Ammonium amyl ions

Silver, lead, copper(l). and thallium(I) thiocyanates are insoluble and mercuiy(II), bismuth, and tm(II) thiocyanates slightly soluble. All of these, are soluble in excess of soluble (e.g., ammonium) thiocyanate, forming complexes. Iron(III) thiocyanate gives a blood-red solution, used in detecting either Fe(lll) or thiocyanate in solution, and is extracted from water by amyl alcohol. It is not formed in the presence of fluoride, phosphate and other strongly complexing ions,... 

High molecular-weight amines are of particular importance in the extraction [35-39]. They form ion-associates with acids (e.g., HSCN, HReOa, HI), metal-complex acids [e.g., H2PtCl6, HFeCU, H2U02(S04)2]2, and heteropoly acids. These complexes are extractable into non-polar solvents (e.g., CeHa, CHCI3, CCI4) and polar solvents (e.g., MIBK, amyl alcohol). Tertiary amines, such as tribenzylamine (TBA) and tri-n-octylamine (TOA) are most commonly used. Tertiary and secondary amines are used for extraction of anions from acid solutions, whereas quaternary ammonium salts enable also extraction from neutral and alkaline solutions. Secondary and tertiary amines and quaternary ammonium salts are applied as solutions in non-polar solvents. Diphenylguanidine (formula 1.13) is also frequently used in extraction. 

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