Patent GB-811137-A (GB)
Title: Process for resolving mixtures of organic compounds
Inventor: SCHAEFFER WILLIAM DONALD
IPC: C07B63/02
Filed: 1956-12-03
Abstract: A process of separating a mixture of organic compounds comprising an aromatic compound into its components comprises contacting said mixture with a solid Werner complex, whereby said aromatic compound is preferentially absorbed by the Werner complex to form a clathrate compound and recovering the aromatic compound from the clathrate compound, the Werner complex consisting of one mol. of a salt of a metal of atomic number above 12 coordinated with at least two mols. of a N-heterocyclic nitrogen base.  The feed mixture may be dispersed in an immiscible liquid such as water or dissolved in a solvent before contact with the Werner complex, or the latter may be dissolved in a solvent which does not form a clathrate therewith, the feed mixture added to the solution, and the clathrate precipitated. Also, the feed mixture may be mixed with the N-heterocyclic nitrogen base, either as a solution or an emulsion, and the whole added to an aqueous solution of the metal salt.  The aromatic compound may be stripped from the clathrate with (1) a solvent for the compound which is not a solvent for the complex at a temperature higher than the clathration temperature; or (2) an aqueous agent with agitation, the agent dissolving neither the complex nor the aromatic compound; (3) steam containing an equilibrium proportion of the N-heterocyclic nitrogen base, and condensing the effluent steam.  In examples: (1) a mixture of the three xylenes and ethylbenzene is mixed with g -picoline or with 4-methyl-1.2.5-triazine and added to a nickel thiocyanate solution, or the same feed mixture, alone or diluted with kerosene, added to the solid nickel thiocyanate g -picoline complex, and the clathrate stripped with aqueous hydrochloric or steam to give a product enriched in p-xylene; (2) a mixture of the cymenes is enriched in the p-isomer by clathration with nickel tetra-(g -picolino) dithiocyanate which is dissolved in a mixture of g -picoline and methyl cellosolve or which is in powdered form together with a mixture of water and a dispersing agent or water and methanol; (3) further examples describe the separation of xylenes, p-chlortoluenes, dichlorobenzenes, toluidines, nitrotoluenes, cresols, methyl anisoles, naphthalene and diphenyl, 1- and 2-methyl naphthalenes, and o- and p-phthalic acids using complexes containing manganese, iron, nickel or cobalt as cation, formate, cyanide, chloride, nitrite, cyanate, or thiocyanate radicals as anions, and the following heterocyclic bases: 3-cyanopyridine, 3-aminopyridine, methyl or ethyl isonicotinate, 4-ethyl pyridine, 4-hydroxymethylpyridine, 4-methylpyridine, 3-ethyl-4-methyl-pyridine, 4-acetyl-pyridine, 4-cyanopyridine, isonicotinamide, 3-bromopyridine, 4-aminopyridine, isothionicotinamide, 4-benzylpyridine, 2.3-dibromopyridine, isoquinoline, 4-vinylpyridine.  Other hydrocarbon mixtures which may be separated are specified and other non-hydrocarbon mixtures specified are: the methyl o-, m- and p-toluates nitronaphthalenes, aminonaphthalenes, aniline and nitrobenzene, coumarin and vanillin, furan and thiophene, sodium cresylates, potassium terephthalate and isophthalate, dimethyl iso-, tere- and orthophthalates, sodium toluene sulphonates, sodium methyl naphthalene sulphonates, estriol and estrone or estradiol, picolinic and nicotinic acids, thymol and menthol, sodium naphthol sulphonates, aminobenzaldehydes, benzine and p-semidine, dinitrochlorbenzenes, isosafrol and piperonal, the vanillins, phenylene diamines, phenetidine and phenacetin, methyl thiophenols, diazoaminobenzene and aminoazobenzene, aniline and dimethylaniline, benzoic esters, tere- and iso-phthalonitrile, tolunitriles, methyl salicylate and methyl p-hydroxybenzoate, methyl acetanilides, aminobenzenesulphonamides, sodium anthranilate and phthalamate, picolines and lutidines.