Abstract: A feedstock containing alpha olefins and internal olefins is converted into a first product having an enhanced internal olefin content over that of the feedstock and into a second product having an enhanced alpha olefin content over that of the feedstock by:(a) contacting the feedstock with an anthracene at a temperature ranging from 150.degree. to 275.degree. C. to form an olefin adduct with anthracene,(b) separating the adduct from the product of step (a) to leave a first product enriched in internal olefin,(c) heating the separated adduct at a temperature of from 250.degree.-400.degree. C. to produce anthracene and an olefin product enriched in alpha olefin, and(d) separating anthracene from the product of step (c) to produce a second product enriched in alpha olefin. Linear olefins are preferred feedstocks.

Abstract: A process for the purification of 1,1-diphenylethane with good fragrance quality. The product is produced by first subjecting the distillation residue from ethylbenzene production to distillation, then treating the distillate with sulfuric acid, separating the sulfuric acid phase, washing the oil phase with an alkali metal hydroxide solution and water, and subjecting the oil phase thus obtained to a second distillation.

Abstract: A process for the removal of water from a lower alkanesulfonic acid-water mixture by causing the mixture to run down the internal walls of two vertical evaporator columns operated in series, is disclosed herein.

Abstract: A two-step distillation process provides semiconductor purity, concentrated hydrofluoric acid. Further, the distillation process, occurring under reduced pressures eliminates essentially pure water after the first distillation step. The product output of the second distillation process provides an acid of weight percent greater than 27 weight percent. The product acid is carefully diluted to the required concentrations during the dilution step.

Abstract: Water-insoluble crystallizable epoxy alcohols such as phenyl glycidol are recovered from epoxidation reaction mixtures by washing the mixture with water, concentrating the mixture by distillation under vacuum to remove unreacted hydroperoxide and alcohol co-product, and crystallizing the epoxy alcohol from solution. Minimal decomposition of the epoxy alcohol is observed.

Abstract: Dodecene-1 and 1-tetradecene can be rectified from a mixture containing 1-dodecene and 1-tetradecene and triethylaluminum ("TEA") which has about the same normal boiling point as 1-dodecene and 1-tetradecene by feeding the above mixture to an intermediate point of a rectification column maintained under sufficient vacuum (e.g. 5-30 torr) such that the temperature at the intermediate feed point is about 250.degree.-260.degree. F. and the overhead distillation temperature is about 190.degree.-240.degree. F. The TEA which normally boils at about the same temperature as 1-dodecene and 1-tetradecene will exist as a dimer permitting part of the 1-dodecene and 1-tetradecene to distill overhead and most of the TEA to exit the bottom of the column.

Abstract: Tetrahydrofuran is recovered by a two stage distillation procedure from a crude hydrogenation product resulting from vapor phase hydrogenation of diethyl maleate and containing water, ethanol and a minor amount of n-butanol, and possibly also dissolved hydrogen, in addition to butane-1,4-diol, gamma-butyrolactone and "heavies" such as diethyl ethoxysuccinate. In the first distillation stage, conveniently operated substantially at atmospheric pressure, ethanol, water, and tetrahydrofuran are recovered as overhead product, are condensed to separate the condensible components from a hydrogen stream which can be vented, and then redistilled in the presence of a molar excess of a hydroxylic solvent containing at least two hydroxyl groups, such as butane-1,4-diol, in a second distillation zone.

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: Process for the separation of HF, 2,2-dichloro-1,1,1-trifluoroethane (FC-123) and/or 2-chloro-1,1,1,2-tetrafluoroethane (FC-124) mixture by subjecting the mixture to a temperature from about -80.degree. C. to about 40.degree. C. and a pressure from about 0.10 MPa to about 3.55 MPa in a separation zone, whereby an organic phase having less than 15 mole percent of HF is formed as the bottom layer in the separation zone and an acid phase having at least 93 mole percent of HF is formed at the top in the separation zone.

Abstract: An apparatus and process for separating a more volatile substance from a liquid in which it is dissolved by vacuum means. The apparatus has a perforated inner casing having a plurality of sub-stages which contain packing material to provide a tortuous path of interstices for the liquid to flow through; an outer casing surrounds the inner casing to define an evacuating space between the outer and inner casing and vacuum means to create a vacuum in the evacuating space which communicates with the sub-stages through the perforations in the inner casing. The vacuum means also acts to pull off the more volatile substance.

