Abstract: A process has been developed for the purification of expoxides containing carbonyl compounds as impurities wherein the carbonyl compound content is up to 2% by weight of epoxide. Purification is effected by treatment with compounds containing at least one NH.sub.2 group.

Abstract: Process for dehydrating aliphatic alcohols admixed with water wherein the alcohols-water mixture is subjected to a first fractionation in the presence of a selective solvent, giving a vapor effluent containing dehydrated light alcohols and a liquid phase containing heavy alcohols, water and the selective solvent, said liquid phase being subjected to a second fractionation giving as vapor effluent an hetero-azeotropic mixture of water and heavy alcohols and, as liquid effluent, the selective solvent, which is fed back, said hetero-azeotropic mixture being condensed and separated into:(a) a light phase of high alcohol content which is subjected to a third fractionation giving a vapor effluent which is fed back and dehydrated heavy alcohols as liquid effluent, and(b) a heavy phase which is subjected to a fourth fractionation giving a vapor effluent which is fed back and water as liquid effluent.

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

Abstract: The invention involves a process for substantially separating the components of mixtures of substances at least one of which is of low volatility while the other is of low or no volatility, the process using a compressed gas under supercritical conditions and an entrainer which increases the concentration of said mixture in the gaseous phase as well as the separation factor between the components to be separated. The process operates in two distillation zones the first of which substantially separates the components of low volatility in a process similar to a rectification process while the second distillation zone separates the top product of the first distillation zone from the gas with the aid of the entrainer which is condensed partially and in this state is passed in countercurrent to the gas carrying the separated component of low volatility.

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 50 to 99 percent by weight of a selective solvent boiling at from 140.degree. C. to 260.degree. C. and(b) from 1 to 50 percent by weight of an organic solvent boiling at from 45.degree. C. to 125.degree. C.

Abstract: A process for recovering pure benzene from hydrocarbon mixtures containing the same and non-aromatic compounds which are gaseous and difficultly condensible is described in which the feedstock is fed to an initial distillation column operated at atmospheric or sub-atmospheric pressure. Overhead comprising benzene and non-aromatics is obtained and a portion thereof condensed. The condensible material is in part returned to the distillation column and in part subjected to extractive distillation to recover pure benzene. Those components which did not condense, i.e. the non-condensible and difficultly condensible components and entrained aromatics are fed to a reflux vessel such as a scrubber, stripper, or the like for recovery of any benzene or other valuable components which might be soluble in a selective solvent and used for such recovery. The selective solvent can be the same solvent used for the extractive distillation.

Abstract: A process for isolating butadiene, with the aid of a selective solvent, from a C.sub.4 -hydrocarbon mixture which contains butadiene and small amounts of styrene and may contain oxygen, hydrocarbons more soluble than butadiene in the selective solvent and hydrocarbons less soluble than butadiene in the selective solvent, in which process the C.sub.4 -hydrocarbon mixture is separated by extractive distillation into a distillate which contains the less soluble hydrocarbons, a stream of butadiene and a stream containing the more soluble hydrocarbons, and in which a mixture of styrene and C.sub.4 -hydrocarbons is removed from the C.sub.4 -hydrocarbon mixture in a distillation zone upstream of the extractive distillation, the top product of the said distillation zone being fed to the extractive distillation.

Abstract: Chlorinated phenols, e.g. pentachlorophenol, are stabilized against degradation, including degradation to chlorinated dibenzo-p-dioxins, caused by heat and other adverse conditions, by combining with them stabilizing amounts of at least one stabilizer selected from the group consisting of high-boiling epoxides and epoxidized oils, drying oils, unsaturated fatty acids and unsaturated esters of fatty acids.

Abstract: Indene is separated from close boiling, olefinically unsaturated alkylaromatic compounds by extractive distillation. For example, indene is separated from trans-.beta.-methylstyrene, and from 2-, 3- and 4-methylstyrene by extractive distillation using 1-methyl-2-pyrrolidone as the extracting agent.

Abstract: A process of recovering an n-hexane product which is free from aromatic compounds by extractive distillation from a mixture of aromatic and non-aromatic compounds. The mixture is fed to and distilled in a first distillation column, from which a benzene-containing sump product and the overhead product consisting of non-aromatic compounds are withdrawn. The distillate is laterally withdrawn above the feeding point of the feed mixture and transferred to the upper portion of a second distillation column. The hexane cut is withdrawn as sump product from the second distillation column and fed to an extractive distillation column approximately in the middle thereof and is extracted in the extractive distillation column with a selective solvent which is fed above the feeding point of the hexane cut consisting of the sump product of the second distillation column. The sump product containing the selective solvent is withdrawn from the extractive distillation column and the overhead thereof vapors are condensed.

