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Dimethyl-bis(trimethylsilyloxy)silane

  • Silicones
  • CAS 107-51-7
  • IUPAC: Dimethyl-bis(trimethylsilyloxy)silane

Dimethyl-bis(trimethylsilyloxy)silane (CAS 107-51-7) appears in 1 of the 2,122 car-care products CarCareTruth tracks (as of August 2026).

No GHS hazard classifications at mixture-level concentrations below 1%. Used as a process chemical and coupling agent in silicone emulsions. Not a skin sensitizer, not a respiratory sensitizer.

Dimethyl-bis(trimethylsilyloxy)silane (CAS 107-51-7) is a low-molecular-weight linear siloxane containing two trimethylsilyloxy end groups on a dimethylsilane core. In water-based silicone emulsions it acts as a reactive diluent and may provide silanol-mediated bonding to silica surfaces upon cure. It is distinct from amorphous silicon dioxide (SiO2) — the compound is a siloxane, not a metal oxide. At concentrations of 0.5–1% in a water-based product applied to exterior surfaces, the exposure to both human health and aquatic systems is very low.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
no
Biodegradable
no
Bioaccumulative
no
Persistent
no
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
5/5
Purpose: Low-molecular-weight linear siloxane used as a reactive coupling agent and silane crosslinker in water-based silicone emulsions

Common questions about Dimethyl-bis(trimethylsilyloxy)silane

What is Dimethyl-bis(trimethylsilyloxy)silane used for in car care?
Low-molecular-weight linear siloxane used as a reactive coupling agent and silane crosslinker in water-based silicone emulsions
Is Dimethyl-bis(trimethylsilyloxy)silane a VOC?
No. Dimethyl-bis(trimethylsilyloxy)silane is not classified as a volatile organic compound (VOC).
Is Dimethyl-bis(trimethylsilyloxy)silane on California's Proposition 65 list?
No. Dimethyl-bis(trimethylsilyloxy)silane is not on California's Proposition 65 list.

1 product contain this

Related

Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.