Abstract: Meta and para-diisopropylbenzenes cannot be easily separated from each other by distillation because of the closeness of their vapor pressures. m-Diisopropylbenzene can be readily removed from p-diisopropylbenzene by azeotropic distillation using certain ketones. Typical effective azeotropic distillation agents are acetophenone, 2-undecanone and acetonyl acetone.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid--water mixtures by extractive distillation in which extractive agent is a dicarboxylic acid mixed with certain high boiling organic compounds. Examples of effective agents are: itaconic acid and diethylene glycol diethyl ether; azelaic acid, heptanoic acid and 2-hydroxyacetophenone.

Abstract: When 4-methyl-2-pentanone and acetic acid mixtures are subjected to extractive distillation with a dimethyl sulfoxide - pelargonic acid mixture as the agent, the acetic acid is converted to gaseous ketene which is easily recovered from the 4-methyl-2-pentanone.

Abstract: 2-Pentanone cannot be completely removed from 2-pentanone and formic acid mixtures by distillation because of the presence of the maximum azeotrope. 2-Pentanone can be readily removed from 2-pentanone-formic acid mixtures by extractive distillation in which the extractive agent is a ketone, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are cyclohexanone; diisobutyl ketone and octanoic acid; isophorone, hexanoic acid and butyl ether.

Abstract: Meta and para-diisopropylbenzene cannot be easily separated from each other by distillation because of the closeness of their vapor pressures. m-Diisopropylbenzene can be easily removed from p-diisopropylbenzene by azeotropic distillation using certain ethers. Typical effective azeotropic distillation agents are diethylene glycol diethyl ether and dipropylene glycol dimethyl ether.

Abstract: Meta and para-diisopropylbenzenes cannot be easily separated from each other by distillation because of the closeness of their vapor pressures. m-Diisopropylbenzene can be readily removed from p-diisopropylbenzene by azeotropic distillation using certain nitrogenous compounds. Typical effective azeotropic distillation agents are ethanolamine and benzonitrile.

Abstract: 3-Methyl-2-butanone cannot be removed from 3-methyl-2-butanone and formic acid mixtures by distillation because of the presence of the maximum azeotrope between 3-methyl-2-butanone and formic acid. 3-Methyl-2-butanone can be readily removed from 3-methyl-2-butanone - formic acid mixtures by extractive distillation in which the extractive agent is dimethylacetamide, dimethylformamide or these with certain high boiling organic compounds.

Abstract: Meta- and para-diisopropylbenzenes cannot be easily separated from each other by distillation because of the closeness of their vapor pressures. m-Diisopropylbenzene can be readily removed from p-diispropylbenzene by azeotropic distillation using acetophenone. The acetophenone - m-diisopropylbenzene azeotrope can be separated by solvent extraction with propylene glycol to remove the acetophenone and the propylene glycol - acetophenone mixture is readily separated from each other by rectification.

Abstract: Isopropyl acetate cannot be completely removed from isopropyl acetate--isopropanol--water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl acetate can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive agent is a mixture of a polyol and one or higher boiling oxygenated, nitrogenous and/or sulfur containing organic compounds. Typical examples of effective agents are 1,3-butanediol and dimethylsulfoxide; 1,2,6-hexanetriol, dimethylsulfoxide and dimethylformamide.

Abstract: m-Xylene is difficult to separate from o-xylene by conventional distillation or rectification because of the close proximity of their boiling points. m-Xylene can be readily separated from o-xylene by using extractive distillation in which the extractive agent is dimethylsulfoxide or a mixture of it with certain high boiling organic compounds. Typical examples of effective agents are: dimethylsulfoxide; dimethylsulfoxide and 1,4-butanediol; dimethylsulfoxide, nitrobenzene and diethylene glycol.