Organic Compounds

- Alcohols -

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Ethanol◦ Adult beverages and Biofuel

Menthol ◦ TigerBalm, Vicks Vaporub◦ Listerine (menthol and ethanol)

Ethylene glycol◦ Car antifreeze

Cholesterol

Common Alcohol Compounds

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Members of the alcohol family contain a hydroxyl (-OH) group making them polar molecules

The –OH is capable of hydrogen bonding (the strongest of intermolecular forces)

Presence of –OH causes an increase in attractive forces between molecules in comparison to hydrocarbon chains of equal size

e.g Ethanol b.p. 78 ºC Ethane b.p. -89 ºC

Alcohol Properties

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Short chained alcohols dissolve completely in water

Longer chained alcohols dissolve well in non-polar solutions because of their long hydrocarbon tails (phospholipids)

Three types of alcohols alcohols are sub-classified according to the

type of carbon to which the –OH group is attached

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An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only one other carbon atom

Primary (1°) Alcohol

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An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only two other carbon atom

Secondary (2°) Alcohol

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An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only three other carbon atom

Tertiary (3°) Alcohol

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1) Locate the longest chain that contains an –OH group attached to one of the carbon atoms. Name the parent alkane.

  NOTE: Cyclic alcohols. An –OH (hydroxyl)

group can be attached to a cyclic hydrocarbon and may be considered attached to the parent chain.

2) Replace the –e at the end of the name of the parent alkane with –ol.

IUPAC Naming of Alcohols

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3) Add a position number before the root of the name to indicate the location of the –OH group. (Remember to number the main chain of the hydrocarbon so that the hydroxyl group has the lowest possible position number.)

NOTE: If there is more than one –OH group, leave the –e in the name of the parent alkane, and put the appropriate preix (di-, tri-, or tetra-) before the suffix –ol)

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4) Name the number of any other branches on the main chain. Add the name of these branches to the prefix.

5) Put the name together: prefix + root + suffix

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Naming Alcohols Practice

OH

OH

OH

OH

HO

OH

OH

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1,3-butadiol

1,2,3-propatriol

2-methyl-2-propanol

2-propanol

Naming Alcohols PracticeOH

OH

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phenol

2,3-dimethylphenol

1) Addition (hydration)

2) Oxidation (combustion)

3) Substitution

4) Elimination (dehydration)

Four Common Reactions Involving Alcohols

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Preparing alcohols from alkenes◦Hydration: addition reaction with water◦An acid is needed as a catalyst (H2SO4(aq))◦Must follow Markovnikov’s Rule

1) Addition (hydration)

General Equation:

Specific Example:

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Alcohols undergo complete combustion to produce carbon dioxide and water

2) Oxidation (combustion)

Specific Example:

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Preparing alkyl halides from alcohols◦ Substitute a halogen for a hydroxyl group

◦ Aqueous acids (HCl, HBr, HF and HI) are needed

Specific Example:

CH3 – CH2 – OH + HCl CH3 – CH2 – Cl + H2O

3) Substitution

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Preparing alkenes from alcohols Results in the removal of water Requires a catalyst (concentrated H2SO4)

NOTE: The opposite reaction would be a hydration

4) Elimination (dehydration)

General Equation:

Specific Example:

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Learning CheckpointAssigned Questions:p.41 #1,2,3 (naming) p.42 #4,5 (properties) p.44 #7,8,9

Worksheet - Reactions and Functional Groups (Alkenes and Alcohols)

Read “Driving your car on ethanol article” and answer questions from the article

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