Abstract: A process for purifying a crude ester containing dimethyl terephthalate, includes flash distilling a mixture including para-xylene and methyl para-toluate, and separating the crude ester into fractions. By separating the crude ester with a distillation column containing structured packing and using a lower bottom temperature, product yield is increased, and the process is made more economical.

Abstract: Process technology is described making possible substantial improvements in the separation and recovery of highly pure vinyl aromatic monomers, notably styrene. A number of design, construction and operational features are made available for selection and use both for new plant facilities and for upgrading existing plant facilities. One major aspect of the invention is reduction in retention or residence times in the distillation towers. In another embodiment, a startup process comprises (i) introducing a feed comprising vinylaromatic monomer, polymerization inhibitor, aromatic hydrocarbon components having boiling points above that of the vinylaromatic monomer to a packed distillation column, said column having a maximum theoretical .DELTA.

Abstract: A compact apparatus of the distillation of solvent from a mixture of the solvent with oil seed for the extraction thereof according to the invention, the primary module includes a vapor scrubber forming a vapor contactor, a main evaporator and a first condenser while the secondary module has an after evaporator combined in a unit with the stripping column and the second condenser.

Abstract: A process for preparing refined acrylic esters, the process including steps of distilling an acrylic ester containing stream in the presence of hydroquinone or substituted hydroquinone, at a concentration in the range of 200 to 5000 ppmw, wherein the distillation is carried out in the presence of 0.001 to 1.0 % v, on the vapor phase, of oxygen.

Abstract: Natural cresylic acid is processed to remove neutral oil impurities by countercurrent liquid/liquid extraction using a heavy phase solvent of a mixture of glycerol and another polyhydric alcohol, preferably triethylene glycol. The light phase solvent is a light paraffinic or cycloparaffinic hydrocarbon.

Abstract: The process for the final evaporation has at least two evaporation appliances. These appliances are coupled in series with respect to the black liquor and in parallel with the live steam (primary steam), which drives the evaporation, and with the secondary steam that is generated by the evaporation. The pressure of the primary steam that is supplied to the appliance(s) where the liquor concentration is at the highest concentration is greater than the pressure of the primary steam supplied to the other appliances where the liquor concentration is not so high.

Abstract: A process and apparatus for improving the thermal efficiency of a steam turbine power generating plant while simultaneously desalinating seawater or brine and purifying water which contains minerals, salts, and other dissolved solids. Exhaust gases from a power plant is heat exchanged against water in a secondary ecomomizer which circulates water at a temperature near, or slightly above the dewpoint of the combustion exhaust of the high-pressure boiler. The heated water is flashed to produce low-pressure steam. The low-pressure steam is condensed against the last effect of a multi-effect desalinization unit. Steam from the first effect of the desalination unit is condensed against steam condensate from the power plant turbine to preheat the condensate and thereby recover heat from the power plant's exhaust gas. Salinous water is fed to the multi-effect desalinization unit to produce fresh water and a concentrated brine.

Abstract: A method for the on-site reprocessing of isopropyl alcohol used in semiconductor manufacturing, to generate an ultradry and ultrapure isopropyl alcohol. This ultradry and ultrapure isopropyl alcohol is produced through a pervaporation step, followed by double distillation. In the first distillation step, an autonomous azeotropic self-stripping distillation column is used to produce an ultradry and partially purified isopropyl alcohol. In the next step, the isopropyl alcohol is distilled in an overhead product distillation column, to produce an ultrapure and ultradry isopropyl alcohol. Alternatively, if the feed isopropyl alcohol contains less than 2000 ppm water, the pervaporation step may be omitted.The resulting isopropyl alcohol has between a high of 100 parts per million (ppm) and a low of 0.1 ppm of water in the isopropyl alcohol. It also has zero particles per milliliter of a size larger than 2.0 microns, zero to 2 particles per milliliter of a size of 0.5 micron to 2.

Abstract: Disclosed is a process for the separation of tar and non-volatile reagents from a reaction mixture formed when chlorinated carbon compounds are allowed to react with anhydrous hydrogen fluoride in a liquid phase to form fluorinated carbon compounds. The disclosed process leaves tar essentially free of HF and in a form allowing for safe, easy, and economical transfer and disposal.

Abstract: The disclosure relates to separating 1,1,1-trifluoroethane (HFC-143a from fluorocarbon impurities by using extractive distillation with an extractive agent comprising an alcohol. Examples of suitable extractive agents comprise at least one member from the group of methanol, butanol, ethanol, propanol, their isomers and cyclic compounds thereof, among others.

