Flame Retardants For Battery Electrolytes

Abstract

This invention provides nonaqueous electrolyte solutions for lithium batteries. The nonaqueous electrolyte solutions comprise a liquid electrolyte medium; a lithium-containing salt; and at least one oxygen-containing brominated flame retardant.

Claims

1. A nonaqueous electrolyte solution for a lithium battery, which solution comprises i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) at least one oxygen-containing brominated flame retardant A) selected from a) a brominated noncyclic ether, b) a brominated cyclic diether, c) a brominated noncyclic carbonate having two hydrocarbyl groups in which at least one hydrocarbyl group has at least one unsaturated carbon-carbon bond, or has aromatic character, and d) a brominated cyclic carbonate having a carbonate ring, which carbonate ring has at least one unsaturated carbon-carbon bond; or B) selected from the group consisting of 1-bromo-2-methoxyethane, 1-bromo-3-methoxypropane, 2-bromo-1,1-dimethoxyethane, 2-bromo-1,4-dimethoxybenzene, 1-bromo-2-(methoxymethoxy)ethane, 1-bromovinyl ethyl ether, 1,2-dibromo-3-methoxy-1-propene, 1,2-dibromo-3-ethoxy-1-propene, di(ethylene glycol) dibromovinyl ether, 4-bromo-1,3-dioxolane, 2-bromomethyl-1,3-dioxolane, 2-dibromomethyl-1,3-dioxolane, 2-tribromomethyl-1,3-dioxolane, 2,2-bis(bromomethyl)-1,3-dioxolane, 2-(bromomethyl)-1,4-dioxane, 5,5-bis(bromomethyl)-2-methyl-1,3-dioxane, 5,5-bis(bromomethyl)-2-ethyl-1,3-dioxane, 3-bromo-2-propenyl methyl carbonate, 2,3-dibromo-2-propenyl methyl carbonate, 2,3,3-tribromo-2-propenyl methyl carbonate, 3-bromo-2-propenyl ethyl carbonate, 2,4-dibromophenyl methyl carbonate, bis(2,3-dibromo-2-propenyl) carbonate, 4-bromo-1,3-dioxol-2-one, 4,5-dibromo-1,3-dioxol-2-one, 4-bromomethyl-1,3-dioxol-2-one, 4,4-bis(bromomethyl)-1,3-dioxol-2-one, and 4,5-bis(bromomethyl)-1,3-dioxol-2-one.

2. A solution as in claim 1 wherein the brominated flame retardant of A) has a boiling point of about 95° C. or higher, or wherein the brominated flame retardant has a boiling point in the range of about 75° C. to about 450° C.

3. (canceled)

4. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant of A) has about three to about ten carbon atoms, one to about five bromine atoms, and/or a bromine content of about 35 wt % or more relative to the total weight of the oxygen-containing brominated flame retardant, or is a brominated cyclic diether or a brominated cyclic carbonate which has a 5-membered or 6-membered ring, and optionally has about three to about ten carbon atoms, one to about five bromine atoms, and/or a bromine content of about 35 wt % or more relative to the total weight of the oxygen-containing brominated flame retardant.

5. (canceled)

6. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant of A) is a brominated noncyclic ether which has about three to about ten carbon atoms and a bromine content of about 30 wt % or more relative to the total weight of the oxygen-containing brominated flame retardant; a brominated cyclic diether which has about three to about eight carbon atoms and one to about three bromine atoms; a brominated noncyclic carbonate which has about four to about eight carbon atoms and one to about four bromine atoms; or a brominated cyclic carbonate which has about three to about ten carbon atoms, one to about five bromine atoms, and a bromine content of about 40 wt % or more relative to the total weight of the oxygen-containing brominated flame retardant.

7. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant of A) is a brominated cyclic diether containing two or more bromine atoms wherein all of the bromine atoms are in one or more hydrocarbyl groups, or all of the bromine atoms are bound to carbon atoms of the ring; a brominated noncyclic carbonate which has at least one alkyl, alkenyl, aryl, or ar-alkyl group; or a brominated cyclic carbonate containing two or more bromine atoms wherein all of the bromine atoms are in one or more hydrocarbyl groups bound to the carbonate ring, or all of the bromine atoms are bound to carbon atoms of the carbonate ring.

