Abstract: A reaction with distillation structure utilizes a plurality of distillation trays and interconnecting catalyst containers which provide a catalytic reaction zone and a primary flow path for descending liquid streams. Catalytic reaction of the liquid streams within the catalyst reaction zone formed in the containers occurs concurrently with fractionation of the reaction products on the distillation trays. The containers preferably extend continuously through the reaction zone of the distillation reactor to allow for dump loading and removal of the solid particulate catalyst. Structure may also be provided within the containers to influence system hydraulics through the accumulation of liquid within the catalyst bed. This is done by providing an open area interiorly of the catalyst bed into which liquid on the distillation and fractionation tray is radially driven.

Abstract: A catalytic distillation system is provided having a first component which is a particulate catalyst useful for carrying out the desired chemical reaction and a second component which is a hollow geometric shape having openings through the outer surface to allow gas and liquid to pass therethrough. The two components are mixed to provide the desired open space and loaded into a distillation column reactor. The hollow geometric shapes provides the spacing, while the openings permit the gas and liquid to flow through, thus providing the requisite vapor liquid contact space and surfaces.

Abstract: A process of treating a ketoxime or aldoxime-containing amide mixture resulting from a Beckmann rearrangement of the corresponding ketoxime or aldoxime. The process involves hydrolysis of the mixture to remove the remaining ketoxime or aldoxime which are converted to the corresponding ketone or aldehyde and then separated off from the mixture. Any amino acid resulting from the hydrolysis can be reconverted to the corresponding amide by raising the temperature of the mixture.

Abstract: A method and apparatus for conducting a catalytic distillation process is provided which allows for maintaining a liquid level in selected portions of the catalyst bed. Three particular processes disclosed are the production of methyl tertiary butyl ether, tertiary butyl alcohol and cumene.

Abstract: A distillation process for the preparation of purified concentrated BDO.High boiling impurities, including color formers, precursors of color formers and tar formers are removed from the BDO early in the process and under mild conditions.

Abstract: Mixtures of isomers, e.g., mixtures of phenethyl bromide and 1-phenyl-1-bromoethane, are separated by (a) selectively condensing one such isomer with an aromatic compound bearing at least one aryl (nuclear) hydrogen atom, e.g., xylene, in the presence of a catalytically effective amount of a Friedel-Crafts catalyst, e.g., ferric chloride, and then (b) separating the product of condensation, e.g., phenylxylylethane, from the unreacted isomer.

Abstract: A process for separating cyclohexanol and other impurities from a mixture containing cyclohexanone and cyclohexanol is disclosed.

Abstract: Purification of 6-aminocapronitrile by heating a mixture containing same and THA and converting the THA to higher boiling compounds, and then distilling the 6-aminocapronitrile. The time required to convert the THA is reduced if an organic carbonyl compound is present in the mixture during heating.

Abstract: Purification of 6-aminocapronitrile by reduction of tetrahydroazepine with a hydride, and then distilling the 6-aminocapronitrile at a pot temperature of less than about 200.degree. C.

Abstract: A method of preparing a column for a reaction with distillation process utilizing a solid particulate catalyst includes the steps of providing a plurality of vertically spaced apart distillation devices, coupling these devices with a plurality of vertically extending horizontally spaced catalyst enclosing containers, extending at least some of the containers through at least two successive distillation devices, then loading a particulate catalyst into the containers to form a catalyst bed whereby distillation and catalytic reaction may occur simultaneously in the column. The method also encompasses a process for concurrent catalytic reaction with distillation which includes the foregoing steps as well as the steps of feeding a liquid stream to the column reactor and onto the distillation devices while a vapor stream moves vertically up through the distillation devices while products of reaction and distillation are withdrawn from the reactor.

