[article]
| Titre : |
The selectivity of isophorone diisocyanate in the urethane reaction : Influence of temperature, catalysis and reaction partners |
| Type de document : |
texte imprimé |
| Auteurs : |
R. Lomoelder, Auteur ; F. Plogmann, Auteur ; P. Speier, Auteur |
| Année de publication : |
1998 |
| Article en page(s) : |
p. 31-38 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Tags : |
'Polyuréthane' 'Diisocyanate organique' 'Cyclohexane dérivé' Polyaddition Diol 'Réaction catalytique' modèle' 'Activité 'Sélectivité catalyseur' Régiosélectivité 'Acide Lewis' 'Métal Composé' 'Base 'Amine tertiaire' 'Effet température' 'Etude expérimentale' comparative' |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The selectivity of isophorone diisocyanate (IPDI) in the urethane reaction demonstrates a strong dependence on temperature, catalyst type, and degrees of substitution of the reaction partner. It was possible to establish, by means of GC analysis of the monomer content, that dibutyltin dilaurate (DBTL) leads to the highest selectivity compared to the series of Sn, Zn, Bi, Fe, and amine catalysts. The ratio ofthe rate constant Γin the model reaction with 1-butanol at 20°C was increased from 5.5 in the uncatalyzed variant to 11.5 by catalysis with DBTL. The use of diazabicyclooctane succeeded in reversing the selectivity. The selectivity under DBTL catalysis dropped from 11.5 at 20°C to 6.5 at 100°C. The use of 2-butanol leads to a further increase in selectivity: Γ= 17 with DBTL catalysis at 20°C. By the resolution of all four monourethanes by GC analysis of the 1-butanol reaction, a significantly higher selectivity of trans IPDI was established: the ratio of secondary monourethane to primary monourethane with trans IPDI is higher by a factor of 2. A very good correlation between prepolymer synthesis and the model reactions was observed. Recommended optimal conditions for prepolymer synthesis based on IPDI are temperatures between 40°C to 60°C using DBTL catalysis. |
| Note de contenu : |
- Selectivity of IPDI by application of various urethane catalysts
- Influence of temperature on the selectivity of IPDI - Additional steric hindrance : 2-butanol - Back to the pratical : NCO prepolymers |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13179 |
in PAINTINDIA > Vol. XLVIII, N° 11 (11/1998) . - p. 31-38
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