PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Methylchlorodisilane; (Chloromethyldisilane) | 68937-17-7 |
4.00
3.00
|
||||||||||
| Formula | Synonyms | |||||||||||
| CH7ClSi2 | ||||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 110.75 |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.45 | 5.5 | 25 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 2.0 | 25 | 110 |
Technical Basis
The CASRN 68937-17-7 is defined by the ECHA as a mixture of 1,1,2,2-tetrachloro-1,2-dimethyldisilane (C2H6Cl4Si2, CASRN: 224-844-6), 1,1,2-trichloro-1,2,2-trimethyldisilane (C3H9Cl3Si2, CASRN: 236-870-5), and 1,2-dichloro-1,1,2,2-tetramethyldisilane (C4H12CL2Si2¬, CASRN: 224-400-1), all of which hydrolyze rapidly and are intermediates for selective chlorosilane synthesis. A review of available sources did not identify exposure limits or acute toxicity data for the any of the chemicals in this mixture; however, AEGLs have been developed for chlorosilanes (CASRN: 993-00-0). Of these, the most conservative values AEGLs were selected (tetrachlorosilanes, refer to Table 3-1), corresponding to the maximum number of chlorines available, given that hydrogen chloride generated is the primary risk of chlorosilanes. These AEGLs were selected as TEELs due to their priority among the emergency exposure limits (Section 1).
• TEEL-1 = AEGL-1 (chlorosilanes, CASRN: 993-00-0)
• TEEL-2 = AEGL-2 (chlorosilanes, CASRN: 993-00-0)
• TEEL-3 = AEGL-3 (chlorosilanes: CASRN: 993-00-0)
This review generated TEEL values that are less conservative than those found in Rev. 29A. The Rev. 29A TEEL-3 basis was a rat LC, however that data was not found in the review.
• TEEL-1 = AEGL-1 (chlorosilanes, CASRN: 993-00-0)
• TEEL-2 = AEGL-2 (chlorosilanes, CASRN: 993-00-0)
• TEEL-3 = AEGL-3 (chlorosilanes: CASRN: 993-00-0)
This review generated TEEL values that are less conservative than those found in Rev. 29A. The Rev. 29A TEEL-3 basis was a rat LC, however that data was not found in the review.
References
https://echa.europa.eu/de/registration-dossier/-/registered-dossier/9975/1/1
https://pubchem.ncbi.nlm.nih.gov/compound/78276
1,1,2,2-Tetrachloro-1,2-dimethyldisilane (CASRN: 224-844-6). https://pubchem.ncbi.nlm.nih.gov/compound/1_1_2_2-Tetrachloro-1_2-dimethyldisilane.
1,1,2-trichloro-1,2,2-trimethyldisilane (CASRN: 236-870-5). https://pubchem.ncbi.nlm.nih.gov/compound/1_1_2-Trichloro-1_2_2-trimethyldisilane.
1,2-dichloro-1,1,2,2-tetramethyldisilane (CASRN: 224-400-1). https://pubchem.ncbi.nlm.nih.gov/compound/Disilane_-1_2-dichloro-1_1_2_2-tetramethyl.
Chlorosilane AEGLs, refer to supplementary report, Table 3-1: https://www.epa.gov/aegl/methyl-chlorosilane-results-aegl-program
Semenov, V.V., Ladilina, E.Y., Chesnokova, T.A. et al. Reactions of methylchlorodisilanes with Grignard reagents. Russ Chem Bull 44, 927–930 (1995). https://doi.org/10.1007/bf00696930