Zinc pyridine thiocyanate

As far as equilibrium constant is concerned, differences between metal ions are perhaps more important than those between ligands. Thus, in the solvent chlorobenzene (41), the equilibrium constant [Eq. (7)] for MC12 and pyridine favors the octahedral configuration for Ni(Il) over that for Co(II) y a factor of 1500 to 2000. In the same solvent, there is no clear evidence that any octahedral zinc compound is formed. The Ni-Co difference cited is actually less than the difference between chloride and thiocyanate against... 

Complexes with pyridine JV-oxide of zinc thiocyanate and selenocyanate of the stoichiometry ZnLsX2 (X = SCN, SeCN) have been reported.1066 IR evidence shows that they are best formulated as [ZnL6]2+[ZnX4f. ... 

Cellulose is insol in w, ale, eth all known simple org solvs. The best solv for it is cuprammonium hydroxide, [Cu(NH3)4(OH)2], also called Schweitzer s Reagent. It is also sol in a coned soln of Ca thiocyanate alone or in combination with formaldehyde. Other solvs gelatinizers for cellulose include zinc chloride (in 40% soln on heating), basic beryllium perchlorate, 84% phosphoric acid, selenic acid, arsenic acid, sulfurous acid, 66% HBr, 70-75% HF, coned HI, chloral with pyridine, chloral hydrate in H2S04, and inorg salts(such as NaCl) in coned solns at high temps. Coned solns of NaOH at ca -10° only partially dissolve cellulose while the remainder is swelled "mercerized . 

Five-hundredths mole of a manganese(II), iron(II),t cobalt(II), nickel(II), copper(II), or zinc(II) salt is dissolved in 300 ml. of distilled water containing 20 ml. of pyridine. To this solution is added slowly with stirring a solution of 8.00 g. of ammonium thiocyanate in 100 ml. of distilled water, and the resulting mixture is allowed to stand in an ice bath until precipitation appears complete (ca. an hour). The precipitate is collected on an 8-cm. Buchner funnel and is washed with three 10-ml. portions of an ethanol-pyridine (9 1) solution. The product is air-dried for not longer than 10 minutes. It is powdered and then dried in a desiccator over potassium hydroxide until constant weight has been attained (ca. 24 hours). In the cases of copper(II) and zinc(II), the dipyridine compound is obtained. Details of separate syntheses are given in Table I. 

In the case of sine, the ammonium thiocyanate solution is first added to the solution of the zinc salt and then the pyridine. The addition of pyridine to a solution of tine salts produces a white gelatinous precipitate. 

Vanadium(V) is reduced to V(II) in 1 M H2SO4 by zinc amalgam. After addition of thiocyanate and pyridine, and adjustment of the pH to 5.2-5.5, the ternary complex is extracted with CHCI3. Hydrogen peroxide is used to strip vanadium [4]. 

The thiocyanate complex of zinc can be extracted by isoamyl alcohol, MIBK, or other oxygen-containing solvents, from acidic solutions [4—6]. Zinc can also be separated as the anionic thiocyanate complex by non-polar solvents (benzene, CHCI3) in the presence of TBP, pyridine, tribenzylamine, Aliquat 336, or Amberlite LA-1 [7-9]. It is possible to separate Zn from Cd. The extraction efficiency increases in the presence of DMF or DMSO [10]. 

V-Ethylpyridinium chloride/DMF (1 /I), A-ethylpyridinium chloride/pyridine (1 /I), trifluoroacetic acid, aqu. solutions of alkalies (ice-cold), beryllium perchlorate, cdcium thiocyanate, cupriammonium hydroxide, cupriethylenediamine, sodium xanthate, tetramethylammonium hydroxide, zinc chloride/hydrochloric acid (cold), zinc chloride (hot), cone, phosphoric acid, cone, sulfuric acid. See also table on cellulose in this Handbook... 

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