Formation of clathrate compounds of the Ni(NCS)2(4-methyl-pyridine)4 complex with methylnaphthalenes and its application to liquid chromatography

✍ Scribed by Janusz Lipkowski; Karol Leśniak; Andrzej Bylina; Danuta Sybilska; Kazimiera Duszczyk

• Book ID: 104146826
• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 447 KB
• Volume: 91
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(01)97908-7

✦ Synopsis

The conditions for the separation of mixtures of monomethylnaphthalenes (MeN) and naphthalene (N) were examined.

The clathrate of formula [Ni(NCS)2(4-methylpyridine)J. 0.7(4-methylpyridine) *0.4(aqueous methanol) formed the stationary phase. The mobile phase was a solution which consisted of 0.43 M 4-methylpyridine and 0.40 M ammonium thiocyanate dissolved in 65 % (v/v) aqueous methanol.

It was established that the monoclinic P2Jc non-clathrate forming a-modification of the complex is chromatographically inactive. Only the presence of the tetragonal clathrate of the p-form, 14,/a, determines the chromatographic activity of the sorbent, and this takes place for low ranges of concentration of the analyzed compounds (GO.1 M). Increasing the concentration of the examined MeNs (20.1 M) leads to the formation of the triclinic y-form, which contains 1.3-2.0 moles of the MeN per mole of the complex. The conditions for utilizing the crystallization of these compounds for the efficient separation (with an enrichment coefficient 25) of 1 -MeN from mixtures with 2-MeN are suggested.