Abstract: A desalination apparatus and method utilizing solar energy provided with a solar heat collector for heating a heating medium with solar energy, a heat exchanger cooperating with an evaporation can so as to subject the heating medium and raw water in the evaporation can to heat exchange and generate water vapor therein, a condenser cooperating with a raw water tank so as to receive the vapor from the evaporation can, cool the vapor by subjecting the vapor and raw water in the raw water tank to heat exchange and obtain distilled water.

Abstract: A method for the purification of crude acetonitrile comprising distilling the crude acetonitrile in a first fractional distillation column at below atmospheric pressure, withdrawing a first side draw fraction comprising acetonitrile, distilling the first side draw fraction in a second fractional distillation column at super atmospheric pressure, and withdrawing from the second distillation a second side draw fraction comprising purified acetonitrile.

Abstract: A (meth)acryloxy-bearing alkoxysilane is isolated and purified to a high purity by distilling a reaction solution containing the (meth)acryloxy-bearing alkoxysilane in a thin-layer distillation device at a temperature of 90-160° C. and a vacuum of 1-15 mmHg. The resulting alkoxysilane product does not give rise to the quality problem that the product will gradually whiten during storage owing to contact with air. The occurrence of self-polymerization of the alkoxysilane is restrained.

Abstract: A (meth)acryloxy-bearing alkoxysilane is isolated and purified to a high purity by distilling a reaction solution containing the (meth)acryloxy-bearing alkoxysilane in a thin-layer distillation device at a temperature of 90-160° C. and a vacuum of 1-15 mmHg. The resulting alkoxysilane product does not give rise to the quality problem that the product will gradually whiten during storage owing to contact with air. The occurrence of self-polymerization of the alkoxysilane is restrained.

Abstract: Disclosed is a process for the production and purification of dialkyl naphthalenedicarboxylate compounds wherein a crude naphthalenediacarboxylic acid is esterified with an alkanol such as methanol to produce a crude esterification product comprising dialkyl naphthalenedicarboxylate, starting materials and other compounds and the crude esterification product is purified by flash distillation to remove impurities which can cause fouling of conventional distillation equipment. A particularly useful diester is dimethyl 2,6-naphthalenedicarboxylate.

Abstract: Apparatus and process are disclosed for the distillation separation of styrene monomer from ethylbenzene utilizing a split feed to two distillation columns in conjunction with cascade reboiling utilizing thermal energy from the overhead of one column to supply heat to the second.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

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 method for removing a high boiling solvent from a pharmaceutical composition dissolved in the high boiling solvent comprising adding a low boiling co-solvent to the solution to form a mixture of the high boiling solvent and the low boiling co-solvent, and removing the solvent/co-solvent mixture under vacuum.

Abstract: A process and apparatus are provided for recovering diluent, unreacted monomer, and unreacted comonomer from a polymerization reactor effluent. The comonomer has a boiling point higher than the boiling point of the monomer and the diluent has a boiling point between the boiling points of the monomer and comonomer. The process and apparatus employ at least one flash tank, a first fractionation stage including a first column and operating at a first fractionation pressure, and a second fraction stage including a second column and operating at a higher second fractionation pressure. Comonomer is withdrawn from the first column as a fractionation product, and overhead vapor containing diluent and monomer is substantially condensed to yield a substantially condensed overhead stream. Liquid and vapor from the stream are separated in an accumulator.

Abstract: 5-Formylvaleric esters are prepared in a yield of not less than 90% by distillation of a formylvaleric ester mixture of 5-formylvaleric ester and either 3- or 4-formylvaleric ester or a mixture of 3- and 4-formylvaleric esters, where the ester radicals of the respective formylvaleric esters are identical, wherein the 3- or 4-formylvaleric ester or a mixture thereof is separated from the 5-formylvaleric ester in a distillation column at a pressure in the range from 2 to 100 mbar and a temperature of not above 150.degree. C. (measured as the temperature at the bottom of the column) and the esters used are the corresponding methyl or ethyl esters, where the purity of the 5-formylvaleric ester is not less than 98% and, as impurity, 4-formylvaleric ester is present in an amount of not more than 100 ppm.

