ALKANE1-student. matriculation
-
Upload
wafiy-yoshioka -
Category
Documents
-
view
227 -
download
0
Transcript of ALKANE1-student. matriculation
-
7/29/2019 ALKANE1-student. matriculation
1/47
HYDROCARBONS
-
7/29/2019 ALKANE1-student. matriculation
2/47
Learning Outcome
Explain terms saturated and unsaturated HC
Describe alkanes
Drawing alkanes and its nomenclature-straight, branched chain, cyclic
-
7/29/2019 ALKANE1-student. matriculation
3/47
HYDROCARBONHydrocarbon are compoundswhich contain only carbonand
hydrogen atoms.
-
7/29/2019 ALKANE1-student. matriculation
4/47
ALKANES(saturated)
contain onlysingle bond
ALKENES(unsaturated)
containC=C
CYCLO-ALKANES (saturated)Alkanes which C atoms are
join in rings
ALKYNES(unsaturated)
contain
CC
CYCLO-ALKENES(unsaturated)
HYDROCARBONS
AROMATIC(contain one or more benzene ring)
ALIPHATIC(chain structure)
-
7/29/2019 ALKANE1-student. matriculation
5/47
Saturated hydrocarbons
- compound with C-C
- Example : alkanes and cycloalkanes
Contain the maximum number of hydrogen
atoms that the carbon compound canpossess.
-
7/29/2019 ALKANE1-student. matriculation
6/47
Unsaturated hydrocarbons
-compounds with multiple bonds
-Example : alkenes, cycloalkenes, alkynes
and aromatic hydrocarbons
They posses fewer than the maximum
number of hydrogen atoms.
-
7/29/2019 ALKANE1-student. matriculation
7/47
ALKANES
Alkanes are known as saturatedhydrocarbon which contain only singlecovalent bonds.
General formula for straight chain ofalkanes isCnH2n+2
where n
1General formula for cycloalkanes isCnH2nwhere n 3
-
7/29/2019 ALKANE1-student. matriculation
8/47
Each carbon atom in alkanes is
- sp3 hybridised- tetrahedral with four sigma bond (formed
by the four sp3 hybrid orbitals.)
- all bond angles are close to 109.5o
Alkanes IUPAC names have the ane
suffix.
-
7/29/2019 ALKANE1-student. matriculation
9/47
The First Ten Unbranched Alkanes
Molecular
formula
Structural formula No .of C
atoms
Name
CH4 CH4 1 Methane
C2H6 CH3CH3 2 Ethane
C3H8 CH3CH2CH3 3 Propane
C4H10 CH3(CH2)2CH3 4 Butane
C5H12 CH3(CH2)3CH3 5 Pentane
C6H14 CH3(CH2)4CH3 6 Hexane
C7H16 CH3(CH2)5CH3 7 Heptane
C8H18 CH3(CH2)6CH3 8 Octane
C9H20 CH3(CH2)7CH3 9 Nonane
C10H22 CH3(CH2)8CH3 10 Decane
-
7/29/2019 ALKANE1-student. matriculation
10/47
C C C
H
H
H
H
H
H
H
H
C C C C
H
H
H
H
H
H
H
H
H
H
C C C C
H
H
H
H
H
H
H
C
H
H
H
H
H
H
C
H
H H
C C
H
H
H
H
H
H
-
7/29/2019 ALKANE1-student. matriculation
11/47
Starting from C4H10 onwards,the alkanes show thephenomenon of chain
isomerism.
They can exist as linear OR
branched alkanes.
-
7/29/2019 ALKANE1-student. matriculation
12/47
Example
C4H10
CH3(CH2)2CH3 CH3CH(CH3)2
2-
isobutane
-
7/29/2019 ALKANE1-student. matriculation
13/47
C5H12
-
7/29/2019 ALKANE1-student. matriculation
14/47
IUPAC NOMENCLATURE
IUPAC International Union ofPure and Applied Chemistry
Branched - chain alkanes arenamed according to the following
rules:
-
7/29/2019 ALKANE1-student. matriculation
15/47
Choose the longest continuous chain ofcarbon atoms; this chain determines theparent name for alkanes.
