Abstract: Purified methanol is produced by distilling a water methanol mixture in (a) a first column from which is taken a product methanol stream at an upper level, weakly aqueous methanol as a side stream and water as bottoms and (b) a second column in which that weakly aqueous methanol is separated into an overhead product stream and aqueous methanol bottoms. The first column may be preceded by a preliminary volatiles-removal column. The process is economical in heat consumption, especially when methanol vapor from the second column is heat-exchanged with the feed or bottoms of the first column.

Abstract: The instant invention is directed to a process for the production of diisocyanatodiphenyl methane isomers having an adjusted content of chlorine compounds comprising:(a) separating diisocyanatodiphenyl methane isomers from a polyisocyanate mixture of the diphenyl methane series in a first distillation stage,(b) subjecting said separated isomers to a second distillation stage using a recycle ratio of from 0.1 to 10 and wherein from 0.5 to 10% by weight of the feed into said second distillation stage is run off as the sump product,(c) subjecting the head product of said second distillation stage to a third distillation stage whereby readily volatile impurities are freed therefrom, and(d) working up the sump product of said third distillation stage to obtain purified 4,4'-diisocyanatodiphenyl methane and, optionally, purified 2,4'-diisocyanatodiphenyl methane.

Abstract: According to the present invention an impure liquid containing ethylene glycol or propylene glycol, lower carboxylate esters of the glycol, water, carboxylic acid and glycol-azeotroping agent is treated for removal of substantially all of said glycol-azeotroping agent by a process which comprises distilling the impure liquid in a distillation zone to form an overheads product comprising water and glycol-azeotroping agent and a bottoms product comprising the glycol, esters and carboxylic acid, which is substantially free of said glycol-azeotroping agent, said bottoms product containing water in an amount of at least about 1 weight percent of the amount of water passed to said distillation zone with said impure liquid.

Abstract: A process for dehydrating an essentially one-phase wet solvent stream obtained in a solvent dewaxing-solvent deoiling process, which solvent stream contains at least 60% toluene with the balance being water and methyl ethyl ketone (hereinafter MEK), is dehydrated by (a) fractionally distilling to produce a bottom fraction of anhydrous MEK-toluene solvent and an overhead fraction containing all the water originally present in the wet solvent stream; (b) condensing and separating said overhead fraction into a toluene-containing, water-lean phase, which is used as reflux in step (a), and a toluene-free, MEK-containing, water-rich phase; (c) extracting into a hydrocarbon stream some MEK from said water-rich phase and from the condensed azeotropic mixture recycled from step (g) hereinafter; (d) recovering from step (c) a second water-rich stream, which water-rich stream contains the MEK not extracted into said hydrocarbon stream; (e) azeotropically distilling said second water-rich stream so as to obtain water as

Abstract: An energy efficient process for the separation of two close boiling point components contained in a multi-component feed stream. The feed stream is distilled in a first column to produce a relatively light fraction containing substantially all the more volatile close boiling point component, along with part of the less volatile close boiling point component and a bottoms product. The relatively light overhead fraction from the first column is fed to a second column to produce an overhead product, consisting substantially of the more volatile close boiling point component and a bottoms product consisting substantially of the less volatile boiling point component. The bottoms product from the first column is fed to a third column to produce an overhead vapor consisting substantially of the less volatile close boiling point component, which overhead vapor is passed to the second column to supply part of the reboiling energy requirements for said column.

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

Abstract: The separation of acrylic acid from a mixture of acrylic acid and acetic acid found in the reaction product stream obtained in the process of producing acrylic acid by the oxidation of propylene or acrolein is improved by removing a vapor sidestream from the solvent recovery column found in the process. Acetic acid is then separated from this stream without the addition of external heat.

Abstract: Crude phenol is recovered from CHP reaction products by continuously feeding to a main column separating in its uppermost section phenol from crude acetone, this fraction being removed overhead, and in the lower section crude phenol from higher boilers, including acetophenone and carbinol, the crude phenol being removed as a sidestream fraction from the main column at a point in the column above the feed-point wherein the total concentration of acetophenone plus carbinol is less than 1,000 ppm and the higher boiling compounds being removed as a base fraction.

