| 摘要 |
<p>1,144,067. Separating xylene isomers. JAPAN GAS-CHEMICAL CO. Inc. 2 June, 1966 [3 June, 1965 (2)], No. 24693/66. Heading C5E. m-Xylene is continuously extracted from a mixture of xylene isomers (including ethylbenzene) by charging the xylene mixture together with a diluent (e.g. hexane or CCl 4 ), liquid HF, and BF 3 (and optionally reflux mxylene) to an extractor operating under selected operating conditions which are defined in detail in terms of ratios between various components of the total charge, the m-xylene passing as a complex into the HF phase, from which it may be recovered by stripping and fractionation. Part of the crude or pure mxylene may be used as the reflux to the extractor. The remaining mixture of xylene isomers may be further treated to separate by fractionation an ethylbenzene fraction, and a mixed fraction of o- and p-xylenes, which can then be further fractionated to separate the two isomers. The p-xylene may be further purified by crystallization. Part or all of the m and/or o-xylene products may be isomerized to form an equilibrium mixture of xylene isomers which is returned for further extraction.</p> |
