JPH1128443A - Method for decomposing halogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently execute detoxicating treatment without involving org. chlorine component in the produced polymer by allowing org. halogen compd. in a specified concn. to react with dispersed alkali metal in decahydronaththalene or the solvent containing the decahydronaththalene in a specified concn. SOLUTION: The org. halogen compd. in 1-20 wt.% concn. per total reaction soln. is allowed to react with the dispersed alkali metal in the decahydronaththalene or the solvent containing the decahydronaththalene in >=15 wt.% concn. per total reaction soln. The org. halogen compd. is PCB, dioxins, dibenzofurans, polychlorinated benzene, etc. Sodium, potassium, lithium, etc., are exemplified as the alkali metal used for the alkali metal dispersion, and the dispersion in which these alkali metals are dispersed in an inert org. solvent such as aliphat., arom. hydrocarbon such as kerosine, trans oil and benzene as particles having a diameter of <=50 μm, preferably <=15 μm is used as the dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic halogen compound such as polychlorinated biphenyl (hereinafter referred to as PCB).
Abbreviated as above) and the like, and a method of dehalogenating and decomposing an organic halogen compound with an alkali metal.

[0002]

2. Description of the Related Art JP-A-49-82570, JP-A-59-20179, and the like disclose methods of detoxifying an organic halogen compound by reacting an organic halogen compound with an alkali metal dispersion. The processing of the PCB by these methods is as follows:
It detoxifies PCB and detoxifies it by polymerizing it.

[0003] When disposing of the produced polymer, incineration is conceivable. At this time, if chlorine components remain in the polymer, harmful organic chlorine compounds such as PCB and dioxin may be formed again. is there. Therefore,
In the detoxification treatment by dechlorination, it is necessary to reduce the chlorine component in the produced polymer as much as possible.

In the case of JP-A-59-20179, there is no description about a chlorine component in the produced polymer. In the case of JP-A-49-82570, although the dechlorination rate is almost 100% according to the measurement of the amount of chloride ions formed, the reaction rate is low and the efficiency is poor when no alcohol or the like is added as an activator. Was.

[0005]

SUMMARY OF THE INVENTION In a method for dehalogenating and decomposing an organic halogen compound with an alkali metal dispersion, the present invention provides an efficient detoxification method which does not leave an organic chlorine component in a polymer to be produced. I do.

[0006]

According to the present invention, there is provided a method for preparing decahydronaphthalene or a solvent containing 15% by weight or more of decahydronaphthalene in the entire reaction solution in a concentration of 1 wt% to 20 wt% in the entire reaction solution. A method of dehalogenating and decomposing an organic halogen compound, which comprises reacting an organic halogen compound having a concentration of 1 with an alkali metal in a dispersed state.

The organic halogen compound in the present invention can be widely applied to organic halogen compounds such as PCB, dioxins, dibenzofurans, polychlorinated benzene, and methylene chloride.

The alkali metal used in the alkali metal dispersion includes sodium, potassium, lithium, cesium, and alloys thereof, and among them, sodium is usually used. As a dispersion, these alkali metals are dissolved in an inert organic solvent such as an aliphatic or aromatic hydrocarbon such as kerosene, trans oil, benzene, xylene, tetralin, or decahydronaphthalene in a concentration of 50 μm.
Hereinafter, those dispersed as particles having a diameter of preferably 15 μm or less are used.

[0009] The alkali metal dispersion can be produced by a known method. For example, a method using a homogenizer can be applied.

As the solvent used in the reaction, the same solvents as those used for producing the above-mentioned alkali metal dispersion can be used.

The present invention is carried out in a solvent having a concentration of 15% by weight or more, preferably 50% by weight or more of decahydronaphthalene alone or in a concentration of decahydronaphthalene in the whole reaction solution.

When a single solvent of decahydronaphthalene is used, the solvent used for producing the alkali metal dispersion is naturally decahydronaphthalene. When performed in a mixed solvent, decahydronaphthalene is a solvent at the time of production of the alkali metal dispersion,
A solvent for dissolving the organic halogen compound or a reaction solvent may be added to the reaction system, and any method may be used.

The amount of the solvent used in the reaction is an amount necessary for the concentration of the organic halogen compound in the whole mixed solution to be from 1 wt% to 20 wt% when the alkali metal dispersion is added. Preferably 1 wt% to 15
wt%. The order of addition of the alkali metal dispersion and the organic halogen compound is not particularly limited, and after dissolving the organic halogen compound in the solvent, the alkali metal dispersion may be added, and the alkali metal dispersion is diluted and dispersed in the solvent. Later, an organic halogen compound may be added.

The amount of the alkali metal dispersion added is 2 to 50 times, preferably 2.5 to 10 times, the molar amount of sodium relative to the halogen atom of the organic halogen compound.