8. A solution as in claim 7 wherein the oxygen-containing brominated flame retardant of A) is a brominated cyclic diether containing two or more bromine atoms and having two or more hydrocarbyl groups bound to the carbonate ring, and wherein the bromine atoms are in different hydrocarbyl groups; a brominated noncyclic carbonate having hydrocarbyl groups which are selected from methyl, ethyl, propenyl, and phenyl groups; or a brominated cyclic carbonate containing two or more bromine atoms and having two or more hydrocarbyl groups bound to the carbonate ring, wherein the bromine atoms are in different hydrocarbyl groups.

9. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant of A) is a brominated cyclic diether having two or more hydrocarbyl groups bound to the carbonate ring, which hydrocarbyl groups are methyl groups; or a brominated cyclic carbonate having two or more hydrocarbyl groups bound to the carbonate ring, which hydrocarbyl groups are methyl groups; or a brominated noncyclic carbonate in which one hydrocarbyl group is a methyl group; or 2,4-dibromophenyl methyl carbonate or 2,3-dibromo-2-propenyl methyl carbonate.

10-11. (canceled)

12. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant is in an amount of about 10 wt % or more bromine relative to the total weight of the solution.

13. A solution as in claim 1 wherein the liquid electrolyte medium is ethylene carbonate, ethyl methyl carbonate, or a mixture thereof, and/or wherein the lithium-containing salt is lithium hexafluorophosphate, lithium di(fluoro)(oxolato)borate, or lithium bis(oxolato)borate.

14. A solution as in claim 1 further comprising at least one electrochemical additive selected from: a) unsaturated cyclic carbonates containing three to about six carbon atoms, b) fluorine-containing saturated cyclic carbonates containing three to about five carbon atoms and one to about four fluorine atoms, c) tris(trihydrocarbylsilyl) phosphites containing three to about nine carbon atoms, d) trihydrocarbyl phosphates containing three to about twelve carbon atoms, e) cyclic sultones containing three to about eight carbon atoms, f) saturated cyclic hydrocarbyl sulfites having a 5-membered or 6-membered ring and containing two to about six carbon atoms, g) saturated cyclic hydrocarbyl sulfates having a 5-membered or 6-membered ring and containing two to about six carbon atoms, h) cyclic dioxadithio polyoxide compounds having a 6-membered, 7-membered, or 8-membered ring and containing two to about six carbon atoms, i) another lithium-containing salt, and j) mixtures of any two or more of the foregoing.

15. A solution as in claim 14 wherein the electrochemical additive is selected from: a) unsaturated cyclic carbonates containing three to about four carbon atoms, b) fluorine-containing saturated cyclic carbonates containing three to about four carbon atoms and one to about two fluorine atoms, c) tris(trihydrocarbylsilyl) phosphites containing three to about six carbon atoms, d) trihydrocarbyl phosphates containing three to about nine carbon atoms, e) cyclic sultones containing three to about four carbon atoms, f) saturated cyclic hydrocarbyl sulfites having a 5-membered ring and containing two to about four carbon atoms, g) saturated cyclic hydrocarbyl sulfates having a 5-membered ring and containing two to about four carbon atoms, h) cyclic dioxadithio polyoxide compounds having a 6-membered or 7-membered ring and containing two to about four carbon atoms, i) another lithium-containing salt, and j) mixtures of any two or more of the foregoing.

16. A solution as in claim 14 wherein the electrochemical additive is selected from: a) an unsaturated cyclic carbonate in an amount of about 0.5 wt % to about 12 wt %, relative to the total weight of the nonaqueous electrolyte solution, b) a fluorine-containing saturated cyclic carbonate in an amount of about 0.5 wt % to about 8 wt %, relative to the total weight of the nonaqueous electrolyte solution, c) a tris(trihydrocarbylsilyl) phosphite in an amount of about 0.1 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, d) a trihydrocarbyl phosphate in an amount of about 0.5 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, e) a cyclic sultone in an amount of about 0.25 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, f) a saturated cyclic hydrocarbyl sulfite in an amount of about 0.5 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, g) a saturated cyclic hydrocarbyl sulfate in an amount of about 0.25 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, h) a cyclic dioxadithio polyoxide compound in an amount of about 0.5 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, i) another lithium-containing salt in an amount of about 0.5 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution, and j) mixtures of any two or more of the foregoing.

