Abstract: Heptane cannot be removed from heptane-vinyl acetate mixtures by distillation because of the minimum boiling azeotrope. Heptane can be readily removed from vinyl acetate by extractive distillation. Typical effective agents are dimethylsulfoxide, phenol, diisobutyl ketone and hexyl acetate.

Abstract: Octene-1 is difficult to separate from several of its isomers by conventional distillation or rectification because of the closeness of their boiling points. Octene-1 can be readily separated from its close boiling isomers by azeotropic or extractive distillation. Effective agents are: for azeotropic distillation, t-amyl methyl ether; for extractive distillation, isophorone.

Abstract: The separation of vinyl acetate from methyl acrylate by distillation is difficult because of the closeness of their boiling points. Vinyl acetate can be readily removed from methyl acrylate by extractive distillation. Typical effective agents are phenol, methoxyethanol and isobutyl vinyl ether.

Abstract: A process for separating phenol obtained by the decomposition of cumene hydroperoxide from high boiling impurities, includes the following steps:a) feeding phenol rectification bottoms comprising phenol, acetophenone, cumylphenol, alpha-methylstyrene dimers and high boiler residues to a first phenol freeing distillation column A;b) feeding concentrated bottoms with substantially reduced phenol content from column A to a second residue concentration distillation column B;c) withdrawing a stream rich in compounds boiling between phenol and residue, particularly cumylphenol, from said column B from a point below the feed and returning at least a portion of said stream to said column A at a point above the feed;d) recovering overheads from column A comprising at least 95 weight percent phenol; ande) recovering acetophenone-rich overheads from column B comprising at least 70 weight percent acetophenone.

Abstract: Hexane cannot be removed from hexane--vinyl acetate--methyl acrylate mixtures because of the ternary azeotrope. Hexane can be readily removed from hexane--vinyl acetate--methyl acrylate mixtures by extractive distillation. Typical effective agents are phenol, diethylene glycol methyl ether and 2-nitropropane.

Abstract: Hexane cannot be removed from hexane - vinyl acetate mixtures by distillation because of the minimum boiling azeotrope. Hexane can be readily removed from vinyl acetate by extractive distillation. Typical effective agents are phenol, 1-nitropropane and benzyl alcohol.

Abstract: Formic acid cannot be completely removed from formic acid--water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is cyclohexanone, isophorone or a mixture of these with certain organic compounds. Typical examples of effective agents are cyclohexanone; isophorone; cyclohexanone and neodecanoic acid; isophorone and diisobutyl ketone.

Abstract: Tetracholorethylene cannot be completely separated from n-butanol, isobutanol or 2-butanol by conventional distillation or rectification because of minimum boiling azeotropes. Tetrachloroethylene can be readily separated from n-butanol, isobutanol or 2-butanol by extractive distillatiion. Typical effective agents are: for n-butanol, dipropylene glycol methyl ether; for isobutanol, dimethylsulfoxide and isobutyl butyrate; for 2-butanol, ethylene glycol methyl ether and isobornyl acetate.

Abstract: Trichloroethylene cannot be completely separated from n-butanol, isobutanol, 2-butanol or t-butanol by conventional distillation or rectification because of the minimum boiling azeotropes. Trichloroethylene can be readily separated from n-butanol, isobutanol, 2-butanol or t-butanol by extractive distillation. Typical effective agents are: for n-butanol, dimethylsulfoxide; for isobutanol, n-octanol; for 2-butanol, 2-methyl-1-pentanol and for t-butanol, n-butyl acetate.

Abstract: m-Xylene is difficult to separate from p-xylene or o-xylene by conventional distillation or rectification because of the close proximity of their boiling points. m-Xylene can be readily separated from p-xylene or o-xylene by using extractive distillation in which the agent is an alcohol. Typical examples of effective agents are: for m-xylene from o-xylene, 1-octanol and cyclododecanol; for p-xylene from m-xylene, diisobutyl carbinol and cyclododecanolphenethyl alcohol mixture.

Abstract: Cycloalkanes, preferably cyclohexane and/or cyclopentane, are separated from close-boiling alkanes by extractive distillation employing as solvent a mixture of (a) at least one N-hydroxyalkyl-2-pyrrolidone, preferably N-(.beta.-hydroxyethyl)-2-pyrrolidone, and (b) at least one saturated C.sub.5 -C.sub.9 alcohol, preferably cyclohexanol.

