Abstract: Isopropyl ether cannot be completely removed from isopropyl ether-isopropanol-water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl ether can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are ethylene glycol; dimethylsulfoxide plus propylene glycol; dimethylsulfoxide plus dimethylformamide plus diethylene glycol diethyl ether.

Abstract: n-Butyl acetate cannot be completely removed from n-butyl acetate-n-butanol--water mixtures by distillation because of the presence of the minimum ternary azeotrope. n-Butyl acetate can be readily removed from mixtures containing it, n-butanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are N,N-dimethylacetamide, dimethylsulfoxide and acetamide, ethylene glycol propylene glycol, dimethylsulfoxide and acetamide.

Abstract: Methanol cannot be completely removed from its mixture with acetone by distillation because of the presence of the minimum binary azeotrope. Methanol can be readily removed from mixtures containing it and acetone by using extractive distillation to bring off the methanol as overhead product in a rectification column by using extractive distillation in which the extractive distillation agent is an effective higher boiling organic compound or a mixture of these. Typical examples of effective agents are acetophenone, 3-pentanone, 2,4-pentanedione, ethylacetoacetate, 2-butanone plus benzil.

Abstract: m-Xylene is difficult to separate from o-xylene by conventional rectification or distillation 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 ethyl-2-hydroxybenzoate; propoxypropanol puls 1,4-butanediol; sulfolane plus dimethylsulfoxide plus ethyl benzoate.

Abstract: Quaternary azeotropic mixtures of 1,1,2-trichloro-1,2,2-trifluoroethane, methylene chloride, methanol and cyclopentane are provided. These azeotropic mixtures are useful as solvents to remove buffing compounds residues. These mixtures are useful not only because of their high solvency characteristics but also because they exhibit essentially the constant boiling characteristics of an azeotrope which is formed between these components, thereby facilitating handling and purification of the solvent mixtures without significantly altering their compositions. [The quaternary mixtures disclosed herein exhibit certain advantageous solvency characteristics of glycol based compositions, over the known binary or ternary azeotropic systems containing 1,1,2-trichloro-1,2,2-trifluoroethane, methylene chloride, methanol and cyclopentane.

Abstract: A method for separating ethyl acetate from methyl ethyl ketone is described including distilling in an anhydrous condition a mixture of ethyl acetate-methyl ethyl ketone in a plate column in the presence of an effective amount of an organic extractive solvent which has the following properties: (1) is soluble in a boiling ethyl acetate-methyl ethyl ketone mixture; (2) does not form an azeotrope with ethyl acetate or methyl ethyl ketone; (3) boils higher than ethyl acetate and methyl ethyl ketone and (4) in combination with the ethyl acetate-methyl ethyl ketone mixture, results in a relative volatility of ethyl acetate to methyl ethyl ketone greater than 1.20.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether-acetone mixtures by distillation because of the presence of the minimum binary azeotrope. Isopropyl ether can be readily removed from mixtures containing it and acetone by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are: dimethylsulfoxide; sulfolane and propylene glycol; glycerine, ethylene glycol and adiponitrile.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether - methyl ethyl ketone mixtures by distillation because of the presence of the minimum binary azeotrope. Isopropyl ether can be readily removed from mixtures containing it and methyl ethyl ketone by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are sulfolane; ethylene carbonate plus dimethylsulfoxide; adiponitrile plus dimethylformamide plus glycerine.

Abstract: A process for the separation of a dissolved solid from an aqueous solution containing it, comprising the steps of (a) adding thereto an organic liquid which is a poor solvent for the dissolved solid and which forms an azeotrope with water, (b) subjecting the mixture to azeotropic distillation to separate at least a major portion of the water, (c) cooling the mixture thereby causing substantially complete separation of the dissolved solids, and (d) separating same from the mother liquor.

Abstract: A novel composition, and extraction process for the dehydration of a hydrated aliphatic, monohydric alcohol to produce a fuel grade alcohol. A select group of alkali-metal and alkaline-earth metal salts are added to and dissolved within a low volatility polyhydric alcohol to form a solution, or solvent extractant, and said solvent extractant contacted and dissolved within said aliphatic, monohydric hydrated alcohol, the solvent extractant distilled, condensed, and a dehydrated fuel grade aliphatic monohydric fuel grade alcohol recovered.