Abstract: By extracting hydrogen fluoride from 2,2,3,3-tetrafluorooxetane with a halogenated hydrocarbon, a mixture of 2,2,3,2-tetrafluorooxetane and the halogenated hydrocarbon containing a small amount of hydrogen fluoride is obtained. The mixture may be distilled at least twice to obtain a mixture of 2,2,3,2-tetrafluorooxetane and the halogenated hydrocarbon containing substantially no hydrogen fluoride.

Abstract: There is disclosed an improved process for the manufacture of glyoxylic acid obtained by oxidation of glycolic acid. For processing purposes alkyl esters of these acids are employed. Increased efficiency is obtained by recovering glycolate rich streams from one or more distillation operations and after treatment to remove acetic acid by-product the streams are recycled to the oxidation reaction.

Abstract: 1,3-Butadiene is isolated from a C.sub.4 -hydrocarbon mixture containing 1,3-butadiene and small amount of propyne and C.sub.5 -hydrocarbons by extractive distillation with a selective solvent and subsequent distillative purification of the crude 1,3-butadiene obtained in the extractive distillation.

Abstract: A fractional distillation system is provided for fractionating unequal liquid mixtures with lower heat throughput and lower energy consumption. For mixtures in which the heavy fraction is predominant (FIG. 1), a stripper (2) pre-fractionates part of the mixture at lower pressure and at no extra energy cost by being reboiled by an intermediate condenser (3). The pre-fractionator temperature range is preferably nested within (overlapped by) the distillation column (6) temperature range.

Abstract: The invention relates to a process for the isolation of vinyl acetate from a gas mixture containing vinyl acetate, ethyl acetate, water and carbon dioxide formed in the reaction of ethylene with acetic acid and oxygen in the gas phase over catalysts containing palladium or palladium compounds. The gas mixture leaving the reaction zone is passed into a distillation column and the gas mixture leaving the top thereof is cooled. The gas which is not condensed during the cooling is washed with acetic acid in a washing column, an acetic acid solution containing vinyl acetate being obtained. The bottom product from the distillation column is passed to a second distillation column and a side stream containing ethyl acetate is removed from an enrichment zone above the bottom thereof, all or some of the bottom product from the second distillation column, which product chiefly consists of acetic acid, being used for the wash in the washing column. The top vapor of the second distillation column is cooled.

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: The instant invention relates to a process for the purification of dimethylether, which contains impurities, by feeding a mixture which contains the dimethylether at specific trays to a distillation column and withdrawal of the dimethylether and of impurities at specific trays of the same column.

Abstract: Ammonia which is present in fuel cell power plant water in free form, in ionic form, and in forms combined with carbon dioxide, is removed from the power plant water by steam stripping. Water which has been used to cool the fuel reformer effluent, and thus has become contaminated with ammonia, is fed to a first steam stripper wherein a first portion of the ammonia contaminant is removed. The partially stripped water is then fed to a second steam stripper wherein further amounts of ammonia are removed from the water with steam. The ammonia laden steam from the two strippers is combined and vented through a single vent thus conserving the amount of water lost from the system.

Abstract: In the purification of ethylene oxide from an ethylene oxide-containing reaction formation gas produced by catalytic gas-phase oxidation of ethylene with a molecular oxygen containing gas, external thermal energy required for heating an ethylene oxide refiner is economized by a method which utilizes the diffusate obtained from the top of an ethylene oxide stripper as a heat source for the refiner. Further, the bottom liquid of the stripper can be used as a heat source for ethylene oxide refiner and/or a light ends stripper.

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: A process is disclosed for separation of propionic acid and methacrylic acid and esterification of methacrylic acid with an aliphatic alcohol of from 1 to 4 carbon atoms in presence of a suitable catalyst wherein separation and esterification is obtained with minimal polymerization of methacrylic acid.