17. A solution as in claim 14 wherein the electrochemical additive is a saturated cyclic hydrocarbyl sulfate, a cyclic sultone, a tris(trihydrocarbylsilyl) phosphite, or another lithium-containing salt.

18. A solution as in claim 14 wherein the electrochemical additive is a saturated cyclic hydrocarbyl sulfate in an amount of about 1 wt % to about 4 wt %, a cyclic sultone in an amount of about 0.5 wt % to about 4 wt %, a tris(trihydrocarbylsilyl) phosphite in an amount of about 0.15 wt % to about 1 wt %, or another lithium-containing salt in an amount of about 1 wt % to about 4 wt %, each relative to the total weight of the nonaqueous electrolyte solution; or 1,3,2-dioxathiolane 2,2-dioxide, 1-propene-1,3-sultone, 1-propane-1,3-sultone, tris(trimethylsilyl)phosphite, or lithium bis(oxolato)borate.

19. (canceled)

20. A solution as in claim 18 wherein each electrochemical additive is not used with other electrochemical additives.

21. A solution as in claim 14 wherein the electrochemical additive is selected from vinylene carbonate, 4-fluoro-ethylene carbonate, tris(trimethylsilyl)phosphite, triallyl phosphate, 1-propane-1,3-sultone, 1-propene-1,3-sultone, ethylene sulfite, 1,3,2-dioxathiolane 2,2-dioxide, 1,5,2,4-dioxadithiane 2,2,4,4-tetroxide, lithium di(fluoro)(oxolato)borate, lithium bis(oxolato)borate, and mixtures of any two or more of these.

22. A solution as in claim 21 wherein the electrochemical additive is selected from: vinylene carbonate in an amount of about 0.5 wt % to about 3 wt %, relative to the total weight of the nonaqueous electrolyte solution; vinylene carbonate in an amount of about 8 wt % to about 11 wt %, relative to the total weight of the nonaqueous electrolyte solution; 4-fluoro-ethylene carbonate in an amount of about 1.5 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution; tris(trimethylsilyl)phosphite in an amount of about 0.2 wt % to about 3 wt %, relative to the total weight of the nonaqueous electrolyte solution; triallyl phosphate in an amount of about 1 wt % to about 5 wt %, relative to the total weight of the nonaqueous electrolyte solution; 1-propane-1,3-sultone or 1-propene-1,3-sultone in an amount of about 0.5 wt % to about 4 wt %, relative to the total weight of the nonaqueous electrolyte solution; 1,3,2-dioxathiolane, 2-oxide in an amount of about 1 wt % to about 4 wt %, relative to the total weight of the nonaqueous electrolyte solution; 1,3,2-dioxathiolane 2,2-dioxide in an amount of about 1 wt % to about 4 wt %, relative to the total weight of the nonaqueous electrolyte solution; 1,5,2,4-dioxadithiane 2,2,4,4-tetroxide in an amount of about 1 wt % to about 4 wt %, relative to the total weight of the nonaqueous electrolyte solution; lithium bis(oxolato)borate in an amount of about 1 wt % to about 4 wt %, relative to the total weight of the nonaqueous electrolyte solution; and mixtures of any two or more of these.

23. A solution as in claim 21 wherein the electrochemical additive is selected from 1-propane-1,3-sultone, 1-propene-1,3-sultone, 1,3,2-dioxathiolane 2,2-dioxide, tris(trimethylsilyl)phosphite, and lithium bis(oxolato)borate; or selected from 1-propane-1,3-sultone in an amount of about 0.5 wt % to about 4 wt %, 1-propene-1,3-sultone in an amount of about 0.5 wt % to about 4 wt %, 1,3,2-dioxathiolane 2,2-dioxide, in an amount of about 1 wt % to about 4 wt %, and lithium bis(oxolato)borate in an amount of about 1 wt % to about 4 wt %, each relative to the total weight of the nonaqueous electrolyte solution.

24. (canceled)

25. A solution as in claim 23 wherein each electrochemical additive is not used with other electrochemical additives.

26. A nonaqueous lithium battery comprising a positive electrode, a negative electrode, and a nonaqueous electrolyte solution as in claim 1.

