有机化学英文课件：Chapter8 Ethers and epoxides

1、R-O-RC2H5-O-C2H5Diethyl etherDiethyl EtherCheck the “fine print”R-O-RO2R-O-O-RRCH-OROOHEXPLOSIVE 8.1.1 Structure, classification and nomenclatureCOC110。醚键1.18D general formula: R-O-R symmetrical ether 单 mixed ether 混 cyclic ether 环Nomenclature1.Names of alkyl (or aryl ) + ether(1) symmetrical ether

2、(2) Mixed ether: Alphabetically (3) Complicated ether: -OR alkoxy 环 醚环 氧 化 合 物大 环 多 醚(4) Cyclic ether( epoxide)CHCHCH3OH3C123CH2CHCH2CH3O1232, 3-Dimethyl oxirane2-Ethyl oxirane大环多醚 (OCH2CH2)n 冠醚（Crown ether）OOOOOO18-冠-6(18-Crown-6)OOOOOO二苯并-18-冠-6OOOOOO18-Crown-6K+X-8.1.2 8.1.2 Physical propertyPhys

3、ical property b.p.比同数碳原子的醇低得多。比同数碳原子的醇低得多。CH3OCH3 C2H5OC2H5b.p. 24.9 34.6C2H5OH CH3CH2CH2CH2OHb.p. 78.4 8.1.3 Chemical propertyChemical property Chemical property is stableChemical property is stable，often as often as solvent.solvent.COC bond could be broken under extreme condition.CORRH

4、H+CHORRH 1. Reaction with cold concentrated acids(formation of oxonium salt)： Cl-CH3CH2OCH2CH3+ClHCH3CH2OCH2CH3H+protonated ether ,unstable+Cl-CH3CH2OCH2CH3OH2CH3CH2OCH2CH3+OH3+Cl-H+ C O C不易断裂C O CH形成氧正离子后吸电子能力增强CO键更易断裂R O R + HXROH + RXReaction activity：2. Cleavage of ethers by hot acids (HI, HBr,

5、HCl).伯烷基醚按伯烷基醚按SN2机制断裂，机制断裂，叔烷基醚按叔烷基醚按SN1机制断裂，机制断裂，芳基烷基醚总是烷氧键断裂。芳基烷基醚总是烷氧键断裂。 CH3O CH3 HICH3OH + CH3IHICH3I机理(SN2)：CH3 O CH3+ H+CH3 O CH3HCH3 O CH3H+ ICH3OH + CH3I.伯烷基醚按伯烷基醚按SN2机制断裂，机制断裂，叔烷基醚按叔烷基醚按SN1机制断裂，机制断裂，芳基烷基醚总是烷氧键断裂。芳基烷基醚总是烷氧键断裂。 CH3O CH3 HICH3OH + CH3IHICH3I机理(SN2)：CH3 O CH3+ H+CH3 O CH3HCH3

6、 O CH3H+ ICH3OH + CH3ICH3 O C(CH3)3HICH3OH + (CH3)3CI机理(SN1):CH3 O C(CH3)3HIH+CH3 O C(CH3)3H(CH3)3C + CH3OHI（CH3)3CICH3IOCH357%HI120-130 COH + CH3I3. Formation of peroxide. hydrogen of -carbon CH3CH2O CHCH3HO2CH3CH2O CHCH3OOH检验：过氧化物FeSO4Fe2(SO4)3KSCNK3Fe(SCN)6红色除去：在蒸馏前，加入5FeSO4溶液EPOXIDESCCCCORCO3H中文

7、书：中文书：P458.28.2OHHOOOOOHOHOCCEpoxidesEpoxides-Reaction of Opening RingReaction of Opening Ring H2COCH2O CC 110。110。1.18D1.18D张力环能溶于水、乙醇、乙醚发生亲核取代，重要有机合成中间体H2COCH2 NuHOCH2CH2NuH+ H2COCH2H2O/H+ROH/H+HXHCNBH3NH3RMgXLiAlH4HOCH2CH2OHROCH2CH2OHXCH2CH2OHHOCH2CH2CN(CH3CH2O)3BNH2CH2CH2OHRCH2CH2OHCH3CH2OHRMgX

8、+ CH2CH2ORCH2CH2OHCH3ONa +CH2CH2OCH3OCH2CH2OH1. Acid catalyst: 亲核试剂进攻取代较多的环氧烷碳原子(SN1) (1)CH3CHOCH2Nu(2)HCH3CHOCH2H+CH3CH HOCH2Nu2. Base catalyst：亲核试剂进攻取代较少的环氧烷碳原子(SN2)(1)CH3CHOCH2Nu(2)CH3CHOCH2Nu(1)位阻较大 CH3CHOCH2Nu（2）CH3CH NuCH2OHH2ONu:RO、PhO、RMgXCCOHHCH3CH3CH3ONa +?CH3OHUnsymmetrical EpoxideCCOHHCH

9、3CH3CH3ONa +CH3OHBasicLeast HinderedCCOHHCH3CH3CH3OH+H+CCOHHCH3CH3H+CCOHHCH3CH3HCCOHHHCH3CH3CCOHHHCH3OCH3CH3Most Substituted8.3 冠醚的络合反应和相转移催化00.05腔体直径腔体直径12-C-415C518C621C7铵OOOOOO18-Crown-6Crown etherPhase-transfer agent冠醚与金属离子所形成的络合物可溶于低极性的有机溶剂，并且随带着负离子一起进入有机溶剂中。 OOOOOOKMnO4溶于苯

10、中。紫色苯冠醚与金属离子所形成的络合物可溶于低极性的有机溶剂，并且随带着负离子一起进入有机溶剂中。 OOOOOOKMnO4溶于苯中。紫色苯相转移催化剂 能使互不相溶的两相中的物质发生反应或加速反应的催化剂。CH3KMnO4, Benzene二环己基18冠6COOH100% 界面 传递CN传递Cl水相有机相OOOOOOKOOOOOOKCN ClKCl KCN OOOOOOKCN RCl OOOOOOKClRCN RX + KCNPTCRCN + KX8.4 Preparation of ether(醚的制备醚的制备) 1.醇的分子间脱水简单醚的制备 2.Willianmson合成法混合醚的制备2ROHH2SO4ROR + H2OHOCH2CH2CH2CH2OHH2SO4ORONa RORArONa ArOR+ RX不能用叔卤代烷，以减少消除；芳基烷基醚的合成总是用酚钠。 例1：合成CH3CH2OC(CH3)3解：(CH3)3CONa + CH3CH2Br C2H5OC(CH3)3不能用C2H5ONa和(CH3)3CBr,因为此时以消除反应为主。CH3 CCH3 CH3BrC2H5ONaCH3 CCH3 CH2