1. 1.4 Alcohols

2. ALCOHOL an organic compound that contains a hydroxyl group (-OH)
named using the parent alkane and ending in “ol”
alcohols are POLAR molecules
the C-O bond is polar and so is the O-H bond!

3. THREE CLASSES OF ALCOHOLS:
PRIMARY
SECONDARY
TERTIARY
- OH bonded to terminal C atom
-OH bonded to C atom with 2 alkyl groups attached
-OH is bonded to a C atom with 3 alkyl groups

4. NAMING ALCOHOLS
use the parent alkane, drop -e and add –ol (keep the “e” if it has more than 1 hydroxyl group)
include the carbon number to which -OH attaches (unless it is cyclic…then it is #1 by default)
if there are hydrocarbon or halide substituents, give the lowest number carbon to the hydroxyl (-OH) group preferentially

5. ISOMERS OF ALCOHOLS

6. POLYALCOHOLS
contain more than one -OH group

7. CYCLIC HYDROCARBONS can also form alcohols
use the root name of the cyclic HC and add the suffix -ol

8. AROMATIC HYDROCARBONS
can have -OH groups added, forming an aromatic alcohol
Right example: can be called 1,2-dihydroxybenzene, benzene-1,2-diol, ortho-benzenediol (ortho 1,2; meta 1,3; para 1,4)

9. EXAMPLE 1: Name and identify the type of alcohol.

10. EXAMPLE 2: Draw the structure of butane-1,3-diol

11. PRACTICE TIME!
p. 34 #1 & 2

12. PROPERTIES OF ALCOHOLS
#1) Alcohols have much higher boiling points than the corresponding alkanes
METHANOL
METHANE
BP = 65 C
BP = -162 C
polar molecule
nonpolar molecule
- strong dipole-dipole forces
- H bonding between OH groups of adjacent molecules
- weak VDW forces

13. PROPERTIES OF ALCOHOLS
#2) The shorter the carbon chain, the more soluble the alcohol because the -OH group increases polarity.
But if the HC chain is very long, it causes the entire molecule to become nonpolar.
Usefulness as a solvent???

14. REACTIONS OF ALCOHOLS

15. 1. Preparation of Methanol carbon monoxide + hydrogen gas= methanol
(INDUSTRIAL PROCESS)
breakdown of organic matter by anaerobic bacteria
(natural process)
2. Preparation of Ethanol (fermentation)
sugar from beets, corn, or sugar cane + yeast = ethanol + carbon dioxide (natural process- called fermentation)
ethene + water= ethanol (addition reaction)

16. 3. Combustion of Alcohol (Propanol)
ALL organic matter can undergo complete combustion in the presence of oxygen (products: CO2 + H20 ) or incomplete combustion when oxygen concentration is low (products also include C(s)- soot, and toxic carbon monoxide, CO (g))
4. Hydration (remember Markovnikov’s rule!)
When adding H-X to an alkene, the H goes preferentially to the carbon that already has more H-s.
cis-2-bromobut-2-ene + H20 = 2-bromobutan-2-ol

17. 5. Dehydration of Alcohols from Alkenes + water
removes a hydrogen atom and a hydroxyl group
catalyzed by H2SO4

18. EXAMPLE 1: Write the chemical equation of the addition reaction of pent-1-ene and water

19. EXAMPLE 2: Write the chemical equation of the dehydration of ethanol.

20. HOMEWORK:
practice p. 37 #1&2