Abstract: In distillation of a polymerizable compound such as (meth)acrylic acid or a liquid containing such a polymerizable compound with use of a distillation column equipped with a reboiler, (a) a vertical multi-tube reboiler whose outlet nozzle inside diameter (D1) is 0.2 to 1 time its reboiler shell inside diameter (D2) is used as the reboiler, (b) an outlet of an outlet nozzle of the reboiler to a gas-phase section of the distillation column is provided at a position such that a distance L from the top tubesheet of the reboiler to the lower end of the outlet of the outlet nozzle satisfies L=(0.4 to 3)×D1, and (c) a liquid level in the distillation column is maintained in a range such that a height H of the liquid level from the top tubesheet of the reboiler satisfies H=(0.1 to 0.8)×L.

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: 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: Less colored trans-1,3-dichloropropene and a process for producing it, are presented.

Abstract: A process for the distillative recovery of high purity monoethylene glycol from the hydrolysis, product of ethylene oxide by pressure dewatering, preferably in a battery, vacuum dewatering and subsequent purifying distillation, wherein during the vacuum dewatering an aqueous stream is withdrawn which contains-monoethylene glycol in a concentration below 1% by weight, preferably below 0.1% by weight, medium boilers and low boilers. The withdrawn aqueous stream is, optionally after further workup, removed from the system.

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 dividing-wall column having a dividing wall which is essentially disposed along the long direction of the column is proposed, which divides the column interior into a feed part, a take off part, an upper shared column part and a lower shared column part, with feed in whole or in part in the vaporous state of a mixture to be separated between the upper region of the feed part and the lower region of the feed part and/or side stream take off in whole or in part in the vaporous state between the upper region of the take off part and the lower region of the take off part, where if feed is in whole or in part in the vaporous state the cross-sectional area of the upper region of the feed part is increased by plane-parallel displacement of the dividing wall toward the upper region of the take off part, and/or if the side stream take off is in whole or in part in the vaporous state, the cross-sectional area of the lower region of the take off part is increased by displacement of the dividing wall toward the lower r

Abstract: The operation of the dividing wall section of a dividing wall column is controlled by a control apparatus comprising a ratio controller which divides the liquid flowing into the dividing wall section. The rate of return of overhead liquid to the column is set by monitoring the temperature in the top of the product dividing wall section and the sidecut product draw rate is set by monitoring a temperature in the bottom of the product dividing wall section.

Abstract: A process for the purification of a mixture of aromatic polyamines obtained by hydrogenation of the corresponding aromatic polynitro compounds, said mixture including the various isomers of the said amines as well as reaction by-products, including the steps of carrying out a distillation of the mixture in a distillation column, wherein a first stream, corresponding to a fraction or to all of the stream recovered at the bottom of the distillation column, is separated and is used in a chemical reaction and a second stream is separated corresponding (i) to a stream drawn off from the side in the gas phase, in the lower third of the said column, this stream representing at most 20% or more than 80% of the total volume (first and second stream); or (ii) to a fraction of the first stream, this fraction representing 2 to 50% of the volume of the first stream; in order to treat it subsequently.

Abstract: A process for the working up of a product stream from the epoxidation of olefins that contains olefin, olefin oxide, water-miscible organic solvent and water, by separating this product stream into an overhead product containing olefin, olefin oxide and organic solvent, and into a bottom product containing organic solvent and water, wherein the separation takes place in a pre-evaporator with less than 10 theoretical separation stages at a pressure of 1.5 to less than 3 bar, and 20 to 60% of the total amount of organic solvent introduced with the product stream is removed with the overhead product and the balance remains in the bottom product. A process for the epoxidation of olefins that includes this working up stage is also disclosed.

Abstract: A perforated tray without downcomer having only a small deviation between the opening ratio based on the diameter of a column and the actual opening ratio and a perforated tray column without downcomer formed by disposing such perforated trays without downcomer are provided. The perforated trays without downcomer are characterized by having a ratio of (A)/(B) in the range of 1.1-1.5, wherein A denotes the opening ratio found from the standard pitch between centers of holes and (B) denotes the opening ratio based on the diameter of a column.

Abstract: Undesired agents, which can reduce biocompatibility, can be selectively and substantially removed from implantable medical devices using methods of the present invention. Pressure and temperature of a supercritical fluid are adjusted to selectively remove one or more undesired agents from an implantable medical device perfused with the supercritical fluid. Treated implantable medical devices comprising at least about 75 wt % less of at least one undesired agent than the same device before undergoing a treatment are also disclosed.

Abstract: In a process for the fractional distillation of a liquid crude aldehyde mixture including straight-chain and branched aldehydes, the product mixture is fractionated in a first distillation column to give a product stream of branched aldehyde, a product stream of straight-chain aldehyde and a further product stream including straight-chain aldehyde and the high boiling constituents. The further product stream is then fractionated in a second distillation column whose packing volume is a factor of from 50 to 200 smaller than that of the first distillation column to give a product stream of straight-chain aldehyde and a high boiler product stream.

