Hydrophobic liquid salts, the preparation thereof and their appliction in electrochemistry

• US 5,683,832 A
• Filed: 12/18/1995
• Issued: 11/04/1997
• Est. Priority Date: 12/21/1994
• Status: Expired due to Term

• Current Assignee: Centre National De La Recherche Scientifique, Hydro-Quebec (Province of Québec)
• Original Assignee: Asulab SA (The Swatch Group AG)
• Inventors: Dias, Ana-Paula, Bonhote, Pierre
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/574,317
• Time in Patent Office: 687 Days
• Field of Search: 429/111, 429/194, 252/62.2, 548/335.1
• US Class Current: 429/111
• CPC Class Codes: C07D 233/56 with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms
• CPC Class Codes: H01G 9/2004 characterised by the electrolyte, e.g. comprising an organic electrolyte
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells

Abstract

Hydrophobic liquid salts of the general formula ##STR1## in which R₁ and R₃ are the same or different and each represent a straight or branched chain alkyl radical, a fluoroalkyl radical or an alkoxyalkyl radical of 1 to 8 carbon atoms; and R₂, R₄, and R₅ are the same or different and each represent a hydrogen atom or an alkyl radical with 1 to 3 carbon atoms.

The invention has applications as an electrolyte solvent in electrochemical photovoltaic cells.

Claims

1. Hydrophobic liquid salts of the general formula ##STR4## in which R₁ and R₃ are the same or different and each represent a straight or branched alkyl radical, a fluoroalkyl radical, or an alkoxyalkyl radical of 1 to 8 carbon atoms;

and R₂, R₄, and R₅ are the same or different and each represent a hydrogen atom or an alkyl radical with 1 to 3 carbon atoms.

2. Hydrophobic liquid salts according to claim 1, characterised in that R₁ or R₃ represent a methyl, ethyl, butyl, isobutyl, octyl, methoxyethyl, or 2,2,2-trifluoroethyl radical and R₂, R₄, and R₅ represent hydrogen or a methyl or ethyl radical.

3. A hydrophobic liquid salt according to claim 1, characterised in that it corresponds to methyl-1-butyl-3-imidazolium-bis-triflylamide.

4. A hydrophobic liquid salt according to claim 1, characterised in that it corresponds to methyl-1-ethyl-3-imidazolium-bis-triflylamide.

5. A hydrophobic liquid salt according to claim 1, characterised in that it corresponds to ethyl-1-butyl-3-imidazolium-bis-triflylamide.

6. A process for the preparation of a hydrophobic liquid salt of the general formula ##STR5## in which R₁ and R₃ are the same or different and each represent a straight or branched alkyl radical a fluoroalkyl radical, or an alkoxyallcyl radical of 1 to 8 carbon atoms;

and R₂, R₄ and R₅ are the same or different and each represent a hydrogen atom or an alkyl radical with 1 to 3 carbon atoms;

said process being characterized in that an imidazolium halide substituted by R₁, R₂, R₃, R₄, and R₅ is caused to react in aqueous medium with an alkali metal-bis-triflylamide, and in that the product obtained is separated by decantation.

7. A process of preparation according to claim 6, characterised in that the halide is a bromide or an iodide and the alkali metal is lithium.

8. An electrolytic composition containing as an aprotic polar solvent a hydrophobic liquid salt of the general formula ##STR6## in which R₁ represents an alkyl radical having 1 to 5 carbon atoms, R₃ represents a straight or branched alkyl radical, a fluoroalkyl radical, or an alkoxyalkyl radical having 1 to 8 carbon atoms;

and R₂, R₄, and R₅ each represent a hydrogen atom or an alkyl radical having 1 to 3 carbon atoms.

9. An electrochemical photovoltaic cell comprising an electrolytic composition according to claim 8 containing the iodo/tri-iodide redox couple.