Examples:
CH3CH2CH2CH2CH2CH3
Parent name: hexane
-
7/29/2019 ALKANE1-student. matriculation
16/47
Parent name : heptane
CH2CH2CH2CH2CH3
CH2
CH3
-
7/29/2019 ALKANE1-student. matriculation
17/47
Number the longest chain beginningwith the end of the chain nearer thesubstituent.
CH3CH2CH2CH2CHCH3
Example:
CH3 substituent
16 4 235
-
7/29/2019 ALKANE1-student. matriculation
18/47
CH3CH2CH2CH2CH|
CH2|CH3
substituentCH3
1
2
34567
-
7/29/2019 ALKANE1-student. matriculation
19/47
Use rule number 2 to locate the positionof the substituent.
The position (that is number) and thename of the substituent must be
written in front of the parent chain.
-
7/29/2019 ALKANE1-student. matriculation
20/47
CH3CH2CH2CH2CHCH3
Examples:
CH3
2-methylhexane
16 4 235
Substituent
-methyl at C-2
-
7/29/2019 ALKANE1-student. matriculation
21/47
CH3CH2CH2CH2CHCH3|
CH2|CH3
3-methylheptane
1
2
34567
Substituent-methyl at C-
3
-
7/29/2019 ALKANE1-student. matriculation
22/47
butyl
isopropyl
propyl
ethyl
methyl
SubstituentName
CH3
CH2CH3
CH2CH2CH3
CHCH3
CH3
CH2CH2CH2CH3
Some Common Substituent Groups
Alkane
methane
propane
butane
ethane
-
7/29/2019 ALKANE1-student. matriculation
23/47
isobutyl
sec-butyl
tert-butyl
neopentyl
CH2CHCH3
CH3
CHCH2CH3
CH3CH3
CH3
CCH3
CH3
CH2CCH3
CH3
-
7/29/2019 ALKANE1-student. matriculation
24/47
cyclopropyl
cyclobutyl
phenyl
benzyl
C6H5 or
CH2
-
7/29/2019 ALKANE1-student. matriculation
25/47
Name Substituent
Bromo -Br
Chloro -Cl
Flouro -F
Iodo -I
Hydroxyl -OH
Amino -NH2
Cyano -CN
Nitro -NO2
-
7/29/2019 ALKANE1-student. matriculation
26/47
Iftwo ormore substituents are present,give each substituent a numbercorresponding to its location on the longest
chain.
the substituent should be listedalphabetically.
In alphabetizing, the prefixes di, tri,tetra, sec-, tert- are ignoredexcept iso
and neo.
-
7/29/2019 ALKANE1-student. matriculation
27/47
Example:
1 2 3 4 5 6CH3CHCH2CHCH2CH3
| |
CH3 CH2|
CH3
4-ethyl-2-methylhexane
-
7/29/2019 ALKANE1-student. matriculation
28/47
Iftwo substituents are present on thesame carbon atom, use that numbertwiceExample:
CH3
|3 4 5 6CH3CH2CCH2CH2CH3
|2
CH2|
1CH3
3-ethyl-3-methylhexane
-
7/29/2019 ALKANE1-student. matriculation
29/47
~If two or more identical substituents arepresent, use prefixes di-(2 identical substituents),tri-(3 identical substituents), tetra-(4 identicalsubstituents).
~ Commas are used to separate numbers fromeach other.
Example:CH3CHCH CH3
| |
CH3
CH3
2,3-dimethylbutane
-
7/29/2019 ALKANE1-student. matriculation
30/47
If there are two chains of equal lengthas the parent chain, choose the chain
with the greater number ofsubstituents.
-
7/29/2019 ALKANE1-student. matriculation
31/47
7 6 5 4 3 2 1
2,3,5-trimethyl-4-propylheptane
(four substituents)
CH3CH
2-CH CH CH CHCH
3
| | | |CH
3CH
2CH
3CH
3
|
CH2
|
CH3
4 3 2 1
5
6
7
4-sec-butyl-2,3-dimethylheptane
(three substituents)
-
7/29/2019 ALKANE1-student. matriculation
32/47
If branching occurs at an equal distance fromeither end of the longest chain, choose the
name that gives the lower number at thefirst point of difference.
