3-Chloro-2-methylbenzoic acid
[CAS# 7499-08-3]

Identification

• Classification: Chemical reagent >> Organic reagent >> Aromatic acid
• Name: 3-Chloro-2-methylbenzoic acid
• Synonyms: 3-Chloro-o-toluic acid
• Molecular Formula: C₈H₇ClO₂
• Molecular Weight: 170.59
• CAS Registry Number: 7499-08-3
• EC Number: 626-731-0
• SMILES: CC1=C(C=CC=C1Cl)C(=O)O

Properties

• Density: 1.3±0.1 g/cm³, Calc.^*
• Melting point: 163-166 °C (expl.)
• Index of Refraction: 1.573, Calc.^*
• Boiling Point: 290.9±20.0 °C (760 mmHg), Calc.^*
• Flash Point: 129.7±21.8 °C, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

3-Chloro-2-methylbenzoic acid is an aromatic carboxylic acid compound with the chemical formula C8H7ClO2. It is characterized by a chlorine atom at the 3-position and a methyl group at the 2-position on the benzene ring. This compound is a member of the family of halogenated benzoic acids, which are widely studied and used in various industrial applications. The discovery of 3-chloro-2-methylbenzoic acid is linked to the broader exploration of chlorinated aromatic compounds, which have found applications in pharmaceuticals, agrochemicals, and materials science.

The history of the discovery of 3-chloro-2-methylbenzoic acid is less documented in the public domain compared to more widely known compounds. However, its synthesis likely occurred as part of efforts in the mid-20th century to investigate chlorinated and substituted aromatic compounds for their potential biological and chemical activities. These compounds were of interest due to their reactivity and the possibility of creating new materials with specialized properties.

3-Chloro-2-methylbenzoic acid is used as an intermediate in the synthesis of various chemical products, particularly in the production of agrochemicals and pharmaceuticals. The presence of both the chlorine and methyl groups on the benzene ring imparts specific reactivity to the molecule, making it suitable for use in reactions that require such substitutions. For instance, it can be used as a building block for the synthesis of herbicides and pesticides. Chlorine atoms in aromatic compounds are often introduced to enhance the stability and lipophilicity of the molecule, which improves its efficacy in biological applications.

One of the key applications of 3-chloro-2-methylbenzoic acid is in the production of pharmaceuticals. This compound serves as a precursor to the synthesis of certain active pharmaceutical ingredients, where the chlorinated and methylated benzoic acid backbone is modified to achieve the desired biological activity. For example, derivatives of 3-chloro-2-methylbenzoic acid have been studied for their potential anti-inflammatory and analgesic properties, which are useful in the development of pain-relief medications and treatments for inflammatory disorders.

In addition to its use in pharmaceuticals, 3-chloro-2-methylbenzoic acid is also employed in the production of fine chemicals and specialty materials. The chlorinated structure of this compound makes it useful in the creation of polymers, resins, and other materials that require specific chemical properties, such as increased chemical resistance or improved thermal stability. The compound’s reactivity also makes it a versatile intermediate for producing various derivatives with enhanced functionality for specific industrial needs.

Another significant application of 3-chloro-2-methylbenzoic acid lies in the development of agrochemicals. It can be used in the synthesis of herbicides and pesticides that are effective in controlling unwanted plants or pests. The halogenation of aromatic compounds is a well-known strategy in the design of such chemicals, as the chlorine atom can improve the stability and bioactivity of the molecule. As agricultural practices continue to evolve, the demand for efficient and environmentally friendly agrochemicals remains strong, and compounds like 3-chloro-2-methylbenzoic acid play a role in meeting this demand.

In terms of chemical reactivity, 3-chloro-2-methylbenzoic acid undergoes a variety of reactions typical of carboxylic acids. These include esterification, amidation, and coupling reactions, which are often employed to modify the compound for use in various formulations. The chlorine atom at the 3-position makes this compound reactive in electrophilic aromatic substitution reactions, facilitating the introduction of other functional groups that can enhance its properties or further diversify its applications.

Research continues into the use of 3-chloro-2-methylbenzoic acid in specialized fields, particularly in drug development and materials science. Its relatively simple structure makes it an attractive starting material for the synthesis of complex molecules, while its halogenated and methylated substituents offer unique properties that are valuable for various chemical processes. As new methods of synthesis and functionalization are developed, the role of 3-chloro-2-methylbenzoic acid in industrial and pharmaceutical chemistry may expand further.

References

1992. Utilization of 3-chloro-2-methylbenzoic acid by Pseudomonas cepacia MB2 through the meta fission pathway. Applied and Environmental Microbiology, 58(8).
DOI: 10.1128/aem.58.8.2501-2504.1992

2011. Degradation of 2-chlorotoluene by Rhodococcus sp. OCT 10. Applied Microbiology and Biotechnology, 92(2).
DOI: 10.1007/s00253-011-3543-5