PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Methyl-1-propen-1-one, 2-; (Dimethylketene) | 598-26-5 |
18.00
4.00
3.00
|
||||||||||
| Formula | Synonyms | |||||||||||
| C4H6O | ||||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 70.09 | L | -97.5 | 34 |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.0057 | 0.063 | 0.19 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.016 | 0.18 | 0.54 |
Technical Basis
A review of available sources did not identify sources for dimethylketene. Instead, a similar chemical, ketene (C2H2O, CASRN: 463-51-4), was evaluated for TEEL development (Section 3.4.6). Analysts identified exposure guideline limits (i.e., TWA, STEL, AEGL, IDLH) and mouse inhalation toxicity data for ketene. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The ketene AEGL-3 and AEGL-2 were selected as the TEEL-3 and TEEL-2, respectively. TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = AEGL-2 (ketene, CASRN: 463-51-4)
• TEEL-3 = AEGL-3 (ketene, CASRN: 463-51-4)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse LC50, which was not found during this review. Instead, exposure limits for a similar chemical (ketene, CASRN: 463-51-4) were selected for TEEL-3 and TEEL-2 values. The Rev. 29A and current TEEL-1 methodology are consistent, with differences due to the change in TEEL-2. Resultant TEEL values are more conservative.
• TEEL-1 = TEEL-2/11
• TEEL-2 = AEGL-2 (ketene, CASRN: 463-51-4)
• TEEL-3 = AEGL-3 (ketene, CASRN: 463-51-4)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse LC50, which was not found during this review. Instead, exposure limits for a similar chemical (ketene, CASRN: 463-51-4) were selected for TEEL-3 and TEEL-2 values. The Rev. 29A and current TEEL-1 methodology are consistent, with differences due to the change in TEEL-2. Resultant TEEL values are more conservative.
References
Chemical information: https://comptox.epa.gov/dashboard/chemical/properties/DTXSID10208530
Ketene information: https://pubchem.ncbi.nlm.nih.gov/compound/10038
Ketene AEGL: https://www.epa.gov/aegl/ketene-results-aegl-program