Octamethylcyclotetrasiloxane (D4)
Technical-grade Octamethylcyclotetrasiloxane D4 (CAS 556-67-2) supplied wholesale by Zyntex. Cyclic siloxane monomer for silicone fluids, elastomers, resins and emulsions, with EU regulatory information. CoA and SDS with every lot.
Description
Octamethylcyclotetrasiloxane Product Overview
Octamethylcyclotetrasiloxane (C8H24O4Si4), known as D4, is a clear, colorless, low-viscosity liquid that boils at about 175°C. It is a ring of four silicon–oxygen units, each carrying two methyl groups, and is produced from methylchlorosilanes, which in turn come from Silicon (powder).
Silicone producers use D4 as the main monomer for ring-opening polymerization to polydimethylsiloxane (PDMS) fluids, elastomers, resins and emulsions. These silicones go into sealants, rubber parts, coatings, textiles and personal care products.
D4 is classified in the EU as persistent, bioaccumulative and toxic and is suspected of damaging fertility. Its use in wash-off cosmetics is restricted, and a REACH restriction extends limits to leave-on cosmetics and many consumer products. Zyntex therefore supplies D4 for industrial silicone production, where it is handled in closed systems.
Key Applications of Octamethylcyclotetrasiloxane
Main application areas:
🏭 Silicone Polymers
Monomer for PDMS fluids, elastomers and resins.
🧪 Chemical Intermediate
Raw material for functional siloxanes.
🧴 Silicone Emulsions
Starting material for silicone emulsions.
🔬 Research
Monomer for polymerization studies.
Octamethylcyclotetrasiloxane Technical Specifications
| Parameter | Standard Value |
|---|---|
| Product Name | Octamethylcyclotetrasiloxane (D4) |
| CAS Number | 556-67-2 |
| EC Number | 209-136-7 |
| Molecular Formula / Weight | C8H24O4Si4 / 296.62 g/mol |
| Grade | Technical Grade |
| Boiling Point | approx. 175°C |
| Documents | CoA and SDS with every lot |
⚠️ Safety & Handling: Flammable liquid; suspected of damaging fertility; may cause long-lasting harmful effects to aquatic life. Use in closed systems with good ventilation, wear gloves and eye protection, and prevent release to the environment. Store in tightly closed containers away from ignition sources. Always consult the Safety Data Sheet (SDS) for full classification and handling instructions.
Frequently Asked Questions
Can D4 be used in cosmetics?
Its use is restricted in the EU: limited in wash-off cosmetics and, under a newer REACH restriction, in leave-on cosmetics and many consumer products. It is supplied mainly for industrial silicone production.
What is D4 used for?
Mainly as the monomer for producing polydimethylsiloxane silicones by ring-opening polymerization.
How can I get a price and documents?
Prices depend on quantity, packaging and destination. Contact us with your required volume to receive a quotation together with the CoA and SDS.
