Ionic liquids and their use as solvents

• US 20040097755A1
• Filed: 07/07/2003
• Published: 05/20/2004
• Est. Priority Date: 09/27/2000
• Status: Active Grant

• Current Assignee: Scionix
• Original Assignee: Scionix
• Inventors: Abbott, Andrew P., Davies, David L., Tambyrajah, Vasuki, Rasheed, Raymond K., Capper, Glen
• Granted Patent: US 7,183,433 B2
• Time in Patent Office: Days
• US Class Current: 562/553
• CPC Class Codes: B01J 2231/125 Radical (co)polymerisation, e.g. mediators therefor
• CPC Class Codes: B01J 2231/4261 Heck-type, i.e. RY + C=C, in which R is aryl
• CPC Class Codes: B01J 31/006 comprising organic radicals, e.g. TEMPO
• CPC Class Codes: B01J 31/0249 Ureas (R2N-C(=O)-NR2)
• CPC Class Codes: B01J 31/0279 the cationic portion being acyclic or nitrogen being a substituent on a ring
• CPC Class Codes: B01J 31/0284 of an aromatic ring, e.g. pyridinium
• CPC Class Codes: B01J 31/04 containing carboxylic acids or their salts B01J31/0277 - B01J31/0298 take precedence; multi-metal carboxylate complexes like Pd (II) acetate, i.e. Pd3 (OAc) 6 or Cr(II)acetate, i.e. Cr2(OAc)4 B01J31/2226
• CPC Class Codes: C07C 275/02 Salts; Complexes; Addition compounds
• CPC Class Codes: C07C 41/30 by increasing the number of carbon atoms, e.g. by oligomerisation
• CPC Class Codes: C07C 43/215 having unsaturation outside the six-membered aromatic rings
• CPC Class Codes: C25D 3/02 from solutions C25D5/34 - C25D5/46 take precedence
• CPC Class Codes: C25F 3/16 Polishing
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids

Abstract

Ionic compounds with a freezing point of up to 100° C. are formed by the reaction of an one amine salt of formula (I) R¹R²R³R⁴N⁺X⁻, such as choline chloride with an organic compound (II) capable of forming a hydrogen bond with X; such as urea, wherein the molar ration of I to II is from 1:1.5 to 1:2.5. R¹, R², R³ and R⁴ may be H, optionally substituted C₁ to C₅ alkyl, optionally substituted C₆ to C₁₀ cycloalkyl, optionally substituted C₆ to C₁₂ aryl, optionally substituted C₇ to C₁₂ alkaryl, or R¹ and R² taken together may represent a C₄ to C₁₀ optionally substituted alkylene group, thereby forming with the N atom of formula I a 5 to 11-membered heterocyclic ring and all of R¹, R², R³ and R⁴ are not identical, X⁻ may be NO₃⁻, F, Cl⁻, Br⁻, I⁻, BF₄⁻, ClO₄⁻, CN⁻, SO₃CF₃⁻, or COOCF₃⁻. The ionic compounds are useful as solvents, and electrolytes for example in electroplating, electrowinning, and electropolishing, and as catalysts.

Claims

1. An ionic compound, having a freezing point of up to 100°

C. formed by the reaction of at least one amine salt of the formula

R¹R²R³R⁴ N⁺X⁻

 

 

(I)

with at least one organic compound (II) which is capable of forming a hydrogen bond with X⁻

,

wherein R¹, R², R³ and R⁴ are each independently;

—

H,

optionally substituted C₁ to C₅ alkyl,

optionally substituted C₆ to C₁₀ cycloalkyl,

optionally substituted C₆ to C₁₂ aryl

optionally substituted C₇ to C₁₂ alkaryl, or wherein

R¹ and R² taken together represent a C₄ to C₁₀ optionally substituted alkylene group, thereby forming with the N atom of formula I a 5 to 11-membered heterocyclic ring, X⁻

is NO₃⁻

, F, Cl⁻

, Br⁻

, I⁻

, BF₄⁻

, ClO₄⁻

, CN⁻

, SO₃CF₃⁻

, or COOCF₃⁻

, and wherein the term “

optionally substituted”

means that the group in question may or may not be substituted with at one or more groups selected from OH, SH, SR⁵, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, CHO, COR⁵ and OR⁵, wherein R⁵ is a C₁ to C₁₀ alkyl or cycloalkyl group,

wherein the molar ratio of I to II is from 1;

1.5 to 1;

2.5.

2. An ionic compound as claimed in claim 1, wherein all of R¹, R², R³ and R⁴ are not identical.

3. An ionic compound as claimed in claim 1 or claim 2, wherein compound II is an organic compound which is solid at 20°

C.

4. An ionic compound as claimed in any one of the preceding claims, wherein compound II is a compound of the formula R⁶COOH, R⁷R⁸NH, R⁹CZNH₂, or R¹⁰OH, wherein:

—

R⁶, R⁷, R⁸, R¹⁰ are each H, a C₁-C₈ alkyl group, an aryl group, or a C₇-C₁₂ alkaryl group optionally substituted with from 0 to 6 groups selected from OH, SR⁵, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, COR⁵ and OR⁵, wherein R⁵ is H, a C₁ to C₁₀ alkyl or cycloalkyl group

R⁹ is a C₁-C₈ alkyl group, C₁-C₁₂ an aryl group, or a C₇-C₁₂ alkaryl group optionally substituted with from 0 to 6 groups selected from OH, SR⁵, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, COR⁵ and OR⁵, wherein R⁵ is H, a C₁ to C₁₀ alkyl or cycloalkyl group, or NHR¹¹, wherein R¹¹ is H or a C₁-C₆ alkyl group, and Z is O or S.

