Chemistry of Sulfur-Olefin Reactions

Armstrong, Robert T.; Little, J. R.; Doak, Kenneth W.

doi:10.1021/ie50415a007

Cited by 38 publications

(16 citation statements)

References 9 publications

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“…Sulfur mainly interacts with the polymer on the allylic carbon [23]. Armstrong et al [66] already demonstrated, in 1944, using model compound vulcanization (MCV), that sulfide cross-links are attached to the polymer chains through α-methylene or α-methyl groups, and that allylic isomers are therefore possible. The MCV method relies on the use of low molecular weight alkenes or other unsaturated compounds for simulating the rubber reactivity undergoing the same reaction conditions [66].…”

Section: Vulcanization Mechanismmentioning

confidence: 99%

“…Armstrong et al [66] already demonstrated, in 1944, using model compound vulcanization (MCV), that sulfide cross-links are attached to the polymer chains through α-methylene or α-methyl groups, and that allylic isomers are therefore possible. The MCV method relies on the use of low molecular weight alkenes or other unsaturated compounds for simulating the rubber reactivity undergoing the same reaction conditions [66]. The MCV method has also been performed in most recent studies to extensively investigate the reaction mechanism [67][68][69][70][71] and different analytical and spectroscopic techniques have been employed to study the cross-link formation, such as mass spectrometry (MS), liquid chromatography coupled spectrometry (LC-MS), nuclear magnetic resonance (NMR), Raman, and Infrared (IR) spectroscopy [67,71].…”

Section: Vulcanization Mechanismmentioning

confidence: 99%

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Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

et al. 2019

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The efficiency of sulfur vulcanization reaction in rubber industry is generally improved thanks to the combined use of accelerators (as sulphenamides), activators (inorganic oxides), and co-activators (fatty acids). The interaction among these species is responsible for the formation of intermediate metal complexes, which are able to increase the reactivity of sulfur towards the polymer and to promote the chemical cross-links between the rubber chains. The high number of species and reactions that are involved contemporarily in the process hinders the complete understanding of its mechanism despite the long history of vulcanization. In this process, ZnO is considered to be the most efficient and major employed activator and zinc-based complexes that formed during the first steps of the reaction are recognized to play a main role in determining both the kinetic and the nature of the cross-linked products. However, the low affinity of ZnO towards the rubber entails its high consumption (3–5 parts per hundred, phr) to achieve a good distribution in the matrix, leading to a possible zinc leaching in the environment during the life cycle of rubber products (i.e., tires). Thanks to the recent recognition of ZnO ecotoxicity, especially towards the aquatic environment, these aspects gain a critical importance in view of the urgent need to reduce or possibly substitute the ZnO employed in rubber vulcanization. In this review, the reactivity of ZnO as curing activator and its role in the vulcanization mechanism are highlighted and deeply discussed. A complete overview of the recent strategies that have been proposed in the literature to improve the vulcanization efficiency by reducing the amount of zinc that is used in the process is also reported.

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Section: Vulcanization Mechanismmentioning

confidence: 99%

Section: Vulcanization Mechanismmentioning

confidence: 99%

Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

et al. 2019

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“…Penczek's work demonstrates that S 8 could be able to polymerize with propylene to prepare linear polysulfides . Armstrong reported that the reaction of S 8 and olefins usually afforded organic polysulfur−alkyl adduct (RS n R) . According to previous studies, S 8 rings attacked by vinyl groups could form organosulfur compounds regarded as the reaction pathways .…”

Section: Resultsmentioning

confidence: 99%

“…[ 32 ] Armstrong reported that the reaction of S 8 and olefi ns usually afforded organic polysulfur−alkyl adduct (RS n R). [ 33 ] According to previous studies, S 8 rings attacked by vinyl groups could form organosulfur compounds regarded as the reaction pathways. [ 34 ] The colorimetric analysis suggest that the fl uorescent species are organic RS n R, formed from the reaction between sulfur and ODE when heated at elevated temperatures (>150 °C).…”

Section: Resultsmentioning

confidence: 99%

Shape-Controlled Synthesis of High-Quality Cu₇S₄Nanocrystals for Efficient Light-Induced Water Evaporation

Zhang

Yan

Xue

et al. 2016

Small

160

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Copper sulfides (Cu S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu S NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu S NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu S NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%.

