1. Organic Chemistry
Chapter 22

2. Vocabulary Organic Chemistry Carbonyl group Hydrocarbons Ketones
Saturated
Unsaturated
Alkanes
Alkenes
Alkynes
Cis-trans isomerism
Carbonyl group
Ketones
Aldehydes
Carboxylic acids
Carboxyl group
Ester
Ether
Amine

3. Saturated vs. Unsaturated Hydrocarbons
Hydrocarbons are molecules composed of carbon & hydrogen
Each carbon atom forms 4 chemical bonds
A saturated hydrocarbon is one where all C - C bonds are “single” bonds & the molecule contains the maximum number of H-atoms
An unsaturated hydrocarbon is one where at least 1 C=C bond is double.

4. Prefixes for # of Carbons1
Meth 6
Hex 2
Eth 7
Hept 3
Prop 8
Oct 4
But 9
Non 5
Pent 10
Dec

5. Alkanes Formula: (CnH2n+2)
Hydrocarbon chains where all the bonds between carbons are SINGLE bonds
Name uses the ending –ane
Examples: Methane, Propane, Butane, Octane
Formula: (CnH2n+2)

6. Straight-Chain Alkanes
Straight-chain alkanes contain any number of carbon atoms, one after the other, in a chain pattern - meaning one linked to the next (not always straight)
C-C-C C-C-C-C etc.

7. Writing/drawing compounds
Line formula

8. Normal vs Branched Alkanes
NORMAL alkanes consist of continuous chains of carbon atoms
Alkanes that are NOT continuous chains of carbon atoms contain branches
The longest continuous chain of carbons is called the parent chain

9. Endings Attached carbon groups (substituents) end in –yl Methyl CH3 -
Ethyl CH3CH2-
Propyl CH3CH2CH2 –     
3-ethylpentane

10. Names of branches Carbon (alkyl) groups Methyl CH3 - Ethyl CH3CH2-
Propyl CH3CH2CH2 –

11. Branched-Chain Alkanes
Rules for naming –
1. Longest C-C chain is parent
2. Number so branches have lowest #
3. Give position number to branch
4. Prefix (di, tri) more than one branch
5. Alphabetize branches (not prefix)
6. Use proper punctuation ( - and , )

12. Designate the Location
Designate the location (number of the carbon on the parent chain) for each attached group
2-methyl

13. Name this compound
3,3-dimethylhexane

14. Some Simple Alkanes 2-methylpentane 3-ethylhexane 2,2-dimethylbutane

15. Branched-Chain Alkanes
From the name, draw the structure, in a right-to-left manner:
1. Find the parent, with the -ane
2. Number carbons on parent
3. Identify substituent groups (give lowest number); attach
4. Add remaining hydrogens

16. Example 1: 2,2-dimethylpentane
The parent chain is indicated by the ROOT of the name - “pentane”. This means there are 5 carbons in the parent chain. 1 2 3 4 5
“dimethyl” tells us that there are TWO methyl branches on the parent chain. A methyl branch is made of a single carbon atom.
“2,2-” tell us that BOTH methyl branches are on the second carbon atom in the parent chain.

17. Example 2: 3-ethyl-2,4-dimethylheptane1 2 3 4 5 7 6
The parent chain is indicated by the ROOT of the name - “heptane”. This means there are 7 carbons in the parent chain.
“2,4-dimethyl” tells us there are TWO methyl branches on the parent chain, at carbons #2 and #4.
“3-ethyl-” tell us there is an ethyl branch (2-carbon branch) on carbon #3 of the parent chain.

18. Example 3: 2,3,3-trimethyl-4-propyloctane
The parent chain is indicated by the ROOT of the name - “octane”. This means there are 8 carbons in the parent chain. 1 2 3 4 5 7 6 8
“2,3,3-trimethyl” tells us there are THREE methyl branches - one on carbon #2 and two on carbon #3.
“4-propyl-” tell us there is a propyl branch (3-carbon branch) on carbon #4 of the parent chain. 1 2 3 4 5 7 6 8

19. Example 4: Name the molecules shown!
parent chain has 5 carbons - “pentane”
two methyl branches - start counting from the right - #2 and #3
2,3-dimethylpentane
parent chain has 8 carbons - “octane”
two methyl branches - start counting from the left - #3 and #4
one ethyl branch - #5
name branches alphabetically 5
5-ethyl-
3,4-dimethyl 4 3
octane

20. Draw 2,2,4-trimethylpentane

21. Structural Isomerism
Structural isomers are molecules with the same chemical formulas but different molecular structures
n-pentane, C5H12
2-methlbutane, C5H12

22. However, carbons in butane (C4H10) can be arranged in two ways; four carbons in a row (linear alkane) or a branching (branched alkane). These two structures are two isomers for butane.

