Perodox® 44B - Acetyl Acetone Peroxide

The molecular formula is C5H6O4 with a molecular weight of 130.1 g/mol. The compound contains 46.15% carbon, 4.65% hydrogen, and 49.20% oxygen by elemental composition.

The CAS Registry Number is 37187-22-7. This identifier is used in chemical databases, regulatory documents, and safety data sheets globally.

Commercial formulations are typically supplied as solutions with concentrations ranging from 33.5% to 36.5% in non-hazardous solvents such as dimethyl phthalate or alcohols.

The active oxygen content typically ranges from 4.0% to 4.2% for commercial formulations, measured via iodometric titration (ASTM E298).

Specific gravity is 1.024 at 25°C, and viscosity is approximately 21 mPa·s at room temperature.

Boiling point is 93°C at 55 torr (7.33 kPa), and flash point is 78°C.

It is soluble in most organic solvents (alcohols, esters, ketones, aromatic hydrocarbons) and has limited water solubility (5-10 g/L at 20°C).

The IUPAC name is 3,5-Dioxa-1,2-dioxane-4,6-dione.

IR absorption at 1780-1820 cm⁻¹ (C=O stretch) and 880-900 cm⁻¹ (O-O stretch); ¹H NMR signals at δ 2.2-2.4 ppm (methyl protons) and δ 5.2-5.4 ppm (methine proton).

Thermal decomposition follows first-order kinetics with activation energy of 120-140 kJ/mol, producing acetone, carbon dioxide, methane, and water. Half-life is ~10 hours at 80°C.

SADT is 60°C, the lowest temperature at which self-accelerating decomposition may occur in shipping packages.

H242 (Heating may cause a fire), H314 (Causes severe skin burns and eye damage), H335 (May cause respiratory irritation), H360D (May damage the unborn child).

Chemical-resistant gloves (nitrile/butyl rubber), safety goggles, face shield, protective clothing, and respiratory protection if ventilation is inadequate.

Immediately flush eyes with water for 15-20 minutes, holding eyelids open. Remove contact lenses if present. Seek immediate medical attention.

Use water spray, alcohol-resistant foam, dry chemical, or CO₂ extinguishers. Cool containers with water spray. Do not use direct water jets. Fight fire from upwind protected location.

Oral LD₅₀ (rat): 500-1000 mg/kg. Dermal LD₅₀ (rabbit): 400-800 mg/kg. Inhalation LC₅₀ (rat, 4h): >2 mg/L.

Inhalation: cough, sore throat, respiratory irritation. Skin: redness, pain, severe burns. Eyes: redness, pain, severe burns, permanent damage. Ingestion: abdominal pain, nausea, vomiting.

Local exhaust ventilation, general ventilation (6-12 air changes/hour), explosion-proof electrical equipment, safety showers/eye wash within 10 seconds travel time.

Evacuate area, contain with inert absorbent (vermiculite/sand), collect in containers for disposal, wash area with water and 5% sodium thiosulfate solution. Never use combustible absorbents.

Reducing agents, organic materials, powdered metals (Al, Cu, Zn), acids, bases, halides, sulfur compounds, amines, strong oxidizing agents. Contact may cause fire/explosion.

Free-radical initiator for vinyl polymerization, curing agent for unsaturated polyester resins, cross-linking agent for elastomers, oxidizing agent in organic synthesis.

Used at 1-3% concentration with cobalt accelerators (0.1-0.5% cobalt octoate). Gel times: 10-30 minutes at 25°C. Post-cure at 60-80°C for 2-4 hours optimizes properties.

Initiates free-radical polymerization via thermal decomposition (homolytic O-O bond cleavage) or redox initiation with reducing agents. Half-life: ~10 hours at 80°C.

Polymerization: 0.1-2.0% on monomer. Resin curing: 1-3% on resin. Adhesives: 0.5-2.0%. Modifier: 0.01-0.5%.

Cure rate follows Arrhenius relationship with activation energy 80-100 kJ/mol. Gel time decreases ~50% per 10°C increase. Optimal cure temperature: 20-80°C.

Good solubility in organic media, balanced reactivity, effective at moderate temperatures, compatibility with accelerators, lower odor, good storage stability.

Poly(methyl methacrylate), polystyrene, poly(vinyl acetate), PVC, unsaturated polyesters, acrylic adhesives, cross-linked polyethylene.

Forms redox pairs with metal ions (Co²⁺, Fe²⁺), amines (dimethylaniline), or sulfur compounds. Enables polymerization at -20°C to 40°C.

Pure compound: 9+ months at 2-8°C. In resin formulations: 1-3 months at 25°C. Decomposition rate: 1-2% per month at 25°C without stabilizers.

