The key difference between chloroform and dichloromethane is that chloroform contains three chlorine atoms per molecule, whereas dichloromethane contains two chlorine atoms per molecule.
Chloroform and dichloromethane are organochlorine molecules containing similar atomicity and a similar geometry or molecular shape.
CONTENTS
1. Overview and Key Difference
2. What is Chloroform
3. What is Dichloromethane
4. Side by Side Comparison – Chloroform vs Dichloromethane in Tabular Form
5. Summary
What is Chloroform?
Chloroform is an organic compound having the chemical formula CHCl3. It is useful as a powerful anaesthetic. The IUPAC name of this compound is trichloromethane. It is a colourless and dense liquid that has a sweet smell. Chloroform is produced on a large scale as a precursor to producing PTFE. Furthermore, most of the chloroform in the environment (about 90%) is due to emissions of natural origin. For example, many types of seaweed and fungi produce this compound and release it into the atmosphere.
The molar mass of chloroform is 119.37 g/mol, and it appears as a colourless liquid at room temperature. This liquid has a heavy ethereal odour. Its melting point is −63.5 °C, and the boiling point is 61.15 °C. Moreover, chloroform decomposes at 450 °C. This molecule has a tetrahedral geometry.
Figure 01: Chemical Structure of Chloroform
On an industrial scale, we can produce this compound via heating a mixture of chlorine and chloromethane (or sometimes we use methane as well). Upon heating, a free radical halogenation occurs at 400–500 °C. This forms chlorinated compounds of chloromethane (or methane), which yield chloroform. This compound can undergo further chlorination, forming carbon tetrachloride. However, the end product of this reaction is a mixture of chloromethanes we can separate via distillation in order to get chloroform.
There are many uses of chloroform. It is useful as a solvent because the hydrogen atom in this molecule can undergo hydrogen bonding. We can use it as a reagent for many chemical reactions as well. Ex: as a source of dichlorocarbene group. More importantly, chloroform is well-known for its anaesthetic properties.
What is Dichloromethane?
Dichloromethane is an organic compound having the chemical formula CH2Cl2. It is an organochlorine compound, and we can denote it as DCM. This compound occurs as a volatile, colourless liquid consisting of a chloroform-like sweet odour. Dichloromethane is mainly useful as a solvent. This liquid is not miscible with water though it is a polar compound. However, it can mix with many other organic solvents.
Figure 02: Chemical Structure of Dichloromethane
There are some natural sources of dichloromethane, which include oceanic sources, macroalgae, wetlands, and volcanoes. However, we can observe that most of the dichloromethane in the environment is due to industrial emissions. We can produce dichloromethane through the treatment of chloromethane or methane with chlorine gas at high temperatures.
What is the Difference Between Chloroform and Dichloromethane?
Chloroform and dichloromethane are organochlorine molecules. The key difference between chloroform and dichloromethane is that chloroform contains three chlorine atoms per molecule, whereas dichloromethane contains two chlorine atoms per molecule. Moreover, chloroform can be produced by heating a mixture of chlorine and chloromethane, while dichloromethane can be produced through the treatment of chloromethane or methane with chlorine gas at high temperatures.
The below infographic lists the differences between chloroform and dichloromethane in tabular form.
Summary – Chloroform vs Dichloromethane
In brief, chloroform and dichloromethane are organochlorine molecules. The key difference between chloroform and dichloromethane is that chloroform contains three chlorine atoms per molecule, whereas dichloromethane contains two chlorine atoms per molecule.
Reference:
1. “Chloroform.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
Image Courtesy:
1. “Chloroform displayed” By Benjah-bmm27, Vectorization: Fvasconcellos – converted by Fvasconcellos (Public Domain) via Commons Wikimedia
2. “Dichloromethane molecular structure” By Ohnodoctor – Drawn with ChemDraw (CC BY-SA 4.0) via Commons Wikimedia