Abstract: A process is proposed for reprocessing the exhaust gas from a plant for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen for the purpose of utilization of at least a part of the nitrogen monoxide and if appropriate hydrogen present in the exhaust gas for producing hydroxylamine or hydroxylammonium salts, which comprises, in a first separation stage, selectively separating off nitrogen monoxide from the exhaust gas of the plant for producing hydroxylamine or hydroxylammonium salts.

Abstract: A process is proposed for reprocessing the exhaust gas from a plant for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen for the purpose of utilization of at least a part of the nitrogen monoxide and if appropriate hydrogen present in the exhaust gas for producing hydroxylamine or hydroxylammonium salts, which comprises, in a first separation stage, selectively separating off nitrogen monoxide from the exhaust gas of the plant for producing hydroxylamine or hydroxylammonium salts.

Abstract: A process is proposed for the distillation or reactive distillation of a mixture that includes at least one toxic component, the process being carried out in a column containing a structured packing, having at least one packing layer (1) having a lower end (2) and an upper end (3), the packing layer having an internal geometry varying over its height, in such a manner that in the distillation or reactive distillation, in a first, lower region (6) of the packing layer (1) a bubbling layer having a predominantly disperse gas phase can be established and simultaneously in a second, upper region (7) of the packing layer (1) a film flow having a predominantly continuous gas phase can be established.

Abstract: A process is proposed for the separation of C5+ cuts by distillation into a low-boiler (A), a medium-boiler (B) and a high-boiler fraction (C) in one or more dividing-wall columns (TK), in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper, common column region (1), a lower, common column region (6), a feed part (2, 4) with rectifying section (2) and stripping section (4), and a withdrawal part (3, 5) with rectifying section (5) and stripping section (3), with feed of the C5+ cut (A, B, C) into the central region of the feed part (2, 4), discharge of the high-boiler fraction (C) from the bottom of the column, discharge of the low-boiler fraction (A) via the top of the column, and discharge of the medium-boiler fraction (B) from the central region of the withdrawal part (3, 5), wherein the dividing ratio of the liquid reflux at the upper end of the dividing wall (T) is set in such a way that the proportion of high-boiling key components in the liquid re

Abstract: A process for oxidizing a starting material with an oxidizing agent to obtain a product, which comprises carrying out the oxidation in a reaction apparatus which has a bottom region at the lower end, a top region at the upper end and a reaction zone between the top region and the bottom region, maintaining the reaction mixture in the boiling state in the reaction zone, and introducing oxidizing agent into the reaction zone in at least two substreams.

Abstract: Propene and, if desired, 1-butene are prepared by a) reacting 1-butene and 2-butene to give propene and 2-pentene in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VIb, VIIb or VIII of the Periodic Table of the Elements, b) subsequently separating the propene and 2-pentene formed, c) subsequently reacting the 2-pentene with ethene to give propene and 1-butene in the presence of a metathesis catalyst comprising at least one compound of a metal of transition group VIb, VIIb or VIII of the Periodic Table of the Elements, d) subsequently separating the propene and 1-butene formed, e) discharging at least some of the 1-butene formed and/or at least partly isomerizing the 1-butene formed to give 2-butene in the presence of an isomerization catalyst and subsequently returning the undischarged 1-butene and the 2-butene formed together with a part of the C4 fraction not reacted in step a) to step a).

Abstract: Higher &agr;,&bgr;-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetates diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.

Abstract: A process is described for continuously preparing chromanol ester derivatives, in particular for continuously preparing carboxylic esters of tocopherols and tocotrienols by continuous acylation with carboxylic acids or carboxylic anhydrides.

Abstract: A process is proposed for the distillation or reactive distillation of a mixture that comprises at least one toxic component, the process being carried out in a column containing a structured packing, having at least one packing layer (1) having a lower end (2) and an upper end (3), the packing layer having an internal geometry varying over its height, in such a manner that in the distillation or reactive distillation, in a first, lower region (6) of the packing layer (1) a bubbling layer having a predominantly disperse gas phase can be established and simultaneously in a second, upper region (7) of the packing layer (1) a film flow having a predominantly continuous gas phase can be established.

Abstract: The invention provides a microstructured, self-cleaning, catalytically active surface with elevations and depressions, comprising a catalytically active material in the depressions.

