2O+R'RCOOR'OHOCOHR+H2O+RCNH2ONH3Example皂化反应OCCH3ClOCOHCH3+HOHHCl+OCCH3OCH3OCOHCH3+HOH+CH3OHH+OCCH3(CH2)16CH2OCONaCH3(CH2)16+3HOH+NaOHCHCH2OCCH3(CH2)16OCCH3(CH2)16OOOCH2CHCH2HOHOHO3ExampleH2OOCCH3NHCH3OCOHCH3+HClCH3NH3+Cl-+H2OOCCH3NHCH3OCOCH3+OH-CH3NH2+H2O+OH-NH3+CNCNH2OO