2-Chlorobenzoyl chloride
[CAS# 609-65-4]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic acid halide
• Name: 2-Chlorobenzoyl chloride
• Synonyms: OCOC; 2-Chlorobenzoic acid chloride
• Molecular Formula: C₇H₄Cl₂O
• Molecular Weight: 175.01
• CAS Registry Number: 609-65-4
• EC Number: 210-194-0
• SMILES: C1=CC=C(C(=C1)C(=O)Cl)Cl

Properties

• Density: 1.382
• Melting point: -4--3 °C
• Boiling point: 238 °C
• Refractive index: 1.5708-1.5728
• Flash point: 110 °C

Safety Data

• Hazard Symbols: GHS05 Danger
• Risk Statements: H314
• Safety Statements: P260-P264-P280-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P321-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Serious eye damage	Eye Dam.	1	H318

Discovery and Applications

2-Chlorobenzoyl chloride is an aromatic acid chloride with a chlorine atom attached to the benzene ring at the ortho position relative to the acyl chloride group. This compound is widely used as a reactive intermediate in organic synthesis due to its highly electrophilic nature, which makes it suitable for the production of pharmaceuticals, agrochemicals, and polymers. Its structure, featuring both a chlorine atom and an acyl chloride group, enhances its reactivity, allowing for versatile chemical transformations.

The discovery of 2-chlorobenzoyl chloride stems from early studies of substituted benzoyl chlorides, which were sought for their utility in acylation reactions. Its ortho-substitution pattern affects the electronic environment of the molecule, leading to distinct reactivity compared to its para isomer. This difference has allowed 2-chlorobenzoyl chloride to be used selectively in various synthetic routes, particularly in the creation of complex organic compounds.

In the pharmaceutical industry, 2-chlorobenzoyl chloride serves as a key intermediate in the synthesis of several active pharmaceutical ingredients (APIs). Its ability to react with amines and alcohols facilitates the formation of amides and esters, which are important functional groups in many drug molecules. The introduction of the acyl group helps in modifying the pharmacokinetics and bioavailability of drugs, thus enhancing their therapeutic effects. 2-Chlorobenzoyl chloride is especially useful in producing antibiotics, anti-inflammatory agents, and other biologically active compounds.

In agrochemicals, 2-chlorobenzoyl chloride is employed in the synthesis of herbicides and pesticides. The chlorine atom on the aromatic ring imparts stability and enhances the activity of the resulting compounds. These agrochemicals are widely used to protect crops from pests, contributing to higher agricultural yields and improved food security. The stability of 2-chlorobenzoyl chloride derivatives also ensures their effectiveness over longer periods in the field.

The compound also finds application in the production of polymers and specialty materials. Its reactivity allows it to participate in polymerization reactions, leading to the formation of high-performance polymers. These materials are valued for their strength, durability, and resistance to chemical degradation, making them useful in automotive, aerospace, and industrial applications.

2-Chlorobenzoyl chloride’s broad range of applications, from pharmaceuticals to agrochemicals and polymers, highlights its importance as a versatile reagent in modern organic synthesis. Its unique reactivity, due to the ortho-chlorine substitution, ensures its continued relevance in industrial chemistry.

References

2019. Condensation of 2-Halobenzoyl Chlorides and Ketones. Science of Synthesis.
URL: https://science-of-synthesis.thieme.com/app/text/?id=SD-114-00057

2020. Synthesis of Esketamine. Synfacts, 16(07).
DOI: 10.1055/s-0040-1707022

2022. Coupling Reactions with Acyl Halides. Science of Synthesis.
URL: https://science-of-synthesis.thieme.com/app/text/?id=SD-104-00790