Hydration硼氢化反应.docx
- 文档编号:6452149
- 上传时间:2023-01-06
- 格式:DOCX
- 页数:15
- 大小:560.02KB
Hydration硼氢化反应.docx
《Hydration硼氢化反应.docx》由会员分享,可在线阅读,更多相关《Hydration硼氢化反应.docx(15页珍藏版)》请在冰豆网上搜索。
Hydration硼氢化反应
Title:
Hydrationofalkenesbyhydroboration-oxidation:
preparationofoctan-1-olfrom1-octene
、
1.Introduction/Background:
Since1937,AmericanchemistHerbertCharlesBrownhadengagedinorganicboronchemistryandcompletedthefirstpaper(carbonylcompoundsreducedbydiborane)undertheguidanceofProfessorSchlesingeroftheUniversityofChicago.Afterthat,Brownnotonlyhasmadegreatachievementsintheorybutalsoinventeddozensofreducingagents.Hydroboration-oxidationreactionisalsofoundduringtheperiod.Brownwasawardthe1979NobelPrizeinChemistry.
BriefDescriptionoftheReaction.
Reductionreactionsbetweenboraneandunsaturatedbondsbelongtoelectrophilichydridetransfermechanism.
Boranecanbemadebysodiumboronhydrideandborontrifluoride.Diboraneisdimerofborane,toxicgases,typicallydissolvedintetrahydrofurantouse.Inetherliketetrahydrofuran,therearethefollowingequilibrium:
Inthisexperiment:
BMSwasused.
Boraneiselectrophilichydridetransferreducingagent.Itfirstlyattackelectron-richcenter.Itiseasytoreducecarboxylgroupandcanreactwithadoublebond.
2.Objectives:
1)ToobtaincertainknowledgeaboutthemechanismsofHydroboration-oxidationandDirectHydration
2)Tolearnhowtoidentifysimpleartefacts
3.ExperimentalData
Reagents:
M(Octene)=25mmol,
Mw(Octene)=8x12+16x1=96+16=112g/mol
m(Octene)=25mmolx112g/mol=2.8g
BMS:
M(BMS)=(1/3x25)x1.1=8.33x1.1=9.16mmol
BMS=H3BSMe=75.9g/mol
m(BMS)=9.16mmolx75.9g/mol=0.695g
V(BMS)=m(BMS)÷density=0.695g÷0.801g/ml=0.867ml
M=(trimethylamine–N-oxidedihydrate)=111.14g/mol
m(trim)=25mmolx111.14g/mol=2.7785g
M(octene)
MW(octene)
m(Octene)
M(BMS)
m(BMS)
V(BMS)
M(trim)
m(trim)
25mmol
112g/mol
2.8g
9.16mmol
0.695g
0.867ml
111.14g/mol
2.7785g
finalproduct:
theweightofroundbottomflask=62.22g
theweightofall=64.31g
theproduct=64.31g–62.22g=2.09g
M(product)=m(product)÷Mw(product)=2.09g÷130g/mol=16.07mmol
Yield%=16.07mmol÷25mmol=64.28%
4.Mechanism
DirectHydration
Hydroboration
Results
2-octanol
1-octanol
Themechanism
Markovniko’sRule
Anti-Markovniko’sRule
whentheelectrophilicadditionreaction(suchasareactionbetweenhydrogenhalidesandalkene),thepositivechargedgroup(suchasH+)oftheelectrophilicreagentisalwaysaddedtothecarbonthathasthemosthydrogen(leastsubstituted)andinthenegativechargedgroup(suchashalogen)isaddedtothecarbonthathastheleasthydrogen.(a)
theelectrophilicadditionreaction,thepositivechargedgroupoftheelectrophilicreagentisalwaysaddedtothecarbonthathastheleasthydrogenandinthenegativechargedgroupisaddedtothecarbonthathasthemosthydrogen.(b)
(a)Themechanismofdirecthydration:
Alkeneadditionreactionwithwaterusuallyneedacidtocatalyze.
●Generatingthecarboniumionsfirst,
●→andthencombinedwithwatertoformasalt,
●→finallyloseaprotontoformalcohols.
(b)Themechanismofhydroboration:
●Boronatomisintheabsenceofelectronsoitgetclosetothecarbonatomhasgreaterdensityofelectron.
