2-Chloro-4-nitroaniline: Handling, Safety & Lab Use Guide

2-Chloro-4-nitroaniline is a halogenated aromatic amine reagent widely used as a key intermediate in the synthesis of dyes, pigments, agrochemicals, and pharmaceutical compounds.

CAS Number

121-87-9

Molecular Formula

C₆H₅ClN₂O₂

Molecular Weight

172.57 g/mol

Appearance

Yellow to orange crystalline solid

Melting Point

approx. 108–111 °C

Storage Condition

Store in a cool, dry, well-ventilated area away from light and moisture

SKU

C103975

Chemical Properties and Identification

2-Chloro-4-nitroaniline (CAS 121-87-9) is an aromatic amine bearing both a chloro substituent at the 2-position and a nitro group at the 4-position of the aniline ring. Its molecular formula is C₆H₅ClN₂O₂ with a molecular weight of 172.57 g/mol. The compound typically appears as a yellow to orange crystalline solid with a melting point in the range of approximately 108–111 °C. It is sparingly soluble in water but dissolves readily in common organic solvents such as ethanol, acetone, and dimethylformamide (DMF). The electron-withdrawing nitro group and the electron-withdrawing chloro group together reduce the basicity of the amino group compared with unsubstituted aniline, influencing its reactivity in condensation, diazotization, and nucleophilic aromatic substitution reactions.

Laboratory Handling and Personal Protective Equipment

2-Chloro-4-nitroaniline is classified as a harmful substance and should be handled with appropriate precautions at all times. Always work in a well-ventilated fume hood to minimize inhalation exposure to dust or vapors. The following personal protective equipment (PPE) is mandatory:

• Gloves: Chemical-resistant gloves (nitrile or neoprene, minimum 0.11 mm thickness) must be worn. Inspect gloves for integrity before each use.
• Eye Protection: Safety goggles or a face shield should be worn to prevent accidental eye contact.
• Lab Coat: A full-length lab coat or chemical-resistant apron is required to protect skin and clothing.
• Respiratory Protection: If ventilation is insufficient or if handling large quantities, a half-face respirator fitted with an organic vapor/P100 combination cartridge is recommended.

Avoid generating dust during weighing. Use a closed or enclosed balance or weigh inside the fume hood. In the event of skin or eye contact, immediately flush the affected area with copious amounts of water for at least 15 minutes and seek medical attention. Do not eat, drink, or smoke in areas where this compound is handled.

Storage, Stability, and Waste Disposal

Storage: Store 2-Chloro-4-nitroaniline in a tightly closed original container in a cool (recommended 2–25 °C), dry, and well-ventilated area, away from direct sunlight and sources of heat or ignition. Keep away from strong oxidizers, strong acids, and strong bases to prevent hazardous reactions. Containers should be clearly labeled and stored in a dedicated flammable/harmful chemical cabinet where applicable.

Stability: The compound is stable under recommended storage conditions. Prolonged exposure to light, moisture, or elevated temperatures may lead to discoloration or gradual degradation. Shelf life should be confirmed upon receipt; inspect for color changes or caking before use.

Waste Disposal: All waste containing 2-Chloro-4-nitroaniline must be disposed of in accordance with local, regional, and national regulations governing hazardous chemical waste. Do not pour down the drain or discharge into the environment. Collect waste in appropriately labeled, compatible containers and arrange collection through a licensed hazardous waste disposal contractor. Contaminated PPE and packaging should also be treated as hazardous waste.

