Method for preparing methyl mercaptan
View Patent ↗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 (H2); c) optionally recirculating said hydrogen sulphide (H 2 S) formed during step b) to step a); and d) recovering the methyl mercaptan.
1. A process for preparing methyl mercaptan, batchwise or continuously, said process comprising at least the following steps:
a) reacting at least one hydrocarbon charge in the presence of hydrogen sulphide (H 2 S) to form carbon disulphide (CS 2 ) and hydrogen (H 2 ), wherein the molar H 2 S/hydrocarbon charge ratio is between 0.5 and 10, endpoints included,
b) carrying out a 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) recovering the methyl mercaptan.
2. The process according to claim 1 , wherein the hydrocarbon charge is a hydrocarbon charge 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. The process according to claim 1 , wherein the hydrocarbon charge comprises at least one alkane.
4. The process according to claim 1 , wherein the hydrocarbon charge is methane.
5. The process according to claim 1 , wherein the hydrogen sulphide formed in step b) is recycled into step a).
6. The process according to claim 1 , wherein hydrogen is formed in step b) and is reacted with sulphur to form hydrogen sulphide.
7. The process according to claim 1 , wherein step a) is carried out at a reaction temperature between 500° C. and 1300° C.
8. The process according to claim 1 , wherein step b) is carried out at a reaction temperature between 100° C. and 400° C.
9. The process according to claim 1 , wherein the methyl mercaptan is reacted with sulphur to form dimethyl disulphide.
10. The process according to claim 1 , wherein the process is performed continuously.
11. The process according to claim 1 , wherein the hydrocarbon charge is in gaseous form.
12. The process according to claim 1 , wherein the hydrocarbon charge comprises at least one alkane selected from the group consisting of methane, ethane, propane and butane.
13. The process according to claim 1 , wherein the molar H 2 S/hydrocarbon charge ratio is between 1 and 3, endpoints included.
14. The process according to claim 1 , wherein step a) is carried out at a reaction temperature between 700° C. and 1100° C.
15. The process according to claim 1 , wherein step a) is carried out at a reaction temperature between 800° C. and 1000° C.
16. The process according to claim 1 , wherein step b) is carried out at a reaction temperature between 200° C. and 300° C.
17. The process according to claim 1 , wherein all of the hydrogen sulfide consumed in said process is produced in said process.
18. The process according to claim 1 , wherein hydrogen sulfide produced in said process is consumed in said process.
19. The process according to claim 1 , which produces 0.1 kg to 20 kg of methyl mercaptan per hour per liter of catalyst in step b).
20. The process according to claim 1 , conducted in the absence of a purification step between step a) and step b).
21. The process according to claim 1 , wherein the selectivity for methyl mercaptan is 100%.