第第第 第第第 洛洛洛洛洛洛洛洛洛洛洛洛洛洛
Dec 31, 2015
第三章 单烯烃
洛阳师院化学系有机化学教研室
官能团: ,通式:官能团: ,通式: CCnnHH2n2n..
第一节 烯烃的结构第一节 烯烃的结构
乙烯的键参数乙烯的键参数
C C
CH
HC
H
H
0.108nm
0.133nm
121.7
117
C=C 键能610kJ/mol
C a r b o n s p 2 ( t r i g o n a l , 3 + 1 b o n d s )
sp 2sp 2sp 2
2p z2p y2p x
2s
2p z
hybridised C atom in C 2 X 4 isolated C atom
120
ppsp 2 sp 2
sp 2sp 2C C
Planar
154pm134pm
-Bonding(Bonding molecular orbital)
烯烃的反应C C
C
H ¼Ó³É¡¢ Ñõ»¯¡¢ »¹ Ô ¡¢ ¾ÛºÏ
HÉϵķ´ Ó¦£¨ Ñõ»¯¡¢ ±́ú £©
乙烯分子的形成乙烯模型
第二节 烯烃的同分异构和命名第二节 烯烃的同分异构和命名 一、烯烃的同分异构一、烯烃的同分异构
烯烃的异构包括碳干异构、位置异构烯烃的异构包括碳干异构、位置异构、顺反异构。、顺反异构。
例:丁烯有例:丁烯有 55 种同分异构体:种同分异构体:
CH3CH2 CH CHCH3 CH CH2 CH3 CH3C CH2CH3(1) 1-¶¡ Ï© £¨ 2£©2-¶¡ Ï©
£¨ 3£©Ò춡 ϩλ ÖÃÒì¹¹ ̼¸ÉÒì¹¹
λ ÖÃÒì¹¹
C CH3C
H
CH3
HC C
H3C
H
H
CH3(4) ˳ -2-¶¡ Ï© £¨ 5£©·´ -2-¶¡ Ï©
˳·´ Òì¹¹
顺( cis):两个双键上的氢原子处于双键的同一侧;反( trans):~~~处于异侧。C C
a c
dba b, c dʱ́ æÔÚ
˳·´ Òì¹¹ Ìå
二、烯烃的命名二、烯烃的命名1. 1. 选择含双键最长的碳链作为主链(母体选择含双键最长的碳链作为主链(母体),根据主链碳原子数命名为某烯。),根据主链碳原子数命名为某烯。
2. 2. 从靠近双键最近的一端开始编号。从靠近双键最近的一端开始编号。3. 3. 命名时双键的位次必须表明,以双键碳命名时双键的位次必须表明,以双键碳原子中编号小的表示。 原子中编号小的表示。
5,5- 二甲基 -1- 己烯
CH2 CH2 CH3 CH CH2
CH3 CH2 CH CH2 CH3 CH CH CH3
Ethene Propene
1-Butene 2-Butene
“Ethylene” “Propylene”
C CH CH3
CH3
CH3
2-Methyl-2-butene
CH3 CH CH2 CH2 CH CH CH3
CH3
6-Methyl-2-heptene
CH3 CH CH2 CH2 CH CH CH3
CH3
6-Methyl-2-heptene
烯基烯基 Ethyl CHEthyl CH22=CH- Vinyl=CH- Vinyl
1-Propenyl1-Propenyl
2-Butenyl2-Butenyl
2-Pentenyl2-PentenylIsopropenyl(for 1-methylvinyl)
Allyl
E-Z Nomenclature
C C
* *C C
*
*(Z) (E)
E-Z Nomenclature Rules
SEQUENCE RULE 1: If the four atoms directly attached to the double bond are all different, priority depends on atomic number, with the atom of higher atomic number receiving the higher priority.
COROLLARY: If two atoms are isotopes of the same element, the heavier isotope receives the higher priority.
