1. The chemistry of carbon
Unit 8: Organic Chemistry
The chemistry of carbon

2. Organic compounds contain carbon
Properties of organic compounds
1. most are insoluble in water
(non-polar)
2. most have low melting
(weak intermolecular forces)
and boiling points
3. most are non-electrolytes
(covalent bonds)
4. most reactions are slow
(strong covalent bonds)

3. ALWAYS!!! The Carbon Atom -- has 4 valence electrons
-- makes 4 covalent bonds
ALWAYS!!!
tetrahedron
In the structural formula, shared electron pairs are shown by a dash
-- can form double and triple bonds

4. Other atoms often found in organic compounds:
H – 1 bond
O – 2 bonds
N – 3 bonds
halogens – 1 bond
Some compounds have the same molecular formula, but different
structural formulas
Example: C2H6O
CH3CH2OH
CH3OCH3
These are called isomers

5. Classification of Organic Compounds
1. Is based on the carbon skeleton
-- all single C-C bonds saturated
-- at least one double or triple C-C bonds unsaturated
2. Is based on the other atoms present
-- if only H and C hydrocarbons
Families of Organic Compounds
Saturated hydrocarbons:
are called alkanes

6. The Alkane Series H CH4 methane|
H—C—H
CH4
methane
See Table P for the first 10 prefixes used in naming organic compounds
H H
| |
H—C—C—H
C2H6
ethane
H H H
| | |
H—C—C—C—H
C3H8
propane
| | | |
—C—C—C—C—
| | | |
C4H10
butane

7. Alkanes have the general formula CnH2n+2 (Table Q)
| | | | |
—C—C—C—C—C—
| | | | |
C5H12
pentane
| | | | | |
—C—C—C—C—C—C—
| | | | | |
C6H14
hexane
| | | | | | |
—C—C—C—C—C—C—C—
| | | | | | |
heptane
C7H16
| | | | | | | |
—C—C—C—C—C—C—C—C—
octane
C8H18
C9H20
nonane
C10H22
decane
Alkanes have the general formula
CnH2n+2
(Table Q)

8. As the alkanes get larger, the melting pt and boiling pt increase
Example:
No. of carbons
gas
liquid
oil
wax
Alkanes with more than 3 carbons have isomers |
—C—
| | |
—C—C—C—
| | | |
—C—C—C—C—
Butane
n-butane
isobutane |
—C—
| | |
—C—C—C—
— C— |
—C—
| | | |
—C—C—C—C—
| | | | |
—C—C—C—C—C—
| | | | |
Pentane
n-pentane
isopentane
neopentane

9. Standard Nomenclature for Alkanes IUPAC System
1. Names are based on the longest chain of carbons |
— C—
| | | | | |
—C—C—C—C—C—C—
—C— |
— C—
| | | | | |
—C—C—C—C—C—C— |
— C—
| | | | | |
—C—C—C—C—C—C— |
— C—
| | | | | |
—C—C—C—C—C—C—
| | | | | |
—C—
6 = hexane
7 = heptane
2. Name the carbon branches (end in –yl)
methylhexane
dimethylheptane

10. 3. Tell location of branches
-- assign numbers to carbon atoms in the chain
-- branch is on the lowest numbered carbon C |
C—C—C—C—C—C C |
C—C—C—C—C—C 5 6 7 
3-methylhexane
3,5-dimethylheptane

11. Halides or Halocarbons
--where a hydrogen has been replaced by a halogen (F, Cl, Br, I)
--same naming rules, branches = fluoro-, chloro-, bromo-, iodo- |
—C—
| | | | | |
—C—C—C—C—C—C— I Br
| | | | |
—C—C—C—C—C—
2-bromopentane
2-methyl-4-iodohexane Br
| | |
Cl —C—C—C—Br Cl
1,3-dibromo-1,2-dichloropropane

