4,4′-Methylenebis(2-chloroaniline) (also known as MOCA, MBOCA, and bisamine) is a substance used as a curing agent in polyurethane production.[3] MOCA is an aromatic amine which is structurally similar to benzidine, a known human bladder carcinogen. MOCA has been shown to cause hepatomas in mice and rats, lung and mammary carcinomas in rats and bladder cancer in dogs. It is a proven human carcinogen standing on the WHO List of IARC Group 1 carcinogens, with a current threshold limit value of 0.01 ppm in the industrial atmosphere. Animal studies have resulted in tumor growth in the liver, lung, and bladder.[1]
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| Names | |
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| Preferred IUPAC name
4,4′-Methylenebis(2-chloroaniline) | |
Other names
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| Identifiers | |
3D model (JSmol)
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.002.654 |
| KEGG | |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C13H12Cl2N2 | |
| Molar mass | 267.15 g·mol−1 |
| Appearance | Tan-colored pellets or flakes[1] |
| Odor | faint, amine-like[1] |
| Density | 1.44 g/cm3[1] |
| Melting point | 104 to 109 °C (219 to 228 °F; 377 to 382 K)[2] |
| insoluble | |
| Vapor pressure | 0.00001 mmHg (20 °C)[1] |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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potential occupational carcinogen[1] |
| NFPA 704 (fire diamond) | |
| Flash point | 203 °C (397 °F; 476 K) |
| NIOSH (US health exposure limits): | |
PEL (Permissible)
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none[1] |
REL (Recommended)
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Ca TWA 0.003 mg/m3 [skin][1] |
IDLH (Immediate danger)
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Ca [N.D.][1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It is a weak base with a slight odor and is reactive to active metals such as sodium, potassium, magnesium and zinc.[1]
Toxicity
editEmployee exposure is often monitored by measurement of urinary MOCA in free and/or conjugated form.[4] The best currently available indicator of absorption of MOCA is urinary total MOCA estimations based on spot creatinine corrected urines. Although this method is not without limitations, that is unmetabolised MOCA is measured and dose-response curves are lacking, its use is a reasonable means of monitoring the effectiveness of engineering controls, personal protective equipment and work practices including education. MOCA levels are usually higher at the end of the shift and reflect exposure over the preceding two to three days. The biological half-life of MOCA in urine is approximately 23 hours.
Regulation
editIn December 2023, the US EPA announced that it was prioritizing MBOCA "for risk evaluation under the Toxic Substances Control Act (TSCA)" along with four other toxic chemicals.[5]
References
edit- ^ a b c d e f g h i j NIOSH Pocket Guide to Chemical Hazards. "#0411". National Institute for Occupational Safety and Health (NIOSH).
- ^ "4,4'-Methylenebis(2-chloroaniline)". TCI Chemicals. Retrieved March 17, 2014.
- ^ RTK HSFS 1250
- ^ 4,4'-Methylene bis (2-chloroaniline) Health Guideline, Occupational Safety and Health Administration
- ^ "EPA Begins Process to Prioritize Five Chemicals for Risk Evaluation Under Toxic Substances Control Act". US EPA. December 14, 2023. Retrieved 8 February 2024.