Introduction
8-Hydroxyquinoline(CAS 148-24-3) is an important organic compound widely used across the pharmaceutical, chemical, and industrial sectors. As a derivative of quinoline, it contains both nitrogen and hydroxyl functional groups, giving it strong chelating, antioxidant, and antimicrobial properties. These unique features make 8-hydroxyquinoline a valuable multifunctional chemical with diverse applications ranging from metal ion complexing and corrosion inhibition to antiseptic formulations and polymer stabilization.
Chemically known as C₉H₇NO, 8-hydroxyquinoline can form stable complexes with various metal ions, including iron, zinc, and copper. This property makes it a key component in analytical chemistry, metal surface treatment, and pharmaceutical synthesis. In addition, its ability to inhibit oxidation and microbial growth extends its use to cosmetics, agriculture, and material preservation.
In this article, we’ll explore what 8-hydroxyquinoline is, its chemical structure and characteristics, and its main industrial applications. Understanding this versatile compound can help you unlock new solutions for formulation stability, corrosion prevention, and product performance.
What is 8-Hydroxyquinoline（CAS 148-24-3）?
8-Hydroxyquinoline (8-HQ) is a nitrogen-containing heterocyclic organic compound with the molecular formula C₉H₇NO. It is a derivative of quinoline, distinguished by the presence of a hydroxyl (-OH) group at the 8th position of the quinoline ring. This structure provides dual coordination sites: the hydroxyl oxygen and the nitrogen atom within the heterocyclic ring, enabling 8-hydroxyquinoline to form stable chelate complexes with a variety of metal ions such as Cu²⁺, Fe³⁺, Zn²⁺, and others.
The compound appears as white to cream-colored crystalline powder and is insoluble in water but soluble in organic solvents like ethanol and acetone. The unique metal-chelating properties of 8-hydroxyquinoline make it valuable in chemical analysis, pharmaceuticals as antimicrobial and fungicidal agents, and various industrial applications, including dye synthesis, preservatives in cosmetics, and corrosion inhibitors.
Discovered historically through chemical research on quinoline derivatives, 8-hydroxyquinoline plays important roles due to its ability to bind metals tightly, allowing it to be used in metal ion detection, disease treatment related to metal imbalances, and as a multifunctional agent with diverse bioactivities.
Chemical Identity
- Chemical Name:8-Hydroxyquinoline
- Chemical Formula: C9H7NO
- Molecular Weight: 145.16
- CAS Number: 148-24-3
- Appearance: White or pale yellow crystalline powder.
- Solubility: Freely soluble in ethanol, acetone, chloroform, benzene, and dilute acids; practically insoluble in water.
Key Characteristics and Functions of 8-Hydroxyquinoline（CAS 148-24-3）
Exceptional Metal Ion Chelating Ability
As a highly effective bidentate ligand, 8-Hydroxyquinoline (8-HQ) is primarily characterized by its ability to form highly stable metal chelates with a wide variety of metal ions. Through the synergistic action of its hydroxyl oxygen and nitrogen atoms, it can complex nearly all polyvalent metal ions, such as Fe3+ (Iron), Cu2+ (Copper), Zn2+ (Zinc), Al3+ (Aluminum), and Mg2+ (Magnesium). This property makes it a central reagent in analytical chemistry for the separation, detection, and quantification of metal ions, and the foundational basis for forming electron-transport layers like Alq3 in OLED materials.
Potent Antibacterial and Antifungal Activity (Antiseptic)
8-Hydroxyquinoline and its derivatives are well-known for their broad-spectrum antibacterial and antifungal activities. Its antimicrobial mechanism is largely attributed to its powerful metal chelating ability: it effectively sequesters trace metal ions (such as iron and copper) that are essential for microbial survival, thereby disrupting key enzyme systems and inhibiting the growth and reproduction of pathogens. This bioactivity leads to the use of 8-HQ in preservatives, disinfectants, and the pharmaceutical sector for treating skin and intestinal infections.
Antioxidant Performance
The molecular structure of 8-Hydroxyquinoline provides it with the capacity to scavenge free radicals, lending it significant antioxidant performance. It can effectively trap Reactive Oxygen Species (ROS), thereby preventing undesirable oxidation reactions and protecting sensitive organic substances. In industrial applications, 8-HQ is consequently used as a stabilizer and preservative to prevent oxidative degradation, which often leads to spoilage or discoloration in products such as oils, polymers, plastics, or certain aqueous formulations.
Fluorescence Behavior
In the field of analytical chemistry, 8-Hydroxyquinoline serves as an important fluorescence reagent. When 8-HQ forms complexes with specific metal ions (particularly under UV light irradiation), these complexes emit a characteristic fluorescence. This property allows it to be used as a highly sensitive detection tool for the qualitative and quantitative analysis of trace metal ions in samples. For example, the complex formed by aluminum ions and 8-HQ Alq3 exhibits highly efficient electroluminescence, which is why it is widely used as an electron-transport and emissive material in Organic Light-Emitting Diode (OLED) display technology.
Industrial and Commercial Applications of 8-Hydroxyquinoline
Pharmaceutical Industry
8-Hydroxyquinoline is an important multifunctional intermediate and active ingredient in the pharmaceutical industry. It is widely used in the synthesis of oxyquinoline derivatives with antibacterial, antifungal, and antiviral properties.