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“…Many of the reactions involving elemental sulfur occur by free radical mechanism [5][6][7][8], therefore in the first part of our work we studied the electrochemical oxidation and reduction of 6(7)-benzoylperimidines. Taking into account the high reactivity of radical ion intermediates in the synthesis of sulfur derivatives [9,10], we considered the possible cyclization of 1H-perimidine carbonyl derivatives with the participation of hydrogen sulfide under the conditions of radical ion initiation at room temperature.…”

mentioning

confidence: 99%

Synthesis of 1-Thia-5,7-Diazacyclopenta[cd]- Phenalenes from 6(7)-Derivatives of Perimidine

Аксенов

Shcherbakov

Lobach

et al. 2014

Chem Heterocycl Comp

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Electrochemical oxidation of 6(7)-benzoylperimidines was shown to involve two stages of single electron transfer. Based on cyclic voltammetry and microelectrolysis data, a synthetic method was developed for the peri annelation of thiophene ring to benzoyl derivatives of perimidine. A new method was proposed for the preparation of 1-thia-5,7-diazacyclopenta[cd]phenalenes by fusing 6(7)-carbonyl derivatives of perimidine with elemental sulfur.Thiophenes and condensed heterocyclic derivatives of thiophenes are structural elements in many biologically active compounds [1] and potential drugs [2]. Besides that, thiophene derivatives represent useful building blocks for chemical synthesis [3].We have previously developed a method for the peri annelation of thiophene nucleus to 1Н-perimidine derivatives, based on benzoylation of perimidine-6(7)-thiols with benzoic acid in polyphosphoric acid [4]. This method was successfully used for preparing the first two derivatives of the previously unknown 1-thia-5,7-diazacyclopenta[cd]phenalene heterocyclic system.Many of the reactions involving elemental sulfur occur by free radical mechanism [5-8], therefore in the first part of our work we studied the electrochemical oxidation and reduction of 6(7)-benzoylperimidines. Taking into account the high reactivity of radical ion intermediates in the synthesis of sulfur derivatives [9, 10], we considered the possible cyclization of 1H-perimidine carbonyl derivatives with the participation of hydrogen sulfide under the conditions of radical ion initiation at room temperature.The starting substrates for this work were the benzoylperimidines 1а-с. A cyclic voltammetry investigation of these compounds (Table 1, Fig. 1) revealed two stages of electrochemical single-electron oxidation. The first quasi-reversible stage at the potential of Е = 0.72-0.75 V involved the formation of unstable radical cation, which underwent further single-electron oxidation (Е = 1.52-1.62 V), followed by deprotonation. The lack of a proton peak in the cathode segment of the cyclic voltammetry curve indicated the absence of free protons in the solution due to the likely protonation of either the starting compound or alkaline impurities in the solvent.

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Chemistry of Sulfur-Olefin Reactions

Cited by 38 publications

References 9 publications

Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

Shape-Controlled Synthesis of High-Quality Cu₇S₄Nanocrystals for Efficient Light-Induced Water Evaporation

Synthesis of 1-Thia-5,7-Diazacyclopenta[cd]- Phenalenes from 6(7)-Derivatives of Perimidine

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Chemistry of Sulfur-Olefin Reactions

Cited by 38 publications

References 9 publications

Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

Zinc-Based Curing Activators: New Trends for Reducing Zinc Content in Rubber Vulcanization Process

Shape-Controlled Synthesis of High-Quality Cu7S4Nanocrystals for Efficient Light-Induced Water Evaporation

Synthesis of 1-Thia-5,7-Diazacyclopenta[cd]- Phenalenes from 6(7)-Derivatives of Perimidine

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Product

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About

Shape-Controlled Synthesis of High-Quality Cu₇S₄Nanocrystals for Efficient Light-Induced Water Evaporation