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 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 lower aliphatic carboxylic acid ester or carbonic acid ester boiling at from 30.degree. C. to 200.degree. C.

Abstract: A method of drying quaternary ammonium compounds for use as additives in the anhydrous anionic polymerization of 2-pyrrolidone is disclosed.The method consists of dissolving or suspending the quaternary ammonium compound in 2-pyrrolidone and distilling over, under reduced pressure, a portion of the 2-pyrrolidone whereby the water is removed.

Abstract: The separation of butadiene-1,3 from other C-4 hydrocarbons of lesser degree of unsaturation by extractive distillation with alkoxynitrile or aqueous alkoxynitrile as selective solvent is carried out with improved selectivity, without appreciable formation of butadiene-1,3 polymer and with consequent savings in energy by adding to the alkoxynitrile or aqueous alkoxynitrile an organic cosolvent which is dimethyl sulfoxide, sulfolane, butyrolactone, N-methyl pyrrolidone, morpholine, or trimethyl phosphate and/or an inhibitor which is 2,4-dinitrophenol or 2,4-dinitro-ortho-cresol. The organic cosolvent is present in the selective solvent composition in an amount of 5 to 30 percent by weight and the inhibitor in an amount of 0.05 to 0.6 percent by weight.

Abstract: Formation of butadiene-1,3 polymer during the extractive distillation of a C-4 hydrocarbon mixture to separate and purify butadiene-1,3 using a solvent composition in which an alkoxynitrile is present in a proportion of 50-99 percent by weight, is decreased through inclusion in the solvent of a synergistic combination of 2,4-dinitrophenol and phosphoric acid, each in a proportion of 0.05 to 0.5 percent by weight.

Abstract: There is disclosed an azeotropic distillation process for separating and recovering hexamethyl disiloxane (HMDO) from toluene in a spent liquor mixture. An HMDO azeotrope former, pyrrolidone, is added to the liquor. The pyrrolidine is added in an amount of at least about 1.81 parts by weight per 1.0 part by weight of HMDO. Preferably, it is added in excess, as about 2.7 to about 5.4 parts by weight of pyrrolidine per 1.0 part by weight of HMDO. The resulting azeotrope of HMDO and pyrrolidine is then separated by distillation from the liquor. The pyrrolidine may be subsequently recovered from the HMDO by extraction with water. Other HMDO azeotrope formers, such as tertiary butanol, may also be utilized.

Abstract: A method for separating benzene, toluene, xylenes and higher aromatics from admixtures containing them is disclosed, said method being based on the use of a solvent which is a 5-atom cyclic derivative of urea in which at least one of the nitrogen atoms is bound to an alkyl.Representative of this class of selective solvents is N,N'-dimethyl ethylene urea.Procedure details and examples are given.

Abstract: In order to prevent corrosion of the apparatus in extraction and extractive distillation processes where N-substituted morpholine is employed as the selective solvent an additive is added to the solvent which additive consists of (a) phosphoric acid, (b) a salt thereof, (c) a vanadium compound, (d) a molybdenum compound or (e) a mixture of two or more of these compounds, the addition being effected in an amount of about 0.005 to 0.02% by weight of the morpholine solvent.

Abstract: Unreacted urea and/or biuret contaminants in a cyanuric acid-inert solvent reaction product are removed by distilling the solvent therefrom at a temperature of from about 150.degree. C. to about 250.degree. C. and at a pressure of from about 70 to about 170 mm. of Hg. A distillate of said solvent containing the urea, biuret and a cyanuric acid reaction product is collected.

Abstract: A mixture of C.sub.4 -hydrocarbons is extractively distilled with sulfolane and acetone or methylethyl ketone as the selective solvent; the rich solvent containing 1,3-butadiene and vinylacetylene is stripped and a small quantity of the ketone is allowed to leave overhead. Thereby the further fractionation of the stripper overhead results in a very efficient separation of 1,3-butadiene and vinylacetylene.

Abstract: Dimethyl carbonate is obtained pure, from its solutions in methanol, by extractive distillation carried out with a temperature of from 60.degree. C. at the top to 250.degree. C. at the bottom of the column and employing, as the extractant, an aprotic organic liquid which is substantially inert toward dimethyl carbonate, boils at above 100.degree. C. at standard pressure, is miscible with dimethyl carbonate in all proportions and has a dielectric constant .epsilon. of from 4 to 90 and a dipole moment .mu. of from 1.5 to 5 Debye.

Abstract: A process for separating, by means of a selective solvent, a mixture of C.sub.

Abstract: A multi-stage process for the solvent extraction of isoprene or cyclopentadiene from a mixed feed stock containing the same, piperylene and C-5 saturated and olefinic hydrocarbons is disclosed wherein the feed stock is contacted with N-formyl morpholine and C-5 saturated and olefinic hydrocarbons are separated therefrom in a first stage, the solvent, piperylene and cyclopentadiene present in the feed stock are separated from the isoprene in a second stage, and the solvent is recovered and recycled to the second stage.

