chemistry 2100 · 2015. 7. 31. · organic chemistry why is organic chemistry a separate discipline...
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Chemistry 2100
Chapter 10 and 11
Bloom’s Taxonomy
Richard C. Overbaugh, Lynn Schultz Old Dominion University
Student Objectives for this course
• Analyze and explain chemical differences among the various
classes of organic compounds • Evaluate carbohydrate structure and reactivity • Compare and contrast the four main classes of key
biomolecules • Explain the processes of protein folding and enzymatic
catalysis • Use knowledge of replication, transcription, and translation to
predict the outcome of genetic diseases • Relate biochemical concepts to digestion, metabolism, and
nutrition
Organic & Biological Chemistry
Organic Chemistry
Why is organic chemistry a separate discipline within chemistry?
Historical: Scientists at one time believed that a “vital force” present in living organisms was necessary to produce an organic compound. – The experiment of Wöhler in 1828 was the
first in a series of experiments that led to the demise of the vital force theory. 5!
VIIAVIAVA IV AII IA
II BIBVIIBVIBVBIV BII IBMg24. 31
12
O16. 00
8Ne20. 18
10F19. 00
9N14. 01
7B10. 81
5Be9.0 12
4Li6.9 41
3
He4.0 03
2IA
1
2
3
4
5
6
7
II A
VIII A
VIII B Na22. 99
11
H1.0 08
1
Al26. 98
13Si28. 09
14P30. 97
15S32. 07
16Cl35. 45
17Ar39. 95
18
K39. 10
19 20
40. 08Ca
21
44. 96Sc
22
47. 88Ti V
50. 94
23 24
52. 00Cr
25
54. 94Mn
26
55. 85Fe
27
58. 93Co
28
58. 69Ni
29
63. 55Cu
30
65. 38Zn
31
69. 72Ga
32
72. 59Ge
33
74. 92As
34
78. 96Se
35
79. 90Br
36
83. 80Kr
37
85. 47Rb
38
87. 62Sr Y
88. 91
39 40
91. 22Zr
41
92. 91Nb
42
95. 94Mo
43
(9 8)Tc
44
101.1Ru
45
102.9Rh
46
106.4Pd
47
107.9Ag
48
112.4Cd
49
114.8In
50
118.7Sn
51
121.8Sb
52
127.6Te I
126.9
53 54
131.3Xe
55
132.9Cs
56
137.3Ba
57
138.9La
58
140.1Ce
59
140.9Pr
60
144.2Nd
61
(1 45)Pm
62
150.4Sm
63
152.0Eu
64
157.3Gd
65
158.9Tb
66
162.5Dy
67
164.9Ho
68
167.3Er
69
168.9Tm
70
173.0Yb
71
175.0Lu
72
178.5Hf
73
180.9Ta W
183.9
74 75
186.2Re
76
190.2Os
77
192.2Ir
78
195.1Pt
79
197.0Au
80
200.6Hg
81
204.4Tl
82
207.2Pb
83
209.0Bi
84
(2 09)Po
85
(2 10)At
86
(2 22)Rn
87
(2 23)Fr
88
(2 26)Ra
89
(2 27)Ac
104
(2 61)Rf
105
(2 62)Db
106
(2 63)Sg
107
(2 62)Bh
108
(2 65)Hs
109
(2 66)Mt
110
(2 69)Uun
111
(2 72)Uuu
112
(2 77)Uub
114
(2 89)Uuq
116
(2 89)Uuh
118
(2 93)Uuo
90
232.0Th
91
(2 31)Pa U
238.0
92 93
(2 38)Np
94
(2 44)Pu
95
(2 43)Am
96
(2 47)Cm
97
(2 47)Bk
98
(2 51)Cf
99
(2 52)Es
100
(2 57)Fm
101
(2 58)Md
102
(2 59)No
103
(2 60)Lw
C612.01
C
General Chemistry
H 1 0 C 4 0 N 3 1 O 2 2 X 1 3
element covalent bonds lone pairs
~109.5°
H
CHH
H
x
x
x
C HxH
H
H
Valence Shell Electron Pair Repulsion Theory
4 tetrahedral 109.5° 3 trigonal planar 120° 2 linear 180°
regions of predicted predicted electron density geometry bond angles
~109.5°
• •
C N
H
HH
H
H
CCH
HH
H
120°
C CH H
180°
NC
HH
H••
120°
Meet the Elements
http://www.youtube.com/watch?v=Uy0m7jnyv6U
English Language Cursive
Shorthand
Type
The language of Chemistry
Molecular Formula
C2H6O
Structural Formula
Condensed Structural Formula
CH3CH2OH
3D Structural Formula
