Method for the preparation of reactive hydrogen peroxide in deep eutectic solvents
The subject invention provides a potentially economically viable method for the preparation of hydrogen peroxide (H 2 O 2 ) in deep eutectic solvents (DES). H 2 O 2 is then used for the destruction of small to large quantities of sulfur and nitrogen mustards and lewisite, their homologous/analogues, and similar chemical warfare agents at ambient conditions in DES without producing any toxic by-products. Furthermore, H 2 O 2 has been used for the destruction of small to large quantities of halogenated hydrocarbons, their homologous/analogues, and similar hazardous chemicals at ambient conditions. H 2 O 2 can be formed by either the electrochemical reduction of oxygen in DES in the presence of water or by dissolving Group 1 (alkali metals) or Group 2 (alkaline earth metals) superoxides, e.g. potassium superoxide, in DES in the presence of water, with/without chemicals used for the enhancement of the solubility of the metal superoxide in the DES, e.g. crown ethers.
1. A method for the preparation of reactive hydrogen peroxide ion in deep utectic solvents by the electrochemical reduction of oxygen in the deep eutectic solvent or mixture of deep eutectic solvents; in the presence of small quantity of water (less than 10 wt %), wherein the deep eutectic solvent (DES) is a compound, having a freezing point of up to 100° C. formed by the reaction of at least one amine salt of the formula
R 1 R 2 R 3 R 4 N + X − (I)
with at least one organic compound (II) which is capable of forming a hydrogen bond with X − ,
wherein R 1 , R 2 , R 3 and R 4 are each independently:—
H,
optionally substituted C 1 to C 5 alkyl,
optionally C 6 to C 10 cycloalkyl,
optionally substituted C 6 to C 12 aryl
optionally substituted C 7 to C 12 alkaryl, or wherein
R 1 and R 2 taken together represent a C 4 to C 10 optionally substituted alkylene group, 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, SR 5 , Cl, Br, F, I, NH 2 , CN, NO 2 , COOR S , CHO, COR 5 and OR 5 , wherein R 5 is a C 1 to C 10 alkyl or cycloalkyl group,
wherein the organic compound II is
i) 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;
ii) aniline or a substituted aniline a C 1 -C 6 aliphatic acid, a C 1 -C 6 hydroxyaliphatic acid, or a dicarboxylic acid of the formula HOOC(CH 2 ) n COOH, wherein n is 0 or 1, acetamide, a phenol or a substituted phenol, an alkylene glycol, citric acid, ethylene glycol,
wherein the molar ratio of I to II is from 1:1.5 to 1:2.5;
b) maintaining the mixture of step a) at a temperature from 10° to 100° C.; and
c) the electrochemical generation of the superoxide ion in the mixture by the reduction of oxygen in the mixture wherein the suoeroxide ion generated in situe will destroy the halogenated hydrocarbons.
2. A method as recited in claim 1 , where the superoxide ion is generated by dissolving Group 1 (alkali metals) or Group 2 (alkaline earth metals) superoxides, e.g. potassium superoxide, in deep eutectic solvents in the presence of water of less than 10 wt %.
3. A method as recited in claim 2 , where an additional compound, e.g. crown ether, is added to enhance the solubility of metal superoxide in deep eutectic solvents.
4. The method of claim 1 , where the mixture is at a pressure of not more than about 1 to 3 atmospheres.
5. The method of claim 1 , where the mixture is at a temperature between 10° C. and 100° C.
6. A method as in claim 1 , wherein compound II has freezing point of less than 160° C.
7. A method as in claim 1 , wherein compound II has a freezing point of 20° C. or less.
8. A method as in claim 1 , wherein compound II contains only one type of functional group capable of acting as hydrogen bond donor.
9. A method as in claim 1 , wherein the molar ratio of I to II is about 1:2.
10. A method as in claim 1 , wherein R 4 is a C 1 to C 10 alkyl or a cycloalkyl group, substituted with at least one group selected from OH, Cl, Br, F, I, NH 2 , CN, NO 2 , COOR 5 , COR 5 , CHO and OR 5 .
11. A method as claimed in claim 1 , wherein X − is chloride.
12. A method as claimed in claim 1 , wherein R 1 , R 2 , R 3 , and R 4 are as shown in the following table
R 1
R 2
R 3
R 4
Me
Me
Me
C 2 H 4 OH
Me
Me
Benz
C 2 H 4 OH
Me
Me
Et
C 2 H 4 OH
Me
Me
Me
Benz
Me
Me
Me
C 2 H 4 OCOMe
Me
Me
Me
C 2 H 4 Cl
Me
Me
Me
ClCH 2 CHOHCH 2 (R)
Me
Me
Me
ClCH 2 CHOHCH 2 (S)
Me
H
H
H
Me
Me
H
H
Et
Et
Et
H
Et
Et
Et
Benz
Me
Benz
C 2 H 4 OH
C 2 H 4 OH
Me
H
H
CH 2 COOH
Me
Me
Me
Et
Me
Me
Me
C 2 H 4 F
Me
Me
Me
Me(CH 2 ) 11 M
Et
Et
Et
Me
Et
Et
Et
Benz
Me
Me
C 2 H 4 OH
C 2 H 4 OH
wherein Me is methyl, Et is ethyl, and Benz is benzyl.
13. A method according to claim 1 , in which the amine cation is chiral.
14. A method for the destruction of halogenated hydrocarbons using H 2 O 2 produced in claim 1 .
15. A method for the destruction of sulfur and nitrogen mustards and lewisite, their homologous/analogues, and similar chemical warfare agents using H 2 O 2 produced in claim 1 .