A process for the separation of one or more components in accordance with molecular structure from a mixture of organic compounds

摘要

The separation of desired components in accordance with molecular structure from a mixture of compounds of different molecular structures by contacting with a complex-forming substance, capable of forming complexes with the desired component, followed by separation of the complexes formed, comprises adding to the mixture an auxiliary substance which forms, with the complex-forming substance, complexes having the same crystalline structure as the complexes of the component to be separated and which can be separated by a known method from said component. The complex-forming substance may be urea, for separating straight-chain compounds, e.g. normal hydrocarbons; thiourea for separating branched chain hydrocarbons or naphthenes, e.g. isopentane, iso-octane, cyclohexane or methylcyclohexane; seleno- or telluro-urea; and metallic chlorides, e.g. for separating cholesterol from wool grease, or aromatic hydrocarbons from ethers. If the concentration of the component to be separated is below a critical value, no formation of crystalline complex occurs in the absence of the auxiliary substance. This is preferably similar to the component to be separated, the complexes thereof forming mixed crystals, and the difference in the number of carbon atoms being 4 or less. The separation of the auxiliary substance from the other components may be effected by distillation, and a substance of lower boiling-point is preferred. Extraction or crystallization may, alternatively, be used. Inert auxiliary agents, e.g. diluents, may also be employed. The complex-forming agent may be used alone or as a solution, generally saturated or supersaturated. Complex formation without an auxiliary substance may be used first to separate as much of the desired component as possible. In examples: (1) a fraction containing n-decane is extracted with urea in methanol and, after addition of n-dodecanol, a further extraction is effected; (2) a mixture of hydrocarbons and n-dodecanol is extracted with alcoholic urea and n-decanol added prior to a further extraction; (3) a fraction containing 1,6-dimethyl naphthalene is treated with aqueous antimony trichloride, and further treated after adding a -methyl naphthalene. Specification 686,701 is referred to.