E-Z Nomenclature Rules
SEQUENCE RULE 2: If the relative priority of two groups cannot be decided by Rule 1, it shall be determined by a similar comparison of the next atoms in the groups (and so on, if necessary), working outward in ranks from the double bond.
E-Z Nomenclature Rules
To complete the IUPAC name of a particular isomer, enclose the (E) or (Z) symbol in parentheses and place it at the front of the entire name of the compound. Separate the (E) or (Z) symbol from the rest of the name with a hyphen.
Examples
C CH3C
H
CH3
CH2CH3
CH3(C)CH3>H
C2H5(µÚ¶þÔ ×Ó£º C,H,H)
CH3(µÚ¶þÔ ×Ó£º H,H,H)C2H5>CH3
(E)-3-¼×»ù-2-Îì Ï©
Question: (CH3)3C- 与
-CH2Cl 哪个为优先基团?
C C
CH3
H
CH2
CH2
CH2CH3
CH2CHCH2
CH3
CH3
trans-6-Methyl-3-propyl-2-octene(Don’t worry about “trans” until Chapter 4)
IntentionIntention
1. Z、 E 和顺( Cis)、反( Trans )并不总是一一对应的。
第三节 烯烃的化学性质第三节 烯烃的化学性质
典型反应:加成反应--在反应中, 典型反应:加成反应--在反应中, 键断开,两个不饱和原子和其它原子或键断开,两个不饱和原子和其它原子或原子团结合,形成两个原子团结合,形成两个键,这种反应键,这种反应称为加成反应。称为加成反应。
Addition Reactions
+C C X Y C C
X Y
一、催化氢化一、催化氢化RCH CH2 + H2 RCH2CH3 + Ç⻯ÈÈ´ß »¯¼Á
催化剂催化剂异相催化剂:铂黑、钯粉、异相催化剂:铂黑、钯粉、 RaneyRaney Ni; Ni;
FeFe 、、 CrCr 、、 Cu.Cu. 均相催化剂:主要为过渡金均相催化剂:主要为过渡金
属配合物属配合物´ß »¯Ç⻯»úÖÆ£º
H2 H HC C
H H
HHH H C C
H H
HH H-CH2CH2-H
乙烯加氢
Hydrogenation of Alkenes
+ H2
Pt, Pd,
or NiR CH CH R R CH CH R
H H
syn-addition
(stereospecific)
Also PtO2 -- sometimes Ru, Rh, or Re
HYDROGEN ADSORBS ON THE HYDROGEN ADSORBS ON THE SURFACE OF THE CATALYSTSURFACE OF THE CATALYST
n H2 + Pt Pt(H )2n
H H H.Hydrogen Adsorbed onCatalyst Surface
. .finely-dividedparticlesdispersed insolution
Pt Pt PtPt Pt
.H
.H
Pt
.H
Pt Pt Pt Pt Pt
.
.H.
H
.H
.H .
H.H.
H
H H
CATALYST
MECHANISM OF HYDROGENATIONMECHANISM OF HYDROGENATION
.H.
H
.H
.H .
H.H.
H.H
.H
HYDROGENADSORBS
MECHANISM OF HYDROGENATIONMECHANISM OF HYDROGENATION
.H.
H
.H
.H .
H.H.
H
.H
RR
R R
. ..H
ALKENEAPPROACHES
MECHANISM OF HYDROGENATIONMECHANISM OF HYDROGENATION
.H.
H
.H
.H .
H.H.
H
.H
.H
RR
R R
. .
ALKENE PICKS UPTWO HYDROGENS
MECHANISM OF HYDROGENATIONMECHANISM OF HYDROGENATION
.H.
H
.H
.H .
H.H.
