1. Organic Chemistry Chapter 221

2. Structure Determines Properties
Organic compounds all contain carbon
CO, CO2 , carbonates and carbides are inorganic
Other common elements are H, O, N, (P, S)
Carbon has versatile bonding patterns
Chains, rings, multiple bonds
Chain length nearly limitless
Carbon compounds generally covalent
Molecular; Gases, liquids or low melting solids; Varying solubilities; Nonconductive in liquid
C - C bonds unreactive (very stable) 2

3. Carbon Bonding
Carbon can bond to other carbon atoms in an almost infinite chain
Bond to a maximum of four other atoms
Carbon or other elements
Carbon with 4 single covalent bonds = tetrahedral
Carbon with 2 single & 1 double covalent bond = trigonal planar
Carbon with 1 single & 1 triple covalent bond = linear 3

4. Hydrocarbons Hydrocarbons contain only C & H Aliphatic hydrocarbons
Aliphatic or aromatic
Aliphatic hydrocarbons
Saturated or unsaturated aliphatics
Saturated = alkanes, unsaturated = alkenes or alkynes
Unsaturated have double or triple bonds
May be chains or rings
Ring molecules have two less H than chain so that ends can join
Chains may be straight or branched 4

5. Alkanes a.k.a paraffins Aliphatic General formula CnH2n+2 for chains
Very unreactive
Come in chains or/and rings
CH3 groups at ends of chains, CH2 groups in the middle
Saturated
Branched or Straight-Chain
Straight-chain = normal
Condensed formula has CH3 on each end and CH2 in middle 5

6. Condensed Structural Formulas
attached atoms listed in order
central atom with attached atoms
follow normal bonding patterns
use to determine position of multiple bonds
() used to indicate more than 1 identical group attached to same previous central atom
unless () group listed first in which case attached to next central atom 6

7. Structural Isomers
Isomers are molecules with the same molecular formula but different arrangements of the atoms
Different chemical and physical properties
Structural isomers are isomers in which the atoms are attached differently
Different bonding pattern
Different properties
a.k.a constitutional isomers 7

8. Naming each name consist of 3 parts prefix parent suffix
indicates position, number and type of branches
indicates position, number and type of each functional group
parent
indicates the length of the longest carbon chain or ring
suffix
indicates the type of hydrocarbon
ane, ene, yne
certain functional groups 8

9. Naming Alkanes
dec 10
non 9
oct 8
hept 7
hex 6
pent 5
Prefix
Number of Carbons
The first 4 alkanes are methane (C1), ethane (C2), propane (C3), butane (C4)
After that the names come from adding Greek prefix to –ane 9

10. Naming Alkanes Find the longest, continuous carbon chain
Number the chain from end closest to a branch
if first branches equal distance use next in
Name branches as alkyl groups
Branch name related to number of C
End in -yl
locate each branch by preceding its name with the carbon number on the chain
List branches alphabetically
do not count n-, sec-, t-, count iso
Use prefix if more than one of same group present
di, tri, tetra, penta, hexa
do not count in alphabetizing 10

11. Petroleum
Formed when ocean microorganisms died 500 million year ago, were buried, and subjected to large pressures
A dark, thick liquid composed mainly of hydrocarbons
Natural gas normally found with petroleum deposits
Mostly methane with some ethane, propane and butane
Petroleum separated into various fractions by distillation
Separation based on boiling point 11

12. Alkenes Aliphatic, unsaturated
Formula of chain alkenes - subtract 2 H from alkane formula for each double bond
C=C double bonds
Trigonal shape around C
Flat
No rotation
Cis - trans isomerism
Much more reactive than alkanes
Polyunsaturated = many double bonds 13

13. Naming Alkenes Naming Alkynes
change suffix on main name from -ane to -ene
number from end closest to double bond
number in front of main name indicates first carbon of double bond
Naming Alkynes
change suffix on main name from -ane to -yne
number from end closest to triple bond
number in front of main name indicates first carbon of triple bond 15

14. Alkynes Also known as acetylenes Aliphatic, unsaturated
Formula of chain alkynes - subtract 4 H from alkane for each triple bond
CC triple bond
Linear shape
No rotation
More reactive than alkenes 16

15. Aromatics Contain 1 or more 6 C unsaturated rings
Benzene rings
Chemical reactions different than alkenes
Burn sooty instead of clean
Undergo substitution instead of addition
Benzene
Liquid, BP = 80°C
All C-C bond lengths and bond angles identical
120°
Bond lengths between C-C and C=C
Planar molecule
Resonance hybrid 17

16. Naming Benzene Derivatives
main name either benzene or one of the common derivatives
ring numbered from position of main group or
2 = ortho (o), 3 = meta (m), 4 = para (p)
p-Cresol
m-Toluidine
o-Xylene
Anisole
Aniline
Phenol
Acetophenone
Benzaldehyde
Benzoic
Acid
Styrene
Cumene
Toluene C H 3 ( ) 2 O N 18

