5-Nitro-2-aminophenol vs Other Aminophenol Derivatives: What's the Difference?

Buyers often compare 2-amino-5-nitrophenol vs 2-amino-4-nitrophenol because the names look close and the molecular formula can be the same. But these compounds are different isomers with different CAS numbers, melting points, applications, and customs details. This guide helps purchasing teams avoid ordering the wrong aminophenol derivative.

Quick Definition: What Are Aminophenol Derivatives?

Aminophenol derivatives are aromatic compounds with amino and hydroxyl groups on a benzene ring. Nitro-aminophenols add a nitro group, and the position of that nitro group creates different isomers. The CAS number is the safest identifier because supplier synonyms are not always used consistently.

The Structural Difference: Nitro Position Matters

5-NAP has the nitro group at the 5-position, while 2-amino-4-nitrophenol places the nitro group at a different position. That positional change affects melting point, color route, safety profile, and sometimes HS classification.

• Same formula does not mean same compound.

• A similar synonym can hide a different CAS.

• Application matching should start with CAS, not with trade name.

Property Comparison: CAS, Melting Point, and More

A melting point mismatch is not final proof by itself, but it is a strong warning to stop and re-check CAS, hydration form, and COA identity.

Which Isomer for Which Application?

Do not approve substitution simply because the supplier says the material is an aminophenol derivative. For dyes, the wrong isomer can change shade. For pharma synthesis, it can break the route.

How to Verify the CAS Before You Order

1. Write the required CAS number into the RFQ.

2. Ask the supplier to repeat the CAS on the quotation, COA, label, and SDS.

3. Compare melting point and assay against the expected compound.

4. Check synonyms against a trusted database.

5. Ask your customs broker to confirm the HS classification before shipment.

India Procurement: Grades, Pricing, and Suppliers

Indian dye and pharma-intermediate buyers often compare local inventory, catalog suppliers, and China-origin bulk supply. The lowest quote is not useful if the CAS is wrong or if documents do not match customs and internal QC requirements.

• Use samples to confirm shade or reaction performance.

• Keep CAS and batch number consistent across all documents.

• Ask for India shipment experience when buying from overseas suppliers.

• Separate dye-grade, pharma R&D, and trading-grade requirements.

FAQ

Are 5-NAP and 2-amino-4-nitrophenol interchangeable?

No. They are different compounds and should not be substituted without route validation.

What is the fastest mistake-prevention check?

Confirm the CAS number on every document before payment and shipment.

Why do melting points differ between suppliers?

Differences can come from isomer, hydration form, impurity, or test method. Treat a large mismatch as a reason to investigate.

Conclusion

Aminophenol derivatives can look deceptively similar on a quotation. To avoid wrong-CAS purchases, match the application to the exact CAS, verify melting point and COA data, and confirm customs details before shipment.

View AquaChem 5-NAP CAS 121-88-0 details

Why Name Similarity Creates Real Purchase Risk

Chemical purchasing teams often work from old formulas, translated names, supplier catalogs, and customs descriptions. In that environment, a small name difference can become a real shipment mistake. '2-amino-5-nitrophenol' and '2-amino-4-nitrophenol' look close, and both belong to a similar chemical family, but they are not interchangeable purchasing targets.

The risk increases when a buyer asks several traders for a quote and receives offers written in different synonym styles. One supplier may use 5-NAP, another may use 2-hydroxy-4-nitroaniline, and another may shorten the name. The CAS number is the common language that cuts through that inconsistency.

CAS Verification Workflow for Procurement Teams

A wrong-CAS prevention workflow should be written into the sourcing process. It does not need to be complicated; it only needs to be consistent. The person requesting the quote, the supplier, the QC reviewer, and the customs broker should all be looking at the same identifier.

1. Put the required CAS in the RFQ subject line and body.

2. Reject quotations that do not state the CAS clearly.

3. Check that COA, SDS, invoice, and label use the same CAS.

4. Compare melting point and molecular weight against the expected profile.

5. Run a sample test before approving a new supplier for bulk orders.

When to Escalate to Technical Review

Escalate the order to a chemist or QC lead when the synonym, CAS, melting point, HS code, or application does not line up. A technical review is also needed when the supplier proposes a substitute isomer because the requested product is out of stock. In dye chemistry, substitution can change shade. In synthesis chemistry, it can change the route entirely.

The safest long-tail purchasing content does not merely list isomers. It teaches the buyer when to stop the buying process and ask for technical confirmation. That is the core purpose of this comparison article.

A Practical Wrong-CAS Example

Imagine a buyer needs CAS 121-88-0 for a red azo dye intermediate route, but a supplier offers a similar aminonitrophenol with a lower melting point and a slightly different synonym. The shipment may still look like a brown or orange powder, and the molecular formula may not immediately reveal the mistake. The problem appears only when the reaction gives a different shade or the QC team notices that the COA does not match the requested compound.

That example is why the article's message should be repetitive in a useful way: match CAS first, then check properties, then validate the application. The buyer is not being difficult by asking for this evidence. They are preventing a predictable procurement failure.