H
RRR R
. .H
..H
ALKANE ISFORMED
MECHANISM OF HYDROGENATIONMECHANISM OF HYDROGENATION
氢化热:氢化热: 11molmol 不饱和化合物氢化不饱和化合物氢化时放出的热量。时放出的热量。
氢化热的大小反应烯烃的相对稳定性。氢化热的大小反应烯烃的相对稳定性。
双键碳原子上的烷基越多,烯烃越稳定。双键碳原子上的烷基越多,烯烃越稳定。
RR22C=CRC=CR22>R>R22C=CHR>RCH=CHR>C=CHR>RCH=CHR>
RCH=CHRCH=CH22>CH>CH22=CH=CH22..
2-2- 甲基丙烯甲基丙烯 >> 反反 -2--2- 丁烯丁烯 >> 顺顺 -2--2- 丁烯丁烯 >1->1- 丁烯丁烯。。
Alkene StabilityAlkene Stability
C C C CCH3
H
H3C H
CH3
H
CH3
H
acid
catalyst
76% 24%
Steric Strain
二、亲电加成二、亲电加成Electrophilic Addition to a Double Bond
+CH2 CH2 X Y X CH2 CH2 Y
亲电试剂( E +):凡缺电子物种,如正离子等。
A d d i t i o n
R e d u c t i o n i n b o n d o r d e r a n d c h a n g e i n h y b r i d i s a t i o n
f r o m s p 2 t o s p 3 .
C CX Y
C
X
C
Y
sp 2sp 3 sp 2
sp 3
1. 与酸的加成强酸如硫酸、氢卤酸可以直接作用;弱有机酸(如乙酸)、醇、水等要在强酸催化下进行。
1 )与卤化氢加成
( Addition of Hydrogen Halides) +CH CHR R H X R CH CH R
H X
卤化氢对烯烃加成的活性卤化氢对烯烃加成的活性次序:次序: HI>HBr>HClHI>HBr>HCl
Markovnikov Addition to an Alkene
+ +
majorproduct
minorproduct
CH3 CH CH2 H
Br
CH3 CH CH2 H Br CH3 CH CH2 Br
H
Markovnikov Addition to an Alkene
+ +
major product minor productX = Cl, Br, I
C CH2
CH3
CH3
H X CH3 C CH2
CH3
X
H CH3 C CH2
CH3
H
X
Markovnikov Rule
In the ionic addition of an acid to the carbon-carbon double bond of an alkene, the hydrogen of the acid attaches itself to the carbon atom which already holds the greater number of hydrogens.“Them that has, gets!”“The richer get richer!”
(V. W. Markovnikov -- 1838 - 1904)
CCH3
CH3
CH2 CCH3
CH3
CH3
Cl
+ CHCH3 CH2
Cl
CH3HCl
major minor
REGIOSELECTIVEREGIOSELECTIVE REACTIONREACTION
one of the possible products is formedin larger amounts than the other one
Compare REGIOSPECIFICREGIOSPECIFIConly one of the possible products isformed (100%).
区位选择性反应
MARKOVNIKOV RULEMARKOVNIKOV RULE
CH2
+ HCl
CH3
Cl
When adding HX to a double bond theWhen adding HX to a double bond thehydrogen of HX goes to the carbonhydrogen of HX goes to the carbonwhich already has the most hydrogenswhich already has the most hydrogens
..... conversely, the anion X adds to the mosthighly substituted carbon ( the carbon withmost alkyl groups attached).
KARASCH 效应(过氧化物效应在过氧化物存在下,氢溴酸与
不对称烯烃加成时,反应取向是 Anti-Markovnikov rule.CH3CH CH2 + HBr CH3CH2CH2Br
¹ý Ñõ»¯Îï
Reading Assignment:
本章第七节
22 )与硫酸加成)与硫酸加成H2C CH2 + H2SO4 CH3CH2OSO2OH
0-15C
ÁòËáÇâÒÒõ¥98£¥H2SO4CH2 CH2 H2O
90CCH3CH2OH
与不对称烯烃加成同样遵循 Markovnikov rule.
