Abstract: Separation of benzene from cyclohexane by distillation in the presence of selected nitriles.

Abstract: In a process for producing acrylic acid which comprises contacting with water an acrylic acid-containing reaction product gas which has been obtained by the catalytic vapor phase oxidation of an olefinic compound of a general formula, CH.sub.2 .dbd.CHX, wherein X represents at least one group selected from the group consisting of CH.sub.

Abstract: Dienic and/or aromatic hydrocarbons are separated from hydrocarbon fractions employing known liquid-liquid extraction and/or extractive distillation procedures and at least one sulfonamide solvent conforming to the general formula ##STR1## wherein R', R" and 4'" can be linear or branched, saturated or unsaturated, aliphatic groups possessing from 1 to 18 carbon atoms, wherein two or three of groups R', R" and R'" can be identical, wherein one of the groups R" and R'" can be replaced with a hydrogen atom, and wherein at least one of groups R', R" and R'" is unsaturated.

Abstract: A process for completing the esterification of aliphatic carboxylic acids of 1 to 8 carbon atoms with aliphatic or cycloaliphatic alcohols of 3 to 10 carbon atoms at the boiling point of the alcohol in a column operated with bottom heating, the lower space of the column being free from fitments, the middle space being provided with a packing and the upper space being provided with a packing or other fitments, in which process the water of esterification is driven off at the top of the column by azeotropic distillation, the starting mixture is fed into the side of the column from 5 to 10 m above the liquid level, the ester formed is taken off as liquid from the column bottom, and the column is operated with flooding such that the liquid level is from 6 to 10 m, with the liquid mixture filling the lower column space, which is free from fitments, and the lower part of the packed layer above the said space.

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 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: Deposit formation in distillation units, particularly column reboiler units, associated with the separation and purification of dialkyl phosphorochloridothioates from a crude material containing oxygenated compound impurities, is inhibited by incorporating in the feed stock a minor proportion (generally about 0.05 to about 15.0 weight percent) of an acylated amine prepared by reacting a hydrocarbon-substituted succinic compound with an alkylene amine or a hydroxyalkyl-substituted alkylene amine.

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: 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: 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: Xylenes can by merely being contacted with air over a period of time or during storage at temperatures upward from 60.degree. C. develop from 55 to 60 ppm of tolualdehyde. Such tolualdehyde formation can be suppressed by dissolving in the xylene a small amount of thiodipropionic acid or a di(alkyl)ester thereof.

Abstract: Acetone produced as a by-product in the reaction of methyl acetate with carbon monoxide and hydrogen in the presence of a Group VIII noble metal catalyst and methyl iodide is recovered from the reaction mixture by supplying acetone to provide an acetone to methyl iodide molar ratio of at least 1:10 and distilling the mixture comprising methyl iodide, acetone and methyl acetate to separate substantially all of the methyl iodide and the supplied acetone and some of the methyl acetate from the remaining acetone and methyl acetate and thereafter separating the acetone from the methyl acetate.

Abstract: An improved method for separating an ester formed in a reaction mixture is disclosed. The method comprises controlling the ratio of organic acid and alcohol utilized and the removal of unreacted alcohol as an alcohol-ester azeotrope.

Abstract: The invention refers to an improved process for the recovery of the solvent and of the by-produced methylacetate in the synthesis of terephthalic acid, said synthesis being usually consisting of an oxidation of paraxylene with air, in the presence of a catalyst system composed by cobalt, manganese and bromine, in a solvent consisting of acetic acid, according to the equation (1):C.sub.6 H.sub.4 (CH.sub.3).sub.2 +3 O.sub.2 .fwdarw.C.sub.6 H.sub.4 (COOH).sub.2 =2 H.sub.

Abstract: Esters are treated with alkali metal borohydride to produce alcohols. Substantially constant boiling admixtures of: methanol/methyl heptafluorobutyrate, water/1,1-dihydroheptafluorobutanol, and water/methyl heptafluorobutyrate are described.

Abstract: An improved process for the manufacture of levulinic acid which comprises esterification of furfuryl alcohol in the presence of a different alcohol selected from unsubstituted primary and secondary carbon-chain or carbon-ring alcohols containing 1 to 10 carbon atoms in the presence of a small amount of acid as a catalyst, purification of the resulting levulinate ester by vacuum distillation of a mixture of the levulinate ester and a high boiling solvent and hydrolysis of the purified levulinate ester in the presence of water and a small amount of strong acid catalyst to yield levulinic acid-water mixture. The improvement resides in the purification being carried out prior to hydrolysis and in using a high boiling solvent in the purification step to prevent the formation of a solid resin.