Molecular Representation
Skeletal, line-angle Formula
or
Alkanes
• Simplest hydrocarbons • Composed of only single bonds • Often referred to as aliphatic hydrocarbons
– From Greek aleiphar (fat or oil) • Also called Paraffins
– From Latin parum affinis (barely reactive)
• General formula: CnH2n+2
Methane & Ethane
H-C-HH
HH-C-C-H
H
H
H
H
Methane Ethane
Propane & Butane
CH3CH2CH2CH3CH3CH2CH3 CH3CH2CH2CH2CH3CH3CH2CH2CH3CH3CH2CH3 CH3CH2CH2CH2CH3PentaneButanePropane PentaneButanePropane
Condensedstructural
formula
Line-angleformula
Ball-and-stick model
Butane & Constitutional Isomers
CH3CH2CH2CH3 CH3CHCH3
CH3
Butane(bp -0.5°C)
2-Methylpropane(bp -11.6°C)
n-butane isobutane
C4H10
How many constitutional isomers?
C5H12 3 C6H14 5 C10H22 75
C20H42 366,319 C30H62 > 4 billion C40H82 > 65 trillion
C20H42 366,319 C30H62 > 4 billion C40H82 > 65 trillion
constitutional (structural) isomers
Naming Conventions: IUPAC Nomenclature
• International Union of Pure and Applied Chemistry
• Gives a set of unambiguous names • Despite this, common names are still used
Naming Alkanes
#C Prefix + -ane
C3 "prop" Gr., protos pion (first fat)* C4 "but" L., butyrum (butter) C5 "pent" Gr., pente (five) C6 "hex" Gr., hex (six) C7 "hept" Gr., hepta (seven) C8 "oct" L., octo (eight) C9 "non" L., nona (nine) C10 "dec" L., deca (ten)
C1 "meth" Gr., methy (wine)* C2 "eth" Gr., aithein (blaze)
Alkyl groups
-CH2CH3
-CH3
-CH2CH2CH3
-CHCH3CH3
-CH2CH2CH2CH3
-CH2CHCH3CH3
-CHCH2CH3CH3
-CCH3
CH3
CH3
tert-butyl
sec-butyl
isobutyl
butyl
isopropyl
propyl
ethyl
methylName
CondensedStructural Formula
CondensedStructural FormulaName
Naming Algorithm
(a) parent C-chain (b) substituents (c) numbers (d) alphabetical listing
Parent —Suffix
IUPAC Rules
Substituents—
Dreadful Details! • 1. The name for an alkane with an unbranched chain of
carbon atoms consists of a prefix showing the number of carbon atoms and the ending -ane.
• 2. For branched-chain alkanes, the longest chain of carbon atoms is the parent chain and its name is the root name.
• 3. Name and number each substituent on the parent chain and use a hyphen to connect the number to the name.
• 4. If there is one substituent, number the parent chain from the end that gives the substituent the lower number.
Dreadful details (part 2)! • 5. If the same substituent occurs more than once:
– Number the parent chain from the end that gives the lower number to the substituent encountered first.
– Indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so forth.
– Use a comma to separate position numbers.
• 6. If there are two or more different substituents – List them in alphabetical order. – Number the chain from the end that gives the lower number to the
substituent encountered first. – If there are different substituents at equivalent positions on opposite ends
of the parent chain, give the substituent of lower alphabetical order the lower number.
• 7. Do not include the prefixes di-, tri-, tetra-, and so forth or the hyphenated prefixes sec- and tert- in alphabetizing; – Alphabetize the names of substituents first, and then insert these prefixes.
