1. The rates of the following nucleophilic substitution reactions have been measured in benzene solution: (**1**) cyanuric chloride and aniline; (**2**) 2‐anilino‐3,5‐dichloro‐triazine and aniline; (**3**) 1‐N‐methylanilino‐3,5‐dichloro‐triazine and N‐methylaniline.
Über die Kinetik der Reaktion von Hexamethylendiisocyanat mit 2-ethyl-1,3-hexandiol in verschiedenen Lösungsmitteln
✍ Scribed by Hager, Wilhelm ;Ueberreiter, Kurt
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1979
- Weight
- 412 KB
- Volume
- 180
- Category
- Article
- ISSN
- 0025-116X
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✦ Synopsis
Abstract
The kinetics of the polyaddition reaction of hexamethylenediisocyanate with 2‐ethyl‐1,3‐hexanediol were investigated in various aprotic solvents with zero dipole moment. The reactions were followed by means of IR‐spectroscopy. The reaction is of 2nd order. Rate constants depend on the dielectric constants of solvents. Energy of activation does not depend on the nature of the solvent, its value for the first isocyanate group is 28,97 kJ/mol and 17,79 kJ/mol for the second one. It is surprising that the consecutive reaction of the second isocyanate group is faster than that of the first one, if the diol is 2‐ethyl‐1,3‐hexanediol. This has not been found before. It could be shown that in the addition reaction of the same isocyanate with 2‐methyl‐2,4‐pentanediol the reactivity of the second isocyanate group is much smaller than that of the first one, as has been found with other dioles investigated until now.
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