Preparation of an aqueous reagent for the absorption or destruction of pollutants

Abstract

Process for treating a medium by the removal or destruction of one or more undesired substances present in said medium, comprising combining hydrogen peroxide and alkali hydroxide in an aqueous solution to form superoxide, and bringing the resultant superoxide-containing solution into contact with said medium. The process is useful for the destruction of halogenated organic pollutants and also for carbon dioxide removal from flue gases. The process can also be applied for soil remediation.

Claims

1. A process for treating a medium by the removal or destruction of one or more undesired substances present in said medium, comprising combining hydrogen peroxide and alkali hydroxide in an aqueous solution in a molar ratio from 1.2:1 to 2:1 (H.sub.2O.sub.2:OH.sup.−) to form superoxide, wherein the hydroxide is added to the aqueous solution at a concentration of not less than 1.5 M, and bringing the resultant superoxide-containing solution into contact with said medium.

2. A process according to claim 1, wherein the medium to be treated is halogenated organic pollutant-contaminated soil.

3. A process according to claim 2, wherein the halogenated pollutant contaminating the soil is chlorinated methane.

4. A process according to claim 3, which is a site remediation process, comprising injecting into halogenated organic pollutant-contaminated soil a first stream of hydrogen peroxide solution and a second stream of aqueous alkali hydroxide, or a combined stream of both, such that the molar ratio between the hydrogen peroxide and the hydroxide ion is in the range of 1.2:1 to 2:1.

5. A process according to claim 4, wherein the ratio between the hydrogen peroxide and hydroxide is from 1.4:1 to 1.6:1 (H.sub.2O.sub.2:OH.sup.−).

6. A process according to claim 1, wherein the hydrogen peroxide and the hydroxide source are combined at a molar ratio of from 1.2:1 to 1.6:1 (H.sub.2O.sub.2:OH.sup.−).

7. A process according to claim 6, wherein the hydrogen peroxide and the hydroxide source are combined at a molar ratio from 1.4:1 to 1.6:1(H.sub.2O.sub.2:OH.sup.−).

8. A process according to claim 6, wherein the hydroxide is added to the aqueous solution at a concentration in the range of 2.25 to 20 M.

9. A process according to claim 8, wherein the hydroxide is added to the aqueous solution at a concentration in the range of 3.0 to 9.0 M.

10. A process according to claim 1, wherein the medium to be treated is a gaseous mixture from which carbon dioxide is removed.

11. A process according to claim 10, wherein the carbon dioxide is absorbed by the superoxide-containing aqueous solution in a gas-liquid contactor, whereby said carbon dioxide is converted into an alkali carbonate salt, which is subsequently treated with calcium hydroxide to regenerate the corresponding alkali hydroxide and concurrently form calcium carbonate.

12. The process of claim 11, wherein the calcium carbonate is treated to form calcium hydroxide, which is recycled for regenerating the alkali hydroxide.

13. A process according to claim 1, wherein the medium to be treated consists solely of one or more halogenated organic pollutant(s) to be destroyed, wherein said medium is brought into contact with the superoxide-containing solution in the presence of a phase transfer catalyst.

14. A process according to claim 13, wherein the halogenated organic pollutant is halogenated aliphatic hydrocarbon.

15. A process according to claim 14, wherein the pollutant is selected from the group consisting of halogenated methane, halogenated ethane and halogenated ethylene compounds.

16. A process according to claim 13, wherein the phase transfer catalyst is composed of a nitrogen-containing cation and an anion which is displaceable by a superoxide anion.

17. A process according to claim 16, wherein the phase transfer catalyst is quaternary ammonium salt of the formula N.sup.+R.sub.1R.sub.2R.sub.3R.sub.4Hal.sup.−, wherein each of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is independently C.sub.1-C.sub.18 alkyl group and Hal.sup.− indicates halide anion.

18. A process according to claim 17, wherein the quaternary ammonium salt is selected from the group consisting of:
N.sup.+CH.sub.3[(CH.sub.2).sub.kCH.sub.3].sub.3Hal.sup.−,
N.sup.+(CH.sub.3).sub.2[(CH.sub.2).sub.kCH.sub.3].sub.2Hal.sup.−, or
N.sup.+[(CH.sub.2).sub.kCH.sub.3].sub.4Hal.sup.−, wherein k is at least 5.

