Hexamethyldisiloxane

Hexamethyldisiloxane (CAS 107-46-0), commonly referenced as HMDSO, is a low-viscosity silicone fluid used as a solvent, carrier, and surface-modifying agent in specialty chemical manufacturing.

Where is Hexamethyldisiloxane used?

• Coatings and release liners: reactive diluent.
• Processing solvent improving flow and substrate wetting.
• Personal care: lightweight carrier fluid in skin-feel emollients and dry-touch formulations, functioning as a fast-evaporating volatile carrier and spreading agent in antiperspirant deodorants, lotions, and hair care products.
• Used to adjust the residence time of silicone on the skin when combined with dimethicone fluids.
• Adhesives and sealants: solvent for silicone polymers and surface primer.
• Plasma-enhanced chemical vapor deposition uses HMDSO as a precursor to deposit hydrophobic or barrier silica coatings on plastics and films.
• Applied in water-repellent coatings and lubricants.
• Functions as an end-blocking chain terminator to control polymer chain length during polydimethylsiloxane (PDMS) production.

Formulation notes

• Represents the lowest viscosity grade among volatile silicones, followed by higher grades MDM (1 cSt) and MD2M (1.5 cSt).
• Shows incompatibility with strong acids, strong bases, strong oxidizing agents, and oxygen.

Typical specification

• Purity by GC is typically at least 99%.
• Kinematic viscosity is approximately 0.65 cSt.

Regulatory status

• Listed on the US TSCA inventory.
• Classified as a flammable liquid under UN 1993 and regulated under DOT, IATA, and IMDG dangerous goods transportation rules.

Storage, packaging and handling

• Supplied in 5-gallon pails, 55-gallon drums, and 275-gallon IBC totes.
• Hygroscopic material that must be kept in tightly closed containers within dry, well-ventilated spaces away from heat sources to avoid vapor accumulation.

Frequently asked questions about Hexamethyldisiloxane

What is the water solubility of hexamethyldisiloxane?

Water solubility is very low, measuring 0.93 mg/L at 25 °C.

Is high-purity material available for specialized analytical work?

An NMR grade with 99.7% purity is available on the market.

Can it be utilized for industrial surface cleaning?

It serves as a low-residue cleaning process solvent for electronics and coatings applications.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.