12. Alkenes Hydrocarbons with one double bond are called
H H H
| | /
H—C—CC
| \
H H
named like alkanes, but end in - ene
C3H6 = Propene
General formula for the alkenes = CnH2n (Table Q)
Alkenes with 4 or more carbons have isomers even when unbranched
Example : Butene C4H8
H H H H
\ | | |
CC—C—C—H
/ | |
H H H
H H H
| | |
H—C—CC—C—H
| | |
H H H
To Name: number the carbon atoms as before, so the double bond
starts on the lowest numbered carbon

13. Begin the name with the lowest numbered carbon in the double bond
C  C—C—C
C—C  C—C
Begin the name with the lowest numbered carbon in the double bond
1-butene
2-butene
Use the same numbering system for branches
Examples:
| | | | | |
—C—C—C—CC—C—C—
| | | | | |
—C— |
| | | | /
Cl—C—C—C—CC
| | | \
5-chloro-1-pentene
5-methyl-3-heptene

14. Alkynes Hydrocarbons with one triple bond are called
named like alkanes, but end in - yne
H H
| |
H—C—C≡C—C—H
2-butyne = C4H6
General formula for the alkynes = CnH2n (Table Q)
Example:
| | | |
—C—C—C—C≡C—C—
—C— |
4-methyl-2-hexyne
One old name is still widely used:
C2H2 = ethyne = acetylene
—C≡C—

15. Other Organic Families
--consist of a hydrocarbon in which a H has been replaced by a
functional group (Table R)
--the functional group determines the compound’s properties
and reactions
1. Alcohols
functional group: —O—H
[not bases: the –OH does not ionize to form OH-]
named according to the parent hydrocarbon, but...
the –e ending is changed to –ol
a number tells where the –OH is, if necessary
Examples: OH
| | | | |
—C—C—C—C—C—
| |
—C—C—O—H
ethanol
2-pentanol

16. 2. Organic Acids functional group:║
R—C—OH
2. Organic Acids
functional group:
or R-COOH
(R stands for any number of carbons, or just an H)
Examples: O ║
H—C—OH O
| ║
—C—C—OH |
name by parent hydrocarbon ……
drop –e, add -oic acid
IUPAC:
methanoic acid
ethanoic acid
old:
formic aid
acetic acid
Fatty acids have many-carbon R groups: O
| | | | | | | | | | | | | | | | | ║
—C—C—C—C—C—C—C—C—C—C—C—C—C—C—C—C—C—C—OH
| | | | | | | | | | | | | | | | |
saturated O
| | | | | | | | | ║
—C—CC—CC—CC—CC—CC—CC—CC—CC—C—OH
| | | | | | | | |
unsaturated

17. 3. Aldehydes 4. Ketones functional group:║
R—C—H
3. Aldehydes
functional group:
naming: drop -e ending, add -al
Example: O ║
H—C—H
IUPAC: methanal
old: formaldehyde O ║
R1—C—R2
4. Ketones
functional group:
needs at least 3 carbons --
otherwise it’s an aldehyde
naming: drop –e ending, add -one O ║
CH3—C—CH3
Example:
IUPAC: propanone
old: acetone
use numbers to indicate position of O, if necessary

18. 5. Ethers 6. Esters functional group: R1—O—R2
Name both R groups as branches, then “ether”
Example:
CH3—CH2—O—CH2—CH3
diethyl ether O ║
R1—C—O—R2
6. Esters
functional group:
Name is based on the original acid
-- ending is -oate
-- extra carbons are named as a branch O
| ║ | | | | |
—C—C—O—C—C—C—C—C—
| | | | | |
Example:
pentyl ethanoate
many esters have pleasant fragrances

19. Nitrogen-containing families
7. Amines
functional group
R1—N—R3 | R2
(often R2 and R3 are H’s
making –NH2)
name longest carbon chain; drop –e, add -amine
| | | /
—C—C—C—N
| | | \
Example:
1-propanamine
8. Amides
O R2
║ |
R1—C—N—H
functional group
(R2 often = H)
name: drop –e, add -amide
Example:
O H
| | | ║ |
—C—C—C—C—N—H
| | |
butanamide

