Naphthalene

Updated: 2026-08-29

Overview

Industrial naphthalene is a primary aromatic hydrocarbon obtained from coal tar distillation or petroleum refining. As one of the simplest polycyclic aromatic hydrocarbons (PAHs), it serves as a foundational raw material for synthesizing derivatives like phthalic anhydride, which is essential for plasticizers and polyester resins. Its historical use as a moth repellent has declined due to toxicity concerns, but it remains vital in industrial applications, particularly in Asia where coal tar production is prevalent. The global market is driven by demand from the construction and textile industries.

Physical and Chemical Properties

Naphthalene crystallizes into white flakes with a characteristic pungent odor. It sublimes readily at room temperature, transitioning directly from solid to vapor, which aids in purification processes. The compound is highly hydrophobic, limiting its environmental persistence in aquatic systems. Chemically, it undergoes electrophilic substitution reactions, enabling the production of sulfonated or halogenated derivatives. Its flammability (autoignition at 526°C) and moderate toxicity necessitate careful handling. The vapor pressure of 0.08 mmHg at 25°C indicates significant volatility.

Main Applications

Over 60% of industrial naphthalene is converted to phthalic anhydride, a precursor for PVC plasticizers and unsaturated polyester resins. In agrochemicals, it synthesizes carbaryl insecticides. The textile industry uses sulfonated naphthalene as a dispersant in dyeing processes. Niche applications include carbon black production and as a binder in refractory bricks. Recycled naphthalene from local recovery programs (as queried) often meets lower-grade requirements for construction materials, reducing reliance on virgin feedstock.

Safety and Storage

Classified as a flammable solid (UN 1334/PG III), naphthalene requires storage in airtight containers to prevent sublimation and moisture absorption. Facilities must adhere to NFPA 30 guidelines, with grounding to avoid static ignition. Workers should use PPE (gloves, respirators) to limit exposure. Spills should be contained using inert absorbents like vermiculite. Environmental releases are hazardous to aquatic life; reporting thresholds apply under EPA regulations. Long-term storage may form peroxides; periodic inspection is recommended.

B2B Procurement Guide

Buyers should prioritize suppliers with ISO 9001 certification and batch-specific COAs (Certificates of Analysis) detailing purity, moisture content, and ash residue. Bulk shipments typically use 25-kg woven bags or 1-ton super sacks, while smaller quantities come in steel drums. Regional pricing fluctuates with coal tar availability; Southeast Asian markets often offer competitive rates. For recycled naphthalene, verify contaminant levels (e.g., sulfur compounds) that may affect downstream processes. Incoterms should clearly define liability for transportation hazards.