5. An ionic compound as claimed in claim 4, wherein compound II is urea, acetamide, thiourea, glyoxylic acid, malonic acid, oxalic acid dihydrate, trifluoroacetic acid, benzoic acid, benzyl alcohol, phenol p-methyl phenol, o-methyl phenol, m-methyl phenol, p-chloro phenol, D-fructose, or vanillin.

6. An ionic compound as claimed in claim 4, wherein compound II is urea, aniline or a substituted aniline, a C₁-C₆ aliphatic acid, a C₁-C₆ hydroxyaliphatic acid or a dicarboxylic acid of the formula HOOC(CH₂)_nCOOH, wherein n is 0 or 1, acetamide, a phenol or a substituted phenol, an alkylene glycol, or citric acid.

7. An ionic compound as claimed in claim 4, wherein compound II is urea, acetamide, oxalic acid dihydrate, phenol, ethylene glycol, or citric acid.

8. An ionic compound as claimed in claim 1, wherein Compound II has freezing point of less than 160°

C.

9. An ionic compound as claimed in claim 7, wherein Compound II has a freezing point of 20°

C. or less.

10. An ionic compound as claimed in claim 1, wherein Compound II contains only one type of functional group capable of acting as hydrogen bond donor.

11. An ionic compound as claimed in claim 1, wherein the molar ratio of I to II is about 1:

2.

12. An ionic compound as claimed in any one of the preceding claims, wherein R⁴ is a C₁ to C₁₀ alkyl or a cycloalkyl group, substituted with at least one group selected from OH, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, COR⁵, CHO and OR⁵, wherein R⁵ is as defined in claim 1.

13. An ionic compound as claimed in any one of the preceding claims, wherein each of R¹, R², R³, independently is a C₁ to C₅ alkyl or a cycloalkyl group, and R⁴ is hydroxyalkyl.

14. An ionic compound as claimed in claim 9, wherein each of R¹, R², R³, is methyl, and R⁴ is hydroxyethyl.

15. An ionic compound as claimed in any one of the preceding claims, wherein X⁻

is chloride.

16. An ionic compound as claimed in any one of the preceding claims, wherein R¹, R², R³, and R⁴ have the following meaning

17. An ionic compound according to any one of the previous claims in which the amine cation is chiral.

20. The use of an ionic compound according to any of claims 1 to 17 as a solvent, as an electrolyte or as a catalyst.

21. A method of recovering a metal from a metal oxide, which method comprises forming a solution of the metal oxide in an ionic liquid as claimed in any one of claims 1 to 17, and electrolysing the solution to recover the metal.

22. A method as claimed in claim 17, wherein the metal is platinum or palladium.

23. A method of electropolishing a metal article, which method comprises immersing the metal article in an ionic liquid as claimed in any one of claims 1 to 17, and applying a voltage to the article to electropolish the metal.

18. A method of preparing an ionic compound, having a freezing point of up to 100°

C., which method comprises reacting at least one amine salt of the formula

R¹R²R³R⁴N⁺X⁻

 

 

(I)

with at least one organic compound (II) which is capable of forming a hydrogen bond with X⁻

,

wherein R¹, R², R³ and R⁴ are each independently;

—

H,

optionally substituted C₁ to C₅ alkyl,

optionally substituted C₆ to C₁₀ cycloalkyl,

optionally substituted C₆ to C₁₂ aryl

optionally substituted C₇ to C₁₂ alkaryl, or wherein

R¹ and R² taken together represent a C₄ to C₁₀ optionally substituted alkylene group, thereby forming with the N atom of formula I a 5 to 11-membered heterocyclic ring,

X⁻

is NO₃⁻

, F, Cl⁻

, Br⁻

, I⁻

, BF₄⁻

, ClO₄⁻

, CN⁻

, SO₃CF₃⁻

, or COOCF₃⁻

, and wherein the term “

optionally substituted”

means that the group in question may or may not be substituted with at one or more groups selected from OH, SH, SR⁵, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, CHO, COR⁵ and OR⁵, wherein R⁵ is a C₁ to C₁₀ alkyl or cycloalkyl group, wherein the molar ratio of I to II is from 1;

1.5 to 1;

2.5.

19. A method as claimed in claim 18, wherein the reaction is carried out by heating the compound of formula I with the compound of formula II

24. A method of forming a solution of a solute, which method comprises dissolving the solute in an ionic compound, having a freezing point of up to 100°

C. formed by the reaction of at least one amine salt of the formula

R¹R²R³R⁴N⁺X⁻

 

 

(I)

with at least one organic compound (II) which is capable of forming a hydrogen bond with X⁻

,

wherein R¹, R², R³ and R⁴ are each independently;

—

H,

optionally substituted C₁ to C₅ alkyl,

optionally substituted C₆ to C₁₀ cycloalkyl,

optionally substituted C₆ to C₁₂ aryl

optionally substituted C₇ to C₁₂ alkaryl, or wherein

R¹ and R² taken together represent a C₄ to C₁₀ optionally substituted alkylene group, thereby forming with the N atom of formula I a 5 to 11-membered heterocyclic ring, X⁻

is NO₃⁻

, F, Cl⁻

, Br⁻

, I⁻

, BF₄⁻

, ClO₄⁻

, CN⁻

, SO₃CF₃⁻

, or COOCF₃⁻

, and wherein the term “

optionally substituted”

means that the group in question may or may not be substituted with at one or more groups selected from OH, SH, SR⁵, Cl, Br, F, I, NH₂, CN, NO₂, COOR⁵, CHO, COR⁵ and OR⁵, wherein R⁵ is a C₁ to C₁₀ alkyl or cycloalkyl group,

wherein the molar ratio of I to II is from 1;

1.5 to 1;

2.5.