Divinylbenzene

Product Details

CasNo： 1321-74-0

MF： C10H10

Appearance： liquid

Delivery Time： 15 days

Packing： 200kg/drum

Purity： 99%

1. Basic Information

2. Physical Properties

• Appearance: Colorless to pale yellow transparent liquid (darkens gradually when exposed to light or air due to polymerization).
• Odor: Characteristic aromatic odor (similar to styrene, but more pungent).
• Boiling Point: ~195-205°C (varies slightly by isomer content; decomposes slightly at atmospheric pressure).
• Melting Point: ~-87°C (mixed isomers).
• Density: 0.911-0.917 g/cm³ (20°C).
• Refractive Index: 1.562-1.568 (n₂₀/D).
• Solubility: Insoluble in water; miscible with organic solvents such as benzene, toluene, xylene, styrene, ethyl acetate, and chloroform.
• Viscosity: ~1.0-1.2 mPa·s (25°C), low viscosity for easy mixing with monomers.

3. Chemical Properties

The core reactivity of DVB comes from its two vinyl functional groups, which undergo rapid polymerization under specific conditions:

• Polymerization Activity: Easily undergoes free radical polymerization (triggered by initiators like benzoyl peroxide, AIBN) or cationic polymerization. The dual vinyl groups act as crosslinkers—each group can react with other monomers (e.g., styrene, acrylonitrile) to form a crosslinked polymer network.
• Oxidation Sensitivity: Reacts with oxygen in air to form peroxides, which may accelerate self-polymerization. Therefore, commercial DVB usually contains inhibitors (e.g., tert-butylcatechol, TBC, ~50-200 ppm) to prevent premature polymerization during storage.
• Stability: Unstable at high temperatures (>200°C) or under UV light—may undergo self-polymerization, leading to gelation or solidification.
• Aromatic Ring Reactions: The benzene ring can undergo substitution reactions (e.g., sulfonation, chlorination) after polymerization, enabling functional modification of polymer products.

4. Production Method

Industrial DVB is mainly produced as a byproduct of ethylbenzene dehydrogenation (a process used to manufacture styrene):

1. Raw Material Source: During ethylbenzene dehydrogenation to styrene, a small fraction of ethylbenzene is further dehydrogenated to form ethylvinylbenzene (EVB).
2. Secondary Dehydrogenation: EVB is separated from the styrene mixture via distillation, then subjected to secondary catalytic dehydrogenation (using catalysts like iron oxide or chromium oxide) to convert the ethyl group (−C2​H5​) to a second vinyl group (−CH=CH2​), forming DVB.
3. Purification: The crude DVB is purified by vacuum distillation to remove unreacted EVB and heavy impurities, then stabilized with inhibitors before packaging.

5. Key Applications

DVB’s primary value lies in its role as a crosslinking agent for polymers, with applications spanning multiple industries:

5.1 Polymer Synthesis (Core Application)

• Ion Exchange Resins: The most important application. DVB is copolymerized with styrene to form a crosslinked polystyrene matrix. This matrix is then sulfonated (to make cation exchange resins) or aminated (to make anion exchange resins), which are widely used in water treatment (softening, desalination), pharmaceutical purification, and chemical separation.
• Plastic and Rubber Modification:
  • Added to polystyrene (PS) or high-impact polystyrene (HIPS) to improve heat resistance and dimensional stability.
  • Used in butadiene-styrene rubber (SBR) or nitrile rubber (NBR) as a crosslinker to enhance tensile strength and wear resistance.
• Microspheres and Adsorbents: Copolymerized with monomers like methyl methacrylate (MMA) to produce uniform crosslinked polymer microspheres, used in chromatography columns, drug delivery systems, and cosmetic additives.

5.2 Specialty Materials

• Composite Materials: Used as a crosslinking component in unsaturated polyester resins (UPR) or epoxy resins to improve the rigidity and chemical corrosion resistance of composites (e.g., fiberglass-reinforced plastics for automotive or marine parts).
• Electronics: Crosslinked polymers derived from DVB have good insulation and heat resistance, making them suitable for encapsulating electronic components or as dielectric materials.
• Laboratory Reagents: Used to synthesize solid-phase extraction (SPE) sorbents or polymer-supported catalysts (e.g., for organic synthesis reactions).

6. Safety, Packaging, and Storage

6.1 Safety Precautions

• Toxicity: Low acute toxicity (oral LD₅₀ in rats: ~3000 mg/kg), but irritates the skin, eyes, and respiratory tract. Prolonged contact may cause dermatitis; inhalation of vapor can lead to dizziness or throat irritation.
• Fire Hazard: Flammable liquid (flash point: ~74°C, closed cup); vapor-air mixtures are explosive (explosion limit: ~0.7-6.0% by volume). Avoid contact with open flames, high temperatures, or strong oxidizers.
• Polymerization Risk: Without inhibitors, DVB can polymerize violently under heat or UV light, releasing heat and causing container rupture. Do not mix with strong acids, bases, or free radical initiators unless under controlled process conditions.

6.2 Packaging

• Typically packaged in dark brown glass bottles (for small quantities, 100-500 mL) or sealed HDPE plastic drums (for industrial quantities, 20-200 L). Dark containers prevent light-induced polymerization.

6.3 Storage

• Store in a cool, dry, well-ventilated warehouse (temperature: 5-30°C), away from direct sunlight, heat sources, and oxidizers.
• Keep containers tightly sealed to avoid evaporation of DVB and absorption of oxygen (which forms peroxides).
• Shelf life: ~6-12 months under proper storage (check for signs of cloudiness or viscosity increase before use, which indicate partial polymerization).

7. Market and Quality Standards

• Purity Grades: Commercial DVB is graded by divinylbenzene content:
  • Standard grade: DVB content ≥ 50% (remaining: EVB and impurities).
  • High-purity grade: DVB content ≥ 80% (used for high-performance resins, e.g., ion exchange resins for pharmaceutical use).
• Key Quality Indicators: DVB isomer ratio, EVB content, inhibitor concentration, and peroxide value (to ensure stability).
• Regulatory Compliance: Complies with standards such as ASTM D2191 (for DVB in polymer applications) or REACH (EU) for chemical safety.