Abstract: A method for separating difluoromethane from a mixture of said difluoromethane and at least one impurity, said method comprising extractively distilling said mixture using dichloromethane as the extractive agent to recover a product stream of purified difluoromethane having a concentration of said impurity lower than that of said mixture.

Abstract: A process is disclosed for the purification, by distillation, of trimethylolpropane originating from the hydrogenation of 2,2-dimethylolbutanal, said process comprising the following steps:

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 formaldehyde-containing product is separated from a formalin solution containing formaldehyde, water and methanol by distilling the solution in the presence of a water entraining compound, especially methyl propionate or methyl methacrylate. The product contains substantially less water than in the solution and may be used, for example, in a further process which requires a source of formaldehyde containing a relatively low level of water, for example, the catalyzed reaction of methyl propionate with formaldehyde and methanol to produce methyl methacrylate.

Abstract: The invention relates to a process for preparing at least one aliphatic monoalcohol, generally in excess, and at least one olefin. The process is performed in a distillation and reaction device having a reaction section and a distillation-reaction section. The distillation-reaction section has a distillation zone with at least one means for circulation of the effluent from the reaction section to the distillation zone. Effluent from the reaction section is circulated to the distillation zone. The distillation-reaction section also has at least one distillation-reaction zone having at least one catalyst bed. The distillation-reaction zone is distinct from the distillation zone and provides at least partly the reflux of the distillation zone. The distillation-reaction section can also have at least one complementary reaction zone containing at least one catalyst bed.

Abstract: A process for separating a formaldehyde-containing product from a formalin solution comprising formaldehyde, water and methanol, wherein said formaldehyde-containing product contains substantially less water than said formalin solution, comprising distilling said formalin solution in the presence of a water entraining compound, especially methyl propionate or methyl methacrylate. The formaldehyde-containing product is suitable for use in a further process which requires a source of formaldehyde containing a relatively low level of water. One example of such a process is the reaction of methyl propionate with formaldehyde and methanol over a catalyst to produce methyl methacrylate.

Abstract: A purification tower for purifying liquid by contacting the liquid with gas, the purification tower including: (a) a shell; and (b) a plurality of baffles, each of which is fixed to an internal surface of the shell, (i) said each baffle having a flat upper surface and a plurality of openings are formed in each of the baffle so that the liquid and the gas pass through the openings; (ii) any adjacent pair of the baffles are arranged so that a bottom of the shell is covered by the pair of the baffles viewing in an longitudinal direction of the shell. The present invention thus configured can provide a process and an apparatus for the purification of even an organic compound containing a readily-blocking substances, which are capable of continuously purifying such an organic substance over the long time without discontinuing operations.

Abstract: The subject-matter of the present invention is process for the purification of a mixture of aromatic polyamines obtained by hydrogenation of the corresponding aromatic polynitro compounds, said mixture comprising the various isomers of the said amines as well as reaction by-products, comprising the steps of carrying out a distillation of the mixture in a distillation column, wherein a first stream, corresponding to a fraction or to all of the stream recovered at the bottom of the distillation column, is separated and is used in a chemical reaction and a second stream is separated corresponding(i) to a stream drawn off from the side in the gas phase, in the lower third of the said column, this stream representing at most 20% or more than 80% of the total volume (first and second stream); or (ii) to a fraction of the first stream, this fraction representing 2 to 50% of the volume of the first stream, in order to treat it subsequently.

Abstract: The invention relates to a process for separating dibutenes into an n-octene-containing fraction and a dimethylhexene-containing fraction. The fractions can be processed further separately to the corresponding C9 carboxylic acids and C9 alcohols (isononanols). Successor products of the C9 carboxylic acids include, for example, vinyl esters. Successor products of the C9 alcohols include plasticizers.

Abstract: Phenol is separated from a mixture containing hydroxyacetone, cumene, water and phenol, by fractionating the mixture in a process with a fractional distillation step and a phase separation step to provide a single phenol fraction containing less than 300 ppm of hydroxyacetone. In the work-up by distillation of cleavage product mixtures, the hydroxyacetone can be removed from the cleavage product mixture together with a phenol fraction from which the hydroxyacetone has to be removed. A process can be used for purifying cleavage product mixtures obtained in the cleavage of alkylaryl hydroperoxides such as cumene hydroperoxide. The process allows separation of phenol and acetone from mixtures obtained in the cleavage of cumene hydroperoxide.

