Sulfides combination table

In iron(n) sulfide, FeS, one atom of iron has combined with one atom of sulfur. No such ratio exists in a mixture of iron and sulfur, because the atoms have not chemically combined. Table 2.7 summarises how mixtures and compounds compare. 

Many of the catalysts for the hydrodesulfurization process are produced by combining (Table 5-5) a transition metal (or its salt) with a solid support. The metal constituent is the active catalyst. The most commonly used materials for supports are alumina, silica, silica-alumina, kieselguhr, magnesia (and other metal oxides), as well as the zeolites. The support can be manufactured in a variety of shapes or may even be crushed to particles of the desired size. The metal constituent can then be added by contact of the support with an aqueous solution of the metal salt. The whole is then subjected to further treatment that will dictate the final form of the metal on the support (i.e., the metal oxide, the metal sulfide, or even the metal itself). 

Table 3.3-7 Result of one-pot preparation of optically active sulfoxides 98a-d by a combination of sulfide oxidation and enantiomeric resolution in a water suspension medium.

The equilibrium is more favorable to acetone at higher temperatures. At 325°C 97% conversion is theoretically possible. The kinetics of the reaction has been studied (23). A large number of catalysts have been investigated, including copper, silver, platinum, and palladium metals, as well as sulfides of transition metals of groups 4, 5, and 6 of the periodic table. These catalysts are made with inert supports and are used at 400—600°C (24). Lower temperature reactions (315—482°C) have been successhiUy conducted using 2inc oxide-zirconium oxide combinations (25), and combinations of copper-chromium oxide and of copper and silicon dioxide (26). 

PPS resins must compete with PEI and phenoHcs. There are two domestic manufacturers of poly(phenylene sulfide) Phillips and Fortron Industries. Worldwide there is currently large overcapacity (Table 15). Four Japanese companies, ie, Toso Susteel, a joint venture of Toso/Hodogaya Chemical Toray Toprene, a joint venture of Toto Kasei/Toren Petrochemical and Kureha Chemical have a combined capacity of 82,500 t. U.S. agents sell their materials in the U.S. markets General Electric sells for Toso Susteel Soltex Polymer, part of Solvay, Belgium, sells for Toprene Hoechst-Celanese sells for Kureha. Prices for PPS resins and compounds range from 8.80/kg for unreinforced resin to 3.30/kg for 65% filled resins. 

Based on these considerations, Croft prepared six formulations containing various combinations of NBR and NBR/PVC with CR and SBR and measured their oil, heat and ozone resistance, physical properties, and adhesion characteristics. Whereas the physicals are satisfactory for aU compounds, formulations based on NBR, NBR/PVC with CR performed better on heat and oil aging than the compounds containing SBR as shown in Tables 11.6 and 11.7. However, the adhesion is better with the latter compounds. It has been suggested that cuprous sulfide formed on the wire surface interacts with the double bond in SBR to provide the improvement in adhesion. 

Table 11 Result of one-pot preparation method of optically active sulfoxides (64a-d) by a combination of oxidation of sulfide and enantiomeric ...

Knowledge of the 90 chemical elements and their properties in compounds led to the construction, by man, of a unique table of elements, the Periodic Table, of 18 Groups in six periods in a pattern fully explained by quantum theory, described in Chapter 2. There is then a huge variety of chemical combinations possible on the Earth and limitations on what is observable are related to element position in this Table. It also relates to the thermodynamic and/or kinetic stability of particular combinations of them in given physical circumstances (Table 11.3). The initial state of the surface of the Earth with which we are concerned was a dynamic water layer, the sea, covering a crust mainly of oxides and some sulfides and with an atmosphere of NH3, HCN, N2, C02(C0, CH4), H20, with some H2 but no 02. This combination of phases and their contents then produced an aqueous solution layer of particular components in which there were many concentration restrictions between it and the components of the other two layers due to thermodynamic stability, equilibria, or kinetic stability of the chemicals trapped in the phases. It is the case that equilibrium... 

Appendix 2 was compiled and formatted by eomposition paralleling the presentation for the fibrous minerals. The list, in eontrast with that of the minerals, shows a predominanee of simple chemical compounds that combine two or three elements. One-third of the reeorded synthetie fibers are of elements or binary alloys. Another third are compounds such as sulfides, phosphides, and halides that do not eontain oxygen (Table 2.9). Only three synthetic fibrous silicate compounds etre listed, although undoubtedly other experimental silicate combinations have been made but not recorded by us. 

A one-pot procedure combines the generation of trimethylsulfonium hydrogensulfate (Me3S HS04 ) from dimethyl sulfide, sulfuric acid and methanol, and its use in situ for oxirane formation with carbonyl compounds [451] (Table 4.5). 

The Gibbs phase rule is the basis for organizing the models. In general, the number of independent variables (degrees of freedom) is equal to the number of variables minus the number of independent relationships. For each unique phase equilibria, we may write one independent relationship. In addition to this (with no other special stipulations), we may write one additional independent relationship to maintain electroneutrality. Table I summarizes the chemical constituents considered as variables in this study and by means of chemical reactions depicts independent relationships. (Throughout the paper, activity coefficients are calculated by the Debye-Hiickel relationship). Since there are no data available on pressure dependence, pressure is considered a constant at 1 atm. Sulfate and chloride are not considered variables because little specific data concerning their equilibria are available. Sulfate may be involved in a redox reaction with iron sulfides (e.g., hydrotroilite), and/or it may be in equilibrium with barite (BaS04) or some solid solution combinations. Chloride may reach no simple chemical equilibrium with respect to a phase. Therefore, these two ions are considered only to the... 

Table III shows the abundance of various elements in the earth s crust and the oxidation states they frequently occupy. The table indicates that of the 14 most abundant elements, only six participate in redox reactions in the surface layers of the earth. [PH3 seems to be extremely rare (42) and will not be discussed.] Because by definition free oxygen as 02 is absent in the anoxic zone, it is evident that oxides of Fe(III) are the most important oxidizers in anoxic environment and that S042 and higher oxides of manganese are of importance only locally. Reducing compounds of importance are organic matter and sulfides, the latter frequently from volcanic emanations. Hydrogen is commonly combined with other elements, as in H20, CH4, and NH3 but may locally occur free as H2. Since iron is the most widespread element that can serve as an oxidizer in the anoxic environment the distribution of the valence states of iron in various rocks is of interest (see Table IV). Sandstones frequently have a high Fe203/Fe0 ratio, but shales and clays may also be highly oxidized as shown in Tables IV and V. Since approximately 75% of the earth s surface is covered with sediments and since the sediments...

The major breakthrough in this field was achieved in 2003 by Legros and Bolm [164], who reported a highly enantioselective iron-catalyzed asymmetric sulfide oxidation. Optically active sulfoxides were obtained with up to 96% ee in good yields under very simple reaction conditions using Fe(acac)3 as precatalyst in combination with a Schiff base-type ligand (Table 3.9). Furthermore, inexpensive and safe 35% aqueous hydrogen peroxide served as terminal oxidant. 

Bach and Korber reported in 1998that iron(I I) chloride could be used in combination with tert-butyloxycarbonyl azide (BocN3) for nitrene transfer to sulfides and sulfoxides [170], Whereas usually 1 equiv. of FeCl2 was employed in the imination of sulfoxides, catalytic amounts of this iron salt (25mol%) could also be applied (Table 3.13). 

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