6 5 4 3 2 1CH
3CHCH
2CH CHCH
3
| | |
CH3 CH3 CH3
2,3,5-trimethylhexane
(NOT 2,4,5-trimethylhexane)
1 2 3 4 5 6
-
7/29/2019 ALKANE1-student. matriculation
33/47
CYCLOALKANES
Cycloalkanes
alkanes which carbon atomsare joined in rings.
Cycloalkanes are known as saturatedhydrocarbon, because it has the maximumnumber of bonded hydrogen ( only has single
bonds).
General formula:
CnH2n where n = 3, 4, 5,
-
7/29/2019 ALKANE1-student. matriculation
34/47
NOMENCLATURE OF
CYCLOALKANES
Cycloalkanes with only one ring arenamed with the prefix cyclo- to the names
of the alkanes (contain the same number
of carbon atoms)
-
7/29/2019 ALKANE1-student. matriculation
35/47
Monocyclic compounds
C3H6 cyclopropane
C4H8 cyclobutane
C5H10 cyclopentane
-
7/29/2019 ALKANE1-student. matriculation
36/47
If only one substituent is present, it is notnecessary to designate its position.
Examples:
CH3
Chlorocyclopropane
Methylcyclohexane
Cl
-
7/29/2019 ALKANE1-student. matriculation
37/47
Iftwo substituents are present, numbercarbon in the ring beginning with the
substituent according to the alphabeticalorder
and
number in the direction that gives the nextsubstituent the lowest number possible.
-
7/29/2019 ALKANE1-student. matriculation
38/47
Examples:
1-ethyl-2-methylcyclohexaneNOT
1-ethyl-6-methylcyclohexane
CH3
CH2CH31
23
4
5 6
-
7/29/2019 ALKANE1-student. matriculation
39/47
1,3-dichlorocyclopentane
(NOT 1,5-dichlorocyclopentane)
Cl Cl1
2
3
4 5
-
7/29/2019 ALKANE1-student. matriculation
40/47
When three ormore substituents arepresent, begin at the carbon with
substituent that leads to the lowest setof locants.
-
7/29/2019 ALKANE1-student. matriculation
41/47
Example:
CH2CH3
1-chloro-3-ethyl-4-methylcyclohexane
4- chloro-2-ethyl-1-methylcyclohexane
Cl CH3
Locants
chloroethyl
methyl
1
3
4 1
2
4
1
2 3
4
56
1
23
4
5 6
-
7/29/2019 ALKANE1-student. matriculation
42/47
1-ethyl-1,3-dimethylcyclopentane(NOT 3-ethyl-1,3-dimethylcyclopentane)
H3C CH2CH3
CH3
-
7/29/2019 ALKANE1-student. matriculation
43/47
When a single ring system is attachedto a single chain with a greater numberof carbon atoms
orwhen morethanone ring systemisattached to a single chain, then it is
appropriate to name the compounds as
cycloalkylalkane.
Number of C at ring
Number of C at
linear chain
-
7/29/2019 ALKANE1-student. matriculation
44/47
1,3-dicyclohexylpropane
1
2
3
cycloalkyl alkane
-
7/29/2019 ALKANE1-student. matriculation
45/47
Examples:
CH2CH
2CH
2CH
2CH
3
1-cyclobutylpentane
-
7/29/2019 ALKANE1-student. matriculation
46/47
CH CH3
CH3
CH2CH3
Name the following compounds according to IUPAC
nomenclature
CH3
CH2
CHCH2
CH3
CHCH
3CH3
CH3
C CH2
CH2
CH3
CH
CH3
CH3
CH3
CH3
CH CH2
CH CH
C2
H5
CH3
C2
H5
CH
CH3
CH3
CH3
CH2
CH3
CH3
CH3
CH2
CH3
CH3
Br
D th t t f h f th
-
7/29/2019 ALKANE1-student. matriculation
47/47
Draw the structure for each of the
following compounds
(a) 1,1-dichloro-3-methylcyclohexane(b) 2,2-dimethyl-3-cyclohexylbutane
(c) 1-bromo-5-chloro-3-ethyl-3-methylpentane]
(d) 5-sec-butyl-2,4-dimethylnonane