●→Afterthat,theotherChaspositivecharge,thentheboronwantedtoreleaseHatomtoformcyclicfour-memberedtransitionstate
●→Finally,ittransformedintoRCH2CH2BH2.
Thereactionwillbeformedfor3timesuntiltheHconnectedtotheboronatomwasgone.
ThereactionshowsthatForasymmetricalkene,additionlocationfollowedbyanti-MarkovnikovRules.
(c)Oxidation:
●Firstly,borateisformed.
●Secondly,theborateishydrolysis.[Appendices1]
5.DiscussionandResults:
5.1IRanalysis
1.IRfor1-Octene
Wavenumbers(cm-1)
Typeofbond
Description
3079.60
C-Hstretch
Sharp,medium
2998.57
Sharp,strong
1642.37
C=Cstretch
Sharp.strong
994.49
C-Hbond
Sharpmedium
910.14
Sharp
2.IRforfinalproduct
Wavenumbers(cm-1)
Typeofbond
Description
3350.10
O-Hstretch
Borad,weak
2923.36
C-Hstretch
Sharpstrong
2854.80
Sharpstrong
AccordingtothestructureandIRofthe1-octanol,theO-H,C-OcanbefoundandtheO-Hwasalittleweakandboard.
AndtheC=C,C-Hbondhasgoneinthefinalproduct.
Soitcanbeconfirmedthatthe1-octanolwerepresentintheproduct.
5.2NMRanalysis
H-NMR
1-octene:
H-NMR&COSY
Thesmallpeakcanbeomittedatfirst.
Peak
Positionchemicalshift(ppm)
H2O
1.5307
Peak
Position(ppm)
Integration
Numberofhydrogen
Assignment
Peak
Descriptionofcoupling
Position
A
0.8846
3.1827
3
CH3-
D
Weak
H1
C
Weak
B
Strong
B
1.2785
6.3477
6
CH3-CH2CH2CH2
C
Strong
H2,H3,H4
C
1.3615
2.1435
2
-CH2-
D
Strong
H5
D
2,0225
2.1436
2
CH2-CH
NO
H6
E
4.9174
2.0300
2
CH=CH2
H8
4.9755
F
5.8197
1.0000
1
-CH
H7
1-Octanol
CDCl3=1H&D2O&COSY
Peak
Position(ppm)
Integration
Numberofhydrogen
+D2O
Assignment
Peak
Descriptionofcoupling
Position
A
0.8823
3.0055
3
Showed
CH3-
E
Weak
H1
C
Weak
B
Strong
B
1.3021
10.0273
10
Showed
CH2CH2CH2CH2CH2
E
Weak
H2,H3,H4,H5,H6
C
Strong
C
1.5472
2.0079
2
Showed
-CH2-
E
Strong
H7
D
1,7780
1.0602
1
Disappeared
-OH
E
Weak
H8
E
3.6271
2.0000
2
Showed
CH2-OH
H9
4.7573
0.2893
Showed
HOD
TheH-NMRthataddedD2OindicatethePositionof–OH.BecauseOHisactiveandthechemicalshiftisnotstable.D2Ocanreactwith–OHandproductHODwhichreplacethe–OH.
AfterHydration;
1)allthehydrogenatomsmovetodownfieldexpectCH3.
2)–CHdisappeared
3)OHappeared
1-Octene
C-NMR&DEPT
Peak
Position(ppm)
Depth135
Depth90
Assignment
Position
G
14.0866
Positive
Disappeared
CH3
C1
H
22.6459
Negative
Disappeared
CH2
C2orC3orC4orC5orC6
I
28.8509
Negative
Disappeared
CH2
J
28.9381
Negative
Disappeared
CH2
K
31.7590
Negative
Disappeared
CH2
L
33.8506
Negative
Disappeared
CH2
M
114.0729
Negative
Disappeared
CH2
C8
N
139.2525
Positive
Showed
CH
C7
InDepth90°,onlyCHbondwillbeshowed.
InDepth135°,CH2bondwillbedownwardpeakandCH3CHbondwillbeupwardpeak.
HSQC
CPeak
Hpeak
Descriptionofcoupling
Assignment
Position
G
A
Strong
CH3
C1
H
B
Strong
CH2
C3
B
Medium
I
B
Strong
CH2
C4orC5
C
Strong
CH2
J
B
Strong
CH2
C4orC5
C
Strong
CH2
K
B
Strong
CH2
C2
B
Weak
L
D
Strong
CH2
C6
HSQCtellsabouttherelationshipbetweenHandC.AlltheinformationwerematchedtheaboveCNMR,HNMR.
