1. Organic chemistry

2. Organic Chemistry Organic means living
Hydrocarbons contain hydrogen and carbon atoms
Organic Chemistry is the study of carbon chemicals that are natural and artificial.
The bonding in hydrocarbons is covalent so bonding between molecules is weak.
The structure is molecular.

3. CH4 (GAS), C8H18 (LIQUID), C30H62 (SOLID)
Homologous series
This is a series of compounds which all contain the same functional group, and have similar chemical properties. 
ALKANES ALKENES ALCOHOLS
CH4 CH2 =CH2 CH3OH
CH3-CH3 CH2 =CH –CH3 CH3CH2OH
Each has a general formula:
ALKANES: CnH2n+2
The members of the series differ by the number of CH2 units.
CH3-CH3, CH3-CH2-CH3, CH3-CH2-CH2-CH3
Graduation in physical properties:  eg: boiling points.
CH4 (GAS), C8H18 (LIQUID), C30H62 (SOLID)

4. IUPAC The International Union of Pure and Applied Chemistry Why?
Historical names (e.g. acetic acid, formic acid) meant nothing to other scientists in different countries

5. IUPAC Rules for Alkane Nomenclature
 1.   Find and name the longest continuous carbon chain. AKA parent chain
 2.   Identify and name groups attached to this chain.  3.   Number the chain consecutively, starting at the end nearest a substituent group.   4.   Designate the location of each substituent group by an appropriate number and name.  5.   Assemble the name, listing groups in alphabetical order.      The prefixes di, tri, tetra etc., used to designate several groups of the same kind, are not considered when alphabetizing.

6. Naming Alkanes General formula CnH2n+2
Saturated compounds: each carbon is bonded to the maximum possible number of atoms.

7. “Prefix + Root + Suffix”
Find the main chain (1 = meth, 2 = eth, 3 = prop, 4 = but, 5 = pent, 6=hex)
Determine your suffix (Alkane = ane)
Number the main chain. Start at the end that gives branches the lowest numbers.
Name each branch as an alkyl group (methyl, ethyl, propyl etc.), and placing a position number in front.
Note: always put commas between numbers, and hyphens between numbers and letters.

8. GENERAL FORMULA CnH(2n+2)
ALKANES
SATURATED HYDROCARBONS – contain maximum amount of hydrogen - only single bonds (no multiple bonds)
NAMING ALKANES
No of C atoms
Prefix 1
Meth 2
Eth 3
Prop 4
But 5
Pent 6
Hex 7
Hept 8
Oct
All alkanes end with ‘ANE’.
All belong to the same HOMOLOGOUS series
GENERAL FORMULA CnH(2n+2)

9. Examples: C H
Methane CH4 C H
Ethane C2H6

10. Alkyl Groups Branches on carbon chains H H C CH3 methyl H
H H H C C CH2CH3 ethyl H H
Hrw z5e 1077
An alkyl group is composed of one or more carbon atoms attached to a carbon chain. An alkyl group is derived from an alkane by removing one hydrogen. The ending –ane of the alkane is changed to –yl. The carbon branch from methane is the methyl group. The carbon branch from ethane is the ethyl group.

11. Name these molecules
3-ethyl-3,4-dimethylhexane

12. STRUCTURES OF ALKANES METHANE CH4 Bond Angle 109.5o Shape Tetrahedral
H C H
Can be illustrated as:

13. ETHANE. Molecular formula C2H6 Structural formula: CH3 CH3 or H H
H C C H
H H

14. PROPANE. Molecular formula: C3H8
Structural formula: CH3 CH2 CH3 or H H H
H C C C H
H H H
Both ethane and propane are “straight” chain molecules
BUT!! Bonds are NOT 90o molecules are NOT STRAIGHT!!!
Schematic formula

15. Give the names of the following alkanes
CH3 CH2 CH CH2 CH3
CH3
(b) CH3 CH CH2 CH CH3
CH CH3
(c) CH3 C(CH3)2 CH2 CH(CH3) CH2 CH3
(d) CH3CH2CH(CH3)C(CH3)3