27. (canceled)

28. A solution as in claim 1 wherein the oxygen-containing brominated flame retardant of B) is selected from the group consisting of 1-bromo-2-methoxy ethane, 1-bromo-3-methoxypropane, 2-bromo-1,1-dimethoxyethane, 2-bromo-1,4-dimethoxybenzene, 1-bromo-2-(methoxymethoxy)ethane, 1-bromovinyl ethyl ether, 1,2-dibromo-3-methoxy-1-propene, 1,2-dibromo-3-ethoxy-1-propene, and di(ethylene glycol) dibromovinyl ether; or selected from the group consisting of 4-bromo-1,3-dioxolane, 2-bromomethyl-1,3-dioxolane, 2-dibromomethyl-1,3-dioxolane, 2-tribromomethyl-1,3-dioxolane, 2,2-bix(bromomethyl)-1,3-dioxolane, 2-(bromomethyl)-1,4-dioxane, 5,5-bis(bromomethyl)-2-methyl-1,3-dioxane, and 5,5-bis(bromomethyl)-2-ethyl-1,3-dioxane; or selected from the group consisting of 3-bromo-2-propenyl methyl carbonate, 2,3-dibromo-2-propenyl methyl carbonate, 2,3,3-tribromo-2-propenyl methyl carbonate, 3-bromo-2-propenyl ethyl carbonate, 2,4-dibromophenyl methyl carbonate, and bis(2,3-dibromo-2-propenyl) carbonate; or selected from the group consisting of 4-bromo-1,3-dioxol-2-one, 4,5-dibromo-1,3-dioxol-2-one, 4-bromomethyl-1,3-dioxol-2-one, 4,4-bis(bromomethyl)-1,3-dioxol-2-one, and 4,5-bis(bromomethyl)-1,3-dioxol-2-one.

29-34. (canceled)

35. A process for producing a nonaqueous electrolyte solution for a lithium battery, which process comprises combining components comprising: i) a liquid electrolyte medium; ii) a lithium-containing salt; and iii) at least one oxygen-containing brominated flame retardant selected from a) a brominated noncyclic ether, b) a brominated cyclic diether, c) a brominated noncyclic carbonate having two hydrocarbyl groups in which at least one hydrocarbyl group has at least one unsaturated carbon-carbon bond, or has aromatic character, and d) a brominated cyclic carbonate having a carbonate ring, which carbonate ring has at least one unsaturated carbon-carbon bond.

36. A process as in claim 35 wherein the components further comprise at least one electrochemical additive selected from: a) unsaturated cyclic carbonates containing three to about six carbon atoms, b) fluorine-containing saturated cyclic carbonates containing three to about five carbon atoms and one to about four fluorine atoms, c) tris(trihydrocarbylsilyl) phosphites containing three to about nine carbon atoms, d) trihydrocarbyl phosphates containing three to about twelve carbon atoms, e) cyclic sultones containing three to about eight carbon atoms, f) saturated cyclic hydrocarbyl sulfites having a 5-membered or 6-membered ring and containing two to about six carbon atoms, g) saturated cyclic hydrocarbyl sulfates having a 5-membered or 6-membered ring and containing two to about six carbon atoms, h) cyclic dioxadithio polyoxide compounds having a 6-membered, 7-membered, or 8-membered ring and containing two to about six carbon atoms, i) another lithium-containing salt, and j) mixtures of any two or more of the foregoing.

37. (canceled)

38. A process as in claim 35 wherein the brominated flame retardant is of B), and wherein the components further comprise at least one electrochemical additive selected from vinylene carbonate, 4-fluoro-ethylene carbonate, tris(trimethylsilyl)phosphite, triallyl phosphate, 1-propane-1,3-sultone, 1-propene-1,3-sultone, ethylene sulfite, 1,3,2-dioxathiolane 2,2-dioxide, 1,5,2,4-dioxadithiane 2,2,4,4-tetroxide, lithium di(fluoro)(oxolato)borate, lithium bis(oxolato)borate, and mixtures of any two or more of these.

39. Each of the following molecules separately, as a new composition of matter: 1,2-dibromo-3-ethoxy-1-propene; di(ethylene glycol) dibromovinyl ether; 3-bromo-2-propenyl methyl carbonate; 3-bromo-2-propenyl ethyl carbonate; 2,3-dibromo-2-propenyl methyl carbonate; 2,3,3-tribromo-2-propenyl methyl carbonate; 2,4-dibromophenyl methyl carbonate; 5,5-bis(bromomethyl)-2-methyl-1,3-dioxane; 5,5-bis(bromomethyl)-2-ethyl-1,3-dioxane; 4-bromo-1,3-dioxolane.

