Introduction
Bis(3,5,5-trimethylhexanoyl) peroxide, also known as diisononanoyl peroxide, is a diacyl peroxide featuring branched C9 acyl groups. This compound serves as a polymerization initiator and crosslinking agent, with its branched alkyl structure providing distinctive solubility and decomposition characteristics.
Key Facts
- CAS Number: 3851-87-4
- Molecular Formula: C18H34O4
- Molecular Weight: 314.47 g/mol
- Appearance: Colorless to pale yellow liquid
- Active Oxygen: ~5.1% (theoretical)
- 10-Hour Half-Life Temperature: ~62 deg C
- SADT: ~35-40 deg C
Physical Properties
| Property | Value |
|---|---|
| Appearance | Colorless to pale yellow liquid |
| Density | ~0.9 g/cm3 |
| Active Oxygen | ~5.1% |
| Solubility in Water | Insoluble |
| Solubility in Organics | Soluble in hydrocarbons, esters, ketones |
| SADT | ~35-40 deg C |
Applications
Polyethylene Production
This peroxide serves as an initiator for the high-pressure polymerization of ethylene to LDPE. Its decomposition kinetics in the 150-250 deg C range provide controlled radical generation in tubular and autoclave reactor processes.
Rubber and Elastomer Crosslinking
Bis(3,5,5-trimethylhexanoyl) peroxide can function as a crosslinking agent for certain elastomer systems, though it is less commonly used for this purpose compared to dialkyl peroxides such as DCP and BIPB.
Acrylic Polymerization
It is also employed as an initiator for acrylic and methacrylic monomer polymerization in bulk, solution, and suspension processes.
Safety
With a SADT of ~35-40 deg C, this peroxide requires temperature-controlled storage below 25 deg C but does not typically require deep refrigeration. Standard organic peroxide handling protocols apply.
Frequently Asked Questions
Q: How does the branched structure affect peroxide performance?
A: The 3,5,5-trimethylhexanoyl group’s branched structure influences solubility in monomers and polymers, decomposition kinetics, and the reactivity of the resulting acyloxy and alkyl radicals. Branched acyl peroxides typically exhibit slightly different decomposition rate constants compared to their linear analogs, and the resulting radicals may show modified reactivity due to steric effects.
Key Takeaways
- Bis(3,5,5-trimethylhexanoyl) peroxide (CAS 3851-87-4) is a branched diacyl peroxide initiator.
- Applications include LDPE production, elastomer crosslinking, and acrylic polymerization.
- Moderate thermal stability means refrigerated storage is recommended but deep-freeze is not required.
- Shandong Do Sender Chemicals supplies this initiator for various polymerization applications.