The Lability of Sulfur Atoms in Vulcanization

1960 ◽  
Vol 33 (4) ◽  
pp. 1010-1014
Author(s):  
G. A. Blokh

Abstract The application of the isotope method to the investigation of the mechanism of the action of accelerator and vulcanizing agents has made it possible to look at this question in quite a new light. With the help of the isotope S it has been demonstrated that in the process of curing there takes place a continuous exchange of atoms of sulfur in the structure of the accelerators, and of elementary sulfur as a vulcanizing agent, with the formation of unstable intermediate compounds. The sulfur thus liberated undoubtedly has high energy, as a result of which it combines rapidly with the rubber. It must be remembered in this connection that the reacting elementary sulfur is an eight-membered S8 ring, while the sulfur liberated from the sulfur containing compounds has the open chain structure:

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 367
Author(s):  
Martyna Murat ◽  
Zahra Gholami ◽  
Josef Šimek ◽  
Daily Rodríguez-Padrón ◽  
José Miguel Hidalgo-Herrador

A great emphasis is placed on searching for efficient sources to produce renewable fuels due to the actual trends in avoiding the use of fossil resources to mitigate the environment’s deterioration. Thus, the use of waste from the food or wood industry for the production of biofuels is widely researched and may contribute to sustainable general development. Rendered fat and Fischer-Tropsch waxes are high-energy materials which could be used for the pyrolysis reaction. Therefore, in this study, the effect of reaction parameters and feedstock composition on the distribution of the pyrolysis products has been examined. The experiments were carried out in a nitrogen atmosphere in a multi-shot pyrolizer instrument equipped with GC-FID. First, the influence of the temperature was examined at 785, 800, and 815 °C. The highest yield to olefins was observed at 815 °C. The effect of triglycerides and paraffins contents (0–100% with 10% ramp) in the feedstock on the product composition was investigated at 815 °C. The gas chromatography analyses revealed that the feedstock composition did not significantly affect the product composition due to the high temperature and the long linear chain structure similarities between the free fatty acids and Fischer-Tropsch waxes.


Author(s):  
Aleksandar Bojkovic ◽  
Thomas Dijkmans ◽  
Hang Dao Thi ◽  
Marko Djokic ◽  
Kevin M. Van Geem

2019 ◽  
Vol 17 (2) ◽  
pp. 499-508 ◽  
Author(s):  
Galina S. Pevneva ◽  
Natalya G. Voronetskaya ◽  
Nikita N. Sviridenko ◽  
Anatoly K. Golovko

AbstractThe paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide–nickel–chromium (WC/Ni–Cr) catalytic additive and without it. The cracking is carried out in an autoclave at 500 °C for 30 min. The addition of the WC/Ni–Cr additive promotes the deepening of reactions of destruction not only of resins and asphaltenes, but also high molecular weight naphthene-aromatic compounds of the atmospheric residue. It is shown that the content of low molecular weight C9–C17 n-alkanes and C9–C10 alkylbenzenes rose sharply in the products of cracking with addition of WC/Ni–Cr in comparison with those produced without the additive. Alkyl- and naphthene-substituted aromatic hydrocarbons of benzene, naphthalene, phenanthrene series, polyarenes, benzo- and dibenzothiophenes are identified.


1980 ◽  
Vol 11 (3) ◽  
pp. 208-210
Author(s):  
E. P. Ovchinnikova ◽  
L. S. Abramova ◽  
Z. A. Rogovin

Author(s):  
Yamato Miyazawa ◽  
Kenji Kawaguchi ◽  
Ryo Katsuta ◽  
Tomoo Nukada ◽  
Ken Ishigami

ABSTRACT DAMASCENOLIDETM [1, 4-(4-methylpent-3-en-1-yl)furan-2(5H)-one], which is isolated from damask rose, is a useful aroma compound with a citrus-like odor. We have previously reported on the synthesis and odor properties of 34 analogs of 1 as part of our new aroma compound development project. In order to develop better aroma compounds and to gather more information on structure-odor relationships, six novel sulfur-containing analogs of 1 were synthesized. Odor evaluation revealed that their odors differed significantly from those of the corresponding sulfur-free compounds. The introduction of a sulfur atom does not necessarily result in a sulfur-like odor. In particular, the 2(5H)-thiophenone analogs gave waxy, oily and lactone-like odors that are uncharacteristic of sulfur-containing compounds. In many synthesized analogs, the introduction of a sulfur atom led to an increase in odor intensity, as expected.


1992 ◽  
Vol 18 (2) ◽  
pp. 181-188
Author(s):  
MARK M. JONES ◽  
MARK A. BASINGER ◽  
MYRON A. HOLSCHER

1988 ◽  
Vol 19 (6) ◽  
pp. 373-378 ◽  
Author(s):  
I. G. Shimko ◽  
V. A. Spasov ◽  
S. K. Chinennaya ◽  
R. I. Zakirova ◽  
I. N. Tananina ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document