For professionals in the chemical, pharmaceutical, and related industries, selecting the right raw materials is foundational to successful product development and manufacturing. 4-Nitrobenzenesulfonyl Chloride (CAS 98-74-8) is a critical intermediate, and understanding its key specifications is vital for informed purchasing decisions. This guide focuses on the essential parameters that B2B buyers should consider when evaluating suppliers, particularly those in China.

1. Chemical Identity and Purity

The most fundamental specification is the accurate identification of the chemical and its purity. For 4-Nitrobenzenesulfonyl Chloride:

• CAS Number: 98-74-8. This unique identifier ensures you are procuring the correct compound and helps avoid confusion with similar chemicals.
• Chemical Name: 4-Nitrobenzenesulfonyl Chloride. Synonyms like 4-Nitrobenzene-1-sulfonyl chloride or p-Nitrobenzenesulfonyl chloride may also be encountered.
• Molecular Formula: C6H4ClNO4S. This defines the elemental composition.
• Molecular Weight: Approximately 221.62 g/mol.
• Assay (Purity): This is arguably the most critical specification, especially for pharmaceutical applications. Manufacturers typically offer 4-Nitrobenzenesulfonyl Chloride with an assay of ≥ 99.5% MIN. For less stringent applications, lower purities like 90% or 97% might be available, but it's crucial to match the purity to the intended use. The Certificate of Analysis (CoA) should detail the exact purity and identify any significant impurities.

2. Physical Characteristics

Visual and physical properties provide immediate indicators of product quality and handling requirements:

• Appearance: Typically described as a yellow powder or yellow crystalline solid. Significant deviations in color might suggest degradation or contamination.
• Melting Point: Literature values often cite a melting point around 75°C. This can be a useful parameter for confirming identity and purity.
• Moisture Content: 4-Nitrobenzenesulfonyl Chloride is moisture-sensitive. Specifications may include a maximum moisture content, often around 1% MAX. Proper handling and storage conditions are essential to prevent hydrolysis.

3. Application Relevance

Understanding the intended use helps in prioritizing specifications:

• Pharmaceutical Intermediates: For API synthesis, stringent purity, low impurity levels, and compliance with pharmacopoeia standards (USP, BP, EP, FCC) are paramount. Manufacturers catering to this sector usually highlight these certifications.
• Dye Intermediates: While purity is still important, specific impurity profiles or trace elements might be critical depending on the dye color and application.
• General Organic Synthesis: Requirements may be less stringent, allowing for a broader range of purity levels depending on the complexity of the downstream reaction.

4. Packaging and Handling

Practical specifications for logistics and on-site use include:

• Packing: Commonly supplied in 25kg drums. Buyers should confirm if this is suitable for their storage and handling infrastructure. Bulk purchase inquiries can often lead to custom packaging solutions.
• Storage Conditions: Due to moisture sensitivity, storage in a cool, dry, and well-ventilated area, away from incompatible materials, is essential. Suppliers often recommend storing below +30°C.

5. Supplier Information and Compliance

• Manufacturer Location: Buyers often seek manufacturers in China due to cost advantages and large-scale production capabilities. Verifying the manufacturer’s reputation and capabilities is key.
• Certifications: GMP, SGS, ISO certifications indicate a commitment to quality management systems.

When you are ready to buy 4-Nitrobenzenesulfonyl Chloride, engaging with a supplier who provides clear, detailed specifications and readily available technical support is crucial. By focusing on these key parameters, procurement professionals can ensure they source high-quality intermediates that meet their exact industrial needs.