19. A process according to claim 18, wherein the quaternary ammonium salt has the formula N.sup.+CH.sub.3[(CH.sub.2).sub.kCH.sub.3].sub.3Hal.sup.−, in which k is between 5 and 9.

20. A process according to claim 1, wherein the medium to be treated is halogenated organic pollutant-contaminated liquid, which is brought into contact with the superoxide-containing solution in the presence of a phase transfer catalyst.

Description

(1) In the Figures:

(2) FIG. 1 illustrates a scrubbing apparatus suitable for carrying out the absorption of CO.sub.2 from a gaseous mixture.

(3) FIG. 2 illustrates the experimental set-up employed in the experimental work regarding CO.sub.2 absorption.

(4) FIG. 3 is a schematic illustration of CO.sub.2 absorption process, including the regeneration of sodium hydroxide.

(5) FIG. 4 shows the IR spectra of an aqueous absorption solution comprising sodium hydroxide and hydrogen peroxide.

(6) FIG. 5 is a graph showing the absorption of CO.sub.2 by an aqueous hydroxide solution in the presence and absence of H.sub.2O.sub.2, plotted versus time.

(7) FIG. 6 is a graph depicting the efficiency of CO.sub.2 absorption by NaO.sub.2 in comparison to NaOH and MEA.

(8) FIG. 7 is a graph illustrating the temperature dependence of CO.sub.2 absorption by the superoxide anion.

(9) FIG. 8 is a graph illustrating CO.sub.2 absorption by an aqueous solution of hydrogen peroxide and different hydroxide salts.

(10) FIG. 9 is a graph depicting CO.sub.2 absorption at different hydroxide concentrations.

(11) FIG. 10 is a graph showing the absorption of CO.sub.2 at various peroxide:hydroxide molar ratios.

(12) FIG. 11 illustrates a method for recycling the hydroxide used in the process of CO.sub.2 absorption.

(13) FIG. 12 illustrates an apparatus for carrying out the destruction of CCl.sub.4 by the process of the invention.

(14) FIG. 13 shows the degree of CCl.sub.4 destruction as function of mineralization agent.

(15) FIG. 14 shows the degree of CH.sub.3I destruction as function of mineralization agent.

(16) FIG. 15 is a bar diagram illustrating the effect of the presence of a phase transfer catalyst in the destruction of halogenated pollutant.

(17) FIG. 16 demonstrates the destruction of chlorobenzene.

EXAMPLES

Materials

(18) Carbon dioxide gas cylinders 30% (w/w) in nitrogen was purchased from Maxima gas supplier, Israel.

(19) Carbon dioxide gas cylinders 100% was purchased from Mushilion gas supplier, Israel.

(20) 30% aqueous hydrogen peroxide solution was purchased from Bio Lab ltd, Israel.

(21) Sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, monoethanolamine (MEA), halogenated alkanes and alkenes (e.g., methyl iodide, carbon tetrachloride, bromotrichloro methane), Aliquat 336, CTAB, DDAB, and TOAB were purchased from Sigma Aldrich ltd, Israel.

(22) Measurements

(23) Gas chromatography (GC) studies were conducted using GC with FID detector Framewax™ 30 m, 0.32 mm ID, 0.25 μm, manufactured by Resteck ltd, U.S.

(24) FTIR studies were conducted using Peact IR 4000, manufactured by Metier.

(25) XRD studies were conducted using X-ray diffractometer, Range: 110°<2θ>168°, D8 advance by Bruker AXS.

(26) CO.sub.2 concentration was determined using a gas analyzer manufacture by Emproco ltd Israel.

(27) CO.sub.2 Absorption Measurement Set-Up

(28) The experimental set-up used in the following examples is shown schematically in FIG. 2. CO.sub.2 was made to flow through a flow meter (22) at a flow rate of 1 L/minute into a gas trap (24) loaded with the aqueous absorbing solution, which was continuously stirred by a magnetic stirrer (23). The CO.sub.2 source was a commercial 100% CO.sub.2 or commercial 30% (w/w) CO.sub.2 in nitrogen gas cylinder (21). The contact time between the CO.sub.2 and the absorbing solution in the gas trap was approximately 0.01 seconds. Gases exiting the gas trap were directed through an O.sub.2/CO.sub.2 analyzer (25) connected to a computer (26).

