The Reaction of Sulfur and Sulfur Compounds with Olefinic Substances. V. Rubber Vulcanization

1948 ◽  
Vol 21 (3) ◽  
pp. 543-552
Author(s):  
G. F. Bloomfield
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Double Bond ◽  
Sulfur Atom ◽  
Small Proportion ◽  
Sulfur Compounds ◽  
Cross Linking ◽  
Inhibiting Effect ◽  
Mercapto Groups ◽  
Soluble Zinc

Abstract Data presented for a range of vulcanized rubbers prepared under different conditions show that, while olefinic unsaturation becomes reduced by vulcanization in the proportion of one double bond for each sulfur atom combined with a C5H8 unit, the original H/C ratio of 8/5 is not altered. The loss of unsaturation is somewhat modified when zinc oxide or certain accelerators also are present. Oxygen has a slight inhibiting effect on vulcanization; hydrogen sulfide and thiols markedly catalyse the vulcanization reaction without, apparently, affecting the efficiency of the sulfur cross-linking reaction. In confirmation of the results of Hull, Olsen, and France, a small proportion of zinc oxide or a soluble zinc soap promotes a reaction between sulfur and mercapto groups whereby di- and polysulfides are formed with liberation of hydrogen sulfide. The same type of activity is shown by some of the nitrogenous accelerators commonly used in rubber vulcanization. Substantial conversion of mercapto groups into polysulfide linkages is, therefore, to be expected when vulcanization is conducted in the presence of these auxiliary substances.

The Interaction of Sulfur and Sulfur Compounds with Olefinic Substances. VII. Low-Temperature Sulfuration of Trialkylethylenes with Hydrogen Sulfide-Sulfur Dioxide and with a Sulfur-Zinc Dithiocarbamate System

1955 ◽  
Vol 28 (2) ◽  
pp. 470-479
Author(s):  
E. H. Farmer ◽  
J. F. Ford ◽  
J. A. Lyons
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Low Temperature ◽  
Room Temperature ◽  
Cross Linking ◽  
Sulfide Sulfur ◽  
Tetramethylthiuram Disulfide ◽  
Zinc Compounds ◽  
Low Concentrations

Abstract The sulfuration of trialkylethylenes with hydrogen sulfide-sulfur dioxide at 0° C (Peachey process) results in disubstitutive cross-linking of the olefins, yielding dialkenyl tetrasulfides. At higher temperatures, substitutive-additive cross-linking occurs, and alkyl alkenyl polysulfides are formed. Dialkenyl tetrasulfides are similarly formed by causing the olefin to react with sulfur at room temperature in the presence of zinc oxide and zinc dibutyldithiocarbamate, low concentrations of hydrogen sulfide acting as a catalyst for this reaction. At higher temperatures, the reaction is also exclusively disubstitutive, a feature connected with the function of zinc compounds in influencing the cross-linking reaction. The sulfuration of olefins with tetramethylthiuram disulfide at 140° C shows a similar influence of zinc compounds.

The Nature of Vulcanization Part IV

1929 ◽  
Vol 2 (3) ◽  
pp. 421-430
Author(s):  
H. P. Stevens ◽  
W. H. Stevens
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Hydrochloric Acid ◽  
Zinc Sulfide ◽  
Low Temperatures ◽  
Sulfur Compounds ◽  
Zinc Salt ◽  
Acetone Vapor ◽  
Volatile Sulfur Compounds ◽  
Ether Mixture

Abstract (1) At low temperatures by means of accelerators it is possible to produce vulcanites containing “combined sulfur” considerably in excess of that required for the formula C5H8S. Such vulcanites may be obtained by vulcanizing at 100° with a variety of ultra-accelerators with and without zinc oxide as an activator. If zinc oxide or a zinc salt is used the excess coefficient cannot be explained by the presence of the zinc sulfide in the vulcanite. (2) The amount of sulfur combined with the rubber, given sufficient heating and presence of accelerator, is mainly dependent on the excess of sulfur present. (3) Extraction of the vulcanite with hydrochloric acid-ether mixture removes a part of the “combined” sulfur. A considerable amount is removed when the amount of combined sulfur is very large, but even then the amount of sulfur remaining is considerably in excess of that required by the formula C5H8S. (4) Vulcanization at low temperatures in solution in accordance with Whitby's procedure with the aid of accelerators also yields vulcanites with coefficients in excess of that required for the formula C5H8S. (5) The result of vulcanization at low temperatures is approximately the same, whether the rubber contains all the protein and serum ingredients, the usual proportion, or very little. (6) Extraction of sulfur from vulcanite with hot acetone vapor is not complete after 1210 hrs. (7) Having regard to the hydrogen sulfide and other volatile sulfur compounds evolved in appreciable quantities during vulcanization, it is evident that part of the combined sulfur results from substitution of hydrogen by sulfur. This substituted product is decomposed by the hydrochloric acid-ether mixture. It may not be possible to decompose the whole in this manner. Consequently, any “combined” sulfur in excess of that required by the formula C5H8S may result from substitution in the molecule.

