Introduction
In the high-stakes world of polymermanufacturing, where precise control over reaction kinetics determines product
quality and process efficiency, initiator selection is critical. tert-Butyl peroxypivalate (CAS 927-07-1) standsout as a cornerstone organic peroxide specifically engineered for demanding
polymerization processes requiring low-temperature initiation. This
comprehensive guide delves into the chemistry, industrial applications, vital
safety protocols, and sourcing strategies surrounding this indispensable
chemical. Understanding tert-Butyl peroxypivalate (927-07-1) empowerschemists, engineers, and procurement specialists to optimize PVC production,
enhance polymer properties, and ensure operational safety.
What is tert-Butyl Peroxypivalate (CAS 927-07-1)?
tert-Butyl peroxypivalate, uniquely identified by CAS registry number 927-07-1, is ahighly efficient, low-temperature organic peroxide initiator. Its molecular
structure features a tert-butyloxy group ((CH₃)₃C-O-) linked viaa peroxide bond (-O-O-) to a pivaloyl group ((CH₃)₃C-C(=O)-),forming an ester linkage and yielding the molecular formula C₉H₁₈O₃. This specificarrangement dictates its decomposition behavior and radical generation profile.
Distinguishing Key Properties and Structure
Chemical Names:tert-Butyl peroxypivalate, tert-Butyl peroxy-2,2-dimethylpropanoate (IUPAC),
tert-Butyl perpivalate (Note: This name often causes confusion with the
similar-sounding but distinct CAS 29240-17-3 compound. CAS 927-07-1 is the
subject of this article), Perkadox BP (common brand name).
CAS Number: 927-07-1(Critical Unique Identifier).
Molecular Formula: C₉H₁₈O₃
Molecular Weight: 174.24g/mol
Physical State: Clear, colorless to slightly yellow liquid.
Odor: Characteristic pungent, sharp odor.
Solubility: Freely soluble in most organic solvents (aliphatic, aromatichydrocarbons, esters, ethers, ketones). Insoluble in water.
Critical Decomposition Temperatures (T₁/₂): This is its defining characteristic.
T₁/₂ (10h) ≈ 44-46°C
T₁/₂ (1h) ≈ 55-57°C
(Always refer to current supplierdatasheets for precise, batch-specific values)
SADT (Self-Accelerating Decomposition Temperature): Typically around 50°C or lower - CRITICAL SAFETY PARAMETER.
Active Oxygen Content: ~9.18%
Flash Point: ~42°C(closed cup) –Highly Flammable Liquid.
Storage Requirements: MUST be stored at sub-ambient temperatures, often -15°Cto -10°Cor colder, in vented containers designed for peroxides. Extreme temperaturecontrol is paramount.
Mechanism: Unlocking Low-Temperature Radical Generation
tert-Butyl peroxypivalate (CAS 927-07-1)functions as a potent free radical initiator. Its critical feature isthe relatively weak O-O bond, which cleaves homolytically at significantly
lower temperaturescompared to many other common initiators (like AIBN or
higher-temperature peroxides). This cleavage produces:
1.tert-Butoxy Radical: (CH₃)₃C-O
2.Pivaloyl (Trimethylacetyl) Radical: (CH₃)₃C-C(=O)
The pivaloyl radical rapidly undergoesdecarboxylation, losing CO₂ to form anotherhighly reactive species:
1.tert-Butyl Radical: (CH₃)₃C
These radicals – primarily the tert-butoxy((CH₃)₃C-O) and tert-butyl ((CH₃)₃C) radicals – initiate polymerizationby attacking the double bonds of monomers like vinyl chloride, ethylene, and
styrene.
Why tert-Butyl Peroxypivalate (927-07-1)?
Key Advantages
This initiator's unique low-temperaturedecomposition profile offers compelling advantages:
1.Unmatched Low-Temperature Initiation: Its T₁/₂(10h) of ~45°C makes it exceptionallyeffective for initiating polymerizations at temperatures where many other
peroxides are essentially inert. This is crucial for specific processes.
2.High Initiator Efficiency: Generates radicalsefficiently within its low-temperature window, leading to better monomer
conversion and reduced initiator consumption compared to alternatives
attempting low-temp initiation.
