Abstract: The invention relates to a process for concentrating diluted sulfuric acid (10) which may comprise at least one nitroaromatic compound and/or nitric acid as impurities, comprising: (a) feeding the diluted sulfuric acid (10) into a first stage (1) in which low boilers are removed by evaporation and/or stripping to obtain a first concentrated sulfuric acid (12); (b) optionally feeding the first concentrated sulfuric acid (12) into a second evaporation stage (2) to obtain a second concentrated sulfuric acid (14); (c) feeding the second concentrated sulfuric (14) acid into a third evaporation stage (3) if step (b) is carried out, or feeding the first concentrated sulfuric acid (12) into the third evaporation stage (3) if step (b) is not carried out, to obtain concentrated sulfuric acid (16) as product, wherein an oxidizing agent (17) and/or a precursor of an oxidizing agent is fed into the third evaporation stage (3).

Abstract: A feed supply unit comprising (a) a feed dosage unit for supplying a viscosity unstable liquid feed to a reactor, (b) a flushing unit for flushing at least a part of the feed dosage unit according to (a) with a flushing medium, and (c) a signal transmission means for transmitting a signal from a monitoring means to a control means.

Abstract: Process for scrubbing a crude mixture which is obtained in the nitration of toluene after separating off the nitrating acid and comprises dinitrotoluene, nitric acid, nitrogen oxides and sulfuric acid, which comprises two scrubbing steps (WS-I) and (WS-II), wherein i) in a first scrubbing step (WS-I), the crude mixture is extracted with a scrubbing acid I comprising nitric acid, nitrogen oxides and sulfuric acid in a scrub comprising at least one extraction stage, where the scrubbing acid discharged from the first extraction stage (WS-I-1) of the first scrubbing step (WS-I) has a total acid content of from 10 to 40% by weight and a content of from 80 to 350 ppm of hydrocyanic acid, giving a prescrubbed crude mixture, ii) in a second scrubbing step (WS-II), the prescrubbed crude mixture comprising dinitrotoluene is extracted with a scrubbing acid II in a scrub comprising at least one, preferably at least 2, extraction stage(s), where the scrubbing acid discharged from the first extraction stage (WS-II-1) of th

Abstract: The present invention relates to a process for workup of nitrite-comprising alkaline process wastewaters from the nitration of aromatic compounds, wherein the alkaline process wastewater is acidified by addition of acids and the offgas which comprises nitrogen oxides and escapes from the acidified process wastewater is worked up, comprising the steps of a) acidifying the process wastewater by adding acid to a pH below 5, which forms an organic phase which separates out, an acidic aqueous phase and a gaseous NOx-containing phase, and b) removing the gaseous NOx-containing phase.

Abstract: Process for scrubbing a crude mixture which is obtained in the nitration of toluene after separating off the nitrating acid and comprises dinitrotoluene, nitric acid, nitrogen oxides and sulfuric acid, which comprises two scrubbing steps (WS-I) and (WS-II), wherein i) in a first scrubbing step (WS-I), the crude mixture is extracted with a scrubbing acid I comprising nitric acid, nitrogen oxides and sulfuric acid in a scrub comprising at least one extraction stage, where the scrubbing acid discharged from the first extraction stage (WS-I-1) of the first scrubbing step (WS-I) has a total acid content of from 10 to 40% by weight and a content of from 80 to 350 ppm of hydrocyanic acid, giving a prescrubbed crude mixture, ii) in a second scrubbing step (WS-II), the prescrubbed crude mixture comprising dinitrotoluene is extracted with a scrubbing acid II in a scrub comprising at least one, preferably at least 2, extraction stage(s), where the scrubbing acid discharged from the first extraction stage (WS-II-1) of t

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Abstract: The invention relates to a process for scrubbing a crude mixture comprising dinitrotoluene, nitric acid, nitrogen oxides and sulfuric acid obtained in the nitration of toluene after the nitrating acid has been separated off, which comprises two scrubbing steps (SS-I) and (SS-II), wherein i) in a first scrubbing step (SS-I), the crude mixture is extracted with a scrubbing acid I comprising nitric acid, nitrogen oxides and sulfuric acid in a scrub comprising at least one extraction stage, where the scrubbing acid discharged from the first extraction stage (SS-I-1) of the first scrubbing step (SS-I) has a total acid content of from 20 to 40% by weight and a prescrubbed crude mixture is obtained, ii) in a second scrubbing step (SS-II), the prescrubbed crude mixture comprising dinitrotoluene is extracted with a scrubbing acid II in a scrub comprising at least one extraction stage, where the scrubbing acid discharged from the first extraction stage (SS-II-1) of the second scrubbing step (SS-II) has a pH of less

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Abstract: A business object model, which reflects data that is used during a given business transaction, is utilized to generate interfaces. This business object model facilitates commercial transactions by providing consistent interfaces that are suitable for use across industries, across businesses, and across different departments within a business during a business transaction. In some operations, software creates, updates, or otherwise processes information related to a freight request, a house shipment, a shipment request, a supplier freight invoice request, and/or a transportation booking request business object.

