Resorcine
[CAS# 108-46-3]

Identification

• Classification: API >> Synthetic anti-infective drugs >> Disinfectant antiseptic
• Name: Resorcine
• Synonyms: 1,3-Dihydroxybenzene; 1,3-Benzenediol
• Molecular Formula: C₆H₆O₂
• Molecular Weight: 110.11
• CAS Registry Number: 108-46-3
• EC Number: 203-585-2
• FEMA: 3589
• SMILES: C1=CC(=CC(=C1)O)O

Properties

• Solubility: 1000 mg/ml (H2O), 111 mg/ml (DMSO) (Expl.)
• Density: 1.3±0.1 g/cm³, Calc.^*, 1.272 g/mL (Expl.)
• Melting point: 109-112 °C (Expl.)
• Index of Refraction: 1.612, Calc.^*
• Boiling Point: 280.0 °C (760 mmHg), Calc.^*, 339 °C (Expl.)
• Flash Point: 131.9±12.8 °C, Calc.^*, Melting point

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

Safety Data

• Hazard Symbols: GHS07;GHS08;GHS09 Danger
• Risk Statements: H302-H315-H317-H319-H370-H371-H400
• Safety Statements: P260-P261-P264-P264+P265-P270-P272-P273-P280-P301+P317-P302+P352-P305+P351+P338-P308+P316-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	1	H370
Specific target organ toxicity - single exposure	STOT SE	2	H371
Skin sensitization	Skin Sens.	1B	H317
Serious eye damage	Eye Dam.	1	H318
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	3	H301
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Flammable solids	Flam. Sol.	2	H228
Eye irritation	Eye Irrit.	2A	H319
Specific target organ toxicity - repeated exposure	STOT RE	1	H372

• Transport Information: UN 2876

Discovery and Applications

Resorcinol, also known as resorcin or 1,3-benzenediol, is an organic compound with the molecular formula C₆H₄(OH)₂. It consists of a benzene ring with two hydroxyl groups located at the 1 and 3 positions. Resorcinol is a white, crystalline solid that is soluble in water, alcohol, and ether. It exhibits weakly acidic properties due to the presence of the phenolic hydroxyl groups.

The compound was first isolated in the 19th century by German chemist Heinrich Hlasiwetz through the distillation of natural resin substances such as galbanum and asafoetida. It was later synthesized from meta-benzenedisulfonic acid and through the alkali fusion of m-hydroxybenzenesulfonic acid. These methods were refined to improve the yield and purity of resorcinol, making it more accessible for industrial and laboratory use.

Resorcinol is widely used in the manufacture of resins, particularly in the production of resorcinol-formaldehyde resins. These resins are valued for their adhesive strength, water resistance, and chemical stability and are used in wood bonding, rubber compounding, and abrasive product manufacture. In the rubber industry, resorcinol plays a crucial role as an adhesion promoter for reinforcing materials like nylon or polyester in tire manufacturing, forming a chemical bridge between the rubber and the reinforcing fabric.

Another significant application of resorcinol is in the synthesis of dyes and pigments. It serves as an intermediate in the preparation of azo dyes, fluorescein, eosin, and phthalein dyes. These compounds are utilized in textiles, inks, and biological staining due to their vivid colors and ability to bind selectively to biological materials. The chromogenic properties of resorcinol derivatives also enable their use in analytical chemistry for colorimetric assays.

In the pharmaceutical and personal care industries, resorcinol is used for its antiseptic, keratolytic, and disinfectant properties. It has been included in topical acne treatments, psoriasis preparations, and antifungal creams. Its ability to break down the stratum corneum of the skin enhances the efficacy of therapeutic agents by promoting penetration. However, its use in cosmetics and over-the-counter medications is regulated due to potential toxicity with prolonged or excessive exposure.

Resorcinol is also employed in analytical chemistry as a reagent for identifying and quantifying specific substances. For example, it reacts with sugars in acidic conditions to form colored complexes, which are useful in spectrophotometric analyses. This reaction, known as the resorcinol test, is especially applied in the detection of ketoses and sialic acids in biochemical research.

Additionally, resorcinol has been studied in the synthesis of pharmaceuticals and agrochemicals. Its aromatic and hydroxyl functionalities make it a versatile building block in organic synthesis. It has been used to construct compounds with antibacterial, antifungal, and anti-inflammatory properties, although resorcinol itself is not typically administered systemically due to its potential toxicity.

Toxicologically, resorcinol may cause skin and eye irritation, and prolonged exposure can lead to systemic effects such as methemoglobinemia or thyroid dysfunction. Therefore, it is handled with caution in industrial settings, and its concentration in consumer products is strictly controlled. Regulatory agencies such as the European Chemicals Agency and the United States Food and Drug Administration provide guidelines for its safe use.

Overall, resorcinol is a well-established chemical compound with a broad spectrum of industrial, pharmaceutical, and analytical applications. Its discovery and synthetic accessibility have made it a key intermediate in both research and commercial manufacturing processes, with continued relevance in various scientific and technological fields.

References

2024. Sensitive electrochemical sensor for dihydroxybenzene isomers based on single-atom Cu catalyst derived from Cu-ZIF-8. Research on Chemical Intermediates, 50(12), 5597-5612.
DOI: 10.1007/s11164-024-05469-1

1881. Das Dipropylresorcin und einige Derivate desselben. Monatshefte für Chemie, 2(1), 614-621.
DOI: 10.1007/bf01517068

1881. Über Resorcinfarbstoffe. Monatshefte für Chemie, 2(1), 662-672.
DOI: 10.1007/bf01517116