40-48. (canceled)

Description

EXAMPLE 1

[0075] Various nonaqueous electrolyte solutions containing different oxygen-containing brominated flame retardants, prepared as described above, were subjected to the modified UL-94 test described above. Results are summarized in Table 1 below; as noted above, the reported numbers are an average value from three runs.

TABLE-US-00001 TABLE 1 Flame retardant Bromine wt % wt % Time to Flame retardant in soln. in soln. Result extinguish 2,4-dibromophenyl methyl carbonate 30 15.6 flame retardant 22 s 2,3-dibromo-2-propenyl methyl carbonate 20 11.7 flame retardant 36 s 2-bromomethyl-1,3-dioxolane 20 9.6 self-extinguish. 62 s 1-bromo-2-methoxyethane 30 17.2 flame retardant 22 s 2-bromo-1,1-dimethoxyethane 30 14.2 flame retardant 12 s 1-bromo-2-(methoxymethoxy)ethane 30 14.2 flame retardant 18 s 3-bromo-2-propenyl methyl carbonate 25 10.26 flame retardant 26 s

EXAMPLE 2

[0076] Tests of some flame retardants in coin cells were also carried out. Coin cells were assembled using nonaqueous electrolyte solutions containing the desired amount of flame retardant. The coin cells were then subjected to electrochemical cycling of CCCV charging to 4.2 V at C/5, with a current cutoff of C/50 in the CV portion, and CC discharge at C/5 to 3.0 V.

[0077] One sample was a nonaqueous electrolyte solution without a flame retardant, and contained 1.2 M LiPF.sub.6 in ethylene carbonate/ethyl methyl carbonate (wt ratio 3:7). The rest of the samples contained the desired amount of flame retardant in the electrolyte solution; some solutions also contained an additive in addition to the flame retardant. Results are summarized in Table 2 below; the error range in the Coulombic efficiencies is about 0.5% to about ±1.0%.

TABLE-US-00002 TABLE 2 Flame retardant Bromine Coulombic efficiency Chemical Name in soln. in soln. 1st cycle 10th cycle Electrolyte soln..sup.1 0 0 81.8% 99.6% 2-bromo-1,1-dimethoxyethane.sup.2 8 wt % 3.79 wt % 37.6% 79.5% 1-bromovinyl ethyl ether.sup.2 8 wt % 4.24 wt % 29.9% 80.7% 1-bromo-2-(methoxymethoxy)ethane.sup.2 8 wt % 3.79 wt % 34.2% 91.9% 2,4-dibromophenyl methyl carbonate.sup.3 8 wt % 4.2 wt % 46.6% 92.5% 4-bromo-1,3-dioxol-2-one.sup.3 8 wt % 3.9 wt % 60.5% 89.6% 2-bromo-1,4-dimethoxybenzene.sup.3 8 wt % 3 wt % 0.4% 38.1% 2-bromomethyl-1,3-dioxolane.sup.3 8 wt % 3.8 wt % 31.8% 84.0% 3-bromo-2-propenyl methyl carbonate.sup.2 8 wt % 3.28 wt % 70.0% 98.9% .sup.1Comparative run. .sup.2Data is from single best-performing cell. .sup.3Data is an average from multiple cells (“multiple cells” usually menas two or three cells).

EXAMPLE 3

Synthesis of 1,2-dibromo-3-ethoxy-1-propene

[0078] Aqueous NaOH (50 wt %, 17.5 g), 2,3-dibromoallyl alcohol (21.6 g, 0.1 mol), tetrabutylammonium bromide (1.0 g), and bromoethane (21.8 g, 0.2 mol) were charged to a 500-mL jacketed round bottom flask and this mixture was stirred while heating to 40° C., and then heated at 40° C. for 6 hours. After cooling the mixture to room temperature, the reaction mass was diluted with ethyl ether (120 mL) and washed with deionized water (100 mL). After drying over MgSO.sub.4 and then filtering to remove solids, the solvent was removed on a rotary evaporator. The product was further dried under high vacuum to give 1,2-dibromo-3-ethoxy-1-propene as a clear liquid (19.54 g; 79% yield).

