难氧化2烷基苯工业来源课件

1、第五章 芳香烃 Aromatic compounds概述1.脂肪烃及芳香烃 Aliphatic and aromatic compounds芳香性 Aromaticity+Br2/CCl4+Br2/ FeBr3KMnO4Aromaticity 芳香性稳定的环，易取代，难加成，难氧化？2.烷基苯工业来源（ Industrial source of alkylbenzenes ）CoalPetroleum（见书第四节）Coal（no air)Coke(焦炭）Coal tar(煤焦油)+ Coal gasBenzene,toluene,xylenes,phenolcycloalkanesAromat

2、ic hydrocarbonCatalytic reforming催化重整馏分名称 沸点范围/ 主要成分 轻油 360 沥青、游离碳煤焦油的分馏产物3.分类 单环芳烃 多环芳烃 非苯芳烃 第一节 单环芳烃 苯及同系物（ benzene and homolog ）一.苯的结构 （structure of benzene）1.开库勒结构式（ Kekule structure）In 1825 M.FaradayIn 1834 E.MitscherlichIn 1865 August Kekule August KekuleI was sitting writing at my textbook,bu

3、t the work did not progress;my thoughts were elsewhere. I turned my chair to the fire,and dozed.Again the atoms were gamboling before my eyes.This time the smaller groups kept modestly in the beckground.My mental eye,rendered more acute by repeated visions of thiskind,could now distinguish larger st

4、ructures of manifold conformations;long rows,sometimes more closely fitted together;all twisting and turning in snake-like motion.But look!What was that?One of the snakes had seized hold of its own tail,and the form whirled mockingly before my eyes.As if by a flash of lightning I woke;I spent the re

5、st of the night working out the consequences of the hypothesis. Let us learn to dream,gentlemen,and then perhaps we shall learn the truth.August Kekule苯环结构的诞生是有机化学发展史上的一块里程碑Kekule formulaDewar formula 2.轨道理论Theory of orbitC SP2 （1） C sp2 hybridized （2） Particularly stable（3）电子离域 Electron Delocalizat

6、ionCH3CH3 Csp3-Csp3 154 pmCH2=CHCH3 Csp2-Csp3 150 pmCH2=CHCH=CH2 Csp2-Csp2 146 pmC6H6 Csp2-Csp2 139 pm3.分子轨道理论Theory of molecular orbit4.共振（ Resonance structure of benzene ）Resonance ContributorsLinus pauling电子离域与共振Electron Delocalization and Resonance 上述非经典结构式较好地表示了电子的离域，但是却无法告诉我们该结构中含有多少双键。因此化学家常用

7、共振结构（共振极限结构）来表示。p-electrons in conjugated dienes and benzene are delocalized定域电子：被限制在两个原子核区域内运动的电子离域电子：不局限于两个原子核区域内运动的电子这种电子的离域作用我们也称之为共轭作用How to drow resonance contributorsRules for Drawing Resonance ContributorsOnly electrons move. The nuclei of the atoms never moveThe only electrons that can move

8、 are electrons and nonbonding electronsThe total number of electrons in the molecule does not change, neither do the numbers of paired and unpaired electronsIn order to draw contributors, the electrons in one resonance contributor are moved to generate the next contributor.The electrons can be moved

9、 in one of the following ways（1） Move electrons toward a positive charge（2） Move electrons toward a bond（3） Move a nonbonding pair of electrons toward a bond（4） Move a single nonbonding electron toward a bond共振杂化体比它的任何一个共振式都要稳定共价键数目越多的共振式越稳定共振式中的电荷越分散就越稳定越稳定的共振式对共振杂化体的贡献越大1, 3-butadiene（5）相对稳定的共振式的数

10、目越多，共振杂化体越稳定（6）共振式越接近等价，共振杂化体越稳定二.命名 Nomenclature1. 简单 苯 （ benzene）Chlorobenzene NitrobenzeneSpecial namesToluene Aniline2. 相对复杂2-苯基戊烷2phenylpentane苯乙烯Styrenephenylethylene3.多取代基O-Dibromobenzene orthom-Dibromobenzene metap-Dibromobenzene para2-氯-3-硝基苯磺酸2-chloro-3-nitrobenzene-sulfonicacid优先次序：-COOH

11、， -SO3H ， -CN ， -CHO，C=O，-OH，-NH2，-R，- X ， NO2三、物理性质苯：无色透明,易燃液体。不溶于水。遇热、明火易燃烧、爆炸。能与氧化剂, 发生剧烈反应。蜡、树脂、油的溶剂; 合成化学制品和制药的中间体。汽油一种成份,含量2% 急性苯中毒：麻醉作用慢性中毒四、化学性质 （一）芳香亲电取代反应 （electrophilic aromatic substitution reactions）+Br2/ FeBr3Step 1:Step 2:：机理 Mechanism:Step 1:Reaction coordinate diagrams:1.卤代 Halogena

12、tionCatalyst:FeCl3, AlCl3, CuCl2, SbCl5BromobenzeneFeBr3 + Br2 FeBr4- + Br+diazepam2.硝化 NitrationNitrobenzene硝基苯 硝基苯; 密斑油; 苦杏仁油相对密度1.205。难溶于水硝基苯的主要毒作用3.磺化 Sulfonation reversible reaction苯磺酸 Benzenesulfonic acidsulfanilimideprontosil磺胺甲噁唑（sulfamethoxazole，sinomin，SMZ）又名新诺明噁唑 异噁唑4.傅-克烷基化反应 (Friedel-Cr

13、afts Alkylation )傅瑞尔克拉夫茨CFriedel 1832-1899J.A.Crafts 1839-1917 Note:催化剂 Catalyst:Lewis acids, AlCl3, FeCl3, ZnCl2, SnCl4, BF3 重排Rearrangement may occur in alkylation1010多元取代物 polysubstitutionLimitationAromatic rings containingthegroup do not undergo F-C Alkylation polyhalogenated alkanes？alcohol,alkene5.傅-克酰基化反应 (Friedel-Crafts Acyla