Abstract: A process for recovering processing liquids such as gas-treating liquids wherein a feed mixture containing the processing liquid and components or impurities that are more volatile and less volatile than the processing liquid is initially heated in a first heating zone to a temperature sufficient to volatilize at least one of the more volatile components and a portion of the processing liquid, the temperature being maintained below the decomposition temperature of the processing liquid to produce a vapor stream containing the less volatile component and the vaporized portion of the processing liquid and a residuum containing the processing liquid, a reduced concentration of the more volatile components and the less volatile components, the vapor stream being separated from the residuum in a first separation zone, a portion of the residuum being passed through a second heating zone at a temperature below the decomposition temperature of the processing liquid to produce a first heated recycle stream, the heated

Abstract: In a process for the purification by distillation of chlorinated aromatic hydrocarbons originating from the chlorination of aromatic hydrocarbons in the presence of FeCl.sub.3, the crude reaction product is first partially degassed and then directly subjected to distillation in the presence of said FeCl.sub.3.

Abstract: A process for the separation of a mixture of a titanium tetrahalide, a reaction diluent of an intermediate boiling point and at least one of a titanium alkoxide, ester or complex thereof without the aid of a distinct separation solvent by subjecting the mixture to a first distillation step to separate the titanium tetrahalide as the lights component and subjecting the heavies product to a second distillation step to recover a portion of the reaction diluent as the lights component.

Abstract: A distillation plant includes a heat pump whose working fluid is compressed by a vapor jet compressor. A collection location for a liquid is arranged in the stripper part of a distillation column of the plant. At least a portion of the collected liquid is provided in the vaporized form as strip vapor. Connections lead from the collection location to a first vaporizer and to a second vaporizer. The liquid can be vaporized in these vaporizers at an elevated and at a reduced pressure respectively. The vapor jet compressor is connected to the two vaporizers and to the column in such a manner that the vapor from the second vaporizer can be compressed under a driving jet action of the vapor from the first vaporizer and used in the column as strip vapor. A pump is arranged in the connection to the first vaporizer and at least one restrictor member is contained in the connection to the second vaporizer.

Abstract: A method for purifying acetic acid containing at least one component selected from the group consisting of unsaturated compounds and carbonyl compounds as an impurity involves the step of purifying the acetic acid with a distillation column having at least 30 plates by operating the distillation column at a pressure ranging from 40 to 760 mmHg and a reflux ratio of at least 4, and yields a high-quality acetic acid which rates high in the potassium permanganate test without needing of the addition of any chemical to the acetic acid to be purified and a large amount of energy, and is economical.

Abstract: An improved process for the preparation of caprolactam by heating 6-aminocapronitrile in the presence of a heterogenous catalyst and water under superatmospheric pressure without rapid deactivation of the catalysts used. The process further includes the addition of a low or high boiling alcohol in the heating phase, after which the products are obtained by distillation. The process further includes a method of working up the top and bottom products of the reactors to achieve higher yields.

Abstract: A process for preparing and/or extracting samples by heating them together with a solvent in a container under pressure, using a Soxhlet apparatus. The samples are dried by heating in a container; and the resultant vapors are drawn off to generate a vacuum in the container.

Abstract: A large and economical type of multi-stack vertical tube evaporator (MS-VTE) having units of multiple stacks of vertical tube bundles or stages mounted in a single vessel, and having its liquid feed pumped to the uppermost VTE bundle stack or stage and having the feed then cascading downward through the lower bundle stacks in series flow, and wherein all the tube bundles are heated with the same waste steam of no or low $-value, e. g. with turbine reject steam in parallel flow under vacuum into the steam-sides of all tube bundles in the unit through a common steam conduit; and wherein the feed liquid is progressively evaporated from stage to stage or stack to stack and the vapors produced in the tubes of each bundle during the partial evaporation of the feed are separated between the stacks and condensed by parallel flow into one or more condensers.

