9-Anthracenecarboxylic acid
[CAS 723-62-6]

Identification

• Classification: Chemical reagent >> Organic reagent >> Polycyclic compound
• Name: 9-Anthracenecarboxylic acid
• Synonyms: 9-Anthroic acid; Anthracene-9-carboxylic acid
• Molecular Formula: C₁₅H₁₀O₂
• Molecular Weight: 222.24
• CAS Registry Number: 723-62-6
• EC Number: 211-964-9
• SMILES: C1=CC=C2C(=C1)C=C3C=CC=CC3=C2C(=O)O

Properties

• Density: 1.3±0.1 g/cm³ Calc.^*
• Melting point: 213 - 217 °C (Expl.)
• Boiling point: 467.5±14.0 °C 760 mmHg (Calc.)^*
• Flash point: 206.1±14.8 °C (Calc.)^*
• Solubility: Soluble 10 mM in ethanol, 100 mM in DMSO (Expl.)
• Index of refraction: 1.743 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS06;GHS07 Danger
• Risk Statements: H301-H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P316-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	3	H301

chemBlink Chemical Story

9-Anthracenecarboxylic acid, CAS 723-62-6, is also called anthracene-9-carboxylic acid or 9-anthroic acid. PubChem records the molecular formula C15H10O2 and describes the molecule as anthracene carrying a carboxyl group at the central 9-position. This arrangement combines the extended conjugated system of anthracene with a carboxylic-acid group that can be converted into salts, esters, amides and other derivatives.

Anthracene is a classic polycyclic aromatic chromophore. Its three fused benzene rings absorb ultraviolet light and support fluorescence and photochemical reactions. Attaching COOH at the 9-position introduces a polar, chemically transformable group at one of anthracene's most characteristic positions without removing the large aromatic surface. This makes 9-anthracenecarboxylic acid useful as a starting point for preparing functional anthracene derivatives for photochemical, fluorescence and materials studies.

The carboxyl group also provides a convenient way to connect the anthracene unit to other molecular systems. Esterification can link it to alcohol-containing molecules or polymers, while amide formation can attach it to amines. Such transformations allow the anthracene chromophore to be incorporated into larger architectures while retaining its recognizable optical and aromatic properties.

9-Anthracenecarboxylic acid also has a distinct history in physiology. PubChem and MeSH identify 9-anthroic acid as a chloride-channel blocker. It has been used experimentally as a pharmacological tool in studies of chloride conductance and ion-channel function. This research use should not be confused with an approved therapeutic indication: the compound is primarily a laboratory probe rather than a medicine.

The molecule therefore sits at an unusual intersection. To a materials chemist, it is a functionalized fluorescent aromatic building block; to a physiologist, it is a classical chloride-channel inhibitor used to perturb membrane transport experimentally. Both roles arise from the same compact structure: a large anthracene surface plus one strategically placed carboxyl group.

References:
1. PubChem, 9-Anthracenecarboxylic acid, CID 2201, CAS 723-62-6.
2. NCBI MeSH, 9-Anthroic acid.
3. Lakowicz JR. Principles of Fluorescence Spectroscopy. 3rd ed. Springer, 2006.

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