3.Optimal Control in Specific Systems: Enablesexcellent control over polymerization rate and heat release in highly
exothermic reactions like suspension PVC polymerization, especially in the
early stages.
4.Influence on Polymer Properties: Cancontribute to achieving specific molecular weight distributions and particle
morphology in polymers like PVC, impacting final product performance (e.g.,
processability, impact strength).
5.Solubility: Excellent solubility in common monomers and solvents used inpolymerization processes.
Core Industrial Applications
Polyvinyl Chloride (PVC) Suspension Polymerization: This is the primary and most significant application for tert-Butyl peroxypivalate (CAS 927-07-1).
Role: It is exceptionally well-suited as a low-temperature initiatorincombination with higher-temperature initiators within multi-initiator systems.
Benefits:
Drives high conversion rates efficientlyearlyin the reaction cycle at temperatures typically ranging from 45-60°C.
Smoothens the overall reaction profile,improving temperature control and reducing the risk of localized
overheating/runaway reactions.
Contributes significantly to achievingconsistent and desirable PVC resin characteristics such as particle size
distribution, porosity ("fish-eyes" reduction), and bulk density.
These factors directly impact the processing behavior (dry flow, gelation time)
and performance (impact strength, thermal stability) of PVC in end products
like pipes, window profiles, films, cables, and bottles.
Other Polymerization Processes (Less Common):
Low-Density Polyethylene (LDPE): Can beused as a co-initiator in complex initiator packages for specific LDPE grades
produced in high-pressure reactors, though peroxydicarbonates are more typical
primary choices.
Solution Polymerization: Potential application insolution processes for synthetic rubbers or specific copolymers requiring
low-temperature initiation steps.
Graft Copolymerization: Useful where grafting needsto occur at lower temperatures to preserve substrate integrity.
Critical Safety Handling, Storage & Transportation
EXTREME CAUTION: tert-Butyl peroxypivalate (CAS 927-07-1) is aHIGHLY REACTIVE AND SENSITIVE ORGANIC PEROXIDE. IT POSES SIGNIFICANT FIRE,
EXPLOSION, AND HEALTH HAZARDS. ITS LOW SADT DEMANDS UTMOST CARE.
Critical Hazard: Self-Accelerating Decomposition (SADT ~50°C): This is the paramount safety concern. Decomposition is highlyexothermic and self-accelerating, meaning once started, it rapidly generates
heat and gas, potentially leading to catastrophic rupture of containers even
below 50°C. Even moderate temperatures (~40-50°C) can trigger decomposition if sufficient contaminant is present.
Fire & Explosion Hazards:
Class I Flammable Liquid (NFPA). Firehazard increases dramatically with temperature rise.
Organic Peroxide Type C: Definition: A peroxidewhich will detonate or deflagrate rapidly, exhibits thermal instability, or is
liable to undergo violent explosive decomposition when heated under
confinement. Requires specialized handling and transport.
Strong Oxidizer: Can ignite combustiblematerials and intensify fires. Fires involving peroxides are extremely
difficult to extinguish.
Reactivity Hazards: Reacts violently or explosively with:
Acids, bases, reducing agents,accelerators, metal ions (especially transition metals like copper, iron,
cobalt), amines, oxidizing agents.
Many organic contaminants. Can catalyzerunaway polymerization of monomers.
Health Hazards (Severe):
Skin/Eye Contact: Causes severe chemical burns (H314).
Skin Absorption: Harmful (H312).
Ingestion: Toxic if swallowed (H302).
Inhalation: Causes severe respiratory irritation, burns to the respiratorytract (H314, H330 - H330 "Fatal if inhaled" may apply based on
specific concentration and vapor generation potential). May cause damage to
organs (H372).
MANDATORY Safety Protocols:
Never Handle Without the Current SDS: Obtainand meticulously review the supplier's SafetyData Sheet (SDS) before ANY contact. Follow ALL instructions explicitly.
Strict Temperature Control (Storage & Handling): STORE AT VERY LOW TEMPERATURES (typically-15°C to-10°C,or colder as per SDS) IN APPROVED REFRIGERATORS/FREEZERS DESIGNED FOR FLAMMABLEPEROXIDES. Maintain strict temperature monitoring systems with alarms. Ensure
warm-up procedures (if allowed) are followed precisely per SDS. NEVER ALLOW MATERIAL TO REACH NEAR ROOM TEMPERATURE (20-25°C) UNCONTROLLED.