Abstract: A method of recovering ethylene sulfide from a hydrous stock solution (solution) containing ethylene sulfide, toluene (hydrophobic organic compound) having a higher boiling point than ethylene sulfide, and a compound having a higher boiling point than toluene, by distilling the stock solution continuously using a continuous fractionating tower 2, a fractionating tower 4, and a rectifying tower 5. Ethylene sulfide is distilled out with toluene and water from the continuous fractionating tower 2, and the distillate is allowed to separate into an oil layer and a water layer in a separating tank 3. The oil layer is distilled continuously by the fractionating tower 4 without being subjected to a reflux operation to distill out water with a part of ethylene sulfide. The bottom product from the fractionating tower 4 is rectified by the rectifying tower 5 to recover ethylene sulfide.

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: 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: Methyl tertiary butyl ether is prepared from contaminated TBA by reactively distilling the contaminated TBA in a reactive distillation column to provide a lower boiling isobutylene fraction and a higher boiling aqueous TBA fraction, by distilling the higher boiling aqueous TBA fraction to provide a lower boiling TBA fraction, by charging the lower boiling isobutylene fraction, the lower boiling tertiary butyl alcohol fraction and methanol to an etherification reactor to form an etherification reaction product, by distilling the etherification reaction product to provide a lower boiling fraction containing isobutylene, methanol and methyl tertiary butyl ether by charging the lower boiling fraction to a finishing reactor to react the isobutylene and methanol contained therein to from additional MTBE and by recovering MTBE from the etherification reaction product and the isobutylene conversion product.

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: A monotube or multitube 2 is coupled to a body shell 1 via tube plates 3a and 3b at both ends, so that a tube interior 4 and a tube exterior 5 of the monotube or multitube 2 are isolated from each other. A difference is made in operating pressure between the tube interior 4 and the tube exterior 5, so that one of the tube interior 4 and the tube exterior 5 is used as a lower-pressure column and the other is used as a higher-pressure column. A wall of the tube is used as a heat transfer surface, so that heat is transferred from the higher pressure side (higher temperature side) to the lower pressure side (lower temperature side).

Abstract: The present invention discloses a polymerization system having at least two reaction chambers wherein vacuum is used to remove vapors therefrom comprising a single vacuum system for supplying vacuum in increasing amounts to successive reaction chambers. Also disclosed is a polymerization process having at least first and second reaction chambers in which the pressure is decreased successively from said first chamber to a final chamber.

Abstract: A process for the recovery of a carbonylation product from a liquid reaction composition of an iridium-catalysed carbonylation reaction of a carbonylatable reactant includes subjecting the composition to a vaporization with or without the addition of heat to produce a vapor-fraction and a liquid fraction, the vapor fraction includes carbonylation product and the liquid fraction has a water concentration of at least 0.5% by weight to stabilise the iridium catalyst.

Abstract: In a method for the extraction treatment of a sample (19) with a solvent which is liquid at normal ambient temperature and normal pressure, in which the solvent is introduced into a preferably heatable sample chamber (12a) and there brought into contact with the sample (19), in which the solvent vapour arising in the sample chamber (12a,26) is drawn off out of the sample chamber in such a manner that an under-pressure arises in the sample chamber and a further part of the liquid solvent passes into the vapour phase, and in which the drawn off solvent vapour is cooled outside the sample chamber (12a,26) and thereby, for the purpose of recovery of pure solvent, is at least partially passed back into the liquid phase, the drawn-off solvent vapour is additionally subjected to over-pressure.

Abstract: An improved urea recovery process is presented. In the improved process, multiple vacuum rated surface condensers used to condense water vapor evolved during urea vacuum evaporation/concentration are replaced by a direct contact cooler/absorber to obtain substantial capital and utility cost savings. Improved heat exchange efficiency of the present process significantly reduces cooling water usage in comparison to the surface condensers.

