ISSN:
0947-6539
Keywords:
disproportionations
;
dithiocarba-mate
;
homogeneous catalysis
;
vulcanization
;
zinc
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Model studies have shown that cross-link precursors, that is, intermediates in the sulfur vulcanization of rubber, are transformed into cross-links by a nonsymmetric but regioselective disproportionation mechanism. Thus, two equivalents of the crosslink precursor of the type R—S—S—X are transformed into X—S—X and the actual cross-link R—S—S—S—R. Exchange of sulfur atoms is a prerequisite. A mechanism involving an SNi′ reaction with an allylic moiety, suggested in the literature, has not been observed. The disproportionation reaction is catalyzed by rubber-soluble zinc-dithiocarbamate complexes, an important class of vulcanization accelerators. By virtue of ligand-functional-group exchange reactions these complexes serve to transport and exchange sulfur atoms.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19970031117
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