Product: p-Nitrophenol (4-Nitrophenol, Para-Nitrophenol)

CAS Number: 100-02-7

Chemical Formula: C₆H₅NO₃

Molecular Weight: 139.11 g/mol

P-Nitrophenol (PNP), commonly referred to as 4-nitrophenol or para-nitrophenol (PNP), is a widely utilized nitroaromatic compound and key organic intermediate in chemical manufacturing. This high-quality product offers consistent performance as a versatile building block for synthesizing valuable downstream compounds across multiple industrial sectors.

Key Properties

  • Appearance: White to light yellow, pale yellow, or colorless to slightly yellowish crystalline solid/powder (may appear greenish in some grades)
  • Melting Point: 110–115 °C (typically 113–114 °C)
  • Boiling Point: Approximately 279 °C (with decomposition)
  • Density: About 1.48–1.50 g/cm³ at 20 °C
  • Solubility: Moderately soluble in water (≈10–16 g/L at 15–25 °C); highly soluble in hot water, ethanol, ether, acetone, and alkaline solutions
  • Purity: Typically ≥99% (GC or titration methods)
  • Other Characteristics: Functions as a pH indicator (colorless below pH ≈5.4, yellow above pH ≈7.5); sensitive to light and air; toxic by ingestion and skin absorption

Primary Applications

p-Nitrophenol serves as an essential precursor and intermediate in numerous high-demand industries:

  • Pharmaceutical Industry — Key starting material for synthesizing analgesics and antipyretics such as acetaminophen (paracetamol); also used in production of other active pharmaceutical ingredients and related derivatives.
  • Agrochemical Industry — Major intermediate in manufacturing organophosphorus insecticides (e.g., methyl parathion, ethyl parathion), fungicides, herbicides, and other pesticides.
  • Dye and Pigment Industry — Critical building block for producing azo dyes, sulfur dyes, acid dyes, and various colorants; contributes to vibrant and stable dye formulations.
  • Other Industrial Uses — Employed in leather darkening processes, rubber chemicals, antioxidants, photographic chemicals, and as a pH indicator in analytical and laboratory applications.

Product Advantages-P-Nitrophenol (PNP)

  • High reactivity due to nitro and phenolic functional groups
  • Reliable purity suitable for pharmaceutical, agrochemical, and dye-grade applications
  • Established role in large-scale industrial synthesis
  • Versatile platform for further chemical derivatization and functionalization

Handling and Storage Recommendations-P-Nitrophenol (PNP)

Use appropriate personal protective equipment (gloves, goggles, protective clothing) and handle in a well-ventilated area or under fume hood. Avoid skin contact, inhalation, and ingestion — the compound is toxic and irritating. Store in tightly sealed containers in a cool, dry, dark place, away from strong oxidizers, bases, acids, and sources of ignition. Protect from light and moisture to prevent degradation or discoloration.

Frequently Asked Questions (FAQs)

What is the primary use of p-nitrophenol (CAS 100-02-7)?

It is most commonly used as a key intermediate in the production of acetaminophen (paracetamol), organophosphorus insecticides, fungicides, and various dyes.

Is p-nitrophenol the same as 4-nitrophenol?

Yes, p-nitrophenol, 4-nitrophenol, and para-nitrophenol all refer to the same compound — the para isomer of nitrophenol.

How does p-nitrophenol function as a pH indicator?

In solution, it is colorless in acidic conditions (below pH ≈5.4) and turns bright yellow in neutral to alkaline conditions (above pH ≈7.5), making it useful in titrations and analytical chemistry.

What industries rely most heavily on p-nitrophenol?

The main sectors are pharmaceuticals (for analgesics), agrochemicals (pesticides and fungicides), and dyes/pigments manufacturing.

How should p-nitrophenol be stored to maintain quality?

Store in airtight, light-resistant containers in a cool, dry environment. Exposure to light, air, or moisture can cause discoloration or reduced purity over time.

Is p-nitrophenol used in leather processing?

Yes, it is applied in some processes to darken or treat leather, in addition to its primary roles in synthesis.

What is the typical purity of commercial p-nitrophenol?

High-grade material is usually ≥99% pure, meeting requirements for pharmaceutical intermediates, agrochemicals, and specialty chemical production.

Does p-nitrophenol require special safety precautions?

Yes — it is toxic if swallowed or absorbed through skin, and can cause severe irritation. Always use PPE, ensure good ventilation, and follow local regulations for handling hazardous substances.

What is the CAS number for p-nitrophenol?

The CAS registry number is 100-02-7.

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