Alkane Origins
Physical Properties of Alkanes
CH4CH3CH3CH3CH2CH3CH3(CH2)2CH3CH3(CH2)3CH3CH3(CH2)4CH3CH3(CH2)5CH3CH3(CH2)6CH3CH3(CH2)7CH3CH3(CH2)8CH3
methaneethanepropanebutanepentanehexaneheptaneoctanenonanedecane
Name
CondensedStructrualFormula
mp(°C)
bp(°C)
-182-183-190-138-130
-95-90-57-51-30
-164-88-42
0366998
126151174
(a gas)(a gas)(a gas)(a gas)0.6260.6590.6840.7030.7180.730
*For comparison, the density of H2O is 1 g/mL at 4°C.
Mol wt(amu)16.030.144.158.172.286.2
100.2114.2128.3142.3
Density of Liquid
(g/mL at 0° C)*
Physical Properties
Solubility: a case of “like dissolves like”. – Alkanes are not soluble in water because they are unable to
form hydrogen bonds with water. – Liquid alkanes are soluble in each other. – Alkanes are also soluble in other nonpolar organic
compounds, such as toluene and diethyl ether.
Density – The average density of liquid alkanes is about 0.7 g/mL; that
of higher-molecular-weight alkanes is about 0.8 g/mL. – All liquid and solid alkanes are less dense than water (1.0 g/
mL) and, because they are both less dense and insoluble, they float on water.
25!
Isomers and Physical Properties
pentane bp 36°C; mp -130°C
d 0.626 neopentane bp 9°C; mp -16°C
d 0.606
CH3 CH2 CH2 CH2 CH3
CH3 C CH3
CH3
CH3
CH3 CH
CH3
CH2 CH3
isopentane bp 28°C; mp -160°C
d 0.620
Alkane Origins
Gasoline, Combustion, & Octane Ratings
C6-C12 mixture
CH4 + 2O2 à CO2 + 2H2O + 212 kcal/mol
CH3CH2CH3 + 5 O2 à 3 CO2 + 4H2O + 530 kcal/mol
but…
2 CH3CH2CH3 + 7 O2 à 2 CO2 + 2 CO + 2 C + 8H2O + < 530 kcal/mol
Octane Rating – Controlled Explosions
2,2,4-trimethylpentane (iso-octane) Octane rating 100
Heptane Octane rating 0
Ethanol Octane rating 105
Octane Octane Rating -20
Reactions of Alkanes
Reaction with halogens (halogenation) – Halogenation of an alkane is a substitution
reaction.
29!
Halogenation
Perfluorodecalin
polytetrafluoroethylene (PTFE) Teflon
dichlorodifluoromethane Freon
dichlorodiphenyltrichloroethane DDT
http://www.youtube.com/watch?v=ACQr0IZIb5I
Cycloalkanes CnH2n
60° 90° 108° 120° 128° 135°
60° 88° 105° 109° 109° 109°
Interesting Cycloalkane Derivatives
Testosterone
Cholesterol
Estradiol
Muskone
Cyclohexane
Cyclohexane – the Chair
C
C
CC
C
C
1
2
3
5
6
4
"chair"
Cyclohexane Substituents
H
H
CH3
CH3
H
H H
H
1
6 5
4
3 (3)
(3') (1)
2
3
2
1
6 5
4
(3)
(3')
(1)
95% 5% 1,3-diaxial interactions
H
H
CH3
CH3
H
H H
H
1
6 5
4
3 (3)
(3') (1)
2
3
2
1
6 5
4
(3)
(3')
(1)
Geometric Isomers, a.k.a. cis-trans isomers
perspective Haworth
Cl
Cl
Cl Cl H
H H H
cis-1,2-dichlorocyclopentane
perspective Haworth
Cl
H
Cl H H
Cl H Cl
trans-1,2-dichlorocyclopentane
Cis/Trans Isomers
Cis: on the same side of the ring. Trans: on the opposite side of the ring,
– In drawing cis-trans isomers of disubstituted cyclopentanes, we can view a cyclopentane ring edge-on.
49!
Cis-Trans Isomers – Alternatively, we can view the cyclopentane ring from above.
Substituents are shown by solid wedges (above) or dashed wedges (below).
50!
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