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: 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: The invention relates to a process for the treatment of contaminated ethylene glycol resulting during a polycondensation process for the production of polyester. In the course of this polycondensation process contaminated ethylene glycol is continuously predistilled, subjected as a distillation residue to secondary distillation, condensed and then returned to the polycondensation process as decontaminated ethylene glycol, so that an in-line recovery is achieved, which makes superfluous an external distillation installation for the treatment of contaminated ethylene glycol.

Abstract: A method for the separation and purification in a single pass of a heat or oxygen-sensitive liquid feed, such as a plant derived liquid feed mixture of fatty acids, tocopherol compounds and sterols, into a low boiling point purified fraction of Vitamin E tocopherol compounds and a high boiling point concentrate fraction of triglycerides, which method can be maintained in the presence of an inert gas to provide reduced degradation and increased purity of the Vitamin E fraction.

Abstract: An improved process for azeotropic distillation of chloral to anhydrous chloral containing as little as 0.1% water. An azeotropic mixture is used which contains chloral in at least a 1.4:1 ratio with the concentration (% of weight) of a azeotropic agent (preferably ethylene dichloride). The feed stream may contain other components, but will contain at least 60% chloral and less than 40% water. Preferably, the feed stream is substantially free of components other than choral and water. Water is removed from the overhead product of the azeotropic and EDC separation distillations periodically or continuously throughout the process. The azeotropic agent is preferably separated from the anhydrous chloral product. This separation may be performed in the azeotropic distillation column or in a separate distillation column.

Abstract: For the regeneration of a liquid desiccant, a stripping agent is used which is liquid at ambient temperature and pressure, and forms a heteroazeotrope with water, along with the following steps: (a) distillation of the water-laden liquid desiccant to form vapor and partially regenerated liquid desiccant; (b) reboil partially regenerated liquid desiccant; (c) stripping of partially regenerated liquid desiccant during (a) and (b), using vaporized stripping agent; (d) a condensing of vapor the exiting the distillation, the condensation producing two liquid phases, one mainly water and the other mainly stripping agent; (e) heating the stripping agent-rich liquid phase exiting step (d) to generate a vapor phase which is richer in water than said liquid phase and a water-depleted liquid phase; and (f) returning the vaporized liquid phase exiting step (e) to step (c).

Abstract: The present invention provides a method for removing an organic compound in water at a high efficiency by separating an organic compound, particularly such an organic chlorine compound as 1,2-dichloroethane, carbon tetrachloride and chloroform dissolved in water or forming two liquid phases with water from a water phase, by the steps of:(i) charging water containing an organic compound into a first distillation column for conducting distillation or steam distillation to take the organic compound and water out of the top of the first distillation column and to obtain a bottom liquor containing the organic compound at a lower content from the bottom of the first distillation column, and(ii) charging the bottom liquor of the first distillation column into a second distillation column operated at a pressure lower than that in the first distillation column for conducting distillation, preferably flashing under reduced pressure, to take a gas distillate containing a large amount of the organic compound out of the t

Abstract: A distillation method for the purification of crude propylene oxide containing contaminating quantities of water and methanol by partially purifying the crude propylene oxide in a plural stage distillation zone to provide a vaporized overhead distillate propylene oxide fraction containing a minor contaminating amount of vaporized water, andpassing the propylene oxide vapor fraction through a drying chamber containing a porous hygroscopic solid absorbent to selectively absorb water vapor onto the absorbent,and liquefying and recovering the thus-dehydrated purified propylene oxide.

Abstract: A novel process for the recovery of tocopherols and sterols from natural, especially vegetable, sources. This process is especially a process for the separation of tocopherols and sterols from deodorizer sludges by distillation of these deodorizer sludges, in that prior to the distillation the sterols present in the deodorizer sludge are esterified with the fatty acids which are also present, the resulting mixture is distilled to obtain residual fatty acids and subsequently to obtain tocopherols, whereby the sterol esters formed in the esterification remain in the residue of this distillation, and then the tocopherols are isolated from the distillate and the sterols, after cleavage of their esters, are isolated from the distillation residue.

