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
  • A62D3/36—Detoxification by using acid or alkaline reagents
• • 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

Definitions

• the present invention relates to a safe method for decomposing halogenated aromatic compounds such as polychlorinated biphenyl (hereinafter "PCB") using alkalis in a polar solvent.
• PCB polychlorinated biphenyl
• U.S. Patent No. 4,532,028 discloses a method of reacting alkali and a PCB content of up to 50,000 ppm at a temperature of 200° C or below in a mixture of alkyl or alkylene sulfoxide and polyole, thereby reducing the content to several ppm.
• Other examples include Canadian Patent No. 1,181,771 which discloses a method employing melted sodium, and Italian Patent No. 1,206,508 which disclose a method using alkaline earth metal on which polyethylene glycol is adsorbed.
• halogenated aromatic compounds are contacted at a high temperature with such an amount of alkalis that cannot be dissolved into the non-proton solvent.
• the contact is carried out at a temperature ranging from about 150° C to about 300° C, for 1 to 10 hours, and the blending ratio of alkalis to the whole reaction system when the reaction starts is 5,000 mg/kg or more.
• the blending ratio of alkalis to the whole reaction system when the reaction starts be 7,000 mg/kg or more.
• the halogenated aromatic compounds to be decomposed include one halogenated aromatic compound selected from a group consisting of polychlorinated biphenyl, polychlorinated terphenyl, polybrominated biphenyl, and analogous compounds thereof, or a mixture of two or more halogenated aromatic compounds selected from this group.
• the action of the non-proton polar solvent is promoted by making the amount of the alkalis larger than that of the non-proton polar solvent rather than by making the amount of the alkalis larger than that of the halogenated aromatic compounds.
• the starting material is 100 % halogenated aromatic compounds or halogenated aromatic compounds diluted to several ppm, it was confirmed that the halogenated aromatic compounds are decomposed to such an extent that the halogenated aromatic compounds are substantially undetectable. Therefore, according to the present invention, it is possible to treat not only 100 % halogenated aromatic compounds but also halogenated aromatic compounds diluted to the concentration ranging from 2 ppm to 80 % by hydrocarbon oil, for example, the principal component of which is non-aromatic hydrocarbon.
• alkalis one alkali selected from a group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2) and magnesium hydroxide (Mg(OH)2), or a mixture of two or more alkalis selected from this group can be used.
• Calcium hydroxide (Ca(OH)2) and others may be added to the reaction system in the form of the alkalis being oxides such as calcium oxide (CaO).
• these non-proton polar solvents are used relatively extensively, and the solvents are marketed and easily available. It is to be noted that these non-proton polar solvents can dissolve a large quantity of halogenated aromatic compounds as well as the solvents have low toxicity and risk.
• the amount of halogenated aromatic compounds was decreased to, for example, in the order of parts per million, the reaction speed of halogenated aromatic compounds and alkalis remarkably lowered.
• the above-mentioned non-proton polar solvents were used, it was confirmed that halogenated aromatic compounds were decomposed to the concentration of several ppm, and further to below the detection limit value (0.5 ppb or less), and that the compounds were substantially eliminated.
• non-proton polar solvents a mixture the principal component of which is a solvent selected from a group consisting of 1,3-dimethyl-2-imidazolidinone (hereinafter DMI), tetramethylene sulfone, and a mixture of 1,3-dimethyl-2-imidazolidinone and tetramethylene sulfone, and which contains one polar solvent selected from dimethyl sulfoxide, N-methyl pyrrolidone, tetramethyl urea, diethylene glycol and polyethylene glycol dimethyl ether, or two or more polar solvents selected from this group at a concentration of 35 % or less, can be used to effectively decompose the halogenated aromatic compounds.
• DMI 1,3-dimethyl-2-imidazolidinone
• tetramethylene sulfone 1,3-dimethyl-2-imidazolidinone
• tetramethylene sulfone 1,3-dimethyl-2-imidazolid
• Table 1 shows the treatment conditions and the remaining PCB amount after the treatment in the examples according to the present invention and the comparative examples. Note that in Table 1 when the remaining PCB amount is below the detection limit, it is represented by "N.D.” in the column of the remaining PCB amount.
• insulating oil hydrocarbon oil the principal component of which is non-aromatic hydrocarbon
• PCB gas chromatography mechanical spectrometer
