Abstract: A process for the separation of diisobutylene from tertiary butyl alcohol utilizing pressure swing azeotropic distillation to achieve the desired separation. The pressure swing azeotropic distillation takes advantage of the fact that different azeotropes are formed at different pressures. Isobutylene in C4 streams is oligomerized in the presence of tertiary butyl alcohol to produce the diisobutylene. Tertiary butyl alcohol is present in the dimerization because it improves the selectivity to the dimer (diisobutylene) by suppressing further reaction to the trimer or higher. The diisobutylene is separated from the tertiary butyl alcohol utilizing two distillation columns. The first distillation is operated at a higher pressure than the second such that the minimum boiling azeotropes of tertiary butyl alcohol and diisobutylene have different concentrations of tertiary butyl alcohol. Diisobutylene is removed as bottoms from the first distillation column and unreacted C4's are removed as overheads at 60-130 psig .

Abstract: A process is provided herein for the high yield production of high purity glacial methacrylic acid (“HPMAA”) that is substantially pure, specifically 99% pure or greater with a water content of 0.05% or less.

Abstract: A distillation apparatus includes a column body; a partition for dividing the interior of the column body; a first distillation section composed of an enriching section and an exhaust section; a second distillation section composed of an enriching section formed above an upper end of the first distillation section, and an exhaust section located adjacent to the enriching section of the first distillation section; a third distillation section composed of an enriching section located adjacent to the exhaust section of the first distillation section, and an exhaust section formed below a lower end of the first distillation section; a condenser; a negative pressure generation system for generating a negative pressure to thereby withdraw vent gas; a gas cooler for cooling the vent gas; a first discharge system disposed at the side of the column body and adapted to discharge liquid rich in a medium-boiling-point component formed from a high-melting-point material; and a second discharge system disposed at the botto

Abstract: A method is provided for preventing an easily polymerizable substance from being polymerized in a thin-film type evaporating device by supplying a solution of the substance to the evaporating heating surface of the device by the centrifugal force of a stirring rotary shaft, characterized by mixing a distilled vapor of the substance with a molecular oxygen-containing gas and supplying the extracted liquid or a solution having lower viscosity than the extracted liquid to a feed raw material inlet thereby adjusting the quantity of a wetting liquid per unit length of the surface in the range of 0.02-2 m3/mHr. In the evaporation of the substance by the use of the device, a method for preventing the substance from polymerization is provided.

Abstract: The useful reaction products in an output stream from an ammonolysis reactor are separated in a manner which minimizes the time during which high boiling polyamide intermediate material(s) are in contact with the amine-functional monomer product(s) or with the reactive monomer products in the stream.

Abstract: Process for the production of a hydrofluoroalkane, according to which hydrofluoroalkane comprising organic impurities is subjected to at least two distillations.

Abstract: Process for the recovery of a purified adiponitrile (ADN) from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine, utilizing two sequential distillations: (1) a first distillation in which the mixture is distilled in a distillation column at a head pressure that causes at least 7% of the ADN to go into the distillate, along with bishexamethylenetriamine (BHMT) and 2-cyanocyclopentylideneimine (CPI), and (2) a second distillation in which the distillate from the first distillation is distilled in a second distillation column at a head pressure sufficient to cause minimum-temperature azeotropy between ADN and BHMT, thereby allowing the majority of the BHMT and CPI to be removed from the second distillation as distillate, and ADN, substantially free of both BHMT and CPI, to be removed as bottoms.

Abstract: A tert-C4-C8-alkyl (meth)acrylate is prepared by reacting (meth)acrylic acid with an olefin of the formula 1

Abstract: In a process for the continuous fractional distillation of mixtures comprising tetrahydrofuran, &ggr;-butyrolactone and/or 1,4-butanediol to give at least three fractions, the fractionation is carried out in an assembly of distillation columns comprising at least one dividing wall column or at least one assembly of thermally coupled conventional distillation columns.

Abstract: There is provided a process for recovering tetrafluoroethylene wherein an amount of energy required to obtain TFE is reduced.

Abstract: A method and apparatus for purifying acetonitrile from low grade acetonitriles. Low grade acetonitrile from DNA synthesis, HPLC and pharmaceutical drug manufacturing process wastes which comprise acetonitrile, a first set of impurities having a lower boiling temperature than acetonitrile and a second set of impurities having a boiling temperature greater than acetonitrile are processed to produce a purified acetonitrile by first introducing the low grade acetonitrile into a first distillation column and separating the acetonitrile and first set of impurities from the second set of impurities, the acetonitrile and first set of impurities being drawn as a vapor from the first distillation column, the second set of impurities being produced as the first distillation column bottoms.

