Product Name: Cyclopentasiloxane
Synonyms: Decamethylcyclopentasiloxane, D5
Chemical Formula: C10H30O5Si5
Molecular Weight: 370.77 g/mol
CAS Number: 541-02-6
Intended Use: Ingredient for personal care products, cosmetics, water repellent treatments, and polishes
Company: Refer to the product label for manufacturer contact
Emergency Contact Number: Check with the product supplier or local regulatory agency for region-specific emergency numbers
Classification: Not classified as hazardous according to GHS criteria for most jurisdictions
Physical Hazards: Can form flammable vapors at high temperatures
Health Hazards: Short-term exposure may cause mild irritation to eyes or skin; inhalation of high concentrations could cause dizziness
Labels: Not expected to generate GHS-pictograms under normal handling conditions
Precautionary Statements: Avoid heat, sparks, open flames, and static discharge; use with adequate ventilation; avoid prolonged inhalation or skin contact
Signal Word: None assigned (based on most country regulations); always review current local standards
Cyclopentasiloxane: Concentration varies by grade—usually ≥ 98%
Other Siloxanes: May contain traces of octamethylcyclotetrasiloxane (D4) and other cyclic siloxanes at amounts below 2%
Impurities: Contains only minimal manufacturing impurities; no hazardous additives
Substance Type: Single chemical substance for regulatory purposes
Inhalation: Move to fresh air; support breathing as needed, seek medical attention for persistent symptoms like dizziness or headache
Skin Contact: Wash affected area with soap and water; remove contaminated clothing; seek medical advice if irritation persists
Eye Contact: Rinse cautiously with water for several minutes; remove contact lenses if present and easy to do
Ingestion: Rinse mouth, do not induce vomiting; seek medical advice if large quantity swallowed or symptoms develop
Exposed Persons: Provide supportive care according to individual symptoms; keep emergency services informed about the material involved
Suitable Extinguishing Media: Carbon dioxide, dry chemical, alcohol-resistant foam, water spray
Unsuitable Extinguishing Media: Direct water jet (can spread burning liquid)
Special Hazards: May produce silicon dioxide, carbon oxides, and formaldehyde under fire conditions
Protective Equipment: Firefighters wear self-contained breathing apparatus and full protective suit
Firefighting Instructions: Approach fire from upwind; contain run-off to prevent environmental contamination; keep nearby containers cool with water spray
Unusual Fire Hazards: Vapors may form explosive mixtures with air at elevated temperatures
Personal Precautions: Avoid inhalation, use protective gloves and goggles; ventilate spill area
Environmental Hazards: Prevent uncontrolled entry into water courses or drains
Clean-Up Methods: Absorb with earth, sand, or inert material; collect into suitable containers for disposal; wash contaminated area with water and detergent
Decontamination: Test for slippery surfaces after cleanup; use spill control pads if available
Disposal: Dispose of according to local, state, and federal regulations for siloxane wastes
Safe Handling: Use in a well-ventilated area; avoid contact with strong oxidizing agents; prevent static discharge by grounding equipment; routinely check for leaks or spills
Hygiene Practices: Wash hands and face after handling; do not eat, drink, or smoke during use
Storage Conditions: Store in a dry, cool, well-ventilated place; keep container tightly closed when not in use
Packaging Materials: Store in compatible containers (glass, stainless steel, HDPE)
Storage Life: Monitor shelf life based on manufacturer's guidelines, usually stable for two years or more
Exposure Limits: No established OEL or TLV in most jurisdictions; use general chemical ventilation recommendations
Engineering Controls: Install local exhaust ventilation in enclosed processing areas
Personal Protective Equipment: Safety goggles, chemical-resistant gloves (nitrile or PVC), lab coats or aprons as needed
Respiratory Protection: Use an approved organic vapor respirator for high vapor concentrations or accidental release scenarios