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 process for preparing bisphenol A which has a purity of at least 99.95 wt. % of p,p-bisphenol A (BPA). Thermally stable and colour-stable BPA purified in accordance with the invention produces improved thermal and colour stability and improved optical transparency in polymers such as e.g. polycarbonates prepared therefrom.

Abstract: Processes are provided for producing a pure grade of acrylic acid having residual aldehyde levels under 10 parts per million. The processes apply selected groups of amines sequentially and, preferably, continuously in selectively reducing, for example, acrolein and furfural, and may be advantageously conducted in the presence of maleic acid and maleic anhydride impurities.

Abstract: A process for the recovery of an acid in its anhydrous form from an aqueous solution containing the acid in its hydrated form. Adding to the solution a weak base in the form of a soluble salt of the acid and concentrating the solution containing the acid hydrate and the salt of the acid to a substantially water-free, acid-salt mixture. The acid is distilled off in its anhydrous form from the acid salt mixture.

Abstract: A continuous process for producing a pure grade of acrylic acid having residual aldehyde levels under 10 parts per million. The process applies two groups of amines sequentially and continuously in selectively reducing acrolein and furfural and may be advantageously conducted in the presence of maleic acid and maleic anhydride impurities.

Abstract: Amine mixtures generated during the production of diaminotoluene by hydrogenating dinitrated aromatic compounds are treated to separate high boiling materials from the desired amine products. In this process, any water of reaction and any solvent are first removed from the diaminotoluene isomer mixture (TDA mixture). The low-boiling TDA isomers are then separated using a TDA isomer distillation column. In the process of the present invention, the bottom phase remaining after the initial distillation contains a mixture of m-TDA and high-boiling materials. This bottom phase is separated and concentrated until the high-boiling material content is from approximately 25 to 60 wt. %. This concentrated bottom phase is then mixed with o-TDA in a ratio of 1:1 to 1:5 and a m-/o-TDA mixture is removed by distillation. The m-/o-TDA mixture thus recovered is then returned to the TDA isomer distillation column.

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 method of recycling and purifying cleaning chemicals used in the production of semiconductor circuits and containing hydrofluoric acid and or hydrochloric acid. Recycling of such chemicals is accomplished using separation and reconstitution steps Hydrofluoric acid and hydrochloric acid cannot be distilled directly from a chemical solution as they form azeotropes with water. A low vapor pressure substance such as sulfuric acid or phosphoric acid is used to break the azeotrope while increasing the purity of the recovered chemicals and decreasing disposal problems. The method is useable at the point of use of the chemicals.

Abstract: A process and apparatus for desalinating seawater or brine and purifying water which contains minerals, salts, and other dissolved solids while simultaneously generating power. The salinous water is heated in a boiler to form steam and a concentrated brine. The concentrated brine is removed from the boiler, the steam produced in the boiler is washed with fresh water to remove trace salts and inorganic materials, and water bearing trace salts and inorganic materials are returned to the boiler. The washed steam is expanded across a turbine to generate electrical or mechanical power which is utilized as a product. The steam exhausted from the turbine is collected and condensed, and one portion of the condensed water is utilized as a fresh water product and another portion of the condensed water is used as the wash water to wash the steam produced in the boiler. Energy efficiency is improved by heat exchanging the hot concentrated brine against the salinous feed water or by flashing the brine to produce steam.

Abstract: A process for the recovery of an acid in its anhydrous form from an aqueous solution containing the acid in its hydrated form. The process includes adding to the solution a weak base in the form of a soluble salt of the acid, and concentrating the solution containing the acid hydrate and the salt of the acid to a substantially water-free, acid-salt mixture. The acid is distilled off in its anhydrous form from the acid-salt mixture.

Abstract: A vapor compression distillation/product concentration device includes an evaporator/condenser core, with alternating boiling and condensing chambers with edge manifolds such that substantially the entirety of each plate surface is used as a heat transfer surface. Seals are conveniently formed between adjacent plates by laying a bead of liquid gasketing material such that as the plates are laid atop each other and cured, a waffle-like seal is formed surrounding the contact points between adjacent plates which interlocks the seal with the plates. A truly perpendicular fluid flow is achieved between the alternating boiling chambers and condensing chambers as each fluid traverses the entirety of each chamber in a unidirectional flow as it passes through the evaporator/condenser core.