Abstract: A mixture of propylene oxide and methanol is separated by liquid/liquid extraction using water and a hydrocarbon such as n-octane as extractive solvents.

Abstract: A process for removing impurities from 3-(2′-acetoxyethyl)dihydro-2(3H)furanone (I), where the 3-(2′-acetoxyethyl)dihydro-2(3H)furanone containing the undesirable impurities is initially prepared in a manner known per se by acetylation of 3-(2′-hydroxyethyl)dihydro-2(3H)furanone and the resulting product is subsequently subjected to a distillation or rectification, includes carrying out the distillation or rectification in a plurality of steps, where high-boiling impurities are removed in a first step, the product which is drawn off via the top is subsequently subjected to at least one further step in which low-boilers and intermediate boilers are drawn off via the top and the desired pure I is obtained as bottom product.

Abstract: A process for the purification of difluoromethane comprising: (a) subjecting a mixture comprising at least difluoromethane (HFC-32) and dichlorodifluoromethane (CFC-12) to a first distillation step in which a majority of either CFC-12 or HFC-32 is concentrated in a first distillate and a majority of the other component is concentrated in a first bottoms; and (b) subjecting the first distillate in step (a) to at least one additional second distillation step conducted at a different pressure in which a majority of the component concentrated in said first distillate is concentrated in a second bottoms and in which the other component is concentrated in a second distillate; and (c) recovering purified HFC-32 from one of said first or second bottoms.

Abstract: There is provided a process for producing Guerbet alcohols not containing any heavy metals or soaps, wherein primary and/or secondary alcohols having 2 to 30 carbon atoms are condensed at elevated temperature in the presence of alkaline catalysts and/or heavy metal catalysts while eliminating the reaction water, and the reaction product is immediately separated by distillation without any additional purification.

Abstract: A method and apparatus for purifying acetonitrile from low grade acetonitriles. Low grade acetonitrile from DNA synthesis, HPLC and pharmaceutical drug manufacturing process wastes which comprise acetonitrile, a first set of impurities having a lower boiling temperature than acetonitrile and a second set of impurities having a boiling temperature greater than acetonitrile are processed to produce a purified acetonitrile by first introducing the low grade acetonitrile into a first distillation column and separating the acetonitrile and first set of impurities from the second set of impurities, the acetonitrile and first set of impurities being drawn as a vapor from the first distillation column, the second set of impurities being produced as the first distillation column bottoms.

Abstract: This invention concerns a process to provide high purity akylene carbonate though use of multiple distillations wherein the unused fractions are recycled to the reactor.

Abstract: A distillation apparatus includes a column body; a partition for dividing the interior of the column body; a first distillation section composed of an enriching section and an exhaust section; a second distillation section composed of an enriching section formed above an upper end of the first distillation section, and an exhaust section located adjacent to the enriching section of the first distillation section; a third distillation section composed of an enriching section located adjacent to the exhaust section of the first distillation section, and an exhaust section formed below a lower end of the first distillation section; a condenser; a negative pressure generation system for generating a negative pressure to thereby withdraw vent gas; a gas cooler for cooling the vent gas; a first discharge system disposed at the side of the column body and adapted to discharge liquid rich in a medium-boiling-point component formed from a high-melting-point material; and a second discharge system disposed at the botto

Abstract: In one embodiment, the present invention relates to a method of treating a solution containing hydroxylamine, involving subjecting the solution containing hydroxylamine to fractional distillation using a packed column thereby providing a first distillate; and subjecting the first distillate to flashover distillation thereby providing a second distillate containing a hydroxylamine solution. In another embodiment, the present invention relates to an ultrapure solution simply containing hydroxylamine, at least one stabilizer, and water.

