Method for preparing 3-methylthiopropionaldehyde

Patent metadata

Field	Value
Publication number	US-11014878-B2
Application number	US-201716076247-A
Country	US
Kind code	B2
Filing date	Feb 14, 2017
Priority date	Feb 15, 2016
Publication date	May 25, 2021
Grant date	May 25, 2021

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.

First claim

The invention claimed is:

1. A method for continuously preparing 3-methylthiopropionaldehyde, the method comprising:
reacting methyl mercaptan with acrolein to obtain the 3-methylthiopropionaldehyde,
wherein deviations in a stoichiometry of the methyl mercaptan to the acrolein during the reacting to obtain the 3-methylthiopropionaldehyde are compensated for by supplying or forming 1,3-bis(methylthio)-1-propanol, and
wherein:
if the methyl mercaptan is present in excess with respect to the acrolein, an excess methyl mercaptan is converted to the 1,3-bis(methylthio)-1-propanol with the 3-methylthiopropionaldehyde, wherein the 1,3-bis(methylthio)-1-propanol formed is intermediately stored,
or
if the acrolein is present in excess with respect to the methyl mercaptan, the 1,3-bis(methylthio)-1-propanol is supplied to the reacting of the methyl mercaptan with the acrolein, wherein a molar amount of intermediately stored 1,3-bis(methylthio)-1-propanol to be supplied is at least as large as an amount of an excess acrolein.

2. The method according to claim 1 , wherein a molar ratio of the methyl mercaptan to the 3-methylthiopropionaldehyde during the reacting to obtain the 1,3-bis(methylthio)-1-propanol is from 0.1:1 (mol/mol) to 1:1 (mol/mol).

3. The method according to claim 1 , wherein an excess acrolein is present and the excess acrolein is reacted with the 1,3-bis(methylthio)-1-propanol to obtain the 3-methylthiopropionaldehyde.

4. The method according to claim 1 , wherein a portion of a stream comprising the methyl mercaptan is branched off before the reacting to obtain the 3-methylthiopropionaldehyde and is supplied to the forming of the 1,3-bis(methylthio)-1-propanol by reacting the 3-methylthiopropionaldehyde with the methyl mercaptan.

5. The method according to claim 1 , wherein a minimum stream of the methyl mercaptan is branched off before the reacting to obtain the 3-methylthiopropionaldehyde and
in parallel, a minimum stream of the 1,3-bis(methylthio)-1-propanol is supplied to the reacting of the methyl mercaptan with the acrolein.

6. The method according to claim 1 , wherein, if the acrolein is present in excess with respect to the methyl mercaptan, intermediately stored 1,3-bis(methylthio)-1-propanol is supplied to the reacting of the methyl mercaptan with the acrolein and is reacted with an excess acrolein to obtain the 3-methylthiopropionaldehyde.

7. The method according to claim 1 , wherein a molar amount of 1,3-bis(methylthio)-1-propanol supplied is at least as large as an amount of an excess acrolein.

8. The method according to claim 6 , wherein unreacted 1,3-bis(methylthio)-1-propanol is recovered.

9. The method according to claim 8 , wherein the 1,3-bis(methylthio)-1-propanol recovered is intermediately stored.

10. The method according to claim 8 , wherein, if the acrolein is present in excess with respect to the methyl mercaptan, a stream with an excess acrolein is branched off before the reacting to obtain the 3-methylthiopropionaldehyde and is reacted with the unreacted 1,3-bis(methylthio)-1-propanol separated from a product mixture to obtain the 3-methylthiopropionaldehyde.

11. The method according to claim 8 , wherein equal amounts of the unreacted 1,3-bis(methylthio)-1-propanol separated from a product mixture and the acrolein are reacted to obtain the 3-methylthiopropionaldhyde.

12. A method for storing methyl mercaptan and/or 3-methylthiopropionaldehyde, the method comprising:
storing the methyl mercaptan and/or 3-methylthiopropionaldehyde in form of 1,3-bis(methylthio)-1-propanol,
wherein the 1,3-bis(methylthio)-1-propanol originates from and/or is supplied to a process for continuously preparing the 3-methylthiopropionaldehyde,
wherein the process comprises:
reacting methyl mercaptan with acrolein to obtain the 3-methylthiopropionaldehyde,
wherein deviations in the stoichiometry of the methyl mercaptan to the acrolein in the reacting to obtain the 3-methylthiopropionaldehyde are compensated for by supplying or forming the 1,3-bis(methylthio)-1-propanol, and
wherein:
if the methyl mercaptan is present in excess with respect to the acrolein, an excess methyl mercaptan is converted to the 1,3-bis(methylthio)-1-propanol with the 3-methylthiopropionaldehyde, wherein the 1,3-bis(methylthio)-1-propanol formed is intermediately stored,
or
if the acrolein is present in excess with respect to the methyl mercaptan, the 1,3-bis(methylthio)-1-propanol is supplied during the reacting of the methyl mercaptan with the acrolein, wherein a molar amount of intermediately stored 1,3-bis(methylthio)-1-propanol to be supplied is at least as large as an amount of excess acrolein.

Assignees

• Evonik Operations Gmbh

Inventors

• Rautenberg Stephan
• Ceylan Sascha
• Koerfer Martin
• Hierold Judith
• Jakob Harald
• Kaiser Christian
• Malzkorn Rainer
• Merker Thorsten
• Nordschild Anja

Classifications

• C07C319/14

  of sulfides · CPC title

• C07C323/22

  containing thio groups and doubly-bound oxygen atoms bound to the same carbon skeleton · CPC title

• C07C319/18 Primary

  by addition of thiols to unsaturated compounds · CPC title

• C07C323/12

  the carbon skeleton being acyclic and saturated · CPC title