23. Your Turn
Draw all possible structural isomers of C5H12

24. Practice

25. IUPAC Rules for Naming Branched Alkanes
Find and name the parent chain in the hydrocarbon - this forms the root of the hydrocarbon name
Number the carbon atoms in the parent chain starting at the end closest to the branching
Name alkane branches by dropping the “ane” from the names and adding “yl”. A one-carbon branch is called “methyl”, a two-carbon branch is “ethyl”, etc…
When there are more than one type of branch (ethyl and methyl, for example), they are named alphabetically
Finally, use prefixes to indicate multiple branches

26. CLASSWORK ASSIGNMENT Review section 22-1
make notes on NONMENCLATURE OF ALKANES and CYCLIC ALKANES
Pay attention to sample exercises!

27. Alkenes & Alkynes
Alkenes are hydrocarbons that contain at least one carbon-carbon double bond
Alkynes are hydrocarbons that contain at least one carbon-carbon triple bond
The suffix for the parent chains are changed from “ane” to “ene” and “yne”
e.g. ethene, propyne
the BONDS are numbered like branches so that the location of the multiple bond may be indicated

28. Alkenes & Alkynes: Examples
ethene
ethyne
propene
propyne
butene
2-pentyne

29. Aromatic Hydrocarbons Cycloalkanes
A cycloalkane is made of a hydrocarbon chain that has been joined to make a “ring”.
Note that two hydrogen atoms were lost in forming the ring!

30. Aromatic Hydrocarbons Cycloalkanes
The two ends of the carbon chain are attached in a ring in a cyclic hydrocarbon
named as “cyclo- ____”

31. Aromatic Compounds and Benzene
Aromatic compounds contain benzene.
Benzene, C6H6 , is represented as a six carbon ring with 3 double bonds.
Two possible resonance structures can be drawn to show benzene in this form.

32. Aromatic Hydrocarbons
Benzene derivatives can have two or more substituents:
1,2-dimethylbenzene
1,3-dimethylbenzene
1,4-dimethylbenzene
Can use ortho for 1,2; meta for 1,3; and para for 1,4 (page 711) C C C C

33. With organic compounds
Isomers
With organic compounds

34. Isomers
There is a lack of rotation around a carbon to carbon multiple bond
Two possible arrangements:
1. trans configuration - substituted groups on opposite sides of double bond
2. cis configuration - same side

35. Geometric Isomers
Substituted groups are on opposite sides of the double bond (in this case, one is above, the other is below)
Trans-2-butene
Substituted groups are on the same side of the double bond (in this case, both are above)
Cis-2-butene

36. Cis-Trans Isomers - Examples
cis-1,3-dimethylcyclobutane
cis-1,2-dichlorocyclohexane
trans-1-ethyl-2-methylcyclopropane

37. With organic compounds
Reactions
With organic compounds

38. 2C2H6(g) + 7O2(g)  4CO2(g) + 6H2O(g)
Alkanes
1. Combustion reactions
2C2H6(g) + 7O2(g)  4CO2(g) + 6H2O(g)
2. Substitution reactions
CH4 + Cl2  CH3Cl + HCl
Methane chloromethane
3. Dehydrogenation reactions
CH3CH3 CH2=CH2 + H2
Ethane ethene hv
500C

39. CH2 =CHCH2CH2CH3 + Br2  CH2 BrCHBrCH2CH2CH3
Alkenes & Alkynes
1. Addition reactions
a. Hydrogenation
CH2 =CHCH3+ H2  CH3CH2CH3
Propene Propane
b. Halogenation
CH2 =CHCH2CH2CH3 + Br2  CH2 BrCHBrCH2CH2CH3
Pentene ,2-dibromopentene
c. Polymerization
Small molecules = large molecules
Catalyst

40. Aromatic
1. Substitution reactions + Cl2  + HCl
Catalyst = FeCl3

41. With organic compounds
Functional Groups
With organic compounds

42. Functional group: an atom or group of atoms within a molecule
Functional Groups
Functional group: an atom or group of atoms within a molecule

43. Functional Groups

44. Alcohols
contain an -OH (hydroxyl) group

45. Halides & Carboxylic Acids
contain an -X (Halogen) group
F, Cl, Br, I, At
contain a carboxyl (-COOH) group

46. Aldehydes and Ketones
contain a carbonyl (C=O) group

47. Amines
contain an amino group; nitrogen bonded to one, two, or three carbon atoms
an amine may by 1°, 2°, or 3° C H 3 N
Methylamine
(a 1° amine)
Dimethylamine
(a 2° amine)
Trimethylamine
(a 3° amine) :

48. Esters & Ethers
Ester: trapped carboxylic acid
Ether: Trapped oxygen

49. Branches CnH2n+2 Alkane CnH2n+1 Alkyl group CH4 methane CH3 Methyl
propane
–C3H7
propyl
CH3CHCH3
methylethyl

50. R-O-R’ ether Functional Group General Formula Name Examples
alkanone
butan-2-one
-COOH
RCOOH
alkanoic acid
ethanoic acid
-COOR’
RCOOR’
ester
methyl ethanoate
saturated ring
CnH2n
cycloalkane
cyclohexane -X
-RX
haloalkane
chloroethane
R-O-R’
ether
ethoxyethane
-OH
ROH
alkanol
ethanol
(-CHO)
RCHO
alkanal
ethanal
amine
-NH2
RNH2
methylamine

51. Naming

52. Naming

53. Naming