Abstract: The invention relates to method for separating tocotrienol from a first tocol admixture by heating the first tocol admixture composed of a tocotrienol, at least one tocopherol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocol admixture composed of the tocotrienol, the tocopherol, the esterified fatty acid, and the unesterified fatty acid; distilling the second tocol admixture with the esterified fatty acid to remove the unesterified fatty acid from the second tocol admixture to produce a third tocol admixture composed of the tocotrienol and the tocopherol, with substantially removed unesterified fatty acid; distilling the third tocol admixture for a sufficient time and temperature to substantially remove the tocotrienol and tocopherol from the third tocol admixture to produce a fourth tocol admixture composed of the removed tocotrienol, tocopherol, and a non-tocol component; and extracting the tocotrienol from the fourth tocol admixture with an extraction solvent

Abstract: In a process for separating liquid mixtures comprising formaldehyde, trioxane, alcohol, hemiformal formed from the formaldehyde and the alcohol, usual minor components and up to 5% by weight of water, the liquid mixture is distilled batchwise or continuously at reduced pressure, atmospheric pressure or superatmospheric pressure in suitable apparatuses which are to be connected to one another in an appropriate manner, and the trioxane is produced in very high purity. The other materials of value, formaldehyde and alcohol, present in the mixture can likewise optionally be separated off and recycled or used otherwise, while the minor components are ejected.

Abstract: The invention relates to method for separating tocol from a tocol-containing admixture by heating the tocol-containing admixture composed a tocol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocol admixture composed of the tocol, the esterified fatty acid, and the unesterified fatty acid; distilling the tocol-containing admixture with the esterified fatty acid to remove the unesterified fatty acid from the tocol admixture to produce a tocol admixture composed of the tocol with substantially removed unesterified fatty acid; distilling the tocol admixture for a sufficient time and temperature to substantially remove the tocol from the tocol admixture to produce a tocol admixture composed of the removed tocol and a non-tocol component; and extracting the tocol from the tocol admixture with an extraction solvent composed of a polar, organic solvent that is miscible with water to produce a two phase system composed of a first phase containing the majority of the extract

Abstract: This invention concerns a process to provide high purity alkylene carbonate though use of multiple distillations wherein the unused fractions are recycled to the reactor.

Abstract: A method is provided for industrially advantageously and effectively separating 4M2B and 3M6B from a t-butylcresol mixture containing 2-t-butyl-4-methylphenol (4M2B), 2-tbutyl-5-methylphenol (3M6B), compounds having a lower boiling point than that of 4M2B and compounds having a higher boiling point than that of 3M6B derived from a m,p-cresol mixture.

Abstract: The present invention teaches an efficient and easier to operate distillation system to separate mixtures containing three or more components into streams enriched in one of the components. In this invention, a liquid stream enriched in the least volatile component is withdrawn from the bottom of one distillation column while a vapor stream enriched in the most volatile component is withdrawn from the top of another distillation column. Of these two distillation columns, the pressure of the distillation column with the bottom liquid enriched in the least volatile component is higher; and this higher pressure distillation column transfers at least two vapor streams from different locations to either one or more other distillation columns within the distillation system. For a ternary mixture, both the vapor streams are transferred to the distillation column with the top vapor enriched in the most volatile component.

Abstract: Neopentyl glycol hydroxypivalate (NGH) is isolated from a mixture containing NGH, lower- and higher-boiling products and inorganic salts and purified in a two-stage process, whereinin a first separation stage, the inorganic salts and part of the higher-boiling products are separated off in a wiped-film evaporator and a vapor stream consisting of NGH, lower- and higher-boiling products is discharged and fed to a heat exchanger and condensed therein,and, in a second separation stage, the resulting condensate is distilled in a rectification column from which NGH is taken off in a side stream and condensed. Further discharges of the rectification column containing lower-boiling products or higher-boiling products are separately taken off. The higher-boiling products which comprise residual NGH are partly or completely recycled to the lower region of the rectification column.

Abstract: Propylene oxide obtained by an epoxidation process which uses methanol as a solvent may be effectively treated to remove acetaldehyde by subjecting the crude epoxidation reaction product to fractional distillation. The methanol solvent is utilized during such distillation to lower the relative volatility of the acetaldehyde impurity, thereby making it possible to obtain a bottoms fraction containing substantially all the acetaldehyde. Purified propylene oxide having a reduced acetaldehyde concentration is removed as an overhead stream. Water may also be effectively separated from the propylene oxide using this procedure.