Abstract: A business object model, which reflects data that is used during a given business transaction, is utilized to generate interfaces. This business object model facilitates commercial transactions by providing consistent interfaces that are suitable for use across industries, across businesses, and across different departments within a business during a business transaction. In some operations, software creates, updates, or otherwise processes information related to a freight order, a maintenance plan, a maintenance task list, a request for supplier freight quote, and/or a supplier freight quote business object.

Abstract: Precipitations of nitrohydroxyaromatic salts out of the nitrated crude products obtained in the nitration of aromatic compounds after alkaline scrubbing, for example mononitrotoluenes, are prevented by contacting the nitrated crude products with an acidic ion exchanger. The nitrated crude products are preferably selected from a feedstream to a distillation column, a bottoms circulation stream of a distillation column and a feedstream to a vaporizer.

Abstract: A process for working up alkaline process wastewater from the nitration of aromatic compounds to mono-, di- and trinitroaromatics, said alkaline process wastewater having a pH of 7.5 to 13, comprising the steps of a) acidifying the alkaline process wastewater by adding concentrated sulfuric acid which originates from the workup of the aqueous, sulfuric acid-containing phase obtained in the nitration to a pH below 5, which forms a mixture A consisting of organic phase which separates out and acidic aqueous phase, b) contacting the mixture A with fresh sewage sludge, and c) removing the sewage sludge.

Abstract: A process for working up alkaline process wastewater from the nitration of aromatic compounds to mono-, di- and trinitroaromatics with a pH of 7.5 to 13 or a mixture W with a pH of 6 to 10 of alkaline process wastewater and the aqueous distillate of the sulfuric acid concentration, comprising the steps of a) acidifying the alkaline process wastewater or the mixture W by adding concentrated sulfuric acid which originates from the workup of the aqueous, sulfuric acid-containing phase obtained in the nitration to a pH below 2, which forms a mixture A consisting of organic phase which separates out and acidic aqueous phase, and b) extracting the mixture A with an aromatic extractant.

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Abstract: A process for working up alkaline process wastewater from the nitration of aromatic compounds to mono-, di- and trinitroaromatics, said alkaline process wastewater having a pH of 7.5 to 13, comprising the steps of a) acidifying the alkaline process wastewater by adding concentrated sulfuric acid which originates from the workup of the aqueous, sulfuric acid-containing phase obtained in the nitration to a pH below 5, which forms a mixture A consisting of organic phase which separates out and acidic aqueous phase, b) contacting the mixture A with fresh sewage sludge, and c) removing the sewage sludge.

Abstract: The present invention relates to a process for workup of nitrite-comprising alkaline process wastewaters from the nitration of aromatic compounds, wherein the alkaline process wastewater is acidified by addition of acids and the offgas which comprises nitrogen oxides and escapes from the acidified process wastewater is worked up, comprising the steps of a) acidifying the process wastewater by adding acid to a pH below 5, which forms an organic phase which separates out, an acidic aqueous phase and a gaseous NOx-containing phase, and b) removing the gaseous NOx-containing phase.

Abstract: Precipitations of nitrohydroxyaromatic salts out of the nitrated crude products obtained in the nitration of aromatic compounds after alkaline scrubbing, for example mononitrotoluenes, are prevented by contacting the nitrated crude products with an acidic ion exchanger. The nitrated crude products are preferably selected from a feedstream to a distillation column, a bottoms circulation stream of a distillation column and a feedstream to a vaporizer.

Abstract: A business object model, which reflects data that is used during a given business transaction, is utilized to generate interfaces. This business object model facilitates commercial transactions by providing consistent interfaces that are suitable for use across industries, across businesses, and across different departments within a business during a business transaction. In some operations, software creates, updates, or otherwise processes information related to a freight order, a maintenance plan, a maintenance task list, a request for supplier freight quote, and/or a supplier freight quote business object.

Abstract: The invention relates to a process for the electrochemical treatment of aromatic nitro compounds, which comprises the steps: introducing an aqueous composition comprising at least one aromatic nitro compound into the anode space of an electrolysis cell and carrying out an electrolysis at an anodic current density in the range from 0.1 to 10 kA/m2 and a cell potential in the range from 4 to 15 V.