17. Functional Groups
In many organic compounds, C-to-H bonds are replaced by bonds to other atoms
C-Halogen, C-to-O, C-to-N, occasionally (C-to-S)
These compounds are generally considered hydrocarbon derivatives
Basically hydrocarbons with a few substitutions
These substituted bonds are more reactive than C-H bonds
Therefore, when molecules with the substituted bonds react, the reaction site is generally at the substituted bonds
These substituted atoms or groups of atoms are called functional groups, and they generally determine the chemical reactions an organic molecule will undergo
And also have influences on intermolecular attractions and therefore physical properties 19

18. Alcohols Naming Alcohols Have an –OH group in place of a H
Form H-bonds
To alcohol molecules and water
Solubility in water decreases as length of carbon chain increases
Common reactions include substitution for OH, elimination, oxidation
Naming Alcohols
Select the longest chain of carbon atoms containing the –OH group
Number the chain from the end closest to the –OH group
Determine the parent name from the number of C in the chain, replace the final -e with -ol
Name alkyl branches as usual 20

19. Classifying Carbons
Carbons in an organic molecule are classified based on the number of other carbons they are attached to
Primary Carbon, 1°, = carbon attached to one other carbon
Secondary Carbon, 2°, = carbon attached to 2 other carbons
Tertiary Carbon, 3°, = carbon attached to 3 other carbons
Quaternary Carbon, 4°, = carbon attached to 4 other carbons
Very unreactive
Hydrogens are classified based on carbon they are attached to
The hydrogens on a 1° carbon are called 1° hydrogens 21

20. Classifying Alcohols
alcohols are classified based on the carbon they are attached to
Primary Alcohol, 1°, = OH group on 1° C
Secondary Alcohol, 2°, = OH group on 2° C
Tertiary Alcohol, 3°, = OH group on 3° C 22

21. Aldehydes and Ketones Both contain C=O, carbonyl group
In ketones, the carbonyl group is attached to 2 carbon atoms
In middle of a chain or ring
In aldehydes, the carbonyl group is attached to a carbon and a hydrogen
Or 2 H in the case of formaldehyde
Must be on the end of a chain 23

22. Ketones
Often used as polar solvent when presence of OH cause problems
Acetone – R1 = R2 = CH3
Nail polish remover, paint solvent
MEK = methyl ethyl ketone – R1= CH3, R2 = CH2CH3
Paint solvent, gasoline additive
Aldehydes
Often strong odors, Used as fragrances and food additives
Formaldehyde – R1 = R2 = H
Gas, when dissolved in water = formalin
Suspected carcinogen
Used in the production of foams and adhesives
Acetaldehyde – R1 = H, R2= CH3 24

23. Naming Aldehydes Naming Ketones
Select the longest chain of carbon atoms containing the aldehyde group
Number the chain calling the carbonyl C position 1
Determine the parent name from the number of C in the chain, replace the final -e with -al
Name alkyl branches as usual
Naming Ketones
Select the longest chain of carbon atoms containing the carbonyl group
Number the chain from the end closest to the carbonyl group
Determine the parent name from the number of C in the chain, replace the final -e with -one 25

24. Carboxylic Acids Have carboxyl group, R1-COOH Always on end of chain
Acid functional group
Weak acid
Made by oxidation of 1° alcohols
under stronger conditions
Formic Acid, R1 = H
Bee and ant stings
Acetic Acid, R1 = CH3
vinegar 26

25. R1-COOH + R2-OH  R1-COOR2 + H2O
Esters
Replace acid H of carboxy group with R group, R1-COOR2
Sweet, fruity odors
Made by reacting carboxylic acid with an alcohol
R1-COOH + R2-OH  R1-COOR2 + H2O
Not like neutralization, alcohol not a base! 27

26. Naming Carboxylic Acids
Select the longest chain of carbon atoms containing the carboxy group
Number the chain calling the carboxy C position 1
Determine the parent name from the number of C in the chain, replace the final -e with –oic acid
Name alkyl branches as usual
Naming Esters
Select the longest chain of carbon atoms containing the ester group
Name R2 as alkyl group
Name R1 and carboxy C like acid except change the –ic ending to -ate
Put the pieces together, alkyl group first 28

27. Polymers Generally organic molecules Very large, molar masses 10,000+
Chain-like molecules made by linking together small molecules called monomers
Monomer units usually indicated in name with the prefix “poly-”
polyethylene, polypropylene, polystyrene 29

28. Linking Monomers
Addition Polymerization = monomers linked by each molecule attaching to chain by a synthesis type reaction
Condensation Polymerization = monomers linked when a reaction occurs that splits out a small molecule, like water
Homopolymers all monomer units alike
Copolymers have multiple monomer units 30