用上法制备醇叫间接水合,设备腐蚀严重。
Addition of Sulfuric Acid to an Alkene
+ H2SO4(cold, concentrated)
an alkyl hydrogen sulfate
CH CH2R R CH CH2 H
O
S
OH
OO
Addition of Water to an Alkene
+ H2OH2SO4
an alcohol
R CH CH2 R CH CH2 H
OH
直接水合:直接水合:CH3CH CH2 CH3CHCH3
OH
H2O/H3PO4»ò¹è ÔåÍÁ
300C,7MPa
2. 与卤素加成C C + X2 C C
X X Br/CCl4 溶液用来检验烯烃
卤素对烯烃加成的活性次序:F2>Cl2>Br
2>I2( 不反应)
ICl 、 IBr次卤酸( X2+H2O)与不对称烯烃加成的主要产物为何?
Halohydrin Formation
Br2
H2OR CH CH R R CH CH R
OH Br
a bromohydrinHOBr
卤代醇的形成
3. 3. 与乙硼烷加成与乙硼烷加成(( 硼氢化反应:由硼氢化反应:由 BB-- HH 键对烯烃双键对烯烃双键进行的加成反应)由键进行的加成反应)由 CC. . HH. . BBrownrown建立建立
C C + B2H6 C CH BH2
2BH3 B2H6
乙基硼 二乙基硼
三乙基硼
CH3CH CH2 CH3CH2CH2BH2B2H6 2B2H6
(CH3CH2CH2)3B
绝大多数烯烃与二硼烷的加成产物是三烷基硼,少数立体障碍大的烯烃则停留在一烷基硼或二烷基硼阶段。
Sia2BHSia2BH,, thBH2(HBH2thBH2(HBH2)) , 9-, 9-BBNBBN
(CH3)2C CHCH3B2H6
THF[(CH3)2CHCH ]
CH3
2BH
二(1,2-二甲基丙基)硼烷DIsiamylborane(Sia2BH)
(CH3)2C C(CH3)2 B2H6
THF(CH3)2CHC
CH3
BH2
CH3
1,1,2-三甲基丙基硼烷thexylborane(thBH2,or HBH2)
B2H6
THF
BH
9-硼二环[3.3.1]壬烷9-borabicyclo[3.3.1]nonane(9-BBN)
特点:特点:
特点: 1. 氢加到含氢较少的双键碳原子上; 2. 顺式加成,选择性好; 3. 产率高;4. 反应条件温和。
合成应用:合成应用:
C C + B2H6
硼氢化C CH
3B
氧化C C OH
硼氢化-氧化反应:
例例 11
CH3
OHH
CH3
OH
H
解:
CH3
OHH2SO4
CH3
B2H6
H
CH3
BH2
H
顺式加成H2O2, OH- H
CH3
OH
H
用用 KMnOKMnO44 溶液来溶液来鉴定不饱和烃。鉴定不饱和烃。
三、氧化反应三、氧化反应 1. 1. 用用 KMnOKMnO44或或 OsOOsO4 4 ((四氧化锇)氧四氧化锇)氧
化化3RCH CH2 + 2KMnO4 + 4H2O 3RCH
OH
CH2 +
OH2MnO2 + 2KOH
¼îÐÔ»ò
ÖÐÐÔ½éÖÊ
顺 -1, 2-二醇
由于二元醇的进一步氧化,反应条件不易控制,收率低。如用四氧化锇代替高锰酸钾,则收率大大提高,但毒性大。
在酸性介质中,氧化更易进行,且发生双键断裂。
CH2= CO2 , RCH= RCOOH
RR'C= RR'C=O
2. 2. 臭氧化臭氧化
另外,有 H2O2 产生,能使醛进一步氧化成羧酸。
H2O
还原水解可以避免产物的进一步氧化还原水解可以避免产物的进一步氧化
有种常用的还原剂:有种常用的还原剂:
11)) Zn/HZn/H22OO
22)) HH22,Pd,Pd
臭氧化还原水解产物:臭氧化还原水解产物:CH2= CH2O , RCH= RCHO
RR'C= RR'C=O
推测烯烃的结构
A L K E N E O X I D A T I O N - O Z O N O L Y S I S
NO OVEROXIDATION
(ii) Zn, H 2 O
(i) O 3C C C O O C
O v e r a l l u s e f u l d i a g n o s t i c t o o l f o r t h e
d e t e r m i n a t i o n o f d o u b l e b o n d p l a c e m e n t .