Abstract: Reprocessing mixtures which contain organic solvents and constituents of low volatility and may contain water: includes introducing the mixture into a concentration apparatus of a solvent recovery system, concentrating the mixture in the concentration apparatus by evaporating off a portion of a readily volatile fraction and feeding this readily volatile fraction to a separation column. A portion of the concentrated mixture from the concentration apparatus is conducted away into a separation apparatus where the constituents of low volatility are separated off from the concentrated mixture and ejected from the solvent recovery system. The concentrated mixture is conducted away, freed from the constituents of low volatility, from the separation apparatus.

Abstract: A process for the purification of caprolactam from crude caprolactam by distilling the crude caprolactam in the presence of an anorganic or organic acid.

Abstract: A process for preparing diacetoxybutene, including:reacting butadiene, acetic acid and oxygen in the presence of a palladium-based catalyst;feeding continuously the resulting reaction product into a first distillation tower;feeding continuously a withdrawn bottoms withdrawn from the first distillation tower into a second distillation tower;withdrawing bottoms containing high boiling point materials from the bottom of the second distillation tower, so that the content of the high boiling point materials in the bottoms of the second distillation tower is not more than 20 wt %;feeding continuously the withdrawn bottoms into a thin-film evaporator whose internal pressure is kept lower than the bottom pressure of the second distillation tower to carry out evaporation treatment; andrecycling the evaporated materials mainly containing diacetoxybutene into the second distillation tower.

Abstract: A process for the purification of organic polyisocyanates by mixing of the polyisocyanate with from 0.001 to 1% by weight of compounds containing trimethylsilyl groups at temperatures of from 20.degree. to 150.degree. C. The resultant mixture of organic polyisocyanates and compounds containing trimethylsilyl groups is optionally treated by degasification or distillation. These purified polyisocyanates are suitable for the production of polyurethane plastics, and in particular, polyurethane foams.

Abstract: Contaminants are removed from impure propylene oxide by fractionating in a first column to remove overhead essentially all of the pentenes and pentanes and most of the oxygen-containing impurities to provide a partially purified first propylene oxide bottoms fraction, extractively distilling the first bottoms fraction in a second extractive column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a second overhead fraction comprising propylene oxide, hexenes, hexanes, water, residual quantities of pentenes and pentanes and oxygen-containing impurities, extractively distilling the second overhead fraction in a third column using a C.sub.6 to C.sub.10 alkane hydrocarbon extractive distillation agent to form a third bottoms fraction comprising the extractive distillation agent, propylene oxide, hexenes, hexanes, residual quantities of pentenes and pentanes and water, and extractively distilling said third bottoms fraction in a fourth column using a C.sub.6 to C.sub.

Abstract: A process for the production of pure distilled isocyanates in which the corresponding amine is reacted with phosgene in a suitable solvent and working up of the isocyanate containing solution obtained by multistage distillation into pure isocyanate, pure solvent and a residue. The residue is then charged to a vessel containing at least one hydrocarbon having a high boiling point. The contents of this vessel are then heated with stirring to distill off any free isocyanate present. The remaining residue is a solid which may be disposed of readily.

Abstract: A process and system for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled.

Abstract: A process for the purification and concentration of sulfuric acid contained with nitric acid by-products and organic components pursuant to the mixed acid nitration of aromatics.

Abstract: 2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.

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: High purity isopropyl acetate and ethanol are recovered from a process stream containing isopropyl acetate, ethanol and water by a multiple step process including extracting substantially all of the ethanol from the stream using water as a solvent, stripping the extract stream to remove substantially all of the remaining isopropyl acetate as an overhead recycle stream, which is combined with the fresh feed stream prior to the extraction step, fractionating the ethanol-rich stripping column bottoms stream to produce a ethanol-water azeotropic overhead stream and using a portion of the fractionating column bottoms stream as the solvent for the extraction step.