Quinizarin (1,4-Dihydroxyanthraquinone) molecular structure — anthraquinone with two hydroxyl groups, C14H8O4, CAS 81-64-1

1,4-Dihydroxyanthraquinone (Quinizarin)

CAS NO. 81-64-1

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Quinizarin Dye dye intermediate Solvent Dyes

Product Description

Applications

Parameter	Industrial Grade Specification
English Name	Quinizarin (1,4-Dihydroxyanthraquinone)
Common Synonyms	1,4-Dihydroxyanthraquinone; 1,4-DHAQ; Quinizarine; 1,4-dihydroxyanthracene-9,10-dione; Colour Index 58050; C.I. Solvent Orange 86
CAS Number	81-64-1
EC Number	201-368-7
Colour Index Number	C.I. 58050
Molecular Formula	C₁₄H₈O₄
Molecular Weight	240.21 g/mol
Appearance	Deep red to yellow-red crystalline solid; orange-red needles or plates depending on recrystallization solvent
Melting Point	approximately 196 °C
Flash Point	approximately 222 °C
Assay (Purity)	≥ 96% (Industrial) ≥ 98% (High-Purity)
Solubility	Moderately soluble in ethanol (red color); soluble in ether (brown color with yellow fluorescence); soluble in aqueous alkalies and ammonia (violet color); soluble in boiling glacial acetic acid; insoluble in water
Standard Packaging	25 kg fiber drum with PE inner liner (alternative packaging available on request)
EU CLP Classification	Aquatic Acute 1 (H400), Aquatic Chronic 1 (H410) — No human-health hazard classification
Quality Documentation	Certificate of Analysis (CoA), Safety Data Sheet (SDS), Technical Data Sheet (TDS) issued per lot

Lot-specific Certificate of Analysis (CoA) is provided with each shipment. Safety Data Sheet (SDS) and Technical Data Sheet (TDS) available on request. Quinizarin carries an aquatic-hazard classification (Aquatic Acute 1, H400; Aquatic Chronic 1, H410) and must be stored, handled, and disposed of in accordance with applicable environmental regulations. The substance is not listed under California Proposition 65, the REACH SVHC Candidate List, or any harmonised CLP classification for human-health endpoints. Suitability for any specific downstream synthesis or finished application is the responsibility of the end formulator.

Quinizarin (1,4-Dihydroxyanthraquinone, C.I. 58050, CAS 81-64-1) — Application Areas

Quinizarin (1,4-DHAQ, also known as 1,4-Dihydroxyanthraquinone or C.I. Solvent Orange 86; CAS 81-64-1) is a deep red to yellow-red crystalline anthraquinone-class compound with a molecular weight of 240.21 g/mol and a melting point of approximately 196 °C. As a planar dihydroxyanthraquinone, it serves as a key upstream building block in the synthesis of anthraquinone disperse, acid, and vat dyes, and is itself used directly as an oil-soluble industrial colorant under its Colour Index Solvent Orange 86 identity. Typical application areas are summarized below.

• Anthraquinone Dye Synthesis Intermediate

Quinizarin is the key upstream starting material in the synthesis of multiple anthraquinone-class dyes. The 1,4-dihydroxy substitution pattern enables direct condensation with primary amines to install 1,4-bis(alkylamino) chromophores, the foundation of an entire family of disperse, acid, and vat dyes that has been used in industrial dye manufacturing for several decades. Selection of the appropriate grade (96% industrial or 98% high-purity) depends on the color and impurity tolerance of the downstream synthesis.

End Products: C.I. Disperse Blue 60, C.I. Disperse Blue R, C.I. Disperse Blue SW, acid anthraquinone violet R, acid anthraquinone pure blue SG, acid anthraquinone green G.

• Direct Industrial Coloration (under C.I. Solvent Orange 86 identity)

Under its Colour Index Solvent Orange 86 identity, Quinizarin is also used directly as an oil-soluble red-orange industrial colorant. It is soluble in ethanol, ether, and boiling glacial acetic acid, gives a characteristic violet color in alkaline media, and has historical use in industrial hydrocarbon coloration and lubricant tinting programs that have been established for several decades. Compatibility, addition level, and end-product qualification are the buyer's responsibility.

End Products: industrial hydrocarbon coloration concentrates, lubricant tinting fluids, paraffin and stearic-acid wax coloration, decorative industrial smoke colorant formulations.

• Specialty Chemistry & Research Applications

The planar dihydroxyanthraquinone scaffold and its color change in alkaline media make Quinizarin a long-established laboratory reagent. It has been used as a long-wavelength fluorescence reporter, a pH indicator in alkaline systems, a building block in organic-electronics research, and a chemical analytical reference. End-use suitability, scale, and downstream qualification are the user's responsibility.

End Products: laboratory analytical reagents, long-wavelength fluorescent probe reference compounds, pH indicator preparations (alkaline systems), organic-electronics research materials.

• Lake Pigment & Other Historical Industrial Uses

Quinizarin has been used historically to form calcium and barium lake pigments for decorative coating and printing-ink applications, and as a synthetic intermediate in several other established industrial-chemistry programs of long standing. Material is supplied with a lot-specific Certificate of Analysis and Safety Data Sheet; suitability for any specific finished application — including any downstream dye synthesis, pigment formulation, or industrial coloration program — is the responsibility of the end formulator and must be qualified under the buyer's own regulatory framework.

End Products: calcium and barium anthraquinone lake pigments, decorative coating pigment concentrates, intermediate building blocks for established anthraquinone-chemistry programs.

Product Description

Applications

1,4-Dihydroxyanthraquinone (Quinizarin)

Quinizarin (1,4-Dihydroxyanthraquinone, C.I. 58050, CAS 81-64-1) — Application Areas

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