V e r y u s e f u l s y n t h e t i c r e a c t i o n f o r t h e c r e a t i o n
o f c a r b o n y l c o m p o u n d s w i t h a b s o l u t e
c o n t r o l o v e r o v e r t h e p l a c e m e n t o f t h e c a r b o n y l .
33 .催化氧化.催化氧化
CH2 CH2 + O2 O
CH2H2CAg200-300 C
Organic Reaction
R
O
四、聚合反应四、聚合反应
聚合反应:由单体分子相互作用生成聚合反应:由单体分子相互作用生成高分子化合物的反应叫聚合反应。高分子化合物的反应叫聚合反应。
nH2C=CH2 TiCl4£ Al(C2H5)3
0.1£ 1MPa60£ 75 CÒÒÏ©£¨ µ¥Ìå £© ¾ÛÒÒÏ©£¨ ¸ß ·Ö×Ó£©
CH2 CH2( )n
Polymerization of Propene1)
+ H2SO4 + HSO4
_
+CH3 CH CH2 CH3 CH CH2 H
+CH3 CH CH3
2)+
slow
+CH3 CH CH2 CH3 CH CH2 CH CH3
CH3
3)
+CH3 CH CH2 CH CH3
CH3
+ HSO4
_CH3 CH CH CH CH3
CH3
+ H SO2 OH
五、五、-- H H 上的反应上的反应
1. 1. 卤代卤代CH3CH CH2 + Cl2 ClCH2CH CH2
300 C
CH3CH CH2 + Br2 BrCH2CH CH2500 C
C C C C X
¹ÙÄÜÍÅ
H
-- HH 卤代历程卤代历程 (( 自由基取自由基取代代 ))
2. 氧化
CH3CH CH2 + NH3 + O2 CH2
´ß »¯¼Á CHCN + H2O
丙烯腈
第五节 烯烃的制备第五节 烯烃的制备一、消除反应一、消除反应
1. 1. 一卤代烃脱一卤代烃脱 HXHX
2. 2. 邻二卤代烃脱邻二卤代烃脱 XX22
3. 3. 醇脱醇脱 HH22OO
C C
H X
C C + HX
- 消除
C C
XX C C + ZnX2
Saytzeff RuleSaytzeff RuleCH3CH2CH(OH)CH3 CH3CH CHCH3 + CH3CH2CH CH2
81% 19%
H2SO4
¼ÓÈÈ
二、炔烃的还原
CH3CHCHCH2CH CHCH3OHH3C
CH2CH(CH3)CH CHCH CHCH3Al2O3
共轭烯烃
溴鎓离子反式加
成
第六节 烯烃的亲电加成反应历程第六节 烯烃的亲电加成反应历程1.1. 烯烃与溴加成烯烃与溴加成
+ Br Br- C
CBr + Br-
C
CBrBr- +
C
C BrBr
C
C
在极性分子诱导下,非极性的乙烯分子和溴分子发生极化。
Mechanism of Bromination of an Mechanism of Bromination of an AlkeneAlkene
1)
+slow
+
R CH CH2 Br Br R CH CH2
Br _
2) +
R CH CH2
Br
+ Br: :.. _
..