Abstract: Acetylenic hydrocarbons are removed from a C.sub.4 - or C.sub.5 - hydrocarbon mixture containing a C.sub.4 - or C.sub.5 - diolefin respectively. The feedstock (e.g. a C.sub.4 - or C.sub.5 - cut from an ethylene plant) is extractively distilled to remove paraffins and mono-olefins in the raffinate, using acetonitrile (ACN), dimethyl formamide (DMF), furfural, acetone, dimethylacetamide or N-methyl-2-pyrrolidone mixed with 0-12 weight percent water as the extraction solvent. The bottoms from this first extractive distillation is subjected to a second extractive distillation in which virtually acetylenes-free solvent is used. Isoprene is withdrawn as the distillate with substantially reduced acetylenes content. The bottoms of the second extractive distillation is split three ways. Two streams are handled conventionally (recycle and heavies removal). The third is stripped free of acetylenes so that it may be used as solvent in the second extractive distillation.

Abstract: A method for the partial or total separation by extractive distillation of C.sub.1 to C.sub.3 clorinated aliphatic hydrocarbons from mixtures of at least two such chlorinated hydrocarbons. The mixture of the chlorinated hydrocarbons is distilled in the presence of one or more other organic compounds having a boiling temperature higher than the substances to be separated, and selected from the group comprising saturated polyols, ethylene carbonate, propylene carbonate, dimethyl formamide, furfural, N-methylpyrrolidone, cyclohexanone, dimethylsulfoxide and, preferably, sulfolane and alkylsulfolanes in which the alkyl group is C.sub.1 or C.sub.2 ; use of this method for the separation of mixtures containing or essentially consisting of trichlorethylene and 1,2-dichloroethane.

Abstract: This invention relates to a process of inhibiting or preventing fouling (i.e., preventing the adhesion of deposits from hydrocarbon on surfaces) at elevated temperatures which comprises adding to hydrocarbon an antifouling (preventing) amount of an organo-sulfur compounds having a high sulfur content. In the preferred embodiment, the organo-sulfur compound has at least 5% sulfur. An embodiment is a heterocyclic compound, a dithiole-thione. These organo sulfur compounds are particularly effective at elevated temperatures of at least about 500.degree. F.

Abstract: A process is described for improving the synthesis of 4-oxocapronitrile by adding an inert solvent to the atmospheric pressure distillation of the reaction mixture so that the temperature of said distillation is maintained below about 195.degree. C.

Abstract: Copper is processed via solutions of copper salts, both cupric and cuprous, in acidified aqueous solutions containing organic nitriles. Methods of producting solutions of cuprous salts include reduction of cupric salts and oxidation of copper and copper sulphides. Solutions of cuprous salts are thermally or electrochemically disproportionated to produce copper and solutions of cupric salts.

Abstract: Process for recovering highly pure aromatic substances from mixtures of hydrocarbons which contain in addition to the aromatic substances, large amounts of non-aromatic substances by liquid-liquid extraction in combination with an after arranged extractive distillation whereby the liquid-liquid extraction of the starting hydrocarbon mixture is carried out under such conditions that the resulting extract contains substantially the total amount of the aromatic substances and a portion of the non-aromatic substances, introducing this extract into an after arranged extractive distillation for further separating said extract whereby the sump product (extract phase) formed is drawn off and introduced into an after arranged distillation column where it is separated into an aromatic and a solvent fraction, while the head product of the extractive distillation (raffinate phase) is reintroduced into the bottom of the extractor for liquid-liquid extraction thereof, wherein there is used in both of the extracting stages,

Abstract: Formic acid is purified by extractive distillation of its aqueous solutions using a basic extractant, followed by distillation of the bottom mixture first obtained, the extractant used being N-formylmorpholine.

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: The present invention provides a process for purifying an organic isocyanate which comprises heating an organic isocyanate in admixture with a treating agent selected from the group consisting of a metal salt of mercaptobenzothiazol, a dithiocarbamic acid derivative, an alkyl-substituted phenol, a thio-bisphenol, and a triaryl phosphite at a temperature not lower than 100.degree. C and subsequently distilling the thusly treated mixture to recover a purified organic isocyanate.

Abstract: Disclosed is a process for the distillation of readily polymerizable vinyl aromatic compounds which comprises subjecting such compounds to distillation conditions in the presence of an effective amount of a combination of phenothiazine and a phenolic compound, preferably tert-butylcatechol (TBC), as a polymerization inhibitor system in the presence of oxygen.

