Reaction with sulfide ion

The mesoionic 1,3,2-oxathiazolone (12) behaves in its reaction with sulfide ion (Scheme 17) (76MI43400) more as structure (12b) than the generally accepted azolylium-5-olate form (12d), consistent with X-ray bond parameters (see Section 4.34.2.3.1). 

The reaction with sodium sulfite or bisulfite (5,11) to yield sodium-P-sulfopropionamide [19298-89-6] (C3H7N04S-Na) is very useful since it can be used as a scavenger for acrylamide monomer. The reaction proceeds very rapidly even at room temperature, and the product has low toxicity. Reactions with phosphines and phosphine oxides have been studied (12), and the products are potentially useful because of thek fire retardant properties. Reactions with sulfide and dithiocarbamates proceed readily but have no appHcations (5). However, the reaction with mercaptide ions has been used for analytical purposes (13)). Water reacts with the amide group (5) to form hydrolysis products, and other hydroxy compounds, such as alcohols and phenols, react readily to form ether compounds. Primary aUphatic alcohols are the most reactive and the reactions are compHcated by partial hydrolysis of the amide groups by any water present. 

Depending on the conditions, the reaction of diacetylene with sulfide ions leads either to di(2-ethynylvinyl)sulfide (46) (79ZOR1554) or thiophene (76DIS 80GEP2818580 81KGS1694), the product of cyclization of ethynylvinylthio anion or of the corresponding thiol. 

In type A reaction soluble sulfide ions combine with metal ions to form a precipitate of insoluble metal sulfide. Sulfur s oxidation state of minus two does not change in this reaction. The reaction is... 

Reaction of dihalides with sulfide ion (cyclic sulfides)... 

It is well established that sulfur compounds even in low parts per million concentrations in fuel gas are detrimental to MCFCs. The principal sulfur compound that has an adverse effect on cell performance is H2S. A nickel anode at anodic potentials reacts with H2S to form nickel sulfide. Chemisorption on Ni surfaces occurs, which can block active electrochemical sites. The tolerance of MCFCs to sulfur compounds is strongly dependent on temperature, pressure, gas composition, cell components, and system operation (i.e., recycle, venting, and gas cleanup). Nickel anode at anodic potentials reacts with H2S to form nickel sulfide. Moreover, oxidation of H2S in a combustion reaction, when recycling system is used, causes subsequent reaction with carbonate ions in the electrolyte [1]. Some researchers have tried to overcome this problem with additional device such as sulfur removal reactor. If the anode itself has a high tolerance to sulfur, the additional device is not required, hence, cutting the capital cost for MCFC plant. To enhance the anode performance on sulfur tolerance, ceria coating on anode is proposed. The main reason is that ceria can react with H2S [2,3] to protect Ni anode. 

In the reaction presented above, oxygen shares electrons with sulfide ion which is unlike that from oxidation-reduction processes described later where transfer of electrons occurs. 

Hariita et al. (14) prepared spherical particles of molybdenum sulfide and cobalt sulfide with a narrow size distribution by reaction of dilute ammonium orthomolybdate or cobalt(II) acetate with sulfide ions liberated from thioacetamide as a reservoir of S2- ions in weakly acidic media. The compositions of these metal sulfides were estimated to be Mo S 0 = 1.0 1.7 3.0 and Co S 0 = 1,0 4.5 6.4 by chemical analysis. Figure 3.1.4 shows an SEM of a thus prepared uniform molybdenum sulfide particles sample. These sulfide particles were of no distinct crystal structure as shown by x-ray diffractometry. The isoelectric points of the Mo sulfide and Co sulfide particles in terms of pH were 1.9 and 3.1, respectively. Both of them are useful as hydrodesulfurization catalysts. 

Reaction of 86 with sulfide ion produces both meso (235) and racemic (236) diastereomers of bis(6-trans-l-hydroxycyclohexa-2,4-dienyl) sulfide. 

The convenient route to [Fe4S4(SR)4]2, using FeCl3, RS and sulfur, depends on thiolate reducing half of the iron(III) to iron(II), and all of the sulfur to sulfide. As a result more thiolate is required than with procedures starting with sulfide ion. This requirement can be reduced by using an iron(II) salt765 rather than iron(III). The overall reaction is then as in equation (70). 

Deactivation of growing carbenium ions by reaction with sulfides is evidently very fast. Sulfonium ion formation is exothermic (AH = -40 kJ/mol) and exoentropic (AS = -74 J/mol-K) [271]. High equilibrium constants (Keq = 104 moI-1L) for sulfonium ion formation were calculated from the apparent rate constants of propagation and the rate constants of carbocationic growth. Dynamic NMR experiments of model systems with tetrahydrothiophene indicate that the bimolecular deactivation rate constant is kdeacl 106 mol-1-Lsec-1 at 0° C (AH = 20 kJ/mol, AS = -37 J-mol-K), and that activation is faster than bimolecular exchange (k act foe) [67]. 

Very early in the study of sulfide mineral biodegradation, it was discerned that microbially-regenerated ferric ions constituted a very potent reagent for indirect attack (for literature, see Kuznetsov et al., 1963 Silverman and Ehrlich, 1964 Zajic, 1969). The ubiquitous occurrence of iron in natural situations and the wide range of reactions with sulfide minerals that can occur, combine to make the ferric ion, either as such or in complex form, the most important chemical species involved in indirect attack mechanisms. The general reaction, known to be applicable to a number of sulfide minerals under aerobic conditions (Bryner et al., 1954 Ivanov et al., 1961), may be expressed as ... 

Further reaction of the sulfenyl chlorides to the sulfides does not take place. It can also be deduced that the substitution reaction occurred with the chelate ring unruptured, since no sulfides (usually obtained with sulfur dichloride and the enol form of 2,4-pentanedione) were obtained. The structures of the sulfenyl chlorides of the metal acetylacetonates were confirmed by their infrared spectra, and by conversion of the sulfenyl chloride to a thiocyano group by reaction with cyanide ions. The tris(3-thiocyano-... 

Under anaerobic conditions. Mo reacts readily with sulfide ion to form a number of stable thiomolybdate complexes (MoO S4l ) which have been detected by the oxine chelate method (Magyar et al, 1993). A number of insoluble sulfides can be precipitated including M0S2 and M0S3. Very often, the Mo sulfides are co-precipitated with FeS according to the reaction first proposed by Bertine (1972) ... 

Another step in the qualitative analysis of cations (see Exercise 28) involves precipitating some of the metal ions as the insoluble sulfides (followed by subsequent treatment of the mixed sulfide precipitate to separate the individual ions). Write balanced net ionic equations for the reactions of Co(ll), Co(lll), Fe(ll), and Fe(lll) ions with sulfide ion,... 

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