EXAMPLE 4

Synthesis of di(ethylene glycol) dibromovinyl ether

[0079] Dichloromethane (100 mL) and di(ethylene glycol) divinyl ether (31.6 g, 0.2 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred in ice cold water. an ice cold water bath. To this mixture Br.sub.2 (64 g, 0.4 mol) was added to the flask slowly using a peristaltic pump. After all of the Br.sub.2 had been added, the reaction mixture was stirred for 2 hours while allowing the reaction mixture to reach room temperature. The reaction flask was then was placed in an ice cold water bath, and triethylamine (50 g, 0.494 mol) was added to the flask dropwise from an addition funnel. After all of the triethylamine had been added, the reaction mixture was stirred for 4 hours while allowing the reaction mixture to reach room temperature. The mixture was filtered to remove the solid that had formed, and the residual solution was collected in a 250-mL round flask. The solvent was removed from residual solution in the round flask, and then the residual liquid in the round flask was passed through a silica gel column to obtain di(ethylene glycol) dibromovinyl ether (35.5 g; 56.2% yield).

EXAMPLE 5

Synthesis of 5,5-bis(bromomethyl)-2-methyl-1,3-dioxane

[0080] Toluene (100 mL), p-toluenesulphonic acid monohydrate (0.5 g), and 2,2-bis(bromomethyl)-1,3-propanediol (52.4 g, 0.2 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred at room temperature. To this mixture acetaldehyde (12 g, 0.27 mol) was added. The reaction mixture was heated to reflux, kept at reflux for 2 hours, and then cooled to room temperature and washed with dilute aqueous NaOH (30 mL) and followed by water (30 mL). The mixture was allowed to separate into phases; the organic phase was further treated. The solvent was removed from the organic phase, and then the residual liquid from the organic phase was purified by vacuum distillation to obtain 5,5-bis(bromomethyl)-2-methyl-1,3-dioxane (54 g; 99% yield).

EXAMPLE 6

Synthesis of 5,5-bis(bromomethyl)-2-ethyl-1,3-dioxane

[0081] Toluene (150 mL), p-toluenesulphonic acid monohydrate (1.0 g), and 2,2-bis(bromomethyl)-1,3-propanediol (104.8 g, 0.4 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred at room temperature. To this mixture propionaldehyde (29.0 g, 0.5 mol) was added. The reaction mixture was heated to reflux, kept at reflux for 2 hours, and then cooled to room temperature and washed with dilute aqueous NaOH (200 mL) and followed by water (100 mL). The mixture was allowed to separate into phases; the organic phase was further treated. The solvent was removed from the organic phase, and then the residual liquid from the organic phase was purified by vacuum distillation to obtain 5,5-bis(bromomethyl)-2-ethyl-1,3-dioxane (120.8 g; 99% yield).

EXAMPLE 7

Synthesis of 3-bromo-2-propenyl methyl carbonate (bromoallyl methyl carbonate)

[0082] Dichloromethane (150 mL) and allyl methyl carbonate (34.8 g, 0.3 mol) were introduced to a 500-mL round bottom flask and then magnetically stirred in an ice cold water bath. To this mixture Br.sub.2 (48 g, 0.3 mol) was added slowly using a peristaltic pump. After all of the Br.sub.2 had been added, the reaction mixture was stirred for 2 hours while allowing the reaction mixture to reach room temperature. The reaction flask was then was placed in an ice cold water bath, and triethylamine (40 g, 0.395 mol) was added to the flask dropwise from an addition funnel. After all of the triethylamine had been added, the reaction mixture was stirred for 4 hours while allowing the reaction mixture to reach room temperature. The mixture was filtered to remove the solid that had formed, and the residual solution was collected in a 500-mL round flask. The solvent was removed from residual solution in the round flask, and then the residual liquid in the round flask was passed through the silica gel column and purified by vacuum distillation to obtain bromoallyl methyl carbonate (32.3 g; 55.2% yield).

EXAMPLE 8

Synthesis of 3-bromo-2-propenyl ethyl carbonate (bromoallyl ethyl carbonate)

[0083] Dichloromethane (100 mL) and allyl ethyl carbonate (26 g, 0.2 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred in an ice cold water bath. To this mixture Br.sub.2 (32 g, 0.2 mol) was added slowly using a peristaltic pump. After all of the Br.sub.2 had been added, the reaction mixture was stirred for 2 hours while allowing the reaction mixture to reach room temperature. The reaction flask was then was placed in an ice cold water bath, and triethylamine (22.3 g, 0.22 mol) was added to the flask dropwise from an addition funnel. After all of the triethylamine had been added, the reaction mixture was stirred for 4 hours while allowing the reaction mixture to reach room temperature. The mixture was filtered to remove the solid that had formed, and the residual solution was collected in a 250-mL round flask. The solvent was removed from residual solution in the round flask, and then the residual liquid in the round flask was passed through the silica gel column and purified by vacuum distillation to obtain bromoallyl ethyl carbonate (19.7 g; 47% yield).

