Hydroquinone

　　Core Application Areas

　　1. Polymer Industry: High-efficiency Polymerization Inhibitor

　　Inhibits the free-radical polymerization of monomers (styrene, acrylic acid, vinyl acetate, etc.) and extends shelf life (addition amount 0.01%-0.1%);

　　Principle: Captures free radicals generated during the polymerization reaction (such as •OH, R•) and terminates chain growth.

　　2. Photography and Imaging Technology

　　Black and white film developer: Reacts with silver ions (Ag⁺) to reduce exposed silver halide to metallic silver (core of the image), often used in combination with Metol (p-methylaminophenol);

　　Color film bleach: Participates in image stabilization processing.

　　3. Pharmaceuticals and Cosmetics

　　Skin whitening agent: Inhibits tyrosinase activity and reduces melanin production (2%-4% concentration used in spot-removal creams), but the EU (EC) restricts its use due to potential cytotoxicity, while China stipulates a concentration of ≤0.02% for leave-on cosmetics;

　　Topical medication: 5% ointment used to treat psoriasis, effective by inhibiting epidermal cell proliferation.

　　4. Dyes and Fine Chemicals

　　Intermediate for the synthesis of azo dyes (e.g., Direct Sun Blue) and anthraquinone dyes;

　　Preparation of antioxidants (e.g., tert-butylhydroquinone, TBHQ) and rubber anti-aging agents;

　　Used as electroplating brightener: Improves the uniformity and gloss of nickel and copper coatings.

　　5. Energy and Environmental Protection

　　Battery additive: Inhibits corrosion of the negative plate and hydrogen evolution in lead-acid batteries, extending service life;

　　Wastewater treatment: Reduces heavy metal ions in water (e.g., Cr⁶⁺→Cr³⁺), lowering toxicity.