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10.1 Structure and Nomenclature
1. Nomencature of alcohols
CH3OH
Methanol(methyl alcohol)
CH3CH2OH
Ethanol
(ethyl alcohol)
a 1o alcohol Ò»¼¶´¼
CH3CHOHCH3
2-Propanol
(Isopropyl alcohol)
a 2o alcohol ¶þ¼¶́¼
(CH3)3COH
2-Methyl-2-propanol
(tert-butyl alcohol)
a 3o alcoholÈý¼¶´¼
A hydroxyl group attached to a saturated carbon atom
Alcohols (ROH) react with phosphoric acid (H3PO4) to yield alkyl phosphates
HO P
OH
O
OH+ P
OH
O
OH
Ethyl dihydrogen phosphateÁ×Ëá¶þÇâÒÒõ¥
CH3CH2OH
Phosphoric acid
CH3CH2O
CH3CH2OHP
OH
O
OCH2CH3
Diethyl hydrogen phosphateÁ×ËáÇâ¶þÒÒõ¥
CH3CH2OCH3CH2OH
P
OCH2CH3
O
OCH2CH3CH3CH2O
Triethyl phosphateÁ×ËáÈýÒÒõ¥
10.13 Conversion of alcohols into alkyl halides
Alcohols react with a variety of reagents to yield alkyl halides. The most commonly used reagents are hydrogen halides (HCl, HBr, or HI), Phosporous tribromide (PBr3), and thionly chl
10.14 Alkyl halides from the reactions of alcohols with
hydrogen halides
R OH HX+ R X + H2O
(NaX + H2SO4)
The order of reactivity of the hydrogen halides is: HI HBr HCl
The order of reactivity of alcohol is: R3COH 3o R2CHOH 2o ROH 1o
10.14A Mechanisms of the reactions of alcohols with
HXH3C
CH3
CH3
OH + HCl (cond) H3C
CH3
CH3
OHH
+Step 1
fastCl-+
SN1 type reaction
Step 2 H3C
CH3
CH3
OHH
+ slowH3C
CH3
CH3
+ + H2O
SN1 type reaction
Step 3 H3C
CH3
CH3
+ + Cl- H3C
CH3
CH3
Clfast
酸 (H+) 和 Lewis acid (ZnCl2) 促进此反应。
10.15 Alkyl halides from the reactions of alcohols with PBr3
or SOCl2
3R OH
(1o or 2o)
+ PBr3 3 RBr + H3PO3
RCH2OH + Br P
Br
Br RCH2O
H
+P Br
Br
+ Br-
O
H
+P Br
Br
Br- +
Step 1
Step 2 RCH2 RCH2Br + HOPBr2
SN2 reaction
A good leaving group
3R OH
(1o or 2o)
+ SOCl2 3 RCl + SO2 + HCl
thionyl chloride
refluxadd R3N or Pyridine to the mixture to promote the reaction by reacting with the HCl
Step 2 RCH2O
H
+S Cl
O-
Cl
RCH2O S Cl
O
+ HCl
Alkyl chlorosulfite
RCH2OH + Cl S
O
Cl RCH2O
H
+S Cl
O-
Step 1
Cl
O S Cl
O
Cl- + RCH2 RCH2Cl + O=S=O + Cl-SN2 reaction
A good leaving group
Step 3
Alkyl chloride
10.16 Synthesis of ether 醚的合成
10.16A Ethers by intermolecular dehydration of alcohols ( 醇的分子间脱水制醚)
ROH + HORH+
ROR + H2O
CH3CH2OH
CH2=CH2 + H2O
CH3CH2OCH2CH3 + H2O
Ethene
Diethyl ether
H2SO4
180oC
H2SO4
140oC
10.16B The Williamson synthesis of ethers ( 醚的威廉姆孙合
成)An important route to unsymmetrical ethers is a nucleophilic substitution reaction
known as the Williamson synthesis.
RONa + R' L
L = Br, I, OSO2R'', or OSO2OR''
SN2 reactionROR' + NaL
Sodium alkoxide
How to synthesis of ethyl propyl ether (CH3CH2CH2OCH2CH3)
CH3CH2CH2OH + Na
Propyl alcohol
CH3CH2CH2ONa
Sodium propoxide
+ 1/2 H2
CH3CH2CH2ONa + CH3CH2 ISN2 reaction
CH3CH2CH2OCH2CH3 + NaI
The Williamson synthesis
10.16C tert-Butyl ethers by alkylation of alcohols
HOCH2CH2CH2Br + NaC
3-Bromo-1-propanol
NaOCH2CH2CH2Br + HCCH CH
HOCH2CH2CH2C CH HOCH2CH2CH2Br + NaC
3-Bromo-1-propanol
CH
3-Bromo-1-propanol
HOCH2CH2CH2Br+CH2=C(CH3)2 (CH3)3COCH2CH2CH2Br
Éú³ÉÃѱ£»¤´¼ôÇ»ù
NaC CH
SN2 reaction(CH3)3COCH2CH2CH2 C CH
H+, H2OHOCH2CH2CH2C CH
È¥±£»¤»ù
10.16D Trimethylsilyl ethers. Silylation
(三甲硅醚 --- 甲硅烷基化作用)
A hydroxyl group can also be protected in neutral or basic solutions by converting it a trimethylsily ether group, -OSi(CH3)3. This reaction, called silylation, is done by allowing the alcohol to react with chlorotrimethylsilane in the prese
nce of a tertiary amineROH + (CH3)3SiCl ROSi(CH3)3
ChlorotrimethylsilaneÂÈ»¯Èý¼×»ù¹è
Éú³É¹èÃѱ£»¤´¼ôÇ»ù
+ HCl(CH3CH2)3N
ROH + (CH3)3SiCl ROSi(CH3)3
ChlorotrimethylsilaneÂÈ»¯Èý¼×»ù¹è
Éú³É¹èÃѱ£»¤´¼ôÇ»ù
+ HCl(CH3CH2)2N
È¥±£»¤»ùROSi(CH3)3
H+ , H2O ROH + (CH3)3SiOH
Synthesis of HOCH2CH2CH2C CH
3-Bromo-1-propanol
HOCH2CH2CH2Br+(CH3)SiCl (CH3)3SiOCH2CH2CH2Br
Éú³É¹èÃѱ£»¤´¼ôÇ»ùNaC CH
SN2 reaction(CH3)3SiOCH2CH2CH2C CH
H+, H2OHOCH2CH2CH2C CH
È¥±£»¤»ù
(CH3CH2)3N
10.17 Reactions of ethers
Heating dialkyl ethers with very strong acids (HI, HBr, and H2SO4) cause them to undergo reactions in which the carbon-oxygen bond breaks. Diethyl ether, for example, react with hot concentrated hydrobromic acid to give two molar equivalents of