PROCESS FOR MANUFACTURING AN AQUEOUS HYDROGEN PEROXIDE SOLUTION

Abstract

Process for manufacturing an aqueous hydrogen peroxide solution comprising the following steps: hydrogenating a working solution which comprises an alkylanthraquinone and/or tetrahydroalkylanthraquinone and a mixture of a non-polar organic solvent and a polar organic solvent wherein the concentration of non-polar organic solvent in said mixture is equal to or higher than 30 wt %; oxidizing the hydrogenated working solution to produce hydrogen peroxide; and isolating the hydrogen peroxide, wherein the polar organic solvent is a substituted cyclohexane carbonitrile.

Claims

1-14. (canceled)

15. A process for manufacturing an aqueous hydrogen peroxide solution comprising the following steps: hydrogenating a working solution which comprises an alkylanthraquinone and/or tetrahydroalkylanthraquinone and a mixture of a non-polar organic solvent and a polar organic solvent wherein the concentration of non-polar organic solvent in said mixture is equal to or higher than 30 wt %; oxidizing the hydrogenated working solution to produce hydrogen peroxide; and isolating the hydrogen peroxide, wherein the polar organic solvent is a substituted cyclohexane carbonitrile.

16. The process according to claim 15, wherein the process is a continuous process and wherein the working solution is circulated in a loop through the hydrogenation, oxidation and purification steps.

17. The process according to claim 15, wherein the alkylanthraquinone is chosen from the group consisting of ethylanthraquinones like 2-ethylanthraquinone (EQ), 2-isopropylanthraquinone, 2-sec- and 2-tert-butylanthraquinone (BQ), 1,3-, 2,3-, 1,4- and 2,7-dimethylanthraquinone, amylanthraquinones (AQ) like 2-iso- and 2-tert-amylanthraquinone and mixtures of these quinones.

18. The process according to claim 17, wherein the quinone is EQ, BQ or AQ, preferably EQ.

19. The process according to claim 15, wherein the substituent(s) of the substituted cyclohexane carbonitrile are alkyl group(s), preferably methyl and/or ethyl group(s).

20. The process according to claim 19, wherein the cyclohexane carbonitrile is substituted with at least 2 methyl groups, preferably at least 3 methyl groups and more preferably with at least 4 methyl groups.

21. The process according to claim 15, wherein the substituent group(s) of the cyclohexane carbonitrile is close to the nitrile function, preferably in position 1, 2 and/or 6.

22. The process according to claim 15, wherein the substituted cyclohexane carbonitrile is 3,5-dimethylcyclohexane-1-carbonitrile.

23. The process according to claim 15, wherein the substituted cyclohexane carbonitrile is 2,2,6-trimethyl-cyclohexane-carbonitrile or 1,3,3-trimethyl-cy clohexane-carbonitrile.

24. The process according to claim 15, wherein the substituted cyclohexane carbonitrile is 2,2,6-trimethyl-cyclohexane-carbonitrile which has been synthesized starting from the corresponding acid (2,2,6-trimethyl-cyclohexane-carboxylic acid), which was first transformed in the corresponding carboxylchloride using thionyl chloride, then in the corresponding amide using ammonia and finally, in the corresponding carbonitrile using phosphorus pentoxide.

25. The process according to claim 23, wherein the substituted cyclohexane carbonitrile is 1,3,3-trimethyl-cyclohexane-carbonitrile which has been synthesized by a process comprising the following steps: reacting diethylaluminum cyanide with isophorone; reducing the ketone group with sodium borohydride to give a mixture of diastereomers of 3-cyano-3,5,5-trimethylcyclohexanol; reacting this mixture with methanesulfonyl chloride; eliminating methanesulfonic and leaving a mixture of the cyano-olefins; hydrogenating the resulting olefins over 10% Pd/C in methanol.

26. The process according to claim 15, wherein the substituted cyclohexane carbonitrile has been synthesized in a 2 step reaction comprising first reacting a conjugated diene with a dienophile bearing a nitrile group in order to obtain a substituted cyclohexene carbonitrile and second hydrogenating the double bound of the substituted cyclohexene carbonitrile, wherein at least one of the conjugated diene or the dienophile is substituted preferably by at least one methyl group.