Abstract: 4-Methyl-2-pentanone cannot be easily separated from formic acid by distillation because of the closeness of their boiling points. 4-Methyl-2-pentanone can be readily removed from formic acid by extractive distillation using dimethylamides. Typical effective agents are dimethylformamide; dimethylacetamide and acetyl salicyclic acid; dimethylacetamide, heptanoic acid and methyl benzoate.

Abstract: The lower lactate esters are difficult to separate one from another by conventional distillation or rectification because of the close proximity of their boiling points. Lactate esters can be readily separated from each other by extractive distillation. Typical examples of effective agents are: for methyl lactate from ethyl lactate, ethylene glycol; ethyl lactate from isopropyl lactate, diethylene glycol; isopropyl lactate from n-propyl lactate, isophorone; n-propyl lactate from butyl lactate, 2-hydroxyacetophenone.

Abstract: 2-Methyl butanol-1 cannot be completely removed from 2-methyl butanol-1-pentanol-1 mixtures by distillation because of the proximity of their boiling points. 2-methyl butanol-1 can be readily removed from mixtures of these alcohols by using extractive distillation in which the extractive agent is a mixture of aromatic carboxylic acids or aromatic carboxylic esters. Typical examples of effective agents are: benzoic acid, ethyl salicylate and salicylic acid; methyl benzoate, methyl p-hydroxy benzoate and phenyl salicylate.

Abstract: 3-Methyl-2-butanone cannot be separated from formic acid by distillation because of the presence of the maximum boiling azotrope. 3-Methol-2-butanoe can be readily removed from formic acid by extractive distillation using sulfolane. Typical effective agents are: sulfolane and ethylene glycol diacetate; sulfolane, m-toluic acid and anisole.

Abstract: Cycloalkanes (preferably cyclopentane and/or cyclohexane) are separated from close-boiling alkanes by extractive distillation employing as solvent a mixture of (a) at least one N-mercaptoalkyl-2-pyrrolidone (preferably N-mercaptoethyl-2-pyrrolidone) and (b1) at least one N-alkyl-2-pyrrolidone (preferably N-methyl-2-pyrrolidone) and/or (b2) at least one saturated C.sub.5 -C.sub.9 alcohol (preferably cyclohexanol).

Abstract: A mixture of (a) at least one saturated C5-C9 alcohol (preferably cyclohexanol) and (b) at least one sulfolane (preferably unsubstituted sulfolane, cyclotetramethylene sulfone) is used as solvent in the extractive distillation of a feed mixture of cycloalkane(s) in particular cyclohexane) and close-boiling alkane(s). A novel composition of matter contains (a) and (b), as defined above, and optionally also (c) water.

Abstract: A method of inhibiting fouling in distillation towers, overhead lines, reflux lines, and condensers operating in a process to manufacture and purify epichlorohydrin. This method resides in treating process streams entering or exiting such towers, lines and condensers, including feed streams, reflux streams, gaseous or liquid overhead streams, with an effective antifouling amount of a C.sub.3 -C.sub.9 linear or branched alkyl substituted catechol, or mixtures thereof.

Abstract: n-Propanol and t-amyl alcohol cannot be separated from each other by distillation because of the proximity of their boiling points. n-Propanol can be readily separated from t-amyl alcohol by using extractive distillation in which the extractive agent is a higher boiling organic compound or a mixture of two or more of these. Typical examples of effective agents are: methyl salicylate; benzyl benzoate and hexahydrophthalic anhydride; methyl salicylate, benzoic acid and hexahydrophthalic anhydride.

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 the extractive agent is a benzoic acid derivative mixed with certain higher boiling organic compounds. Examples of effective agents are: o-toluic acid and heptanoic acid; 2-benzoylbenzoic acid and methyl salicylate; p-hydroxybenzoic acid, pelargonic acid and 2-hydroxyacetophenone.

Abstract: An extractive distillation process for separating at least one cycloalkane from at least one close-boiling alkane employs as solvent a mixture of (a) at least one saturated C5-C9 alcohol (preferably cyclohexanol) and (b) at least one glycol compound (preferably tetraethylene glycol).

Abstract: Formic acid cannot be easily removed from acetic acid by distillation because of the closeness of their vapor pressures. Formic acid can be readily removed from acetic acid by extractive distillation. Typical extractive distillation agents are acetyl salicylic acid and butyl benzoate; acetyl salicylic acid and ethylene carbonate.

Abstract: Diastereomers can be separated with good industrial success with the aid of extractive distillation. The separation process is characterized in that an auxiliary which changes the partial pressure of the various diastereomers to be separated to a different degree and thus allows easier separation of the diastereomers by distillation is added during the distillation. Using the present process diastereomic cis/trans-permetric acid methyl esters and mixtures of menthol and isomenthol can be separated with isolation of 99% pure product.

