Salicylic Acid: Complete Material Overview

What Is Salicylic Acid?

Salicylic acid stands out as a widely recognized chemical compound in both industrial and daily-use products. With a molecular formula of C₇H₆O₃, it takes form as a white, odorless crystalline solid at room temperature. The molecular structure features a carboxylic acid group attached to a benzene ring that also carries a hydroxyl group, giving rise to its unique properties. This compound appears regularly in pharmaceutical formulas, skincare solutions, agrochemicals, and synthetic applications. Manufacturers rely on chemical properties such as its melting point of about 159°C, its slight solubility in water, and its easy solubility in alcohol and ether. Salicylic acid falls under HS Code 291821, which fits within the broader family of aromatic carboxylic acids and their derivatives. Each attribute – from its density to its acid dissociation constant – fits specific needs for industries ranging from medicine to cosmetics.

Products and Raw Material Applications

Factories and research labs seek out salicylic acid both as a finished product and a critical raw material. In its pure form, the compound shows up as flakes, powder, or crystalline pearls. Some producers offer it dissolved in alcohol or water to suit different processing needs. The raw material feeds into aspirin synthesis, a process that requires strict quality control around purity and melting characteristics. Salicylic acid goes directly into topical treatments where its ability to break down keratin makes it a front-line tool in acne and psoriasis products. Textile producers use it to create dyes that bind solidly to fabrics, while agrochemical firms depend on its fungicidal properties. Beyond large-scale production, laboratories stock it for analytical routines and organic synthesis.

Physical Structure, Density, and Solution Information

Solid salicylic acid presents as white, needle-like crystals or a soft, chalky powder. It holds a specific gravity of 1.44 g/cm³ at 20°C and remains stable under normal storage conditions. Its slight bitterness stands out upon taste, though such information stays mostly relevant for analytical identification. Solubility gets a lot of focus: the compound dissolves poorly in cold water, yielding only about 2g per liter at 20°C, but dissolves freely in ethanol, ether, and acetone. Liquid formulations mix salicylic acid into various solutions depending on the application; these solutions allow controlled dosing in clinical or industrial uses. The transition from flake to solution, or powder to paste, changes application range, which is a major consideration for anyone choosing supply formats.

Chemical Properties and Safety Concerns

Salicylic acid shows moderate acidity, with a pKa around 2.97. This level lets it function both as a preservative and an exfoliant across product categories. The substance reacts readily with acylating and alkylating agents, and its behavior in esterification forms the backbone of aspirin production. As with most benzoic acid derivatives, salicylic acid releases toxic smoke if heated to decomposition. Handling requires goggles, gloves, and protective clothing to avoid skin and eye irritation. Prolonged inhalation or ingestion proves harmful, leading to possible respiratory distress or stomach discomfort. It does not qualify as a carcinogen, but workers and users should always heed exposure limits and proper ventilation during processing. Disposal of leftover material follows standard hazardous chemical procedures to prevent water or soil contamination.

Specifications, Purity, and Storage

Producers supply salicylic acid in a range of purities. Pharmaceutical and cosmetic grades demand over 99% purity, while industrial grades tolerate minor impurities for certain applications. Suppliers disclose the level of heavy metals, ash, and organic byproducts to address regulatory and manufacturing requirements. Finished containers take the form of sealed fiber drums or thick polyethylene bags, each lined to resist moisture and cross-contamination. Material should remain in a cool, dry warehouse away from strong oxidizers or acids. Spilled powder may pose dust hazards and should be swept up with care and contained for proper disposal or recycling.

Real-World Experience and Responsible Use

In my work with laboratory supply and chemical sourcing, getting the right batch of salicylic acid has always needed a good eye for details. Physical state, color, and even the ‘feel’ of the powder make a difference in downstream processing. Mistakes around improper storage or casual handling have led to spills and minor skin irritations. Strong odorless crystals might seem harmless, yet unguarded exposure over hours in a cramped lab will irritate the nose and skin. Relying on credible distributors, reviewing batch certificates, and using fume hoods during weighing and mixing stops small oversights from becoming workplace hazards. In manufacturing, on-site safety audits often recommend easy-to-read storage labels, clear spill protocols, and regular refresher training for anyone who handles bulk quantities. Such basic steps do more to protect workers and downstream consumers than any fancy automation or new equipment.

Solutions for Safe and Sustainable Handling

Companies that use salicylic acid in large volumes focus on safer processes and greener sourcing. Switching from open powder handling to closed transfer systems limits dust and accidental inhalation. Adopting improved ventilation keeps airborne concentrations far below occupational safety thresholds. As supply chains tighten their requirements, more firms choose material with full traceability and sustainability certifications. Recycling unused or expired product through reclamation programs helps cut down on hazardous waste. Training remains an ongoing priority, not just for the safety team, but for everyone working on the production line, in the warehouse, or at transport docks. Documentation at every step – from receiving and storage through formulation and disposal – stays key for meeting both legal and ethical standards.

Summary of Key Property Data

Molecular formula: C₇H₆O₃
CAS Number: 69-72-7
HS Code: 291821
Appearance: White flakes, powder, or crystalline pearls
Melting point: 158-161°C
Boiling point: 211°C (decomposes)
Density: 1.44 g/cm³ at 20°C
Solubility: Poor in water, strong in alcohol, ether, acetone
pKa: 2.97
Class: Aromatic carboxylic acid
Toxicity: Harmful if swallowed, inhaled, or upon skin contact