PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Isobutyric acid | 79-31-2 | 2529 |
11.01
14.01
14.02
4.07
4.08
|
|||||||||
| Formula | Synonyms | |||||||||||
| C4H8O2 | ISOBUTYRIC ACID, 2-METHYLPROPANOIC ACID, 2-METHYLPROPIONIC ACID, ACIDE ISOBUTYRIQUE (DOT FRENCH), ACIDO ISOBUTÍRICO (DOT SPANISH), ALPHA-METHYLPROPANOIC ACID, ALPHA-METHYLPROPIONIC ACID, DIMETHYLACETIC ACID, I-BUTYRIC ACID, ISO-BUTYRIC ACID, ISOBUTANOIC ACID, ISOPROPYLFORMIC ACID, PROPANE-2-CARBOXYLIC ACID | |||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 88.12 | L | -47 | 1 | 14.7 | 0.949 @ 20°C | 20000 |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.80 | 8.8 | 53 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 0.22 | 2.4 | 15 |
Technical Basis
A review of available sources identified the following: rabbit and rat LD50 acute toxicity data. 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 most preferred route and species, the rat oral LD¬50, was selected as the TEEL-3 basis. The density of this substance is 0.95 g/cm3 at 20°C, resulting in a dose equivalent to 266 mg/kg. 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 (280 uL/kg= 266 mg/kg, density = 0.95 g/cm3)
This review generated TEEL values that are inconsistent with Rev. 29A. The Rev. 29A and current TEEL-3 bases are both rat oral LD50; however, the previous dose was not found during the review. The Rev. 29A and current TEEL-2 and TEEL-1 values were derived using the same methodology, with differences due to the change in TEEL-3.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (280 uL/kg= 266 mg/kg, density = 0.95 g/cm3)
This review generated TEEL values that are inconsistent with Rev. 29A. The Rev. 29A and current TEEL-3 bases are both rat oral LD50; however, the previous dose was not found during the review. The Rev. 29A and current TEEL-2 and TEEL-1 values were derived using the same methodology, with differences due to the change in TEEL-3.
References
American Industrial Hygiene Association Journal., 23(95), 1962 [PMID:13914538]. Retrieved from: https://pubchem.ncbi.nlm.nih.gov/compound/Isobutyric-acid