This document discusses alcohols and phenols. It defines alcohols as compounds containing a hydroxyl (-OH) group, and describes the IUPAC nomenclature for naming alcohols. Alcohols are classified as primary, secondary, or tertiary based on the number of alkyl groups attached to the carbon bearing the hydroxyl group. Alcohols have higher boiling points than alkanes due to hydrogen bonding. Common reactions of alcohols include reactions with metals, acids, elimination, oxidation, and substitution. Phenols contain a hydroxyl group attached directly to an aromatic phenyl ring, making them more acidic than alcohols.
2. Alcohols
Alcohols are compounds that posses a hydroxyl group (-OH), the name for this kind of group is
characterized by ending in “ol”.
For example:
In the nomenclature of alcohols remember:
The name of the parent replace the suffix “e” by “ol”, example: pentane to pentanol
When choosing the parent, choose the longest chain that includes the carbon with the –OH.
Start the numertion of the parent starting from the end closest to the –OH group
The positions of the hydroxyl group must be indicated, example: 3-pentanol
Source: Klein, David. Organic Chemistry. 3rd Edition.
3. Classification of Alcohols
Alcohols can be designed as primary, secondary or tertiary, depending on the number of alkyl groups
attached directly to the alpha position (this is the carbon atom bearing the –OH group)
Source: Klein, David. Organic Chemistry. 3rd Edition.
4. Physical properties of Alcohols
Alcohols have higher boiling points than alkanes due to the presence of the hydrogen
bonding interactions that can be formed between the molecules of alcohols.
This property makes the interaction of alcohols with water fairly strong.
In this way alcohols have two regions. The hydrophobic region do not interact well
with water (this is the hydrocarbon chain), and the hydrophilic region that does
interact with water through hydrogen bonding (this is the –OH group). As the
hydrophobic region increase the solubility of the alcohols decrease.
Image from:
https://archives.library.illinois.edu/erec
/University%20Archives/1505050/Orga
nic/Alcohols/Chapter%206/sec6-2/6-
2.htm
Source: Klein, David. Organic Chemistry. 3rd Edition.
5. Alcohol reactions
Reaction with active metals: Highly reactive metals like sodium (Na) react with alcohols to produce
the corresponding alkoxide and hydrogen gas.
Example: 2CH3OH + 2Na → 2CH3ONa + H2
Substitution: alcohols react with acids to form halogenated hydrocarbons.
Example: CH3CH2OH + HBr → CH3CH2Br + H2O
Elimination or dehydration: in presence of concentrated acids such as H2SO4, alcohols react and
eliminate water to form alkenes.
Example: CH3CH2OH + H2SO4 → CH2 = CH2 + H2O
6. Alcohol reactions
Oxidation: this process involves the loose of a H bond and the formation of a C=O bond.
Common oxidizing reagent is chromic acid, H2CrO4.
The oxidation process will depend on the starting alcohol. Primary alcohols can by oxidized to
aldehydes and this ones can be oxidizes to carboxylic acid. Secondary alcohols can be oxidized to
ketones. Tertiary alcohols cannot be oxidized.
Source: Klein, David. Organic Chemistry. 3rd Edition.
7. Phenols
Phenols are compounds with an –OH group connected directly to a phenyl
ring.
Phenol is more acidic than alcohols since the conjugate base is stabilized by
resonance.
Source: Klein, David. Organic Chemistry. 3rd Edition.
Editor's Notes
Ketones cannot be oxidized because there is no more hydrogen atoms to get rid off. The same happens with the tertiary alcohols, the carbon atom have no H atoms bonded to it.
