Abstract: The present invention relates to a process for the purification of hydrogen cyanide, comprising the steps of a) splitting a liquid feed stream (1) comprising hydrogen cyanide into at least a first liquid stream (2) and a second liquid stream (3), b) introducing the first liquid stream (2) into a distillation column (4) at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream (3) into the distillation column (4) at the top of the distillation column, d) withdrawing an overhead vapor stream (5) enriched in hydrogen cyanide from the distillation column (4), and e), withdrawing a bottom stream (6) depleted in hydrogen cyanide, wherein the temperature of the second liquid stream (3) in step c) is lower than the temperature of the first liquid stream (2) in step b).

Abstract: A process for preparing 3-methylthiopropionaldehyde, by a) providing a liquid stream with methyl mercaptan and/or the hemi thioacetal formed from 3-methylthiopropionaldehyde and methyl mercaptan; b) providing an acrolein with a vapor stream, where the major part of the vapor stream is acrolein, and the pressure of the vapor stream is lower than atmospheric pressure; c) introducing the liquid stream with methyl mercaptan and/or the hemi thioacetal formed from 3-methylthiopropionaldehyde and methyl mercaptan of a) and the acrolein with a vapor stream of b) into a reaction unit with a vapor-liquid mixing device, and d) reacting acrolein with methyl mercaptan and/or the hemi thioacetal formed from 3-methylthiopropionaldehyde and methyl mercaptan in the reaction unit of c) to give a 3-metyhlthiopropionaldehyde product mixture.

Abstract: The present invention relates to a process for the purification of hydrogen cyanide, comprising the steps of a) splitting a liquid feed stream (1) comprising hydrogen cyanide into at least a first liquid stream (2) and a second liquid stream (3), b) introducing the first liquid stream (2) into a distillation column (4) at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream (3) into the distillation column (4) at the top of the distillation column, d) withdrawing an overhead vapor stream (5) enriched in hydrogen cyanide from the distillation column (4), and e), withdrawing a bottom stream (6) depleted in hydrogen cyanide, wherein the temperature of the second liquid stream (3) in step c) is lower than the temperature of the first liquid stream (2) in step b).

Abstract: The present invention relates to a process for purifying acrolein. The process includes the steps of a) splitting a liquid feed stream containing acrolein into at least a first liquid stream and a second liquid stream, b) introducing the first liquid stream with a temperature T1 into a distillation column at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream with a temperature T2 into the distillation column at the top of the distillation column, d) withdrawing an overhead vapor stream enriched in acrolein from the distillation column, and e) withdrawing a bottom stream depleted in acrolein. The temperature T2 of the second liquid stream in step c) is lower than the temperature T1 of the first liquid stream in step b).

Abstract: The present invention relates to a process for purifying acrolein. The process includes the steps of a) splitting a liquid feed stream containing acrolein into at least a first liquid stream and a second liquid stream, b) introducing the first liquid stream with a temperature T1 into a distillation column at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream with a temperature T2 into the distillation column at the top of the distillation column, d) withdrawing an overhead vapor stream enriched in acrolein from the distillation column, and e) withdrawing a bottom stream depleted in acrolein. The temperature T2 of the second liquid stream in step c) is lower than the temperature T1 of the first liquid stream in step b).