大学有机化学第1章绪论.ppt

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1、2023/11/12,有机化学,2023/11/12,Contact,学院楼517室、521室、219室5681086(office 219)5688069-8219(office 219)5688069-8517(lab 517)5688069-8521(lab 521)E-mail:,2023/11/12,有机化学参考书,1.有机化学 汪小兰 高等教育出版社2.有机化学例题与习题 王长风 曹玉蓉高等教育出版社 3.Organic Chemistry T.W.Graham Solomons&Craig B.Fryhle John Wiley&Sons,Inc.,2023/11/12,4.有机

2、化学学习指导及考研试题精解 修订版 姜文凤 陈洪博 大连理工大学出版社5.有机化学 倪沛州主编（药学专业）6.基础有机化学 上下册 邢其毅 徐瑞秋 周政 费伟伟 高等教育出版社 第二版 7.基础有机化学 习题解答与解题示例 邢其毅 徐瑞秋 费伟伟 北京大学出版社8.有机化学习题解 张宝申 庞美丽 南开大学出 版社,2023/11/12,9.有机化学习题精解 樊杰 葛树丰 周晴中 田桂玲 李翠娟 北京大学出版社 10.有机化学 G.Patrick 科学出版社（精要速览系列 英文版 影印本）11.有机化学学习指导及考研试题精解 修订版 姜文凤 陈洪博 大连理工大学出版社 12.有机化学习题精解（全

3、美精典学习指导系列）（美）H.迈斯利克 科学出版社,2023/11/12,关于考试、考勤、作业及成绩,1.闭卷考试；2.考勤，请假以每大节的第2小节上课之前的假条为准;3.作业分2部分，在相应章节结束后1周内提交；4.成绩由期末成绩、平时成绩构成。,2023/11/12,The Age of Organic Chemistry,95%of all known compounds composed of carbon Organic Chemistry crucial to our way of life:clothing,materials(polymers),petroleum,medici

4、ne,OUR BODIES 50%of chemists in Organic Chemistry,2023/11/12,第1章 绪论,本章重点：有机化合物的命名、路易斯结构式、化学键、分子间力对有机化合物物理性质的影响，杂化轨道 Organic chemistry is the chemistry of the compounds of carbon.The compounds of carbon are central to life on this planet.Carbon compounds include DNAs,the giant helical molecules that

5、contain all of our genetic information.They include the proteins that catalyze all of the reactions in our body and that constitute the essential compounds of our blood,muscle,and skin.Together with oxygen from the air we breathe,carbon compounds furnish the energy that sustains life.,2023/11/12,One

6、 theory of the origin of life on earth starts with the proposal that early in Earths history most of its carbon atoms were present in the form of the gas methane,CH4.This simple organic compound is assumed to have been a main constituent of Earths primordial(原始的)atmosphere,together with carbon dioxi

7、de,water,ammonia,and hydrogen.Experiments have shown that when electric discharges(like lightning)and other forms of highly energetic radiations pass through this kind of atmosphere,these simple compounds become fragmented into highly reactive pieces.,2023/11/12,These pieces then combine to form mor

8、e complex compounds called amino acids,formaldehyde,hydrogen cyanide,purines(嘌呤),and pyrimidines(嘧啶).It is thought that these,and other compounds formed in the primordial atmosphere,were carried by rain into the sea until the sea became a vast storehouse containing all of the compounds necessary for

9、 the emergence of life.,2023/11/12,Amino acids can react with each other to become proteins.Molecules of formaldehyde can react with each other to produce sugars,and some of the sugars,together with inorganic phosphates,may have reacted with purines and pyrimidines to become simple molecules of RNAs

10、 and DNAs.Molecules of RNA,because they can carry genetic information and some can catalyze reactions,could have been instrumental in the emergence of the first self-replicating systems.From these first systems,in a manner far from understood,through the long process of natural selection may have co