Personal Protective Equipment (PPE): Essential Minimum:
Cold-insulated chemical-resistant gloves(e.g., Viton®, Silver Shield® - CONFIRM SDS COMPATIBILITY).
Full-face shield worn OVER impact-resistantgoggles/splash goggles.
Impervious, flame-retardant full-bodysuit/coveralls and chemical-resistant apron.
Respiratory protection (NIOSH-approvedair-supplied respirator is STRONGLY RECOMMENDED for significant handling;
powered air-purifying respirator (PAPR) with appropriate organic vapor
cartridges only if air concentration is reliably below exposure limits and
approved by safety).
Safety footwear (impervious,chemical-resistant, steel toe/shank).
Engineering Controls:
Use ONLY in designated, well-ventilatedareas equipped with explosion-proofventilation (fume hoods with sufficient face
velocity) specifically designed for peroxides. Dedicated peroxide handling
room/cabinets are preferred.
Rigorous exclusion of air, moisture, andALL potential contaminants. Use dedicated, clean, inertequipment (stainless
steel 316L recommended). Ground and bond everything.
Eliminate all ignition sources (noelectrical equipment not rated for hazardous locations, no
flames/sparks/friction).
Conduct hazard reviews (e.g., HAZOP) beforescale-up.
Handling Procedures:
Highly Trained Personnel Only: Must beexperts in organic peroxide hazards and emergency response.
Minimize Quantities: Handle only theabsolute minimum needed immediately at the process location.
Strict Containment: Ensure closed transfersystems where possible. Handle under inert atmosphere (Nitrogen) if
feasible/recommended by SDS.
Avoid Shock/Friction/Abrasion: Preventimpacts and mechanical actions on the peroxide.
Never Return to Stock: Dispose of anymaterial not used immediately according to hazardous waste procedures.
Zero Tolerance for Contamination:Scrupulously clean spills immediately with inert absorbents (vermiculite,
sand). Use peroxide-specific spill kits.
Emergency Preparedness: Ready access to:
Deluge safety shower/eyewash station (<10 seconds).
Appropriate fire suppression (largequantities of water spray/fog to cool containers – DO NOT USE DRY CHEMICAL
DIRECTLY ON INVOLVED PEROXIDE; CO₂ or foam on surrounding fires. Specialist advice needed).
Inert absorbent.
Clearly defined and practicedemergencyprocedures for fire, explosion, large spill, and exposure.
Storage Specifications:
Temperature: MANDATORY: Very Low Temperature (e.g., -15°C to -10°C or colder), continuously monitored. Use qualified explosion-proof/coldstorage units.
Containers: Original supplier containers ONLY (properly vented). Store upright.Never use damaged or unvented containers larger than recommended by SDS.
Segregation: Store ALONE, physically separated by walls/fire barriers in adedicated cabinet/refrigerator away from ALL incompatible materials
(flammables, combustibles, acids, bases, metals, reducing agents, promoters,
monomers).
Shelf Life & Stability: Stability is LIMITED.STRICTLY observe manufacturer's expiration date. Visually inspect containers
frequently (e.g., daily) for ANY signs of decomposition: pressure
buildup/bulging, discoloration, unusual odor, gas evolution,
crystallization/precipitate formation. DO NOTOPEN! Quarantine and contact supplier/professional immediately.
Transportation Requirements:
Dangerous Goods Classification (Example - Verify SDS!):
UN Number: UN3105
Proper Shipping Name: ORGANIC PEROXIDE TYPE C,LIQUID, TEMPERATURE CONTROLLED
Hazard Class: 5.2 (Organic Peroxide)
Subsidiary Risk: 4.1 (Flammable Solid) OR 3 (Flammable Liquid) - Confirm SDS.
Packing Group: II
Strict Conditions: MUST be shipped refrigerated at VERY LOW TEMPERATURES (e.g., ≤ -20°C) using UN-specificationinsulated "refrigerated" overpacks designed for temp control and
pressure release.
Regulations: Compliance with IMDG Code (sea), IATA/ICAO (air - restrictionsapply), ADR/RID (road/rail Europe), and DOT 49 CFR (US) is non-negotiable.
