Method for preparing methyl mercaptan
The present invention relates to a method for preparing methyl mercaptan, in batches or continuously, preferably continuously, said method including at least the following steps: a) reacting at least one hydrocarbon feedstock in the presence of hydrogen sulphide (H 2 S) and optionally sulphur (S) such as to form carbon disulphide (CS 2 ) and hydrogen (H 2 ); b) reacting said carbon disulphide (CS 2 ) by hydrogenation in the presence of said hydrogen (H 2 ) obtained in step a) such as to form methyl mercaptan (CH 3 SH), hydrogen sulphide (H 2 S) and possibly hydrogen (H 2 ); c) optionally recirculating said hydrogen sulphide (H 2 S) formed during step b) to step a); and d) recovering the methyl mercaptan.
1. Process for preparing methyl mercaptan, said process being batchwise or continuous and comprising at least the following steps:
a) reaction of at least one hydrocarbon charge in the presence of hydrogen sulphide (H 2 S) and optionally of sulphur (S) to form carbon disulphide (CS 2 ) and hydrogen (H 2 ),
b) hydrogenation reaction of said carbon disulphide (CS 2 ) in the presence of said hydrogen (H 2 ), both obtained in step a), to form methyl mercaptan (CH 3 SH), hydrogen sulphide (H 2 S) and optionally hydrogen (H 2 ),
c) optionally, recycling said hydrogen sulphide (H 2 S) formed in step b) to step a), and
d) recovery of the methyl mercaptan.
2. Process according to claim 1 , wherein the hydrocarbon charge is in gaseous, liquid or solid form, and comprises at least one hydrocarbon having a hydrocarbon chain in saturated or unsaturated linear, branched or cyclic form.
3. Process according to claim 1 , wherein the hydrocarbon charge comprises at least one alkane.
4. Process according to claim 1 , wherein the hydrocarbon charge is methane.
5. Process according to claim 1 , wherein the hydrogen sulphide formed in step b) is recycled into step a).
6. Process according to claim 1 , wherein the hydrogen optionally formed in step b) may be reacted with sulphur to form hydrogen sulphide.
7. Process according to claim 1 , wherein the molar H 2 S/hydrocarbon charge ratio is between 0 and about 100.
8. Process according to claim 1 , wherein the reaction temperature in step a) is between 500° C. and 1300° C.
9. Process according to claim 1 , wherein the reaction temperature in step b) is between 100° C. and 400° C.
10. Process according to claim 1 , wherein the methyl mercaptan is reacted with sulphur to form dimethyl disulphide.
11. Process according to claim 1 , wherein the process is a continuous process.
12. Process according to claim 2 , wherein the hydrocarbon charge is in gaseous or liquid form.
13. Process according to claim 2 , wherein the hydrocarbon charge is in gaseous form.
14. Process according to claim 3 , wherein the hydrocarbon charge is at least one of methane, ethane, propane and butane.
15. Process according to claim 7 , wherein the molar H 2 S/hydrocarbon charge ratio is between 0.5 and about 10.
16. Process according to claim 7 , wherein the molar H 2 S/hydrocarbon charge ratio is between 1 and about 3.
17. Process according to claim 8 , wherein the reaction temperature in step a) is between 700° C. and 1100° C.
18. Process according to claim 8 , wherein the reaction temperature in step a) is between 800° C. and 1000° C.
19. Process according to claim 9 , wherein the reaction temperature in step b) is between 200° C. and 300° C.