Phenols are organic compounds featuring a hydroxyl group bonded to an aromatic hydrocarbon, and they are used in industries ranging from pharmaceuticals to cosmetics. Discovered in 1834, phenol has various sources, including natural occurrences in plants and synthetic production from coal tar, and it has distinct physical properties such as high boiling and melting points due to strong hydrogen bonding. However, phenols are toxic and can affect health and the environment, necessitating safety measures during use and disposal.

1. Organic
Chemistry
By: Jericho Y. Salgon

2. PHENOLS

3. PHENOL
S
Introduction to Phenols
* Definition and General Characteristics
* History of Phenols
Sources and Occurrences of Phenols
* Natural Sources
* Industrial Production
Physical and Chemical Properties
* Boiling and Melting Points
* Solubility
Nomenclature of Phenols
* Functional Group and Structure
* Steps of Naming phenols
Application and Uses of Phenols
* Health and Safety

4. INTRODUCTION OF
PHENOLS
Phenols are organic compounds that contain
a hydroxyl group (-OH) directly bonded to an
aromatic hydrocarbon group.
General Formula: ArOH (where Ar represents an
aryl group).
Consists of a hydroxyl group attached to
a benzene ring

5. Phenol is hydroxybenzene. Phenol is common name for the
compound. Its IUPAC name would be benzenol.
Substituted phenols are named as derivatives of the parent
compound phenol. However, phenyl substituted alkyl alcohols are
normal alcohols and often have common names.
INTRODUCTION OF
PHENOLS

7. HISTOR
Y
• Phenol was discovered in 1834 by Friedlieb Ferdinand Runge,
who extracted it (in impure form) from coal tar. Runge called
phenol "Karbolsäure" (coal-oil-acid, carbolic acid In 1841.
• The French chemist Auguste Laurent obtained phenol in pure
form. In 1836, Auguste Laurent coined the name "phène" for
benzene; this is the root of the word "phenol" and "phenyl".
• In 1843, French chemist Charles Gerhardt coined the name
"phénol".
• The antiseptic properties of phenol were used by Sir Joseph
Lister (1827-1912) in his pioneering technique of antiseptic
surgery. The skin irritation caused by continual exposure to
phenol eventually led to the introduction of aseptic (anti-septic,
germ- free) techniques in surgery.

8. SOURCES AND
OCCURRENCES
Natural Sources
Found in essential oils of plants, such as thymol in thyme
and eugenol in cloves
- Present in lignin, a complex polymer in plant cell walls.
- Found in amphibian (phenolic toxins) and microorganism.

9. Synthetic Sources
Phenol can extracted from coal tar. A byproduct of coke
production from coal. Coal tar distillation yields various phenolic
compounds.
- Pharmaceutical (aspirin
acetylsalicylic acid)
- Food and Beverages
- Cosmetics
SOURCES AND
OCCURRENCES

10. PHYSICAL AND CHEMICAL PROPERTIES
All phenols have peculiar smell.
They are colorless compounds but oxygen from the air can cause
brown colour of phenols (oxidation).
• Boiling and Melting Points:
- Phenol (C₆H₅OH): Melting point 40.5°C, boiling point
181.7°C.
Phenols have stronger intermolecular hydrogen bonding than
alcohols, leading to higher boiling and melting points.

12. • Solubility:
- Soluble in water due to hydrogen bonding.
- Solubility decreases with increasing alkyl group size.
- Soluble in organic solvents like ethanol, ether, and chloroform.
• Acidity:
- Phenols are weak acids, pKa around 10.
- Form phenoxide ions (ArO⁻) when they lose a hydrogen ion
(H⁺).

14. NOMENCLATURE OF PHENOLS
General Rules for Naming Phenols
• 1. Identify the hydroxyl group (-OH) as the primary functional
group.
• 2. Number the benzene ring starting from the carbon
bonded to the -OH group.
Phenol 3-methylphenol 3,5-dimethylphenol
2-phenylethanol 3-hydroxy benzoic acid

15. Number the benzene ring starting from the carbon bonded to the -
OH group. Proceed in a way that gives the lowest numbers to the
substituents.
NOMENCLATURE OF PHENOLS
3-methylphenol 2-chlorophenol 2,6-dimethylphenol
2,6-dimethylphenol 2,4,6-trichlorophenol
4-chloro-3,5-dimethylphenol

16. Phenols with only one other substituent can be named using
either the appropriate numbers or the ortho (1,2), meta (1,3),
and para (1,4) system

17. APPLICATION AND USES OF PHENOLS
Industrial Applications
Used in the manufacture of plastics (e.g.,
phenolic resins).
Used as intermediates in the production of
synthetic fibers and adhesives
Pharmaceutical Uses
• - Salicylic acid (a phenol derivative) is
used to make aspirin.
• - Phenol itself is used in throat sprays
and as a disinfectant.
Phenol is also used in cosmetic industry in
the manufacturing of sunscreens, skin
lightening creams and hair coloring
solutions

18. HEALTH AND SAFETY
• Toxicity:
- Phenols are toxic and can cause burns upon contact with skin.
- Inhalation can cause respiratory issues.
• Environmental Impact:
- Phenols can pollute water and soil if not disposed of properly.
- Biodegradation can be slow, leading to accumulation in the
environment.
• Safety Measures:
- Use personal protective equipment (PPE) like gloves and goggles.
- Ensure good ventilation and use fume hoods to avoid inhalation of
vapors.
- Follow proper disposal guidelines to minimize environmental impact.

19. THANK YOU!