Abstract: The present invention relates to a process for separating 2-butanol from tert-butanol/water by adding of tert-butanol such that the water concentration lowers to less than the limit concentration of the distillation boundary line connecting the two azeotropes TBA/water and SBA/water and is subsequently worked up by distillation.

Abstract: The invention relates to a process for separating 2-butanol from an industrial mixture which includes 2-butanol, tert-butanol and water by separating water from the industrial mixture by distillation to obtain a distillate, wherein the distillate has, in terms of the 2-butanol, tert-butanol and water in the industrial mixture, a proportion by mass of water, which at a pressure, is greater than the limit concentration of the distillation boundary line connecting an azeotrope of tert-butanol and water; and an azeotrope of 2-butanol and water; subsequently changing the pressure so that the mixture has, in terms of the 2-butanol, tert-butanol and water in the distillate, a proportion by mass of water which is less than the limit concentration of the distillation boundary line connecting the distillation boundary line connecting an azeotrope of tert-butanol and water; and an azeotrope of 2-butanol and water; and subsequently distilling the mixture at the same pressure into a stream comprising 2-butanol and a strea

Abstract: Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.

Abstract: The present invention provides new highly-efficient separation processes and systems for separating polymerization-grade ethylene and propylene from an initial effluent stream comprising ethane, ethylene, propylene, dimethyl ether, and one or more of propane, acetylene, methyl acetylene, propadiene, methane, hydrogen, carbon monoxide, carbon dioxide and C4+ components. In one embodiment, the initial effluent stream is provided from a methanol-to-olefin reaction system. It has been discovered that the best separation of these components is realized when DME is selectively removed in a first separation step, followed by separation of the remaining components in additional separation steps.

Abstract: Cyclic esters of hydroxy organic acids can be produced and recovered via azeotropic distillation. In certain embodiments cyclic esters, such as glycolide and lactide, can be produced from a fermentation broth or other feed stream that contains a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid using azeotropic distillation. The hydroxy organic acid of the feed stream or the hydroxy organic acid derived from the feed stream by decomposition is reacted to produce the cyclic ester. In other embodiments a crude composition of a cyclic ester of an organic ester can be purified using azeotropic distillation.

Abstract: The invention relates to a method for removing, by distillation, 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine, by a) removing the hexamethylenediamine from the mixture while obtaining a mixture (I) that has a hexamethylenediamine content of less than 1 wt. -%, b) removing completely or partially the 6-aminocapronitrile from mixture (I) while obtaining a mixture (II) whose content in substances that have a higher boiling point as 6-aminocapronitrile under distillation conditions and that cannot be formed by dimerization reactions when 6-aminocapronitrile is thermally treated is less than 1 wt. -%, and c) completely or partially removing from mixture (II) the hexamethylenediamine that might be present while obtaining a mixture (IV) whose hexamethylenediamine content is higher than that of mixture (II), and a mixture (V) whose hexamethylenediamine content is lower than that of mixture (II).

Abstract: The invention relates to a process for recovering and producing chemicals in a pulp production process where organic chemicals, such as formic acid and acetic acid, are used as cooking chemicals. The process of the invention is based on regeneration of cooking acids and formation of additional cooking acids and furfural by evaporating the cooking liquor and then separating acetic acid, formic acid, furfural and water. The separation is preferably carried out by distillation using the furfural formed in the process as a distilling aid in the distillation.

Abstract: A process produces ?-caprolactone by the oxidation of cyclohexanone by feeding a crude reaction mixture to a first distillation column; distilling off a first distillate containing low boiling components including unreacted cyclohexanone from the top of the first distillation column; recovering a first side-cut fraction containing unreacted cyclohexanone in a higher concentration than in the first distillate from an intermediate tray; recovering a first bottom liquid containing high boiling components including ?-caprolactone from the bottom; introducing the first side-cut fraction to a second distillation column; recovering a second bottom liquid containing unreacted cyclohexanone from the bottom of the second distillation column; recycling the second bottom liquid into the raw material cyclohexanone; introducing the first bottom liquid to a third distillation column to thereby yield a third distillate containing ?-caprolactone from the third distillation column.

Abstract: This invention relates to a continuous process for the preparation of silane by catalytic disproportionation of trichlorosilane in a reactive/distillative reaction zone having a catalyst bed of catalytically active solid.

Abstract: A process for distillative removal of ammonia from solutions (I) which include a lactam and ammonia comprises effecting said removal in a distillation apparatus (a) at an absolute pressure of less than 10 bar.