11、me all of the living thing on Earth today.,2023/11/12,Not only are we composed largely of organic compounds,not only are we derived from and nourished by them,we also live in a time when the central role of organic chemistry in medicine,bioengineering,nanotechnology,and other disciplines is more app

12、arent than ever.The clothing we wear,whether a natural substance such as wool or cotton or a synthetic such as nylon or polyester,is made of carbon compounds.Many of the materials that go into the houses that shelter us are organic.The gasoline that propels our automobiles,the rubber of their tires,

13、and the plastic of their interiors are all organic.Most of the medicines that help us cure diseases and relieve suffering are organic.,2023/11/12,Organic chemicals are also factors in some of our most serious problems.Many of the organic chemicals introduced into the environment in years have had co

14、nsequences far beyond those originally intended.In a number of these situations,however,methods that are more environment-friendly are being developed.,2023/11/12,For example,natural insect attractants called pheromones(信息素)are now used to lure insects into traps,instead of wide-spread pesticide app

15、lication.International negotiations to replace with less reactive compounds organic refrigerants and aerosol propellants that destroy Earths ozone layer hold promise for a worldwide rescue of our outer atmosphere.Cars with more efficient combustion engines use less gasoline and help reduce the massi

16、ve amount of automobile pollutants that foul the air and contribute to the greenhouse effect.,2023/11/12,Inasmuch as this is an age where many disciplines are linked by organic chemistry,it is also an age where our working philosophy is reduce,reuse,and recycle.Organic compounds play a big part in t

17、his effort.Plastics that were once bottles for soft drinks and milk are recycled into fabric and carpet.Paper recycling allows harvesting of fewer trees for pulp.Engine oils,paints,and solvents are collected by environmental agencies and recycled.Chemistry laboratories conduct experiments on smaller

18、 and smaller scales,thereby using less material and generating less waste.,2023/11/12,Recognizing and encouraging these efforts,the U.S.Environmental Protection Agency honors the most effective innovators with Presidential Green Chemistry Awards.On all fronts,chemists are developing environment-frie

19、ndly procedures for the worlds benefit.Clearly,organic chemistry is associated with nearly every aspect of our existence.We would be wise to understand it as best we can.,2023/11/12,地球上的生命所含有的20种氨基酸为手性分子且为左旋异构体，而一般认为氨基酸等对生命十分重要的物质在生命出现以前已经存在，从理论上讲，合成氨基酸时，形成的应是左旋和右旋的外消旋异构体，因此有人提出可能是宇宙高能电磁辐射使得左旋氨基酸比右旋

20、氨基酸多，正是由于左旋氨基酸较多，才可能带来地球上生命的进化。,2023/11/12,一、有机化学的发展The development of organic chemistryas a science,Modern organic chemistry is the chemistry of carbon compounds.(Kekul published in 1861)人类使用有机物和应用有机反应的历史可能有数千年。人类最早应用的有机反应有可能追溯到火的发现。古埃及人用靛青和茜素(indigo and alizarin)染布；腓尼基人著名的“蓝紫”(“royal purple”)也是一种有

21、机物，由软体动物(mollusks)获得。葡萄发酵制造乙醇和酸葡萄酒的酸味在圣经中都有描述，证明在此之前人类对此已有了解。,2023/11/12,然而，作为一门科学，有机化学只有不到200年的历史。在1780s科学家开始将有机物和无机物进行区分。将有机物定义为可从有生命力的有机体/生命体获得的化合物。将无机物定义为可从无生命力来源获得的化合物。此时盛行“生命力论（vitalism）”，认为有机物的合成需要“生命力(vital force)”；化学家也认为有机合成只能在活的有机体内发生，不可能在化学实验室内的烧瓶中进行。,2023/11/12,Between 1828 and 1850 a nu

22、mber of compounds that were clearly“organic”were synthesized from sources that were clearly“inorganic”.1828:Friedrich Whler found that the organic compound urea(a constituent of urine)could be made by evaporating an aqueous solution containing the inorganic compound ammonium cyanate:,2023/11/12,在186

