Substances

As part of of CES's preparatory work, a list of about 200 silanes and siloxanes manufactured or imported into the European Union has been identified by member companies.

REACH imposes an obligation to register monomers in imported polymers, even if they are in reacted form. Those monomers were also identified to CES by its members.

In order to help companies in their pre-registration tasks, CES is providing below a list of common monomers that are used in the manufacturing of most of silicone polymers:

List of Monomers Used in the Manufacturing of Silicones
CAS Number EC Number ChemicalName
000075-54-7 200-877-1 Dichloro(methyl)silane
000075-77-4 200-900-5 Chlorotrimethylsilane
000075-78-5 200-901-0 Dichloro(dimethyl)silane
000075-79-6 200-902-6 Trichloro(methyl)silane
000098-13-5 202-640-8 Trichloro(phenyl)silane
000124-70-9 204-710-3 Dichloro(methyl)(vinyl)silane
000556-67-2 209-136-7 Octamethylcyclotetrasiloxane
001066-35-9 213-912-0 Chlorodimethylsilane
001185-55-3 214-685-0 Trimethoxy(methyl)silane
002530-83-8 219-784-2 [3-(2,3-epoxypropoxy)propyl]trimethoxysilane
002768-02-7 220-449-8 Trimethoxyvinylsilane
010025-78-2 233-042-5 Trichlorosilane
000078-10-4 201-083-8 Tetraethyl orthosilicate
000078-08-0 201-081-7 Triethoxy(vinyl)silane
000080-10-4 201-251-0 Dichloro(diphenyl)silane
000141-57-1 205-489-6 Trichloro(propyl)silane
000149-74-6 205-746-2 Dichloro(methyl)(phenyl)silane
000675-62-7 211-623-4 Dichloromethyl(3,3,3-trifluoropropyl)silane
000681-84-5 211-656-4 Tetramethyl orthosilicate
000682-01-9 211-659-0 Tetrapropyl orthosilicate
000780-69-8 212-305-8 Triethoxy(phenyl)silane
001067-25-0 213-926-7 Trimethoxypropylsilane
001112-39-6 214-189-4 Dimethoxydimethylsilane
001719-58-0 217-007-1 Chlorodimethylvinylsilane
001760-24-3 217-164-6 N-(3-(trimethoxysilyl)propyl)ethylenediamine
002550-02-9 219-842-7 Triethoxypropylsilane
003179-76-8 221-660-8 3-(diethoxymethylsilyl)propylamine
013822-56-5 237-511-5 3-(trimethoxysilyl)propylamine
023410-40-4 245-642-4 N-[3-(dimethoxymethylsilyl)-2-methylpropyl]ethylenediamine
003069-29-2 221-336-6 N-[3-(dimethoxymethylsilyl)propyl]ethylenediamine
002996-92-1 221-066-9 Trimethoxyphenylsilane
006843-66-9 229-929-1 Dimethoxydiphenylsilane
016753-62-1 240-816-6 Dimethoxymethylvinylsilane
003027-21-2 221-192-4 Dimethoxymethylphenylsilane

Preregistration requires the following data to be submitted before December 1, 2008:

  • Name of substance
  • CAS-Number
  • Name of the company, which intends to pre-register
  • Contact address of the company, which intends to pre-register
  • Envisaged tonnage band

For companies which are not monomers manufacturers or importers, it would be helpful adding a remark to the pre-registration entry form provided by ECHA. The new situation is likely to overload the REACH IT-system by the drastically increased number of pre-registrations.

At present, the silanes and siloxanes are grouped in several categories according to their chemical structure:

  • monoalkoxysilanes
  • dialkoxysilanes
  • trialkoxysilanes
  • tetraalkoxysilanes
  • monochlorosilanes
  • dichlorosilanes
  • trichlorosilanes
  • tetrachlorosilane
  • linear siloxanes
  • cyclic siloxanes

Categorisation may change as a function of the data showing the benefits of further groupings. It is important to note that categorization does not imply identical classification and labeling, or that the differences between substances belonging to a category are not recognized.

The grouping of these substances in categories will enable to optimize the use of QSAR and read-across techniques to minimize additional testing.

This implies that any data (physico-chemical, toxicological or ecotoxicological) on any substance belonging to any of these categories (whether they will be registered or not) may be useful and therefore might have financial value. Data owners are therefore encouraged to identify themselves to CES.

Silicones (polydimethylsiloxanes and other resins) are considered to be polymers and at the present do not fall under the scope of REACH to the extent that they meet the REACH polymer definition. The starting materials (monomers) should be considered. It is expected that the exemption of silicones from the scope of REACH will have to be documented on a case by case basis.

Top of page