), Back Directory. [msds information] 1,1′-Methylenebis(4-isocyanatobenzene)( ).msds. Page 1. Page 2. •. •. •. ³. ³. ³. Page 3. ³. Page 4. ³. ³. ³. ³. ³. ³. ³. ³. ³. ³. Page 5. ≥. ≥. Page 6. METHYLENE BISPHENYL. ISOCYANATE. DOT Number: UN DOT Hazard Class: (Poison). NAERG Code: CAS Number: Hazard rating.
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Methylene diphenyl diisocyanatemost often abbreviated as MDI, is an aromatic di isocyanate.
Three isomers are common, varying by the positions of the isocyanate groups around the rings: The 4,4′ isomer is most widely used, and is also known as 4,4′-diphenylmethane diisocyanate. MDI reacts with polyols in the manufacture of polyurethane.
Methylene diphenyl diisocyanate
It is the most produced diisocyanate, accounting for The largest producer is Wanhua Group followed closely by Covestro. The first step of the production of MDI is the reaction of aniline and formaldehydeusing hydrochloric acid msvs a catalyst to produce a mixture of diamine precursors, as well as their corresponding polyamines:.
Then, these diamines are treated with phosgene to form a mixture of isocyanates, the isomer ratio being determined by the isomeric composition of the diamine. Distillation of the mixture gives a mixture of oligomeric polyisocyanates, known as polymeric MDIand a mixture of MDI isomers which has a low 2,4′ isomer content. Further purification entails fractionation of the MDI isomer mixture. The positions of the isocyanate groups influences their reactivity.
In 4,4′-MDI, the two isocyanate groups are equivalent but in 2,4′-MDI the two groups display highly differing msfs. The group at the 4-position is approximately four times more reactive than the group at the 2-position due to steric hindrance.
The major application of 4,4′-MDI is the production of rigid polyurethane.
Methylene bisphenyl isocyanate
Typical polyols used are polyethylene adipate a polyester and poly tetramethylene ether glycol a polyether. MDI is the least hazardous of the commonly available isocyanates but is not benign. However, it, like the other isocyanates, is an allergen and sensitizer.
Persons developing sensitivity to isocyanates may have dangerous systemic reactions to extremely small exposures, including respiratory failure. Handling MDI requires strict engineering controls and personal protective equipment.
It is a potentially violently reactive material towards water and other nucleophiles. From Wikipedia, the free encyclopedia.
CDC – NIOSH Pocket Guide to Chemical Hazards – Methylene bisphenyl isocyanate
Bis 4-isocyanatophenyl methane 1-Isocyanato[ 4-isocyanatophenyl methyl]benzene 4,4′-Methylene diphenyl diisocyanate 4,4′-Diphenylmethane diisocyanate Bayer Desmodur 44 Methylene bis 4-phenyl isocyanate Pure MDI. Interactive image Interactive image. LD 50 median dose. LD Lo lowest published.
4,4′-Methylenediphenyldiisocyanate | C15H10N2O2 – PubChem
LC 50 median concentration. Toluene diisocyanate Naphthalene diisocyanate Hexamethylene diisocyanate Isophorone diisocyanate. Eco-Profiles of the European Plastics Industry. Archived from the original PDF on Safety, Health and the Environment: A Source Book and Practical Guide. Retrieved from ” https: Views Read Edit View history.
Lethal dose or concentration LDLC:.