(29) The initial CO.sub.2 concentration was measured by using a bypass (27), through which the CO.sub.2 flows directly into the analyzer, thus determining the CO.sub.2 concentration at time zero. Subsequently the absorber trap was connected, and the CO.sub.2 gas concentration in the outlet of the trap was measured. The absorption yield was calculated by the following formula:
% absorption=[CO.sub.2TimeZero—CO.sub.2Measured]/CO.sub.2TimeZero.

Example 1

CO2 Absorption by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide

(30) An aqueous absorption solution comprising water (30 mL), sodium hydroxide (10 grams; 0.25 mol) and 0.375 mol hydrogen peroxide (11.3 mL of 30% H.sub.2O.sub.2 aqueous solution) was prepared. The formation of superoxide in the solution was confirmed by Fourier transform infrared spectroscopy (FTIR). The spectrum of the absorption medium, depicted in FIG. 4, includes a peak at 1108 cm.sup.−1 attributed to the O.sub.2.sup.− molecule.

(31) The absorption of CO.sub.2 by the absorption solution was measured using the experimental set-up described above. The gas trap was loaded with the absorption solution. The experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(32) For the purpose of comparison, CO.sub.2 absorption was measured under the same conditions in the absence of hydrogen peroxide, using an alkaline solution consisting of 0.25 mol (10 grams) sodium hydroxide dissolved in 30 ml of water as the absorption solution. The absorption of CO.sub.2 by monoethanolamine (abbreviated MEA) was also tested under the same conditions using 30 mL water and 0.25 mol (15.27 grams) MEA as the absorption solution.

(33) The results are presented graphically in FIG. 5 which shows the CO.sub.2 absorption (as percent relative to the initial CO.sub.2 concentration) against time (in seconds) in the presence and absence of hydrogen peroxide. As shown, the absorption of CO.sub.2 by an aqueous solution of sodium hydroxide and hydrogen peroxide reached approximately 100% for a duration of about 130 seconds. CO.sub.2 absorption in the absence of hydrogen peroxide, in contrast, reached a maximum value of merely 20%.

(34) FIG. 6 depicts the conversion of CO.sub.2 by the aqueous solution of sodium hydroxide and hydrogen peroxide as the absorption solution, in comparison to sodium hydroxide and MEA. It may be appreciated that the total CO.sub.2 conversion by the absorption medium of the invention reached over 90%, in comparison to about 20% by each of the NaOH and MEA solutions.

Example 2

CO2 Absorption by an Aqueous Solution of Sodium Hydroxide and Hydrogen Peroxide at Different Temperatures

(35) The absorption of CO.sub.2 by an aqueous solution of sodium hydroxide and hydrogen peroxide was measured using the experimental set-up described above. The gas trap was loaded with an aqueous solution consisting of water (30 mL), sodium hydroxide (10 grams; 0.25 mol) and 0.375 mol hydrogen peroxide (11.3 mL 30% H.sub.2O.sub.2 aqueous solution). The experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(36) The above experiment was carried out under the same conditions at four different temperatures (298 K, 313 K, 323 K and 353 K).

(37) FIG. 7 depicts the absorption of CO.sub.2 over time for each of the four temperatures. As shown, the CO.sub.2 absorption value reaches 100% throughout the entire tested temperature range.

Example 3

CO2 Absorption by an Aqueous Solution of Hydrogen Peroxide and Sodium or Potassium Hydroxide

(38) The absorption of CO.sub.2 by an aqueous solution of hydrogen peroxide and a hydroxide salt was measured using the experimental set-up described above. The experiment was carried out at room temperature (298 K). The gas trap was loaded with water (30 mL), 0.375 mol hydrogen peroxide (11.3 mL 30% H.sub.2O.sub.2 aqueous solution) and 0.25 mol of the tested hydroxide salt. The experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(39) The results are graphically presented in FIG. 8, where the abscissa indicates the time (seconds) and the ordinate indicates the CO.sub.2 absorption. It may be appreciated that the two bases tested, sodium hydroxide and potassium hydroxide, are both highly effective with the former being slightly better.

Example 4

The Effect of Hydroxide Concentration on CO2 Absorption

(40) The absorption of CO.sub.2 by an aqueous solution of hydrogen peroxide and sodium hydroxide was measured using the experimental set-up described above. A set of experiments was carried out using as absorption medium consisting of water (30 mL), 0.375 mol hydrogen peroxide (11.3 mL 30% H.sub.2O.sub.2 aqueous solution) and various quantities of sodium hydroxide. The tested sodium hydroxide concentrations were 0.625 M, 1.25 M, 1.88M, 2.5 M, 5.0 M and 6.25 M. Each experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(41) FIG. 9 illustrates the absorption of CO.sub.2 over time for each of the six sodium hydroxide concentrations.

