NH4SCN

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. 

---