Introduction
Bis(2-ethylhexyl) peroxydicarbonate (EHP), CAS 16111-62-9, is the most commercially significant peroxydicarbonate initiator, accounting for the largest share of peroxydicarbonate consumption globally. Its widespread use in PVC suspension polymerization is driven by its favorable combination of reactivity, handling characteristics, and cost-effectiveness.
Key Facts: EHP
- CAS Number: 16111-62-9
- Molecular Formula: C18H34O6
- Molecular Weight: 346.46 g/mol
- Appearance: Colorless to pale yellow liquid
- Active Oxygen: ~4.6% (theoretical)
- 10-Hour Half-Life Temperature: ~43-44 deg C
- SADT: ~5-10 deg C
- Storage: Deep refrigerated, typically -15 to -20 deg C
Synthesis
EHP is produced by the reaction of 2-ethylhexyl chloroformate with hydrogen peroxide under alkaline conditions. Synthesis innovations have focused on improving reaction selectivity, reducing byproduct formation, and enhancing product purity. Modern production employs continuous or semi-continuous processes with precise temperature and pH control to minimize peroxide decomposition during manufacture.
Applications
PVC Polymerization
EHP is the most widely used low-temperature initiator for suspension PVC. Its decomposition in the 40-55 deg C range provides efficient radical generation for PVC grades requiring high K-values. EHP’s liquid form facilitates accurate metering and uniform dispersion in the polymerization reactor.
Copolymer Production
EHP is also employed in the production of vinyl chloride-vinyl acetate copolymers and other specialty vinyl copolymers where low-temperature initiation is advantageous.
Safety
EHP’s very low SADT (~5-10 deg C) necessitates deep refrigerated storage at -15 to -20 deg C. Transport requires specialized refrigerated containers with redundant cooling, temperature monitoring, and alarm systems. All handling must follow strict peroxide safety protocols.
Q: Why is EHP the most widely used peroxydicarbonate?
A: EHP offers the optimal balance of reactivity (T10h ~43 deg C), physical form (low-viscosity liquid for easy handling), solubility in VCM, and cost-effectiveness. Its 2-ethylhexyl substituent provides better solubility and handling characteristics than shorter-chain peroxydicarbonates, while being more economical than many specialty alternatives.
Key Takeaways
- EHP (CAS 16111-62-9) is the dominant peroxydicarbonate initiator for PVC suspension polymerization.
- Its 10-hour half-life of ~43 deg C is ideal for low-to-medium temperature PVC production.
- Deep refrigerated storage (-15 to -20 deg C) is mandatory due to the very low SADT.
- Shandong Do Sender Chemicals supplies high-quality EHP with comprehensive cold chain logistics support.