Abstract: Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II where R is hydrogen or a C1-C20-alkyl group, wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80° C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.

Abstract: Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II where R is hydrogen or a C1-C20-alkyl group, wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80° C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.

Abstract: A process is proposed for the treatment of a recycling stream (1) from a plant for the production of polyarylene ether sulfones via polycondensation of aromatic bishalogen compounds and of aromatic bisphenols or their salts in the presence of at least one alkali metal carbonate or ammonium carbonate or alkali metal hydrogencarbonate or ammonium hydrogencarbonate in an N-alkyl-2-pyrrolidone as solvent, comprising from 60 to 90% by weight of water, from 10 to 40% by weight of N-alkyl-2-pyrrolidone and, as contaminant detrimental to specification, up to 5000 ppm by weight of the alkylsuccinimide corresponding to the N-alkyl-2-pyrrolidone and, alongside this, up to 1000 ppm by weight of other substances with higher boiling point than N-alkyl-2-pyrrolidone, in particular inorganic salts, based in each case on the total weight of the recycling stream (1), where the entirety of the components gives 100% by weight, giving a pure N-alkyl-2-pyrrolidone stream (2) which can be returned to the plant for the productio

Abstract: Process for purifying N-alkylpyrrolidones which due to a previous use comprise at least one of the impurities of the formula I or II where R is hydrogen or a C1-C20-alkyl group, wherein a basic compound is added to the N-alkylpyrrolidone to be purified and the temperature of the mixture is at least 80° C. not more than 20 minutes after addition of the basic compound and N-alkylpyrrolidone is distilled off from the mixture obtained.

Abstract: The present invention provides a method for producing of ultra-clean and high-purity N-methyl pyrrolidone through using industrial grade N-methyl pyrrolidone as raw material. After the pretreatment, sorption and dehydration with 4A molecular sieve, twice membrane filtrations are carried out through using ?-cyclodextrin composite membrane for the first and 18-crown-6 composite membrane for the second. The filtrate is rectified under vacuum and filtered through using complexant composite microporous membrane to obtain the product. The ultra-clean and high-purity N-methyl pyrrolidone, produced by the method provided by the present invention, is up to the SEMI C8 standard. And the purity of the product is over 99.8%, the moisture content is less than 0.03%, and the content of single metal ion is less than 1 ppb. Comparing to the prior art, the present invention has the advantage such as the stable quality of the product, simple operation, and is suitable for industrial continuous production.

Abstract: The invention relates to a method for purifying N-alkyl-substituted pyrrolidones which have contaminants with a higher degree of oxidation, by hydrogenation of the same and distillation.

Abstract: The invention relates to a process for the treatment of an aqueous mixture comprising a dipolar aprotic compound, comprising: a) an adsorption step, in which the aqueous mixture is brought into contact with a porous adsorbent, whereby the porous adsorbent is chosen such that the dipolar aprotic compound adsorbs to it more readily than water; b) a desorption step, in which the porous adsorbent is brought into contact with a desorbing agent, whereby a recovery solution is formed comprising the desorbing agent and the dipolar aprotic compound.

Abstract: The present invention provides a method for producing of ultra-clean and high-purity N-methyl pyrrolidone through using industrial grade N-methyl pyrrolidone as raw material. After the pretreatment, sorption and dehydration with 4A molecular sieve, twice membrane filtrations are carried out through using ?-cyclodextrin composite membrane for the first and 18-crown-6 composite membrane for the second. The filtrate is rectified under vacuum and filtered through using complexant composite microporous membrane to obtain the product. The ultra-clean and high-purity N-methyl pyrrolidone, produced by the method provided by the present invention, is up to the SEMI C8 standard. And the purity of the product is over 99.8%, the moisture content is less than 0.03%, and the content of single metal ion is less than 1 ppb. Comparing to the prior art, the present invention has the advantage such as the stable quality of the product, simple operation, and is suitable for industrial continuous production.

Abstract: A process for removing by-products from N-vinylamide-rich product mixtures (crude N-vinylamide), which comprises performing an extraction of the crude N-vinylamide with an organic solvent as the extractant.

