Abstract: The separation of alkadienes from close-boiling alkenes by extractive distillation employs as solvent either N-(.beta.-mercaptoethyl)-2-pyrrolidone alone, or a mixture of N-(.beta.-mercaptoethyl)-2-pyrrolidone and either N-methyl-2-pyrrolidone or cyclohexanol, or a mixture of cyclohexanol and tetraethylene glycol. The separation of cycloalkadines from close-boiling alkadienes by extractive distillation employs N-(.beta.-mercaptoethyl)-2-pyrrolidone as solvent.

Abstract: The separation of alkadienes from close-boiling alkenes by extractive distillation employes as solvent N-methyl-2-thiopyrrolidone, alone or in admixture with unsubstituted sulfolane (cyclotetramethylene sulfone), or a mixture of unsubstituted sulfone and N-methyl-2-pyrrolidone. The separation of cycloalkadienes from close-boiling alkadienes by extractive distillation employs N-methyl-2-thiopyrrolidone as solvent.

Abstract: The higher boiling ketone isomers are difficult to separate one from another by conventional distillation or rectification because of the close proximity of their boiling points. Ketone isomers can be readily separated from each other by extractive distillation. Typical examples of effective agents are: for 3-pentanone from 2-pentanone, dipropylene glycol; 3-hexanone from 2-hexanone, butoxypropanol; 3-heptanone from 2-heptanone, 50% ethylene glycol--50% butoxypropanol; 3-octanone from 2-octanone, ethylene glycol diacetate.

Abstract: An extractive distillation agent consisting essentially of ethylene carbonate, propylene carbonate or a mixture thereof is fed to an extractive distillation column used for the distillation of propylene oxide contaminated with water to obtain an overhead distillate fraction consisting of essentially anhydrous propylene oxide, and a heavier bottoms distillation fraction containing substantially all of the extraction distillation solvent and water introduced into the distillation column.

Abstract: Aromatic hydrocarbons containing 6-10 carbon atoms per molecule are separated from close-boiling olefinic hydrocarbons by extractive distillation employing as solvent either N-methyl-2-thiopyrrolidone alone, or a mixture of N-(.beta.-mercaptoethyl)-2-pyrrolidone and N-methyl-2-thiopyrrolidone, or a mixture of N-(.beta.-mercaptoethyl)-2-pyrrolidone and N-methyl-2-pyrrolidone.

Abstract: p-Cymene and p-menthane are difficult to separate one from another by conventional distillation or rectification because of the close proximity of their boiling points. p-Cymene and p-menthane can be readily separated one from another by using azeotropic or extractive distillation. Typical examples of effective agents, for azeotropic distillation: diethyelene glycol ethyl ether, 1-pentanol and isobutanol; for extractive distillation: butyl benzoate, undecyl alcohol and methyl benzoate.

Abstract: 4-Methyl-2-pentanone cannot be easily separated from acetic acid by distillation because of the closeness of their boiling points. 4-Methyl-2-phentanone can be readily removed from acetic acid by extractive distillation. Typical effective agents are dimethylformamide (DMFA); DMFA and m-toluic acid; DMFA, p-toluic acid and isobutyl heptyl ketone.

Abstract: p-Xylene is difficult to separate from m-xylene by conventional distillation or rectification because of the close proximity of their boiling points. p-Xylene can be readily separated from m-xylene by using extractive distillation in which the agent is an ester. Typical examples of effective agents are butyl butyrate, methyl caproate and methyl heptanoate.

Abstract: An extractive distillation process for separating at least one C.sub.4 -C.sub.10 alkene (monoolefin) from at least one close-boiling alkane (paraffin) employs as solvent a mixture of (a) at least one N-alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone and either (b1) at least one sulfolane compound (preferably cyclotetramethylene sulfone) or (b2) at least one glycol compound (preferably tetraethylene glycol) or both (b1) and (b2).

Abstract: Cyclohexane cannot be readily separated from cyclohexene by conventional distillation or rectification because of the close proximity of their boiling points. Cyclohexane can be separated from cyclohexene by azeotropic or extractive distillation. Typical examples of effective agents are: for azeotropic; ethylene glycol methyl ether and n-butanol; for extractive; propylene glycol methyl ether and diacetone alcohol.

Abstract: An extractive distillation process for separating at least one aromatic hydrocarbon from at least one close-boiling alkane employs as solvent a mixture of (a) at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone and (b) at least one sulfolane, preferably cyclotetramethylene sulfone.

Abstract: An extractive distillation process for separating at least one C.sub.4 -C.sub.10 alkene (monoolefin) from at least one close-boiling alkane employs solvent at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone, optionally in admixture with at least one N-alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone.