20. 9. Amino Acids (NOT on Table R but need to know)
have the amine and acid groups O
\ | ║
N—C—C—O—H
/ | R
Different R groups create 20 different amino acids
Amino acids join together in long chains to form proteins

21. Reactions of Organic Compounds
are usually slow
1. Substitution
-- replacing the H of an alkane with a halogen
Example:
H H H
| | |
H—C—C—C—Cl
H H H
| | |
H—C—C—C—H
+ Cl2 
+ HCl
C3H8
C3H7Cl
Result: a mixture of isomers – the Cl can replace any H

22. 2. Addition Example: + Cl2 
-- adding 2 halogen atoms at the site of a multiple bond
Example:
H H H
| | |
H—C—CC—C—H
| | |
H H H
H H Cl H
| | | |
H—C—C—C—C—H
H Cl H H
+ Cl2 
C4H8Cl2
C4H8
Result: one particular isomer
Reactivity: alkynes › alkenes › alkanes
F2 › Cl2 › Br2 › I2

23. When hydrogen is added, the compound becomes saturated.
H H
| |
C C
H H
H H
| |
H—C—C—H H2 + 
This is called hydrogenation
3. Fermentation
Changes sugar  alcohol
C6H12O6  2 C2H5OH CO2
glucose  ethanol carbon dioxide
uses enzymes, from yeast, as catalysts

24. 4. Esterification alcohol + acid  water + ester  HOH║
R—O—C—R— O ║
OH—C—R—
 HOH +
R—OH +
since water is removed, this is an example of a condensation,
or dehydration, reaction
Fats are esters of glycerol and fatty acids
glycerol fatty acids  fat water O ║
—C—O—C—C—C—etc
| O
| ║ O ║
OH—C—C—C—etc |
—C—OH O ║
OH—C—C—C—etc
+ 3 HOH O ║
OH—C—C—C—etc

25. 5. Saponification The breakdown, or hydrolysis, of an ester
ester base  alcohol + salt of organic acid
(soap) O ║
NaO—C—C—C—etc O ║
—C—O—C—C—C—
| O
| ║
Ex. |
—C—OH +
+ NaOH O ║
NaO—C—C—C—etc
+ NaOH O ║
NaO—C—C—C—etc
+ NaOH
fat
+ 3 base 
glycerol +
3 soap

26. 6. Combustion a. if O2 is abundant: complete combustion
hydrocarbon + oxygen  carbon dioxide + water
Ex. CH O  CO H2O
b. if O2 is scarce, or at lower temps:
incomplete combustion
Ex. 2CH O2  CO H2O
Ex. CH O  C H2O

27. 7. Polymerization
the joining together of many small molecules (monomer)
to form a large, chain-like molecule (polymer)
Examples:
chain of sugar molecules =
chain of amino acids = protein
starch, or cellulose
rubber, plastics, natural and synthetic fibers
cotton, wool
nylon, polyester

28. [ ] 2 types of polymerization: A. Condensation polymerization
--produces water as a product
Example:
H H O
| | ║
H—N—C—C—OH | R
H H O
| | ║
H—N—C—C—OH | R
H H O
| | ║
H—N—C—C—OH | R
amino acids
HOH
HOH [ ]
H H O H H O H H O
| | ║ | | ║ | | ║
H—N—C—C—N—C—C—N—C—C—OH
| | |
R R R
H H O
| | ║
—N—C—C— | R OR n
protein

29. [ ] B. Addition Polymerization -- monomer must be unsaturated Example:
H H
| |
CC
H Cl
H H
| |
CC
H Cl
H H
| |
CC
H Cl
chloroethene
(vinyl chloride) [ ]
| | | | | |
—C—C—C—C—C—C—
Cl Cl Cl
| |
—C—C— Cl
polychloroethene
(polyvinyl chloride) or n