Abstract: Butanol and dibutyl ether are separated from a mixture containing water, dibutyl ether and n-butanol, 2-butanol and/or isobutanol by a process in whicha) the mixture is introduced into a first distillation column, essentially butanol is separated off at the bottom of this distillation column and the mixture taken off at the top of the distillation columnb) is introduced into a second distillation column and essentially dibutyl ether is separated off at the bottom of this second distillation column and the mixture formed at the top of the second distillation column is removed,c) the second distillation column being operated at a higher pressure than the first distillation column and at least one of the two mixtures taken off via the top of the distillation columns being subjected to phase separation, only the organic phase separated off being fed to the second distillation column in the case of phase separation downstream of the first distillation column, and separation into an aqueous and an organic phase als

Abstract: A process is disclosed for producing 1,1,2,2,3,3,4,4-octafluorobutane. The process involves (a) reacting a mixture comprising 2,2,3,3-tetrafluorobutane and chlorine to form a mixture of chloro-compounds wherein compounds of the formula C.sub.4 H.sub.x Cl.sub.6-x F.sub.4 (where x is 0 or 1) comprise at least about 50 mole % of the mixture of chloro-compounds; (b) contacting certain chloro-compounds from (a) and hydrogen fluoride with a fluorination catalyst to form a mixture of fluoro-compounds; and (c) contacting certain fluoro-compounds from (b) and hydrogen with a hydrogenolysis catalyst to produce CHF.sub.2 CF.sub.2 CF.sub.2 CHF.sub.2. Sufficient chloro-compounds formed in (a) and sufficient fluoro-compounds formed in (b) are recycled to provide a selectivity to CHF.sub.2 CF.sub.2 CF.sub.2 CHF.sub.2 of at least about 75% based upon the moles of CH.sub.3 CF.sub.2 CF.sub.2 CH.sub.3 reacted in (a).

Abstract: This invention relates to a process for working up the alcohol-containing wastewater which is obtained in the hydrolysis of silanes of the general formula IR.sup.1.sub.a SiCl.sub.b (OR.sup.2).sub.4-a-b (I),whereR.sup.1 are hydrogen atoms or identical or different monovalent, unsubstituted or halogen-substituted, SiC-bonded C.sub.1 -C.sub.18 -hydrocarbon radicals,R.sup.2 are identical or different monovalent C.sub.1 -C.sub.10 -hydrocarbon radicals,a is 0, 1, 2 or 3, on average from 0.3 to 1.9, andb is 0, 1, 2, 3 or 4, on average from 0.0 to 3.0,with the proviso that the sum a+b is on average at most 3.5, for the preparation of silicone resins, wherein, in the first step, the wastewater is made alkaline by addition of alkali and, in the second step, the alcohol is removed from the resulting alkaline solution or suspension by injection of steam.

Abstract: Cyclohexene is separated from a mixture of cyclohexene and at least one of cyclohexane and benzene by subjecting the mixture to extractive distillation in the presence of an extraction solvent the formula: ##STR1## wherein R.sup.1 and R.sup.2 each is a C.sub.1-10 alkyl group or hydrogen, and n is an integer of from 2-4, thereby preparing a fraction rich in cyclohexene.

Abstract: A process is provided for the isolation of (meth)acrylic acid from a mixture containing (meth)acrylic acid as the main component and lower aldehydes as secondary components by rectification in a rectification column having a stripping section and a rectification section, wherein the starting mixture containing the (meth)acrylic acid to be isolated by rectification is not fed directly to the rectification column but is first passed into a heated dwell vessel which is connected to the vapor side of the rectification section of the rectification column and in which the starting mixture is kept at the boil and, instead of the starting mixture as such, the bottom liquid of the dwell vessel is fed to the rectification column.

Abstract: Use of labels for labelling rubber parts, in particular tires, comprisinga) a base layer comprising a laser-inscribable, co-vulcanizable, pale rubber blend whichb) contains an additive which produces a color change on laser irradiation,c) is, if desired, covered by a protective covering which is transparent in the visible region and in the near IR region, andd) is, if desired, coated on one side with a self-adhesive composition whiche) is, if desired, covered by a release paper or a release film.

Abstract: A polymerizable grade of ethylene is recovered from an olefin-containing composition, prepared by the conversion of a methoxy compound to olefins, by a process which significantly reduces the requirements of the demethanizer distillation column through which hydrogen and methane are eliminated as impurities from the ethylene product without suffering economically unacceptable losses of ethylene to the hydrogen-methane fraction that is separated. The invention also provides for a C-2 splitter column of simplified requirements.

