Abstract: A process for isolating pure tert-butyl (meth)acrylate from crude tert-butyl (meth)acrylate by distillation, wherein the process is carried out in a dividing wall column having separation-active internals and a vaporizer and in which a dividing wall is arranged in the longitudinal direction of the column to form an upper joint column region, a lower joint column region, an inflow section having a side feed point, and an offtake section having a side offtake point, where the column has from 20-80 theoretical plates and the ratio of the amount of liquid at the upper end of the dividing wall going to the enrichment section and the stripping section of the column is set in the range from 1:0.2 to 1:5.

Abstract: A process for continuously preparing a butyl acrylate H2C?CH—C(?O)OR, with R=n-butyl or isobutyl, wherein aqueous 3-hydroxypropionic acid is converted under dehydrating and esterifying conditions in the presence of the corresponding butanol R—OH in a reactor with a rectification column and butyl acrylate formed, unconverted butanol and water used and formed are distilled off overhead as a ternary azeotrope, after separation into a liquid aqueous phase and liquid organic phase each of the aqueous and organic phases is at least partly discharged, and the organic phase comprising the butyl acrylate and the butanol is subjected to distillative separation.

Abstract: A process for isolating pure butyl acrylate from crude butyl acrylate, which is carried out in a dividing wall column having separation-active internals and a vaporizer, and in which: a dividing wall is arranged in a longitudinal direction of the column to form an upper joint column region, a lower joint column region, an inflow section having a side feed point and an offtake section having a side offtake point; a ratio of an amount of liquid at an upper end of the dividing wall going to an enrichment section and a stripping section of the column is set in the range from 1:0.2 to 1:5; and a ratio of an amount of vapor streams at a lower end of the dividing wall going to the stripping section and the enrichment section of the column is set in a range from 1:0.5 to 1:2.0.

Abstract: Process for isolating pure 2-ethylhexyl acrylate or pure 2-propylheptyl acrylate from the corresponding crude alkyl acrylate by distillation, wherein the process is carried out in a dividing wall column (1) which has separation-active internals and vaporizer (7) and in which a dividing wall (8) is arranged in the longitudinal direction of the column to form an upper joint column region (9), a lower joint column region (14), an inflow section (10, 12) having a side feed point (2) and an offtake section (11, 13) having a side offtake point (3), the column has a number of theoretical plates in the range from 10 to 60, where the number of theoretical plates of the dividing wall column (1) relates to the sum of the theoretical plates in the joint upper column region (9), the joint lower column region (14) and the inflow section (10, 12), the side feed point (2) for the corresponding crude alkyl acrylate is arranged at a theoretical plate in the region commencing at least two theoretical plates above the bottommost

Abstract: Process for isolating pure tert-butyl (meth)acrylate from crude tert-butyl (meth)acrylate by distillation, wherein the process is carried out in a dividing wall column (1) which has separation-active internals and vaporizer (7) and in which a dividing wall (8) is arranged in the longitudinal direction of the column to form an upper joint column region (9), a lower joint column region (14), an inflow section (10, 12) having a side feed point (2) and an offtake section (11, 13) having a side offtake point (3), the column has a number of theoretical plates in the range from 20 to 80, where the number of theoretical plates of the dividing wall column (1) relates to the sum of the theoretical plates in the joint upper column region (9), the joint lower column region (14) and the inflow section (10, 12), the side feed point (2) for the crude tert-butyl (meth)acrylate is arranged at a theoretical plate in the region commencing at least two theoretical plates above the bottommost theoretical plate and ending at least

Abstract: A process for continuously preparing the tert-butyl ester of an ethylenically unsaturated carboxylic acid, by a) reacting an ethylenically unsaturated carboxylic acid with isobutene in the presence of an acidic catalyst to give an esterification mixture; b) removing the acidic catalyst; c) removing low-boiling components; and d) supplying a tert-butyl ester-comprising liquid to a distillation apparatus and subjecting it to purifying distillation in the distillation apparatus, where d1) in the distillation apparatus the tert-butyl ester-comprising liquid is separated into a tert-butyl ester-comprising gaseous top product and a carboxylic acid-comprising liquid bottom product; d2) the tert-butyl ester-comprising gaseous top product is at least partly condensed and the condensate is recycled partly as reflux to the distillation apparatus; d3) the carboxylic acid-comprising liquid bottom product is recycled at least partly to step a); d4) carboxylic acid-comprising liquid bottom product is drawn off and passed to