Abstract: Dioxane cannot be completely removed from dioxane and formic acid mixtures by distillation because of the presence of the maximum azeotrope. Dioxane can be readily removed from dioxane - formic acid mixtures by extractive distillation in which the extractive agent is dimethylsulfoxide, either alone or admixed with certain high boiling organic compounds. Examples of effective agents are dimethylsulfoxide; DMSO and octanoic acid; DMSO, neodecanoic acid and methyl salicylate.

Abstract: Dioxane cannot be completely removed from dioxane and acetic acid mixtures by distillation because of the presence of the maximum azeotrope. Dioxane can be readily removed from dioxane-acetic acid mixtures by extractive distillation in which the extractive agent is dimethylsulfoxide, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are dimethylsulfoxide; DMSO and octanoic acid; DMSO, hexanoic acid and isophorone.

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 dimethylsulfoxide, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are dimethylsulfoxide; DMSO and octanoic acid; DMSO, hexanoic acid and isophorone.

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 the extractive agent is ethylene carbonate or propylene carbonate, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are ethylene carbonate and heptanoic acid; propylene carbonate, benzoic acid and isophorone; propylene carbonate, heptanoic acid and 2-hydroxyacetophenone.

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; methyl benzoate plus benzophenone; methyl benzoate, butyl benzoate and dimethylsulfoxide.

Abstract: Impure formic acid cannot be completely removed from formic acid-water-impurity mixtures by distillation because of the presence of the maximum azeotrope between formic acid and water. Formic acid can be readily removed from mixtures containing it, water and impurities of the ether, ester, ketone or diketone type by using extractive distillation in which the extractive agent is a higher boiling oxygenated, nitrogenous or sulfur containing organic compound or a mixture of these. Examples of effective agents are adiponitrile; sulfolane and salicyclic acid; dimethylformamide, N,N-dimethylacetamide and ethylene glycol ethyl ether acetate.

Abstract: Isopropanol and t-butanol cannot be separated from each other by distillation because of the proximity of their boiling points. Isopropanol can be readily separated from t-butanol by using extractive distillation in which the extractive agent is a higher boiling oxygenated organic compound or a mixture of two or more of these. Typical examples of effective agents are: methyl benzoate; methyl benzoate and hexahydrophthalic anhydride; phthalic anhydride, hexahydrophthalic anhydride and methyl benzoate.

Abstract: Ethanol and isopropanol cannot be separated from each other by distillation because of the proximity of their boiling points. Ethanol can be readily separated from isopropanol by using extractive distillation in which the extractive agent is a higher boiling oxygenated organic compound or a mixture of two or more of these. Typical examples of effective agents are: methyl salicylate; salicylic acid and hexahydrophthalic anhydride; salicylic acid, hexahydrophthalic anhydride and methyl benzoate.

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 dimethylformamide; dimethylformamide and 1,4-butanediol; dimethylformamide, adiponitrile and dihexyl phthalate.

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 adiponitrile or a mixture of it with certain high boiling organic compounds. Typical examples of effective agents are: adiponitrile; adiponitrile and 1,4-butanediol; adiponitrile, ethylene carbonate and benzyl alcohol.

Abstract: n-Hexyl alcohol cannot be completely removed from n-hexyl acetate- n-hexyl alcohol - water mixtures by distillation because of the presence of the minimum ternary azeotrope. n-Hexyl alcohol can be readily removed from mixtures containing it, n-hexyl acetate and water by using extractive distillation in which the extractive distillation agent is a benzoate or a mixture of benzoates with higher boiling organic compounds. Typical examples of effective agents are benzyl benzoate; methyl benzoate and adiponitrile; ethyl benzoate, benzyl benzoate and methyl salicylate.

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 a mixture polychloro aromatic compounds. Typical examples of effective agents are 2,3,4,6-tetrachlorophenol and p-dichlorobenzene; dimethyltetrachloroterephthalate, 2,3,4,6-tetrachlorophenol and 1,2,4,5-tetrachlorobenzene; 2,4,5-trichlorophenol, benzene hexachloride, o-dichlorobenzene and dioctyl phthalate.

Abstract: Isopropanol cannot be completely removed from isopropanol - isopropyl acetate - water mixtures by distillation because of the presence of the minimum ternary azeoptrope. Isopropanol can be readily removed from mixtures containing it, isopropyl acetate and water by using extractive distillation in which the extractive agent is a higher boiling benzoate or nitro paraffin. Typical examples are methyl benzoate; methyl benzoate and nitromethane; butyl benzoate, nitromethane and nitroethane.