Abstract: An aqueous effluent is supplied to a stripping column (total stripping column) from which a mixture that is rich in NH.sub.3, CO.sub.2 and H.sub.2 S is withdrawn as a head product. In at least one additional stripping column the mixture is separated into a mixture which is rich in NH.sub.3 and a mixture which is rich in the sour gaes CO.sub.2 and H.sub.2 S. The mixture which is rich in NH.sub.3 is scrubbed with liquid ammonia. The overhead product from the total stripping column is cooled in a condenser under a pressure of 1 to 7 bars and is thus transformed into a liquid phase to such an extent that the liquid phase contains 70 to 100% of the NH.sub.3 which has been supplied to the condenser. The liquid phase is supplied at a temperature of 30.degree. to 90.degree. C. to a second stripping column (NH.sub.3 stripping column), which is operated under a pressure of 1 to 4 bars and from which a gas mixture that is rich in NH.sub.3 is withdrawn as a head product.

Abstract: High purity butene-1, in particular polymerization grade butene-1, is obtained by means of a two-stage fractionation of a C.sub.4 hydrocarbon stream comprising butene-1 which is substantially free from butadiene.The first stage of the fractionation process allows practically all the isobutane contained in the C.sub.4 batch to be separated as the top stream.The bottom phase of the first stage of fractionation is supplied to the second stage of fractionation thus obtaining high purity butene-1 as the top fraction, and the remaining components as the bottom phaseAccording to the process of the invention, vapors of butene-1 obtained as the top stream from the second stage of fractionation are compressed and the resultant heat of condensation is used for operating the reboilers of the two fractionation stages.

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: The invention concerns a process for the degassing, dehydrating and lower boiling component separation during straight-run distillation of crude fatty acids. The crude fatty acids are degassed in the degassing stage at such temperatures and pressures in counter current flow with stripping steam that no appreciable dehydration or lower boiling component separation takes place at this stage, then the degassed crude fatty acid is then led to a precut column for dehydration and lower boiling component separation, whereby the falling film concentrator column operates as a partial condensation stage for the creation of the reflux of the fatty acids, which is necessary for the lower boiling component separation, and that the easily boiling component evaporates almost completely in the precut column and is led off from the precut column in vapor form, together with the water.

Abstract: An improved process for purification of glycerol obtained from natural sources comprising alkalizing a glycerol-containing crude mixture in the presence of air for oxidation, evaporating the mixture in a thin-layer evaporator with redistillation of the residue, rectification and reevaporation in a packed column characterized by low-pressure-loss plates with a falling-film evaporator designed for internal and external partial condensation and to separate off unwanted constituents of the mixture, bleaching the product with activated carbon and separating the bleach in known manner.

Abstract: Crude cumene hydroperoxide is purified by subjecting it to an evaporation step at a pressure of about 2 to 10 (preferably 3 to 7) mg Hg abs. and a temperature of about 150.degree. F. to about 210.degree. F. (pref. about 175.degree. F. to 195.degree. F.) to remove light impurities and then subjecting the residue from the first evaporation step to a second evaporation step also at a temperature of about 135.degree. F. to 210.degree. F. (pref. about 150.degree. F. to 185.degree. F.) but at a pressure of about 0.5 to about 8 (preferably 1 to 3) mm Hg abs. to obtain a distillate significantly reduced in color bodies, water, acetophenone, and dimethylbenzyl alcohol, and sodium.

Abstract: For the distillation of a stream consisting essentially of alcohols of 6-20 carbon atoms, water and methanol, the methanol is first separated from the homogeneous, aqueous solution as the overhead product by distillation under a head pressure of 500-1,000 mbar. The bottoms discharge is mechanically separated under normal pressure and at a temperature of 5.degree.-95.degree. C. in a phase separator to obtain a discrete water phase preferably containing at least two thirds of the feedstream water. The remaining organic phase is then transferred from the phase separator into a second distillation column and the organic phase is dewatered in the latter at 100-500 mbar. The head product from the second column is conducted to a second phase separator; the aqueous phase is separated therein at a temperature of 5.degree.-95.degree. C. and optionally returned into the first phase separator. The bottom product from the second distillation column is passed into a downstream distillation stage wherein the C.sub.6 to C.