Abstract: A process for continuously preparing the tert-butyl ester of an ethylenically unsaturated carboxylic acid, by a) reacting an ethylenically unsaturated carboxylic acid with isobutene in the presence of an acidic catalyst to give an esterification mixture; b) removing the acidic catalyst; c) removing low-boiling components; and d) supplying a tert-butyl ester-comprising liquid to a distillation apparatus and subjecting it to purifying distillation in the distillation apparatus, where d1) in the distillation apparatus the tert-butyl ester-comprising liquid is separated into a tert-butyl ester-comprising gaseous top product and a carboxylic acid-comprising liquid bottom product; d2) the tert-butyl ester-comprising gaseous top product is at least partly condensed and the condensate is recycled partly as reflux to the distillation apparatus; d3) the carboxylic acid-comprising liquid bottom product is recycled at least partly to step a); d4) carboxylic acid-comprising liquid bottom product is drawn off and passed to

Abstract: A process for continuously preparing the tert-butyl ester of an aliphatic C1-C4 carboxylic acid comprises: a) the reaction of an aliphatic C1-C4 carboxylic acid with isobutene in the presence of an acidic catalyst to give an esterification mixture (G1); b) the partial evaporation of the esterification mixture (G1), giving a liquid first high boiler phase (SPh1) comprising the acidic catalyst, and a first vapor (B1) comprising tert-butyl ester; c) the fractional condensation of the first vapor (B1) by partially condensing the first vapor (B1) at a first pressure and a first temperature and obtaining a first condensate (K1), partially condensing the uncondensed second vapor (B2) at a second pressure and a second temperature and obtaining a second condensate (K2), the first temperature being 0 to 45° C. below the condensation temperature of the tert-butyl ester at the first pressure and the second temperature being 45 to 80° C.

Abstract: A process for continuously preparing the tert-butyl ester of an aliphatic C1-C4 carboxylic acid comprises: a) the reaction of an aliphatic C1-C4 carboxylic acid with isobutene in the presence of an acidic catalyst to give an esterification mixture (G1); b) the partial evaporation of the esterification mixture (G1), giving a liquid first high boiler phase (SPh1) comprising the acidic catalyst, and a first vapor (B1) comprising tert-butyl ester; c) the fractional condensation of the first vapor (B1) by partially condensing the first vapor (B1) at a first pressure and a first temperature and obtaining a first condensate (K1), partially condensing the uncondensed second vapor (B2) at a second pressure and a second temperature and obtaining a second condensate (K2), the first temperature being 0 to 45° C. below the condensation temperature of the tert-butyl ester at the first pressure and the second temperature being 45 to 80° C.

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 for continuously producing water-absorbing polymer particles, wherein the monomer stems from at least two different sources and the monomer from one source differs from the monomer from at least one other source in the content of at least one secondary component.

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 shell which encloses an interior and has at least one first orifice for feeding at least one gas stream into the interior and at least one second orifice for withdrawing a gas stream fed to the interior beforehand via the at least one first orifice from the interior, the surface of the shell, on its side in contact with the interior, being manufactured at least partly, in a layer thickness of at least 1 mm, from a steel which has a specific elemental composition, and in the interior, a process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated is carried out in a reactor which is manufactured from the steel on its side in contact with the reaction gas.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.

Abstract: A process for preparing at least one partial oxidation and/or ammoxidation product of a hydrocarbon by partially dehydrogenating at least one saturated hydrocarbon H under heterogeneous catalysis and using the resulting product gas mixture A, which comprises the partially dehydrogenated hydrocarbon H, as such or in modified form for heterogeneously catalyzed partial oxidation and/or ammoxidation of the partially dehydrogenated hydrocarbon present in the product gas mixture A, said process including at least one mechanical separating operation inserted between the product gas mixture A and the heterogeneously catalyzed partial oxidation and/or ammoxidation.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for heterogeneously catalyzed partial dehydrogenation of a hydrocarbon, in which a reaction gas mixture input stream comprising the hydrocarbon to be dehydrogenated is conducted through a fixed catalyst bed disposed in a shaft and the reaction gas mixture input stream is obtained in the shaft by metering an input gas II comprising molecular oxygen upstream of the fixed catalyst bed into an input gas stream I which comprises molecular hydrogen and the hydrocarbon to be dehydrogenated and is flowing within the shaft toward the fixed catalyst bed.

Abstract: A process for heterogeneously catalyzed partial dehydrogenation of a hydrocarbon, in which a reaction gas mixture input stream comprising the hydrocarbon to be dehydrogenated is conducted through a fixed catalyst bed disposed in a shaft and the reaction gas mixture input stream is obtained in the shaft by metering an input gas II comprising molecular oxygen upstream of the fixed catalyst bed into an input gas stream I which comprises molecular hydrogen and the hydrocarbon to be dehydrogenated and is flowing within the shaft toward the fixed catalyst bed.