Abstract: Butter oil is heated under high vacuum and sparged for up to about 6 hours to remove cholesterol. Walls surrounding a vapor space above the sparged mass preferably are heated to remove cholesterol with reduced loss of desirable low molecular weight components. Alternatively, the temperature of the butter oil is lowered, and the butter oil is sparged with steam for an additional period of up to about 3 hours to partially hydrolyze triglycerides to mono- and di-glycerides and free fatty acids. The low cholesterol butter oil then is cooled before being exposed to air, thus avoiding oxidation which produces off-flavors. The resulting low-cholesterol butter fat and products made therefrom have composition and organoleptic characteristics substantially similar to those of natural butter oil and butter.

Abstract: A process for obtaining a substantially dry alcohol from a mixture comprising alcohol and water in a non-azeotropic amount by utilizing at least a portion of the alcohol in the mixture as the stripping medium.

Abstract: A concurrent catalytic reaction with distillation structure involves a plurality of vapor permeable plates which are arranged in spaced apart relationship with a catalyst placed in the open space between two adjacent plates. The catalyst filled area presents a reaction zone where catalytic reaction can take place and the vapor permeable plates present a large surface area for vapor and liquid phase exchange. The invention also encompasses a process for concurrent catalytic reaction with distillation employing structure as aforedescribed and including the steps of feeding a liquid stream to a column employing such structure and directing the stream through the catalytic reaction zone while concurrently distilling a portion of the liquid to present a vapor stream which is directed in countercurrent relationship to the liquid stream flow.

Abstract: The invention concerns a process and apparatus for manufacturing methyl tert-butyl ether (MTBE) by reacting methanol with an isobutene-containing hydrocarbon mixture.This process is characterized by the steps of:introducing the reactants into a reaction-distillation zone containing at least two superposed and non-contiguous fixed beds (2a, 2b) of catalyst of the sulfonated resin type, wherein passageways are provided for a vapor phase, at least one distillation tray (4a), at least one liquid redistribution tray (5),maintaining distillation conditions in the zone so as to have a descending liquid phase and an ascending vapor phase,maintaining a continuous liquid phase in the lower part of the beds,discharging a vapor phase containing a high proportion of unconverted hydrocarbons from the top (8) of the zone, andwithdrawing a liquid phase of high MTBE content from the bottom (10) of the zone.

Abstract: Diamondoid compounds are concentrated in a solvent mixture containing at least 20% by weight of normal and slightly branched C.sub.5 -C.sub.30 paraffins by selectively converting the paraffins to lower boiling aliphatic hydrocarbons and separating the lower boiling aliphatics from the solvent mixture to yield a concentrated solvent mixture enriched in diamondoid compounds. Useful shape selective catalysts include zeolites having Constraint Indices from about 1 to about 12, such as ZSM-5 and MCM-22.

Abstract: The invention relates to a process and apparatus for manufacturing methyl tert-butyl ether (MTBE) by reacting methanol with isobutene-containing hydrocarbons in a reaction zone having alternate beds of sulfonated resin catalyst and catalyst-free distillation zones wherein the zones also contain liquid redistribution plates.

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: 2,3-Difluoro-5-(trifluoromethyl)pyridine is prepared by contacting a 2,3-dihalo-5-(trifluoromethyl) pyridine with an effective amount of KF or CsF in a polar aprotic solvent (diluent) at an elevated temperature under substantially anhydrous conditions with removal of the difluoropyridine products essentially as they are formed. The starting material may optionally be added as the reaction proceeds to minimize decomposition. The reaction is also optionally conducted in the presence of an acid scavenger and/or a crown ether or other phase-transfer catalyst.

Abstract: A process for preventing the substantial decomposition of an alkyl sulfide compound at high temperatures comprising combining a non-reactive basic compound with the alkyl sulfide compound prior to subjecting the resultant mixture to the high temperatures.

