Diisocyanates
| Diisocyanate monomers (selection) |
 General structure of a diisocyanate. The isocyanate groups are marked in blue , R is a double-bonded organic radical (e.g. a para - phenylene group ). |
 Hexamethylene-1,6-diisocyanate (HDI) |
 Toluene-2,4-diisocyanate (TDI) |
 Diphenylmethane-4,4'-diisocyanate (MDI) |
 Isophorone diisocyanate (IPDI) |
In chemistry, diisocyanates are substances that contain two isocyanate groups. They are technically important raw materials for the production of polyurethanes (e.g. " construction foam ") and polyureas .
Manufacturing
Diisocyanates are produced from diamines by reaction with phosgene (COCl 2 ):
The course of the reaction corresponds to the reaction of primary amines with phosgene.
use
To produce polyurethanes, diisocyanates are reacted with diols (e.g. ethylene glycol ):
If the polyaddition for polyurethane production is carried out in the presence of a small amount of water, the hydrolysis of isocyanate also produces some CO 2 . The carbon dioxide escapes and the polyurethane is inflated. This creates a polyurethane foam that is used as upholstery (furniture, motor vehicles). Polyurethanes belong to the group of polyadducts and are also widely used in other branches of industry and in construction.
Individual evidence
- ^ Otto-Albrecht Neumüller (editor): Römpps Chemie Lexikon , 8th edition, Frank'sche Verlagshandlung, Stuttgart 1983, ISBN 3-440-04513-7 , p. 926.
- ↑ Joachim Buddrus, Bernd Schmidt: Basics of Organic Chemistry , 5th edition, de Gruyter Verlag, Berlin 2015, ISBN 978-3-11-030559-3 , pp. 682–683.
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindindustrie, Leipzig 1985, ISBN 3-342-00280-8 , p. 738.
- ^ MD Lechner, K. Gehrke and EH Nordmeier: Makromolekulare Chemie , 4th edition, Birkhäuser Verlag, 2010, ISBN 978-3-7643-8890-4 , pp. 136-138.