Abstract: Butadiene is produced in relatively pure form by an oxidative dehydrogenation process in which a crude butadiene stream comprising butadiene, butylenes, vinyl acetylene and propylene is first extractively distilled with an extractant consisting of a sulfolane/acetone mixture. From a purified stream consisting essentially of butadiene and vinyl acetylene, the vinyl acetylene in a second extractive distillation step is removed using a sulfolane/acetone mixture as the extractant to produce a pure butadiene stream.

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: A method of partially or totally separating chlorinated aliphatic C.sub.1 to C.sub.3 hydrocarbons from mixtures of at least two of the chlorinated hydrocarbons by extractive distillation.The mixture of the chlorinated hydrocarbons is distilled in the presence of one or more third organic compounds having a boiling point higher than that of the substances to be separated, selected from the group comprising methyl, ethyl, normal propyl and isopropyl mono and di-chloroacetates; benzyl alcohol; salicylaldehyde, benzaldehyde, n-heptanal, methylisobutylketone, tetramethylurea, .gamma.-butyrolactone; normal propyl, isopropyl, normal, secondary and tertiary butyl acetylacetates; diethyl oxalate, dimethyl succinate and preferably methyl and ethyl acetylacetates; acetic anhydride, N-formyl-morpholine, 2-chloro ethanol, hexamethylphosphotriamide, dimethyl sulphate and normal tributyl and triisobutyl phosphates.

Abstract: Hydrocarbons having different degrees of saturation are separated by extractive distillation using selective solvent comprising a mixture of dimethylsulfone, methylethylketone and sulfolane.

Abstract: Benzene is converted by reductive alkylation to cyclohexylbenzene; cyclohexylbenzene by oxidation and cleavage is converted into a mixture of cyclohexylbenzene, phenol and cyclohexanone; after removal of cyclohexylbenzene from this mixture, the remaining mixture consisting essentially of phenol and cyclohexanone is effectively separated into its components by extractive distillation with a sulfolane.

Abstract: A mixture of n-butane and acetone is effectively separated by liquid-liquid extraction or extractive distillation using a sulfolane as the extractive solvent.

Abstract: A multi-stage process for the solvent extraction of butadiene from a mixed feed stock containing butadiene, C-4 saturated and olefinic hydrocarbons and acetylenic compounds is disclosed wherein the feed stock is contacted with N-formyl morpholine and C-4 saturated and olefinic hydrocarbons are separated therefrom in a first stage and, in a second stage, the solvent and acetylenic compounds present in the feed stock are respectively separated from one another.

Abstract: An extractive distillation cosolvent comprising furfural-alicyclic or acyclic C.sub.5 -C.sub.8 ketone having a boiling point of 130.degree.-180.degree. C., for example cyclohexanone, gives 20% or more improved hydrocarbon solubility and provides a more efficient process for separation of C.sub.4 and C.sub.5 hydrocarbons of varying degrees of saturation.

Abstract: A diolefin (isoprene or butadiene) is separated from a mixture thereof with other hydrocarbons by feeding the mixture to an extractive distillation column at a point intermediate its ends and also feeding to that column, at a point adjacent its upper end, an imidazole derivative, such as N-methyl imidazole, which is a solvent for the diolefin, withdrawing substantially all of the other hydrocarbons from the upper end of the column and withdrawing the solvent, substantially all of the diolefin and the balance of the other hydrocarbons as bottom product from that first extractive distillation column. That bottom product is then fed to a second extractive distillation column, the diolefin is withdrawn from its upper end in substantially pure form, the balance of the other hydrocarbons are withdrawn in vapor phase and the solvent is withdrawn from the lower end of the second extractive distillation column for recycle to the first and second extractive distillation columns.

Abstract: Methods of reducing aqueous solutions of cupric sulfate to cuprous solutions by using organic nitrile compositions are disclosed. The particular nitrile used is acetonitrile and the reductant is sulphur dioxide. The method has application commercially to leaching ores containing oxidised copper to obtain cuprous ion solutions. Such solutions can be treated by electrochemical or thermal disproportionation methods to obtain very pure copper.

Abstract: Method of preparing cuprous sulfate and bisulfate solutions from materials containing copper and impurities by a leaching process are disclosed. The leaching composition contains sulfuric acid, cupric ions, water and an organic nitrile. The leaching composition may be used with copper sulfide ores in particulate form. The cuprous solutions resulting from the leaching can be treated by disproportionation methods to recover pure copper.

Abstract: Styrene of exceptional purity is separated from a mixture of hydrocarbons including it, xylenes, saturated and olefinic hydrocarbons and ethyl benzene by means of a two-step extractive distillation process through the use of a high boiling polar solvent such as N-formyl morpholine in admixture with an amount of water in the range of from 1% to 30% by weight.