Abstract: Provided by this invention is a process for producing a purified hydrazine hydrate having a low total organic carbon concentration and which involves:a first step which includes distilling an aqueous solution of hydrazine hydrate in the presence of at least one salt selected from the group consisting of chloride, sulfate, phosphate and carbonate of (a) the metals of Group Ia and IIa of the Periodic Table of the Elements, (b) ammonium or (c) hydrazinium to concentrate the aqueous solution of hydrazine hydrate by distilling water and the majority of the total organic carbon constituents off and separating the resultant concentrate as a bottom product, anda second step which includes distilling the resultant concentrate to recover a purified aqueous solution of hydrazine hydrate as a top product and separating an aqueous solution of the above salt as a bottom product.

Abstract: A method of distillation employing a heat pump (which may be driven by a compressor) using a vapor stream from within the distillation system as a heat source and a liquid stream from within the distillation system as a heat sink. The selection of heat-source vapors and heat-sink liquid is such that at least one is withdrawn from the phase-contacting region of the distillation system. The return of streams withdrawn from the phase-contacting region of the distillation system to the distillation system is such that at least one of the streams is returned at a temperature different from that of the point from which it was withdrawn, and all withdrawn streams are returned in manner such that a stream removed as vapor is returned at a point with a temperature at most that at the point it was withdrawn, and a stream removed as liquid is returned at a point with a temperature at least that at which it was withdrawn.

Abstract: Carboxylic esters obtained by reacting olefinically unsaturated compounds with carbon monoxide and alcohols and containing aldehydes, acetals and/or unsaturated compounds are purified by(a) treating the carboxylic ester which contains an aldehyde, acetal or unsaturated compound in a first stage at from 20.degree. to 200.degree. C. with a strongly acidic agent and(b) hydrogenating the mixture thus treated in a second stage at from 50.degree. to 200.degree. C. under a pressure of from 1 to 50 bar in the presence of one or more metals of subgroup VIII of the periodic table and(c) removing low and high boilers from the hydrogenated mixture obtained in stage b by distillation and obtaining a pure carboxylic ester.

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: This is a process for removing phosphorus oxychloride from a complex of zirconium or hafnium chloride and phosphorus oxychloride utilizing a lithium-potassium chloride molten salt absorber vessel displacing phosphorous oxychloride from the complex, with a condenser which has the complex of zirconium or hafnium chloride and phosphorus oxychloride as the condensing fluid to scrub zirconium or hafnium chloride from the phosphorus oxychloride vapor released from the complex. The process uses at least one separate vessel to strip the zirconium or hafnium chloride from the lithium-potassium chloride molten salt.

Abstract: This is a zirconium-hafnium separation process utilizing a complex of zirconium-hafnium chlorides and phosphorus oxychloride. The complex is introduced into a distillation column and a hafnium chloride enriched stream is taken from the top of the column and a zirconium chloride enriched stream is taken from the bottom of the column. In particular, the invention utilizes prepurification of the zirconium-hafnium chlorides prior to introduction of the complex into the distillation column to substantially eliminate iron chloride; thus, the buildup of iron chloride in the distillation column is substantially eliminated and the column can be operated in a continuous stable, and efficient manner.

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: This is an improved method for separating hafnium from zirconium of the type where a complex of zirconium and hafnium chlorides and phosphorus oxychloride is prepared from zirconium-hafnium chloride and the complex is introduced into a distillation column, with the improvement comprising: electrochemical breaking of the zirconium of hafnium chloride complex taken from said distillation column to separate product from the complex. The electrochemical breaking of the complex, possibly by reducing zirconium or hafnium, is done in a molten salt bath. Preferably, the molten salt in said molten salt bath consists principally of a mixture of alkali metal and alkaline earth metal chlorides and zirconium or hafnium chloride. The product can be either chloride, metal, or mixed metal and subchloride for further processing.

Abstract: A process for improving the quality of phenol which comprises(a) introducing a liquid phenol composition comprising above about 95 weight percent phenol on a dry basis, organic acid contaminants, and organic ketone contaminants;(b) introducing water into the distillation tower, together with the phenol stream or in a separate stream;(c) heating the phenol composition and water to a temperature sufficiently high to vaporize the water;(d) allowing the organic acid contaminant to build to a concentration whereby sufficient acid is present to catalyze a reaction between an organic ketone contaminant and phenol, thereby forming a new compound(s) and;(e) removing the said formed compound(s) from the distillation tower by hydroextractive steam distillation.