23、2年Friedrich Whler又合成出乙炔：自Whler合成以后，“生命力论”逐渐在科学领域消失，但“生命力论”的出现使得自1850年以来有机化学作为一门科学的繁荣成为可能。一种理论或思想的提出，难免有其片面性，对旧有思想的扬弃可能带来更加进步的思想。,2023/11/12,虽然生命力论已经过时，但“有机(organic)”一词有时仍被用来表示“来源于有机体(coming from living organisms)”，如有机维生素(organic vitamins)、有机肥料(organic fertilizers)等。经常用到的“有机食品”意指未经合成肥料和农药获得的食品；“有机维生素

24、”被特指从天然产物分离获得而非由化学家合成的维生素。有许多问题不容忽视，比如食品的农药残留问题，而“有机农业”可能更加环保，天然维生素可能含有合成维生素没有的有益物质，但就纯粹的物质而言，无法证明天然维生素C比合成维生素C更有益于健康，因为二者在各个方面都是一致的。在现代化学中，对来源于生物体化合物的研究称为天然产物化学(natural products chemistry).,2023/11/12,Empirical and molecular formulas,In the 18th and 19th centuries extremely important advances were

25、made in the development of qualitative and quantitative methods for analyzing organic compounds.1784:Antoine Lavoisier first showed that organic compounds were composed primarily of C,H and O.1811-1831:Justus Liebig,J.J.Berzelius and J.B.A.Dumas developed quantitative methods for determining the com

26、position of organic compounds.,2023/11/12,1860:Stanislao Cannizzaro showed that the earlier hypothesis of Amedeo Avogadro(1811)could be used to distinguish between empirical and molecular formulas.As a result,many molecules that had appeared earlier to have the same formula were seen to be composed

27、of different numbers of atoms.For example,ethene,cyclopentane,and cyclohexane all have the same empirical formula:CH2.However,they have molecular formula:C2H4,C5H10,and C6H12,respectively.,2023/11/12,在1858年和1861年之间，August Kekul,Archibald Scott Couper和Alexander M.Butlerov各自独立提出化学中最基本的原理之一：结构原理。核心内容有2

28、点：1、有机化合物中的原子能形成一定数目的键，这一能力称为原子价（valence）。如碳为4价，即C能形成4个键，类似地，O为2价、氢和一般情况下的卤素为1价。,2023/11/12,2、1个C原子可用其1个或更多原子价与另外的C原子形成化学键。比如可形成单键、双键和三键。,2023/11/12,上述结构原理可以很好地释疑关于异构体的问题。所谓异构体（或组成异构体,constitutional isomers）是指具有相同分子式的不同化合物。用结构式能够更加明确地将化合物分子中原子之间的连接表示出来。,2023/11/12,在1874年，J.H.vant Hoff 和J.A.Le Bel各自独

29、立将2维结构式发展到3维结构式，即立体结构式。1916年G.N.Lewis和W.Kssel提出化学键可分为离子键和共价键2大类，并服从8电子规则(octet rule)。原子吸引电子的能力可用电负性(electronegativity)来表示。,2023/11/12,Electronegativities of some of the elements,2023/11/12,原子得或失电子形成带电荷的粒子-离子。所谓离子键即相反电荷离子之间的一种吸引力。如LiF。由于离子之间很强的静电力，离子性物质（经常称为盐）一般都是高熔点的固体，熔点经常高于1000C。在极性溶剂如水中，离子能够溶解，所成

30、溶液具有导电性。,2023/11/12,具有相同或相近电负性的原子之间难以实现电子的完全转移，原子之间通过共享电子获得惰性气体结构，原子间所形成的键-共价键，原子间通过共价键形成的产物即分子。分子结构式可用价层电子点来表示，其中共价键还可用横线表示，所形成的结构式称为Lewis结构式。如,2023/11/12,8电子规则只适于第2周期元素，即使第2周期元素也有例外，如Be,B的化合物（BF3的B原子周围只有6个电子）；对于第3周期及其后的元素，由于原子的d轨道也可用于成键，在价电子层容许8个以上的电子，因此能形成4个以上的共价键，如PCl5，SF6。,2023/11/12,Lewis结构式是人