Active oxygen content (iodometric titration), assay (HPLC/GC), water content (Karl Fischer), acidity/alkalinity, viscosity, specific gravity, color, impurity profile, stability tests.

Provides longer gel times (20-50% longer), lower peak exotherm (5-15°C lower), better depth of cure, different sensitivity to inhibitors compared to MEKP.

Inhibitors (hydroquinone, MEHQ) extend induction period. Induction increases ~10 minutes per 50 ppm hydroquinone at 80°C. Oxygen acts as radical scavenger.

Kinetic chain length ν = kp[M]/(2fkd[I])¹ᐟ². Typical ν = 1000-5000 for styrene at 80°C with 0.1M initiator. Initiator efficiency f = 0.6-0.8.

Decomposition rate increases with solvent polarity. Relative rates: water (1.0) > methanol (0.8) > acetone (0.6) > toluene (0.4) > hexane (0.3).

100 hours at 70°C, 10 hours at 80°C, 1 hour at 100°C, 6 minutes at 130°C. Half-life decreases ~10× per 20-25°C increase.

Transition metals catalyze decomposition: Co²⁺ (100-1000× acceleration), Fe²⁺ (50-200×), Cu⁺ (20-100×). Chelating agents (EDTA) moderate effects.

Oxygen balance to CO₂: -92.3%. Oxygen balance to CO: -46.2%. Negative values indicate fuel-rich composition requiring external oxidizer.

Primary products: acetone (40-60%), CO₂ (20-30%), methane (10-20%), acetic acid (5-10%), water. Minor products: acetyl radicals, methyl radicals, CO.

Not classified as detonating substance. May deflagrate under confinement when heated above SADT. Critical diameter not applicable.

Store at 2-8°C (refrigerated). Maximum temperature: 25°C. Protect from sunlight, heat, ignition sources. Keep containers tightly closed. Store separately from incompatibles.

HDPE, polypropylene, stainless steel 316, aluminum, glass, PTFE. Avoid: copper, brass, bronze, carbon steel, natural rubber.

Transport as UN 3105, Organic peroxide type D. Keep below 30°C. Protect from damage, sunlight, heat. Segregate from incompatibles. Follow hazardous material regulations.

Gas evolution, pressure buildup, discoloration (yellow-brown), solids formation, unusual odors (acetic acid/acetone), temperature rise, container bulging.

Small quantities: Dilute ≥10:1 with water, add reducing agent (sodium sulfite/thiosulfate), test with peroxide strips. Large quantities: Contact licensed hazardous waste contractor.

Vapor pressure <1 mmHg at 20°C. Evaporation rate <0.1 (n-butyl acetate=1). Vapor density >1 (heavier than air).

Use spark-proof tools, minimal quantity, dedicated equipment, grounding, ventilation. Return samples to refrigeration immediately.

Shelf life: 9 months at 2-8°C. Retest: 6 months. After opening: 30 days at 2-8°C, 7 days at 25°C.

Triple rinse with water, fill with 5% sodium carbonate/thiosulfate for 24 hours, drain, puncture/crush, dispose as hazardous waste or recycle.

NFPA 430: Store in dedicated peroxide cabinet/refrigerator. Maximum 25 lbs outside cabinet. Separation: 20 ft from incompatibles. Fire detection/suppression required.

29 CFR 1910.119 (PSM if ≥10,000 lbs), 1910.106 (flammable liquids), 1910.1200 (HazCom), 1910.132-138 (PPE).

Health: 3, Flammability: 2, Instability: 4, Special: OXY (Oxidizer).

Proper Shipping Name: ORGANIC PEROXIDE TYPE D, LIQUID. Hazard Class: 5.2. UN: 3105. Packing Group: II. Limited Quantity: 30 mL.

Registration required for ≥1 ton/year. Classification: Ox. Liq. 2, Skin Corr. 1B, STOT SE 3, Repr. 1B. SDS required. Exposure scenarios needed.

Listed on TSCA Inventory. PMN not required (existing chemical). Sections 8(a)/(d) reporting may apply. Export notification under Section 12(b).

Acute aquatic toxicity EC₅₀ (Daphnia magna): 10-100 mg/L (Category 2). log Pₒw ~0.8-1.2. Not classified as PBT/vPvB.

​ No established OELs (OSHA PEL, ACGIH TLV, NIOSH REL). Manufacturer recommends ALARA (As Low As Reasonably Achievable).

RCRA D001 (ignitable), D003 (reactive), possibly D002 (corrosive). Manifest required (EPA Form 8700-22). Land disposal restricted.

Signal word: Danger. Pictograms: Flame over circle, Corrosion, Health hazard. H-statements: H242, H314, H335, H360D.

NFPA 430: Maximum 25 lbs outside cabinet. Separation 20 ft from incompatibles. Fire detection/suppression required. No smoking signs.