Abstract: A process for treating C.sub.3 to C.sub.12 petroleum fractions, such as a light cracked naphtha to be used as an etherification feed stock in which H.sub.2 S is removed by distillation of at least the C.sub.3 fraction and mercaptans and diolefins are removed simultaneously in a distillation column reactor using a dual catalyst bed. The mercaptans and H.sub.2 S are reacted with the diolefins in the presence of a reduced nickel catalyst to form sulfides which are higher boiling than the portion of the feed which is fractionated to an upper hydrogenation catalyst bed of palladium for hydrogenating diolefins and acetylenes. The higher boiling sulfides are removed as bottoms along with heavier materials. Any diolefins not converted to sulfides and acetylenes are selectively hydrogenated to mono-olefins in the presence of a palladium oxide catalyst in an upper bed, producing overheads, substantially free of sulfur compounds, diolefins and acetylenes.

Abstract: The invention provides a continuous process for producing a pure grade of acrylic acid having residual aldehyde levels under 10 parts per million. The process applies two groups of amines sequentially and continuously in selectively reducing acrolein and furfural and may be advantageously conducted in the presence of maleic acid and maleic anhydride impurities.

Abstract: A method of purifying the oxidate product formed by the liquid phase oxidation of C.sub.4 -C.sub.8 paraffinic hydrocarbons comprises adding a strong acid catalyst to the oxidate product to catalyze the break down of Michael addition products of unsaturated carbonyls and carboxylic acids so that the carbonyls can be distilled off during the initial stages of purification.

Abstract: A method of separating a liquid mixture wherein the liquid mixture is heated; the heated liquid mixture is supplied to a pervaporation membrane module to separate a permeable component of the liquid; a portion of non-permeated liquid is circulated through a circulation pipe into a liquid mixture feeding pipe before a heater, and the remaining portion of the non-permeated liquid is extracted to the outside of the system, and wherein the temperature of the liquid in the liquid mixture feeding pipe in which the non-permeated liquid has been mixed with the liquid mixture or in the circulation pipe for the non-permeated liquid, is measured, and when the measured temperature is out of a predetermined range, new supply of the liquid mixture and/or extraction of the non-permeated liquid is stopped.

Abstract: The invention relates to a method and a device for ensuring the sterility of distillate in a multi-stage distilling machine. All feed water of the multi-stage distilling machine flows through a first column operating at the highest temperature so that the temperature of the feed water is equal to or greater than about 121.degree. C., about 131.degree. C., and about 141.degree. C., respectively, and the delay time after the feed water is removed from the first column and before its entry into the first column is at least about 8 minutes, about 0.8 minutes, 0.08 minutes, respectively. The delay produces the result that the distillate of every column of the multi-stage distilling machine is sterile, including that of the last column operating at the lowest temperature. The feed water flows through a first flow line from a second column to the first column, from the first column through a second flow line to a heat exchanger and returns from the heat exchanger through a third flow line to the first column.

Abstract: Process equipment is provided for separating ether, alcohol and hydrocarbon components from various etherifications of C.sub.4 or C.sub.5 isoolefins with an alcohol such as methanol or ethanol, and wherein identical process vessels are utilized for recovery of MTBE, ETBE, TAME, or TAEE. In use the process vessels are serially arranged in three zones. The first zone includes a first water wash vessel followed by a first fractionator and provides the ether product, the second zone includes a second wash vessel followed by a hydrocarbon stripper and recovers a stabilized hydrocarbon stream, the third zone includes a second fractionator which recovers an alcohol suitable for recycling.

Abstract: A process for recovering column bottom residues produced by distillation of ethylene glycol resulting from an aromatic polyester production process, involving treating the residues with an aromatic mono-alkyl ester and distilling the reaction product.

Abstract: A method for recovering 1,4-butanediol from a hydrolysate obtained by hydrolyzing diacetoxybutane, by (1) supplying the hydrolysate to a first distillation column, distilling off substantially all the amounts of water and acetic acid as the top stream from the first distillation column, and supplying a bottom liquid to a second distillation column, (2) distilling off diacetoxybutane and hydroxyacetoxybutane as the top or upper side stream from of the second distillation column, and circulating the distillates to a hydrolysis zone, while withdrawing crude 1,4-butanediol as a lower side stream in vapor phase from the second distillation column, (3) supplying the crude 1,4-butanediol and hydrogen gas to a hydrogenation reaction zone packed with a hydrogenation catalyst, and (4) supplying the hydrogenation reaction product to a third distillation column, distilling off low boiling point components and withdrawing 1,4-butanediol as the bottom or side stream from the third distillation column.

Abstract: Separation of ethylene glycol and diethylene glycol from dimethyl terephthalate is accomplished by distillation using methyl benzoate or the methyl ester of p-toluic acid as an azeotropic agent.