31、为将价电子进行分布，因此对于很多分子和离子可能写出多个等效Lewis结构式。如碳酸根离子,X线研究表明C-O键长相等且比C-O单键短。可用共振理论(resonance theory)解释。,2023/11/12,共振理论具有以下6特点：1、共振结构只存在于纸上；2、在写共振结构时只允许移动电子；3、所有共振结构必须是正确的Lewis结构式；4、分子的实际能量要比可能的共振结构式能量低-共振稳定化；5、等效的共振式对杂化具有相同的贡献，这样的体系具有更大的共振稳定化，如烯丙基正离子、苯等；6、某一结构越稳定，对杂化贡献越大,这对设计化学反应和研究有机反应机理都十分重要。,2023/11/12,a

32、.结构具有越多的共价键越稳定；如1，3-丁二烯b.所有原子的价电子层全满特别稳定，对杂化贡献大；如甲氧亚甲碳正离子 不如相应的氧鎓离子稳定c.电荷分离会降低稳定性。如氯乙烯要比具有氯正离子和碳负离子的结构稳定d.负电荷在高电负性原子要比负电荷在低电负性或非电负性原子上时稳定。,2023/11/12,1926年Erwin Schrdinger,Werner Heisenberg和Paul Dirac几乎同时提出波理论和量子理论，奠定了现代化学发展的基础。几个月之后，Max Born对波函数的平方（2）给出物理意义的解释，认为2是在指定领域发现电子的几率大小。在3维空间对2画图，就得到为大家熟知的

33、s,p,d原子轨道。所谓原子轨道是指在空间中发现一个电子的几率较大的区域，几率一般取值90-95%。原子轨道的杂化形成分子轨道。(第18章自学),2023/11/12,二、有机化合物的命名,有机化合物的组成、结构决定了有机物的物理和化学性能。有机化合物多数带有不同的反应性基团-官能团，按照官能团可将有机物分为烷烃、烯烃、炔烃、卤代烃、醇、醚、醛、酮、酸、酯等类型。对有机化合物进行合理的表述，主要包括结构式和文字叙述即命名2种方式。有机化合物的结构式主要有球-棒模型(ball-and-stick model)、点式结构(dot structure)、短线结构式(dash formula)、紧密型

34、结构式(condensed formula)和键线结构式(bond-line formula)五种。,2023/11/12,前2种表达方式球-棒模型和点式结构（需画出所有价电子）由于书写繁琐而不常用,2023/11/12,短线结构式、紧密型结构式和键线结构式较为常用。,2023/11/12,在书写结构式时，孤对电子也常常被忽略不写，但在表示有机化学反应特别是反应机理时，将孤对电子表示出来会更有帮助。在不引起疑义的前提下，可用下标来表示相同结构单元的数目。如2-甲基丁烷（异戊烷）可表示为(CH3)2CHCH2CH3、正庚烷可表示为CH3(CH2)5CH3.,2023/11/12,对有机化合物进行

35、规范的文字表述十分重要，虽然有一些俗名还被使用，但广泛使用的是根据IUPAC(the International Union of Pure and Applied Chemistry)所提出的命名方法对化合物命名。,2023/11/12,直链烷烃和烃基的命名,2023/11/12,Other unbranched alkanes,2023/11/12,2023/11/12,2023/11/12,2023/11/12,2023/11/12,Nomenclature of branched-chain alkanes,1.Locate the longest continuous chain o

36、f carbon atoms;this chain determines the parent name for the alkane.,2023/11/12,2.Numbering the longest chain beginning with the end of the chain nearer the substituent.,2023/11/12,3.Use the numbers obtained by application of rule 2 to designate the location of the substituent group.,2023/11/12,4.Wh