EXAMPLE 9

Synthesis of 2,3-dibromo-2-propenyl methyl carbonate

[0084] Dichloromethane (75 g) and 2,3-dibromo-2-propen-1-ol (21.6 g, 0.1 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred in a cold water bath. To this mixture triethylamine (11.3 g, 0.11 mol) was added slowly, and then methyl chloroformate (10.4 g, 0.11 mol) was added dropwise over 1 hour using a syringe pump. After all of the methyl chloroformate had been added, the reaction mixture was stirred for 1 hour while allowing the reaction mixture to reach room temperature and then water was added to quench the reaction. Aqueous HCl (10 wt %) was added to adjust the pH to 1. The mixture was allowed to separate into phases; the organic phase was further treated. The organic phase was washed with water (25 mL), dilute aqueous NaOH (25 mL) and more water (25 mL). The solvent was removed from the organic phase, and then the residual liquid from the organic phase was purified by vacuum distillation to obtain 2,3-dibromo-2-propenyl methyl carbonate (16.4 g; 60% yield).

EXAMPLE 10

Synthesis of 2, 4-Dibromophenyl methyl carbonate

[0085] Dichloromethane (100 g) and 2,4-dibromophenol (25.2 g, 0.1 mol) were introduced to a 250-mL round bottom flask and then magnetically stirred in a cold water bath. To this mixture triethylamine (11.3 g, 0.11 mol) was added slowly, and then methyl chloroformate (10.4 g, 0.11 mol) was added dropwise over 1 hour using a syringe pump. After all of the methyl chloroformate had been added, the temperature of the reaction mixture was raised to 35° C., and the reaction mixture was stirred at 35° C. for 1 hour, and then water was added to quench the reaction. Aqueous HCl (10 wt %) was added to adjust the pH to 1. The mixture was allowed to separate into phases; the organic phase was further treated. The organic phase was washed with water (25 mL), dilute aqueous NaOH (25 mL) and more water (25 mL). The solvent was removed from the organic phase, and then the residual liquid from the organic phase was purified by vacuum distillation to obtain 2,3-dibromo-2-propenyl methyl carbonate (30.7 g; 99% yield).

[0086] Components referred to by chemical name or formula anywhere in the specification or claims hereof, whether referred to in the singular or plural, are identified as they exist prior to coming into contact with another substance referred to by chemical name or chemical type (e.g., another component, a solvent, or etc.). It matters not what chemical changes, transformations and/or reactions, if any, take place in the resulting mixture or solution as such changes, transformations, and/or reactions are the natural result of bringing the specified components together under the conditions called for pursuant to this disclosure. Thus the components are identified as ingredients to be brought together in connection with performing a desired operation or in forming a desired composition. Also, even though the claims hereinafter may refer to substances, components and/or ingredients in the present tense (“comprises”, “is”, etc.), the reference is to the substance, component or ingredient as it existed at the time just before it was first contacted, blended or mixed with one or more other substances, components and/or ingredients in accordance with the present disclosure. The fact that a substance, component or ingredient may have lost its original identity through a chemical reaction or transformation during the course of contacting, blending or mixing operations, if conducted in accordance with this disclosure and with ordinary skill of a chemist, is thus of no practical concern.

[0087] The invention may comprise, consist, or consist essentially of the materials and/or procedures recited herein.

[0088] As used herein, the term “about” modifying the quantity of an ingredient in the compositions of the invention or employed in the methods of the invention refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term about also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term “about”, the claims include equivalents to the quantities.

[0089] Except as may be expressly otherwise indicated, the article “a” or “an” if and as used herein is not intended to limit, and should not be construed as limiting, the description or a claim to a single element to which the article refers. Rather, the article “a” or “an” if and as used herein is intended to cover one or more such elements, unless the text expressly indicates otherwise.

[0090] This invention is susceptible to considerable variation in its practice. Therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.