Abstract: A method for recovering hexamethylene diamine (HMD) from a mixture comprising HMD, 6-aminocapronitrile (ACN) tetrahydroazepine (THA), and adiponitrile (ADN) is disclosed. The method includes introducing the mixture into a first distillation column, separating as a group the HMD, ACN and at least a portion of the THA as distillate from the ADN. The first distillation column is operated at a temperature and pressure to minimize isomerization of the ADN into 2-cyanocyclopentylideneimine(CPI). The distillate of the first distillation column is introduced into a subsequent distillation column and the HMD is separated from the ACN and THA.

Abstract: There is provided an azeotropic mixture having 1,1,1,3,3-pentafluoropropane and hydrogen fluoride. Further, there is provided a process of separating/purifying R-245fa and/or HF from a mixture of R-245fa and HF wherein the mixture of 1,1,1,3,3-pentafluoropropane and hydrogen fluoride is subjected to a distillation step so that a distillate is obtained which has the azeotropic mixture of 1,1,1,3,3-pentafluoropropane and hydrogen fluoride, and a bottom product is obtained which has separated/purified 1,1,1,3,3-pentafluoropropane or hydrogen fluoride.

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

Abstract: The present invention relates to a process for separating secondary butanol (also referred to as 2-butanol or SBA below) from tert-butanol/water mixtures which are obtained in the dissociation of tert-butanol (TBA), in particular tert-butanol prepared from industrial C4-hydrocarbon mixtures, into isobutene and water.

Abstract: A method for recovering hexamethylene diamine (HMD) from a mixture comprising HMD, 6-aminocapronitrile (ACN) tetrahydroazepine (THA), and ADN comprising:

Abstract: This invention is an improved distillation sequence for the separation and purification of ethylene from a cracked gas. A hydrocarbon feed enters a C2 distributor column. The top of the C2 distributor column is thermally coupled to an ethylene distributor column, and the bottoms liquid of a C2 distributor column feeds a deethanizer column. The C2 distributor column utilizes a conventional reboiler. The top of the ethylene distributor is thermally coupled with a demethanizer column, and the bottoms liquid of the ethylene distributor feeds a C2 splitter column. The ethylene distributor column utilizes a conventional reboiler. The deethanizer and C2 splitter columns are also thermally coupled and operated at a substantially lower pressure than the C2 distributor column, the ethylene distributor column, and the demethanizer column. Alternatively, a hydrocarbon feed enters a deethanizer column.

Abstract: A process is disclosed for the purification, by distillation, of trimethylolpropane originating from the hydrogenation of 2,2-dimethylolbutanal, said process including the following steps: (a) reaction of n-butyraldehyde with formaldehyde in the presence of catalytic amounts of a tertiary amine, and hydrogenation of the resulting mixture to give a mixture containing trimethylolpropane; (b) separation of water, methanol, trialkylamine and/or trialkylammonium formate by distillation; (c) heating of the residue obtained in (b) under reduced pressure to a temperature at which TMP is volatile and compounds boiling above TMP are cleaved, in order to separate off, by distillation, TMP and compounds more volatile than TMP; (d) distillation of the distillate obtained in (c) in order to separate off the more volatile compounds and recover pure TMP; and (e) optional distillation of the TMP obtained in (d) in order to recover TMP with a low APHA color index.

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

Abstract: The invention relates to azeotropic and azeotrope-like mixtures of 1,1,1,3,3-pentafluorobutane (HFC-365) and hydrogen fluoride and a process for separating the azeotrope-like mixtures. The compositions of the invention are useful as an intermediate in the production of HFC-365. The latter is useful as a nontoxic, zero ozone depleting fluorocarbon useful as a solvent, blowing agent, refrigerant, cleaning agent and aerosol to propellant.

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

Abstract: A process for the recovery of substantially pure alkyl alkanoate, such as ethyl acetate, from an impure feedstock. The impure feedstock is contacted with a selective hydrogenation catalyst in the presence of hydrogen in a selective hydrogenation zone maintained under selective hydrogenation conditions effective for selective hydrogenation of impurities containing reactive carbonyl groups thereby to hydrogenate the impurities to the corresponding alcohols. After recovery from the selective hydrogenation zone of a selectively hydrogenated reaction product mixture including the alkyl alkanoate and the corresponding alcohols, this is distilled in one or more distillation zones so as to produce substantially pure alkyl alkanoate therefrom which is recovered.

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: 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: The invention relates to a process of separation of mixtures containing HFC-365mfc/HF azeotropic compositions by two distillations at different pressures, as well as to a process of synthesis of HFC-365mfc which integrates this process of separation and a recycling of certain fractions towards the hydrofluorination step.

