Naphthalene vs. p-Dichlorobenzene

What's the Difference?

Naphthalene and p-Dichlorobenzene are both organic compounds commonly used as moth repellents. However, they differ in their chemical structures and properties. Naphthalene is a white solid with a distinct odor, while p-Dichlorobenzene is a colorless liquid with a strong, sweet smell. Naphthalene consists of two fused benzene rings, making it a polycyclic aromatic hydrocarbon, whereas p-Dichlorobenzene is a chlorinated derivative of benzene. Naphthalene has a higher melting point and vapor pressure compared to p-Dichlorobenzene. Additionally, p-Dichlorobenzene is more toxic and poses a greater risk to human health and the environment.


Chemical FormulaC10H8C6H4Cl2
Molecular Weight128.17 g/mol147.01 g/mol
AppearanceWhite crystalline solidColorless solid
OdorDistinctive mothball-like odorChlorine-like odor
Solubility in WaterInsoluble0.015 g/100 mL
Boiling Point218 °C174 °C
Melting Point80.2 °C53.5 °C
UsesUsed in mothballs, as a solvent, and in the production of dyesUsed as a pesticide, deodorizer, and in the production of chemicals

Further Detail


Naphthalene and p-Dichlorobenzene are two commonly used chemicals with distinct properties and applications. In this article, we will explore and compare the attributes of these compounds, including their chemical structures, physical properties, uses, and potential health and environmental impacts.

Chemical Structures

Naphthalene, also known as mothballs, is a white crystalline solid with a strong, distinctive odor. It consists of two fused benzene rings, resulting in a structure that resembles a pair of fused hexagons. On the other hand, p-Dichlorobenzene, commonly referred to as paradichlorobenzene or PDCB, is a colorless solid with a sweet, aromatic odor. Its chemical structure consists of a benzene ring with two chlorine atoms attached to adjacent carbon atoms.

Physical Properties

When it comes to physical properties, naphthalene has a melting point of around 80°C and a boiling point of approximately 218°C. It is insoluble in water but soluble in organic solvents such as ethanol and acetone. On the other hand, p-Dichlorobenzene has a higher melting point of about 53°C and a boiling point of around 174°C. It is also insoluble in water but soluble in organic solvents.


Naphthalene is primarily used as a moth repellent due to its strong odor, which repels insects. It is also utilized in the production of dyes, resins, and plastics. Additionally, naphthalene is employed as a precursor in the synthesis of various chemicals, including phthalic anhydride and naphthols. On the other hand, p-Dichlorobenzene is commonly used as a deodorizer and insecticide. It is often found in products such as toilet bowl cleaners, air fresheners, and mothballs. Furthermore, p-Dichlorobenzene is utilized as a solvent in the manufacturing of various chemicals and as a fumigant for stored grains.

Health and Environmental Impacts

While both naphthalene and p-Dichlorobenzene have practical applications, it is important to consider their potential health and environmental impacts. Naphthalene, when inhaled or ingested in large amounts, can cause harmful effects on the blood, liver, and kidneys. Prolonged exposure to naphthalene may also lead to the development of cataracts. On the other hand, p-Dichlorobenzene is classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC). It has been associated with liver and lung damage in animals and may have adverse effects on the central nervous system.

From an environmental perspective, naphthalene is considered toxic to aquatic life and can persist in the environment for a long time. It can also contribute to air pollution when released into the atmosphere. On the other hand, p-Dichlorobenzene is moderately toxic to aquatic organisms and can bioaccumulate in the food chain. It is also known to contaminate soil and groundwater, posing a risk to ecosystems.


In conclusion, naphthalene and p-Dichlorobenzene are distinct compounds with different chemical structures, physical properties, and uses. While naphthalene is primarily used as a moth repellent and in the production of various chemicals, p-Dichlorobenzene finds its applications as a deodorizer, insecticide, and solvent. However, it is crucial to be aware of the potential health and environmental impacts associated with these compounds. Naphthalene can have adverse effects on human health and contribute to pollution, while p-Dichlorobenzene is classified as a possible carcinogen and can contaminate ecosystems. Understanding these attributes allows for informed decision-making regarding their usage and potential alternatives.

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