Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the aqueous 3-hydroxypropionic acid and/or the liquid phase have a high content of oligomeric 3-hydroxypropionic acid.

Abstract: A continuous process for preparing (meth)acrylates of C10-alcohol mixtures by reaction of glacial (meth)acrylic acid with an isomer mixture of C10-alcohols composed of 2-propylheptanol as the main isomer and at least one of the C10-alcohols 2-propyl-4-methylhexanol, 2-propyl-5-methylhexanol, 2-isopropylheptanol, 2-isopropyl-4-methylhexanol, 2-isopropyl-5-methylhexanol and/or 2-propyl-4,4-dimethylpentanol, and the use of a diester of dicarboxylic acids which have been esterified with N-oxyl-containing compounds as polymerization inhibitors in such a process.

Abstract: A process is described for the preparation of 5-hydroxymethylfurfural (HMF), which comprises the following steps: provision or preparation of a starting mixture, comprising one, two or more starting compounds selected from the group consisting of hexoses, oligosaccharides comprising hexose units, and polysaccharides comprising hexose units, one, two or more organic salts with a melting point <180° C. and a boiling point >200° C. at 1013.25 hPa, optionally additionally one or more catalysts for the conversion of the one starting compound or at least one of the two or more starting compounds to 5-hydroxymethylfurfural (HMF), optionally water, optionally further substances, adjustment of reaction conditions such that an amount of the starting compound or starting compounds converts to HMF.

Abstract: What is proposed is a continuous process for discharging a solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates from the product mixture from the preparation of N,N-dimethylacetamide (DMAC) by reaction of methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a catalyst comprising N,N-dimethylacetamide (DMAC), methyl acetate (MeOAc), dimethylamine (DMA) and a catalyst, having the following process steps: level-regulated feeding of the product mixture as feed stream into an evaporation vessel of a forced circulation evaporator, flash evaporation of volatile components of the product mixture in the forced circulation evaporator to form a vapor phase comprising N,N-dimethylacetamide (DMAC) and precipitation of a solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates, recycling of the volatile components of the product mixture obtained after the flash evaporation, removal of a vapor phase comprising N,N-dimethyl

Abstract: A process is described for the preparation of 5-hydroxymethylfurfural (HMF), which comprises the following steps: provision or preparation of a starting mixture, comprising one, two or more starting compounds selected from the group consisting of hexoses, oligosaccharides comprising hexose units, and polysaccharides comprising hexose units, one, two or more organic salts with a melting point <180° C. and a boiling point >200° C. at 1013.25 hPa, optionally additionally one or more catalysts for the conversion of the one starting compound or at least one of the two or more starting compounds to 5-hydroxymethylfurfural (HMF), optionally water, optionally further substances, adjustment of reaction conditions such that an amount of the starting compound or starting compounds converts to HMF.

Abstract: A continuous process for preparing (meth)acrylates of C10-alcohol mixtures by reaction of glacial (meth)acrylic acid with an isomer mixture of C10-alcohols composed of 2-propylheptanol as the main isomer and at least one of the C10-alcohols 2-propyl-4-methylhexanol, 2-propyl-5-methylhexanol, 2-isopropylheptanol, 2-isopropyl-4-methylhexanol, 2-isopropyl-5-methylhexanol and/or 2-propyl-4,4-dimethylpentanol, and the use of a diester of dicarboxylic acids which have been esterified with N-oxyl-containing compounds as polymerization inhibitors in such a process.

Abstract: Process for recovering cyclododecatriene (CDT) from a solution containing CDT and high boilers such as deactivated catalyst and polymers, which includes feeding the solution into a preheater and heating it, subsequently depressurizing it through a downstream pressure maintenance device and feeding the resulting two-phase mixture into a helical tube evaporator and there reducing the CDT content of the liquid phase by partial evaporation and discharging a gaseous product stream having an increased concentration of CDT.

Abstract: Process for preparing a solution of pure triethylenediamine (TEDA), in which TEDA is vaporized, the gaseous TEDA is passed into a liquid solvent 1 (quench) and the TEDA is crystallized from the resulting solution and separated off (solid-liquid separation), wherein the crystalline TEDA obtained is dissolved in a solvent 2 and a stripping gas is passed through the resulting solution (stripping).

Abstract: The present invention relates to a process for working up triethylenediamine (TEDA) in which TEDA is vaporized and the gaseous TEDA is introduced into a solvent, subsequently crystallized and separated off from this and the mother liquor formed is extracted with an extractant, wherein the raffinate phase obtained after the extraction stage is worked up further by adsorption in which extractant and/or by-products and intermediates present in the raffinate phase are removed therefrom.

Abstract: Process for recovering cyclododecatriene (CDT) from a solution comprising CDT and high boilers such as deactivated catalyst and polymers, which comprises feeding the solution into a preheater and heating it, subsequently depressurizing it through a downstream pressure maintenance device and feeding the resulting two-phase mixture into a helical tube evaporator and there reducing the CDT content of the liquid phase by partial evaporation and discharging a gaseous product stream having an increased concentration of CDT.

