Storage of 3-methylthiopropionaldehyde and methyl mercaptan
A compound, which is 1-(1,3-bis(methylthio)propoxy)-3-(methylthio)propan-1-ol, a composition containing the compound, a method for the preparation thereof, a method for preparing 3-methylthiopropionaldehyde by reacting 1-(1,3-bis(methylthio)propoxy)-3-(methylthio)propan-1-ol with acrolein, and also to the use of 1-(1,3-bis(methylthio)propoxy)-3-(methylthio)propan-1-ol or compositions containing the compound for the storage and/or transport of 3-methylthiopropionaldehyde and/or methyl mercaptan.
1. A method for preparing a compound of formula (I):
the method comprising:
a) bringing a composition comprising 3-methylthiopropionaldehyde into contact with a composition comprising methyl mercaptan, to obtain a composition comprising the compound of formula (I), wherein a molar ratio of 3-methylthiopropionaldehyde to methyl mercaptan in a) is between 2:1 and 4:1.
2. The method according to claim 1 , wherein a) is conducted at a temperature of not more than 70° C.
3. The method according to claim 1 , additionally comprising the step upstream of a) of
a′) bringing a composition comprising acrolein into contact with a composition comprising methyl mercaptan, to obtain a composition comprising 3-methylthiopropionaldehyde.
4. The method according to claim 1 , additionally comprising the step upstream and/or downstream of a) of
a″) bringing a composition comprising the compound of formula (I) into contact with acrolein, to obtain a composition comprising 3-methylthiopropionaldehyde.
5. The method according to claim 3 , wherein a) and/or a′) are carried out in the presence of at least one nitrogen-containing base as catalyst.
6. The method according to claim 5 , wherein the nitrogen-containing base is an unsubstituted or substituted N-heterocyclic compound or an amine of the formula NR 1 R 2 R 3 , wherein R 1 , R 2 and R 3 are either identical or different and are each independently of each other hydrogen, an alkyl residue having one to four carbon atoms or an arylalkyl residue having 7 to 14 carbon atoms, with the proviso that, if one of the residues R 1 , R 2 or R 3 is hydrogen, the two other residues are not hydrogen.
7. The method according to claim 3 , wherein step a) and/or step a′) are carried out in the presence of at least one acid.
8. A method for preparing 3-methylthiopropionaldehyde, comprising bringing a composition comprising a compound of formula (I) obtained by the method accoring to claim 1 , into contact with a composition comprising acrolein, to obtain a composition comprising 3-methylthiopropionaldehyde.
9. The method according to claim 8 , additionally comprising:
a′) bringing a composition comprising acrolein into contact with a composition comprising methyl mercaptan, to obtain a composition comprising 3-methylthiopropionaldehyde; or
a″) bringing a composition comprising the compound of formula (I) into contact with acrolein, to obtain a composition comprising 3-methylthiopropionaldehyde.
10. The method according to claim 1 , wherein a) is conducted at a temperature of not more than 25° C.
11. The method according to claim 1 , wherein a) is conducted at a temperature of not more than 15° C.
12. The method according to claim 1 , wherein the compound is at least one selected from the group consisting of:
1-(1R,3-bis(methylthio)propoxy)-3-(methylthio)propan-1R-ol,
1-(1R,3-bis(methylthio)propoxy)-3-(methylthio)propan-1S-ol,
1-(1S,3-bis(methylthio)propoxy)-3-(methylthio)propan-1R-ol, and
1-(1S,3-bis(methylthio)propoxy)-3-(methylthio)propan-1S-ol.