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 the recovery of a light boiler and a heavy boiler from a vapor stream, where the process includes: A1) introducing a vapor stream containing a light boiler and a heavy boiler into a column at a point at the bottom of the column, A2) withdrawing a vapor stream, enriched in the light boiler, from the top of the column, A3) withdrawing a liquid stream, enriched in the heavy boiler, from the bottom of the column, and splitting the stream into a partial stream and a partial stream, A4) recycling the stream back into the column at a point above the column, wherein the stream is kept essentially adiabatically during the recycling, A5) withdrawing a stream, enriched in a middle boiler, from the middle section of the column and splitting the stream into a partial stream and a partial stream, A6) cooling the partial stream in the heat exchanger to provide the cooled stream and recycling the stream as stream back into the column at an introduction point below the top of the column, and A7) withdrawing the

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 method for preparing 3-methylthiopropionaldehyde by reacting methyl mercaptan with acrolein, in which deviations in the stoichiometry of methyl mercaptan to acrolein in the reaction to give 3-methylthiopropionaldehyde are compensated for by supplying or by forming 1,3-bis(methylthio)-1-propanol, and also to the use of 1,3-bis(methylthio)-1-propanol as a storage form of methyl mercaptan and/or 3-methylthiopropionaldehyde.

Abstract: The present invention relates to a method for preparing methionine or methionine salts. In particular, the invention describes the step of preparing 2-hydroxy-4-(methylthio)butyronitrile (MMP-CN) from 3-methylthiopropanal (MMP) and hydrogen cyanide (HCN) in the presence of ammonia by bringing a gaseous mixture comprising HCN and ammonia into contact with MMP.

Abstract: The present invention relates to a method for preparing 3-methylthiopropionaldehyde by reacting methyl mercaptan with acrolein, in which deviations in the stoichiometry of methyl mercaptan to acrolein in the reaction to give 3-methylthiopropionaldehyde are compensated for by supplying or by forming 1,3-bis(methylthio)-1-propanol, and also to the use of 1,3-bis(methylthio)-1-propanol as a storage form of methyl mercaptan and/or 3-methylthiopropionaldehyde.

Abstract: The present invention relates to a method for preparing methionine or methionine salts. In particular, the invention describes the step of preparing 2-hydroxy-4-(methylthio)butyronitrile (MMP-CN) from 3-methylthiopropanal (MMP) and hydrogen cyanide (HCN) in the presence of ammonia by bringing a gaseous mixture comprising HCN and ammonia into contact with MMP.

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).