Method for preparing 3-methylthiopropionaldehyde

Patent metadata

Field	Value
Publication number	US-2020299232-A1
Application number	US-201716076247-A
Country	US
Kind code	A1
Filing date	Mar 14, 2017
Priority date	Feb 15, 2016
Publication date	Sep 24, 2020
Grant date	—

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

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, 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.

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 the reacting of the methyl mercaptan with the acrolein.

6 : The method according to claim 1 , wherein the 1,3-bis(methylthio)-1-propanol formed is intermediately stored.

7 : The method according to claim 6 , 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.

8 : The method according to claim 6 , 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.

9 : 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.

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

11 : The method according to claim 10 , wherein the 1,3-bis(methylthio)-1-propanol recovered is intermediately stored.

12 : The method according to claim 10 , 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.

13 : The method according to claim 10 , 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.

14 : 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.

15 : The method according to claim 14 ,
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 a 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, 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.

Assignees

• Evonik Operations Gmbh

Inventors

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

Classifications

• C07C319/18 Primary

  by addition of thiols to unsaturated compounds · CPC title

• C07C323/22

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

• C07C319/14

  of sulfides · CPC title