Removing impurities from polythiophene
Impurities are removed from polythiophene by mixing a composition comprising polythiophene, water and an organic liquid at a temperature at which the organic liquid dissolves the polythiophene; allowing an aqueous phase to separate from an organic phase and recovering organic phase; adding water to recovered organic phase and mixing the resulting composition at a temperature at which the organic liquid dissolves the polythiophene; allowing an aqueous phase to separate from an organic phase and recovering organic phase; and allowing polythiophene solid to precipitate from recovered organic phase.
1. A method for removing impurities from polythiophene, comprising:
(a) mixing a composition comprising the polythiophene, water and an organic liquid at a temperature at which the organic liquid dissolves the polythiophene;
(b) in the composition formed in (a), allowing an aqueous phase to separate from an organic phase and recovering organic phase;
(c) adding water to recovered organic phase and mixing the resulting composition at a temperature at which the organic liquid dissolves the polythiophene;
(d) in the composition formed in (c), allowing an aqueous phase to separate from an organic phase and recovering organic phase; and
(e) allowing polythiophene solid to precipitate from recovered organic phase.
2. A method according to claim 1 , further comprising separating the polythiophene solid from organic liquid by filtration and drying the filtered polythiophene solid.
3. A method according to claim 1 , wherein said organic liquid is chlorobenzene.
4. A method according to claim 3 , wherein said temperature at which the organic liquid dissolves the polythiophene is at least 50° C.
5. A method according to claim 1 , wherein said polythiophene has the following formula:
where each R, which may be the same or different, is an alkyl or substituted alkyl having from 1 to 25 carbon atoms.
6. A method according to claim 5 , wherein said polythiophene is
7. A method according to claim 1 , wherein (c) and (d) are conducted more than one time.
8. A method according to claim 7 , wherein, during at least one occurrance of (c), the water added to the organic phase contains a base.
9. A method according to claim 8 , wherein the base is ammonium hydroxide.
10. A method according to claim 1 , wherein the polythiophene solid is allowed to precipitate from recovered organic phase by lowering the temperature of the organic phase to a temperature at which the organic liquid does not dissolve the polythiophene.
11. A method according to claim 1 , wherein the polythiophene solid is allowed to precipitate from recovered organic phase by mixing the recovered organic phase with a second organic liquid, such that the resulting composition does not dissolve the polythiophene.
12. A method according to claim 11 , wherein said second organic liquid is methanol.
13. A method according to claim 3 , wherein the polythiophene solid is allowed to precipitate from recovered organic phase by mixing the recovered organic phase, which is at a temperature of at least 50° C., with methanol.
14. A method according to claim 13 , wherein said recovered organic phase is added to the methanol over about 15 to 20 minutes.
15. A method according to claim 13 , wherein said methanol is at room temperature.
16. A method for removing impurities from polythiophene, comprising:
(a) mixing a composition comprising the polythiophene, water and an organic liquid at a temperature at which the organic liquid dissolves the polythiophene;
(b) in the composition formed in (a), allowing an aqueous phase to separate from an organic phase and recovering organic phase;
(c) adding water to recovered organic phase and mixing the resulting composition at a temperature at which the organic liquid dissolves the polythiophene;
(d) in the composition formed in (c), allowing an aqueous phase to separate from an organic phase and recovering organic phase;
(e) using the organic phase recovered in (d), repeating (c) and (d) at least one time;
(f) adding a basic aqueous solution to organic phase recovered in (e) and mixing the resulting composition at a temperature at which the organic liquid dissolves the polythiophene;
(g) in the composition formed in (f), allowing an aqueous phase to separate from an organic phase and recovering organic phase;
(h) using the organic phase recovered in (g), repeating (c) and (d) at least one time; and
(i) allowing polythiophene solid to precipitate from organic phase recovered in (h).
17. A method according to claim 16 , wherein said basic aqueous solution contains ammonium hydroxide.
18. A method for preparing polythiophene, comprising:
(a) polymerizing thiophene monomer and/or an oligomer of thiophene monomer in an organic solvent in the presence of metal halide to form polythiophene;
(b) mixing a composition comprising polythiophene formed in (a), water and an organic liquid at a temperature at which the organic liquid dissolves the polythiophene;
(c) in the composition formed in (b), allowing an aqueous phase to separate from an organic phase and recovering organic phase;
(d) adding water to recovered organic phase and mixing the resulting composition at a temperature at which the organic liquid dissolves the polythiophene;
(e) in the composition formed in (d), allowing an aqueous phase to separate from an organic phase and recovering organic phase; and
(f) allowing polythiophene solid to precipitate from recovered organic phase.
19. A method according to claim 18 , wherein said metal halide is ferric chloride.
20. A method according to claim 18 , wherein the organic solvent in (a) and the organic liquid in (b) are both chlorobenzene.