Abstract: Water cannot be completely removed from ethanol by distillation because of the presence of the minimum azeotrope. Ethanol can be readily dehydrated by using extractive distillation in which the water is removed as overhead product and the ethanol and extractive agent as bottoms and subsequently separated by conventional rectification. Typical examples of suitable extractive agents are hexahydrophthalic anhydride; methyl tetrahydrophthalic anhydride and pentanol-1; trimellitic anhydride, ethyl salicylate and resorcinol.

Abstract: Water cannot be completely removed from ethanol by distillation because of the presence of the minimum azeotrope. Ethanol can be readily dehydrated by using extractive distillation in which the water is removed as overhead product and the ethanol and extractive agent as bottoms and subsequently separated by conventional rectification. Typical examples of suitable extractive agents are methyl benzoate; trimellitic anhydride and methyl benzoate; dipropylene glycol dibenzoate, ethyl salicylate and resorcinol.

Abstract: Benzene is virtually impossible to separate from similar close boiling non-aromatic hydrocarbons by conventional rectification or distillation. Benzene can be readily separated from similar boiling non-aromatic hydrocarbons by using extractive distillation in which the extractive agent is a mixture of benzoic acid, maleic anhydride and/or phthalic anhydride plus a suitable solvent. A typical mixture comprises phthalic anhydride, maleic anhydride and adiponitrile.

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: This invention is directed to the use of mixtures of a polymerization inhibitor in the distillation of readily polymerizable vinyl aromatic monomers and more specifically to the use of mixtures containing 2,6-dinitro-4-halophenols as polymerization inhibitors for vinyl aromatic monomers such as styrene and vinyl benzenes. The invention comprises the process of subjecting the vinyl aromatic monomers to distillation temperatures in the presence of mixtures containing 2,6-dinitro-4-halophenols to inhibit polymerization.

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: Disclosed is a process for the distillation of readily polymerizable vinyl aromatic compounds and a new polymerization inhibitor therefor. The process comprises subjecting a vinyl aromatic compound to elevated temperatures in a distillation system in the presence of a new polymerization inhibitor comprising 2,6-dinitro-p-cresol. Also disclosed is a distillation method and apparatus for use with this inhibitor.

Abstract: This invention is directed to the use of a polymerization inhibitor in the distillation of readily polymerizable vinyl aromatic monomers and more specifically to the use of mixtures of 2,6-dinitro-4-ethyl-phenol as a polymerization inhibitor for vinyl aromatic monomers such as styrene and vinyl benzenes. The invention comprises the process of subjecting the vinyl aromatic monomers to distillation temperatures in the presence of mixtures of 2,6-dinitro-4-ethyl-phenol and 2,6-dinitro-paracresol to prevent polymerization.

Abstract: The present invention provides an improvement in methods for preparing and processing ethylenically unsaturated aromatic monomer. The improvement comprises employing 3,5-dinitrosalicylic acid or a derivative or isomer thereof as a process inhibitor. The process inhibitor is present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2,000 ppm, and most preferably about 500 to 1,000 ppm.

Abstract: A process is disclosed for separating low molecular weight alcohols, especially ethanol, from aqueous mixtures. The process involves subjecting alcohol-water mixtures to extraction and/or extractive distillation procedures. Extractive solvents useful for the process of this invention include phenols having at least six carbon atoms and a boiling point between about 180.degree. C. and about 350.degree. C.

Abstract: An extractive distillation process is provided for the separation of phenol and/or cresol from mixtures with high boiling oxygenated compounds such as alkanols, alkanones, cycloalkanones, cycloalkanols, aryl alcohols, aryl ketones or mixtures thereof that have a boiling point of at least about 175.degree. C. The process involves distilling the phenol and/or cresol-high boiling oxygenated compound mixture in the presence of at least one extractive solvent comprising a substituted phenol and/or substituted cresol that has a boiling point between about 195.degree. C. and about 400.degree. C.

Abstract: The present invention provides an improvement in methods for preparing and processing ethylenically unsaturated aromatic monomer. The improvement comprises employing 3,5-dinitrosalicylic acid as a process inhibitor. The DNSA is present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2000 ppm, and most preferably about 500 to 1000 ppm.

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: Disclosed is a method of distilling readily polymerizable vinyl aromatic compounds such as styrene, .alpha.-methyl styrene, vinyl toluenes and divinylbenzenes wherein 2,2-bis(3,5-dinitro-4-hydroxy-phenyl)propane is used as a polymerization inhibitor. The invention is particularly useful for the distillation of divinylbenzene.