大连理工大学有机化学11 羧酸

Chapter11第11章羧酸及其衍生物Chapter1111.1羧酸及其衍生物的分类及结构11.2羧酸及其衍生物的物理性质11.3羧酸的化学性质11.4羧酸衍生物的化学性质11.5羟基酸和羰基酸11.6碳酸及其衍生物Chapter1111.1羧酸及其衍生物的分类及结构11.1.1羧酸的结构和分类11.1.2羧酸衍生物的结构和分类Chapter11''''-羧酸R-COOH官能团-COOH羧酸衍生物RCOYY=F,Cl,Br,I,OR,RCOO,NH2,NHR,NR2Chapter1111.1.1羧酸的结构和分类(1)按碳架分类和结构开链脂肪酸甲酸醋酸月桂酸硬脂酸脂环酸环戊基甲酸环己基甲酸3-甲基环戊基甲酸芳酸苯甲酸苯乙酸β-萘甲酸COOHCOOHCH3COOHHCOOHCH3COOHCH3(CH2)10COOHCH3(CH2)16COOHCOOHCOOHCH2COOH1.分类Chapter11不饱和酸丙烯酸2-丁烯酸肉桂酸2-环己烯基甲酸CH2CHCOOHCH3CHCHCOOHCHCHCOOHCOOH(2)按-COOH数目分类一元酸丙酸甲基丙烯肉桂酸CH3CH2COOHH2CCHCOOHCHCHCOOHCH3Chapter11二元酸乙二酸（草酸）丙二酸己二酸顺丁烯二酸反丁烯二酸（马来酸）（富马酸）对苯二甲酸邻苯二甲酸HOOCCOOHHOOCCH2COOHHOOC(CH2)4COOHHHHOOCCOOHHHCOOHHOOCHOOCCOOHCOOHCOOHChapter11三元酸偏苯三甲酸均苯三甲酸四元酸•均苯四甲酸2,3-二羧基-1,4-丁二酸乙二胺四乙酸（EDTA）COOHCOOHCOOHCOOHHOOCCOOHHOOCCOOHCOOHHOOC(HOOC)2CHCH(COOH)2(HOOCCH2)2NCH2CH2N(CH2COOH)2Chapter11取代羧酸乳酸苹果酸柠檬酸水杨酸没食子酸乙醛酸乙酰乙酸3-苯基-2-氨基丙酸-戊酮酸三氟乙酸OHCOOHOHOHOHCOOHOHCCOOHCH3COCH2COOHCHOHCH3COOHCHOHHOOCCH2COOHOHCCH2COOHHOOCCH2COOHCH2CHNH2COOHCH3COCH2CH2COOHF3CCOOHChapter112.羧酸的结构1200~CH2HCOHO0.1520.1250.131..........C=OC=O-COOH中C为sp2与-OHp-π共轭与α-Hσ-π共轭两种交叉共轭乙酸COHH乙醛0.1500.120HCOH3甲醇0.143Chapter11Csp2上正电荷下降，亲核加成比醛、酮难；C—OH变短，—OH被亲核取代活性比醇小；O—H变长，H的酸性比醇强；C—COOH间极性小,α-H的活性比醛、酮小。两种交叉共轭：电子密度平均化，键长平均化乙酸的分子模型Chapter11苯甲酸苯甲酸分子模型-COOH：p-π共轭环-COOH：π-π共轭邻甲基苯甲酸邻甲基苯甲酸分子模型（非共轭体系）-COOH,在两个平面里COOH........COOHCHHHCH3Chapter11α,β-不饱和酸α,β-不饱和酸的分子模型（交叉共轭）羧酸根羧酸根分子模型（共轭）CCCH3COHO........COO-21e21eChapter1111.1.2羧酸衍生物的结构和分类羧酸分子的羟基被、、和(或、)取代分别称为酰卤、酸酐、酯和酰胺，统称为羧酸衍生物。羧酸衍生物分子中都有酰基羧酸衍生物的分类与羧酸的分类相同。CROX(X=F,Br,Cl)OCOR'OR'NH2NHR'NRR231.