Rubber, Polyisoprenes and Allied Compounds. VIII. The Formation of Dialkyl Sulfide Dihalides, and Its Bearing on the Problem of Determining the Unsaturation of Vulcanized Rubber

1946 ◽  
Vol 19 (2) ◽  
pp. 287-295
Author(s):  
George F. Bloomfield
Keyword(s):  
Zinc Oxide ◽  
Acetic Acid ◽  
Double Bond ◽  
Potassium Iodide ◽  
Sulfur Atom ◽  
Iodine Monochloride ◽  
Vulcanized Rubber ◽  
Dialkyl Sulfide ◽  
Dialkyl Sulfides ◽  
Halogen Acid

Abstract In determining the unsaturation of olefinic sulfides and disulfides by halogenation methods, the addition of halogen to the sulfur atom must be taken into account. The dihalides of dialkyl or dialkenyl sulfides react with aqueous potassium iodide partly to liberate iodine with regeneration of the sulfide, and partly to form halogen acid and dialkyl or dialkenyl sulfoxides. Correction for the latter reaction, which occurs extensively in the presence of alcohol or acetic acid, must be applied before reliable unsaturation values for dialkenyl sulfides can be obtained. With vulcanized rubber and iodine monochloride, the precise magnitude of the correction to be applied is uncertain, but this uncertainty can be removed by using bromine as the additive reagent. Simple rubber-sulfur vulcanizates show a loss of unsaturation corresponding to one double bond per sulfur atom combined up to at least 8 per cent of combined sulfur; vulcanizates accelerated with mercaptobenzothiazole in the presence of zinc oxide exhibit a substantially smaller loss of unsaturation. The dibromides of dialkyl sulfides readily yield a molecule of bromine to olefins, the reaction being practically exclusively additive.

Sulfur Linkage in Vulcanized Rubbers. I. Reaction of Methyl Iodide with Sulfur Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 303-330
Author(s):  
M. L. Selker ◽  
A. R. Kemp
Keyword(s):  
Double Bond ◽  
Methyl Iodide ◽  
Sulfur Atom ◽  
Direct Evidence ◽  
Chemical Nature ◽  
Sulfur Compounds ◽  
Double Bonds ◽  
The One ◽  
Direct Attack

Abstract For many years the rubber chemist, in trying to explain the chemical nature of the vulcanization of rubber, was limited by two accepted theories: (1) Sulfur adds at the double bonds of the hydrocarbon, and (2) one atom of sulfur combines for each double bond saturated in the reaction. Therefore it was concluded that only one type of sulfur linkage would occur in vulcanizates. However, it was impossible on this basis to propose a hypothesis to account for all the facts. The few bits of direct evidence available have semed to support the theory of “one sulfur for each double bond saturated”. Since it is difficult to make any direct attack on this problem and since the art of vulcanization has far surpassed the science, it was not until 1938 that grave doubt was thrown on the generality of the “one sulfur atom per double bond saturated” theorem. The work of Brown and Hauser indicated that there were wide variations in the number of sulfur atoms combined for each double bond saturated, depending on the type of acceleration used. Four years later Thornhill and Smith pointed out that, in compounds containing reinforcing channel blacks, no loss of unsaturation could be detected on combination of sulfur during vulcanization. Thus the relation between sulfur combination and changes in unsaturation is at present obscure.

Nucleophilic Attack on Some Isothiazolium Salts

1973 ◽  
Vol 51 (18) ◽  
pp. 3081-3086 ◽  
Author(s):  
David M. Mckinnon ◽  
Mohamed E. Hassan
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Atom ◽  
Nucleophilic Attack ◽  
Isothiazolium Salts

A variety of isothiazolium salts has been prepared and allowed to react with sodium benzoylacetate. 2-Benzoylthiophenes are obtained, suggesting that the position of initial nucleophilic attack is at the sulfur atom of the heterocyclic cation. Reaction with hydrogen sulfide gave acyclic reduction products, or 1,2-dithiole derivatives, depending on the type of substituent on nitrogen in the isothiazolium salts.

In situ sulfur K-edge X-ray absorption spectroscopy of the reaction of zinc oxide with hydrogen sulfide

1996 ◽  
pp. 1431 ◽  
Author(s):  
John Evans ◽  
Judith M. Corker ◽  
Clive E. Hayter ◽  
Richard J. Oldman ◽  
B. Peter Williams
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Absorption Spectroscopy ◽  
X Ray ◽  
X Ray Absorption

Selective Colorimetric Detection of Hydrogen Sulfide Based on Primary Amine-Active Ester Cross-Linking of Gold Nanoparticles

2015 ◽  
Vol 87 (14) ◽  
pp. 7267-7273 ◽  
Author(s):  
Zhiqin Yuan ◽  
Fengniu Lu ◽  
Meihua Peng ◽  
Chia-Wei Wang ◽  
Yu-Ting Tseng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Sulfide ◽  
Primary Amine ◽  
Colorimetric Detection ◽  
Cross Linking ◽  
Active Ester
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