PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Methyltriacetoxysilane 4253-34-3
15.01
11.01
15.02
4.07
11.00
7.01
Formula Synonyms
C7H12O6Si
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
220.25 40.5 1.175 @ 20°C
PAC Values
PAC Values (Original Units: mg/m3)
PAC-1 PAC-2 PAC-3
6.2 68 410
Converted PAC Values (ppm)
PAC-1 PAC-2 PAC-3
0.69 7.5 46
Technical Basis
Analysts explored toxicity and exposure limit data, applying Tables 3.1, 3.4, and 3.5 from the handbook. Chemical safety data sheets include GHS hazards of one, approximately equivalent to an HHR=3, was also evaluated. A rat oral LD50 was determined to be the most preferred source and it was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (2060 mg/kg)
This review generated TEELs which are more conservative that those in Rev. 29A. Previously, ERPG limits for acetic acid (CAS: 64-19-7) were used for TEEL development (note: incorrect units listed, ERPGs in ppm, not mg/m3). Considering this, and the health hazards associated with an HHR=3, the currently recommended basis (animal toxicity data) is more suitable for TEEL development in this case.
References
National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 77929, Methyltriacetoxysilane. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Methyltriacetoxysilane
https://www.osha.gov/chemicaldata/469
Thermo Fisher SDS, searchable by CASRN: https://www.thermofisher.com/us/en/home.html
https://www.silicone-solutions.co.uk/wp-content/uploads/2018/04/IS5628E-MSDS.pdf
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PAC values marked with a subscript "A" correspond to 60-minute AEGL values.
PAC values marked with a subscript "E" correspond to ERPG values.
PAC values marked by * are >= 10% lower explosive limit (LEL) but < 50% LEL.
PAC values marked by ** are > 50% LEL but < 100% LEL.
PAC values marked by *** are >= LEL.