Abstract: Excess amounts of a pure form of acrylonitrile are reacted with other reactants in the production of various compounds such as 2-acrylamido-2-methyl propane sulfonic acid. Accordingly, large amounts of acrylonitrile remain unreacted and present with other contaminants. The present invention is directed toward the purification of such unreacted acrylonitrile and the purified acrylonitrile obtained from such a purification process. The purification is carried out by treating the unreacted acrylonitrile with a base and removing salts formed. The treated material is fed to a heat exchanger which heats the material preferably under vacuum to about 120.degree. F. and provides a heated fluid material. This heated fluid material is pumped to a lower area of a distillation tower which is maintained under vacuum and includes a plurality of distillation trays.

Abstract: Isomer mixtures of 1,3- and 1,4-bis-(2-hydroxyhexafluoroprop-2-yl)-benzene are separated by a steam distillation in the presence of CS.sub.2. On cooling of the steam distillate, a solid precipitates which is composed mainly of the 1,4-isomer. After the solid has been separated off, an aqueous-organic liquid-phase mixture remains, the organic phase of which mainly contains the 1,3-isomer. The pure isomers are obtained by recrystallization or distillation respectively. These are mainly intermediates in the polymer field.

Abstract: An improved process for purifying thionyl chloride by the double distillation of an impure mixture of thionyl chloride, sulfuryl chloride, sulfur monochloride, sulfur dichloride and sulfur dioxide is disclosed. The double distillation process is conducted in the presence of sulfur to convert sulfur dichloride into sulfur monochloride. The sulfuryl chloride content of the mixture is reduced by contacting the vapor from the reboiler in the first stage distillation with activated carbon prior to fractional distillation in the column. The product of the first stage distillation is then redistilled to produce a thionyl chloride product of high purity.

Abstract: A process for the purification of 1,2-dichloroethane is described, in which the crude product, containing not more than 3% by weight of high-boilers, is distilled in a first column at 125.degree. to 180.degree. C. in such a way that the bottom product contains not more than 7% by weight of high-boilers. The purified, vaporous 1,2-dichloroethane discharged at the head of this column is used to heat product streams containing 1,2-dichloroethane. The bottom product from the first column is distilled in a second column, advantageously at a pressure of 5 to 40 kPa, together with a feed composed of vaporous 1,2-dichloroethane obtained from the reaction of ethylene with chlorine. The process makes it possible to purify 1,2-dichloroethane with a saving in energy.

Abstract: A method of removing color from crude triethylenetetramine (TETA) is disclosed. In the preferred procedure, acid treated clay or acidic form zeolite are mixed with the TETA at elevated temperatures. After several hours exposure, the TETA is distilled to obtain a decolored product. The decoloration can be a continuous or batch process. The distillation is performed in the presence or absence of the catalyst.

Abstract: A process of decoloring crude triethylenetetramine (TETA) is disclosed. In the disclosed and preferred procedure, a sulfonic acid ion exchange resin acts on the crude TETA to enable subsequent distillation at elevated temperature to obtain decolored TETA.

Abstract: A process for removing by product acetone from reaction mixtures obtained by reacting methyl acetate and/or dimethylether with carbon monoxide at elevated temperatures to obtain acetic anhydride in the presence of a catalyst system consisting essentially of carbonyl complexes of noble metals belonging to group VIII of the Periodic System of the elements, acetic acid, an organophosphorus or organonitrogen compound, and methyl iodide whereby the acetone obtained as a by-product during the reaction is subjected to condensation at temperatures of 50.degree. to 250.degree. C., under pressures of 0.01 to 150 bars and at a molar ratio as above defined for the catalyst system constituent of 1:(25-500):(10-100):(15-150) so as to obtain predominantly higher-boiling secondary products to be distillatively separated in a successive distillation zone together with volatile constituents of the catalyst system.

