Synthesis of hetero ionic compounds using dialkylcarbonate quaternization
Methods of preparing hetero ionic complexes, and ionic liquids from bisulfate salts of heteroatomic compounds using dialkylcarbonates as a primary quaternizing reactant are disclosed. Also disclosed are methods of making electrochemical cells comprising the ionic liquids, and an electrochemical cell comprising an alkaline electrolyte and a hetero ionic complex additive.
1. A method for preparing an ionic liquid comprising:
(1) reacting a heteroatomic compound with dialkylcarbonate to produce an alkylcarbonate salt of the heteroatomic compound;
(2) acidifying the alkylcarbonate salt with a sulfate-containing acid to produce a bisulfate salt of the heteroatomic compound; and
(3) converting the bisulfate salt of the heteroatomic compound to an ionic liquid comprising an alkyl-heteroatomic cation and an anion.
2. The method as claimed in claim 1 , wherein converting the bisulfate salt of the heteroatomic compound is carried out by either:
(a) reacting the bisulfate salt of the heteroatomic compound with a sodium salt to produce an ionic liquid comprising the cation of the alkyl-heteroatomic compound and the anion of the sodium salt; or
(b) contacting the bisulfate salt of the heteroatomic compound with a strong anion exchange resin containing the anion to produce an ionic liquid comprising the cation of the alkyl-heteroatomic compound and the anion.
3. The method of claim 1 , wherein the heteroatomic compound has the formula hetero-R—X, wherein R is selected from the group consisting of hydrogen, substituted and unsubstituted C1-C20 alkyl, substituted and unsubstituted aralkyl, X is a heteroatom selected from the group consisting of N, O, P, S, and mixtures thereof, which can be linear or can form a hetero or heteroaromatic ring, or bicyclic ring, with the proviso that hetero-R—X cannot form a linear amine or an imidazole group.
4. The method of claim 3 , wherein R is hydrogen.
5. The method of claim 1 , wherein the dialkylcarbonate contains two alkyl groups, each alkyl group being the same or different and being selected from the group consisting of substituted and unsubstituted C1-C20 alkyl, substituted and unsubstituted aralkyl, and mixtures thereof.
6. The method of claim 5 , wherein the alkyl groups are methyl.
7. The method of claim 1 , wherein acidifying comprises reacting the alkylcarbonate salt with sulfuric acid.
8. The method of claim 2 , wherein reacting the bisulfate salt of the heteroatomic compound with a sodium salt is performed in a mixture of alcohol and water.
9. The method of claim 8 , wherein the alcohol is selected from the group consisting of ethanol, a mixture of about 90% ethanol, 5% isopropanol, and 5% methanol, methanol, tetrahydrofuran, and mixtures thereof.
10. The method of claim 2 , wherein the anion exchange resin is a crosslinked polystyrene polymer comprising divinylbenzene (DVB) units in an amount of from about 2.5 to about 30% by weight, based on the weight of the resin, wherein the resin comprises the anion.
11. The method of claim 10 , wherein the anion is selected from the group consisting of halophosphates, hexafluorophosphate, alkylphosphates, arylphosphates, nitrate, sulfate, bisulfate, carbonates, alkyl carbonates, alkylsulfates, arylsulfates, perfluorinated alkyl- and arylsulfates, sulfonate, alkylsulfonates, arylsulfonates, perfluorinated alkyl- and arylsulfonates, trifluoromethylsulfonate, tosylate, perchlorate, tetrachloroaluminate, heptachlorodialuminate, tetrafluoroborate, alkylborates, arylborates, amides, perfluorinated amides, dicyanamide, saccharinate, thiocyanate, carboxylates, acetates, trifluoroacetate, bis(perfluoroalkylsulfonyl)amide, chloride (Cl—), hydroxide (OH—), hexafluorophosphate (PF6 ∘ -), iodide, other halides, tetrafluoroborate, bis(trifluoromethylsulfonyl)imide (C2F6NO4S2-), trifluoromethanesulfonate (CF3SO3-; TfO—), dicyanamide (N(CN)2-; dca), benzoate, acesulfame, saccharinate, methanesulfonate, and mixtures thereof.
12. The method of claim 10 , wherein the anion is hydroxide.
13. The method of claim 11 , wherein the anion is methyl carbonate.
14. The method of claim 1 , wherein the heteroatomic compound is 1,4, diazabicyclo[2,2,2]octane.
15. The method of claim 1 , wherein reacting the heteroatomic compound with dialkylcarbonate to produce an alkylcarbonate salt of the heteroatomic compound proceeds according to the following reaction:
wherein Hetero-R—X is the heteroatomic compound; R, R′, and R″ are the same or different and are selected from the group consisting of hydrogen, substituted and unsubstituted C1-C20 alkyl, substituted and unsubstituted aralkyl, and mixtures thereof; X is a heteroatom selected from the group consisting of N, O, P, S, and mixtures thereof,
wherein Hetero-R—X can be linear or can form a hetero or heteroaromatic ring, or bicyclic ring, with the proviso that Hetero-R—X cannot form a linear tertiary amine or an imidazole group.
16. The method of claim 1 , wherein acidifying alkylcarbonate salt with a sulfate-containing acid to produce a bisulfate salt of the heteroatomic compound proceeds according to the following reaction:
wherein Hetero-R—X is the heteroatomic compound; R, R′, and R″ are the same or different and are selected from the group consisting of hydrogen, substituted and unsubstituted C1-C20 alkyl, substituted and unsubstituted aralkyl, and mixtures thereof; X is a heteroatom selected from the group consisting of N, O, P, S, and mixtures thereof,
wherein Hetero-R—X can be linear or can form a hetero or heteroaromatic ring, or bicyclic ring, with the proviso that Hetero-R—X cannot form a linear tertiary amine or an imidazole group.
17. The method of claim 2 , wherein converting the bisulfate salt of the heteroatomic compound to an ionic liquid comprising an alkyl-heteroatomic cation and an anion proceeds according to the following reaction:
wherein Hetero-R—X is the heteroatomic compound; R and R′ are the same or different and are selected from the group consisting of hydrogen, substituted and unsubstituted C1-C20 alkyl, substituted and unsubstituted aralkyl, and mixtures thereof; X is a heteroatom selected from the group consisting of N, O, P, S, and mixtures thereof; M selected from the group consisting of an alkali metal, an alkaline earth metal, ammonium (NH4+), and mixtures thereof, and A is an anion,
wherein Hetero-R—X can be linear or can form a hetero or heteroaromatic ring, or bicyclic ring, with the proviso that Hetero-R—X cannot form a linear tertiary amine or an imidazole group.
18. The method of claim 1 , wherein the alkyl-hetero-atomic cation is 1-methyl-4-aza-1-azoniabicyclo[2,2,2]octane.
19. The method of claim 18 , wherein the anion is hydroxide.
20. The method of claim 18 , wherein the anion is alkyl carbonate.
21. The method of claim 20 , wherein the alkyl carbonate is methyl carbonate.
22. The method of claim 14 , wherein the alkyl-hetero-atomic cation is 1-methyl-4-aza-1-azoniabicyclo[2,2,2]octane.
23. The method of claim 22 , wherein the anion is hydroxide.
24. The method of claim 22 , wherein the anion is alkyl carbonate.