(42) The absorption of CO.sub.2 at a sodium hydroxide concentration of 0.625 M and 1.25 M is unsatisfactory. A sharp increase of the absorption of CO.sub.2 is observed upon increasing the concentration of the hydroxide. The CO.sub.2 absorption at a sodium hydroxide concentration of 6.25 M (corresponding to a H.sub.2O.sub.2:OH molar ratio of 1.5:1) reaches 100%.

Example 5

The Effect of Hydrogen Peroxide Concentration on CO2 Absorption

(43) The absorption of CO.sub.2 by an aqueous solution of sodium hydroxide and hydrogen peroxide was measured using the experimental set-up described above. A set of experiments was carried out using as absorption medium consisting of water (30 mL), sodium hydroxide (10 grams; 0.25 mol) and various quantities of hydrogen peroxide. The tested hydrogen peroxide concentrations were 9.25 M, 6.25 M and 5 M. Each experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(44) The results are depicted in FIG. 10. The CO.sub.2 absorption value at a hydrogen peroxide concentration of 9.25 M, corresponding to a H.sub.2O.sub.2:OH molar ratio of 1.5:1, reaches 100%. A lower hydrogen peroxide concentration results in reduced CO.sub.2 absorbing capacity.

Example 6

Regeneration of Sodium Hydroxide

(45) The absorption of CO.sub.2 by an aqueous solution of sodium hydroxide and hydrogen peroxide was measured using the experimental set-up described above. The gas trap was loaded with 1.6 mol water (30 mL), 0.25 mol sodium hydroxide (10 grams) and 0.37 mol hydrogen peroxide (11.3 mL 30% H.sub.2O.sub.2 aqueous solution). The experiment was allowed to continue for five minutes, during which the CO.sub.2 absorption was measured periodically.

(46) Four consecutive cycles of CO.sub.2 absorption were carried out, wherein following each cycle, calcium hydroxide (0.25 mol, 10 grams) was added to the gas trap and the reaction mixture was stirred for 3 minutes in order to regenerate sodium hydroxide, following which an additional 0.37 mol of hydrogen peroxide (11.3 mL 30% H.sub.2O.sub.2 aqueous solution) was added to the gas trap.

(47) FIG. 11 depicts the absorption of CO.sub.2 (percent relative to the initial CO.sub.2 concentration) as a function of time (seconds) for each of the four absorption cycles, demonstrating that the sodium hydroxide regeneration is fairly effective.

Example 7

Carbon Tetrachloride Mineralization by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide in the Presence of Phase Transfer Catalyst

(48) The experiments described below were conducted in an adiabatic glass reactor (100 ml) equipped with a reflux condenser and magnetic stirrer at ambient conditions.

(49) A mixture of 4 ml CCl.sub.4 (50 mmol), 8 gr sodium hydroxide (200 mmol), 1.1 gr Aliquat 336 (2.5 mmmol), 9.3 ml 30% hydrogen peroxide (300 mmol) and 30 ml distilled water were fed into the reactor in one batch. Stirring was continued for 10 minutes at room temperature. The progress of the reaction was monitored by volumetric analysis of the released carbon dioxide, and measuring the reaction temperature. The released carbon dioxide was captured in an aqueous barium hydroxide scrubber, in order to allow the precipitation of barium carbonate. The precipitated barium carbonate was filtered, dried and weighed to confirm the overall mass balance. After the reaction was completed, the aqueous and organic phases were separated and washed by 10 ml of dichloromethane. The organic phases were combined. The organic solution was tested for the presence of CCl.sub.4 by means of GC with FID detector; no traces of CCl.sub.4 were detected. The aqueous phase was dried at evaporator and the final reaction solid products were determined by means of X-ray diffraction (XRD) analysis, which indicated that the reaction products of CCl.sub.4 mineralization consist of sodium chloride and sodium carbonate.

(50) For the purpose of comparison, CCl.sub.4 mineralization was investigated using three comparative reagents:

(51) (i) sodium hydroxide alone [an alkaline solution consisting of 0.25 mol (10 grams) sodium hydroxide dissolved in 30 ml of water]; the conditions of the experiment were as set out above.