Abstract: A method for producing N-vinyl-2-pyrrolidone by crystallization including: controlling a water content in a feed N-vinyl-2-pyrrolidone solution at an inlet of a crystallizer so as to be not lower than 0.7% by weight and not higher than 10% by weight based on the total weight of the N-vinyl-2-pyrrolidone solution; and supplying the feed N-vinyl-2-pyrrolidone solution to a crystallization process.

Abstract: A process for purifying removal of acrylic acid, methacrylic acid, N-vinylpyrrolidone or p-xylene crystals from their suspension in mother liquor by means of a wash column with forced transport, whose shell of the process chamber is a metal wall, the wash column additionally being enveloped by a thermal insulation material having a water vapor barrier and a specific heat flow of >0.1 W/m2 and <10 W/m2 flowing into the process chamber through the metal wall of the wash column.

Abstract: A process for continuously removing a target product X in the form of fine crystals from a liquid phase P comprising the target product X and constituents other than the target product X by cooling suspension crystallization in an indirect heat transferer, in which the crystal suspension formed is conducted out of the heat transferer first into a mixed buffer tank and, from there, fed to an apparatus for separating the crystal suspension into crystals and liquid phase, and wherein external measures dissipade the oversaturation of the crystal suspension fed to the buffer vessel with target product X.

Abstract: High-purity NVP can be produced by comprising at least two crystallization processes and supplying the mother liquor from the first crystallization process to the second crystallization process. Further, high-purity NVP can be obtained continuously and stably without plugging caused by depositing of crystals on the heat transfer surface of a crystallizer by controlling the water content in a feed NVP solution at the inlet of the crystallizer so as to be not lower than 0.7% by weight and not higher than 10% by weight.

Abstract: A process for continuously removing a target product X in the form of fine crystals from a liquid phase P comprising the target product X and constituents other than the target product X by cooling suspension crystallization in an indirect heat transferee, in which the crystal suspension formed is conducted out of the heat transferer first into a mixed buffer tank and, from there, fed to an apparatus for separating the crystal suspension into crystals and liquid phase, and wherein external measures dissipade the oversaturation of the crystal suspension fed to the buffer vessel with target product X.

Abstract: The invention relates to a process for the treatment of an aqueous mixture comprising a dipolar aprotic compound, comprising: a) an adsorption step, in which the aqueous mixture is brought into contact with a porous adsorbent, whereby the porous adsorbent is chosen such that the dipolar aprotic compound adsorbs to it more readily than water; b) a desorption step, in which the porous adsorbent is brought into contact with a desorbing agent, whereby a recovery solution is formed comprising the desorbing agent and the dipolar aprotic compound.

Abstract: A process for purifying removal of acrylic acid, methacrylic acid, N-vinylpyrrolidone or p-xylene crystals from their suspension in mother liquor by means of a wash column with forced transport, whose shell of the process chamber is a metal wall, the wash column additionally being enveloped by a thermal insulation material having a water vapor barrier and a specific heat flow of >0.1 W/m2 and <10 W/m2 flowing into the process chamber through the metal wall of the wash column.

Abstract: A method for purifying N-vinyl-2-pyrrolidone (NVP) is disclosed. The method comprises crystallizing NVP in the presence of added water to produce purified NVP crystals and a mother liquor, and then isolating the purified crystals. In a preferred method, 0.5 to 4 wt. % of water based on the amount of NVP to be purified is added, and the NVP crystals are washed with additional pure NVP, preferably NVP crystal melt, to give crystals having a purity greater than 99.99%. The method provides a fast, effective way to generate and isolate pure NVP in a single-stage crystallization.

Abstract: The invention relates to a method for the production of a purified melt of a monomer melt obtained by condensation, absorption or extraction in a crystallizer, wherein the inlet to the crystallizer is subjected to a mechanical solid/liquid separation operation.