Environmental Exposure: Implement measures to prevent discharge into the environment, including secondary containment for bulk storage
Physical State: Clear, colorless liquid
Odor: Mild, slightly sweet
Odor Threshold: No established threshold
Melting Point: Approximately -40°C
Boiling Point: 210–212°C at 1 atm
Flash Point: 77–81°C (closed cup method)
Evaporation Rate: Moderate (compared to water)
Flammability: Combustible liquid
Upper/Lower Flammability Limits: Not well defined, but flammable at vapor concentrations above flash point in air
Vapor Pressure: 0.2–0.3 hPa at 25°C
Vapor Density: 6.94 (air = 1)
Relative Density: About 0.95 g/cm³ at 25°C
Water Solubility: Very low (<0.01 mg/l)
Partition Coefficient (log Kow): Above 6, highly lipophilic
Decomposition Temperature: Above 300°C
Chemical Stability: Stable under recommended storage and handling conditions
Reactivity: Can react with strong acids, bases, or oxidizing agents
Conditions to Avoid: High heat, open flames, sources of ignition, exposure to moisture
Hazardous Reactions: May release hazardous decomposition products at high temperature or under fire conditions, including formaldehyde, silicon oxides, and low molecular weight hydrocarbons
Polymerization: Product does not polymerize spontaneously
Acute Toxicity: Low oral and dermal toxicity; LD50 (oral, rat) > 5000 mg/kg
Skin Corrosion/Irritation: Usually not irritating to skin with standard use; prolonged exposure can dry skin
Serious Eye Damage/Irritation: Possible mild, transient irritation in direct contact
Respiratory Effects: Inhalation of mist or vapor at high levels may cause mild, reversible respiratory symptoms
Chronic Effects: No long-term adverse effects noted in routine industrial use
Carcinogenicity: Not classified as a carcinogen by IARC, NTP, or OSHA
Mutagenicity: Genetic toxicity studies show negative results
Reproductive Toxicity: No clear evidence of reproductive or developmental effects in animal testing
Ecotoxicity: Aquatic organisms may be impacted at high concentrations; D5 is not acutely toxic at environmental levels found during typical use
Persistence and Degradability: Breaks down slowly in the environment due to hydrolysis and photolysis processes
Bioaccumulative Potential: High potential for bioaccumulation in aquatic organisms, given log Kow > 6
Mobility in Soil: Tends to bind strongly to soil particles, limiting movement to groundwater
Behavior in Water: Floats on water surface due to density; potential for long-range transport in air under certain conditions
Other Ecological Effects: Discharge into the environment should be minimized to reduce long-term build-up in sediment and aquatic food webs
Waste Disposal Methods: Dispose through licensed waste management providers, using incineration or approved chemical landfill as per local regulations
Container Disposal: Empty containers may retain product residues; triple-rinse before disposal or recycling
Special Precautions: Do not dump into sewers, water systems, or unapproved landfills
Relevant Regulations: Consult local, regional, and national waste disposal requirements for specific guidance or restrictions
UN Number: Not regulated as a dangerous good under UN Model Regulations
Proper Shipping Name: Cyclopentasiloxane, not regulated
Transport Hazard Class: Not classified
Packing Group: Not assigned
Environmental Hazards: Not regulated for transport, but best practices advise prevention of spills or container leaks
Special Precautions: Keep away from heat or ignition sources, use sealed containers and appropriate labeling for bulk shipments
Global Inventories: Listed on TSCA (USA), EINECS/ELINCS (EU), DSL (Canada), AICS (Australia), ENCS (Japan), and similar global listings
Major Regulations: Not classified as a hazardous substance under OSHA, EU CLP, or Canadian WHMIS standards for most uses
SAR Regulation: Not subject to prioritized risk assessment or restriction in most regions
Community Guidelines: Comply with local occupational health, safety, and environmental regulations for handling, use, and storage
Labeling Obligations: Follow product-specific safety and precaution labeling for consumer and industrial use as applicable