Abstract: In a process for the preparation of (meth)acrylic acid from a mixture which contains (meth)acrylic acid and a solvent having a boiling point above the boiling point of (meth)acrylic acid by distillation of the mixture in a column which is connected to an evaporator and has a stripping section and a rectifying section, between which the mixture is fed in, and a side take-off for the (meth)acrylic acid, a polymeization inhibitor is fed into the column in the region of the top of the column and in the region of the side take-off, that amount of polymerization inhibitor which is introduced in the region of the top of the column being smaller than the amount introduced in the region of the side take-off.

Abstract: An organic isocyanate or mixture of isocyanates is treated with at least one high molecular weight ester of phosphoric acid corresponding to a specified formula to remove chlorine compounds. The isocyanates which are purified in this manner are useful for the production of coatings, polyurethane moldings and chemical intermediates.

Abstract: A method of distillation for separating a material which is solid at ambient temperature from a lower boiling and lower melting point material, and the apparatus.

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 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 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 high-fraction, terminally nonfunctional fluoropolyether lubricant topcoat is applied to a magnetic recording medium. The topcoat provides good stiction and wear properties at a low thickness.

Abstract: A method of separating methanol and dimethyl carbonate in a distillation column through extractive distillation. The extractive distillation is conducted in the presence of an extractive distillation agent which modifies the azeotropic behavior of the dimethyl carbonate/methanol mixture. A vapor side stream is removed from the distillation column.

Abstract: This invention resides in providing a method for the prevention of possible polymerization of the easily polymerizable substance during the purification thereof by a column provided with (a) at least one tray directly fixed to a support ring with a bolt and a nut and/or (b) at least one tray fixed to a support ring with a vertical clamp or a distillation column provided in the lower part thereof with a splash collision plate.

Abstract: Crude ammonia is separated into a low boiler fraction, a high boiler fraction and an intermediate-boiling pure fraction by continuous fractional distillation in a distillation apparatus configured either as a dividing wall column or as a system of thermally coupled distillation columns. In the process of the present invention, the low boiler fraction is taken off at the top of the distillation apparatus. The intermediate-boiling pure fraction is obtained at a side offtake which is preferably provided with droplet precipitators. In addition, the gas loading of the distillation column is restricted so that the operating pressure is in the range from 2 to 30 bar and the F factor does not exceed 2.0 Pa0.5.

Abstract: Cyclopentane and/or cyclopentene and, if desired, isopentane can be obtained by distillative separation from a pre-benzene fraction or a C5 fraction which has in each case being partially hydrogenated to remove acetylene compounds and diolefins, wherein a) in a first fractional distillation, low boilers are removed as first top product and, either b1) the first bottom product is fed to a second fractional distillation and there cyclopentene is taken off as second top product and cyclopentane and higher-boiling hydrocarbons are taken off as second bottom product and this second bottom product is separated into cyclopentene and higher boilers in a third fractional distillation, or b2) the first bottom product is subjected to a catalytic hydrogenation and subsequently, in a fractional distillation, separated into cyclopentane as top product and higher boilers as bottom product, or b3) the first bottom product is subjected to a fractional distillation to separate off the relatively high boilers as bottom prod

Abstract: A process for separating a fraction containing low and middle boilers from a mixture of low, middle and high boilers, which involves treating the mixture in a column with low-boiler vapor in the bottom, so that the middle-boiling component accumulates in the low-boiler vapor and can be obtained at the temperature level of the low-boiling component.

Abstract: A process for working up crude, liquid vinyl acetate feed containing acetic acid, water and ethyl acetate and optionally smaller amounts of other impurities by distillation, wherein there is introduced into the distillation column, above the feed point of the crude, liquid vinyl acetate, 0.1 to 5% by weight of water, based on the crude, liquid vinyl acetate feed, and 0.1 to 60% by weight of acetic acid, based on the crude, liquid vinyl acetate feed.

Abstract: Provided is a novel on-site system and method for providing ultra-high-purity nitric acid to a point of use. The system includes a source of nitric acid at a concentration greater than 68 wt %; a reflux distillation column having an inlet in communication with the nitric acid source for introducing nitric acid into the column, a reboiler, and a condensate outlet to provide a flow of nitric acid condensate from the column; a reservoir in communication with the condensate outlet for receiving the flow of nitric acid condensate; and piping for delivering nitric acid from the reservoir to a point of use. The system and method can be used as an on-site subsystem, in a semiconductor device fabrication facility for supplying the nitric acid condensate to points of use in the semiconductor device fabrication facility.

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: The invention relates to a distillation and reaction device having a reaction section and a distillation-reaction section. The distillation-reaction section has a distillation zone with at least one device for circulation of the effluent from the reaction section to the distillation zone. Effluent from the reaction section is circulated to the distillation zone. The distillation-reaction section also has at least one distillation-reaction zone having at least one catalyst bed. The distillation-reaction zone is distinct from the distillation zone and provides at least partly the reflux of the distillation zone. The distillation-reaction section can also have at least one complementary reaction zone containing at least one catalyst bed. The invention further relates to a process for preparing at least one aliphatic monoalcohol, generally in excess, and at least one olefin.