分类Chapter11酰卤的卤原子是F、Cl、Br，常用的是酰氯和酰溴：乙酰溴氯代乙酰氯苯甲酰溴对苯二甲酰氯酸酐分为同酸酐、混酸酐和内酸酐：(CHCHC)OO322CO(O)2COOCCHO3丙酸酐(同酸酐)苯甲酸酐(同酸酐)乙酸苯甲酸酐(混酸酐)HCBrO3CClOCHCl2COBrCOClCClOChapter11COCOOOOO邻苯二甲酸酐(内酸酐)顺丁烯二酸酐(内酸酐)基于烃氧基连接分式分为：乙酸乙酯乙酸苯酯d-戊內酯丙酸交酯COOCH325OHCCO3OOOOOOHCCH33CHChapter11酰胺分为氨基取代酰胺、内酰胺、亚酰胺和脚酰胺等CNHO2CNHO2CHNO2苯甲酰胺对苯二甲酰胺N-甲基乙酰胺N,N-二甲基甲酰胺(DMNF)顺丁烯二酰亚胺CNHCOONHO邻苯二酰亚胺d-戊內酰胺HCCONHCH33CHN(CH)O32NHOOChapter112.羧酸衍生物的结构羧酸衍生物CRXOOCCOORROCORRCRNHR'O与酰基连接的原子都是电负性元素，都有未用电子对。FClBrONCXOOCOCNO极性键p-π共轭体系CRXOOCCOORROCORRCRNHR'O键极性增大共轭效应增强Chapter1111.2羧酸及其衍生物的物理性质11.2.1羧酸的物理性质11.2.2羧酸衍生物的物理性质Chapter1111.2.1羧酸的物理性质C0~2—COOH挥发性液体，刺激性气味C3~8—COOH腐败味液体C9—COOH石蜡状固体HOOC-R-COOH晶体COOH1.一般物理性质Chapter11双分子缔合沸点、熔点大水中溶解度大与烷烃相似，偶数C羧酸的熔点比奇数的高。CH3COHOHOCOCH3CH3COHOHOCCH3OHOHChapter11常见的正构一元饱和脂肪酸的物理常数Chapter111H-NMR谱：—COO—H10～13α-H2.2～2.5IR谱：—COO—H2500~3300cm-1分子间缔合宽、强峰—COO—H3550cm-1(伸)925cm-1(弯)的变化如下页表C=O2.光波谱性质Chapter1111.2.2羧酸衍生物的物理性质沸点、水中溶解度与醛、酮相近分子间氢键，沸点、熔点高与H2O形成氢键，溶解度大RCXOROROORCOR'ORCONH2..1.一般物理性质Chapter11常见酰氯的熔点和沸点常见酯的熔点和沸点5280102120197247150～152(15mmHg)-112-94-98-110-14275CH3COClCH3CH2COClCH3(CH2)2COClCH3(CH2)3COClC6H5COClp-BrC6H4COClp-O2NC6H4COCl沸点/oC熔点/oC化合物77102126213100213-84-92-77-35-50-84CH3CO2C2H5CH3CO2C3H7-nCH3CO2C4H9-nCH3CO2C6H5C6H5CO2C2H5沸点/oC熔点/oC化合物CH2CCO2CH3CH3Chapter11常见酸酐的熔点和沸点常见酰胺的熔点与沸点140169198228284(升华)261202-73-45-75-5613121060(CH3CO)2O(CH3CH2CO)2O(CH3CH2CH2CO)2O[CH3(CH2)4CO]2O沸点/oC熔点/oC化合物HCCOOCHCOCCOOOH2CCOOCH2CO200(分解)221213216204166290288—3827911628-20130125238HCONH2CH3CONH2CH3CH2CONH2CH3(CH)2CONH2CH3CONHCH3CH3CON(CH3)2C6H5CONH2沸点/oC熔点/oC化合物CCNHOOH2CCNHOCH2COChapter11羧酸及其衍生物羰基的红外吸收ArCOOR1715~1730'RCONR21630~1690RCO21550~1630RCOOR1735~1750RCOCl(Ar)1780~18501690~1715Ar—CO2H1680~17001800~1850及1740~17901780~1860及1730~1780吸收波数/cm-1RCO2H1700~1725吸收波数/cm-1化合物化合物''-CCCO2HRCO()2OArCO()2O2.