Abstract: The invention provides a method for producing purified N-vinyl-2-pyrrolidone free of odorous components. The method is composed of distilling with a distillation column a liquid, which is formed by adding to an odorous components-containing liquid having a N-vinyl-2-pyrrolidone purity of not lower than 90 wt %, a compound having boiling point lower than that of N-vinyl-2-pyrrolidone, and whereby removing the odorous components together with said low-temperature boiling compound as the distillate.

Abstract: A process for working up residues from the preparation of pyrrolidone and/or N-vinylpyrrolidone comprises subjecting the residues to a thermolysis.

Abstract: The invention relates to a method for the production of a purified melt of a monomer melt obtained by condensation, absorption or extraction in a crystallizer, wherein the inlet to the crystallizer is subjected to a mechanical solid/liquid separation operation.

Abstract: The invention relates to a method for purifying a raw melt of at least one monomer by crystallization, wherein suspension crystallization is initially used and the resulting remaining melt or the suspension crystals that have been molten once again and separated are subjected to a mechanical separation operation before undergoing subsequent purification by crystallization.

Abstract: A method for obtaining high purity N-(2-hydroxyethyl)-2-pyrrolidone satisfactory for use as an intermediate material for N-vinyl-2-pyrrolidone from a reaction liquid formed of a reaction between y-butyrolactone and 2-aminoethanol, i.e., a liquid containing N-(2-hydroxyethyl)-2-pyrrolidone, compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone and compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone. The method is characterized by distilling said reaction liquid using a distillation column, whereby obtaining a liquid containing the compounds having the lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone and N-(2-hydroxyethyl)-2-pyrrolidone as a distillate liquid from the column top and a liquid containing compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone as a bottom liquid.

Abstract: The invention describes a process for the isolation of pure N-vinylpyrrolidone from N-vinylpyrrolidone-containing crude products, comprising a single-stage or multistage crystallization process, which comprises passing the mother liquor from the first crystallization stage either to a distillative and/or extractive purification, or returning it to an N-vinylpyrrolidone-containing product stream of the preparation process.

Abstract: The invention provides a method for producing purified N-vinyl-2-pyrrolidone free of odorous components. The method comprises distilling with a distillation column a liquid, which is formed by adding to an odorous components-containing liquid having a N-vinyl-2-pyrrolidone purity of not lower than 90 wt %, a compound having boiling point lower than that of N-vinyl-2-pyrrolidone, and whereby removing the odorous components together with said low-temperature boiling compound as the distillate.

Abstract: The invention describes a process for the isolation of pure N-vinylpyrrolidone from N-vinylpyrrolidone-containing crude products, comprising a single-stage or multistage crystallization process, which comprises passing the mother liquor from the first crystallization stage either to a distillative and/or extractive purification, or returning it to an N-vinylpyrrolidone-containing product stream of the preparation process.

Abstract: A process for working up residues from the preparation of pyrrolidone and/or N-vinylpyrrolidone comprises subjecting the residues to a thermolysis.

Abstract: A process for separating hydrogen chloride from a mixture including an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride by distilling the mixture including an N-(C1-C18)-alkyl-2-pyrrolidone and hydrogen chloride at from 100 to 220° C. and from 50 to 850 hPa in the presence of water in a distillation column, condensing the water as water-hydrogen chloride azeotrope at the top by cooling, returning the water-hydrogen chloride azeotrope to the distillation column, separating off gaseous hydrogen chloride at the top and taking off the N-(C1-C18)-alkyl-2-pyrrolidone from the bottom.

Abstract: The present invention related to safe botanical drug for treatment and prevention of Alzheimer's disease. Specifically, this invention proves a safe botanical drug, Huperzine (HUE) and Clausenamide (CLE) and their preparation. HUE has the following pharmaceutical functions: inhibiting acetylcholinesterase (CAT), increasing memory, decreasing Alzheimer amyloid protein, increasing RNA and protein synthesis of brain, increasing calcium in brain, decreasing superoxide anion. CLE has the following pharmaceutical functions: increasing memory, decreasing Alzheimer amyloid protein, increasing RNA and protein synthesis of brain, increasing calcium in brain, decreasing superoxide anion, increasing long-term potentiation and increasing dopanmine (DA). It is important that HUE combined with CLE have stronger function as mentioned above.