Abstract: The present invention is a distillation system with individual fractionator tray temperature control, with the use of either a heating element or a cooling element, and in some preferred embodiments, the use of both a heating element and a cooling element in a plurality of fractionator trays. There is at least, and typically more than one distillation column having a plurality of fractionation trays, and having feed input, liquid removal, and vapor removal with the plurality of trays including at least one of a heating element and a cooling element. Controls are included for separate control of each of the heating element(s) and/or said cooling element(s). These controls may be regulated by a programmable microprocessor, and feedback from temperature sensors may be employed to provide discrete tray-by-tray temperature controls.

Abstract: A process for recovering processing liquids such as gas-treating liquids wherein a feed mixture containing the processing liquid, water, and optionally additional components that are more volatile than the processing liquid and components that are less volatile than the processing liquid, is initially heated in a first heating zone to a temperature sufficient to volatilize at least some of the water and a portion of the processing liquid without decomposing the processing liquid to produce a vapor stream containing volatilized water and processing liquid and a residuum containing the bulk of the processing liquid and less volatile component, the vapor stream being separated from the residuum and treated to produce recycle streams of water, purified processing liquid, and low and high boiling liquid fractions recovered from the purified processing liquid.

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

Abstract: Cyclic esters of hydroxy organic acids can be produced and recovered via azeotropic distillation. In certain embodiments cyclic esters, such as glycolide and lactide, can be produced from a fermentation broth or other feed stream that comprises a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid using azeotropic distillation. The hydroxy organic acid of the feed stream or the hydroxy organic acid derived from the feed stream by decomposition is reacted to produce the cyclic ester. In other embodiments a crude composition of a cyclic ester of an organic ester can be purified using azeotropic distillation.

Abstract: A process for the recovery and purification of cyclobutanone from a crude product mixture obtained from an oxidation product mixture resulting from the oxidation of cyclobutanol to cyclobutanone in the presence of water. The process provides for the recovery of cyclobutanone in a purity of at least 90 weight percent by a combination of distillation steps.

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

Abstract: A process for refining difluoromethane by removing hydrogen fluoride, which is contained in difluoromethane difficult to remove. The process involves distilling a mixture of difluoromethane with hydrogen fluoride where the mixture is in contact with sulfuric acid. The hydrogen fluoride remains in the liquid phase and the difluoromethane goes into the vapor phase.

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

Abstract: A method for preparing an organosilane functionalized in the 3 position includes reacting an allyl compound (H2C═CH—CH2X) with a silane (R2R3R4SiH) in a reaction column under a pressure between 1 bar and 25 bar, in the presence of a heterogeneous platinum catalyst. The silane reactant is present in the reaction column, and introduced into the reaction column, in a stoichiometric excess with respect to the allyl compound. The reaction column preferably includes a reaction zone, a first separation zone located above the reaction zone, and a second separation zone located below the reaction zone, wherein a first product exits the reaction zone and enters the first separation zone, and a second product exits the reaction zone and enters the second separation zone. Distillation occurs simultaneously with the reaction in the reaction chamber.

Abstract: An aqueous solution of free hydroxylamine is prepared by treating a hydroxylammonium salt with ammonia by the countercurrent method in a stripping column by a process in which hydroxylamine is liberated and at the same time the solution obtained is separated by distillation into an aqueous hydroxylamine solution and a salt fraction. The novel process can be carried out in a simple and gentle manner and on a large scale. The danger of decomposition is minimized owing to the low thermal load, the low concentration of hydroxylamine and the short residence time in the process.

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

Abstract: In a process for the preparation of methylglyoxal dimethyl acetal from methylglyoxal and methanol in the presence of an acidic ion exchanger, water is introduced in an amount sufficient to form an acidic reaction mixture in which the acetal product and water form an azeotropic mixture, with or without the retention of some methanol reactant. After subjecting a single phase acidic reaction mixture to an azeotropic distillation, it will separate into two distinct liquid phases with a simple recovery of the acetal product from the aqueous phase.

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

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

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

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

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

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

Abstract: 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 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: An apparatus and method for treating chemical production plant process condensate and low pressure purge gas such that a contaminant-rich stream is recoverable from the condensate and purge gas, wherein the contaminants are substantially removed from the condensate by steam stripping and subsequent rectification in a relatively low pressure stripping/rectification tower. The tower overhead is then condensed, and any non-condensed gases are subjected to water scrubbing, along with the low pressure purge gas to further recover contaminates from the non-condensed gas. A portion of the condensed overhead and scrubbing water containing contaminates is returned to the top of the rectification section of the tower as reflux and the balance being withdrawn as a concentrated stream for reuse in the plant. The apparatus may be used in conjunction with existing low pressure equipment, avoiding costly major modifications, and is particularly adapted to use in conjunction with ammonia and methanol plants.

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

Abstract: 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 separation of hydrogen fluoride (HF) and of difluoromethane (F32) by fractional distillation and/or condensation, in at least one stage, including in at least one stage obtaining a stream whose HF and F32 contents correspond.