The key difference between malathion and parathion is that malathion is less toxic and comparatively has the lowest effects, whereas parathion is the most toxic insecticide and has the strongest effects.
Malathion and parathion are two types of insecticides that are useful for agricultural purposes. They are toxic substances and can harm or affect the biological cycles in nature. Although malathion is still widely used for agricultural purposes, parathion is not in use in many countries because its use has been banned due to its toxic effects.
CONTENTS
1. Overview and Key Difference
2. What is Malathion
3. What is Parathion
4. Malathion and Parathion in Tabular Form
5. Summary – Malathion vs Parathion
What is Malathion?
Malathion is an organophosphate insecticide that can act as an acetylcholinesterase inhibitor. It is used widely as a pesticide in agriculture, residential landscaping, public recreation areas, and public health pest control programs, including mosquito eradication. This is the most common insecticide in the US. The chemical formula of malathion is C10H19O6PS2. Its molar mass is 330.35 g/mol. It is a clear, colorless liquid that has a density of 1.23 g/cm3. The melting point is 2.9 degrees Celsius, and the boiling point can range from 156 to 157 degrees Celsius. This substance is soluble in ethanol and acetone as well as in ethyl ether.
Figure 01: The Chemical Structure of Malathion Molecule
The method of production of malathion can be given as the addition of dimethyl dithiophospheric acid to diethyl maleate or diethyl fumarate. This compound is chiral, and it is useful as a racemate. When considering the mechanism of action of malathion, it is taken up into the target organism and binds irreversibly to the serine residue in the active catalytic site of the cholinesterase enzyme. This gives a phosphoester group that is strongly bound to the cholinesterase. This can irreversibly deactivate the enzyme leading to the rapid build-up of acetylcholine at the synapse.
What is Parathion?
Parathion is an organophosphate insecticide and an acaricide. It is also named parathion-ethyl or diethyl parathion, and its local name is Folidol. This substance was originally developed by IG Farben in the 1940s. Parathion is highly toxic to humans and other non-target organisms. Therefore, the use of this substance was banned in many countries.
Figure 02: The Chemical Structure of Parathion Molecule
The chemical formula of parathion is C10H14NO5PS, and the molar mass is 291.26 g/mol. Parathion appears as white crystals in its pure form. The melting point of parathion is 6 degrees Celsius. The solubility in water is poor, and it shows high solubility in xylene and butanol. Commonly, this substance is distributed as a liquid having the smell of rotting eggs or garlic. This insecticide is somewhat stable, but it darkens upon exposure to sunlight.
When considering the production mechanism, it is industrially produced from diethyl dithiophosphoric acid via chlorination in generating diethylthiophosphoryl chloride. Thereafter, the chloride product is treated with the sodium salt of 4-nitrophenol.
What is the Difference Between Malathion and Parathion?
Malathion and parathion are toxic insecticides. We can categorize them according to their toxicity. The key difference between malathion and parathion is that malathion is less toxic and has the lowest effects comparatively, whereas parathion is the most toxic insecticide and has the strongest effects. Moreover, malathion is still in use as an insecticide, while parathion is not in use as it is banned in many countries.
The below infographic presents the differences between malathion and parathion in tabular form for side by side comparison.
Summary – Malathion vs Parathion
The key difference between malathion and parathion is their toxicity. Malathion is less toxic and comparatively has the lowest effects, whereas parathion is the most toxic insecticide and has the strongest effects.
Reference:
1. “Malathion.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Malathion” By Benjah-bmm27 – Own work (Public Domain) via Commons Wikimedia
2. “Methyl & Ethylparathion” By Smokefoot – Own work (Public Domain) via Commons Wikimedia