Mechanisms of Reactions of Sulfinic Acids. VI. The Mechanism of the Disulfide-Sulfinic Acid Reaction

1964 ◽  
Vol 86 (11) ◽  
pp. 2270-2278 ◽  
Author(s):  
John L. Kice ◽  
Eva H. Morkved
Keyword(s):  
Sulfinic Acid ◽  
Sulfinic Acids ◽  
Acid Reaction ◽  
Mechanisms Of Reactions

Accelerated Oxidations of Polyisoprene. II. Effects of Hydrazines, Sulfur Compounds, and Phenyl-β-Napthylamine in Solution

1968 ◽  
Vol 41 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Frank R. Mayo ◽  
J. Heller ◽  
R. L. Walrath ◽  
Katherine C. Irwin
Keyword(s):  
Sulfur Compounds ◽  
Oxygen Absorption ◽  
Sulfinic Acid ◽  
Induction Periods ◽  
Sustained Effects ◽  
Low Concentrations ◽  
Sulfinic Acids ◽  
High Concentrations ◽  
A Chain ◽  
Future Work

Abstract At concentrations of 0.1 to 1 mM, phenylhydrazine causes marked decrease in viscosity of polyisoprene solutions in a few minutes at 50° C (see section II). This effect requires the presence of oxygen but no preoxidation of the rubber. Two molecules of oxygen are absorbed and about one fifth to one tenth of a chain is cleaved per molecule of phenylhydrazine added. The reaction is essentially complete within 20 min. This fast reaction is not much affected by the presence of antioxidants but results in the formation of some material (possibly phenolic) which reduces the effectiveness of other prooxidants. 1,1 -Dimethylhydrazine and 1,2-diphenylhydrazine, unlike phenylhydrazine, have slow but sustained effects. Hydrazine monohydrate is intermediate in its action. Investigation of the effects of several sulfur compounds on polyisoprene solutions brought out some striking effects and a need for further work. p-Thiocresol is a strong prooxidant for our polyisoprene solutions at concentrations below 0.2 mM. At higher concentrations, induction periods occurred with some, but not all, samples and could be shortened by the addition of t-butyl hydroperoxide. Di-p-tolyl disulfide was somewhat less active, but its effect increased regularly with its concentration. Other aryl thiols and disulfides had similar activity but benzyl derivatives did not. At low concentrations, benzene sulfinic acid and p-toluene sulfinic acid are as strong prooxidants as the aryl thiols; at high concentrations they are more active but short lived. A few other sulfur compounds or combinations had no interesting prooxidant properties. In contrast to results on polyisoprene, aryl thiols and sulfinic acids had little effect in preliminary tests in promoting the oxidation of cyclopentene and methyl-cyclohexene. The effects of a common rubber antioxidant, phenyl-β-naphthylamine, alone and in combination with various prooxidants, were followed by oxygen absorption and viscosity changes. The effects are complex; there are indications of both catalytic and anticatalytic effects, and of both scission and crosslinking. The results are most useful in showing the potential of the method for future work on understanding and comparing effects of antioxidants.

The Mechanism of the Alkyl Sulfide—Sulfinic Acid Reaction. The Direction of Cleavage of Unsymmetrical Sulfides1a

1966 ◽  
Vol 31 (3) ◽  
pp. 848-852 ◽  
Author(s):  
John L. Kice ◽  
Bruce R. Toth ◽  
David C. Hampton ◽  
James F. Barbour
Keyword(s):  
Sulfinic Acid ◽  
Alkyl Sulfide ◽  
Acid Reaction
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