Sodium 2-Naphthol-7-sulfonate Hydrate: Key Facts & FAQs

Sodium 2-Naphthol-7-sulfonate Hydrate is a water-soluble, sulfonated aromatic compound used as a versatile intermediate in dye synthesis, coupling reactions, and analytical chemistry research.

Chemical Name

Sodium 2-Naphthol-7-sulfonate Hydrate

SKU / Product Code

S161176

Functional Class

Sulfonated naphthol; azo dye coupling component and analytical reagent

Solubility

Soluble in water due to the ionizable sulfonate group; sparingly soluble in most organic solvents

Storage Recommendation

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

Hydrate Form

Supplied as a hydrate; exact water content should be confirmed by lot-specific certificate of analysis

What Is Sodium 2-Naphthol-7-sulfonate Hydrate?

Sodium 2-Naphthol-7-sulfonate Hydrate is the sodium salt of 2-naphthol-7-sulfonic acid, supplied in its hydrated crystalline form. It belongs to the class of sulfonated hydroxynaphthalenes, where a hydroxyl group at the 2-position and a sulfonate group at the 7-position of the naphthalene ring system confer both phenolic reactivity and high water solubility.

This compound is historically associated with the Schaeffer's acid family of intermediates and is valued in synthetic chemistry for its well-defined reactivity at the hydroxyl-bearing aromatic ring. The sodium sulfonate moiety increases polarity and aqueous compatibility, making it amenable to reactions carried out in aqueous or mixed-solvent systems.

Key Properties and Specifications

The compound features a bicyclic naphthalene core with two principal functional groups: a phenolic –OH and a sulfonate –SO₃Na. These groups together govern its chemical behavior, including azo-coupling at the activated positions ortho and para to the hydroxyl group.

As a hydrate, the exact degree of hydration should be verified from the lot-specific Certificate of Analysis (CoA) provided by Aladdin Scientific, as water content may influence gravimetric calculations in quantitative experiments. Researchers should account for the hydrate correction factor when preparing solutions of defined molarity.

Purity grade and exact melting point or spectral data are lot-dependent; always consult the CoA for S161176 prior to use in sensitive assays.

Research Applications

Azo dye synthesis: Sodium 2-Naphthol-7-sulfonate Hydrate is a classical coupling component in the manufacture and study of azo colorants. It reacts with diazonium salts to produce water-soluble azo dyes that have been explored in textile, biological staining, and analytical contexts.

Analytical chemistry: Sulfonated naphthols are used as chromogenic reagents and indicators in complexometric and colorimetric methods, taking advantage of the intense color change upon azo-bond formation or metal coordination.

Synthetic intermediates: The compound serves as a building block for more complex polycyclic aromatic architectures and sulfonated ligands in coordination chemistry research.

Model substrate studies: Its well-characterized UV-visible absorption and fluorescence properties make it useful as a model compound in photochemical and environmental fate studies.

Safe Handling, Storage, and Disposal

Personal protective equipment: Use appropriate PPE including gloves, laboratory coat, and eye protection when handling this reagent. Avoid inhalation of dust and contact with skin or eyes.

Storage: Store in a tightly sealed container in a cool, dry, well-ventilated location away from direct light and incompatible substances such as strong oxidizers and strong acids. The hydrated form should be protected from excessive moisture changes that could alter its composition.

Disposal: Dispose of this compound and its solutions in accordance with local, regional, and national regulations governing chemical waste. Do not discharge into drains or the environment without appropriate treatment.

Always consult the Safety Data Sheet (SDS) for S161176 before first use. The SDS is available through Aladdin Scientific upon request or via the product page.

Ordering and Availability

Sodium 2-Naphthol-7-sulfonate Hydrate is available from Aladdin Scientific under SKU S161176. Researchers can place orders directly through the Aladdin Scientific website, by contacting your regional sales representative, or through approved institutional procurement channels.

For bulk quantities, custom pack sizes, or specific purity requirements, please reach out to Aladdin Scientific's technical sales team. Certificate of Analysis and Safety Data Sheet documents are available upon request for every lot.

For questions about stock availability, lead times, or volume pricing, contact Aladdin Scientific customer service.

Frequently asked questions

What is Sodium 2-Naphthol-7-sulfonate Hydrate used for in research?

It is primarily used as a coupling component in azo dye synthesis, reacting with diazonium salts to form water-soluble colored products. It also serves as an analytical chromogenic reagent, a synthetic intermediate for sulfonated aromatic compounds, and a model substrate in photochemical or environmental studies.

How should I store Sodium 2-Naphthol-7-sulfonate Hydrate to maintain its integrity?

Store the compound in a tightly sealed container in a cool, dry, and well-ventilated area, protected from light and away from strong oxidizers or acids. Because it is supplied as a hydrate, avoid conditions of extreme humidity change that could alter its water content and affect gravimetric accuracy in solution preparation.

How do I account for the hydrate form when preparing a molar solution?

You must use the molecular weight of the hydrated form (not the anhydrous free acid) when calculating the mass needed for a target molar concentration. Confirm the exact degree of hydration and molecular weight from the lot-specific Certificate of Analysis for S161176 before performing any stoichiometric calculations.

Is Sodium 2-Naphthol-7-sulfonate Hydrate soluble in organic solvents?

Due to the ionic sulfonate group, this compound is primarily water-soluble and has limited solubility in most common organic solvents. Researchers requiring organic-phase reactions may need to consider solubility testing in polar aprotic solvents such as DMSO or DMF, though compatibility should be verified experimentally.

Where can I find the Safety Data Sheet and Certificate of Analysis for S161176?

The Safety Data Sheet (SDS) and Certificate of Analysis (CoA) for Sodium 2-Naphthol-7-sulfonate Hydrate (S161176) are available through the Aladdin Scientific product page or upon request from customer service. Always review these documents before first use to ensure safe handling and to verify lot-specific quality parameters.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed. Wiley-Interscience, 1992. (General reference for azo coupling chemistry of naphthols.)
2. Zollinger, H. Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments, 3rd ed. Wiley-VCH, 2003. (Reference for sulfonated naphthol coupling components in azo dye manufacture.)
3. Aladdin Scientific. Product Page and Certificate of Analysis for Sodium 2-Naphthol-7-sulfonate Hydrate, SKU S161176. (Lot-specific physicochemical data.)

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