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The kinetics of dissociation of blocked 2,4‐diisocyanatotoluene (tdi) in amines
Author(s) -
Kamath Prathima,
Srinivasan M.
Publication year - 1993
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4990320107
Subject(s) - chemistry , thiophenol , phenol , triethylamine , dissociation (chemistry) , kinetics , resorcinol , fourier transform infrared spectroscopy , cyclohexanone , reaction rate constant , solvent , benzenesulfonic acid , organic chemistry , catalysis , physics , quantum mechanics
Abstract The kinetics of dissociation of blocked diisocyanates based on commercial diisocyanatotoluene (TDI) (80/20 mixture of 2,4‐ and 2,6‐ isomers) in the presence of amino compounds was studied by a volumetric method and Fourier Transform IR (FTIR) spectral data. Second‐order rate constants for the dissociation of TDI adducts (with phenol, thiophenol and p ‐chlorophenol) in the presence of amines (dibenzyl, benzyl, cyclohexyl, n ‐hexyl and di‐ n ‐butyl) in cyclohexanone solvent are reported. The relative effects of various blocking agents, basicity of the amines and temperature on the dissociation of blocked TDI have been determined. An FTIR spectroscopic method was used to study the dissociation of blocked TDI (with blocking agents such as phenol, thiophenol, p ‐chlorophenol, p ‐nitrophenol, p ‐cresol, α‐naphthol and resorcinol) in the presence of excess triethylamine and in cyclohexanone solvent. Pseudo‐first‐order rate constants were calculated from NCO concentrations as determined from FTIR spectra.