Health › Isocyanates › 2,4'-MDI

2,4'-MDI (Diphenylmethane-2,4'-Diisocyanate)CAS 5873-54-1

The minor structural isomer of MDI — typically a few percent of technical PMDI mixtures.

Other Isocyanates substances:Toluene DiisocyanatePure MDIPolymeric MDI4,4'-MDI HomopolymerMDIHexamethylene DiisocyanatePolymeric TDI
Building products and consumer items containing Isocyanates family members
2,4'-MDI belongs to the Isocyanates family — products shown above commonly contain one or more substances from this family

Toxic Chemical Databases

Substance-specific listings — these flags are for 2,4'-MDI alone, not for the broader family.

LBC Red List
Listed
Prop 65
Not Listed
IARC
Listed
NTP RoC
Listed
GSPI
Not Listed
REACH SVHC
Listed
TSCA
Listed

Chemical Type

Aromatic Diisocyanate — Asymmetric Isomer

Chemical Description

The 2,4'-isomer of MDI has one isocyanate group positioned ortho to the methylene bridge, giving it different reactivity than the symmetric 4,4'-isomer. Pure 2,4'-MDI is rarely used standalone but appears as a characterization marker for technical PMDI mixtures. Toxicologically it shares the MDI family's respiratory and skin sensitization profile.

Biological Activity

Severity scores specific to this substance, NOT the parent family average. Differences between siblings are real and meaningful.

Respiratory
9/10
Immune
8/10
Skin
7/10
Cancer
4/10
Reproductive
5/10
Developmental
5/10
Liver/Kidney
5/10
Neurological
3/10
Endocrine
3/10
Cardiovascular
3/10

Top Health Consequences

Pathways of Exposure

Building Materials with 2,4'-MDI

Listed alphabetically — product categories where this specific substance appears.

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