Abstract: A process for recovering N-vinyl-2-pyrrolidone is provided which allows to recover N-vinyl-2-pyrrolidone efficiently and steadily and in high purity by continuous distillation from a mixed liquid containing N-vinyl-2-pyrrolidone, N-(2-hydroxyethyl)-2-pyrrolidone, compounds having a higher boiling point than N-vinyl-2-pyrrolidone and water. The process includes continuously distilling the mixed liquid using a distilling column, controlling the temperature of the bottom liquid of the distilling column at 180° C. or less.

Abstract: This invention relates to a composition containing (a) a component selected from the group of a mono- or poly- vinyl substituted mono- or poly-ether, a mono- or poly- vinyl substituted lactam, or a mixture thereof contained in an acidic medium and (b) an aliphatic, primary or secondary mono- or poly-amine at a concentration sufficient to adjust the pH of the composition above

Abstract: A process for reducing the amine content of amine-contaminated N-substituted lactams comprises treating the contaminated N-substituted lactams with an acid macroporous cation exchanger.

Abstract: A process is provided for moving at least one contaminant selected from the group consisting of phenol thiophenol, and phenyl disulfide from contaminated NMP by reacting at least one monohalogenated aromatic compound and a base with the contaminate NMP.

Abstract: A process for producing an N-vinyllactam by reacting a lactam with acetylene in the presence of a particular catalyst (an alkali metal alcoholate between an alicyclic alcohol and an alkali metal) in a nonaqueous system at an acetylene partial pressure of 0 to 10 kg/cm.sup.2 .multidot.G.In the above process, the vinylation of lactam with acetylene is conducted at a low acetylene partial pressure in one step while the formation of by-product is kept minimum, whereby a high conversion and a high selectivity of lactam can be achieved.

Abstract: This invention relates to a method for improving the properties of lactones and substituted lactams by subjecting the post-manufactured lactones and substituted lactams to an ion exchange resin. Specifically, this invention relates to a method for reducing the cationic impurities concentrations, reducing the amine concentration, and reducing the pH of post manufactured lactams.

Abstract: In a process for purifying N-vinylpyrrolidone by crystallization in a crystallizer, those surfaces of the crystallizer from which crystals grow during the crystallization are covered with an N-vinylpyrrolidone seed layer before the crystallization.

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: Chemical impurities contained in N-vinylpyrrolid-2-one are bound by a process in which the anhydride of an organic carboxylic acid is added to the crude N-vinylpyrrolid-2-one.

Abstract: A method for recovering a liquid diluent having a low salt content from an organic/aqueous mixture which contains significant quantities of the diluent, an alkali metal salt, and water comprises an integrated process which joins extraction and ion exchange steps and a reaction for the conversion of an alkali metal hydroxide. In the initial step the diluent is extracted from the original mixture employing a suitable extractant material. The extract from the initial step containing diluent, extractant material, along with reduced quantities of water and salt, is passed to an ion exchange column for conversion of the alkali metal salt to its hydroxide. In a following fractional distillation dewatering column the diluent begins to react with the alkali metal hydroxide to form an alkali-metal salt of aminocarboxylic acid which can pass harmlessly through the dewatering column for removal in further following fractional distillation step.

Abstract: The present invention provides a method for the recover of a solvent used in the production of a polyarylene sulfide according to which the deterioration of the solvent is low and the recovery rate is high, wherein a mixed liquid, mainly composed of the solvent used in the production of the polyarylene sulfide, and generated from the process of producing the polyarylene sulfide, is subjected to a flash evaporating operation to separate the mixed liquid into a flashed vapor (A) and a flashed residue (B), and then the flashed vapor is rectified (A).