Due to its excellent bactericidal and antiseptic properties, 8-HQ is also used directly as an active ingredient or auxiliary ingredient in various topical preparations, such as antibacterial ointments, skin disinfectants, ear drops, and eye drops. In these preparations, it exerts its anti-infective and antiseptic properties, ensuring product safety and efficacy.
Chemical and Analytical Industry
In analytical chemistry, 8-Hydroxyquinoline is an indispensable indicator and chelating precipitant for polyvalent metal ions. It selectively forms stable and brightly colored complexes with a variety of metal ions, including Fe₃+, Zn₂+, Al₃+, and Mg₂+. Therefore, it is widely used in qualitative, gravimetric, and photometric analysis of metal ions. Furthermore, due to its characteristic fluorescence emission upon complexation with specific metals, 8-HQ is also used as a highly sensitive fluorescence detection reagent.
Industrial and Metal Treatment
8-Hydroxyquinoline plays a key role in metal processing and industrial maintenance. It is a highly effective metal rust preventative and corrosion inhibitor. By complexing with metal surface ions, 8-HQ forms a dense, protective complex film on the metal surface, achieving metal passivation and effectively protecting the metal from oxidation and corrosion in acidic and alkaline environments. It is also commonly used as a lubricant additive to enhance its antioxidant and corrosion resistance. It is widely used in electroplating, mechanical manufacturing, and corrosion protection of precision electronic components.
Polymer and Material Stabilization
Due to its inherent antioxidant and chelating properties, 8-Hydroxyquinoline is used as a stabilizer and antioxidant additive in polymeric materials such as plastics, rubber, and synthetic fibers. Adding 8-HQ to polymers effectively captures free radicals and quenches trace metal ions that catalyze degradation, significantly improving the material’s weatherability and heat resistance and extending the product’s lifespan. It is also used to stabilize various industrial liquids and organic coatings, preventing oxidative deterioration during storage and use.
Agriculture and Pesticide Field
In agriculture, 8-Hydroxyquinoline and its derivatives are used as highly effective fungicides and antimicrobials. Their potent chelating and bioactive properties enable them to effectively inhibit the growth of a wide range of fungal and bacterial diseases affecting crops. Besides direct crop protection, 8-HQ is also used to protect industrial products such as wood, leather, and textiles from mold and microbial attack. As an important plant protection chemical, it helps improve the stability of pesticide formulations and provides long-lasting protection for agricultural products.
Safety and Handling of 8-Hydroxyquinoline
8-Hydroxyquinoline should be handled with caution in accordance with standard industrial safety protocols. It is important to avoid contact with strong oxidizing agents, as such substances may cause hazardous reactions. The chemical should be stored in a dry, well-ventilated area, protected from light and moisture to prevent degradation. Recommended storage temperatures range between 15°C and 25°C, with containers kept tightly closed and locked when not in use.
Personal protective equipment (PPE), including gloves, safety goggles, and protective clothing, should be worn to prevent skin and eye contact. Inhalation of dust or vapors should be avoided by working under adequate ventilation or using respiratory protection. Wash your hands thoroughly after handling to prevent ingestion or transfer.
In case of accidental exposure, immediate medical attention is necessary. Eye contact requires rinsing with plenty of water for several minutes, while skin exposure needs washing with soap and water. If swallowed or inhaled, seek emergency medical advice promptly.
Environmentally, 8-hydroxyquinoline is very toxic to aquatic life and should not be released into waterways. Spills should be contained and cleaned up using mechanical means, and disposal must follow approved regulations to minimize environmental impact.
Why Choose Runtai Chemical as Your 8-Hydroxyquinoline（CAS 148-24-3）Supplier
High content and purity
Autech Industry specializes in providing high-quality 8-hydroxyquinoline that meets the most stringent application standards, particularly in pharmaceutical intermediates and OLED material manufacturing, where purity is paramount. Our high-purity products ensure your end products achieve the desired performance and stability.
Stable supply capacity
Autech Industry provides a stable and continuous supply of large quantities, effectively responding to market fluctuations and quickly responding to urgent customer orders. Choosing us can reduce production risks in raw material supply and ensure that your supply chain operates efficiently and stably.
Competitive price advantage
Autech Industry is committed to providing customers with cost-effective products, helping you significantly reduce raw material procurement costs without sacrificing quality, thereby improving the price competitiveness of your end products in the market.
Rich export experience
Autech Industry has many years of international export experience and an understanding of global chemical transportation and trade regulations. Our efficient logistics system ensures safe and fast delivery of products to global customers, providing you with high-quality products and professional services. We are your trusted partner.
Conclusion
8-Hydroxyquinoline（CAS 148-24-3） is a multifunctional compound with extensive applications across diverse industries. Its excellent chelating ability enables it to form stable complexes with metal ions, which is fundamental to its role in pharmaceuticals, analytical chemistry, and industrial processes. Additionally, its strong antioxidant properties protect materials and biological systems from oxidative damage. Its well-documented antimicrobial activity makes it valuable in drug formulations and agricultural fungicides, contributing to infection control and crop protection.
As a reliable supplier, Autech Industry offers high-purity 8-hydroxyquinoline with stringent quality control under ISO and GMP standards. With over 15 years of export experience, Runtai ensures stable supply, customization options, and comprehensive technical support, making it a trusted partner for businesses seeking premium 8-hydroxyquinoline for pharmaceutical, industrial, agricultural, and analytical uses.
