Abstract: The invention relates to a process for distillatively purifying crude dimethylacetamide (crude DMAc) comprising DMAc, low boilers and high boilers 5 by removing the low boilers and the high boilers to obtain pure DMAc in one of the column configurations listed hereinbelow: (I) a main column (MC) with sidestream column (SC) or (II) a dividing wall column (DWC), which operating at least the main column (MC) in column configuration (I) and the dividing wall column (DWC) in column configuration (II) at a top pressure in the range from 0.5 to 1.8 bar absolute.

Abstract: Processes for chemical reaction and separation in a column comprising, (a) providing one or more reactants to a column; and (b) carrying out at least partially superimposed reactive distillation and extractive distillation on the one or more reactants in the column to form a reaction product mixture comprising at least two components and separate at least one of the components; wherein an ionic liquid is present in the column.

Abstract: Process for working up a bottom stream wherein high boilers and ionic liquid from an extractive rectification in which the ionic liquid is used as entrainer. The process includes feeding the bottom stream to an evaporation stage which is operated at a pressure of less than 500 mbar or to a stripper which is operated through use of inert gas or steam, and the major part of the high boiler present is separated off in vapor form from the ionic liquid.

Abstract: A process for separating azeotropic or close-boiling mixtures by means of an extractive rectification in which an ionic liquid is used as entrainer, wherein a high boiling bottom product is taken off from the column in vapor form via a side offtake.

Abstract: The invention relates to a process for distillatively purifying crude dimethylacetamide (crude DMAc) comprising DMAc, low boilers and high boilers 5 by removing the low boilers and the high boilers to obtain pure DMAc in one of the column configurations listed hereinbelow: (I) a main column (MC) with sidestream column (SC) or (II) a dividing wall column (DWC), which comprises operating at least the main column (MC) in column configuration (I) and the dividing wall column (DWC) in column configuration (II) at a top pressure in the range from 0.5 to 1.8 bar absolute.

Abstract: Pure triethylenediamine (TEDA) is prepared by vaporizing TEDA, introducing the gaseous TEDA into a liquid solvent and subsequently crystallizing the TEDA from the solution obtained in this way.

Abstract: Anhydrous or substantially anhydrous formic acid is obtained by hydrolysis of methyl formate, in a process wherein(a) methyl formate is hydrolyzed,(b) the methanol and excess methyl formate are distilled from the hydrolysis mixture obtained,(c) the bottom product of distillation (b), consisting of formic acid and water, is extracted, in a liquid-liquid extraction, with an extractant which in the main takes up the formic acid,(d) the resulting extract phase, consisting of formic acid, the extractant and a part of the water, is subjected to distillation,(e) the top product obtained from this distillation and consisting of all or part of the water introduced into the distillation, and part of the formic acid, is recycled, as vapor, into the lower part of the distillation column of stage (b),(f) the bottom product of distillation stage (d), consisting of the extractant, with or without part of the water, and the greater part of the formic acid, is separated by distillation into anhydrous or substantially anhydrou