Introduction
Tert-Butyl peroxy-2-ethylhexanoate (CAS 686-31-7) is a peroxyester initiator with the same chemical identity as CAS 3006-82-4, registered under a different CAS number that may appear in certain regulatory or commercial documents. The 2-ethylhexanoate ester group provides excellent solubility in vinyl monomers and organic solvents, while the tert-butyl peroxy moiety delivers predictable decomposition kinetics suitable for medium-temperature polymerization processes.
Key Facts
- CAS Number: 686-31-7 (alternative to CAS 3006-82-4)
- Molecular Formula: C12H24O3
- Molecular Weight: 216.32 g/mol
- Appearance: Colorless to pale yellow liquid
- 10-Hour Half-Life Temperature: ~73 deg C
- 1-Hour Half-Life Temperature: ~92 deg C
- SADT: ~45 deg C
- Storage: Refrigerated, typically below 10 deg C
Physical Properties
| Property | Value |
|---|---|
| Appearance | Colorless to pale yellow liquid |
| Density (20 deg C) | ~0.90 g/cm3 |
| Active Oxygen | ~7.4% (theoretical) |
| Viscosity | ~3 mPa.s |
| Solubility in Monomers | Excellent in styrene, MMA, VCM, acrylates |
| SADT | ~45 deg C |
Applications
PVC Suspension Polymerization
TBPEH is a critical initiator for suspension PVC production. Its decomposition in the 55-65 deg C range provides consistent radical generation throughout the polymerization cycle, contributing to uniform particle morphology, controlled K-value, and low residual monomer levels.
Polystyrene Production
In GPPS and HIPS manufacturing, TBPEH serves as a medium-temperature initiator in continuous mass polymerization processes, supporting steady-state operation and consistent product quality.
Acrylic Polymerization
TBPEH effectively initiates the polymerization of MMA and other acrylic monomers in bulk and solution processes, with minimal impact on polymer color and optical clarity.
LDPE Production
In high-pressure LDPE processes, TBPEH can function as an initiator in specific temperature zones of the reactor system.
Safety and Storage
TBPEH requires refrigerated storage below 10 deg C. Key safety measures include:
- Continuous temperature monitoring with alarm systems
- Explosion-proof electrical equipment in storage and handling areas
- Avoidance of contamination with acids, bases, and accelerators
- Adequate ventilation and secondary containment
- FIFO inventory management
Frequently Asked Questions
Q: Why are there two CAS numbers (686-31-7 and 3006-82-4) for what appears to be the same compound?
A: In some cases, different CAS numbers may be assigned to the same chemical substance due to historical registration practices or different stereochemical/isomeric specifications. For TBPEH, CAS 3006-82-4 is the more commonly cited number. When sourcing or specifying this material, it is advisable to confirm the identity using multiple identifiers (CAS number, IUPAC name, molecular formula) to ensure consistency between supplier documentation and your quality specifications.
Q: What is the primary advantage of TBPEH for PVC production?
A: TBPEH offers an optimal combination of: (1) appropriate half-life temperature for the PVC suspension polymerization temperature window (55-65 deg C), (2) excellent solubility in VCM providing uniform initiator distribution, (3) predictable first-order decomposition kinetics, (4) decomposition products that do not adversely affect PVC resin quality, and (5) competitive cost structure. These factors make it one of the most widely used peroxyesters in the global PVC industry.
Key Takeaways
- TBPEH (CAS 686-31-7/3006-82-4) is a workhorse peroxyester initiator for the PVC industry.
- Its 10-hour half-life of ~73 deg C provides effective initiation in the 55-80 deg C range.
- Applications span PVC, polystyrene, acrylic polymers, and LDPE production.
- Refrigerated storage is required due to the SADT of ~45 deg C.
- Shandong Do Sender Chemicals is a reliable supplier of high-quality TBPEH for global polymerization markets.