Abstract: A process for the purification of crude benzoic acid obtained by the catalytic oxidation of toluene in the liquid phase, which is contaminated with impurities including phthalic acid and benzylbenzoate, the process involves distilling the crude benzoic acid in a first distillation in the presence of an aliphatic amine or a mixture of aliphatic amines of the formulaHNR.sup.1 R.sup.2whereinR.sup.1 represents hydrogen or a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms andR.sup.2 represents a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms,and/or the salts of these amines, recovering from this distillation (a) a purified benzoic acid and (b) a benzylbenzoate containing residue, working up the residue by a second distillation and chlorinating the distillate resulting from this second distillation to give a benzoylchloride virtually free of benzonitrile.

Abstract: Extractive distillation processes for separating aromatic hydrocarbon(s) or cycloalkane(s) or alkene(s) from close-boiling alkane(s) are carried out with a solvent including at least one N-alkyl-2-thiopyrrolidone compound, preferably N-methyl-2-thiopyrrolidone. Optionally, the solvent additionally contains a cosolvent, preferably tetraethylene glycol or N-(.beta.-mercaptoethyl)-2-pyrrolidone or unsubstituted sulfolane.

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 higher boiling ester. Typical examples of effective agents are diisononyl adipate, glycerol triacetate and dimethyl phthalate.

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 mono carboxylic acid mixed with certain high boiling organic compounds. Examples of effective agents are: hexanoic acid and butyl benzoate; octanoic acid and nitrobenzene; heptanoic acid, benzyl benzoate and pelargonic acid.

Abstract: The present invention provides a process to recover esters of mercapto acids from solutions containing water by mixing an extraction mixture comprising cycloalkane, arene, and an aqueous inorganic salt solution with an ester of mercapto acid and water solution followed by separating and distilling the resultant organic phase to recover the ester of mercapto acid.

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: 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: A process for separation of components of a mixture of more than one organic substance or of a mixture of at least one organic substance and water by extraction using a supercritical fluid as an extractant. During the extraction an extraction aid having a higher affinity with an unextractable component of the mixture than with an extractable component of the mixture is present. Also disclosed is an apparatus for carrying out this process.

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: 4-Methyl-2-pentanone cannot be easily separated from formic acid or acetic acid by distillation because of the closeness of their boiling points. 4-Methyl-2-pentanone can be readily removed from formic acid or acetic acid by extractive distillation. Typical effective agents are sulfolane; sulfolane and heptanoic acid; sulfolane, azelaic acid and ethylene glycol diacetate.

Abstract: A mixture of (a) at least one N-alkyl-2-pyrrolidone (preferably N-methyl-2-pyrrolidone) and (b) at least one sulfolane (preferably unsubstituted sulfolane) is used as solvent in the extractive distillation of feed mixture of cycloalkane(s) (in particular cyclohexane) and close-boiling alkane(s).

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 dimethylformamide, dimethylacetamide or these with certain high boiling organic compounds.

Abstract: In a process for the production of methyl acetate from methanol and glacial acetic acid involving countercurrently flowing acetic acid and methanol through a single reactive distillation column having an extractive distillation section and a methyl acetate/acetic acid rectification section to obtain methyl acetate in the presence of an acidic catalyst, the improvement which comprises producing ultra high purity methyl acetate by the additional step of introducing acetic anhydride and a salt-free acid catalyst into the reactive distillation column between the extractive distillation section and the methyl acetate/acetic acid rectification section.

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: Vinyl acetate cannot be easily removed from ethyl acetate by distillation because of the closeness of their boiling points. Vinyl acetate can be readily separated from ethyl acetate by means of extractive distillation. Typical effective agents are formic acid, formamide and formic acid-formamide mixture.

Abstract: This is a method of reducing zirconium chloride to a metal product by introducing zirconium chloride into a molten salt bath containing at least one alkali metal chloride and at least one alkaline earth metal chloride; and electrochemically reducing alkaline earth metal chloride to a metallic alkaline earth metal in the molten salt bath, with the reduced alkaline earth metal reacting with the zirconium chloride to produce zirconium metal. By using this electrochemical-metallothermic reduction, zirconium metal is produced and insoluble subchlorides of zirconium in the metal product are generally avoided.Preferably, the molten salt in the molten salt bath consists essentially of a mixture of lithium chloride, potassium chloride, magnesium chloride and zirconium or hafnium chloride.

Abstract: This invention relates to a process for producing an olefin product having an enhanced alpha olefin content from an olefin feedstock containing internal olefins or a mixture of internal and alpha olefins which includes:(a) contacting the feedstock with an anthracene and a double-bond isomerization catalyst at a temperature ranging from about 150.degree. to about 275.degree. C. to form an olefin adduct with anthracene,(b) separating the adduct from the product of step (a),(c) heating the separated adduct at a temperature ranging from about 250.degree. to about 400.degree. C. to produce anthracene and an olefin product enhanced in alpha olefin content over the alpha olefin content of the feedstock, and(d) separating anthracene from the product of step (c) to produce the product enhanced in alpha olefin.Linear olefins are a preferred feedstock.