Requires specialized expertise.
Regulatory Compliance
Navigating the regulatory framework iscrucial:
GHS Classification: Expect Hazard Statements: H242 (Heating may cause a fire orexplosion), H314 (Causes severe skin burns and eye damage), H330 (Fatal if
inhaled), H372 (Causes damage to organs) - Verify specific classification on
SDS.
Mandatory Documents: Safety Data Sheet (SDS) is essential. Technical Data Sheet (TDS)may provide application-specific info.
OSHA (USA): Governed by Hazard Communication Standard (HCS 2012), potentiallyProcess Safety Management (PSM) for large quantities, and relevant exposure
limits. Strict lockout/tagout and confined space entry may apply to associated
equipment.
EPA (USA): Subject to Toxic Substances Control Act (TSCA) inventory status.May trigger reporting under SARA Title III (EPCRA) Sections 302 (EHS), 311/312
(MSDS/Tier II reporting), and 313 (TRI reporting). CERCLA spill reporting
requirements.
DOT (USA Transport): Regulated under 49 CFR Parts 100-185.
REACH (EU): Requires registration and authorization under specific conditions.Safety information in extended SDS.
CLP (EU): Classified under Regulation (EC) No 1272/2008.
Global Compliance: Adherence to all national and local regulations (e.g., WHMIS 2015in Canada, DSEAR in UK, DG Regulations in other regions).
Procurement Insights and Major Suppliers
Sourcing tert-Butylperoxypivalate (CAS 927-07-1) requires partnering with specialized, reputable chemical suppliersdue to the extreme hazards and stringent handling requirements.
Leading Global Manufacturers & Suppliers:
Arkema (Luperox® 11 brand - Luperox 11 isalso used for CAS 29240-17-3 - CONFIRM SPECIFIC CAS (927-07-1) WITH SUPPLIER)
Shandong Do Sender Chemicals Co.,Ltd. Perkadox® 24 - MajorBrand Name for CAS 927-07-1)
NOF Corporation (Perbutyl PV)
Akpa Kimya (AKPEROX TBPP)
MPI Chemie
Nouryon (Perkadox 24)
Zhonglan Industrial Co., Ltd.
Critical Purchase Considerations:
1.
Specific CAS Confirmation (927-07-1):Explicitly confirm the CAS number on all quotes, packaging, and documentation.
Do not confuse with higher-temperature initiators or similarly named products
like Luperox 11/Perkadox BP when referring to CAS 29240-17-3.
2.
Supply Chain Stability & Reliability: Due tohazards and cold chain requirements, choose suppliers with proven logistics
expertise and contingency planning.
3.
Quality Assurance: Require Certificates of Analysis (CoA) detailing purity, activeoxygen content, and impurities.
4.
Packaging Integrity: Insist on validated vented containers designed forultra-low-temperature storage and transport. Confirm compatibility/correctness
upon delivery.
5.
Technical & Safety Support: Evaluatethe supplier's ability to provide responsive technical assistance and safety
guidance.
Conclusion
tert-Butyl peroxypivalate (CAS 927-07-1) is anindispensable low-temperature free radical initiator, critically enabling the
efficient and controlled production of suspension PVC resins with desired
performance characteristics. Its unique ability to decompose and initiate
chains effectively below 50°C provides processadvantages unmatched by many alternatives. However, this capability comes with
inherent high risks – primarily its propensity forexplosive self-accelerating decomposition at very moderate temperatures.
Handling this material is NOT routine. Success hinges on an absolute, uncompromising commitment to thestrictest safety protocols: rigorous adherence to the SDS, continuous expert
training, robust engineering controls (especially temperature control),
specialized PPE, and meticulous operational procedures. For applications
demanding reliable low-temperature initiation, tert-Butylperoxypivalate (927-07-1) remains a powerful solution, but only when treated with the extremerespect its hazards demand. Its safe and effective use is a testament to
sophisticated chemical engineering and disciplined industrial hygiene.
DEMAND and thoroughly REVIEW the specific Safety Data Sheet (SDS)for tert-Butyl peroxypivalate (CAS 927-07-1) BEFORE ANY procurement, handling,
or use!