Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
  • A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/04—Pesticides, e.g. insecticides, herbicides, fungicides or nematocides
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/22—Organic substances containing halogen
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/28—Organic substances containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen

Definitions

• the present invention relates to a process for the disposal of chlorinated organic products. More particularly, the present invention relates to a process for the disposal of chlorinated organic products by an oxidation treatment with hydrogen peroxide (H 2 0 2 ), in the presence of Fe(II) ions, optionally associated with other transition metal ions, and of a phase transfer agent.
• H 2 0 2 hydrogen peroxide
• the chlorinated organic products are a class of substances widely used in various technological fields.
• the compounds having alkyl, aromatic, or alkylaromatic structure such as polychlorobiphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), tetrachloroethane, dichlorobenzenes, chlorophenols, hexachlorocyclohexane, or olefinic structure, such as trichloroethylene, are the more common.
• PCBs polychlorobiphenyls
• hydrocarbon mineral oils usually are either dissolved in organic solvents (for example hexachlorobenzene), or impregnated in isolating and/or supporting materials, such as paper, paper-board, wood, etc.
• organic solvents for example hexachlorobenzene
• isolating and/or supporting materials such as paper, paper-board, wood, etc.
• the Applicant has now found a process for the disposal of chlorinated organic products, which comprises oxidating such products with H 2 0 2 in the presence of suitable catalysts and phase transfer agents, with formation of non-toxic substances and possibility of recovering the polluted material, with considerable economical and environmental advantages in comparison with the processes utilized so far.
• an object of the present invention is a process for the disposal of chlorinated organic products, which comprises treating said products with a H 2 0 2 aqueous solution, in the presence of Fe(II) ions, optionally in association with one or more transition metal ions selected from Cu(II), Ti(IV), Mn(II), Co-(II), Ni(II), W(IV) and Mo(IV), and in the presence of a phase transfer agent.
• the reaction involved in the process of the present invention is an oxidation reaction in heterogeneous phase, as the chlorinated organic products are insoluble in the aqueous phase containing the H 2 0 2 /Fe 2+ oxidizing system.
• Necessary is therefore the presence of a phase transfer agent, i.e. of a product which acts as a "bridge" between the molecules of the chlorinated organic product and the oxidizing system.
• a phase transfer agent i.e. of a product which acts as a "bridge" between the molecules of the chlorinated organic product and the oxidizing system.
• phase transfer agents the ones which are advantageously utilizable in the process of the present invention are the ammonium, phosphonium or arsonium salts of general formula: wherein:
• a further class of products utilizable as phase transfer agents in the process of the present invention is the one of ephedrine salts having the formula: wherein:
• phase transfer agents utilizable in the process of the present invention are:
• tetraalkylammonium salts in which the alkyls, like or different from one another, have 1 to 35 carbon atoms, preferably 1 to 12 carbon atoms.
• the chlorinated organic products to be removed are present in amounts ranging from 100 to 5,000 ppm, while the phase transfer agent is utilized in concentrations, referred to the aqueous phase, ranging from 20 to 500 ppm, preferably from 100 to 300 ppm.
• the process of the present invention comprises the use of Fe(II) ions as catalysts, optionally associated with one or more transition metal ions selected, from Cu(II), Ti(IV), Mn(II), Co(II), Ni(II), W(IV) and Mo(IV).
• transition metal ions selected, from Cu(II), Ti(IV), Mn(II), Co(II), Ni(II), W(IV) and Mo(IV).
• Cu(II) ions are preferred.
• Metal ions are added in amounts usually ranging from 50 to 1,000 ppm for the Fe(II) ions and from 0 to 400 ppm for the other transition metal ions indicated above.
• mixtures of Fe(II) ions and Cu(II), Ti(IV), Mn(II), Co-(II), Ni(II), W(IV), or Mo(IV) ions are utilized in equimolar amounts, each of them in concentrations ranging from 50 to 400 ppm, preferably from 150 to 250 ppm.
• the above mentioned metal ions are added in the form of soluble salts.
• Fe(II) ions it is possible to use for instance: ferrous sulphate, ferrous chloride, ferrous nitrate, ammonium ferrous sulphate, etc.
• Heptahydrate ferrous sulphate FeSO 4 ⁇ 7H 2 O is preferred from the operative and economic viewpoint.
• the Cu(II) salts for instance pentahydrate cupric sulphate CUSO 4 ⁇ 5H 2 O can be used.
• hydrogen peroxide it is utilized in the form of an aqueous solution, in such amounts that the molar ratio of added H 2 0 2 to initially present chlorinated product generally ranges from 0.2 to 100, preferably from 0.2 to 30.
• concentration of the hydrogen peroxide aqueous solution is not a discriminating parameter; to simplify the operative modalities, hydrogen peroxide solutions at 30-50% by volume are generally used.