光波谱Chapter1111.3羧酸的化学性质11.3.1酸性11.3.2羧酸衍生物的生成11.3.3还原反应11.3.4脱羧反应11.3.5α-H的卤代反应Chapter111.羧酸化学性质概述12453RCHHHCOO还原亲核加成酸性衍生物脱羧取代11.3.1酸性Chapter11pKa=3～5与NaOH、Na2CO3、NaHCO3成盐分离、提纯、回收RCOOHRCOHORCOOOH2H3O++-+e12COOe12RCOOHNaHCO3RCOONaCO2OH2RCOONaRCOOHClHNaCl+++++2.酸性Chapter11(1)酸性大小判断可用I效应、C效应、空间效应判断酸性大小HCOOHCH3COOH-CH3供电子基+I效应前者-C效应COOHCH2COOHpKa1=2.85-COOH-I效应pKa2=5.70-COO+I效应氢键作用pKa1=3.03-COOH-C效应pKa2=4.54-COO+C效应CH2COOHCOOH--CHCHHOOCCOOH4.435.414.215.642.855.701.274.27pKa1pKa2HO2C-(CH2)4-CO2HHO2C-CH2CH2-CO2HHO2C-CH2-CO2HHO2C-CO2HChapter11取代苯甲酸（Y-C6H4-COOH）的pKa(25C。)4.174.384.354.143.973.974.023.553.664.574.474.213.423.514.824.174.274.273.863.833.813.853.643.774.084.094.143.493.544.604.173.913.793.272.922.852.863.44—2.984.093.462.212.895.41HCH3C2H5FClBrICNCF3OHOCH3C6H5NO2COOHpKa1pKa2pmoY---Chapter11(2)邻位效应基团的电子效应pKa1(2.89)pKa2(5.41)场效应-COO-的电子通过邻位效应空间作用分散到-NO2pKa=2.21立体效应破坏共轭，失去+C效应pKa=3.91氢键作用pKa=2.89CH3COOHCOONO2COOHCOOHCOOOH--YCOOHH+H+H+Chapter11COOCOOHCH2场效应诱导效应pKa1pKa2GCOOHG=HpKa=6.04G=ClpKa=6.25(3)场效应CCCOOHXdd诱导效应场效应的酸性比间位、对位的小Chapter11pKa4.574.474.384.173.91+C效应+C效应+C效应邻位效应pKa3.973.553.513.42-C效应-C效应-C效应-C效应COOHBrCOOHCNCOOHCOOHCOOHNO2OHCOOHCOOHOMeCH3COOHHCOOHCH3COOH(4)比较取代苯甲酸的酸性Chapter1111.3.2羧酸衍生物的生成1.酰卤的生成(用无机酰卤PCl3、PCl5、SOCl2卤化)RCYOY=,RCOO,(RO,NH2)X..-''-RCOOHPCl3RCClOP(OH)3++CH3COOHPCl3CH3COClH3PO3++沸点/OC1187552200制备低碳酰氯；易蒸馏出产物Chapter11制备高碳与芳酰氯；易分离出OPCl3RCOOHPCl5RCOClOPCl3ClH+++RCOOHSOCl2RCOClClHSO2+++生成的气体HCl、SO2易分离，HCl、SO2需吸收；OSCl2需过量Chapter112.酸酐的生成用P2O5、(CH3CO)2O脱水；蒸出H2ORCOHORCOHORCOORCOCH3COHOCH3COOCH3COCCOHOHOOCCOOOP2O5H2OCH2=C=O+++H2OChapter113.酯的生成（两种机理）用同位素跟踪方法研究反应机理证明醇中的氧进入产物酯中RCOHORCOORH++H-O-R18H2O''18+机理：亲核加成-消除1RCOHO23RCOHOHOHRHH+RCOOHHOR..+++''4