Organic Chemistry The chemistry of carbon and carbon-based compounds.
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Transcript of Organic Chemistry The chemistry of carbon and carbon-based compounds.
Organic Chemistry
The chemistry of carbon and carbon-based compounds
Carbon is unique amongthe elements because:
it can have up to four bonds per C atom --
single, double, or triple bonds
--
--
it can form REALLY long chains of C atoms
its bonds are strong
–C–C– C=C –C=C–
Why is carbon so special?
Organic ChemistryOrganic Chemistry is everywhere!Smells & tastes fruits, chocolate, fish, mint
Medications Aspirin, Tylenol, Decongestants, Sedatives
Addictive substances Caffeine, Nicotine, Alcohol, Narcotics
Hormones/Neurotransmitters Adrenaline, Epinephrine
Food/Nutrients Carbohydrates, Protein, Fat, Vitamins
Genetics DNA, RNA
Consumer products Plastics, Nylon, Rayon, Polyester
Drawing Organic Structures
Butane: C4H10
C C C C
H
H
H
H
H
H
H
H
H
H
CH3 CH2 CH2 CH3
CH3CH2CH2CH3
CH3(CH2)2CH3
Shortcuts make structures easier & faster to draw
Line Structure• Only shows bonds• C atoms assumed at each end
and intersection of bonds• H atoms not shown• Assume 4 bonds to each C• Fulfill C’s 4 bonds by adding H’s
Lewis Structure
Condensed Structures
Carbon Atoms
Practice Drawing Structures
Formula Lewis Condensed Line
C2H6CH3CH3
C3H8CH3CH2CH3
C5H12CH3CH2CH2CH2CH3
or CH3(CH2)3CH3
C6H14CH3CH2CH2CH2CH2CH3
or CH3(CH2)4CH3
Types of Organic CompoundsClassified according to functional groups
Alkane
Alkene
Alkyne
Haloalkane
Alcohol
Ether
Ketone
Aldehyde
Carboxylic acid
Amine
Amino acid
AmideO
H
O
NH2
O
OH
O
H2NOH
O
OH
Cl
Br
NH2
C C
O
Big Idea in Organic Chemistry
Structure controls Function
Each functional group has predictable reactivity
Naming Alkanes (or Paraffins)• Made only of C and H
• All C atoms are tetrahedral(only C-C single bonds)
• General formula = CnH2n+2
(CH4, C2H6, C3H8, C4H10,
etc.)
• Alkanes are named based on the number of carbons in the longest chain!
Naming Basic Alkanes
Alkane Alkyl substituents# of
C atoms
CH4
CH3CH3
CH3CH2CH3
CH3CH2CH2CH3
-CH3
-CH2CH3
-CH2CH2CH3
Methyl
Ethyl
Propyl
etc.
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Root: number of C atomsSuffix: functional group (-ane for alkanes) (-yl for alkyl groups)
1
2
3
4
5
6
7
8
9
10
Linear vs. Branched Alkanes• General formula = CnH2n+2 (CH4, C2H6, C3H8, C4H10)
• Can have linear or branched alkanes
C5H12
• Same molecular formula, different structure: structural isomers
• Branches, including other atoms bonded, are called substituents. Common non-carbon ones are:
C CH2H3C
H
CH3
CH3
–NO2 –NH2 –F –Br –I nitro amino fluoro bromo iodo
Naming Branched Alkanes (IUPAC)
1. Root name: name of longest continuous C chain (parent chain)• Two equally long? Choose the one with more branches
2. Number C atoms in chain, starting at end with first branch
3. Identify substituents, give each a number (C it is connected to)• Two or more identical substituents: use prefixes (di-, tri-, tetra-, etc.)
4. List substituents alphabetically before root name• Do not alphabetize prefixes
5. Punctuation: commas separate numbers from each otherhyphens separate numbers from namesno space between last substituent & root name
4-ethyl-3,5-dimethyloctane1
2
3
65
8
74
4-ethyl
3-methyl and 5-methyl = 3,5-dimethyl
Octane
Provide each counterpart.
4-ethyl-2-methylhexane
octane
1
2
3
4
5
6
7
8
5-ethyl-3-methyl
(C11H24)
(C9H20)
Naming Alkanes Practice
a. 2,4-dimethylpentane
b. 2,4-dimethylhexane
c. 2,4,6-trimethylheptane
d. 3-ethyl-2-methylpentane
e. 2,3-dimethylpentane
f. 2,2-dimethylhexane
g. 2,5-dimethylhexane
h. 4-methylheptane
IsomersThe fat dog shook himself, and then rolled over on the wet rug.
The dog shook the fat rug, then rolled over and wet on himself.
These two statements use the same words...but have very different meanings!
OR
Likewise, isomers may have the same formula, but have very different structures…
Structural Isomer Practice• On piece of your own paper, draw AND name
ALL of the isomers for the following alkanes:
Formulas # isomers
If you complete that, try to draw and name all of the isomers for octane (C8H18) in your HW. There are 18 of them!
Some of your drawings may look different, but they are only different structures (isomers) if they also have different names
C5H12
C6H14
C7H16
359
Structural Isomers: C5H12
pentane
2-methylbutane
2,2-dimethylpropane
Structural Isomers: C6H14
hexane
2-methylpentane
3-methylpentane
2,3-dimethylbutane
2,2-dimethylbutane
Structural Isomers: C7H16
heptane
2-methylhexane
3-methylhexane
2,2-dimethylpentane
2,3-dimethylpentane
Structural Isomers: C7H16
2,4-dimethylpentane
3,3-dimethylpentane
3-ethylpentane
2,2,3-trimethylbutane
1 23
4 56
Naming Practice
F ClF
Cl
IBr
Cl
Br
5-chloro-2-fluorohexane
2-chloro-5-fluorohexane 2-chloro-4-fluoro-2,3-dimethylpentane
2-bromo-3-ethyl-4-iodopentane 2-bromo-4-chloro-3-isopropylpentane
Two equal numbering options? Number based on alpha order
12
34
5
6
Provide each counterpart.
3-bromo-2-chlorohexane
heptane
2-methyl-1-nitrobutane
heptane2-amino-6-nitro-3-propyl
2-ethyl-1,1-diiodo I
I
Cl
Br
NO2
NH2 NO2
Structural Isomers
What are the possible structural isomers of C3H7Br?
BrBr
1-bromopropane 2-bromopropane
What are the possible structural isomers of C4H9Cl?
Cl
Cl
Cl
Cl
1-chlorobutane
2-chlorobutane
2-chloro-2-methylpropane
1-chloro-2-methylpropane
Cycloalkanes• Alkanes with closed ring(s) of C atoms• General formula: CnH2n (C3H6, C4H8, C5H10, etc.)• Naming: use cyclo- prefix before alkane name
cyclopropanen = 3
cyclopentanen = 5
cyclobutanen = 4
cyclohexanen = 6
Naming substituted cycloalkanes:• 1 substituent: no numbering necessary• 2 or more substituents: lowest numbering scheme, then
by alphaCH3
methylcyclopentane
CH3
Cl 1-chloro-3-methylcyclohexane
C3H6 C4H8 C5H10 C6H12
1-chloro-5-methylcyclohexane
Fun Common Names
boxanewindowpane
basketane
brokenwindowpane
Teepane