Abstract: Method for providing a proportioned gas flow of triisobutylaluminum from liquid triisobutylaluminum having isobutene admixed therein. The liquid is preheated sufficiently to evaporate the isobutene therefrom but leaving the triisobutylaluminum substantially in liquid phase. The vaporized isobutene is separated from the liquid triisobutylaluminum, and subsequently the triisobutylaluminum from which isobutene has been removed is evaporated. Preheating is conducted at a temperature of 30.degree.-40.degree. C. The evaporation of liquid triisobutylaluminum is conducted at a temperature of 40.degree.-60.degree. C.

Abstract: A process for recovering waste liquid from the distillation of fermented rice liquor. After filtration of the waste liquid, the residue can be recovered as dry feed, and the filtrate which contains about 4-5% crude protein, 1% starch and 92 wt. % water is first concentrated to lower the water content to about 70-80 wt. %. The filtrate is then dried with a spray dryer to produce nutritious dry feed while a suitable chelating agent such as magnesium hydroxide is used to prevent the clinging of the product on the wall of the dryer.

Abstract: Waste acetic acid, which is contaminated by nitrogen compounds and also by hardly hydrolyzable halogen compounds, is purified by adding a complex-forming metal or one of the compounds thereof and a basic compound. The resultant mixture is kept at a temperature between 25.degree. and 118.degree. C. over a period of time of 1 to 6 hours. Finally, purified acetic acid is removed from the mixture by distilling.

Abstract: To decrease the sulfur emissions of a sulfate cellulose mill, black liquor is heated before the last effect of the evaporation at a temperature higher than the cooking temperature of the sulfate cook and the sulfidity of white liquor is adjusted by adjusting the temperature and/or retention time of the heat treatment so that a predetermined amount of sulfur compounds are separated from the gaseous black liquor. Preferably, the sulfur containing gas is thereafter divided into different fractions and separately combusted.

Abstract: Mixtures containing alkylaromatrics chlorinated in the side chain are worked up by blowing them out with an inert gas before distillation at elevated temperature and carrying out the distillation in the presence of amines and/or chlorinated amines.

Abstract: A continuous evaporation process for drying water-wet waste solids and sludges, using a paraffin oil solvent, until the waste is dried to a near-zero wastewater product, without experiencing sticky solids. The invention involves (1) mixing the input solids or sludges with a paraffin oil solvent, (2) feeding the mixture into two or more stages of evaporation in parallel to evaporate some of the water present in the input solids or sludges and to extract some of the indigenous solvent-soluble compounds from the solids, (3) feeding the slurry from the parallel stages of evaporation to one or more final evaporation stages in series, and (4) feeding the slurry from the final stages of evaporation to a centrifuge or other device for separating most of the solvent from the solids.

Abstract: This invention provides a process for producing crystalline hydroxyacetaldehyde precipitated from a complex mixture of products provided by the pyrolysis of a carbohydrate-containing feedstock. The method includes distilling a first condensate under reduced pressure to give a second condensate which is enriched in hydroxyacetaldehyde; combining the second condensate with a solvent to give a homogeneous solution; precipitating hydroxyacetaldehyde from the solution; and separating the precipitated hydroxyacetaldehyde from the solution.Aqueous solutions of hydroxyacetaldehyde are useful for browning foodstuffs and for producing flavors by contacting the hydroxyacetaldehyde with ammonia or amines.In addition, hydroxyacetaldehyde may be used to make an artificial tanning product containing a suitable topical vehicle and an amount of hydroxyacetaldehyde suitable to impart a brown color to skin.

Abstract: Aqueous solutions which are contaminated by hydrogen sulfide, hydrogen cyanide, and ammonia are brought to a pH of about 3 or less after their formation and treated with an inert gas in a stripping column to remove the sulfide and cyanide. The pH of the solution is then increased to about 10 or more and the solution is again treated with an inert gas in a second stripping column to remove the ammonia.

Abstract: A method for the separation of Isoflurane from its admixture with other compounds produced in the chlorination of 2-difluoromethoxy-1,1,1-trifluoroethane including subjecting the mixture to distillation, distilling off the Isoflurane and effecting said distillation as an extractive distillation employing an extractive solvent which retards the vapor pressure of Isoflurane.

Abstract: A process for purifying an iodide-contaminated carboxylic acid and/or anhydride fraction obtained by liquid phase carbonylation using a carbonylation catalyst, an iodine-containing promoter and optional iodine-containing copromoter comprises vaporizing the fraction after it has been freed of catalyst, feedstock and promoter components to produce a vapor acid and/or anhydride fraction having reduced iodide contamination.