Abstract: Olefin mixtures containing vinyl, vinylidene and internal olefins are upgraded in value by removing the vinylidene olefin content and lowering the internal olefin content by selective reaction with a sulfur halide such as S.sub.2 Cl.sub.2 followed by reaction with aqueous alkali metal hydrosulfide and optionally alkali metal sulfide. The reaction mixture is distilled to remove mainly vinyl and a reduced amount of internal olefins. The distillation residue is an effective extreme pressure additive for lubricating oil.

Abstract: A process for purifying hydrogen fluroide characterized by adding fluorine to hydrogen fluoride containing at least one element selected from the group consisting of boron, silicon, phosphorus, sulfur, chlorine and arsenic, and/or at least one compound of these elements, reacting the fluorine with said element and/or said compound and distilling the resulting mixture.

Abstract: The disclosure relates to a process for separating iodine and its compounds from the carbonlyation products acetic acid, acetic anhydride or ethylidene diacetate obtained by subjecting dimethylether, methyl acetate or methanol to a carbonylation reaction. For reducing the quantity of total iodine contaminating the carbonlyation products to less than 20 ppb iodine, the disclosure provides for the carbonylation products to be treated at temperatures of 20.degree. to 250.degree. C. with an alkyl or aryl phosphine or a heterocyclic aromatic nitrogen compound and at least one of the metals copper, silver, zinc or cadmium or their compounds and to be distillatively separated from the iodine thereby fixed in non-volatile form.

Abstract: Isoprene is recovered from a C.sub.5 -hydrocarbon mixture containing isoprene, penta-1,3-diene and cyclopentadiene by separating the said mixture by liquid-liquid extraction or extractive distillation with the aid of a selective solvent, in combination with a distillation upstream or downstream from the liquid-liquid extraction or extractive distillation, by a method in which a stream containing penta-1,3-diene and cyclopentadiene is separated off in the upstream or downstream distillation and is catalytically hydrogenated, and the hydrogenated stream is fed to the upper part of the liquid-liquid extraction or extractive distillation.

Abstract: A novel catalyst system for use in a distillation column reactor is disclosed including annularly-defined spaces within the reactor comprised of vapor-permeable material with packed catalyst and alternately positioned vapor barrier means.

Abstract: This invention relates to the use of a salt and/or a mild caustic in solution to increase the relative volatility of aromatics contained in an aqueous stream. The increased relative volatility so achieved enables more efficient concentration of the aromas via distillation. The pH of the aroma-containing aqueous stream does not exceed 7.0 through the addition of the salt or caustic to prevent aroma degradation.

Abstract: A C.sub.4 -hydrocarbon mixture which essentially contains n-butenes and butanes is separated by a process in whichthe mixture is reacted with a carboxylic acid in the presence of an acidic catalyst to form a butyl carboxylate,the reaction mixture obtained from the esterification zone is distilled to give, as the top product, a fraction containing the butanes, and, as the bottom product, a fraction containing the resulting butyl carboxylate,the butyl carboxylate is decomposed at elevated temperatures to give the carboxylic acid and n-butenes, andthe mixture of n-butenes and carboxylic acid is then distilled, the n-butenes being obtained as the top product, and the carboxylic acid as the bottom product.

Abstract: A process for separating a butene-1/isobutene mixture from a C.sub.4 hydrocarbon fraction is provided which comprises subjecting the C.sub.4 hydrocarbon fraction to extractive distillation using a polar solvent to separate components predominantly containing 1,3-butadiene as an extract and obtain an overhead containing butanes, butene-1, isobutene and butene-2 as main components and being substantially free from C.sub.3 -C.sub.4 diolefinic and acetylenic hydrocarbons, feeding the overhead into a first distillation column, removing isobutane as an overhead component from the first distillation column, feeding high-boiling components from the bottom of the first distillation column to a second distillation column, removing n-butane and butene-2 from the bottom of the second distillation column, and obtaining highly pure butene-1 and isobutene from its top.