Abstract: The invention relates to a process for separating N-methyl-2-pyrrolidone (NMP) from aqueous solutions which are obtained in industry, inter alia, in the production of heat-resistance polymers such as polyamides and polyimides.According to the invention, the extractants used are phenols which are sparingly soluble in water, are aliphatically monosubstituted and/or polysubstituted in the nucleus and have 4 to 16 carbon atoms in the straight-chain or branched, saturated or unsaturated aliphatic radical and have a boiling point which is preferably at least 20.degree.-25.degree. C. above the boiling point of NMP. If necessary, an inert, viscosity-reducing diluent is added.

Abstract: Pure N-vinyl-2-pyrrolidone is prepared by treating the crude N-vinyl-2-pyrrolidone with an acid ion exchanger.

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

Abstract: A process for recovering N-methyl-2-pyrrolidone from an effluent stream in a poly(arylene sulfide) process containing N-methyl-2-pyrrolidone contaminated with acidic compounds and high boiling contaminants by contacting the kettle liquid from a heavies fractionation zone with an inorganic compound selected from the group consisting of alkaline earth oxides and alkaline earth hydroxides in an amount effective to reduce the acidic compound content of the kettle liquid, and introducing the treated kettle liquid into a thin film evaporation zone to produce an overhead product containing N-methyl-2-pyrrolidone and a bottoms stream containing N-methyl-2-pyrrolidone soluble reaction products of the acidic compounds with the inorganic compound, unreacted acidic compounds and high boiling contaminants.

Abstract: A method for purifying N-methyl-2-pyrrolidone containing thiophenol and/or diphenyl disulfide is disclosed, comprising adding a polyhalogenated aromatic compound and an alkali metal hydroxide and/or an alkali metal carbonate to the N-methyl-2-pyrrolidone containing thiophenol and/or diphenyl disulfide, heat treating the mixture, and subjecting the mixture to separation by distillation. The thiophenol and/or diphenyl disulfide can be removed with ease and at low cost.

Abstract: In a process for recovery N-methyl-2-pyrrolidone from a liquid aqueous medium (preferably a brine) by liquid-liquid extraction, the improvement comprises using a branched aliphatic C5-C7 alcohol as extractant. In a particular embodiment, the liquid aqueous medium is an effluent from a poly(arylene sulfide) process.

Abstract: N-methyl pyrrolidone solvent (hereinafter NMP) used to extract aromatic components from lubricating oil distillates is purified by contacting the solvent with activated alumina.

Abstract: Volatile acids present in n-methyl pyrrolidone vapor from solvent extraction processes can be reacted with sacrificial metals such as magnesium to concentrate the acid salts into a small volume of oil/NMP. Steam stripping removes NMP from the oil/NMP mixture while simultaneously springing a portion of the light carboxylic acids from their salts, the acids going with the NMP. This condensed NMP stream containing the light carboxylic acids is contacted with an ion exchange resin which removes the acids from the NMP. The purified small volume of NMP is returned to the extraction process.

Abstract: A process for drying lactams to extremely low water contents is provided which comprises mixing the lactam with hydrocarbon distilling from the mixture a water/hydrocarbon vapor and or condensate, contacting said vapor or condensate with a drying agent to remove water and returning the dried distillate to the mixture to permit recycling process is capable of providing anionic polymerization grade lactam with a water content of less than about 50 ppm.

Abstract: Compounds of the formula I ##STR1## in which X denotes hydrogen, fluorine, chlorine or bromine, Y and Z denote hydrogen, lower alkyl or lower alkoxy, M denotes sodium, potassium or one equivalent of calcium and L denotes a dipolar aprotic solvent, are obtained from compounds of the formula II ##STR2## in which X, Y and Z have the abovementioned meanings, and a metal cyanamide of the formula IIIM.sub.2 N--CNin which M has the abovementioned meaning, in a dipolar aprotic solvent, which after the reaction is substantially removed, whereupon a lower molecular weight aliphatic alcohol is added to the residue and the product precipitated is isolated. Nitrophenylureas of the formula IV ##STR3## in which X, Y and Z have the abovementioned meanings, are obtained from the compounds of the formula I by acid hydrolysis.