Introduction

Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound and a type of phenol derived from benzene. With the chemical formula C₆H₄(OH)₂ and CAS No. 123-31-9, Hydroquinone is widely used as a water-soluble reducing agent in photographic processing, polymerization inhibition, chemical synthesis, water treatment, oilfield operations, paints, dyes, pigments, and selected pharmaceutical and cosmetic formulations.

Its strong reducing properties and antioxidant behavior make Hydroquinone particularly useful in applications where oxidation or free-radical polymerization needs to be controlled. At the same time, its tendency to oxidize and discolor when exposed to air and light needs to be considered during storage and handling.

What Is Hydroquinone?

Hydroquinone is an aromatic organic compound belonging to the phenol family. It contains two hydroxyl groups attached to a benzene ring at the para position, giving it the chemical name benzene-1,4-diol. Its molecular formula is C₆H₄(OH)₂, and its CAS No. is 123-31-9. Under normal conditions, it is supplied as a white crystalline powder.

Hydroquinone has a melting point of 172–175°C and a boiling point of 285–286°C. It is highly soluble in water, ethanol, and ether, while being slightly soluble in benzene. The compound possesses strong reducing properties and is prone to oxidation and discoloration when exposed to air and light, forming p-benzoquinone.

These chemical characteristics determine many of its industrial applications, particularly its use as a reducing agent, antioxidant, and free-radical scavenger.

Key Properties of Hydroquinone

Hydroquinone is mainly valued for its reducing properties, antioxidant behavior, solubility, and ability to control free-radical reactions. For reference, the key product information is summarized below.

Product Basic Information – Hydroquinone

Main Applications of Hydroquinone

1. Photographic Developer

Hydroquinone is an important component in many black-and-white photographic developers used for film and photographic paper. In combination with Metol, Hydroquinone acts as a reducing agent that converts silver halides into elemental silver, allowing the photographic image to develop.

Sodium sulfite is typically added to photographic developer formulations to help prevent autooxidation of the developer. The reducing properties of Hydroquinone therefore play a direct role in the chemical development process and image formation.

2. Polymerization Inhibitor

Hydroquinone is widely used as a polymerization inhibitor because of its antioxidant properties and ability to act as a free-radical scavenger. It is used to prevent unwanted polymerization of acrylic acid, methyl methacrylate, cyanoacrylate, and other monomers that are susceptible to radical-initiated polymerization.

By controlling free-radical reactions, Hydroquinone helps prolong the shelf life of light-sensitive resins and other monomer-containing materials, including preceramic polymers. According to the supplied material, polymerization inhibition represents the largest industrial application of Hydroquinone, accounting for roughly two-thirds of global consumption.

3. Chemical Intermediate

Hydroquinone can also be used as a chemical intermediate in polymer and specialty chemical production. Both hydroxyl groups can lose a hydrogen cation to form a diphenolate ion, allowing Hydroquinone to participate in further chemical reactions.

The disodium diphenolate salt of Hydroquinone is used as an alternating comonomer unit in the production of PEEK (polyether ether ketone). This application demonstrates the role of Hydroquinone as a functional intermediate in the preparation of advanced polymer materials.

4. Water Treatment, Oilfield, Paints, Dyes, and Other Applications

Hydroquinone is also used in several other industrial and specialty applications because of its reducing and antioxidant properties. It can function as an oxygen scavenger in water treatment and oilfield operations, where its reducing properties are utilized to control dissolved oxygen.

In the coatings industry, Hydroquinone can be used as an anti-skinning agent in paints, helping prevent unwanted skin formation during storage. It is also used as an intermediate in the production of dyes and pigments.

Hydroquinone is additionally used as a skin-lightening agent in pharmaceutical and cosmetic formulations; however, its cosmetic use is restricted or banned in several countries because of safety concerns.

Supply Considerations for Hydroquinone

For buyers sourcing Hydroquinone, product quality, packaging, storage conditions, and transportation classification are important considerations. Hydroquinone is prone to oxidation and discoloration when exposed to air and light, so appropriate packaging and storage conditions help maintain its original appearance and product stability.

According to the supplied product information, FAIRSKY's Hydroquinone is normally supplied at 99% minimum content and packed in 25 kg paper-plastic composite bags. The product is classified as UN3077, Hazard Class 9, Packing Group III, which should be taken into account when arranging international transportation and logistics.

For industrial users, stable product specifications and appropriate packaging are particularly important when Hydroquinone is used as a polymerization inhibitor, photographic developer, or chemical intermediate, because variations in material characteristics can influence downstream processing and storage performance.

Fairsky: Hydroquinone Manufacturing and Supply

FAIRSKY supplies Hydroquinone (C₆H₄(OH)₂, CAS 123-31-9) for customers using the material in photographic processing, polymerization inhibition, chemical synthesis, water treatment, oilfield operations, paints, dyes, pigments, and other industrial applications.

The typical Hydroquinone specification supplied by FAIRSKY is 99% min, with standard packing of 25 kg paper-plastic composite bags. As Hydroquinone is classified as UN3077, Hazard Class 9, Packing Group III, appropriate transportation and packaging arrangements are considered when supplying the product to international customers.

FAIRSKY provides product information and export coordination for customers sourcing Hydroquinone from China, supporting different industrial requirements with stable specifications and suitable packing options.

Conclusion

Hydroquinone is an important aromatic organic compound whose strong reducing and antioxidant properties support a wide range of industrial applications. It is used as a photographic developer, polymerization inhibitor, chemical intermediate, oxygen scavenger, anti-skinning agent, and dye and pigment intermediate, with polymerization inhibition representing its largest industrial application according to the supplied material.

For buyers, understanding the product's chemical properties, storage sensitivity, packaging requirements, and transportation classification is important when sourcing Hydroquinone. FAIRSKY supplies Hydroquinone with 99% min specification and 25 kg paper-plastic composite bag packing for customers worldwide.