Rhodanide ions

The thiocyanate ion, S=C=N , also called the rhodanid ion in the early German literature because of the intense red color of its Fe derivative, is obtained by the fusion of alkah metal cyanides with sulfur. It is also the product of the detoxification of the cyanide ion in living systems. Most thiocyanate salts are very soluble in both water and liquid ammonia and are usefiil soluble sources of metal ions in liquid ammonia. Thiocyanogen, N C S , is... 

The monolayers of cationic polysoaps were studied at the air-water interface [73,74]. A direct relation between the anion adsorption and the monolayer selectivity towards a given counterion was established. In particular, such a monolayer exhibits an ideal selectivity towards rhodanide ions in the concentration regions where they were adsorbed at the interface. When other counterions in the monolayer replace rhodanide ions, the dependence of the monolayer potential on the ion concentration no longer obeys the Nernst equation. 

Perchlorates (see Section 6.3.2.2) and some degradation products of glucosinolates, such as goitrin, isothiocyanates, nitriles and thiocyanate (rhodanide) ions (SCN ), have goitrogenic (antithyroid) activities. Thiocyanate ions also arise in the body as detoxification products of cyanides. The other compounds that show antithyroid activity are some congeners of polychlorinated biphenyls (PCBs), some pesticides and a number of veterinary drugs containing thiourea residues (such as thiouracils, aminothiazoles and mercaptoimidazoles) that inhibit the enzyme thyroid peroxidase. These substances may be present in foods as contaminants (see Section 12.8.3.1). 

Here the counter-ions were Cl-, acetate, iodate, nitrate, bromide, iodide and rhodanide. 

Figure 1.130 Optical inspection of mixing in the SAR mixer. The applied total volume flow rate of 0.2 I IT1 is the same as for the experiment shown in Figure 1.129. Starting from a bi-lamination of yellowish iron ion (Fe3+) and transparent rhodanide (SChT) solutions, homogeneous mixing is achieved in the eighth mixing step, indicated by the deep brown color of the iron-rhodanide complex formed [7] (by courtesy of RSC).

Radical cations act both as electrophiles and one-electron oxidants toward nucleophiles (Eberson, 1975 Bard et al, 1976 Eberson et al., 1978a,b Evans and Blount, 1978) as shown in (6), and it is therefore important to find out which factors govern the competitition between these reaction modes. Evans and Blount (1978) measured rate constants and products for a number of [9,10-diphenylanthracene)+ /nucleophile reactions and found that iodide, rhodanide, bromide and cyanide undergo oxidation, whereas nucleophiles that are more difficult to oxidize form a C—Nu bond directly. Entry no. 13 of Table 15 shows non-bonded electron transfer to be feasible for these ions, and the reactions of [perylene]+ with iodide, rhodanide and bromide (entry no. 14) presumably can be classified in the same way. The reaction with chloride ion... 

This library was exposed to a solution of Ni(II) acetate or Fe(III) chloride in order to find the most efficient ligands for these ions among the synthesized compounds. The detection of the most stable complexes could easily be accomplished using classic color reactions (dimethylglyoxime for nickel and potassium rhodanide for iron). The colored resin beads were then selected under the microscope. Actually, certain structures proved to have a very high affinity for each of these ions. In the case of sufficiently dilute Ni(II)-solutions the metal... 

Finally, it should be said that the above-discussed osmotic pressure-forced retention of one of the components of a mixture subjected to separation according to size exclusion mechanism does not exclude the possibility of true retention-type solute/sorbent interactions. Hypercrosslinked polystyrene may well enter attractive interactions with soft and lipophilic (chaotropic [163]) anions, such as sulfide, thiosulfate, rhodanide, perchlorate, tetrafluoroborate, and hexafluorophosphate. Also, some cations such as silver, copper, and mercury may interact with the aromatic 71-systems of the polystyrene matrix, which will retard the movement of the ions. These interactions may contribute to the separation of the ions from their stiU larger competing ions, but they may also be counterproductive to the size exclusion effect and deteriorate the separation of the retarded ions from smaller species. 

The tests demonstrate that upon varying content of phenols in the used water the ozonation is one of the most promising methods for their removal. The ozonation was foimd to be applicable for the decomposition of rhodanide in neutral and weak acid medium in the temperature range of 9-25°C. The ozone consiunption in this case is 2 mg/mg. The ozone uptake for the oxidation of the cyanide ion (CN ) is 1.8 mg/mg. 

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