Process for the preparation of organic disulfides
AssigneeBASF SE
InventorsWerner Hesse, Hans-Josef Sterzel, Christian Tragut
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Abstract
The invention relates to a process for the preparation of organic disulfides by oxidation of mercaptans with sulfur dissolved in an organic disulfide using an amine as catalyst, where the mercaptans are used as “crude mercaptan stream” from a reaction of alcohols with hydrogen sulfide over a catalyst suitable for mercaptan synthesis. Furthermore, the invention relates to the use of the organic disulfides for the preparation of alkanesulfonic acids.
Claims31
A continuous process for the preparation of an organic disulfide comprising:
- oxidizing a mercaptan with sulfur dissolved in an organic disulfide in the presence of an amine catalyst,
- wherein said mercaptan is present in a crude mercaptan stream, which is obtained from a reaction of an alcohol with hydrogen sulfide in the presence of a catalyst suitable for mercaptan synthesis, and
- wherein said amine is a primary, secondary, or tertiary amine having from 6 to 60 carbon atoms, and which has a boiling point above the boiling point of said organic disulfide, and a water solubility of less than 0.5 g/l.
A process comprising:
- (a) reacting an alkanol with hydrogen sulfide over a catalyst to form a crude mercaptan stream comprising mercaptan, water, and hydrogen sulfide;
- (b) reacting the crude mercaptan stream with sulfur dissolved in an organic disulfide in the presence of an amine catalyst in a reaction column, and returning any low-boiling components which form to (a), wherein said amine catalyst is a primary, secondary, or tertiary amine having from 6 to 60 carbon atoms, a boiling point above the boiling point of said organic disulfide, and a water solubility of less than 0.5 g/l;
- (c) phase separating the resulting mixture comprising aqueous phase, which is removed from the system, and organosulfur phase;
- (d) purifying the organosulfur phase, which optionally comprises low-boiling components, the desired organic disulfide, polysulfides, amine and other by-products, wherein the organic disulfide is removed, any low-boiling components which form are returned to (a), and polysulfides which form and amine are returned to (b), with addition of sulfur and optionally amine;
- wherein the phase separation and the removal from the system of the aqueous phase in (c) takes place immediately following (a) or (b).
A continuous process for the preparation of an organic disulfide comprising:
- (a) reacting an alkanol with hydrogen sulfide over a catalyst to form a crude mercaptan stream comprising mercaptan, water, and hydrogen sulfide;
- (b) reacting the crude mercaptan stream with sulfur dissolved in an organic disulfide in the presence of an amine catalyst, which is a liquid or solid and has a boiling point above the boiling point of the organic disulfide and a water solubility of less than 0.5%, in a reaction column, where low-boiling components which form are returned to (a);
- (c) phase separating the resulting mixture comprising an aqueous phase, which is removed from the system, and an organosulfur phase;
- (d) purifying the organosulfur phase, which optionally comprises low-boiling components, the desired organic disulfide, polysulfides, amine and other by-products by distillation under reduced pressure, wherein the organic disulfide is removed, any low-boiling components which form are returned to (a), and polysulfides which form and amine are returned to (b), with addition of sulfur and optionally amine;
- wherein the phase separation and the removal from the system of the aqueous phase in (c) takes place immediately following (a) or (b).
Dependencies are inferred from the claim text.