Catalyst for oxidation reactions, a method for its preparation and the use thereof
The present invention relates to a catalyst for oxidation reactions, particularly for oxidation of mercaptan dialkyldisulfides and/or dialklypolysulfides with oxygen to alkanesulfonic acids.
1. A catalyst according to general formula (I):
Q a [M b (VO 4 ) c ] a− (I),
wherein
Q is a quaternary ammonium cation of the general formula (II)
R 1 R 2 R 3 R 4 N + (II),
wherein each of R 1 , R 2 , R 3 and R 4 is independently of each other a saturated C 1 to C 20 alkyl radical or an aromatic C 5 or C 6 radical with the proviso that at least one of R 1 , R 2 , R 3 and R 4 is a saturated C 4 to C 20 alkyl group,
M is at least one metal selected from the group consisting of alkali metals, alkaline earth metals, group III metals and transition metals,
V denotes vanadium,
O denotes oxygen,
a is an integer from 1 to 3,
b is the integer 1 or 2, and
c is the integer 1 or 2.
2. The catalyst according to claim 1 , wherein Q is a quaternary ammonium cation according to the general formula (III):
(C n H 2n+1 ) o (CH 3 ) 4−o N + (III),
wherein
n is an integer from 4 to 18, and
o is an integer from 1 to 4.
3. The catalyst according to claim 2 , wherein Q is selected from the group of quaternary ammonium cations consisting of (C 4 H 9 ) 4 N + , (C 4 H 9 ) 3 (CH 3 )N + , (C 4 H 9 ) 2 (CH 3 ) 2 N + , (C 4 H 9 )(CH 3 ) 3 N + , (C 8 H 17 ) 4 N + , (C 8 H 17 ) 3 (CH 3 )N + , (C 8 H 17 ) 2 (CH 3 ) 2 N + , (C 8 H 17 )(CH 3 ) 3 N + , (C 12 H 25 ) 4 N + , (C 12 H 25 ) 3 (CH 3 )N − , (C 12 H 25 ) 2 (CH 3 ) 2 N + , (C 12 H 25 )(CH 3 ) 3 N + , (C 16 H 33 ) 4 N + , (C 16 H 33 ) 3 (CH 3 )N + , (C 16 H 33 ) 2 (CH 3 ) 2 N + , (C 16 H 33 )(CH 3 ) 3 N + , (C 18 H 37 ) 4 N + , (C 18 H 27 ) 3 (CH 3 )N + , (C 18 H 37 ) 2 (CH 3 ) 2 N + , (C 18 H 37 )(CH 3 ) 3 N + , ((C 18 H 37 ) 75% (C 16 H 33 ) 25% ) 2 (CH 3 ) 2 N + and combinations thereof.
4. The catalyst according to claim 3 , wherein Q is (C 16 H 33 ) 4 N + , (C 16 H 33 ) 3 (CH 3 )N + , (C 16 H 33 ) 2 (CH 3 ) 2 N + , or (C 16 H 33 )(CH 3 ) 3 N + or combinations thereof.
5. The catalyst according to claim 1 , wherein the metal M is selected from the group consisting of Mg, Co, Cu, Fe, Ba, Zr and combinations thereof.
6. The catalyst according to claim 5 , wherein the metal M is Mg.
7. The catalyst according to claim 5 , wherein a is 1, b is 1 and c is 1.
8. The catalyst according to claim 6 , wherein the catalyst is a compound of the formula C 16 H 33 (CH 3 ) 3 )N + [MgVO 4 ] − .
9. The catalyst according to claim 1 that is suitable for oxidation reactions.
10. A method for the production of a catalyst according to claim 1 , which comprises:
a) providing a solution of a salt of the metal M in nitric acid,
b) adding a salt of the quaternary ammonium cation Q to the solution obtained in a),
c) adding a solution of a salt of an orthovanadate to the solution obtained in b),
d) stirring the solution obtained in c),
e) concentrating the solution of d) under reduced pressure to give a catalytically active mass, and
f) drying the catalytically active mass obtained in e).
11. The method according to claim 10 , wherein the sequence of b) and c) is exchanged.
12. A method for oxidation of a sulfur containing hydrocarbon compound comprising contacting a catalyst according to claim 1 with at least one sulfur containing hydrocarbon compound.
13. The method according to claim 12 that comprises
oxidation of alkylmercaptan to dialkyldisulfide and/or at least one alkanesulfonic acid with oxygen or hydrogen peroxide as an oxidizing agent in the presence or absence of nitric acid, or
oxidation of dialkyldisulfide to alkanesulfonic acid with oxygen or hydrogen peroxide as oxidizing agent in the presence or absence of nitric acid or the oxidation of dialkylpolysulfide to alkanesulfonic acid with oxygen or hydrogen peroxide as oxidizing agent in the presence or absence of nitric acid.
14. The method according to claim 13 , that comprises oxidation of methylmercaptan to dimethyldisulfide and/or methanesulfonic acid with oxygen or hydrogen peroxide as oxidizing agent in the presence or absence of nitric acid, or
oxidation of dimethyldisulfide to methanesulfonic acid with oxygen or hydrogen peroxide as oxidizing agent in the presence or absence of nitric acid or the oxidation of dimethylpolysulfide to methanesulfonic acid with oxygen or hydrogen peroxide as oxidizing agent in the presence or absence of nitric acid.
15. A process for the preparation of alkanesulfonic acid comprising:
a) providing a solution comprising a sulfur containing hydrocarbon compound and a catalyst according to claim 1 in an organic solvent,
b) introducing oxygen or hydrogen peroxide into a reaction system, and
c) stirring the resulting mixture.
16. The process according to claim 15 , wherein water is added in an amount which is sufficient to give the desired alkanesulfonic acid.
17. The process according to claim 15 , wherein the sulfur containing hydrocarbon compound is methylmercaptan or dimethyldisulfide.
18. The process according to claim 15 , wherein the organic solvent is selected from the group consisting of optionally substituted alkanes, optionally substituted aromatic hydrocarbons, esters, ethers, ketones, alcohols, carboxylic acids, nitriles amides, sulfones, sulfoxides, alkanesulfonic acids and combinations thereof.
19. The process according to claim 15 , wherein the process is performed at a pressure of from 10 bar to 120 bar.
20. The process according to claim 15 , wherein the process is performed at a temperature of from 40° C. to 150° C.
21. A catalyst according to general formula (I):
Q a [M b (VO 4 ) c ] a− (I),
wherein
Q is a quaternary ammonium cation of the general formula (II)
R 1 R 2 R 3 R 4 N 1 (II),
wherein each of R 1 , R 2 , R 3 and R 4 is independently of each other a saturated C 1 to C 20 alkyl radical or an aromatic C 5 or C 6 radical with the proviso that at least one of R 1 , R 2 , R 3 and R 4 is a saturated C 4 to C 20 alkyl group,
M is at least one metal selected from the group consisting Mg, Co, Cu, Fe, Ba, Zr and combinations thereof,
V denotes vanadium,
O denotes oxygen,
a is an integer from 1 to 3,
b is the integer 1 or 2, and
c is the integer 1 or 2.
22. The catalyst according to claim 21 , wherein a is 1, b is 1 and c is 1.