Abstract: Removal of aluminum and iron impurities is accomplished using an absorbing column containing potassium or sodium chloride, producing an aluminum and iron chloride-rich bottoms product and purified Zr(Hf)Cl.sub.4 vapor at the top of the column. This invention is a continuous process for removing impurities of iron or aluminum chloride or both from vaporous zirconium chloride (or hafnium chloride or a mixture thereof). When iron is being removed from zirconium tetrachloride using potassium chloride, the process comprises: introducing impure zirconium chloride vapor into a middle portion of an absorbing column containing a potassium chloride-containing molten salt phase, the molten salt phase absorbing the iron chloride impurity to produce a zirconium chloride vapor stripped of iron chloride in the top portion of the column; introducing potassium chloride into a top portion of the column; controlling the top portion of the column to between 300.degree.-375.degree. C.

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: Vinyl acetate cannot be easily removed from ethyl acetate by distillation because of the closeness of their boiling points. Vinyl acetate can be readily separated from ethyl acetate by means of extractive distillation using certain glycols or glycol ethers. Typical effective agents are 2-methyl -2,4-pentanediol, 1,3-butanediol, ethylene glycol methyl ether and diethylene glycol ethyl ether.

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: Improvements are described to a process in which the extractive distillation separation of zirconium or hafnium may be accomplished using mixtures of fused alkali metal or alkali metal and alkaline earth chlorides as the solvent. The solvent composition is adjusted to provide a low-melting eutectic, permitting recirculation of the stripped solvent in the liquid phase, as well as reducing the temperature required for thermal stripping (reducing the corrosivity of the fluid). Stripping of the bottoms is accomplished at least partially by direct electrolysis of the bottoms stream, producing the zirconium-free salt recycle stream to be transferred to the top of the column, and at least partially eliminating the need for chemical reduction of the tetrachlorides to metal (a costly process generating undersirable waste streams). Regeneration of the reflux is accomplished in a presurized condenser system, of one or more stages, with all material transport to be done in either the liquid or vapor states.

Abstract: This is a method for molten salt systems related to distillation for zirconium-hafnium separation and prevents buildup of iron chloride by electrochemically reducing iron from the molten salt to give very low levels of iron chloride in the distillation column, to reduce corrosion, improve the product and, in some cases, to allow the molten salt system to be run continuously. The improvement comprises electrochemical purification of molten salt containing zirconium-hafnium chloride either, prior to introduction of the zirconium-hafnium chloride into a distillation column, or after introduction, or both, to substantially eliminate iron chloride from the zirconium-hafnium chloride. The molten salt during the electrochemical purification consists essentially of a mixture of chlorides of alkali metals, alkaline earth metals, zirconium, hafnium, aluminum, manganese, and/or zinc.

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: 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: 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 N,N-dimethylacetamide or dimethylformamide, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are N,N-dimethylacetamide; dimethylformamide and heptanoic acid; N,N-dimethylacetamide, heptanoic acid and diethylene glycol diethyl ether.

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: An extractive distillation process for recovering trimethoxysilane from a trimethoxysilane-methanol mixture is provided using as the extractive solvent tetramethoxysilane.

Abstract: 2-Butanol cannot be completely removed from 2-butanol - t-amyl alcohol mixtures by distillation because of the proximitry of their boiling points. 2-Butanol can be readily removed from mixtures containing it and t-amyl alcohol by using extractive distillation in which the extractive agent is a higher boiling benzoate. Typical examples are methyl benzoate; methyl benzoate and salicylic acid; methyl benzoate, cinnamic acid and hexahydrophthalic anhydride.

Abstract: This is a molten salt extractive distillation process for separating hafnium from zirconium. It utilizes at least principally a ZnCl.sub.2 --Ca/MgCl.sub.2 molten salt solvent, and preferably ZnCl.sub.2 --Ca/MgCl.sub.2 in a near 95-15 mixture. The extraction column is preferably run about 380.degree.-420.degree. C. at about one atmosphere and stripping is preferably done at about 385.degree.-450.degree. C. utilizing an inert gas carrier.

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: This is a molten salt extractive distillation process for separating hafnium from zirconium. It utilizes at least principally a ZnCl.sub.2 -PbCl.sub.2 molten salt solvent, and preferably ZnCl.sub.2 -PbCl.sub.2 in a near eutectic or eutectic mixture. The extraction column is preferably run about 370.degree.-390.degree. C. at about one atomosphere and stripping is preferably done at 375.degree.-400.degree. C. utilizing an inert gas carrier.