Abstract: 3-Carene and limonene cannot be separated from each other by rectification because of the closeness of their boiling points. They are readily separated by azeotropic distillation. Effective agents are: cyclopentanol, 2-nitropropane, ethyl formate amyl acetate dimethyl carbonate, tetrahydrofuran, acetic acid and 2-amino-amethyl-1-propanol.

Abstract: Vinyl aromatic monomer polymerization methods utilizing a composition of 2,6-di-tert-butyl-4-methylphenol and a substituted benzoquinonediimide compound are disclosed. Preferably, the composition is employed in an amount of 1 part to 10,000 parts per million parts monomer during distillation of styrene.

Abstract: A method for accelerating the settling of finely divided solids in hydrocarbon fluids comprising adding to the hydrocarbon a sufficient settling amount of a polyacrylic acid adducted alkylphenol-formaldehyde resin alkoxylate compound. Preferably, the hydrocarbon is a fluid catalytic cracker slurry containing spent catalyst fines.

Abstract: Vinyl aromatic monomer polymerization methods utilizing a composition of 2,6-di-tert-butyl-4-methylphenol and a substituted benzoquinonediimide compound are disclosed. Preferably, the composition is employed in an amount of 1 part to 10,000 parts per million parts monomer during distillation of styrene.

Abstract: o-Xylene cannot be separated from p-xylene and m-xylene by conventional distillation or rectification because of the proximity of their boiling points. o-Xylene can be readily separated from mixtures of p-xylene and m-xylene by azeotropic distillation. Effective agents are 3-methyl-1-butanol, methyl propionate and 3-pentanone.

Abstract: Benzene is difficult to separate from cyclohexane or cyclohexene by conventional distillation or rectification because of the close proximity of their boiling points. Benzene can be readily separated from cyclohexane or cyclohexene by using extractive distillation. Effective agents are: for benzene from cyclohexane, methyl acetoacetate; for benzene from cyclohexene, ethyl acetoacetate.

Abstract: Derivatized molybdenum-sulfide dimers of the general formula [(C.sub.5 R.sub.5 Mo).sub.2 (.mu.-S).sub.4-x (.mu.-SR).sub.x ].sup.n are utilized in the solid state, incorporated in permselective membranes and in aqueous solution as chemical specific complexing agents in various separation processes.

Abstract: Derivatized molybdenum-sulfide dimers of the general formula [(C.sub.5 R.sub.5 Mo).sub.2 (.mu.-S).sub.4-x (.mu.-SR).sub.x ].sup.n are utilized in the solid state, incorporated in permselective membranes and in aqueous solution as chemical specific complexing agents in various separation processes.

Abstract: Benzene is difficult to separate from cyclohexane or cyclohexene by conventional distillation or rectification because of the close proximity of their boiling points. Benzene can be readily separated from cyclohexane or cyclohexene by using azeotropic distillation. Effective agents are: for benzene from cyclohexane, dimethoxymethane; for benzene from cyclohexene, methanol.

Abstract: 1-Decene is impossible to separate from 2-octanone by conventional distillation or rectification because the two compounds form a minimum boiling azeotrope. 1-Decene can be readily separated from 2-octanone by azeotropic distillation. Effective agents are 1-propanol, 2-ethoxyethanol, and methanol.

Abstract: 1-Decene is difficult to separate from 2-octanone by conventional distillation or rectification because of the proximity of their boiling points. 1-Decene can be readily separated from 2-octanone by azeotropic distillation. Effective agents are butyl propionate and 1-propanol.

Abstract: Benzene and other aromatics are separated from a stream of mixed hydrocarbons containing both aromatics and non-aromatics by extractive distillation with a solvent system containing dimethyl sulfoxide and optionally a co-solvent, preferably water, followed by distillation stripping of the aromatics from the enriched solvent system, and recycle of the lean solvent system to the extractive distillation step.

Abstract: Hexane is difficult to separate from vinyl acetate and/or methyl acrylate by conventional distillation or rectification because of the closeness of their boiling points. Hexane can be readily separated from vinyl acetate and/or methyl acrylate by extractive distillation. Effective agents are dimethylsulfoxide and dimethylformamide.

Abstract: alpha-Phellandrene is difficult to separate from d-limonene by conventional distillation or rectification because of the proximity of their boiling points. alpha-Phellandrene can be readily separated from d-limonene by azeotropic distillation. Effective agents are n-butyl acetate and sulfolane.

Abstract: For the separation of butenes and butanes by extractive distillation, a charge mainly containing butenes and butanes is contacted in an extractive distillation column under pressure with a first selective polar solvent, S1 (e.g., dimethyl formamide), the butanes being collected at the top. The solvent S1 containing the butenes and passing out at the bottom is mixed with a second solvent, S2, having a boiling point intermediate between that of butenes and that of the solvent S1, the mixture passing into a desorption column under pressure, where the butenes are collected at the top. The mixture of solvent S1 and S2 is separated in a purification column under atmospheric pressure, the solvent S2 passing out at the top is recycled to the desorption column, and the solvent S1 passing out at the bottom is recycled to the extractive distillation column.

