Process for continuously preparing methyl mercaptan from carbon compounds, sulfur and hydrogen

Patent metadata

Field	Value
Publication number	US-9745262-B2
Application number	US-83701710-A
Country	US
Kind code	B2
Filing date	Jul 15, 2010
Priority date	Jul 20, 2009
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

The invention relates to a process for continuously preparing methyl mercaptan by reacting a mixture comprising carbon compounds with sulfur and hydrogen, wherein the carbon disulfide and hydrogen sulfide compounds which form are subsequently converted to methyl mercaptan.

First claim

The invention claimed is:

1. A process for preparing methyl mercaptan, comprising the steps of
a) hydrogenating carbon disulfide and
b) reacting the hydrogen sulfide, which is contained in the reaction mixture formed the reactions before, with at least one of the compounds selected from the group consisting of alcohols, ethers, and aldehydes, in the presence of a metal oxide catalyst, wherein hydrogen is only added if required,
wherein said process is preceded by the reaction of carbon compounds or hydrocarbons with sulfur to give carbon disulfide and the formation of carbon disulfide is effected in the presence of a catalyst based on a Co—Ni system or an H-ZSM-5-zeolite.

2. The process as claimed in claim 1 , wherein the methyl mercaptan is removed from the reaction mixture that is formed in the hydrogenation of the carbon disulfide.

3. The process as claimed in claim 1 , wherein the carbon disulfide is converted at a reaction pressure of at least 5 bar and a temperature of at least 200° C.

4. The process as claimed in claim 1 , wherein the hydrogen sulfide is reacted with methanol.

5. The process as claimed in claim 1 , wherein the molar CS 2 /H 2 /H 2 S ratio after the hydrogenation of the carbon disulfide ranges from 1:1:1 to 1:10:10.

6. The process of claim 5 , wherein said molar CS 2 /H 2 /H 2 S ratio ranges from 1:1:1 to 1:5:10.

7. The process as claimed in claim 1 , wherein the hydrocarbons or carbon compounds originate from off-gas streams from processes for generating energy or chemical products.

8. The process as claimed in claim 1 , wherein the hydrocarbons or carbon compounds originate from the workup of processes for oxidizing hydrocarbons and for synthesizing nitrogen and sulfur compounds.

9. The process as claimed in claim 1 , wherein the hydrocarbons or carbon compounds originate from biological metabolism processes.

10. The process as claimed in claim 1 , wherein the carbon disulfide is formed in the presence of liquid or gaseous sulfur, in a one-stage or multistage non-catalyzed homogeneous reaction or using a catalyst.

11. The process as claimed in claim 1 , wherein, after removal of the methyl mercaptan, unconverted gaseous feed-stocks and by-products are removed and recycled into the process.

12. The process as claimed in claim 1 , wherein the total amount of the hydrogen sulfide is adjusted by varying the carbon-hydrogen ratio of the compounds present in the reaction mixture or of the H 2 content in the reaction gas fed to the process, and by varying one or more of the process parameters selected from the group of: residence time, reaction temperature and reaction pressure.

13. The process as claimed in claim 1 , wherein reactive distillations, bubble column reactors, fixed bed reactors, trickle bed reactors, staged reactors or tube bundle reactors are used for the catalyzed conversion to methyl mercaptan.

14. The process as claimed in claim 1 , wherein the reaction of the hydrocarbons with sulfur and the hydrogenation of the carbon disulfide formed to methyl mercaptan are performed in one reaction apparatus.

15. The process as claimed in claim 1 , wherein the reaction mixture which arises in the formation of carbon disulfide is supplied directly with no drop in a second process step tier hydrogenation of the carbon disulfide.

16. The process as claimed in claim 1 , wherein the metal oxide catalyst is an alkali metal tungstate, alkali metal molybdate, or alkali metal molybdate comprising transition metal oxides or sulfides as promoters.

17. The process as claimed in claim 16 , wherein at least one of the promoters selected from the group of oxides or sulfides of chromium, iron, cobalt, manganese and rhenium is present in the alkali metal tungstates, alkali metal molybdates or halogenated alkali metal tungstates or alkali metal molybdates.

18. The process as claimed in claim 1 , wherein the metal oxide catalyst comprises molybdates or tungstates comprising transition metal and alkali metal oxides or sulfides as promoters.

19. The process as claimed in claim 1 , wherein the metal oxide catalyst is a supported catalyst, which comprises oxidic molybdenum and potassium compounds, where Mo and K may be present in one compound, and which comprise at least one active oxidic compound of the general formula A x O y , A is one or more element from the iron or manganese group and x and y are each integers from 1 to 7.

20. The process of claim 19 , wherein A is one or more elements selected from the group consisting of Co, Mn, and Re.

21. The process as claimed in claim 1 , wherein molybdate- or tungstate-containing catalysts are used, which comprise transition metal and alkali metal oxides or sulfide as promoters.

22. The process as claimed in claim 1 , wherein the hydrogenation of carbon disulfide is effected in the presence of a catalyst.

23. The process as claimed in claim 22 , wherein the catalyst is an alkali metal molybdate or alkali metal tungstate.

24. The process of claim 1 , wherein the at least one of the compounds reacted with the hydrogen sulfide is selected from the group consisting of methanol, dimethyl ether, and formaldehyde.

25. The process of claim 1 , which results in the formation of methyl mercaptan with a selectivity of up to 98 percent.

Assignees

• Barth Jan-Olaf
• Weckbecker Christoph
• Redlingshoefer Hubert
• Lercher Johannes A
• Kaufmann Christoph
• Evonik Degussa Gmbh

Inventors

• Barth Jan-Olaf
• Weckbecker Christoph
• Redlingshoefer Hubert
• Lercher Johannes A
• Kaufmann Christoph

Classifications

• C01B17/161

  Preparation from elemental sulfur · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C07C319/02 Primary

  of thiols · CPC title

• C07C321/04

  of an acyclic saturated carbon skeleton · CPC title

• C07C319/08

  by replacement of hydroxy groups or etherified or esterified hydroxy groups · CPC title