Abstract: A process for the separation of ethylene glycol from glycolated water obtained from the bottom of an ethylene oxide desorption column in a process for the manufacture of ethylene oxide by catalytic oxidation of ethylene by oxygen in the vapor phase, comprising feeding said glycolated water directly from the bottom of said ethylene oxide desorption column into the top of a separation column having therebelow up to 12 theoretical plates and adding sufficient indirect heat to said glycolated water to form two streams; a first gaseous stream consisting essentially of steam which is removed from the top of said separation column and introduced into said ethylene oxide desorption column to serve therein as the desorption fluid, and a second aqueous stream containing from about 40% to 90% by weight of ethylene glycol which is removed from the bottom of said separation column.

Abstract: A method and apparatus for distilling, especially vacuum refining and deodorizing edible oils and fats utilizing sheets of oil driven downwardly in a distiller with a vacuum source at its top. A nozzle includes pressure equalization chambers, cantilever adjustment screws, and a central drag sheet to produce longer lasting and more uniform thin oil sheets to be driven in the distiller. A continuous process deaerates, dehydrates, degums, bleaches, refines, removes tocopherol, deodorizes, and strips peroxides and hydroperoxides from raw oil in a series of isothermal stages utilizing driven sheet distillers. No stripping steam is used except in the stage which strips peroxides and hydroperoxides. The method produces valuable, pure products such as tocopherol and fractionated fatty acids. It is especially efficient in heat exchange and low in waste and pollution producing products.

Abstract: Methacrylonitrile higher in purity than that obtained by the conventional process is efficiently produced by the present improved process for producing purified methacrylonitrile in which the reaction mixture formed by the ammoxidation of isobutylene or tert-butyl alcohol is distilled using water as solvent to obtain a crude methacrylonitrile solution which contains methacrylonitrile as major constituent, methacrolein, hydrogen cyanide, and isobutyronitrile, and the crude methacrylonitrile solution is then purified in a product column, wherein the improvement comprises first removing isobutyronitrile from said crude solution, then feeding the remaining solution to the product column, withdrawing from the top a vapor containing methacrolein, condensing the vapor, returning a greater part of the condensate to the product column while removing the remainder from the distillation system, and withdrawing purified methacrylonitrile from the middle or lower section, preferably from a point lower than the feeding sta

Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from wastewaters such as coke-plant or coal conversion wastewaters. The process involves adding alkali to these wastewaters in amounts sufficient to react with fixed ammonia salts present in the wastewater and to enable substantial amounts of the ammonia to be evolved upon distillation, and subjecting the thus treated wastewater to distillation to remove substantial amounts of the ammonia and acid gases present from the wastewater. This process is achieved by two separate and successive distillations. In this process, the vapor streams being withdrawn from the first and/or second distillations are subjected to an impurity removal process to thereby produce a vapor stream substantially reduced in impurities, and useful as a stripping vapor in this process, and then reusing this vapor stream as a stripping vapor in the process.

Abstract: Distillation of the heavy waste stream from the manufacture of phenol via the cumene process provides an overhead stream containing phenol, acetophenone and 2-phenyl propionaldehyde. Extraction of the overhead stream with aqueous caustic removes the phenol and subsequent distillation of the remaining two components in the presence of a catalytic amount of caustic provides a substantially pure acetophenone distillate.

Abstract: Production of essentially pure Z-11-hexadecenal by azeotropic distillation is described. Contacting a mixture of Z-11-hexadecenal, hexadecene and hexadecadiene with dimethylsulfoxide and subjecting the blend to azeotropic distillation allows for the removal of hydrocarbon impurities from the aldehyde. Contacting a mixture of Z-11-hexadecenal and hexadecenol with a C.sub.2 -C.sub.4 glycol and subjecting the blend to azeotropic distillation conditions allows for the recovery of a glycol-aldehyde azeotrope from which essentially pure aldehyde is readily recovered. A mixture comprising Z-11-hexadecenal, hexadecene, hexadecadiene and hexadecenol can be sequentially treated according to the above-described azeotropic distillation steps in order to provide essentially pure Z-11-hexadecenal.

Abstract: A process to recover acrylic acid or methacrylic acid by using a split quench process which allows acrylic acid or methacrylic acid to be recovered from the resulting aqueous solutions by a combination of solvent extraction and azeotropic dehydration that minimizes the amount of solvent required.

