"A practical supplier guide to Resorcinol (CAS 108-46-3, C6H6O2, MW 110.11): a white crystalline phenolic solid with a melting point of 109-112 C, boiling point 281 C, density 1.27, and water solubility of 140 g/100 mL. Covers its dose-dependent skin effects (1-2% antiseptic, 5-20% keratolytic), its role as the building block for resorcinol-formaldehyde resins in tire-cord and wood adhesives, and its use as a dye and pharmaceutical intermediate. Includes handling notes and grade guidance for cosmetic, pharmaceutical, and industrial buyers."
-Deshangchemical-chemechemi
What Resorcinol Is, and Why Buyers Order It for Very Different Reasons
Resorcinol (CAS 108-46-3) is one of those chemicals that turns up in places most buyers never expect. On the same day, a drum of it can leave a plant bound for a cosmetic lab, a tire factory, and a dye house. Formally it is 1,3-dihydroxybenzene, also written as 1,3-benzenediol. With the molecular formula C6H6O2 and a molecular weight of 110.11, it is a small, simple molecule that behaves very differently depending on how much you use and what you put it next to. That flexibility is exactly why it has stayed on the ordering list for decades instead of being replaced by something newer.
The Physical Basics You Spec Against
In its commercial form resorcinol is a white crystalline solid. The technical data we ship against lists a melting point of 109–112 °C, a boiling point around 281 °C, and a density of 1.27. It is freely soluble in water — about 140 g per 100 mL — and also dissolves well in alcohols and ethers. It carries the EINECS number 203-585-2. Because it is a phenol, it should be stored below +30 °C and kept away from strong oxidizers, but its irritation and corrosion profile is milder than phenol itself, which is one reason formulators reach for it when a phenolic effect is wanted without phenol’s bite.
Why Skin-Care Formulators Keep It on the Shelf
Resorcinol has a long history in topical preparations, and its behavior is dose-dependent in a way that matters to a formulator. At 1–2% it acts as an antiseptic, bacteriostatic, and antifungal agent with a mild astringent and anti-itch effect, and it encourages normal keratin regeneration. Move up to 5–20% and it becomes keratolytic — it helps the stratum corneum shed, which is why it appears in treatments for acne, seborrheic dermatitis, and certain scalp conditions. Push to around 40% and the effect turns caustic, which is a concentration handled in industrial or professional settings, not in a consumer jar. Because it can be absorbed through the skin and through ulcerated surfaces, the handling guidance is not boilerplate.
That dose story is also why resorcinol is rarely used alone. In an acne or exfoliating formula it is commonly paired with other well-understood actives. A salicylic acid (CAS 69-72-7) system brings lipid-soluble keratolysis; a glycolic acid (CAS 79-14-1) step adds an alpha-hydroxy exfoliation; and an oil-soluble capryloyl salicylic acid (CAS 78418-01-6) reaches into the sebaceous follicle where water-based acids struggle. For brightening lines, formulators often reach for phenylethyl resorcinol (CAS 85-27-8), a resorcinol-derived tyrosinase inhibitor, or compare it against hydroquinone (CAS 123-31-9) when regulating a whitening claim. If the brief calls for a gentler phenolic in the same family, chlororesorcinol (CAS 95-88-5) and methylresorcinol (CAS 608-25-3) are worth knowing.
The Industrial Half of the Story
Outside the lab, resorcinol’s biggest volume use is as a building block for resorcinol-formaldehyde resins. Like phenol, it condenses with formaldehyde, but the resulting resins stick to things phenolic glues do not — most notably the adhesion between rubber and reinforcing cords. That is the reason resorcinol shows up in tire cord adhesives for nylon and polyester, in industrial rubber bonding, and in weather-resistant wood adhesives for exterior plywood and structural laminates. When a spec sheet talks about rubber-to-metal or vinyl-to-metal joints, resorcinol chemistry is often doing the quiet work, much like benzotriazole (CAS 95-14-7) stabilizes polymers and metals against UV and corrosion in the same supply chain.
It also serves as an intermediate for a wide set of azo and fur dyes and as a raw material for pharmaceutical intermediates. In the photosensitive-film, dye, and chemical-fiber industries it is used both as a reactant and as an analytical reagent. On the crop-protection side, it feeds into intermediates for certain insecticides and herbicides — a different buying conversation from the cosmetic one, but the same drum of C6H6O2.
Handling and Quality Notes for Buyers
A few practical points trip up first-time buyers. Resorcinol is absorbed through the skin and through ulcerated surfaces, so glove and eye protection matter and the workplace-limit conversation should be taken seriously. It is white when fresh and can pick up color on long storage or light exposure, so a low-temperature, dark, sealed store keeps the assay where you want it. We normally supply it in standard polyethylene-lined fibre drums and can document assay, heavy metals, and residue-on-ignition on request.
For teams comparing sources, the things that actually separate one lot from another are consistency of the melting range, low colored-body, and a clean heavy-metals panel — not the headline CAS number, which is identical for everyone. If your application is cosmetic or pharmaceutical, say so up front; the grade and the paperwork differ from the industrial adhesive grade, and mixing them up is an expensive mistake.
Where to Go From Here
Resorcinol is a versatile, well-trodden intermediate, but it is not a one-size ingredient. The right grade, concentration, and co-actives depend entirely on whether you are building a leave-on serum, a tire-cord dip, or a dye bath. If you are scoping a formulation or a resin system and want to talk through grade and packaging options, the product page carries the current specification and lead time, and we are happy to send a sample lot for bench testing before you commit to a full drum.