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: For the separation of butanes and butenes by extractive distillation, a charge mainly containing butanes and butenes is contacted in an extractive distillation column under pressure with a polar solvent (e.g., dimethyl formamide), the butanes being collected at the head. The solvent containing the butenes passes into a second column under pressure, where the butenes are partly desorbed and collected at the head. The solvent still containing butenes is purified in a third column under atmospheric pressure and the solvent-containing vapor distillate thereof is returned, after compression, to the lower part of the second column.

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: Process for obtaining a pure hydrocarbon from a starting material containing the hydrocarbon including performing an extractive distillation of the starting material containing the hydrocarbon in an extractive distillation column using a solvent comprising an N-substituted morpholine having substituents with no more than seven carbon atoms; feeding the sump product of the extractive distillation column into a distillation separator column at an entry point in a center portion of the distillation separator column; distilling off the hydrocarbon from the top of the distillation separator column but advantageously returning a minor portion of it as a reflux; drawing off solvent from the sump of the distillation separator column; feeding the solvent drawn off from the sump of the distillation separator column into an evaporator to form a vapor in the evaporator at the pressure, p.sub.2, the pressure p.sub.2 in the evaporator being lower than the pressure p.sub.

Abstract: The separation by conventional distillation or rectification of methyl t-butyl ether from close boiling hydrocarbons is difficult because of the closeness of their vapor pressures. Methyl t-butyl ether can be readily separated from these by extractive distillation. Examples of effective agents are: from 1-pentene, dimethylsulfoxide; from cyclopentane, sulfolane and from n-pentane - cyclopentane mixtures, diethyl malonate.

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: Organic non-quaternary clathrate salts are useful for separating hydrocarbon feed streams into aromatics rich fraction and aromatics lean fraction. The organic non-quaternary clathrate salts are characterized by having cations containing less than 16 carbon atoms. Preferred salts are collidinium triflate and triethylammonium dihydroxybenzoate.

Abstract: A process for separating an aromatic from a mixture containing also nonaroma includes distilling off the nonaromatics from the top of the extractive distillation column as a top product, drawing the aromatic and selective solvent from the extractive distillation column and subsequently separating the selective solvent from the aromatic in a separator column. The extractive distillation column is provided with a separate top product distillation column for recovery of a selective solvent residue from the separated nonaromatics. The entry hydrocarbon mixture is heated prior to admission to the extractive distillation column by an indirect heat exchange with selective solvent drawn from the separator column and heated to a temperature of from 130.degree. to 150.degree. C.The heated entry hydrocarbon mixture is depressurized to form a liquid phase and a vapor phase and these phases are separately fed into the extractive distillation column, the vapor phase entry point being below the liquid phase entry point.

Abstract: A method of separation of aromates from hydrocarbon mixtures by extractive distillation with a selective solvent, includes introducing a hydrocarbon mixture into the extractive distillation column, distillating out non-aromate components of the introduced hydrocarbon mixture from a head of the extractive distillation column, withdrawing aromates together with a used solvent from a sump of the extractive distillation column and supplying to a driving-out column, separating the aromates from the solvent in the driving-out column, withdrawing the aromates as a head product and the solvent as a sump product from the driving-out column, reintroducing the withdrawn solvent into the extractive distillation column, the withdrawing of the solvent from the driving-out column including withdrawing only part of the solvent with a high temperature required for the complete aromate driving-out from the sump of the driving-out column, while a rest of the solvent with a certain aromate content and a lower temperature is with

Abstract: This invention is concerned with a process for separating isomers of disubstituted benzenes, wherein a mixture of isomers of disubstituted benzenes is contacted with a substituted cyclodextrin to form inclusion complexes, and desired isomers are recovered therefrom in a highly selective manner. The invention also provides substituted cyclodextrins suited for use in the process. Substituted cyclodextrins used in the process can be recovered and used repeatedly.

Abstract: An extractive distillation process for separation ethers (in particular methyl t-butyl ether or ethyl t-butyl ether), aliphatic hydrocarbons (in particular isobutane and/or isobutene) and alcohols (in particular methanol or ethanol) employs as solvent sulfolane(s) and/or dialkyl sulfone(s), or N-(.beta.-mercaptoalkyl)-2-pyrrolidone(s), or a mixture of N-alkyl-2-pyrrolidone(s) and either sulfolane(s) or glycol compound(s).