Abstract: A process for recovering alkoxyketone compounds from mixtures of the alkoxyketone compound and the corresponding 1-alkoxy-2-alkanol compound by extractive distillation with diols, triols and polyols as extractants.

Abstract: Ethylene glycol esters or propylene glycol esters are recovered from their mixtures with high- and low-boiling organo-halogens by (1) distilling the mixture in a first distillation zone to form a first bottoms stream comprising the high-boiling organo-halogen impurities and a first overhead stream comprising the ethylene glycol esters or propylene glycol esters together with the low-boiling organo-halogen impurities, and (2) distilling at least a portion of the first overhead stream in a second distillation zone to form a second overhead stream containing the low-boiling organo-halogen impurities and a second bottoms stream comprising the desired ethylene glycol esters or propylene glycol esters having a substantially reduced concentration of the organo-halogen impurities.

Abstract: Ethylene glycol or 1,2-propylene glycol contained in mixtures with lower carboxylate esters of glycol, e.g. as produced by hydrolysis of the esters, is recovered by distillation of the mixtures with a hydrocarbon forming a minimum boiling azeotrope with the ethylene dlycol or 1,2-propylene glycol, the hydrocarbon being maintained in an inert atmosphere in the system.

Abstract: Methyl tertiary butyl ether may be recovered from etherification reaction effluent by azeotropic distillation to recover methanol-ether azeotrope overhead which is water-washed to give pure ether raffinate plus ether-methanol bottoms, the latter being azeotropically distilled to yield ether-methanol overhead which is recycled to water-washing.

Abstract: A lower carboxylic acid such as acetic acid is separated and recovered from an aqueous medium by the steps which include contacting, in an extraction zone, the aqueous medium with an extracting agent such as trioctyl phosphine oxide dissolved in an organic solvent such as a mixture of paraffins having a boiling range of about 160.degree. C. to 175.degree. C.

Abstract: A method and apparatus for separating a predetermined fraction from a crude oil includes preheating the crude oil to vaporize a portion, and feeding the two-phase crude to a first stage flash evaporator. In the first stage evaporator, a vapor portion is separated from residual liquid and the residual liquid is used by means of heat exchange to preheat the crude oil. The vapor fraction from the first stage evaporator has an approximate 90% ASTM distillation temperature about 50-60.degree. F higher than the first stage evaporator temperature. The vapor fraction is condensed to form a condensate, and the condensate is conveyed to a stripping column for mass transfer with ascending vapors from a second stage boiling type evaporator. The second stage evaporator is operated at a vaporization temperature approximately equal to the 5% ASTM vaporization temperature of the predetermined petroleum fraction collected as liquid from the second stage evaporator.

Abstract: Herein are disclosed an improved method and apparatus for separating a mixture of liquids of differing volatilities by fractional distillation in a plate-type apparatus. Plates consisting at least in part of a porous structure having capillary-type passages extending between openings on one side of the plate and openings on the other side of the plate are employed. The capillary-type passages are adapted to be wetted and filled at least in part by the liquid condensate resulting from the condensation of a vapor mixture, with the consequent formation of menisci in the capillary-type passages and the generation of capillary pressures that cause the condensed liquid to be lodged within the capillary-type passages and transmitted through the plate while preventing the passage of vapor.

Abstract: A process for recovering maximum amounts of styrene from hydrocarbon fractions produced by thermal cracking of hydrocarbons. The cracked products are subjected to quench cooling and in a separating column separated into a bottom fraction comprised predominantly of hydrocarbons with 9 and more carbon atoms and into a top fraction comprised predominantly of hydrocarbons having less than 9 carbon atoms. The top fraction is fed to a cooling and separating device wherein a cracked gasoline fraction is recovered from which fraction styrene is recovered by fractionation. The cracked gasoline fraction from the separating device can be combined with the hydrocarbon condensates from the first and second compressor stages of a multistage compressor in which the vaporous fraction from the cooling and separating device is compressed.