Abstract: Ethyl acetate cannot be completely removed from ethanol and water mixtures by distillation because of the presence of the minimum ternary azeotrope. Ethyl acetate can be readily removed from mixtures containing it, ethanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated of nitrogenous organic compound or a mixture of these. Typical examples of effective agents are: dimethylsulfoxide, glycerine and diethylene glycol, 1-naphthol, hydroquinone and N,N-dimethylformamide.

Abstract: A level-controlled water tank in an extractive distillation system is used to maintain the water concentration in the solvent mixture constant.

Abstract: A method of purification of crude .beta.-phenylethyl alcohol to give a highly pure .beta.-phenylethyl alcohol suitable as a perfume, which comprises subjecting the crude .beta.-phenylethyl alcohol to azeotropic distillation in the presence of an azeotropic solvent selected from water, an alkylene glycol, an alkylene glycol monoalkyl ether and a mixture of two or more kinds of these solvents, or extractive distillation in the presence of an extractive solvent selected from glycerine, an alkylene glycol, a polyalkylene glycol, an alkylene glycol monoalkyl ether, a polyalkylene glycol monoalkyl ether and a mixture of two or more kinds of these solvents.

Abstract: A process for distilling vinyltoluene comprising subjecting vinyltoluene to distillation conditions in the presence of a synergistic polymerization inhibiting mixture of N-nitrosodiphenylamine (NDPA) and dinitro-para-cresol (DNPC). Preferably from about 100 to about 300 ppm by weight NDPA and about 300 to about 700 ppm by weight DNPC are dissolved in the crude vinyltoluene and the resulting solution is vacuum distilled.

Abstract: Ethylbenzene and para-xylene and/or meta-xylene are difficult to separate by distillation because they boil only 2.3 C..degree. and 3.1 C..degree. apart. Ethylbenzene can be readily separated from the xylenes by using extractive distillation in which the extractive distillation agent is a mixture of pentachlorophenol admixed with certain chlorinated and/or oxygenated organic compounds boiling higher than the xylenes. A typical mixture comprises pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene.

Abstract: A process for isolating a conjugated diolefin from a C.sub.4 - or C.sub.5 -hydrocarbon mixture containing the diolefin, by single-stage or multi-stage extractive distillation using a selective solvent, wherein the selective solvent is a solvent mixture which comprises(a) from 1 to 99 percent by weight of an N-alkyl-substituted lower aliphatic acid amide or of an N-alkyl-substituted alicyclic acid amide having 5 ring members and(b) from 1 to 99 percent by weight of an aliphatic or alicyclic ether boiling at from 30.degree. C. to 200.degree. C.

Abstract: A process for recovering alkoxyketone compounds from mixtures of the alkoxyketone compound and the corresponding 1-alkoxy-2-alkanol compound by extractive distillation with diols, triols and polyols as extractants, wherein said mixtures contain an organic or inorganic base.

Abstract: A process for extracting essentially pure unsymmetrical dimethyl hydrazine UDMH) from a solution containing UDMH, water, and other volatiles and non-volatiles, comprises charging a distillation stillpot with the UDMH solution, mixing into the solution sufficient caustic sodium hydroxide so as to cause the solution to separate into a two layer system, mixing isopropanol into the two layer system, and distilling off the essentially pure UDMH distillate.

Abstract: In the extractive distillation of C.sub.5 hydrocarbons with different degrees of unsaturated using acetonitrile, an increase in the selectivity of acetonitrile is obtained when also using with acetonitrile small amounts of at least one compound selected from the group consisting of dimethylformamide, dimethylsulfoxide, morpholine, furfural, N-methylpyrrolidone, 3-methoxypropionitrile, gamma-butyrolactone, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol monoethyl ether.

Abstract: A mixture of methylethylsulfone and at least one compound from the group including methylethylketone, acetone, and tetrahydrofuran is employed as a selective solvent in extractive distillation process for separation of diolefins from olefins.

Abstract: In a process of extractive distillation, the combination of operating with two liquid phases in at least the uppermost trays of the column, preferably while maintaining the column operation at substantially an optimum reflux ratio, results in increased efficiencies and minimum requirements for selective solvent.

Abstract: Process for removing hydrochloric acid and other impurities which are contained in vinyl chloride monomer, by treatment in a distillation zone, comprising the addition to crude vinyl chloride, in the course of distillation thereof, of at least one alcohol selected from the group of C.sub.4 to C.sub.10 tertiary aliphatic alcohols and C.sub.3 to C.sub.10 primary or secondary alcohols with unsaturation in the alpha position, and rectifying the vinyl chloride monomer from the resulting mixture.