Abstract: The disclosure relates to a process for separating the catalyst system from reaction mixtures which are obtained by reacting methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen at elevated temperatures to acetic anhydride and optionally ethylidene diacetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals belonging to group VIII of the Periodic System, acetic acid, an organophosphorus or organonitrogen compound, methyl iodide and optionally compounds of carbonyl-yielding common metals, and which issue from the reaction zone under a pressure of 25 to 150 bars at a temperature of 100.degree. to 250.degree. C. More particularly, the reaction mixture coming from the reaction zone is introduced into a separator heated to 60.degree. to 140.degree. C. and released to a pressure of 0.5 to 3.

Abstract: Disclosed is a process for recovering a virtually water-free amine from an amine acid salt thereof. The process comprises a unique combination of phase separation stages practiced under mild heating and distillation stages. An amine product containing less than 0.2% water can be achieved by the present process. The feedstock for the process suitably is an acid scrub liquor used to scrub amine from a vapor stream thereof which has been used in a cold-box molding process in the foundry industry or in the cure of vapor permeation curable coatings in the coatings industry.

Abstract: The process gives highly pure cyclopentadiene and methylcyclopentadiene from a cracked gasoline fraction. The merit of the process is that cyclopentadiene and methylcyclopentadiene are recovered by adding a simple distillation system to a conventional cracked gasoline treating plant without altering the plant and operating conditions thereof. An internal reflux stream is withdrawn from the stripping section of a BTX column of a conventional cracked gasoline treating plant, and is sent to a depolymerization-distillation column operated at a bottom temperature of 160.degree.-230.degree. C. The overhead stream of the column is sent to a cyclopentadiene column operated at a bottom temperature of 160.degree.-230.degree. C. Cyclopentadiene is recovered from the overhead of the column, and the bottom stream is sent to methylcyclopentadiene column operated at a bottom temperature of 170.degree.-210.degree. C. Methylcyclopentadiene is recovered from the overhead of the column.

Abstract: A process for continuous rectification of a liquid mixture containing alcohols, particularly a liquid fermate, employs a plurality of distillation columns to which the liquid mixture is fed in parallel, and which have successively reduced operating pressures and temperatures from an initial one to a final one thereof. The top vapor distillate from the higher-pressure columns supplies driving heat to the sumps of the next successively lower-pressure columns. Direct steam at 130.degree. C. to 160.degree. C. is fed to the sump of the column operated at the highest pressure. Direct steam is generated by indirect heat exchange of water with the top vapor withdrawn from the columns, and the resulting direct steam is fed to the sumps of the next-lower-pressure columns. The apparatus can also include a section for the production of absolute alcohol.

Abstract: Block short-way evaporator with wiped-off film for vacuum and molecular distillation which is suitable for large-scale production. The evaporator is composed of one or more vacuum chambers in which parallel vertical double-sided flat evaporators with wipers for wiping evaporating areas and double-sided flat condensers are alternately located so that they form a continuous block. On the bottom of each chamber distillate collecting troughs with distillate tubes are formed alternately below double-sided flat condensers using separating partitions, and below double-sided flat evaporators residue collecting troughs with residue outlet tubes are formed, feed tubes being led through the bottom and the double-sided flat evaporators into separating troughs in the upper part of the double-sided flat evaporators.

Abstract: High purity alkyl glyoxylate is produced from complex mixtures containing alkyl glyoxylate, alkyl glycolate, water, alcohol and miscellaneous impurities. High purity alkyl glyoxylate is useful in the synthesis of alkyl glyoxylate polymers.

Abstract: An improved process for the batch distillation or purification by stripping of a bis(hydroxyalkyl)disiloxane, which purified product is useful as a video disc lubricant additive or dopant. In accordance with the process, the feedstock of bis(hydroxyalkyl)disiloxane is subjected to a vacuum evaporation of the light volatiles by gradually reducing the pressure to about 2.times.10.sup.-1 Torr. After the low boiling materials have been distilled off, the temperature is gradually increased and the pressure gradually reduced (final temperature of about 135.degree. C. and final pressure of about 4.times.10.sup.-2 Torr) so as to produce a distill and having a viscosity of about 210.+-.30 centipoise at 25.degree. C.