Abstract: A fluid mixture, such as pyrolysis gasoline, is fractionated into at least two aromatic-rich streams. These streams are introduced into an extractive distillation column at different elevations, with the stream containing the highest boiling aromatic being introduced at the highest elevation.

Abstract: A C.sub.4 -hydrocarbon feedstream containing butenes, butadiene, and vinylacetylene is subjected to a first extractive distillation with a selective solvent to remove butenes and a first portion of vinylacetylene as the extract; by the extraction with a minor quantity of methylethyl ketone in the selective solvent in this step, it has been found that a major portion of the vinylacetylene can be rejected, together with the butenes in the rich extract and that simultaneously the quantity of butadiene extracted could be considerably reduced; in a second extractive distillation the butadiene-rich raffinate of the first extractive distillation is further purified by extractive distillation using a mixture of sulfolane and methylethyl ketone as the solvent; after solvent stripping, the butadiene stream is finally purified in a fractionation step, wherein further vinylacetylene is removed.

Abstract: The relative volatility of cis-1,4-dichlorobutene-2 to trans-1,4-dichlorobutene-2 is increased when these two isomers are fractionated in the presence of 3,4-dichlorobutene-1.

Abstract: Ethylene glycol or 1,2-propylene glycol contained in mixtures with lower carboxylate esters of the glycol is recovered by azeotropic distillation of the mixtures with an azeotroping agent which is a hydrocarbon which has a boiling point at atmospheric pressure above 190.degree. C but at most about 220.degree. C and is free from linear secondary and tertiary hydrogen atoms.

Abstract: Normal alpha-olefins containing minimum paraffin content are prepared from hydrocarbon wax streams by a process which comprisesPreheating a charge wax stock to thermal cracking temperature;Passing said charge wax stock during said preheating operation through the intermediate temperature range of 625.degree.-800.degree. F in a time less than about 8 seconds whereby the desired product contains a decreased proportion of paraffin impurities;Thermally cracking said preheated charge wax stock in vapor phase in the presence of steam at thermal cracking conditions thereby forming a product stream cracking effluent containing desired product n-alpha olefins containing 6-18 carbon atoms together with decreased proportion of paraffin impurities;Separating said desired product n-alpha olefins containing 6-18 carbon atoms from said product stream cracking effluent; andMaintaining the Severity Value of said product stream cracking effluent during said separating less than about 66.5.

Abstract: A process is provided for purification and drying of acetic acid containing water and methyl iodide and hydrogen iodide as contaminants. The process comprises distillation in a two-zone system wherein the major part of the methyl iodide and hydrogen iodide and some water are removed as overhead and bottoms, respectively, from the first zone; a stream from the middle section of the first zone is introduced into a second zone into which there is also introduced a stream of methanol; and a stream of dry purified acid is recovered from the bottom of said second zone. The process provides both for the recovery of the iodine components and the methanol added for re-use in production of additional acetic acid by the reaction of methanol and/or methyl acetate with carbon monoxide in contact with a catalyst system formed on mixing of a rhodium or iridium component and an iodine component in the presence of carbon monoxide.

Abstract: Dioxane is produced by reaction of ethylene glycol or a polyethylene glycol using an acid catalyst. The reaction product containing dioxane, water and byproducts is subjected to extractive distillation with a high-boiling agent which is miscible with water.

Abstract: A process for producing 2-methyl-3-buten-2-ol by reacting isoprene with a hydrohalide and then with an aqueous base and then distilling the aqueous mixture in the presence of excess base to maintain the reaction mixture during distillation at a pH of at least 4.

Abstract: Methyl tertiary butyl ether may be recovered from etherification reaction effluent by azeotropic distillation to recover methanol-ether azeotrope overhead which latter is azeotropically distilled in the presence of n-pentane to give pure ether bottoms substantially free of water and methanol.