16. Give the names of the following alkanes
CH3 CH2 CH CH2 CH3
CH3
(b) CH3 CH CH2 CH CH3
CH CH3
(c) CH3 C(CH3)2 CH2 CH(CH3) CH2 CH3
(d) CH3CH2CH(CH3)C(CH3)3
3-methyl pentane
2,4-dimethylpentane
2,2,4-trimethyl
hexane
2,2,3-trimethylpentane

17. Cyclic Alkanes
When C atoms bond together to form a ‘ring’ – known as a ‘cyclic’ structure.
Example
What is the molecular formula of this alkane?
How does the molecular formula compare to the general formula for alkanes?
Why does it belong to the series of alkanes?
Can you think of a name for this molecule
Illustrate the cyclic structures of (a) C4H8 and (b) C5H10 and name the molecules.
CYCLOHEXANE

18. Commas and dashes Use commas between numbers
Use dashes between numbers and letters
And one other thing; when arranging your substituent groups in alphabetical order the di, tri, tetra, etc do not count

19. Correct the mistakes
You have 1 minute to discuss with a partner all the mistakes in the naming of the following compounds

20. 4-methyl-3-4-dichloro-3-bromo-pentane Name B: Cl Cl
H3C C C
CH2
CH3
CH3 Br
Name A:
4-methyl-3-4-dichloro-3-bromo-pentane
Name B:
3-bromo-3,4-dichloro-4-methyl-pentane

21. 4-methyl-3-4-dichloro-3-bromo-pentane Not alphabetical Name B:
3-bromo-2,3-dichloro-2-methylpentane
Key
Incorrect number
Dash or comma Cl Cl 1 4 2 3
H3C C C
CH2 5
CH3
CH3 Br
Name A:
4-methyl-3-4-dichloro-3-bromo-pentane
Not alphabetical
Name B:
3-bromo-3,4-dichloro-4-methyl-pentane

22. Worked example 1 1. 6 carbons in the longest chain  hexane
 2.   has 2 chloro- groups  dichloro
Has a methane group  methyl
 3.   Number the chain (see diagram)   4.   1,2-dichloro-
4-methyl  5.   1,2-dichloro-4-methylhexane
Remember: when arranging your substituent groups in alphabetical order the di, tri, tetra, etc do not count 1 6 2 3 2 4 1 3 5

23. Isomers Same molecular formula Same number and types of atoms
Different arrangement of atoms
Hwr 631; z5e 983 Structural isomers are compounds that have the same molecular formula with different arrangements of the atoms.

24. Examples of Isomers CH3 The formula C4H10 has two different structures
CH3CH2CH2CH3 CH3CHCH3
Butane methylpropane
When a CH3 is is used to form a branch, it makes a new isomer of C4H10.
Hwr z5e 984

25. Structural Isomers pp
Compounds that have the same molecular formula, but different molecular structures, are called structural isomers
Butane and 2-methylpropane on previous slide.
Also have different properties, such as b.p., m.p., and reactivity
Hrw 631; z5e 1068

26. Geometric Isomers pp
There is a lack of rotation around a carbon to carbon multiple bond
has an important structural implication
Two possible methyl arrangements:
1. trans configuration - substituted groups on opposite sides of double bond
2. cis configuration - same side
Hrw 632; z5e 1060

27. Geometric Isomers pp
Differ only in the geometry of their substituted groups
Like other structural isomers, have different physical and chemical properties
Hrw 632; z5e 1059

28. Geometric Isomers of 1,2-dichloroethene
Cl Cl H Cl C=C C=C H H Cl H cis trans
Rigid structure so these are isomers with different properties.
Hrw 632; z5e 1059

29. Geometric Isomers of chloroethene? pp
H Cl H H C=C C=C H H H Cl
Rigid structure BUT both carbons do NOT have two DIFFERENT groups attached to them.
These are just rotated in space, but are the same.
Hrw 632; z5e 1059

