Technology Type

Type: MDA Phosgenation
Process: Phosgenation
Abbreviation
: The late 1950s witnessed the emergence of the polymeric isocyanate PMDI based on the condensation of Aniline with Formaldehyde to form MDA, with the subsequent Condensation step with Phosgene also producing Isocyanate Oligomers. This PMDI product was introduced by the Carwin Co. (later Upjohn and Dow) in 1960 under the trade name PAPI. Similar products were introduced by Bayer and ICI in Europe. The superior Heat Resistance of Rigid Foams derived from pMDI prompted its exclusive use in Rigid Polyurethane Foams. The Oligomers of MDI actually have more commercial use than the Monomer and make it very difficult to treat MDI as a single entity as generally is the case with TDI. Industrially, 1 kg of MDI is produced from 0.8 kg of Aniline and 0.9 kg of Phosgene producing 0.6 kg of waste HCl.
Link: https://ebrary.net/14342/environment/production