(52) (ii) hydrogen peroxide alone [9.3 ml of 30% hydrogen peroxide (300 mmol) in 30 ml distilled water]; the conditions of the experiment were as set out above.

(53) (iii) solid potassium superoxide (KO.sub.2). The experiment was conducted in an adiabatic glass reactor (100 ml) equipped with a reflux condenser and a magnetic stirrer at ambient conditions. A mixture of 4 ml CCl.sub.4 (50 mmol) and 10 gr potassium superoxide (150 mmol) was fed into the reactor in one batch. Stirring was continued for 1 hour. The liquid and organic phases were then separated and washed by 10 ml of dichloromethane. The organic solution was tested for the presence of CCl.sub.4 by means of GC with FID detector.

(54) The results of the experiment according to the invention and the three comparative experiments are presented graphically in FIG. 13 which shows the CCl.sub.4 destruction as function of the mineralization agent. As shown, the mineralization of CCl.sub.4 by means of an aqueous solution of sodium hydroxide and hydrogen peroxide (“The Reagent”) reached approximately 100% following a reaction which lasted only ten minutes, in comparison to only negligible efficacy demonstrated by the NaOH, H.sub.2O.sub.2 and KO.sub.2 reagents.

Example 8

Methyl Iodide Mineralization by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide in the Presence of Phase Transfer Catalyst

(55) The experiments were conducted in an adiabatic glass reactor (100 ml) equipped with a reflux condenser and magnetic stirrer at ambient conditions.

(56) A mixture of methyl iodide (4 ml, 50 mmol), sodium hydroxide (8 gr, 200 mmol), Aliquat 336 (1.1 gr, 2.5 mmol), 30% hydrogen peroxide (9.3 ml, 300 mmol) and 30 ml distilled water were fed into reactor in one batch. Stirring was continued for 10 minutes at room temperature. The progress of the reaction was monitored by volumetric analysis of the released carbon dioxide, and measuring the reaction temperature. The released carbon dioxide was captured in an aqueous barium hydroxide scrubber, in order to allow the precipitation of barium carbonate. The precipitated barium carbonate was filtered, dried and weighed to confirm the overall mass balance. After the reaction was completed the aqueous and organic phases were separated and washed by 10 ml of dichloromethane. The organic phases were combined. The organic solution was tested for the presence of CH.sub.3I by means of GC with FID detector; no traces of CH.sub.3I were detected. The aqueous phase was dried at evaporator and the final reaction solid products were determined by means of X-ray diffraction (XRD) analysis, which indicated that the reaction products of CH.sub.3I mineralization consist of sodium iodide and sodium carbonate.

(57) For the purpose of comparison, CH.sub.3I mineralization was investigated using two comparative reagents:

(58) (i) sodium hydroxide alone [an alkaline solution consisting of 0.25 mol (10 grams) sodium hydroxide dissolved in 30 ml of water]; the conditions of the experiment were as set out above.

(59) (ii) hydrogen peroxide alone [9.3 ml of 30% hydrogen peroxide (300 mmol) in 30 ml distilled water]; the conditions of the experiment were as set out above.

(60) The results of the experiment according to the invention and the two comparative experiments are presented graphically in FIG. 14 which shows the CH.sub.3I destruction as function of the mineralization agent. As shown, the mineralization of methyl iodide by means of an aqueous solution of sodium hydroxide and hydrogen peroxide (“Our Reagent”) reached approximately 100% following a reaction which lasted ten minutes, in comparison to only negligible efficacy demonstrated by the NaOH and H.sub.2O.sub.2 reagents.

Example 9

Carbon Tetrachloride Mineralization by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide in the Presence of Various Phase Transfer Catalysts

(61) In the following set of experiment, the effect of the phase transfer catalyst was investigated. The phase transfer catalysts tested were Aliquat 336, CTAB, DDAB, and TOAB. The experiments were conducted in an adiabatic glass reactor (100 ml) equipped with a reflux condenser and magnetic stirrer at ambient conditions.

(62) A mixture of CCl.sub.4 (4 ml, 50 mmol), sodium hydroxide (8 gr, 200 mmol), PTC (1.1 gr, 2.5 mmol), 30% hydrogen peroxide (9.3 ml, 300 mmol) and 30 ml distilled water were fed into reactor in one batch. Stirring was continued for 10 minutes at room temperature. The reaction mixture was treated as set out in previous examples.