37、en two or more substituents are present,give each substituent a number corresponding to its location on the longest chain.,2023/11/12,5.When two substituents are present on the same carbon atom,use that number twice.,2023/11/12,6.When two or more substituents are identical,indicate this by the use o

38、f prefixes di-,tri-,tetra-,and so on.,2023/11/12,7.When two chains of equal length compete for selection as parent chain,choose the chain with the greater number of substituents:,2023/11/12,8.When branching first occurs at an equal distance from either end of the longest chain,choose the name that g

39、ives the lower number at the first point of difference:,2023/11/12,比较下述烷烃的命名,2023/11/12,Nomenclature of branched alkyl groups,Systematic nomenclature of alkyl groups is similar to that for branched-chain alkanes,with the provision that numbering always begins at the point where group is attached to

40、the main chain.,2023/11/12,2023/11/12,Nomenclature of alkyl halides,Alkanes bearing halogen substituents are named in the IUPAC substitutive system as haloalkanes.When the parent chain has both a halo and an alkyl substituent attached to it,number the chain from the end nearer the first substituent,

41、regardless of whether it is halo or alkyl.If two substituents are of equal distance from the end of the chain,then number the chain from the end nearer the substituent that has alphabetical precedence:,2023/11/12,2023/11/12,Common names for many simple haloalkanes are still widely used,however.In th

42、is common nomenclature system,called functional class nomenclature,haloalkanes are named as alkyl halide.(The following names are also accepted by the IUPAC.),2023/11/12,Nomenclature of alcohols,In what is called IUPAC substitutive nomenclature,a name may have as many as four features:locants,prefix

43、es,parent compound,and suffixes.Consider the following compound as an illustration without,for the moment,being concerned as to how the name arises:,2023/11/12,The locant 4-tells that the substituent methyl group,named as prefix,is attached to the parent compound at C4.The parent compound contains s

44、ix carbon atoms and no multiple bonds,hence the parent name hexane,and it is an alcohol;therefore it has the suffix ol.The locant 1-tells the C1 bears the hydroxyl group.In general,numbering of the chain always begins at the end nearer the group named as a suffix.,2023/11/12,The locant for the suffi

45、x(whether it is for an alcohol or another functional group)may be placed before the parent name,as in the above example or,according to a 1993 IUPAC revision of the rules,immediately before the suffix.Both methods are IUPAC approved.Therefore,the above compound could also be named 4-methylhexan-1-ol

46、.,2023/11/12,The following procedures should be followed in giving alcohol IUPAC substitutive names:1.Select the longest continuous carbon chain to which the hydroxyl is directly attached.Changed the name of the alkane corresponding to this chain by dropping the final e and adding the suffix ol.2.Nu

47、mber the longest continuous carbon chain so as to give the carbon atom bearing the hydroxyl group the lower number.Indicate the position of the hydroxyl group by using this number as a locant;indicate the positions of other substituents(as prefixes)by using the numbers correspoding to their position

48、s along the carbon chain as locants.,2023/11/12,The following examples show how these rules are applied:,2023/11/12,Simple alcohols are often called by common functional class names that are also approved by the IUPAC.In addition to methyl alcohol,ethyl alcohol,and propyl alcohol,there are several o

49、thers,including the following:,2023/11/12,Alcohols containing two hydroxyl groups are commonly called glycols.In the IUPAC substitutive system they are named as diols:,2023/11/12,Nomenclature of monocyclic compounds,Cycloalkanes with only one ring are named by attaching the prefix cyclo-to the names

50、 of the alkanes possessing the same number of carbon atoms.For example,2023/11/12,Naming substituted cycloalkanes is straightforward:we naming them as alkylcycloalkanes,halocycloalkanes,alkylcycloalkanols,and so on.If only one substituent is present,it is not necessary to designate its position.When