Salicylic acid is a type of beta hydroxy acid that can be found naturally in nature or manufactured synthetically and used in skin treatment products. If you have ever had issues with acne, blackheads, whiteheads, or enlarged pores, then you are likely familiar with salicylic acid (SA). Even if you have not heard of it, you have probably used it, as it is the go-to solution for these types of skin problems, together with benzoyl peroxide. SA is an ingredient that is soluble in lipids, which means it can penetrate the pores of those who have oily or acne-prone skin, particularly those with “open comedones,” better known as blackheads. This makes it especially effective since it helps to keep the pores free of any substances that can cause acne.

Salicylic Acid (Wikipedia)

Salicylic acid is an organic compound with the formula HOC₆H₄CO₂H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Substances Control Act (TSCA) Chemical Substance Inventory as an experimental teratogen. The name is from Latin salix for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates.

Salicylic acid

Names
Preferred IUPAC name 2-Hydroxybenzoic acid
Identifiers
CAS Number	69-72-7 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16914 Y
ChEMBL	ChEMBL424 Y
ChemSpider	331 Y
DrugBank	DB00936
ECHA InfoCard	100.000.648
EC Number	200-712-3
IUPHAR/BPS	4306
KEGG	D00097 Y
PubChem CID	338
RTECS number	VO0525000
UNII	O414PZ4LPZ Y
CompTox Dashboard (EPA)	DTXSID7026368
InChI InChI=1S/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10) Y Key: YGSDEFSMJLZEOE-UHFFFAOYSA-N Y InChI=1/C7H6O3/c8-6-4-2-1-3-5(6)7(9)10/h1-4,8H,(H,9,10) Key: YGSDEFSMJLZEOE-UHFFFAOYAQ
SMILES O=C(O)c1ccccc1O
Properties
Chemical formula	C7H6O3
Molar mass	138.122 g/mol
Appearance	Colorless to white crystals
Odor	Odorless
Density	1.443 g/cm3 (20 °C)
Melting point	158.6 °C (317.5 °F; 431.8 K)
Boiling point	200 °C (392 °F; 473 K) decomposes 211 °C (412 °F; 484 K) at 20 mmHg
Sublimation conditions	Sublimes at 76 °C
Solubility in water	1.24 g/L (0 °C) 2.48 g/L (25 °C) 4.14 g/L (40 °C) 17.41 g/L (75 °C) 77.79 g/L (100 °C)
Solubility	Soluble in ether, CCl4, benzene, propanol, acetone, ethanol, oil of turpentine, toluene
Solubility in benzene	0.46 g/100 g (11.7 °C) 0.775 g/100 g (25 °C) 0.991 g/100 g (30.5 °C) 2.38 g/100 g (49.4 °C) 4.4 g/100 g (64.2 °C)
Solubility in chloroform	2.22 g/100 mL (25 °C) 2.31 g/100 mL (30.5 °C)
Solubility in methanol	40.67 g/100 g (−3 °C) 62.48 g/100 g (21 °C)
Solubility in olive oil	2.43 g/100 g (23 °C)
Solubility in acetone	39.6 g/100 g (23 °C)
log P	2.26
Vapor pressure	10.93 mPa
Acidity (pKa)	2.97 (25 °C) 13.82 (20 °C)
UV-vis (λmax)	210 nm, 234 nm, 303 nm (4 mg/dL in ethanol)
Magnetic susceptibility (χ)	−72.23·10−6 cm3/mol
Refractive index (nD)	1.565 (20 °C)
Dipole moment	2.65 D
Thermochemistry
Std enthalpy of formation (ΔfH⦵298)	−589.9 kJ/mol
Std enthalpy of combustion (ΔcH⦵298)	3.025 MJ/mol
Pharmacology
ATC code	A01AD05 (WHO) B01AC06 (WHO) D01AE12 (WHO) N02BA01 (WHO) S01BC08 (WHO)
Hazards
Occupational safety and health (OHS/OSH):
Eye hazards	Severe irritation
Skin hazards	Mild irritation
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H318
Precautionary statements	P280, P305+P351+P338
NFPA 704 (fire diamond)	2 1 0
Flash point	157 °C (315 °F; 430 K) closed cup
Autoignition temperature	540 °C (1,004 °F; 813 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	480 mg/kg (mice, oral)
Safety data sheet (SDS)	MSDS
Related compounds
Related compounds	Methyl salicylate, Benzoic acid, Phenol, Aspirin, 4-Hydroxybenzoic acid, Magnesium salicylate, Choline salicylate, Bismuth subsalicylate, Sulfosalicylic acid, Salicylate synthase
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references