نتایج جستجو برای: organic sulfides
تعداد نتایج: 209817 فیلتر نتایج به سال:
A sulfur-assisted five-cascade sequential reaction, wherein the in situ-generated allenyl allyl sulfides undergo thio-Claisen rearrangement, intramolecular Michael addition, and 1, 5-proton migration/aromatization to obtain allyl thiophen-2-yl acetates, propionates, and ketones as the final products, was reported. As a result of the ready availability of starting materials and the extremely sim...
H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are can...
Silicon containing pyridine and quinoline sulfides have been prepared using phase transfer catalytic system thiol/alkyl halide / solid KOH/18-crown-6 / toluene. The target S-ethers were isolated in yields up to 81%. The cytotoxicity of the synthesized compounds was studied. Among pyridine sulfides S-[3-(1-methyl- 1-silacyclohexyl)propyl] derivatives 5e and 6e exhibit the highest cytotoxicity. A...
The difference in the standard Gibbs free energy for the formation of any two oxides or sulfides is the chemical potential for selective reduction of metals from complex minerals. The magnitude of the Gibbs free energy difference is shown by plotting the univariant relationships for relevant sulfides and oxides. In this investigation, three examples of mineral sulfides are considered, and the e...
The soil environment is a primary component of the global biogeochemical sulfur (S) cycle, acting as a source and sink of various S species and mediating oxidation state changes. However, ecological significance of the various S forms and the impacts of human intervention and climate on the amount and structural composition of these compounds are still poorly understood. We investigated the lon...
The structure and distribution of organic sulfur in coals of different rank and different sulfur content were studied by combining mild organic solvent extraction with XPS technology. The XPS results have shown that the distribution of organic sulfur in coal is related to the degree of metamorphism of coal. Namely, thiophenic sulfur content is reduced with decreasing metamorphic degree; sulfoni...
چکیده ندارد.
HPLC, Methylene Sulfides, Methylene Selenides, Selenium Sulfides, Sulfur Heterocycles The Separation of a number of cyclic methylene sulfides and selenides by reversed-phase high-pressure liquid chromatography is reported. The retention times as well as the capacity factors depend in a systematic way on the ring size, the number and kind of chalcogen atoms, and the number of heteronuclear bonds...
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