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 theoretical plate and ending at least two theoretical plates below the uppermost theoretical plate, the side offtake point (3) for the pure 2-ethylhexyl acrylate or pure 2-propylheptyl 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 two theoretical plates below the uppermost theoretical plate and the dividing wall (8) is arranged in the column in the region commencing at least one theoretical plate above the bottommost theoretical plate and ending at least one theoretical plate below the uppermost theoretical plate, where the ratio of amount of liquid at the upper end of the dividing wall (8) going to the enrichment section (10) and the stripping section (11) of the column is set in the range from 1:0.2 to 1:5.
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 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. below the condensation temperature of the tert-butyl ester at the second pressure, with the proviso that the second temperature is at least 5° C. below the first temperature; and d) the combination of the first condensate (K1) and the second condensate (K2) and the feeding to a combined workup, and recycling of the third vapor (B3) not condensed at the second temperature into step a). The process allows the preparation of the tert-butyl ester of an aliphatic C1-C4 carboxylic acid by reaction of the carboxylic acid with isobutene, with isolation of unconverted isobutene from the esterification mixture in an energetically favorable manner and with an improved degree of removal.
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 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. below the condensation temperature of the tert-butyl ester at the second pressure, with the proviso that the second temperature is at least 5° C. below the first temperature; and d) the combination of the first condensate (K1) and the second condensate (K2) and the feeding to a combined workup, and recycling of the third vapor (B3) not condensed at the second temperature into step a). The process allows the preparation of the tert-butyl ester of an aliphatic C1-C4 carboxylic acid by reaction of the carboxylic acid with isobutene, with isolation of unconverted isobutene from the esterification mixture in an energetically favorable manner and with an improved degree of removal.
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 a heater; a superheated, liquid recycle stream is taken from the heater; and the superheated recycle stream is let down into the distillation apparatus; and d5) at least in the top region of the distillation apparatus, the distillation apparatus walls in contact with the vapor, at least in sub-regions, are heated and/or thermally insulated. In the course of the process, the separation of the tert-butyl ester from unreacted carboxylic acid is carried on with a particularly low level of accompanying polymerization both of the tert-butyl ester and of the carboxylic acid.
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.