• the hydrogen peroxide solution is preferably added gradually and continuously to the reaction mixture in order to more easily control the reaction conditions, in particular temperature and pH.
• the addition rate usually ranges from 0.2 to 3 ml/min, but it can be varied over a wider range, depending on the specific reaction conditions.
• the reaction temperature can vary over a wide range, generally from 40 ° to 200 ° C, preferably from 70 to 120°C.
• the pH generally ranges from 2 to 7, approximately, preferably from 3 to 4, approximately, and it is maintained in such ranges during the reaction by adding little amounts of a aqueous solution of an acid (for example H 2 SO 4 ) or of a base (for example NaOH).
• the process of the present invention leads to a quantitative conversion of the chlorinated organic product into non-toxic products, accompanied with a good mineralization level of the chlorine atoms, i.e. conversion of the organic chlorine into chlorine ions.
• the reaction mixture is heated to the prefixed reaction temperature and then it is intensely stirred in order to bring the two phases into intimate contact, thereby obtaining a water/oil macroemulsion (the predominant phase being the organic phase).
• reaction trend was followed by withdrawing, after programmed additions of hydrogen peroxide, little amounts of the reaction mixture and by determining the following parameters thereof:
• the resulting mixture was heated in an oil bath to 95 ° C and the pH was adjusted by means of small additions of a 10% NaOH aqueous solution or of a 15% H 2 S0 4 aqueous solutions until a value of about 3.0 was obtained.
• the mixture was intensely stirred in order to form a water-in-oil macroemulsion.
• a H 2 0 2 aqueous solution (45% by volume) was gradually added at a rate of about 0.6 ml/min.
• reaction mixture samples (5 ml each) were drawn for the analysis.
• reaction with 150 ppm of ITBA (Example 1) and the one without ITBA (Example 3) lasted 60 minutes, while the reaction with 300 ppm of ITBA (Example 2) lasted 95 minutes.
• TBAB tetrabutylammonium bromide
• TBAI tetrabutylammonium iodide
• Example 10 From a comparison of the results of Example 10 with the ones obtained in Examples 1, 4 and 7, it is evident that the coupling of the two phase transfer agents of Example 10 permits to best combine a substantially quantitative PCBs oxidation with a good PCBs mineralization degree.
• PCBs-contamined paper 20 g were then introduced into the reactor.
• the PCBs concentration in the paper was equal to 1060 ppm. It was determined on a paper sample (1 g) by means of continuous extraction at room temperature for 14 hours with 20 ml of CH 2 CI 2 ; the PCBs-containing solvent was then analyzed via gas chromatography using methanol as internal standard.
• hexachlorocyclohexane ECE
• ECE hexachlorocyclohexane
• an aqueous solution was added consisting of 100 ml of H 2 0, in which: FeSO 4 ⁇ 7H 2 O and CUSO 4 ⁇ 5H 2 O in such amounts to obtain a concentration equal to 200 ppm for both Fe 2+ and Cu2+ ions; tetrabutylammonium hydroxide (ITBA) in amounts equal to 500 ppm, had been dissolved.
• IBA tetrabutylammonium hydroxide
• the resulting mixture was heated in an oil bath to 95 °C; the pH was adjusted at a value of about 3.4-3.5 by means of small additions of a 15% H 2 S0 4 aqueous solution or of a 10% NaOH aqueous solution.
• the mixture was intensely stirred in order to dissolve all ECE.
• a H 2 0 2 aqueous solution (56% by volume) was gradually added at a rate of about 0.4 ml/min.
• reaction mixture samples (5 ml each) were drawn for analysis.
• H 2 0 2 the added amounts of H 2 0 2 are expressed as number of stoichiometric equivalents; by stoichiometric equivalent is meant the theoretic amount of H 2 O 2 (100%) necessary for the complete oxidation of the organic substances to C0 2 and H 2 0.
• PCF para-chlorophenol
• TCF trichlorophenol
• PECF pentachlorophenol
• an aqueous solution consisting of 250 ml of H 2 0, in which: FeSO 4 ⁇ 7H 2 O and CUSO 4 ⁇ 5H 2 O in such amounts to obtain a concentration equal to 200 ppm for both Fe 2+ and Cu2+ ions; tetrabutylammonium hydroxide (ITBA) in amounts equal to 500 ppm, had been dissolved.
• IBA tetrabutylammonium hydroxide
• the resulting mixture was heated in an oil bath to 95 °C; the pH was adjusted at a value of about 3.0 by means of small additions of a 15% H 2 S0 4 aqueous solution or of a 10% NaOH aqueous solution.
• the mixture was intensely stirred in order to dissolve all PCF, TCF, or PECF.
• a H 2 0 2 aqueous solution (50% by volume) was gradually added at a rate of about 0.2 ml/min.
• reaction mixture samples (5 ml each) were drawn for analysis.

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• Health & Medical Sciences (AREA)
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• Toxicology (AREA)
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• Business, Economics & Management (AREA)
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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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Citations (5)

• 1993
  • 1993-09-13 EP EP93114665A patent/EP0593895B1/fr not_active Expired - Lifetime
  • 1993-09-28 HU HU9302745A patent/HU9302745D0/hu unknown
  • 1993-09-29 JP JP5243211A patent/JPH06198000A/ja active Pending
  • 1993-09-30 CA CA002107455A patent/CA2107455A1/fr not_active Abandoned

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