Abstract: A C.sub.1 -C.sub.4 alkanol and its corresponding acetate or a C.sub.1 -C.sub.2 alkanol and its corresponding propionate are separated by extractive distillation utilizing an aromatic hydrocarbon as the extractive solvent. Transesterification of lower alkanols and lower alkyl acetates or propionates is effected by means of extractive distillation and the preparation of an intermediate ester of a higher boiling alcohol.

Abstract: Disclosed is a process for recovering a virtually water-free amine from an amine acid salt thereof. The process comprises a unique combination of phase separation stages practiced under mild heating and distillation stages. An amine product containing less than 0.2% water can be achieved by the present process. The feedstock for the process suitably is an acid scrub liquor used to scrub amine from a vapor stream thereof which has been used in a cold-box molding process in the foundry industry or in the cure of vapor permeation curable coatings in the coatings industry.

Abstract: A liquid containing a contaminant such as water or polymeric solids is purified. Purification of a liquid containing a contaminant is enhanced by the use of second fractionating column in conjunction with a first fractionating column to recover a portion of the liquid to be purified from the kettle product of the first column. Vapor from a second fractionating column is used to control the total energy input to a first fractionating column.

Abstract: An improved distillation method and apparatus are provided for recovering anhydrous ethanol from fermentation or synthetic feedstocks. The system includes at least one stripper-rectifier tower, a dehydrating tower, and an azeotropic agent stripping tower. Substantial energy savings are realized by operating the dehydrating tower, and preferably also the azeotropic agent stripping tower, at a higher pressure than the stripper-rectifier tower and by condensing the overhead vapors from the dehydrating tower (or dehydrating tower and azeotropic agent stripping tower) to provide the heat required in the stripper-rectifier tower. In a preferred embodiment, two stripper-rectifier towers are used, one operating at a higher pressure than the other, in which case the higher pressure tower is heated as just described and the overhead vapors from the higher pressure tower are condensed to supply the heat required in the lower pressure tower.

Abstract: A process for the preparation of pyrocatechol and hydroquinone by reaction of phenol with a peroxidic hydroxylating reagent followed by working-up of the resultant reaction mixture is disclosed. The work-up procedure is carried out in a first rectification column operated under specified conditions and having specified separation stages in a rectification section and a stripping section whereby there is distilled overhead components which boil at a temperature lower than phenol. Taken off from the bottom is a mixture comprising phenol and materials of higher boiling point which are fed into a second rectification column which is also operated under very specified conditions whereby pure phenol is recovered overhead leaving a bottoms comprising phenol pyrocatechol and hydroquinone which are then processed to separate phenol from a mixture of pyrocatechol and hydroquinone.

Abstract: A process for the isolation of hydroquinone, pyrocatechol, phenol and carboxylic acid from the reaction mixture containing the same such as one obtained by reaction of phenol with percarboxylic acid is disclosed. The reaction mixture is fed to a first rectification column and subjected to distillation whereby there is obtained a bottoms product containing pyrocatechol, hydroquinone and phenol. The top product is largely condensed and recycled, there being withdrawn from the top of the rectification column a mixture comprising phenol and carboxylic acid. The phenol and carboxylic acid mixture are continuously fed to a second rectification column where carboxylic acid is separated from phenol and substantially pure phenol is withdrawn from the stripping section and/or bottom of the second rectification column.

Abstract: Crude acetonitrile is purifed to 99+ weight percent by a continuous distillation procedure.

Abstract: Metal chlorides such as aluminum chloride (AlCl.sub.3) are separated from a mixture containing metal chlorides including AlCl.sub.3 and ferric chloride (FeCl.sub.3). In order to effect this separation, the mixture is subjected to a fractional distillation process utilizing an array of distillation columns. According to this process, the mixture is introduced into a first distillation column which is operated at temperatures and pressures sufficient to separate FeCl.sub.3 from the mixture while avoiding the formation of a solid solution of FeCl.sub.3 and AlCl.sub.3 within the column. At least one additional distillation column is then employed to separate metal chlorides from the remaining mixture from the first column.