And NH4SCN

Ring-expansion substitution reactions of 1,3-dithiolanes and 1,3-dithianes with N-halo- and IV-cyano-succinimide give mono-halo- and -cyano-l,4-dithiins and -1,4-dithiepins (Scheme 19). With NBS and BU4NN3 and NBS and NH4SCN, the azido and thiocyanato analogues are formed, respectively.35... 

As a result of interaction of 843 and pyridine, the adduct 845 is formed [53], The structures of coordination compounds 844 and 845 were proved by x-ray diffraction. As shown above (Sec. 3.4.3.2), the direct ammonia synthesis [55,56] with participation of various ligands (especially aliphatic, aromatic, and heterocyclic amines, aminoalcohols), elemental metals (or their oxides), and NH4SCN in mostly non-aqueous media, opens definite possibilities for obtaining thiocyanate complexes. In this respect, transformation (4.9) should be mentioned [57] ... 

Organolithium species may form coloured and EPR-active intermediates not only with conventional acceptors such as carbonyl or imine compounds [14-16] but also with unsaturated inorganic ions such as ambidentate thiocyanate-SCN the reaction between n-BuLi and NH4SCN in the presence of strongly ion-stabilizing hexamethylphosphoric triamide 0 = P(NMe2)3 (HMPA) eventually produced LiNCS 2 HMPA via some unusually colored intermediates and thiocyanate-based radical species [62]. 

The non-hydrated rare earth thiocyanate can be obtained by a reaction between the corresponding metal and NH4SCN in liquid ammonia or by the dehydration of the corresponding hydrated thiocyanate at 1333 Pa and 50 °C. However, the hydrated thiocyanate can be prepared by the following double replacement reactions ... 

Molybdenum and tungsten were quantitatively separated from sea water by the addition of H2O2 and NH4SCN in 0.1 M HCl (for Mo) at a cation-exchange resin ). Elution followed with 0.5 M NaOH/0.5 M NaCl. 

Many salts are soluble in DMSO, so the choice of supporting electrolyte is less restricted than in most other nonaqueous solvents. In general, perchlorates, even KCIO4, nitrates, and halides, are soluble, whereas fluorides, cyanides, sulfates, and carbonates are not thus not only NaC104, LiCl, NaNO, and tetraalkylammonium salts can be used but also such salts as NH4PF6 and NH4SCN. The ability of DMSO to solvate ions is also of importance in the indirect electrolytic hydrodimerization of, for example, acrylonitrile using Na(Hg) [388]. 

In aqueous solution FeCb and NH4SCN form blood-red complexes such as [Fe "(SCN)(H20)5r or the simple Fe(SCN)3. With K4[Fe"(CN)J the deep blue complex Fe4[Fe(CN)6]3 is formed, the Prussian Blue which has been known since 1704. Its deep color is due to electron transfer between Fe" and Fe" Discrete Fe and Fe species can be detected in the crystalline solid Fe4[Fe(CN)ft]3 14-16 H2O. FeCh solutions form black complexes with gallic acid, C6H2(0H)3C00H, which is present in tannin. 

CP MAS NMR spectroscopy has been used to investigate boron nitride. NMR spectra of BN and and BN and NH4SCN have been reported. 

With the permission of your instructor, carry out the following experiment. In a beaker, mix equal volumes of 0.001 M NH4SCN and 0.001 M FeCE (the latter solution must be acidified with concentrated HNO3 at a ratio of 4 drops/L to prevent the precipitation of Fe(OH)3). Divide solution in half, and add solid KNO3 to one portion at a ratio of 4 g per 100 mL. Compare the colors of the two solutions (see Color Plate 3), and explain why they are different. The relevant reaction is... 

Organic acids and phosphate esters [2] NH4SCN FeClj... 

The o-nitrobenzenesulfenamide has been used for the protection of amino acids. o-Nitrobenzenesulfenamides, B, are also cleaved by acidic hydrolysis (HCl/Et20 or EtOH, 0°, 1 h, 95% yield)" by nucleophiles (13 reagents, 5 min-12 h, 90% cleaved) by PhSH or HSCH2CO2H, 22°, 1 h by 2-mercaptopyri-dine/CH2Cl2, 1 min, 100% yield) by NH4SCN, 2-methyl-1-indolylacetic acid and by catalytic desulfurization (Raney Ni/DMF, column, a few hours, satisfactory yield). 

Much success in determining crystal structures has been achieved through high-quality powder X-ray data of polycrystalline powders [57], Structures which have been elucidated include P(EO), LiCF, SO, P(E0)3NaC104, P(EO)4KSCN, P(EO)4 RbSCN, P(EO)4 NH4SCN, and P(EO)3LiN(SO,CF3)2[18,58], All crys-... 

FIGURE 6.9 The endothermic reaction between ammonium thiocyanate, NH4SCN, and barium hydroxide octahydrate, Ba(0H)2-8H20, absorbs a lot of heat and can cause water vapor in the air to freeze on the outside of the beaker. 

Epoxides can be converted directly to episulfides by treatment with NH4SCN and... 

Although this reaction was discussed earlier, it is mentioned here because it is catalyzed by solid acids such as NH4SCN, which provide H+ ions that bond to the pairs of electrons after breaking them loose from the metal. Over a rather wide range of catalyst concentrations, the rate is linearly dependent on the amount of solid acid. Once the NH4+ ion donates a proton, NH3 is lost and the protonated ethyl-enediamine molecule is the acid that remains and continues to catalyze the reaction. While base catalyzed reactions of complexes may be better known, there are many acid catalyzed reactions as well. 

Procedure Pipette 25 ml of a standard 0.1 N AgN03 solution into a glass-stoppered flask (iodine-flask), dilute with 50 ml of DW, add to it 2 ml of nitric acid and 2 ml of ferric ammonium sulphate solution and titrate with ammonium solution to the first appearance of red-brown colour. Each ml of 0.1 N silver nitrate is equivalent to 0.007612 g of NH4SCN. 

Fig. 5.3 Comparison of the temperature-dependent conductivities for amorphous PE0 NH4SCN (circles) and crystalline PEO NH4SCN (squares).

Hall and Hohns have found that 10 /ig of technetiiun can be separated quantitatively from as much as 50 g of molybdenum using the Amberlite IRA-400 anion exchange resin in the perchlorate form. The irradiated metal is dissolved in a NaOH/HjOj mixture and the solution passed through the column. Molybdate is removed by elution with 10% NaOH solution pertechnetate is eluted with 0.5 M NH4SCN. 

Yang et al. (15) spun fibers from a partially (biphasic) nematic solution of cellulose in 1 3/NH4SCN. Tenacities of ca. 3 g/d and moduli of ca. 155 g/d were obtained. 

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