1. Isomers For each of the following: 1 Name the compounds shown.
2 Identify the structural isomers.
3 Identify the geometric isomers.

2. butane
propene
methylpropane
ethene
but-1-ene
methylpropene
cis but-2-ene
trans but-2-ene

3. IUPAC name = Alkanols CnH2n+1OH for saturated acohols
Can be written R-OH
Alcohols with three or more carbons form structural isomers.

4. Alcohols

5. Alcohols

6. Naming and Structure -ol replaces the –e Parent chain contains –OH
Position of hydroxyl group determines numbering of alkyl groups (i.e count from the lowest carbon chain)
Prefix –di, -tri indicate multiple functional groups

7. H H H H
H – C – C – C – C – OH
H CH3 H H Butane
H H H H
H – C – C – C – C – OH
H CH3 H H Butan-1-ol
H H H H
H – C – C – C – C – OH
H CH3 H H 3-methylbutane-1-ol

8. Properties Hydrogen bonding due to –OH groups creating polarity
Determines physical properties for smaller molecules
Permanent dipoles and instantaneous dipoles
Non-polar hydrocarbon portion determines properties for larger molecules

9. Melting & Boiling Points
pH & Conduction
Non-conductors
Neutral solutions
Melting & Boiling Points
Higher than corresponding alkane due to hydrogen bonding
Liquids at room temp up to 8Carbons

10. Solubility Up to 3 Carbon soluble in very water
4 Carbon soluble in water
5-6 Carbon slightly soluble
Solubility due to polarity
>6 C insoluble in water due to large non-polar alkyl (hydrocarbon) region.
Commercial solvent as they can dissolve both polar and non-polar substances.

11. 1,2-Ethanediol Two hydroxyl groups = greater hydrogen bonding
Antifreeze
Antiboil
De-icing fluid

12. Alcohols II
Isomerism

13. Cis-trans isomers
Which of the following compounds will have cis-trans isomers?
(Hint: Draw the structure.)
1 CHCl=CH2
2 CH3CH=CHCH2CH3
3 CHCl=CHCl
4 CH2=CBr2
5 CHBr=CBrCH3
The following have cis-trans isomers
2 CH3CH=CHCH2CH3
CHCl=CHCl
5 CHBr=CBrCH3

14. Structural Isomerism H H H H – C – C – C – OH
H CH3 H methylpropan-1-ol
H H H H
H – C – C – C – C – OH
H H H H butan-1-ol

15. Primary, secondary, tertiary
Determined by number of alkyl groups attached to the same carbon as -OH
Distinguished by Lucas reagent (ZnCl2 in conc HCl)
no visible reaction: primary alcohol
solution turns cloudy in 3-5 minutes: secondary alcohol
solution turns cloudy immediately, and/or phases separate: tertiary or benzyl alcohol

16. Primary alcohols
are those alcohols in which the carbon atom to which the hydroxyl group ( OH) is attached has only one carbon attached to it. (usually at the end of the chain)
I.e. the carbon with OH group is bonded to only one other carbon atom.
E.g.

17. Secondary alcohols
are those alcohols in which the carbon atom to which the hydroxyl group ( OH) is attached has two carbons attached to it
E.g. Butan-2-ol

18. Tertiary alcohols

19. Tertiary alcohols
are those alcohols in which the carbon atom to which the hydroxyl group ( OH) is attached has three carbons attached to it

20. Optical Isomers A form of stereoisomerism
In stereoisomerism, the atoms making up the isomers are joined up in the same order, but still manage to have a different spatial arrangement.
Why optical isomers?
Optical isomers are named like this because of their effect on plane polarised light.
Simple substances which show optical isomerism exist as two isomers known as enantiomers.

21. Butan-2-ol