IJpeakswereverycloseandtheybothhavestrongcouplingwithBCpeakswhichrepresentH2,H3,H4,H5.ItishardtoidentifywhichcarbonatomtheIJpeakrepresents.
1-Octanol
C-NMR&DEPT
Peak
Position(ppm)
Depth135
Depth90
Assignment
Position
F
14.0779
Positive
Disappeared
CH3
C1
G
22.6357
Negative
Disappeared
CH2
C2orC3orC4orC5orC6orC7
H
25.7549
Negative
Disappeared
CH2
I
29.2840
Negative
Disappeared
CH2
J
29.4069
Negative
Disappeared
CH2
K
31.8201
Negative
Disappeared
CH2
L
32.7814
Negative
Disappeared
CH2
M
62.9905
Negative
Disappeared
CH2
C8
HSQC
Cpeak
Hpeak
Descriptionofcoupling
Assignment
Position
G
B
strong
CH2
C2orC3orC4orC5orC6
H
B
strong
CH2
I
B
Strong
CH2
J
B
Strong
CH2
K
B
Strong
CH2
L
C
Strong
CH2
C7
G,H,I,J,K,allhadstrongcouplingwithBpeakwhichmadetherecognitiondifficult.
AfterHydration
1)CHdisappeared
2)C7wenttohighfield.
TheDiglyme
H-NMR
Peak
Position(ppm)
Integration
NumberofH
Assignment
Postion
A
3.3826
6.0000
6
CH3-,CH3-
H1,H6
B
3.5556
3.9790
4
CH2-.CH2-
H2,H5OR
H3,H4
3.5647
3.5745
C
3.6426
4.0474
4
CH2-.CH2-
3.6615
C-NMR
Peak
Position
Depth135
Depth90
Assignment
D
58.9131
Positive
Disappeared
CH3
E
70.4740
Negative
Disappeared
CH2
F
71.8485
Negative
Disappeared
CH2
Thestructureofdiglymeissymmetry.Sothespectrumonlyshowed3peakswhichpresent2bondperpeak.
Thedifferencebetween1-octanoland2-octanolonH-NMR.C-NMR,IR
1-Octanol
2-Octanol
Structure
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2OH
CH3-CH2-CH2-CH2-CH2-CH2-CHOH-CH3
IR
Nodifferences,thesamebond
Nodifferences,thesamebond
H-NMR
Thereare6CH2bondinsimilarchemicalenvironment
NOCHandOHpeak
There5CH2bondinsimilarchemicalenvironment.
1CHand1OHpeak
C-NMR
Depth135°:
6negativepeaks,1positivepeaks
Depth135°:
5negativepeaks,2positivepeaks
Depth90°:
nopeak
Depth90°:
1CHpeak
Thecrudeproduct、
H-NMR
Peak
Position(ppm)
Integration
NumberofH
Assignment
Position
A
0.8827
3.1180
3
CH3
H1
B
1.2303
12.7927
12
CH2CH2CH2CH2CH2CH2
H2,H3.H4.H5.H6,H7
C
1.3313
1.6152
D
1.5394
0.9521
1
H-OH
water
E
3.3863
1.0015
1
-OH
H8
F
3.6412
2.0000
2
CH2-OH
H9
Comparedwiththepureproduct.,itcanbeidentifiedthatNoCHbondwereformedandonlyoneCH3bondwereformed.
→Only1-octanolwereformed.
C-NMR&COSY
Peak
Position(ppm)
Depth135°
Depth90°
Assignment
G
14.1059
Positive
Disappeared
CH3
H
22.6663
Positive
Disappeared
CH2
I
25.7502
Negative
Disappeared
CH2
J
29.3242
Negative
Disappeared
CH2
K
29.4036
Negative
Disappeared
CH2
L
31.8238
Negative
Disappeared
CH2
M
32.8194
Negative
Disappeared
CH2
N
58.4861
Positive
Disappeared
DiglymeCH3
O
63.1144
Negative
Disappeared
CH2
P
70.5628
Negative
Disappeared
DiglymeCH2
Q
71.9358
Negative
Disappeared
DiglymeCH2
TheC-structuredidn’tchange.
→Sonoex
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Hydration 氢化 反应