Abstract: In a process for the purification of triethylenediamine (TEDA) in which TEDA is vaporized and the gaseous TEDA is passed into a liquid solvent and is subsequently crystallized from this, the mother liquor obtained after the TEDA has been crystallized is extracted with an extractant which is immiscible or only slightly miscible with the solvent of the mother liquor and in which TEDA is readily soluble, and the TEDA-depleted mother liquor obtained after extraction and/or the TEDA-enriched extractant which has been used for the extraction are/is returned to the process.

Abstract: A process for preparing a high-concentration formaldehyde solution by removing water from a lower-concentration formaldehyde solution having a formaldehyde content of from 5 to 50% by weight, in which the lower-concentration formaldehyde solution is fed to a preheater and heated in the preheater, depressurized via a pressure maintenance device and concentrated in a helical tube evaporator to give a vapor stream and the high-concentration formaldehyde solution as bottom stream, wherein the heated lower-concentration formaldehyde hyde solution is depressurized in the pressure maintenance device to give a two-phase mixture which is fed into the helical tube evaporator, is proposed.

Abstract: Process for preparing a solution of pure triethylenediamine (TEDA), in which TEDA is vaporized, the gaseous TEDA is passed into a liquid solvent 1 (quench) and the TEDA is crystallized from the resulting solution and separated off (solid-liquid separation), wherein the crystalline TEDA obtained is dissolved in a solvent 2 and a stripping gas is passed through the resulting solution (stripping).

Abstract: The invention relates to a process for continuously, distillatively removing piperazine from an ethylenediamine-piperazine mixture under pressure at elevated temperature, by discharging the ethylenediamine at the top and the piperazine at the bottom of a distillation column. For the purpose of improving the quality of the piperazine, especially its color and color stability, the piperazine is subjected directly to circulation conveying it through an evaporator unit operated at a temperature of from about 160° C. to about 170° C. and returning it into the distillation column. After a residence time of from about 30 min to about 60 min in the circulation system, the piperazine is discharged in vapor form from a side draw in the lower section of the distillation column.

Abstract: A process for preparing a high-concentration formaldehyde solution by removing water from a lower-concentration formaldehyde solution having a formaldehyde content of from 5 to 50% by weight, in which the lower-concentration formaldehyde solution is fed to a preheater and heated in the preheater, depressurized via a pressure maintenance device and concentrated in a helical tube evaporator to give a vapor stream and the high-concentration formaldehyde solution as bottom stream, wherein the heated lower-concentration formaldehyde hyde solution is depressurized in the pressure maintenance device to give a two-phase mixture which is fed into the helical tube evaporator, is proposed.

Abstract: The invention relates to a process for continuously, distillatively removing piperazine from an ethylenediamine-piperazine mixture under pressure at elevated temperature, by discharging the ethylenediamine at the top and the piperazine at the bottom of a distillation column. For the purpose of improving the quality of the piperazine, especially its color and color stability, the piperazine is subjected directly to circulation conveying it through an evaporator unit operated at a temperature of from about 160° C. to about 170° C. and returning it into the distillation column. After a residence time of from about 30 min to about 60 min in the circulation system, the piperazine is discharged in vapor form from a side draw in the lower section of the distillation column.

Abstract: Highly pure triethylenediamine is obtained by a process in which triethylenediamine is freed from high boilers and then the triethylenediamine is vaporized from the mixture thus obtained and is passed into a liquid solvent. The process makes it possible in particular to obtain highly pure solutions of triethylenediamine. Crystallization is generally unnecessary.

Abstract: Process for purifying triethylenediamine (TEDA) by disillation, in which the fractionation is carried out in a dividing wall column.

Abstract: The present invention describes a process for the preparation of triethylenediamine by reacting piperazine over a zeolite catalyst which, in addition to SiO2, contains an oxide of at least one further divalent, trivalent or tetravalent metal M, wherein the zeolite has a molar Si/M ratio of >100. In particular, a zeolite of the ZSM-5 type is used. The use of the zeolites permits suppression of the undesired formation of the byproduct 2-ethylpiperazine and hence considerable simplification of the working-up, in combination with high piperazine conversions and a small excess of water.

Abstract: The present invention describes a process for the preparation of triethylenediamine by reacting piperazine over a zeolite catalyst which, in addition to SiO2, contains an oxide of at least one further divalent, trivalent or tetravalent metal M, wherein the zeolite has a molar Si/M ratio of >100. In particular, a zeolite of the ZSM-5 type is used. The use of the zeolites permits suppression of the undesired formation of the byproduct 2-ethylpiperazine and hence considerable simplification of the working-up, in combination with high piperazine conversions and a small excess of water.