Process for the production of low flammability electrolyte solvents
The invention provides a method for producing electrolyte solvent, the method comprising reacting a glycol with a disilazane in the presence of a catalyst for a time and at a temperature to silylate the glycol, separating the catalyst from the silylated glycol, removing unreacted silazane; and purifying the silylated glycol.
1. A continuous method for producing battery grade electrolyte solvent, the method comprising:
a. reacting a glycol with a disilazane in the presence of a catalyst in a reactor for a time and at a temperature to silylate the glycol;
b. separating the catalyst from the silylated glycol wherein the catalyst remains in the reactor;
c. removing unreacted silazane; and
d. purifying the silylated glycol, wherein the method is conducted without an inert atmosphere.
2. The method as recited in claim 1 wherein the reacting step comprises combining the glycol with the disilazane and the catalyst in a reactor.
3. The method as recited in claim 1 wherein the time is selected from between about 2 and about 6 hours.
4. The method as recited in claim 1 wherein the temperature is selected from between about 30° C. and about 70° C.
5. The method as recited in claim 1 wherein the catalyst is a solid catalyst selected from the group consisting of Amberlyst, Nafion, Montmorillonite, and combinations thereof.
6. The method as recited in claim 1 wherein the catalyst is solid and the catalyst is separated from the silylated glycol by simple particle filtration.
7. The method as recited in claim 2 wherein the unreacted silazane is returned to the reactor.
8. The method as recited in claim 1 wherein the silylated glycol is purified in a single fractional distillation.
9. The method as recited in claim 1 wherein the silylated glycol is more than 99.5 percent pure.
10. The method as recited in claim 1 wherein the glycol is a polyethylene glycol selected from the group consisting of alkyl ethers of HO(CH2CH2O) x OAlkyl, where x=2-5, Alkyl=group of 1-6 carbon atoms.
11. The method as recited in claim 1 wherein no solvent is utilized.
12. The method as recited in claim 1 wherein the only waste product is ammonia.
13. The method as recited in claim 1 wherein the glycol is 2-(2-methoxyethoxy)ethanol and the silylated glycol is 2,2-dimethyl-3,6,9-trioxa-2-siladecane.
14. The method as recited in claim 1 wherein the glycol is 2-(2-(2-methoxyethoxy)ethoxy)ethanol and the silylated glycol is 2,2-dimethyl-3,6,9,12-tetraoxa-2-silatridecane.
15. The method as recited in claim 1 wherein the disilazane is a hexa-substituted disilazane selected from the group consisting of hexamethyldisilazane, 1,3-diethyl-1,1,3,3-tetramethyldisilazane, 1,3-diallyl-1,1,3,3-tetramethyldisilazane, 1,3-diphenyl-1,1,3,3-tetramethyldisilazane, and combinations thereof.
16. The method as recited in claim 1 wherein the catalyst is immobilized within the reactor.
17. The method as recited in claim 1 wherein the catalyst is present in a weight percent of between about 0.5 to about 30.