4,4'-Methylenebis(2-chloroaniline)

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]

4,4′-Methylenebis(2-chloroaniline)
Names
Preferred IUPAC name
4,4′-Methylenebis(2-chloroaniline)
Other names
  • 4,4′-Methylene-bis(2-chloroaniline)
  • Cyanaset
  • Quodorole
  • Dacpm
  • Curalin M
  • Diamet Kh
  • Millionate M
  • Bis amine
  • MOCA
  • Bisamine S
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.002.654 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C13H12Cl2N2/c14-10-6-8(1-3-12(10)16)5-9-2-4-13(17)11(15)7-9/h1-4,6-7H,5,16-17H2 checkY
    Key: IBOFVQJTBBUKMU-UHFFFAOYSA-N checkY
  • InChI=1/C13H12Cl2N2/c14-10-6-8(1-3-12(10)16)5-9-2-4-13(17)11(15)7-9/h1-4,6-7H,5,16-17H2
    Key: IBOFVQJTBBUKMU-UHFFFAOYAI
  • Clc1cc(ccc1N)Cc2ccc(N)c(Cl)c2
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
potential occupational carcinogen[1]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Flash point 203 °C (397 °F; 476 K)
NIOSH (US health exposure limits):
PEL (Permissible)
none[1]
REL (Recommended)
Ca TWA 0.003 mg/m3 [skin][1]
IDLH (Immediate danger)
Ca [N.D.][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

It is a weak base with a slight odor and is reactive to active metals such as sodium, potassium, magnesium and zinc.[1]

Toxicity

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Employee 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

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In 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

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  1. ^ 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).
  2. ^ "4,4'-Methylenebis(2-chloroaniline)". TCI Chemicals. Retrieved March 17, 2014.
  3. ^ RTK HSFS 1250
  4. ^ 4,4'-Methylene bis (2-chloroaniline) Health Guideline, Occupational Safety and Health Administration
  5. ^ "EPA Begins Process to Prioritize Five Chemicals for Risk Evaluation Under Toxic Substances Control Act". US EPA. December 14, 2023. Retrieved 8 February 2024.