ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
It has long been known that certain aromatic diisocyanates exhibit unequal reactivities of the two isocyanate groups. However, the degree of unsymmetry of reactivity in the previously known diisocyanates is limited. In this research, a number of structurally unsymmetrical diisocyanates were screened for unsymmetry of reactivity by reacting the diisocyanate with excess isoamyl alcohol in chlorobenzene solvent. The reaction was followed by observing the decrease of infrared absorption of the solution at 4.5 μ. A number of diisocyanates were found to have desirably high degrees of unsymmetry in reactivity. These diisocyanates, and the ratio of apparent half-lives of reaction for the two isocyanate groups are: 2,6-diethyl-p-phenylenediisocyanate, 100; 2,6-dimethyl-p-phenylenediisocyanate, 80; 2-bromo, 6-methyl-p-phenylenediisocyanate, 50; 2,6-dichloro-p-phenylenediisocyanate, 30; and 3,5-diethyl-4-4′-diisocyanato-diphenylmethane (DEMDI), 49.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1964.070080137
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