anti-addition(stereospecific)
C C
Br
BrH
H
R
H
+ Br
+Br
HH
CYCLIC BROMONIUM IONCYCLIC BROMONIUM ION
note size ofbromine
环状溴鎓离子
HH
-Br
HH
Br
Br
Br+
BRIDGED BROMONIUM IONBRIDGED BROMONIUM ION
bridgingblocks approachfrom this side
Br
HH +
Br-
Br
H H+
Br-
Br
HH +
Br-
BRIDGED BROMONIUM IONBRIDGED BROMONIUM ION
resonance contributing structuresresonance contributing structures
symmetric ion -bromide ion couldadd to either sideleft or right
Br
H
H
Br
Br
H
H
BrH
Br
Br
H
ENANTIOMERS
symmetricintermediate
+
FORMATION OF ENANTIOMERSFORMATION OF ENANTIOMERS
Addition could also startfrom the top with bromideattacking the bottom.
2. 2. 烯烃与烯烃与 HXHX 加成加成
E+ = ElectrophileNu: = NucleophileGeneral Mechanism: The first step requires a powerful electrophile to attract the pi bond electrons, which then forms a carbocation. A nucleophile quickly adds to the carbocation to form the monosubstituted product.
-超共轭
3. 3. Markovnikov Rule and Markovnikov Rule and Stability of CarbocationStability of Carbocation
1)1) 极化极化
22 )碳正离子稳定性 )碳正离子稳定性
叔(叔( 33 。。)) >> 仲(仲( 2 2 。。 ) ) >> 伯(伯( 1 1 。。 ) ) >>CHCH33++
C CH CH2
H +
用 -p超共轭效应解释
C C CH2
H
H
H
COMPETING PATHWAYSCOMPETING PATHWAYS
lower energyintermediate
higher energyintermediate
rate-determininng(slow) step
rate-determining step
faster
slower
决速步骤
Hyperconjugation
C CH
H
HH
H
超共轭
CARBOCATION STABILITYCARBOCATION STABILITYHYPERCONJUGATION
CC
H..
H
H
+
R
R
electrons in an adjacent
C-H bond help to stabilizethe positive charge of thecarbocation by proximity(overlap)
CR
R
R+R CH R
+R CH2
+
tertiary secondary primary< <lowestenergy
highestenergy
碳正离子的稳定性
4. 4. 自由基加成自由基加成AntiAnti-- Markovnikov RuleMarkovnikov Rule
RCH CH2 + HBr RCH2CH2BrR2O2
Mechanism:RO OR 2RO¼ÓÈÈ
RCH CH2 + Br RCHCH2Br (1)
RO + H Br ROH + Br
( RCH CH2 + Br RCHBrCH2 (2)
RCHCH2Br + HBr RCH2CH2Br + Br
过氧化物效应
Problem AssignmentProblem Assignment
1.1. 乙烯与溴的氯化钠水溶液反应产物除乙烯与溴的氯化钠水溶液反应产物除了了 1,2-1,2- 二溴乙烷外,还有二溴乙烷外,还有 2-2- 溴乙醇溴乙醇和和 1-1- 氯氯 -2--2- 溴乙烷,为什么?溴乙烷,为什么?
2.2. 完成以下反应完成以下反应
F3CCH CH2 + HBr ?
Homework AssignmentHomework Assignment Pp75: 2.(1,3,6); 3(3,5); 5;6;8Pp75: 2.(1,3,6); 3(3,5); 5;6;8 提示(提示(
22 )()( bb ))为为 CHCH33CHCH22CHCH22OH;10;12OH;10;12 ((注注意为两步反应,第一步是慢反应,活化能高意为两步反应,第一步是慢反应,活化能高,第二步是快反应,活化能低),第二步是快反应,活化能低)
13;1513;15 提示要考虑超共提示要考虑超共
轭效应;轭效应; 1818 ;; 2020·´ Ó¦½ø³Ì
λÄÜ
¹ý ¶É̬1¹ý ¶É̬2
E1E2
H2C CH2 +Br2
CH2 CH2
Br+ Br-
BrCH2CH2Br