Method for the manufacture of cyclododecasulfur
The present invention relates to a method for the manufacture of cyclododecasulfur, a cyclic sulfur allotrope wherein the number of sulfur (S) atoms in the allotrope's homocyclic ring is 12. The method includes reacting a metallasulfur derivative with an oxidizing agent in a reaction zone to form a cyclododecasulfur-containing reaction mixture.
1. A method for the manufacture of cyclododecasulfur, comprising reacting a metallasulfur derivative with an oxidizing agent in a reaction zone to form a cyclododecasulfur-containing reaction mixture containing cyclododecasulfur, wherein the oxidizing agent does not add sulfur from its composition to the cyclododecasulfur being produced in the process.
2. The method of claim 1 , wherein the metallasulfur derivative is characterized by the formula:
wherein
L is a monodentate or polydentate ligand species which may be the same or different when x>1;
x is the total number of ligand species and is from 0 to 6 inclusive;
M is a metal atom;
y is the total number of metal atoms and is from 1 to 4 inclusive;
S is a sulfur atom;
z is the number of sulfur atoms, and is from 1 to 12 inclusive;
u represents the charge of the metallasulfur derivative and may be from −6 to +6 inclusive;
v is the number of metallasulfur derivative units in an oligomeric or polymeric structure;
I is an ionic atom or group and may be cationic or anionic;
and w is the number of cationic or anionic atoms or groups, as required to provide charge neutrality.
3. The method of claim 1 , wherein the oxidizing agent is characterized by the formula:
X—X′
wherein X and X′ are the same or different and are selected from the group consisting of halogens and pseudohalogens.
4. The method of claim 1 , wherein the oxidizing agent comprises one or more of SO 2 Cl 2 and SO 2 Br 2 .
5. The method of claim 1 wherein the oxidizing agent comprises one or more of O 2 , H 2 O 2 , an alkyl peroxide, and an acyl peroxide.
6. The method of claim 1 , wherein the stoichiometric ratio of the oxidizing agent to the metallasulfur derivative is selected so that less than one equivalent of the oxidizing agent is present for every two M-S bonds in the metallasulfur derivative.
7. The method of claim 3 , wherein X and X′ are one or more of chlorine and bromine.
8. The method of claim 1 , further comprising a step of reacting elemental sulfur with a sulfur templating agent to form the metallasulfur derivative prior to the step of reacting the metallasulfur derivative with the oxidizing agent.
9. The method of claim 8 , wherein the reacting the elemental sulfur with a sulfur templating agent to form the metallasulfur derivative is carried out in the presence of water.
10. The method of claim 1 , further comprising a step of isolating the cyclododecasulfur from the cyclododecasulfur-containing reaction mixture.
11. The method of claim 10 , wherein the step of isolating the cyclododecasulfur from the cyclododecasulfur-containing reaction mixture comprises one or more steps chosen from dissolving, heat treating, drying, acid treating, solvent washing, crystallizing, and sedimentation.
12. The method of claim 10 , wherein the step of isolating the cyclododecasulfur comprises treating the cyclododecasulfur with a solvent for the cyclododecasulfur to form a dissolution liquor.
13. The method of claim 10 , further comprising removing metal and metal-containing compounds from the cyclododecasulfur by sedimentation of the metal and the metal-containing compounds.
14. The method of claim 1 , further comprising isolating cyclododecasulfur by heating a cyclododecasulfur-containing mixture in the presence of a solvent to decompose and dissolve in the solvent impurities that are present.
15. The method of claim 1 , further comprising isolating cyclododecasulfur by treating a cyclododecasulfur-containing mixture with an acid to remove any metal or metal-containing compounds that are present.
16. The method of claim 12 , further comprising crystallizing cyclododecasulfur from the dissolution liquor.
17. A method for the manufacture of cyclododecasulfur, the method comprising:
(i) reacting cyclooctasulfur, tetramethylethylenediamine, and zinc to form a tetramethylethylenediamine/Zn(S 6 ) complex; and
(ii) reacting the complex with an oxidizing agent.
18. The method of claim 17 , wherein the step of reacting the cyclooctasulfur, the tetramethylethylenediamine, and the zinc to form a tetramethylethylene-diamine/Zn(S 6 ) complex is carried out in the presence of water.