Lecture 65 Organic Chemistry I

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Lecture 65 - Organic Chemistry I
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• synthetic fibres
• plastics
• artificial sweeteners
• drugs
• coal, petroleum

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Organic Chemistry

• originally meant chemistry of organisms
• now means chemistry of
• C - containing compounds
• (but not CO2, H2CO3, etc.)

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Organic Chemistry

• organic compounds once thought to have a life
  force until 1828...

ammonium cyanate
urea
(inorganic)
(organic)
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Organic Chemistry

• Whats so special about C?

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Organic Chemistry

• Whats so special about C?
• - it bonds to itself
• long chains
• ring structures
• - it bonds to H, N, O, S, halogens, etc.

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Organic Chemistry

• C living things
• as
• Si rocks

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Organic Compounds

• 107 compounds known so far
• 90 of them are organic

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Hydrocarbons

• made only of C, H
• most other organic compounds are derivatives of
  hydrocarbons

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Hydrocarbons
Methane, CH4
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Alkanes

• general formula CnH2n2
• alkanes are saturated
• (each C is bound to 4 other atoms)

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Alkanes Saturated Hydrocarbons
H
H
H
H
C C
H2(g)
H - C - C - H(g)
H
H(g)
H
H
Saturated
Unsaturated
(Ethane)
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saturated vs. unsaturated fatty acids
O
OH
O
OH
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Alkanes Saturated Hydrocarbons

• CH4 methane natural gas
• C2H6 ethane making ethylene
• C3H8 propane heating, barbecues
• C4H10 butane lighter fluid
• C5H12 pentane solvent
• C6H14 hexane part of gasoline
• then heptane, octane, nonane, decane

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Isomers
methane 1 isomer
ethane 1 isomer
propane 1 isomer
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Isomers
normal butane (n-butane)
isobutane
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Drawing Structures
n-butane
CH3CH2CH2CH3
single bonds
isobutane
CH3CHCH3CH3
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Drawing Structures

• Draw all the isomers of pentane (C5H12)

1. CH3 - CH2 - CH2 - CH2 - CH3
(n-pentane)
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1. CH3 - CH2 - CH2 - CH2 - CH3
(n-pentane)
CH3
2. CH3 - CH - CH2 - CH3
(isopentane)
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2. CH3 - CH - CH2 - CH3
(isopentane)
CH3
3. CH3 - C - CH3
(neopentane)
CH3
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Equivalent Structures
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Nomenclature

• a systematic naming system
• e.g.

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Nomenclature
6 carbons
1. Find the longest continuous chain of
carbon atoms this is a hexane
2. Alkane groups as substituents are named as
follows
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Alkyl Groups

• - CH3 methyl
• - CH2CH3 ethyl
• - CH2CH2CH3 propyl
• CH3CHCH3 isopropyl

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• - CH2CH2CH2CH3 butyl
• CH3CHCH2CH3 sec-butyl
• - CH2 - C - CH3 iso-butyl
• - C - CH3 tert-butyl

H
CH3
CH3
CH3
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CH3
6
CH2
5
CH2
4
CH3 - CH2 - CH - CH2 - CH3
2
1
3
ethyl
hexane
3. Number the long chain so that the
substituents are at the lowest numbers
3-ethylhexane
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other examples
pentane
methyl
2-
4
2
3
5
1
pentane
2,4-
dimethyl
2,2,4-trimethylpentane
(isooctane, octane rating 100)
4
2
3
5
1
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other examples
4-ethyl-3,5-dimethylnonane
4
1
9
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other examples
4-tert-butylheptane
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Cycloalkanes

cyclopropane
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Cycloalkanes
cyclobutane
cyclopentane
cyclohexane