Abstract: In a process for hydrogenating unsubstituted monocyclic or polycyclic aromatics or monocyclic or polycyclic aromatics substituted by at least one alkyl group, amino group or hydroxyl group or a combination of two or more thereof to form the corresponding cycloaliphatics by means of gaseous hydrogen in the presence of at least one catalyst in a reaction column (4) in which the reactants are passed over the catalyst(s) (5) fixed in the reaction column (4), the cycloaliphatics are taken off at a side offtake (14) or from the bottom of the column (6) through a line (8) or at the side offtake (14) and from the bottom of the column (6) through a line (8).

Abstract: A process is described for continuously preparing chromanol ester derivatives, in particular for continuously preparing carboxylic esters of tocopherols and tocotrienols by continuous acylation with carboxylic acids or carboxylic anhydrides.

Abstract: A process is proposed for the separation of C5+ cuts by distillation into a low-boiler (A), a medium-boiler (B) and a high-boiler fraction (C) in one or more dividing-wall columns (TK), in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper, common column region (1), a lower, common column region (6), a feed part (2, 4) with rectifying section (2) and stripping section (4), and a withdrawal part (3, 5) with rectifying section (5) and stripping section (3), with feed of the C5+ cut (A, B, C) into the central region of the feed part (2, 4), discharge of the high-boiler fraction (C) from the bottom of the column, discharge of the low-boiler fraction (A) via the top of the column, and discharge of the medium-boiler fraction (B) from the central region of the withdrawal part (3, 5), wherein the dividing ratio of the liquid reflux at the upper end of the dividing wall (T) is set in such a way that the proportion of high-boiling key components in the

Abstract: In a process for the continuous preparation of glutaraldehyde by reaction of an alkoxydihydropyran of the formula I where R is C1-C20-alkyl, with water at from 0° C. to 200° C. and a pressure in the range from 0.01 bar to 16 bar to form glutaraldehyde and the alcohol corresponding to the alkoxy group, water and alkoxydihydropyran are fed continuously to a reaction column and a distillate enriched in the alcohol corresponding to the alkoxy group is taken off at the top of the column and a product enriched in glutaraldehyde is taken off at the bottom. This process makes it possible to prepare glutaraldehyde or C-substituted glutaraldehydes continuously in high purity in a simple manner with a low outlay in terms of apparatus.

Abstract: Propene and, if desired, 1-butene are prepared by

Abstract: Higher &agr;,&bgr;-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetatesor diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.

Abstract: Propene and, if desired, 1-butene are prepared by first reacting 1-butene and 2-butene to give propene and 2-pentene in the presence of a metathesis catalyst containing at least one compound of a metal of transition group VIb, VIIb or VIII of the Periodic Table of the Elements. The propene and 2-pentene formed are subsequently separated, and the 2-pentene is then reacted to give propene and 1-butene in the presence of a metathesis catalyst containing at least one compound of a metal of transition group VIb, VIIb or VIII. The propene and 1-butene formed are subsequently separated, and at least some of the 1-butene is discharged or at least partly isomerized to give 2-butene in the presence of an isomerization catalyst. Undischarged 1-butene and the 2-butene formed are subsequently returned to the initial reaction step, together with that part of the C4 fraction which was not reacted in the initial reaction step.

Abstract: Process for the continuous preparation of unsaturated ketones of the formula I where the dashed line can be an additional C—C bond, R1 is an alkyl, and R2 is an aliphatic hydrocarbon having from 1 to 37 carbons, a cycloalkyl or a cycloalkylalkyl, by reacting an unsaturated alcohol of the formula II  with an alkyl acetoacetate of the formula III where R3 is an alkyl having from 1 to 5 carbons, in the presence or organic aluminum compounds as catalyst.

Abstract: The invention provides an evaporator having a heatable heat exchange surface, which has a self-cleaning microstructured surface with elevations and depressions.

Abstract: An improved process for preparing lower unsaturated ketones by reacting the corresponding &agr;,&bgr;-unsaturated alcohols with alkyl acetoacetates in a Carroll reaction in the presence of from 0.1 to 5 mol %, based on the alkyl acetoacetate to be reacted, of an organic aluminum compound as catalyst with elimination and continuous removal by distillation of the alkanol eliminated during the reaction from the alkyl acetoacetate in a reactor system with a fitted fractionation column, wherein A an &agr;,&bgr;-unsaturated alcohol which boils below 140° C. is introduced, in the absence of effective amounts of a solvent, together with the organic aluminum compound into the reaction vessel, B a reaction temperature which is as constant as possible between 170° C. and 250° C.