27. The process according to claim 15, wherein there is not more than 80 wt % of non-polar organic solvent in the organic solvents mixture, preferably not more than 60 wt %.

28. The process according to claim 15, wherein the non-polar organic solvent is an aromatic solvent or a mixture of aromatic solvents.

Description

EXAMPLES: SOLUBILITY TESTS OF HYDROGENATED QUINONES IN DIFFERENT SOLVENT MIXTURES

[0047] The determination of the QH solubility was performed on synthetic EQ/ETQ working solutions. These quinones mixed in the tested solvents have been hydrogenated to a fixed level and cooled down successively to 3 different temperatures before the measurement (min. 3 hours to stabilize the system between each measurement). The conditions applied for these tests were:

TABLE-US-00001 EQ concentration 100 g/kg ETQ concentration 140 g/kg Polar solvent variable (*) Level of 10.8Nl H2/kg WS (~116 g of QH/kg of WS hydrogenation or a TL (Test Level) of 16.3 g of H2O2/kg of WS) Temperature of 75 C. hydrogenation Temperatures of 70, 65 and 60 C. precipitation (*) the polar solvents tested were sextate, decanenitrile and TMCH-CN.
They were used in mixture with S-150 in the ratios indicated in FIG. 1 attached, which also shows the results obtained. In this FIGURE, Kb stands for the weight partition coefficient of hydrogen peroxide between the water and the working solution (mixture of quinones and organic solvents). It is calculated using the following formula:

Kb=(g H2O2/kg aqueous phase)/(g H2O2/kg organic phase)

[0048] FIG. 1 demonstrates the very high potential of cyclohexanecarbonitrile structures versus linear nitriles like decanenitrile.

[0049] The complete data are available in Table 1 attached.

[0050] The maximum solubility of a hydrogenated quinone (QH) in a solvent mixture is directly correlated with the productivity of the working solution. The higher is the QH solubility, the higher will be the theoretical quantity of hydrogen peroxide achievable per kg of WS (Productivity). These theoretical values, designated by the terms Productivity (gH2O2/kg of WS) measured in Table 1, were calculated as follows:

[0051] 1 mole (240 g) ETQH (which actually is the QH in our Examples) per kg of WS will produce 1 mole (34 g) of H2O2 per kg of WS. Hence, the test level in our Examples equals: 34*QH/240.

[0052] Again, the values obtained with TMCH-CN are much higher (almost the double in fact) than with sextate or a linear nitrile like decanenitrile.

[0053] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

TABLE-US-00002 TABLE 1 Trials with synthetic quinones (EQ + ETQ) Methylcyclo- 2,2,6-trimethylcyclo hexylacetate Decanenitrile hexanecarbonitrile Polar Solvent used Sextate Decanenitrile TMCH-CN TMCH-CN (40%) (65%) (60%) (50%) Composition EQ g/kg 100 of working ETQ g/kg 140 solution CUR dry residue g/kg 0 Solvent mix g/kg 760 Mass ratio of polar solvent in solvent % 40 35 60 50 Mass ratio of S150 in solvent % 60 65 40 50 Kb of the solvents mix 176 171 171 247 Density of polar solvents at amb T Kg/l 0.94 0.83 0.89 0.89 QH (g/kg) measured at . . . 60 C. 52 62.2 110 73.9 65 C. 60.8 71.5 full 80.3 soluble 70 C. 68 78.6 full full soluble soluble Productivity (gH2O2/kg) 60 C. 7.4 8.8 15.6 10.5 measured at . . . 65 C. 8.6 10.1 full 11.4 soluble (>17) 70 C. 9.6 11.1 full full soluble (>17) soluble (>17)

TABLE-US-00003 TABLE 2 Dienophiles Conjugated dienes [00001] [00002] [00003] [00004] [00005] [00006] [00007] [00008] [00009] [00010] [00011] [00012] [00013] [00014] [00015] [00016] [00017] [00018] [00019] [00020] [00021] [00022]