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: 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: Aromatic hydrocarbons containing 6-10 carbon atoms per molecule are separated from close-boiling olefinic hydrocarbons by extractive distillation employing N-(.beta.-hydroxyethyl)-2-pyrrolidone and/or cyclohexanol as solvent.

Abstract: A simultaneous recovery of pure benzene and pure toluene is performed by extractive distillation with N-formylmorpholine and/or other N-substituted morpholines whose substituents contain not more than seven C-atoms as a solvent. From the entry product by predistillation, a benzene fraction boiling in the region between 75.degree. and 85.degree. C. and a toluene fraction boiling in the region between 99.degree. and 111.degree. C. is separated. The benzene fraction is supplied in the lower part, and the toluene fraction is supplied in the upper part of the extractive distillation column separated by a chimney plate into two parts.

Abstract: 1,1,1-Trichloroethane cannot be completely separated from n-hexane by conventional distillation or rectification because of the minimum boiling azeotrope. 1,1,1-Trichloroethane can be readily separated from n-hexane by extractive distillation. Typical effective agents are: methyl isoamyl ketone, amyl acetate and isobutanol.

Abstract: An extractive distillation process for separatin at least one C.sub.4 -C.sub.10 alkene (monoolefin) from at least one close-boiling alkane employs a solvent mixture of (a) at least one saturated alcohol (preferably cyclohexanol) and either (b1) at least one sulfolane (preferably cyclotetramethylene sulfone) or (b2) at least one glycol compound (preferably tetraethylene glycol) or (b1)+(b2).

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: A mixture of xylene isomers or a mixture of a xylene isomer(s) and ethylbenzene is brought into contact with at least one specific substituted .alpha.-cyclodextrin to form an inclusion complex(es) of the substituted .alpha.-cyclodextrin with a xylene isomer or ethylbenzene included therein, from which the xylene isomer(s) and/or ethylbenzene is then extracted to isolate, or separate, the same. Inclusion-complexing agents usable in isolation, or separation, of the xylene isomer(s) and/or ethylbenzene are substitited .alpha.-cyclodextrin in the form of .alpha.-cyclodextrin having the hydrogen atom of at least one hydroxyl group thereof substituted with at least one member selected from the group consisting of a glucosyl group, a maltosyl group, maltooligosaccharide residues, a hydroxyethyl group, a hydroxypropyl group, a methyl group, a sulfonic group, alkylenesulfonic groups, and carboxyalkyl groups.

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: 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: 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 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 separating 2,6-dimethylnaphthalene form a 2,6-dimethylnaphthalene-containing mixture which comprises mixing said mixture with 2,4,7-trinitro-9-fluorenone to thereby form a complex, separating a solid matter containing said complex and decomposing the solid matter containing the same to thereby separate and collect an oil rich in the 2,6-dimethylnaphthalene. According to this process, 2,6-dimethylnaphthalene can be readily separated at a high selectivity. Further, the 2,4,7-trinitro-9-fluorenone can be readily recovered and reused as such.

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: A lubricating oil stock is extracted with N-methyl-2-pyrrolidone to yield a primary raffinate useful as a high VI lubricating base oil and a primary extract. The primary extract is mixed with antisolvent and chilled to yield a secondary raffinate. This secondary raffinate is sufficiently reduced in aromatics that it is solvent extracted to yield medium to high VI lubricating base oil.

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: Water is separated from an MEK toluene dewaxing solvent by pervaporation through a polyvinyl alcohol membrane (optionally containing polyacrylic acid) mounted on a polyacrylonitrile support layer.

Abstract: An extractive distillation process for separating at least one cycloalkane or aromatic hydrocarbon from at least one close-boiling alkane employs as solvent at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone, either alone or in admixture with about 0.1-10 weight-% water.A liquid-liquid extraction process for separating at least one cycloalkane or aromatic hydrocarbon from at least one alkane employs as solvent at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone, either alone or in admixture with about 0.1-10 weight-% water.

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 N-alkyl-2-pyrrolidone (preferably N-methyl-2-pyrrolidone) and (b) at least one glycol compound (preferably ethylene glycol or tetraethylene glycol) is used as solvent in the extractive distillation of a feed mixture of cycloalkane(s) (in particular cyclohexane) and close-boiling alkane(s).

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: The process for production of an aromate concentrate for use as a blending component for gasification fuel includes subjecting another feed hydrocarbon mixture to an extractive distillation using N-substituted morpholines as selective solvent in a extractive distillation column. Low-boiling non-aromates with a boiling range up to about 105.degree. C. practically completely and higher-boiling non-aromates with a boiling range between about 105.degree. and 160.degree. C. to a substantial extent are discharged as a raffinate from the top of the extractive distillation column. The extract bottoms from the extractive distillation are fed to a solvent stripping column where the solvent is at least partially recovered from other hydrocarbons. To eliminate condensation and polymerization products due to components with a boiling point over 170.degree. C.

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.