Research Applications and Synthetic Utility

2-Chloro-4-nitroaniline serves as a versatile building block in organic synthesis across multiple research domains:

• Dye and Pigment Synthesis: As an aromatic amine, it can be diazotized and coupled with appropriate coupling components to produce azo dyes. The chloro substituent provides additional handles for further functionalization.
• Pharmaceutical Intermediates: The compound is used in the preparation of various pharmacologically active molecules, including antimicrobial and anti-inflammatory candidates, through reactions such as nucleophilic aromatic substitution (SNAr), reductive amination, and acylation.
• Agrochemical Research: It serves as a precursor in the synthesis of certain herbicides and pesticide intermediates.
• Heterocyclic Chemistry: The bifunctional nature of the molecule (amino and nitro groups with a reactive C–Cl bond) makes it useful for constructing nitrogen-containing heterocycles such as benzimidazoles, quinolines, and related scaffolds.
• Cross-Coupling Reactions: The aryl chloride functionality can participate in palladium-catalyzed cross-coupling reactions (e.g., Buchwald–Hartwig amination, Suzuki coupling) under appropriate conditions.

Researchers should optimize reaction conditions based on the specific transformation targeted and consult primary literature for detailed protocols.

Regulatory and Compliance Considerations

Research laboratories handling 2-Chloro-4-nitroaniline should be aware of the following regulatory considerations:

GHS Classification: The compound is generally classified under GHS as harmful if swallowed, harmful in contact with skin, and harmful if inhaled. It may also carry classifications related to aquatic toxicity. Users should consult the current Safety Data Sheet (SDS) supplied with the product for the authoritative hazard classification applicable in their jurisdiction.

Transport Regulations: When shipped, aromatic nitro compounds including this reagent may be subject to IATA, IMDG, or ADR transport regulations. Check the SDS and consult your institutional shipping officer before dispatch.

Environmental Regulations: Aromatic amines and nitroaromatics are subject to environmental monitoring and disposal regulations in many jurisdictions (e.g., EU REACH, US EPA guidelines). Ensure that waste disposal practices are compliant with applicable environmental laws.

Institutional Requirements: Prior to working with this compound, complete a local risk assessment and obtain any required approval from your institution's Environment, Health & Safety (EHS) office. Record all quantities used in your chemical inventory management system.

Frequently asked questions

What are the main uses of 2-Chloro-4-nitroaniline in research?

2-Chloro-4-nitroaniline is primarily used as an intermediate in the synthesis of azo dyes, pharmaceutical candidates, agrochemical compounds, and nitrogen-containing heterocycles. Its reactive amino, nitro, and aryl chloride groups make it a versatile scaffold for diverse transformations including diazotization, SNAr, and palladium-catalyzed coupling reactions.

How should 2-Chloro-4-nitroaniline be stored to maintain stability?

Store the compound in a tightly sealed original container at 2–25 °C in a cool, dry, and well-ventilated location away from direct light, moisture, and incompatible materials such as strong oxidizers, strong acids, and strong bases. Under these conditions the compound is stable; inspect for discoloration or caking before each use.

What personal protective equipment is required when handling 2-Chloro-4-nitroaniline?

Minimum PPE includes chemical-resistant gloves (nitrile or neoprene), safety goggles or face shield, and a full-length lab coat. All manipulations should be performed in a well-ventilated fume hood. A half-face respirator with organic vapor/P100 cartridge is recommended when ventilation is inadequate or when handling bulk quantities.

Is 2-Chloro-4-nitroaniline soluble in water?

2-Chloro-4-nitroaniline has very limited solubility in water. It dissolves readily in polar organic solvents such as ethanol, acetone, and DMF, which are the recommended solvents for preparing stock solutions for research applications.

How should waste containing 2-Chloro-4-nitroaniline be disposed of?

Collect all waste containing 2-Chloro-4-nitroaniline in clearly labeled, chemically compatible containers and arrange disposal through a licensed hazardous waste contractor in compliance with all applicable local, national, and regional regulations. Never pour this material down the drain or release it into the environment.

References

1. Royal Society of Chemistry. 2-Chloro-4-nitroaniline compound summary. ChemSpider database.
2. National Center for Biotechnology Information. 2-Chloro-4-nitroaniline. PubChem Compound Summary, CID 12092.
3. Globally Harmonized System of Classification and Labelling of Chemicals (GHS), United Nations, 9th revised edition.
4. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.