Abstract: A process for separating a butene-1/isobutene mixture from a C.sub.4 hydrocarbon fraction is provided which comprises subjecting the C.sub.4 hydrocarbon fraction to extractive distillation using a polar solvent to separate components predominantly containing 1,3-butadiene as an extract bottom and obtain an overhead containing butanes, butene-1, isobutene and butene-2 as main components and being substantially free from C.sub.3 -C.sub.4 diolefinic and acetylenic hydrocarbons, feeding the overhead into a first distillation column, removing n-butane and butene-2 as bottoms from the column, feeding low-boiling components from the top of the column into a second distillation column, removing isobutane from the top of the second distillation column, and obtaining highly pure butene-1 and isobutene from its bottom.

Abstract: A method for improving ruthenium decontamination efficiency in a nitric acid recovery system in which a nitric acid solution containing ruthenium is subjected to an evaporation treatment in a nitric acid evaporator. The method is characterized by carrying out the evaporation treatment of the nitric acid solution in the presence of hydrazine in a concentration of 20 to 5000 mg per liter of the solution in the evaporator. By the action of hydrazine, the evaporation of ruthenium contained in the solution is suppressed during the evaporation treatment, and hence the ruthenium decontamination efficiency is remarkably improved.

Abstract: Ethylene glycol is purified, particularly for fiber-grade applications, by removal of the residual ethylene carbonate from which the glycol was derived. The effluent from a reactor in which ethylene carbonate is hydrolyzed to ethylene glycol is distilled to produce a lower-boiling fraction comprising substantially ethylene glycol and water and a higher-boiling fraction comprising substantially ethylene glycol, higher glycols, and concentrated in hydrolysis catalyst. The higher-boiling fraction is recirculated to reflux against the lower-boiling product, thereby essentially completing the hydrolysis of unreacted ethylene carbonate thereby reducing the ethylene carbonate content of the ethylene glycol to very low levels suitable for fiber-grade applications.

Abstract: The subject invention relates to the preparation of storage-stable alkylene glycol monoalkyl ethers having the general formulaR--(O--A--).sub.n OHin which A represents an ethylene or propylene group, R denotes a C.sub.1 -C.sub.4 -alkyl group, and n has a value of 1 to 4. They are prepared by carrying out the fractional distillation of a mixture which is produced by the alkali catalyzed reaction of ethylene oxide or propylene oxide with an alcohol in the presence of 0.1 to 20 ppm of ammonia based on the amount of the mixture.

Abstract: A method for isomerizing isobutene or n-butene to produce a mixture of isobutene and normal butene, and polymerizing at least a portion thereof to produce isobutene/n-butene codimer, which comprieses feeding at least 80 weight % of either the isobutene or n-butene to a catalytic distillation reactor containing a fixed bed acidic cation exchange resin catalyst packing which provides both the catalyst sites and distillation sites for the reaction products, isomerizing a portion of the isobutene or n-butene to produce a mixture of isobutene and n-butene and reacting at least a portion of the isobutene and n-butene to form codimer of isobutene and n-butene, whereby an overhead fraction containing any unreacted isobutene and n-butene and a bottoms fraction containing codimer is produced. The result of the reaction is substantially the same regardless whether the feed is isobutene or n-butene. Other aspects of the invention, include combinations of procedures to produce high purity isobutene and n-butene.

Abstract: 3,4-Diacetoxybutene-1 can be easily isomerized into 1,4-diacetoxybutene-2 by contacting it with a cation exchange resin. This method is capable of providing an excellent reaction result and is free of the problem of corrosion of apparatus as well as the problem of formation of by-products. When acetic acid is present in said isomerization operation, the reaction rate is increased. Further, combination of this isomerization method with separation of 1,4-diacetoxybutene-2 from 3,4-diacetoxybutene-1 by distillation enables production of high-purity 1,4-diacetoxybutene-2 at a high efficiency.