Oxidation of mercaptoethanol
View Patent ↗A process for preparing dihydroxyethylene disulfide by reacting mercaptoethanol with oxygen, in which mercaptoethanol is reacted with oxygen or an oxygenous gas in the presence of ammonia and/or amines using copper salts or manganese salts.
1. A process for preparing dihydroxyethylene disulfide by reacting mercaptoethanol with oxygen, comprising the step of reacting mercaptoethanol with oxygen or an oxygenous gas in the presence of ammonia and/or amines using copper salts or manganese salts.
2. The process as claimed in claim 1 , wherein the copper salts used are copper(II) salts.
3. The process as claimed in claim 1 , wherein the manganese salts used are manganese (II) salts.
4. The process as claimed in claim 2 , wherein the copper (II) salt is copper acetate.
5. The process as claimed in claim 3 , wherein the manganese (II) salt is manganese acetate.
6. The process as claimed in claim 1 , wherein mercaptoethanol is initially charged and oxygen is metered into the initial charge.
7. The process as claimed in claim 1 , wherein the reaction is carried out under a partial oxygen pressure of from 0.5 to 5 bar.
8. The process as claimed in claim 4 , wherein the reaction is carried out under an elevated oxygen pressure of 1-5 bar.
9. The process as claimed in claim 8 characterized in that the reaction is carried out at a pressure of 1-2.5 bar.
10. The process as claimed in claim 4 , wherein the reaction is carried out under a constant oxygen pressure.
11. The process as claimed in claim 4 , wherein a stoichiometric amount of oxygen is used for the reaction.
12. The process as claimed in claim 4 , wherein aqueous ammonia is used.
13. The process as claimed in claim 4 , wherein the metal salt used is dissolved in ammonia or in the amine.
14. The process as claimed in claim 4 , wherein the reaction is carried out at from 20 to 60° C.
15. The process as claimed in claim 14 , characterized in that the reaction is carried out at from 35 to 45° C.
16. The process as claimed in claim 4 , wherein the reaction is carried out in the absence of organic solvents.
17. The process as claimed in claim 4 , wherein the reaction is carried out in an aqueous medium.
18. The process as claimed in claim 17 , wherein the reaction is used in the presence of 10-70% by weight of water based on the total amount of the substances used.