30. Nongeometric versions of 1,2-dichloroeth”ene” pp
Cl Cl H Cl C--C C--C H H Cl H
Non-rigid structure so these are NOT isomers. (The 3rd hydrogen on each carbon is not shown)
Hrw 632; z5e 1059

31. BUTANE & ISOMERS.
Molecular formula: C4H can have two different structures
“Straight” chain. CH3 CH2 CH2 CH3
BUTANE
Schematic formula:
Branched chain CH3 CH CH3
CH3
METHYL PROPANE
branch
Isomers
Compounds that have the same molecular formula but different structural formula.

32. TASK:
Illustrate the structures of the three different isomers of C5H12.

33. Names & Structures Examples CH3 CH3 CH CH2 CH3 2- methylbutane CH3
CH3 C CH3
2,2 – dimethyl propane
TASK: illustrate the structures of:
2-methylpentane.
2,3 – dimethylbutane.
2,2,3 -trimethylpentane
CH3CH(CH3)CH2CH2CH3
CH3CH(CH3)CH(CH3)CH3
CH3C(CH3)2CH(CH3)CH2CH3

34. Alkenes CnH2n Ethene C2H4 A by-product of CRACKING an Alkane
Used for making polymers
C=C is more reactive than C-C
The molecule is unsaturated and the double bonds allow addition polymerisation. C H
Ethene C2H4

35. Structure of Alkenes The shape around the double bond is planar.
The bond angle around the double bond is 120o
C C
 bond 
PLANAR
120o
Represented as C C

36. Examples of Alkenes H H C C ………………, C2H4 H H OR …………………….
PROPENE CH2 CH CH3
TASK: Use ball & stick models or sketches to construct and name 3 different structures for C4H8 each one with one double bond.

37. Examples of Alkenes H H C C H H ETHENE, C2H4 OR CH2 CH2 H H C C H CH3
PROPENE CH2 CH CH3
TASK: Use ball & stick models or sketches to construct and name 3 different structures for C4H8 each one with one double bond.
CH3CH2CH CH2
BUT-1-ENE
CH3C CH2
CH3
METHYL PROPENE
CH3CH CHCH3
BUT-2-ENE

38. More Alkenes Illustrate structures of the following alkenes:
Pent-1-ene
Hex-3-ene
2-methylbut-1-ene
Cyclohexene
Name the following alkenes
CH3CH CHCH2CH3
CH2 CHCH(CH3)CH2CH3
CH3CH(CH3)CH CHCH2CH3
(CH3)3CCH C(CH3)2

39. More Alkenes Illustrate structures of the following alkenes:
Pent-1-ene
CH CHCH2CH2CH3
Hex-3-ene
CH3CH2CH CHCH2CH3
2-methylbut-1-ene
CH2 C(CH3)CH2CH3
Cyclohexene
Name the following alkenes
CH3CH CHCH2CH3
Pent-2-ene
3-methylpent-1-ene
CH2 CHCH(CH3)CH2CH3
2-methylhex-3-ene
CH3CH(CH3)CH CHCH2CH3
(CH3)3CCH C(CH3)2
2,4,4-trimethylpent-2-ene

40. GEOMETRIC ISOMERS There is no rotation about the double bond.
GEOMETRIC ISOMERISM each C atom in the double bond has two different atoms/groups attached.
BUT–2-ENE CH3 CH CH CH3
CH H
C C
H CH3
CH CH3
C C
H H
trans but-2-ene
cis but-2-ene
Geometric isomerism is a form of STEREOISOMERISM –
Same molecular and structural formula but atoms are arranged differently in space

41. Alkynes H-C≡C-H Ethyne Very reactive Triple bond unstable!
Attracts electrophiles.
H-C≡C-CH3
propyne
H-C≡C-CH2-CH3
But–1-yne
CH3-C≡C-CH3
But–2-yne