2-Bromophenol (Ortho-Bromophenol): Structure, Properties, and Applications

2-Bromophenol, also known as ortho-bromophenol, is an aromatic organic compound that consists of a bromine atom and a hydroxyl (-OH) group attached to a benzene ring in the ortho position (adjacent to each other). It is a halogenated phenol widely used in organic synthesis, pharmaceuticals, and as an intermediate in chemical industries.

Chemical Structure and Properties

Molecular Formula: C₆H₅BrO

Molecular Weight: 173.01 g/mol

IUPAC Name: 2-Bromophenol

CAS Number: 95-56-7

Physical Appearance: Colorless to pale yellow liquid or crystalline solid

Melting Point: 6-7°C

Boiling Point: 195-198°C

Density: 1.67 g/cm³

Solubility: Moderately soluble in water; soluble in organic solvents such as ethanol, ether, and chloroform

Odor: Phenolic odor

Synthesis of 2-Bromophenol

2-Bromophenol can be synthesized through various methods, including:

1. Electrophilic Substitution: Bromination of phenol using bromine (Br₂) or N-bromosuccinimide (NBS) in the presence of a catalyst such as iron (Fe) results in the formation of ortho- and para-bromophenol, with ortho isomer being a major product under controlled conditions.

2. Sandmeyer Reaction: The diazotization of 2-aminophenol followed by treatment with copper(I) bromide (CuBr) yields 2-bromophenol.

3. Grignard Reaction: The reaction of phenol with magnesium bromide in an organic solvent, followed by oxidation, can also yield 2-bromophenol.

Chemical Reactions

2-Bromophenol undergoes various chemical transformations, including:

• Nucleophilic Substitution: The bromine atom can be substituted by other nucleophiles, leading to derivatives useful in pharmaceutical and agrochemical synthesis.

• Coupling Reactions: It participates in Suzuki and Heck coupling reactions, forming biaryl compounds.

• Oxidation and Reduction: The hydroxyl (-OH) group can be oxidized to quinones or reduced under suitable conditions.

Applications

1. Pharmaceutical Industry: 2-Bromophenol serves as a key intermediate in the synthesis of drugs and biologically active compounds.

2. Agrochemical Industry: It is used in the formulation of pesticides and herbicides.

3. Dye Manufacturing: As a precursor in the production of dyes and pigments.

4. Flame Retardants: Some derivatives of 2-bromophenol are employed as flame retardants.

5. Analytical Chemistry: Used as a reagent in spectroscopic and chromatography applications.

Toxicity and Safety

2-Bromophenol is considered toxic and irritant, especially upon prolonged exposure. Safety precautions include:

• Handling in a well-ventilated area

• Wearing protective gloves and goggles

• Avoiding skin and eye contact

• Proper disposal as per environmental regulations

Conclusion

2-Bromophenol (ortho-bromophenol) is an important organic compound with diverse applications in chemical industries. Its unique structural properties enable its use in pharmaceuticals, agrochemicals, and material sciences. However, careful handling and adherence to safety protocols are necessary to mitigate its toxic effects. Chloromethyl Methyl Ether (CMME) is a colorless, flammable liquid commonly used as a reagent in organic synthesis.