(63) For the purpose of comparison, CCl.sub.4 mineralization was measured under the same conditions but without any PTC. The results are graphically depicted in FIG. 15. As shown, the mineralization of CCl.sub.4 can be accomplished to a satisfactory extent in the presence of different types of PTC's, with Aliqout 336 demonstrating the best activity.

Example 10-14

Mineralization of Halogenated Compounds by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide

(64) In the following set of experiments, various halogenated pollutants were treated by means of the method of the invention according to the procedure described in Example 8. The details of the experiments and the results are tabulated in Table 1.

(65) TABLE-US-00001 TABLE 1 Reaction Reaction Reaction conditions: Halogenated Reaction Conversion Time ratio of Ex. compounds Products (%) (min) NaOH:H.sub.2O.sub.2 10 CCl.sub.3Br Na.sub.2CO.sub.3, 100 5 1:1.5 NaCl, NaBr, O.sub.2 11 CHCl.sub.2Br Na.sub.2CO.sub.3, 100 5 1:1.5 NaCl, HBr, O.sub.2 12 CHI.sub.3 Na.sub.2CO.sub.3, NaI, 100 5 1:1.5 HI, O.sub.2 13 CHBr.sub.3 Na.sub.2CO.sub.3, NaBr, 100 5 1:1.5 HBr, O.sub.2 14 CH.sub.3Cl Na.sub.2CO.sub.3, NaCl, 100 5 1:1.5 O.sub.2

Example 15-23

Mineralization of Halogenated Organic Compounds in Soil by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide

(66) The experiments described below were conducted in an adiabatic glass reactor (500 ml) which contained 60 gr of soil. The tested halogenated organic compound (0.05-0.3 mol) was sponged in the soil. Two different syringes (50 ml) were prepared, one containing 16.6M sodium hydroxide solution and the other 22 ml of 30% hydrogen peroxide solution (710 mmol H.sub.2O.sub.2). The solutions were injected simultaneously into the soil and the treatment was allowed to continue over a period of tem minutes. After the reaction was completed, the treated soil was washed with 100 ml of dichloromethane on a Buchner funnel. The solid and liquid fractions were separated. The liquid (aqueous and organic) phases were separated in a separation funnel and the organic phases were combined. The organic solution was tested for the presence halogenated organic compounds by means of GC with FID detector. The conditions of the experiments and the results are tabulated in Table 2.

(67) TABLE-US-00002 TABLE 2 Reaction Reaction Reaction conditions: Halogenated Reaction Conversion Time ratio of Ex. compounds Products (%) (min) NaOH:H.sub.2O.sub.2 15 CCl.sub.4 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 Cl.sub.2, O.sub.2 16 CCl.sub.3Br Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 NaBr, O.sub.2 17 CHCl.sub.2Br Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 NaBr, O.sub.2 18 C.sub.2H.sub.3Cl.sub.3 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 O.sub.2 19 C.sub.2H.sub.3Cl.sub.2Br Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 NaBr, O.sub.2 20 C.sub.2H.sub.3ClBr.sub.2 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 NaBr, O.sub.2 21 C.sub.2H.sub.2Cl.sub.2 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 O.sub.2 22 C.sub.2HCl.sub.3 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 O.sub.2 23 C.sub.2Cl.sub.4 Na.sub.2CO.sub.3, NaCl, 100 10 1:1.5 O.sub.2

Example 24

Chlorobenzene Destruction by an Aqueous Solution of Hydrogen Peroxide and Sodium Hydroxide in the Presence of Phase Transfer Catalyst

(68) Into a glass vessel (50 ml) equipped with a reflux condenser and magnetic stirrer were added chlorobenzene (7.35 g ml, 50 mmol), Aliquat 336 (0.4 gr, 1 mmol), 30% hydrogen peroxide (6.9 ml, 225 mmol), sodium hydroxide (6 gr, 150 mmol) and 34 ml distilled water. Stirring was continued for 10 minutes at room temperature.

(69) The graph shown in FIG. 16 demonstrates the progress of the reaction, where the abscissa indicates the time of the reaction and the ordinate the degree of chlorobenzene conversion. The Conversion is given by (1-C.sub.A/C.sub.A0), in which C.sub.A is the reactant (chlorobenzene) concentration and C.sub.A0: initial reactant (chlorobenzene) concentration. As shown by the graph, following ten minutes reaction at ambient conditions, chlorobenzene was converted completely (apparently into a more oxidized state).