PAC Database - Detailed Chemical Data
Chemical Identity
| Chemical | CAS# | UN# | Health Code Numbers | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Isobutyric anhydride; (2-Methylpropionic anhydride) | 97-72-3 | 2530 |
11.01
14.01
14.02
3.11
|
|||||||||
| Formula | Synonyms | |||||||||||
| C8.H14.O3 | ISOBUTYRIC ANHYDRIDE, 2-METHYLPROPANOIC ANHYDRIDE, 2-METHYLPROPIONIC ANHYDRIDE, ANHÍDRIDO ISOBUTÍRICO (DOT SPANISH), ANHYDRIDE ISOBUTYRIQUE (DOT FRENCH), ISOBUTANOIC ANHYDRIDE, ISOBUTYRIC ACID ANHYDRIDE, ISOBUTYRYL ANHYDRIDE | |||||||||||
Physical Properties
| Mol Wt | State | MP (°C) | BP (°C) | VP (Hg) | VP (°C) | SG | LEL (ppm) |
|---|---|---|---|---|---|---|---|
| 158.22 | L | -53.5 | 0.9535 @ 20°C | 10000 |
PAC Values
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 6.7 | 74 | 440 |
| PAC-1 | PAC-2 | PAC-3 |
|---|---|---|
| 1.0 | 11 | 68 |
Technical Basis
Data is limited for isobutyric anhydride. Sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were evaluated using factors in Tables 3.2, 3.3, and 3.4. In a ThermoFisher Scientific safety data sheet (SDS) (revised 24-Dec-2021), a rat oral LD50 of 2230 mg/kg is listed. As the original source for this toxicity is unknown, similar structures/components of isobutyric anhydride, such as propionic acid (CAS: 79-09-4) were explored for comparison. The potential TEEL-3 results are as follows:
TEEL-3 = 440 mg/m3 (isobutyric anhydride rat oral LD50)
TEEL-3 = 230 mg/m3 (MW-adjusted propionic rat 240-min LC50)
TEEL-3 = 550 mg/m3 (MW-adjusted propionic rat oral LD50)
As these results are comparable, the isobutyric anhydride rat oral LD50 was determined to be an appropriate starting point for TEEL-3 development. TEEL-2 and TEEL-1 were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (2230 mg/kg)
This review generated less conservative TEEL values than those in Rev. 29A. In Rev. 29A, the TEEL-3 basis was an assumed HHR=3; the current basis is a toxicity exposure for the chemical of interest, which is preferable (LD50 > HHR).
TEEL-3 = 440 mg/m3 (isobutyric anhydride rat oral LD50)
TEEL-3 = 230 mg/m3 (MW-adjusted propionic rat 240-min LC50)
TEEL-3 = 550 mg/m3 (MW-adjusted propionic rat oral LD50)
As these results are comparable, the isobutyric anhydride rat oral LD50 was determined to be an appropriate starting point for TEEL-3 development. TEEL-2 and TEEL-1 were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (2230 mg/kg)
This review generated less conservative TEEL values than those in Rev. 29A. In Rev. 29A, the TEEL-3 basis was an assumed HHR=3; the current basis is a toxicity exposure for the chemical of interest, which is preferable (LD50 > HHR).
References
https://cameochemicals.noaa.gov/chemical/940
National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 7346, Isobutyric anhydride. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Isobutyric-anhydride.
Fisher Scientific SDS for Isobutyric anhydride: https://www.fishersci.com/store/msds?partNumber=AC257785000&productDescription=ISOBUTYRIC+ANHYDRIDE+97+500GR&vendorId=VN00032119&countryCode=US&language=en
https://echa.europa.eu/de/registration-dossier/-/registered-dossier/13208/7/3/2
Propionic acid Toxicity; via RTECs https://www.cdc.gov/niosh-rtecs/UE5ACA30.html