ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The use of a single compound as the agent in modifying the apparent relative volatility in extractive distillation is well known. In the separation of ethylbenzene from para- and meta-xylenes by extractive distillation, it was found that mixtures containing from two to four components were more effective than any known single compound. Hundreds of combinations of extractive agents were investigated in vapor-liquid equilibrium stills, and from these, twenty-seven different combinations of chlorinated organic compounds showed merit. The relative volatility of ethylbenzene to p-xylene is 1.06 and to m-xylene 1.08. The promising combinations were investigated in three glass perforated plate extractive distillation columns containing twelve, fifteen and nineteen theoretical plates, respectively. Of the twenty-seven different extractive agents tested in the columns, sixteen yielded a relative volatility greater than 1.20. The best one, a mixture of pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene, gave a relative volatility of 1.27. Other combinations approaching this relative volatility are pentachlorophenol, benzene hexachloride and 2,4-dichlorotoluene giving 1.25 and polychlorobenzene, pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene giving 1.26, when used in the ratio of two parts of extractive agent to one part of ethylbenzene-xylene mixture. All the extractive agents boil sufficiently above xylene to make their recovery by distillation easy and complete. Life studies showed no excessive decomposition of any of them while in use.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690260523
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