Physicochemical Properties

4-Methoxystyrene (CAS 637-69-4; MW 134.17 g/mol; molecular formula C₉H₁₀O) is a clear, colorless to pale yellow liquid at room temperature. It possesses a characteristic sweet, floral-aromatic odor attributable to the conjugated vinyl-aryl system combined with the electron-donating methoxy substituent at the para position.

The compound is sparingly soluble in water but fully miscible with common organic solvents including dichloromethane, tetrahydrofuran, ethyl acetate, toluene, and acetone. The electron-donating methoxy group increases the electron density of the vinyl double bond relative to unsubstituted styrene, making 4-methoxystyrene particularly reactive in electrophilic and cationic polymerization processes, as well as in cycloaddition and cross-coupling reactions.

Note: Specific physical constants (boiling point, refractive index, density, flash point) should be verified against the current certificate of analysis (CoA) supplied with each lot. Consult the product specification sheet available from Aladdin Scientific for confirmed lot-specific values.

Laboratory Applications

4-Methoxystyrene serves as a versatile reagent and monomer across several research domains:

• Radical polymerization: Used as a co-monomer or homopolymer precursor in free-radical polymerization to produce poly(4-methoxystyrene) and related copolymers. The methoxy group imparts useful optical and dielectric properties to the resulting materials.
• Cationic and anionic polymerization: The electron-rich vinyl group makes this monomer highly responsive to Lewis acid-initiated cationic polymerization and to organolithium-initiated anionic polymerization, enabling controlled molecular-weight polymers.
• Organic synthesis intermediate: 4-Methoxystyrene participates in Heck cross-coupling reactions, Diels–Alder cycloadditions, hydroboration, epoxidation, and other transformations that exploit the activated double bond.
• Fragrance and flavor chemistry: The compound is a recognized fragrance ingredient; researchers studying aroma compounds may use it as a reference standard or synthetic precursor.
• Material science: Copolymers incorporating 4-methoxystyrene units are investigated for photoresist formulations, liquid-crystal polymer precursors, and functional thin films.

Researchers should optimize inhibitor removal (see Handling section) and reaction conditions for their specific application, as residual stabilizer can suppress initiation in sensitive polymerization systems.

Safe Handling, Storage & Stability

General Precautions: 4-Methoxystyrene is a flammable liquid and should be kept away from open flames, sparks, and other ignition sources. Work in a well-ventilated fume hood. Wear appropriate personal protective equipment (PPE) including chemical-resistant gloves (e.g., nitrile), safety glasses or goggles, and a laboratory coat. Avoid inhalation of vapors and prolonged skin contact.

Inhibitor: Commercial grades of 4-methoxystyrene are typically supplied with a radical polymerization inhibitor (commonly 4-tert-butylcatechol or hydroquinone-type stabilizer) to prevent premature polymerization during storage and transport. Before use in polymerization experiments, the inhibitor must be removed. Standard methods include passage through a column of basic alumina or inhibitor-removal resin, or washing with dilute aqueous NaOH followed by drying. Verify inhibitor identity and concentration on the product CoA.

Storage: Store in a tightly sealed container in a cool, dry, well-ventilated location away from heat, light, and oxidizing agents. Refrigerated storage (2–8 °C) is recommended to maximize shelf life and minimize spontaneous polymerization risk. Containers should be kept under an inert atmosphere (nitrogen or argon) after opening.

Waste Disposal: Dispose of waste material in accordance with local, national, and institutional regulations for flammable organic solvents. Do not pour down the drain. Consult your institution's environmental health and safety office for approved disposal procedures.

Emergency: Refer to the Safety Data Sheet (SDS) provided by Aladdin Scientific for first-aid measures, fire-fighting procedures, and spill-response guidance.

Quality, Purity & Ordering Information

Aladdin Scientific supplies 4-Methoxystyrene under SKU M103131. Researchers should review the product specification sheet and certificate of analysis (CoA) for confirmed purity, inhibitor content, water content, and other quality parameters relevant to their application.

For polymerization-grade use, confirm purity by gas chromatography (GC) and check inhibitor levels prior to use. For synthetic applications, standard reagent-grade material is typically suitable; however, researchers requiring higher purity should contact Aladdin Scientific's technical support team for guidance on available grades.

Bulk quantities, custom packaging, or special purity grades may be available upon request. Contact your regional Aladdin Scientific representative or submit an inquiry through the official website for pricing, lead times, and regulatory documentation (SDS, CoA, export compliance).