Abstract: Provided is a novel method and system for separating and purifying perfluorocompounds (PFCs). The method comprises the steps of: (a) introducing a perfluorocompound-containing gas stream into a first distillation column; (b) removing a light product from the first column, and removing a heavy product from the first column; (c) introducing the first column light product into a second distillation column; (d) removing a light product from the second column, and removing a heavy product from the second column; (e) introducing the second column light product into a third distillation column; and (f) removing a light product from the third column, and removing a heavy product from the third column. The method and system can be advantageously used in the treatment of exhaust gases from semiconductor processing tools, and results in highly purified PFCs which can be recycled, thereby avoiding the release of PFCs into the atmosphere.

Abstract: A process for removing trioxane from a liquid mixture containing trioxane, water and formaldehyde, which includes distilling the liquid mixture in a first distillation stage at a low pressure, distilling the resulting distillate in a second distillation stage at a higher pressure and taking off trioxane as bottom product.

Abstract: Caprolactam is recovered from oligomers and/or polymers of caprolactam by cleavage of oligomers and/or polymers of caprolactam and subsequent working up by distillation of the caprolactam obtained in the cleavage, by a process including(a) cleaving oligomers and/or polymers of caprolactam to obtain an aqueous reaction mixture which contains caprolactam,(b) removing water from the reaction mixture obtained under (a) to obtain a residue,(c) distilling the residue obtained under (b) in an acidic medium and(d) then distilling the distillate in an alkaline medium to obtain caprolactam, or(c') distilling the residue obtained under (b) in an alkaline medium and(d') then distilling the distillate in an acidic medium to obtain caprolactam.

Abstract: A purification process for cyclic formals, in which water is efficiently removed from a crude cyclic formal, namely, a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only a very small amount of water.The purification process for cyclic formals is characterized by the following two purification steps:(1) Supplying a mixture of a cyclic formal and water into a distillation tower at a supply position, and effecting distillation while supplying a hydrophilic solvent (A) having a boiling point from 180.degree. to 250.degree. C. at a position higher than the supply position of the mixture to take out a cyclic formal (X) containing 100 to 5000 ppm of water as a distillate, and(2) Distilling the cyclic formal (X) obtained in step (1) or treating it with a dehydrant to obtain a purified cyclic formal (Y) which contains less water than in the cyclic formal (X).

Abstract: A process for preparing essentially pure 3-chlorophthalic anhydride from a mixture in which 3-chlorophthalic anhydride is present in addition to 4,5-dichlorophthalic anhydride, which involves first distilling off a mixture of 3-chlorophthalic anhydride and 4,5-dichlorophthalic anhydride, so that the obtained bottoms is essentially free of 4,5-dichlorophthalic anhydride, and then by distillation of the obtained bottoms, recovering 3-chlorophthalic anhydride in a second distillation step. The starting mixture is preferably prepared without solvent in a melt by incomplete chlorination of phthalic anhydride using FeCl.sub.3 as a catalyst.

Abstract: An extractive distillation process using a high boiling polyol such as glycerol is employed for separating high purity catechol, 3-methylcatechol and 4-methylcatechol from a high boiling, pitch-like dihydric phenol fraction. Fractional distillation first separates an impure overhead mixture of the catechol and 3-methylcatechol and an impure 4-methylcatechol bottoms. The impure overhead is extractively distilled to remove impurities and then extractively distilled again to separate the catechol and 3-methylcatechol. This produces a pure overhead of 3-methylcatechol and a bottoms of catechol and polyol which is distilled to recover the catechol and recycle the polyol. The impure 4-methylcatechol is distilled to remove residual material and then extractively distilled to remove impurities. The resulting mixture of 4-methylcatechol and polyol is distilled to recover the pure 4-methylcatechol and to recycle the polyol.

Abstract: The invention is a process for reducing capital and energy costs in ethylene recovery. Moderate pressure processing and thermally coupled fractionation steps are achieved through the use of integrator columns. Ethylene separation from cracked gas originating from ethane through gas oil feeds can now be done with thermodynamically efficient fractionation at capital cost competitive with low efficiency designs. Acetylene hydrogenation may be done before demethanization where desired, and dephlegmation is preferred to accomplish high-efficiency rectification of hydrogen and methane from ethylene. Open loop heat pumps can optionally be incorporated into the ethane/ethylene splitter fractionation step, whose desirability is controlled by optimization of capital and energy costs.

