653. ------. [FETTERLY, L. C.] (N. V. de Bataafsche Petroleum Maatschappij). [Fractional Extraction and Crystallization of Hydrocarbon Mixtures in the Form of Complex Compounds With Urea and Thiourea.] French Patent 964,694, Aug. 22, 1950; appl. file

Patent Abstracts

653. ------. [FETTERLY, L. C.] (N. V. de Bataafsche Petroleum Maatschappij). [Fractional Extraction and Crystallization of Hydrocarbon Mixtures in the Form of Complex Compounds With Urea and Thiourea.] French Patent 964,694, Aug. 22, 1950; appl. filed Apr. 15, 1948. Chem. Zentralb., 1951, I, p. 2383.

Isomeric hydrocarbon mixtures, such as octane and isooctane and hydrocarbons, which were obtained by alkylation, isomerization, and aromatizaion, may be separated. To facilitate the fractional separation, a part of the complex mixture from a preceding operation is added to the initial mixture. Normal paraffins and olefins, strongly unsaturated compounds, normal alcohols with at least 6C atoms, as well as etherlike compounds such as acetals, dioxan, paraldehyde and esterlike compounds such as amylacetate, amines, acid amides, and mercaptans form crystalline complexes with urea. To the hydrocarbons that form complexes with thiourea belong branched and naphthenic hydrocarbons such as isobutane, isopentane, 2.2-dimethylpropane, isohexane, and 2-methylpentane.