Abstract: Esters are treated with alkali metal borohydride to produce alcohols. Substantially constant boiling admixtures of: methanol/methyl heptafluorobutyrate, water/1,1-dihydroheptafluorobutanol, and water/methyl heptafluorobutyrate are described.

Abstract: An azeotropic distillation is conducted by feeding a part of an entrainer to the lower region of an azeotropic zone in a distillation column.

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: Phenol-, cyclohexanone-, and cyclohexylbenzene-containing mixtures are extractively distilled to provide an overhead of cyclohexanone substantially free of phenol and cyclohexylbenzene and a bottoms containing phenol and cyclohexylbenzene, substantially free of cyclohexanone by employing a nitrile solvent.

Abstract: Process for separating benzene and/or toluene from mixtures thereof with saturated hydrocarbons, by extractive distillation using an aliphatic N-alkylamide as extraction solvent, comprising introducing in the distillation column, above the level of introduction of the extraction solvent, liquid water in an amount and under such conditions that said water is completely vaporized without substantially diluting the solvent, condensing the vapors discharged from the top of the column and dividing the resulting condensate into a phase of liquid saturated hydrocarbons, and a phase of water.

Abstract: A trisubstituted phosphate is employed as extractive distillation solvent in the separation of cumene and phenol.

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 method of separating proximate boiling-point hydrocarbons using solutions of monovalent copper salts in solvents, said solvents being alkyl-substituted amides and alkyl esters of phosphorus-containing acids having a P.dbd.O group, N-alkyl-substituted amides of carboxylic acids, N-alkyl-substituted lactams, dialkyl sulphoxides, alkoxynitriles and N-alkyl-substituted aminonitriles. The method can be used for separating hydrocarbons from small quantities of acetylene compounds and cyclopentadiene.Large quantities of acetylene compounds are separated from the mixture of proximate boiling-point hydrocarbons by contacting the mixture with said solvents containing no salts of monovalent copper.

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: Butadiene is recovered from a hydrocarbon fraction containing it together with butenes and acetylene hydrocarbons by introducing said fraction into a first extractive distillation column, feeding aqueous acetonitrile into said column above the introduction point of said fraction and extracting a vapor stream containing butadiene below said introduction point; feeding said vapor stream into a second extractive distillation column, feeding aqueous acetonitrile above the introduction point of said vapor stream and recovering a vapor stream consisting essentially of butadiene at the top of said second column; and rectifying this last vapor stream to recover pure butadiene.

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: Terephthalonitrile is separated from p-xylene containing solution by fractional distillation in the presence of p-tolunitrile, with the p-tolunitrile being present in the fractional distillation tower in an amount sufficient to solubilize the terephthalonitrile in all portions of the column at which the temperature in the column is below the melting point of tetephthalontrile, whereby terephthalonitrile can be recovered as a liquid. The solution generally includes p-xylene, benzonitrile, p-tolunitrile and terephthalonitrile and is separated from a terephthalonitrile production reaction effluent by direct contact quenching with an organic liquid containing p-tolunitrile.

Abstract: Phenol-, cyclohexanone-, and cyclohexylbenzene-containing mixtures are extractively distilled employing an organic carbonate to provide overhead of high purity cyclohexanone and a kettle product substantially free of cyclohexanone and containing phenol, the organic carbonate, and, when present in the mixture, cyclohexylbenzene.

Abstract: Phenol-, cyclohexanone-, and cyclohexylbenzene-containing mixtures are extractively distilled to provide overhead of cyclohexanone and a kettle product substantially free of cyclohexanone by employing an N,N-disubstituted amide. When substantially no cyclohexylbenzene is present in the mixture to be extractively distilled, the kettle product will be essentially composed of the amide and phenol.

Abstract: Phenol-, cyclohexanone-, and cyclohexylbenzene-containing mixtures are extractively distilled employing an N-substituted lactam to provide overhead a high purity cyclohexanone and a kettle product containing phenol, cyclohexylbenzene when it is present in the mixture treated, and the N-substituted lactam.