Abstract: A process by which iodine compounds contained in crude acetic anhydride or a mixture of crude acetic anhydride and crude acetic acid can be converted into methyl iodide having a low boiling point and which can be separated by distillation and efficiently removed by the combination of the conversion step with the heat treatment step and distillation step. The process includes the steps of heat-treating the crude acetic anhydride or the mixture of crude acetic anhydride and crude acetic acid in the presence of methanol and/or methyl acetate in a treatment tank and distilling the heat-treated crude acetic anhydride or the heat-treated mixture of crude acetic anhydride and crude acetic acid, in the presence of an alkali metal salt and/or an alkaline earth metal salt if necessary.

Abstract: Vinyl formate containing formic acid, acetaldehyde and water following synthesis is separated from formic acid and water in a first distillation stage and from acetaldehyde in a second stage to give pure vinyl formate.

Abstract: A thermomechanically integrated distillation column and method for the separation of ethylene from ethane and other close-boiling light hydrocarbons. The column has a plurality of sections operated at successively lower pressures from a high pressure subcritical section to a superatmosphere bottoms product zone. Bottoms liquid from the high pressure and intermediate sections are flashed in respective cooling loops to about the pressure of the section of next lower pressure, vaporized in heat exchange with an overhead condensing zone and introduced to the top stage of next lower pressure section. Vapor from the intermediate sections and the bottoms product zone are compressed in respective compression loops and fed to the bottom stage of the section of the next higher pressure. External refrigerant can be supplied to the overhead condensing zone for trim as needed for control purposes.

Abstract: Crude propylene oxide is purified by a distillation process wherein it is (a) extractively distilled in a first column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a first overhead fraction comprising propylene oxide, C.sub.5 -C.sub.7 hydrocarbons, methanol, water and oxygen-containing impurities, (b) wherein the first overhead fraction is separated in a plurality of intermediate distillation columns to provide an intermediate propylene oxide overhead fraction consisting essentially of propylene oxide and water, and (c) the intermediate propylene oxide overhead fraction is charged to a final distillation column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a final overhead fraction consisting essentially of propylene oxide.

Abstract: A stream of raw phenol, coming from the acidic cracking of cumene hydroperoxide, is purified by a process of extractive distillation carried out in the presence of acetophenone.

Abstract: Impure propylene oxide is purified by a distillation process wherein it is (a) extractively distilled in a first column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a first overhead fraction comprising propylene oxide, C.sub.5 -C.sub.7 hydrocarbons methanol, water and oxygen-containing impurities, (b) wherein the first overhead fraction is separated in a second column into a second overhead fraction comprising most of the pentanes, pentenes and oxygen-containing impurities and a partially purified propylene oxide bottoms fraction comprising propylene oxide, hexenes, hexanes, and only residual quantities of pentenes and pentanes, (c) wherein the partially purified bottoms fraction is extracting distilled in a third column using a C.sub.7 -C.sub.

Abstract: The separation of ethyl tertiobutyl ether from mixtures with ethanol is based on heteroazeotropic distillation with water as the entrainer using two distillation columns, coupled with an overhead decanter. Purified ethanol is collected from the bottom of the first column and purified ETBE from the bottom of the second column. The separation method may be incorporated into an ETBE production unit in which isobutene (contained in a C.sub.4 -cut from steam cracking, catalytic cracking, or dehydrogenation of isobutane) is etherified by ethanol. Ethanol separated from the ETBE is then recycled to the etherification zone.

Abstract: The present invention provides a continuous method of purifying eicosapentaenoic acid and esters of eicosapentanoic acid, comprising (a) fractionally distilling a starting mixture containing eicosapentaenoic acid or esters of eicosapentaenoic acid using a system of at least three distillation columns connected in flow arrangement to separate a fraction containing eicosapentaenoic acid or esters of eicosapentaenoic acid and other C.sub.20 fatty acids from a fraction containing lower-number carbon fatty acids and from a fraction containing higher-number carbon fatty acids, and (b) continuously collecting the fraction containing eicosapentaenoic acid or esters of eicosapentaenoic acid, wherein the pressure in the distillation columns is maintained at 10 Torr or below and wherein the bottom temperature of the distillation columns is maintained at 210.degree. C. or below.

Abstract: The present invention provides a method of removing impurities from a stream of silane, SiH.sub.4. Most notably, the present invention provides a method of removing ethylene from a silane stream by converting the ethylene to ethylsilane in the presence of a molecular sieve and distilling the desired silane from the ethylsilane contaminant.