有機(jī)化學(xué)英文課件：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。醚鍵1.18D general formula: R-O-R symmetrical ether 單 mixed ether 混 cyclic ether 環(huán)Nomenclature1.Names of alkyl (or aryl ) + ether(1) symmetrical ether

2、(2) Mixed ether: Alphabetically (3) Complicated ether: -OR alkoxy 環(huán) 醚環(huán) 氧 化 合 物大 環(huán) 多 醚(4) Cyclic ether( epoxide)CHCHCH3OH3C123CH2CHCH2CH3O1232, 3-Dimethyl oxirane2-Ethyl oxirane大環(huán)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.比同數(shù)碳原子的醇低得多。比同數(shù)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不易斷裂C O CH形成氧正離子后吸電子能力增強(qiáng)CO鍵更易斷裂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機(jī)制斷裂，機(jī)制斷裂，叔烷基醚按叔烷基醚按SN1機(jī)制斷裂，機(jī)制斷裂，芳基烷基醚總是烷氧鍵斷裂。芳基烷基醚總是烷氧鍵斷裂。 CH3O CH3 HICH3OH + CH3IHICH3I機(jī)理(SN2)：CH3 O CH3+ H+CH3 O CH3HCH3 O CH3H+ ICH3OH + CH3I.伯烷基醚按伯烷基醚按SN2機(jī)制斷裂，機(jī)制斷裂，叔烷基醚按叔烷基醚按SN1機(jī)制斷裂，機(jī)制斷裂，芳基烷基醚總是烷氧鍵斷裂。芳基烷基醚總是烷氧鍵斷裂。 CH3O CH3 HICH3OH + CH3IHICH3I機(jī)理(SN2)：CH3 O CH3+ H+CH3 O CH3HCH3

6、 O CH3H+ ICH3OH + CH3ICH3 O C(CH3)3HICH3OH + (CH3)3CI機(jī)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檢驗：過氧化物FeSO4Fe2(SO4)3KSCNK3Fe(SCN)6紅色除去：在蒸餾前，加入5FeSO4溶液EPOXIDESCCCCORCO3H中文

7、書：中文書：P458.28.2OHHOOOOOHOHOCCEpoxidesEpoxides-Reaction of Opening RingReaction of Opening Ring H2COCH2O CC 110。110。1.18D1.18D張力環(huán)能溶于水、乙醇、乙醚發(fā)生親核取代，重要有機(jī)合成中間體H2COCH2 NuHOCH2CH2NuH+ H2COCH2H2O/H+ROH/H+HXHCNBH3NH3RMgXLiAlH4HOCH2CH2OHROCH2CH2OHXCH2CH2OHHOCH2CH2CN(CH3CH2O)3BNH2CH2CH2OHRCH2CH2OHCH3CH2OHRMgX

8、+ CH2CH2ORCH2CH2OHCH3ONa +CH2CH2OCH3OCH2CH2OH1. Acid catalyst: 親核試劑進(jìn)攻取代較多的環(huán)氧烷碳原子(SN1) (1)CH3CHOCH2Nu(2)HCH3CHOCH2H+CH3CH HOCH2Nu2. Base catalyst：親核試劑進(jìn)攻取代較少的環(huán)氧烷碳原子(SN2)(1)CH3CHOCH2Nu(2)CH3CHOCH2Nu(1)位阻較大 CH3CHOCH2Nu（2）CH3CH NuCH2OHH2ONu:RO、PhO、RMgXCCOHHCH3CH3CH3ONa +?CH3OHUnsymmetrical EpoxideCCOHHCH

9、3CH3CH3ONa +CH3OHBasicLeast HinderedCCOHHCH3CH3CH3OH+H+CCOHHCH3CH3H+CCOHHCH3CH3HCCOHHHCH3CH3CCOHHHCH3OCH3CH3Most Substituted8.3 冠醚的絡(luò)合反應(yīng)和相轉(zhuǎn)移催化00.05腔體直徑腔體直徑12-C-415C518C621C7銨OOOOOO18-Crown-6Crown etherPhase-transfer agent冠醚與金屬離子所形成的絡(luò)合物可溶于低極性的有機(jī)溶劑，并且隨帶著負(fù)離子一起進(jìn)入有機(jī)溶劑中。 OOOOOOKMnO4溶于苯

10、中。紫色苯冠醚與金屬離子所形成的絡(luò)合物可溶于低極性的有機(jī)溶劑，并且隨帶著負(fù)離子一起進(jìn)入有機(jī)溶劑中。 OOOOOOKMnO4溶于苯中。紫色苯相轉(zhuǎn)移催化劑 能使互不相溶的兩相中的物質(zhì)發(fā)生反應(yīng)或加速反應(yīng)的催化劑。CH3KMnO4, Benzene二環(huán)己基18冠6COOH100% 界面 傳遞CN傳遞Cl水相有機(jī)相OOOOOOKOOOOOOKCN ClKCl KCN OOOOOOKCN RCl OOOOOOKClRCN RX + KCNPTCRCN + KX8.4 Preparation of ether(醚的制備醚的制備) 1.醇的分子間脫水簡單醚的制備 2.Willianmson合成法混合醚的制備2ROHH2SO4ROR + H2OHOCH2CH2CH2CH2OHH2SO4ORONa RORArONa ArOR+ RX不能用叔鹵代烷，以減少消除；芳基烷基醚的合成總是用酚鈉。 例1：合成CH3CH2OC(CH3)3解：(CH3)3CONa + CH3CH2Br C2H5OC(CH3)3不能用C2H5ONa和(CH3)3CBr,因為此時以消除反應(yīng)為主。CH3 CCH3 CH3BrC2H5ONaCH3 CCH3 CH2