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 13,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 800 in terms of mole ratio.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 25,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 720 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 90 ppb.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 17,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 90 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 80 ppb.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 12,500 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 7 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 50 ppb.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 48,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 16 in terms of mole ratio. Note that after the treatment was carried out for about 3 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 40 ppb.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 19,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 1500 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 30 ppb.
• the initial blending ratio of alkalis with respect to the whole reaction system corresponds to 27,500 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 16 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the concentration of the PCB in the oil layer had decreased to 20 ppb.
• the ratio of alkalis with respect to the chlorine amount in the PCB is 120 in terms of mole ratio, which is the same as or higher than that in Examples 1 to 7, a high concentration of PCB remained.
• the reason for this is that although the amount of NaOH is larger than that of PCB, the initial blending ratio of alkalis with respect to the whole reaction system is 2,000 mg/kg and is much lower than that in Examples 1 to 7.
• Examples 1 to 7 50 g of insulating oil containing PCB was added to the reaction system.
• Examples 8 to 10 an extremely small amount of insulating oil containing PCB was added to the reaction system. In these cases, since the quantity of the insulating oil is small, the insulating oil itself dissolves in the DMI layer. Therefore, the concentration of the PCB in the DMI layer was analyzed by a GC-MS after the reaction.
• the initial blending ratio of alkalis corresponds to 130,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 3 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the PCB concentration had decreased to 70 ppb.
• the initial blending ratio of alkalis corresponds to 160,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 2.6 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the PCB concentration had decreased to 25 ppb.
• the initial blending ratio of alkalis corresponds to 25,000 mg/kg
• the ratio of alkalis with respect to the chlorine amount in the PCB corresponds to 4 in terms of mole ratio. Note that after the treatment was carried out for about 2 hours under the same conditions, it was confirmed that the PCB concentration had decreased to 60 ppb.
• Examples 1 to 10 insulating oil containing PCB was added to the reaction system.
• Examples 11 to 14 instead of PCB being added to the reaction system directly, insulating oil was not added. In these cases too, the concentration of the PCB in the DMI layer was analyzed by a GC-MS.
• Halogenated aromatic compounds other than PCB can be decomposed in the same method, and polychlorinated terphenyl, polybrominated biphenyl and analogous compounds thereof, for instance, can be decomposed to the extent that the content may decrease to below the detection limit.
• alkalis NaO, Mg(OH)2 and others may be used as well as NaOH, KOH, CaOH and CaO.
• a non-proton polar solvent DMI was used, but tetramethylene sulfone or a mixture of DMI and tetramethylene sulfone may be employed as well. It is possible to use a mixture of these solvents and dimethyl sulfoxide, N-methyl pyrrolidone, tetramethyl urea, diethylene glycol or polyethylene glycol dimethyl ether. In this case, considering the alkali resistance at a high temperature, it is preferred that the blending ratio of dimethyl sulfoxide, N-methyl pyrrolidone, tetramethyl urea, diethylene glycol or polyethylene glycol dimethyl ether be 35 % or less.
• halogenated aromatic compounds and alkalis are contacted in a non-proton polar solvent at a temperature ranging from about 150° C to about 300° C for about 1 to about 10 hours, and the blending ratio of alkalis with respect to the whole reaction system when the reaction starts is set at 5,000 mg/kg or more. Therefore, in accordance with the present invention, it is possible to remove halogenated aromatic compounds such as PCB, which, even in small quantities, are directly hazardous to the human body with certainty and safely, to the extent that such compounds are rendered substantially harmless. Accordingly, it is possible to treat hydrocarbon oil containing PCB and others to the extent that such compounds are rendered substantially harmless.

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Fire-Extinguishing Compositions (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1994
  • 1994-04-22 JP JP12169094A patent/JP3247543B2/ja not_active Expired - Fee Related
• 1995
  • 1995-04-20 AU AU22672/95A patent/AU2267295A/en not_active Abandoned
  • 1995-04-20 WO PCT/JP1995/000785 patent/WO1995028993A1/ja not_active Application Discontinuation
  • 1995-04-20 EP EP95916026A patent/EP0711580A1/en not_active Withdrawn
  • 1995-06-27 TW TW84106595A patent/TW288009B/zh active

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