Abstract: Phenol-, cyclohexanone-, and cyclohexylbenzene-containing mixtures are extractively distilled to provide overhead of cyclohexanone and a kettle product containing phenol and, when present, cyclohexylbenzene by employing a trisubstituted phosphate agent or solvent.

Abstract: A method is disclosed for stabilizing vinylbenzyl chloride and vinyltoluene against violent decomposition in the presence of iron and chlorine at ambient and above ambient temperatures which comprises contacting the vinylbenzyl chloride or vinyltoluene with an amount of a Lewis base sufficient to inhibit the decomposition during the preparation, purification or storage of said vinylbenzyl chloride or vinyltoluene.

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

Abstract: A continuous process for the preparation of acrylic and methacrylic acid esters by conventional esterification, where sufficient substantially anhydrous product ester is added to the esterification reactor to satisfy the ester/alkanol and ester/water azeotropes, the low boiling azeotropes are recovered, thereby removing crude product ester, unreacted alkanol and water of esterification from the esterification reactor, while leaving substantially all the high-boiling unreacted acrylic or methacrylic acid in the reactor.

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: An improvement is described on a process for recovery of butadiene from a C.sub.4 hydrocarbon mixture additionally containing minor amounts of C.sub.5 saturated and unsaturated hydrocarbons, said hydrocarbon mixture being obtained as the overhead product of an initial hydrocarbon fractionation employed to separate larger quantities of C.sub.5 and heavier hydrocarbons from the hydrocarbon mixture, wherein the hydrocarbon mixture is subject to extractive distillation in the presence of a polar solvent e.g. acetonitrile, in which butadiene is separated from the fat solvent bottoms of extractive distillation by sequential low pressure flashing and stripping, followed by compression of the combined vapors of flashing and stripping with part of the compressed vapors being recycled as reboiled vapor to the extractive distillation and the remainder being again stripped at a higher pressure to recover butadiene therefrom. In this improved process, butadiene purification problems associated with carry over of C.sub.

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: Ethylene glycol or 1,2-propylene glycol contained in mixtures with lower carboxylate esters of the glycol are separated from such mixtures by fractional distillation of the mixtures with the addition to the lower portion of the distillation zone of aqueous formic acid and/or acetic acid.

Abstract: 1,1,1,3,3,3-Hexafluoroisopropyl trifluoroacetate is separated from a crude reaction mixture by adding fluorotrichloromethane to said mixture and subjecting the resulting composition to fractional distillation to fractionally distill an azeotrope consisting of said 1,1,1,3,3,3-hexafluoroisopropyl trifluoroacetate and said fluorotrichloromethane from the crude mixture.

Abstract: Phenol, cyclohexanone, and cyclohexylbenzene containing mixtures are extractively distilled to provide overhead of cyclohexylbenzene and cyclohexanone and a kettle product substantially free of cyclohexylbenzene by employing a dialkyl and/or a dicycloalkyl phthalate. Co-agents or modifiers, e.g., sulfolane, polyalkylene glycols, etc., are advantageously used in some instances.

Abstract: Phenol-cyclohexanone azeotrope, for example, resulting from the cleavage product of 1-phenylcyclohexylhydroperoxide resulting from the oxidation of cyclohexylbenzene, from which cyclohexylbenzene may have been separated, is subjected to an extractive distillation with a selective solvent essentially containing a diester of adipic acid, e.g. a dialkyl and/or a dicycloalkyl ester of adipic acid. Specifically disclosed is a separation of a cyclohexanone-phenol mixture employing di(2-ethylhexyladipate). The diesters up to and including diC.sub.14 are referenced.

Abstract: Recovery of pure propylene oxide from propylene oxide which is contaminated by C.sub.6 hydrocarbons and methyl formate, by distillation with the addition of more methyl formate so that the amount of methyl formate is four times that of the 2-methylpentane present.

Abstract: Propylene oxide is separated from the crude reaction product resulting from the oxidation of propylene, which separation is effected by distilling said reaction product in the presence of a neutral ester of phosphoric acid.

Abstract: Process for the manufacture of succinic anhydride by eliminating water from succinic acid using a chemically inert hydrophilic solvent which does not form an azeotropic mixture with water, and fractional distillation.

Abstract: Process for preparing technically pure acetic acid from water - acetic acid mixtures by extractive distillation with N-methyl acetamide.