Abstract: A process is disclosed for removing chloropentafluoroethane (CFC-115) from a mixture comprising CFC-115, difluoromethane (HFC-32), pentafluoroethane (HFC-125), or from mixtures of these compounds, by azeotropic or extractive distillation.

Abstract: A process for recovering hexamethylenediamine (I) from a mixture (II) including(I) hexamethylenediamine,(III) hexamethyleneimine,(IV) a compound selected from 2-aminomethylcyclopentylamine and 1,2-diaminocyclohexane,(V) an imine,(VI) adiponitrile and 6-aminocapronitrileincludes distilling(a) a mixture (II) to obtain(a1) a low boiling fraction (III),(a2) a medium boiling fraction (VII) (I), (IV) and (V), and(a3) a high boiling fraction (V) and (VI),(b) a mixture (VII) to obtain(b1) an overhead product (IV), and(b2) a mixture (VIII) (I) and (V) as bottom product, and(c) a mixture (VIII) to obtain(c1) (I) as overhead product, and(c2) a bottom product (V).

Abstract: A process for distilling ethylene oxide out of a mixture including ethylene oxide in a column at an absolute pressure of from 2 to 10 bar and a temperature of 20 to 180.degree. C. by withdrawing pure ethylene oxide in the liquid or gaseous state overhead or via a sidestream in the rectifying section of the column includes effecting the distillation in a column having on its inside a plurality of successive zones of structured sheet-metal packing or dumped beds of packing elements, these zones being assigned one or more extinguishing systems on the outside of the column.

Abstract: Process for purification of aqueous solutions of hydrogen peroxide comprising the steps of adding one or more macroligands to said solution to form a mixture and forcing the mixture through an ultrafiltration membrane.

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: A system and process for purifying a 1,3-butadiene feedstock containing 1,3-butadiene and various impurities by first introducing the 1,3-butadiene feedstock stream to a separation column to produce an intermediate product stream containing 1,3-butadiene and residual impurities and then introducing the produced intermediate product stream through a condenser to a suitable dryer for removing residual impurities from the intermediate product stream and thereby forming a purified 1,3-butadiene stream. The separation column separates an overhead stream, containing 1,3-butadiene and impurities such as propadiene, water and oxygen, and a bottoms stream, containing impurities such as polymerization inhibitor, ethyl acetylene, 1,3-butadiene dimer, pentane and 1,2-butadiene, from the intermediate product stream which leaves the separation column in the form of a vapor side draw stream.

Abstract: An integrated deethanizer and ethylene fractionation column and process for separating a feed stream comprising ethylene, ethane and C.sub.3+ is disclosed. A single shell houses a refluxed upper portion and a lower portion of the column. A generally vertical wall partitions the lower portion of the column into a deethanizer section and an ethylene stripper section. The upper column portion is used as the absorption section of the ethylene fractionator. The feed is supplied to an intermediate stage in the deethanizer, and the deethanizer is operated at a lower pressure (and correspondingly lower temperature) matching that of the ethylene fractionation. The design allows the use of one slightly larger column in place of the two large columns previously used for separate deethanization and ethylene fractionation.

Abstract: Tray designs for use in a separation column for distilling or fractionating a feed stream are provided that incorporate co-current contact of the liquid and vapor streams and their subsequent separation on each tray. In one embodiment, located on the trays are a plurality of co-current vapor and liquid contacting sections including a volume of the tray in which vapors and liquid can be in co-current contact. Also located on the trays are a plurality of de-entrainment devices for separating entrained liquids from a vapor stream, the de-entrainment devices having an inner and an outer side, the inner side being adjacent to the co-current contacting sections.

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: A process for preparing high-purity cyclopropyl methyl ketone from compositions which contain cyclopropyl methyl ketone, 4,5-dihydro-2-methylfuran, addition products of 4,5-dihydro-2-methylfuran by a continuous rectification process in which at least a portion of the composition to be purified is introduced into a rectification apparatus via a side feed located above the bottom portion of the apparatus.

Abstract: The present invention comprises a dry cleaning system and method, in which dry cleaning machinery is used in conjunction with a specific solvent which is derived from an organic/inorganic hybrid (organo silicone). In this class of organo silicones is a group known as cyclic siloxanes. The cyclic siloxanes present the basis for material composition of the solvent chemistry which allows this dry cleaning system to be highly effective. The cyclic-siloxane-based solvent allows the system to result in an environmentally friendly process which is, also, more effective in cleaning fabrics and the like than any known prior system. The siloxane composition is employed in a dry cleaning machine to carry out the method of the invention.