Antioxidants
REACH
4-methoxyphenol
CAS Number
150-76-5
EC Number
205-769-8
What is 4-methoxyphenol?
4-Methoxyphenol (CAS 150-76-5), also known commercially as mequinol and 4-hydroxyanisole, functions as a polymerization inhibitor and antioxidant in industrial chemical processing.
Where is 4-methoxyphenol used?
- Plastics and polymer manufacturing: stabilizes vinyl and acrylic monomers against unwanted polymerization during bulk storage
- Coatings and adhesives: extends shelf life
- UV-curable and reactive resin systems: prevents premature gelation
- Pharmaceutical intermediate: topical depigmentation active and building block for API synthesis
- Personal care: incorporated into skin-lightening products
- It prevents premature crosslinking and radical chain reactions in reactive monomer systems.
Good to know: Technical grade is standard for industrial inhibitor applications, while pharmaceutical and cosmetic buyers typically source material meeting BP or USP specifications. Regulatory-grade purity is a procurement requirement for these applications.
Commercial specifications
- Packaging ranges from kilogram-scale bags to bulk drum quantities
Other Names (Synonyms)
4-hydroxyanisole|1-Hydroxy-4-methoxybenzene|Mequinol|p-hydroxyanisole|p-Guaiacol|Leucodine B|Leucobasal®
What are the physical properties of 4-methoxyphenol?
Melting Point 57 °C
Boiling Point 243 °C @ Press: 760 Torr
Density 1.55 g/cm³ @ Temp: 20 °C
Flash Point >230 °F
Appearance 4-Methoxyphenol is a colorless to white, waxy solid with an odor of caramel and phenol. A combustible solid.
Color Clear colorless to pale yellow
Odor Phenolic
Form Liquid
Water Solubility 40 g/L (25 ºC)
Vapor Pressure <0.01 mm Hg ( 20 °C)
Refractive Index 1.5286 (estimate)
pH 5.1 (30g/l, H2O, 20℃)
Log P 1.3 at 20℃
How is 4-methoxyphenol classified and handled safely? Learn More
Warning
GHS07· Irritant GHS08· Health Hazard
Hazard Statements
H302 Harmful if swallowed [Warning Acute toxicity, oral]
H317 May cause an allergic skin reaction [Warning Sensitization, Skin]
H319 Causes serious eye irritation [Warning Serious eye damage/eye irritation]
H320 Causes eye irritation [Warning Serious eye damage/eye irritation]
Which trade and regulatory codes apply to 4-methoxyphenol?
HS Code 29095090
Storage Class 11 - Combustible Solids
WGK (Germany) 1