Abstract: A process for refining organic-solvent containing crude polyol fatty-acid polyester reaction product, including the steps of distilling the crude reaction product to substantially remove the organic solvent, and subsequently subjecting the distilled reaction product to a bleaching treatment. The process allows an economic use of bleaching agents while achieving good color and color stability of the refined product.

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.

Abstract: Method for the production of ultrapure sulfuric acid including distillation of sulfuric acid material for the removal of soluble impurities and insoluble and non-volatile particles of 10 microns to 0.2 micron or less in size. Reprocessing is also provided. Distillation takes place in a distillation chamber having walls which are provided with means within the chamber to provide smooth convective upward flow of distilling liquid and vapor proximate the walls and means for smooth convective downward flow substantially centrally of the distillation chamber. Redirection means and packing together with reflux means insure the washing of rising vapor and direct the condensing vapor substantially centrally of the distillation chamber. Ultrapure sulfuric acid is also provided having 5 or less particles per cubic centimeter of a size of 0.5 micron and larger and less than 10 ppb of any specific trace impurity such as cations.

Abstract: Disclosed herein is a process for removing chloroprene by subjecting chloroprene-containing 1,2-dichloroethane to heat treatment at a temperature in the range of from the boiling point (85.degree. C.) of 1,2-dichloroethane to the thermal cracking temperature (300.degree. C.) of 1,2-dichloroethane. In particular, the process can be suitably applied to a liquid distillate from a low-boiling material separation column in a step in which 1,2-dichloroethane used as a raw material for production of vinyl chloride is purified by using a fractionation column.

Abstract: The invention relates to a process for the isolation of vinyl acetate which involves not combining the bottom product of the recylced gas washings with the water-saturated vinyl acetate but rather introducing it to further multiple distillation columns from the gas mixture formed in the reaction of ethylene with acetic acid and oxygen over catalysts containing palladium or palladium compounds in the gas phase.

Abstract: A process for the purification of crude benzoic acid obtained by the catalytic oxidation of toluene in the liquid phase, which is contaminated with impurities including phthalic acid and benzylbenzoate, the process involves distilling the crude benzoic acid in a first distillation in the presence of an aliphatic amine or a mixture of aliphatic amines of the formulaHNR.sup.1 R.sup.2whereinR.sup.1 represents hydrogen or a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms andR.sup.2 represents a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms,and/or the salts of these amines, recovering from this distillation (a) a purified benzoic acid and (b) a benzylbenzoate containing residue, working up the residue by a second distillation and chlorinating the distillate resulting from this second distillation to give a benzoylchloride virtually free of benzonitrile.

Abstract: An apparatus and method for fluid distillation in general, and in particular, of water, adapted for consumer or home use, but capable of being made and operated so that it is suitable for separating solvents and solutes and other industrial use. The apparatus includes a housing having divider structure to form one or more compartments for receiving water to be distilled. The divider structure also presents a fluid passage for receiving water vapor which is formed when the upper portion of the water in the housing is boiled by a heater. An aerator is provided in the housing below the heater and in a location within the water compartment. The aerator operates to direct air under a slight pressure into the water so that air bubbles can be generated in the water. The air bubbles will rise and break the surface of the water as the upper part of the water is being boiled by the heater.

Abstract: The carbonylation of an alcohol to produce a carboxylic acid, especially methanol to produce acetic acid, in a low water reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions is improved by the addition of hydrogen in the feed gas to the low water reaction medium to obtain a reactor hydrogen partial pressure of at least about 4 psi. The presence of hydrogen in the reaction medium increases significantly the carbonylation reaction rate and reduces formation of byproduct carbon dioxide. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e.

Abstract: A process for recovering N-methylpyrrolidone contained in an N-methylpyrrolidone-containing liquid formed in the process for preparing a polyarylene thioether by the dehalogenosulfidation of a dihalogeno-aromatic compound and an alkali metal sulfide in the presence of N-methylpyrrolidone as the polymerization solvent, which comprises (a) subjecting the N-methylpyrrolidone-containing liquid to distillation to distill and recover the majority of contained N-methylpyrrolidone while recovering a distillation residue having such a flowability that flow transferring of the distillation residue is possible, and (b) supplying the distillation residue to an air-tight mixer for a highly-viscous fluid, which has a vent and is provided with a heater, to treat the distillation residue under the conditions of a temperature in the mixer of 190.degree. to 310.degree. C.

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.