The temperature at which the organic halogen compound is decomposed is not limited, but a lower temperature tends to increase the reaction time. Usually, the reaction is carried out in a temperature range from room temperature to the boiling point of the solvent used, but this is not the case when the decomposition treatment is performed under pressure. However, since it is dangerous if the reaction temperature is too high, the reaction is preferably performed at 50 ° C to 110 ° C.
The reaction time is determined by the temperature at which the reaction is carried out and the amount of the alkali metal dispersion used. There is no limitation on the stirring of the reaction solution during the reaction, but it is preferable to stir using a stirring blade or the like.

The present invention is preferably carried out in an atmosphere of an inert gas such as argon or nitrogen for safety.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described by way of examples.
The present invention is not limited to this.

Example 1 5.09 g of KC400 which is a PCB having an average chlorine addition number of 4 was placed in a 200 ml reaction vessel.
It was charged and dissolved with 64.83 g of decahydronaphthalene. After the atmosphere in the reaction vessel was replaced with nitrogen, 34 g of a 40% metal sodium dispersion prepared using decahydronaphthalene as a solvent was added, followed by stirring and mixing. The mixture was heated to 70 ° C. and maintained at that temperature for 2 hours. A part of the mixed solution was withdrawn, and the supernatant was subjected to a pretreatment with a silica gel column and analyzed by gas chromatography with an ECD detector.
ppm). The mixed solution was withdrawn, accurately weighed, and the remaining metallic sodium was decomposed with water, and then the produced polymer was separated by filtration. The recovered polymer and decahydronaphthalene layer were sufficiently washed and extracted with water. All the water used was collected, the combined weight was measured, a part of the water was withdrawn and weighed, and neutralized with nitric acid.
Potentiometric titration was performed with a 1 mol / l silver nitrate aqueous solution. As a result of calculating the generation amount of chlorine ions by calculation, it was 98% of the amount of chlorine contained in the PCB.

Example 2 While replacing the inside of a 200 ml reaction vessel with nitrogen, 33 g of a 40% metal sodium dispersion prepared using decahydronaphthalene as a solvent was charged.
Diluted with 50.4 g of decahydronaphthalene. A solution obtained by diluting 5.056 g of KC400 with 20.36 g of decahydronaphthalene was added dropwise thereto, and the mixture was maintained at 70 ° C. for 4 hours. When the PCB concentration was measured by the same method as in Example 1, the PCB concentration was below the detection limit. When the amount of chloride ion generation was measured in the same manner as in Example 1, the amount of chloride ion generation was almost 100% of the amount of chlorine contained in the PCB.

Example 3 KC was added to a 200 ml reaction vessel.
4004 was charged and dissolved with 59.79 g of decahydronaphthalene. After the atmosphere in the reaction vessel was replaced with nitrogen, 30.63 g of a 40% metal sodium dispersion prepared using kerosene as a solvent was added thereto, followed by stirring and mixing. The mixture was heated to 110 ° C. and maintained at that temperature for 3 hours. When the PCB concentration was measured by the same method as in Example 1, the PCB concentration was below the detection limit. When the amount of chloride ion generation was measured in the same manner as in Example 1, the amount of chloride ion generation was almost 100% of the amount of chlorine contained in the PCB.

[Comparative Example] KC4 was added to a 200 ml reaction vessel.
Was charged with 65.11 g of kerosene. After the atmosphere in the reaction vessel was replaced with nitrogen, 34 g of a 40% metal sodium dispersion prepared using kerosene as a solvent was added thereto, followed by stirring and mixing. Mixture at 70 ° C
And maintained at that temperature for 4 hours. When the PCB concentration was measured by the same method as in Example 1, the PCB concentration was below the detection limit. When the amount of chlorine ion generation was measured by the same method as in Example 1, the amount of chlorine ion generation was about 89% of the amount of chlorine contained in the PCB, which was lower than that in Examples 1, 2 and 3. It was a low value.

[0022]

According to the present invention, in a method for dechlorinating and decomposing an organic halogen compound with an alkali metal dispersion, the present invention provides an efficient detoxification method in which an organic chlorine component does not remain in a produced polymer.

Claims (3)

[Claims] 1. Decahydronaphthalene or decahydronaphthalene having a concentration of 15% in the whole reaction solution.
a dehalogenation decomposition of an organic halogen compound characterized by reacting an organic halogen compound having a concentration of 1 wt% to 20 wt% with respect to the whole reaction solution and an alkali metal in a dispersed state in a solvent containing not less than wt%. Method. 2. The method according to claim 1, wherein the alkali metal is sodium. 3. The method according to claim 1, wherein the organic halogen compound is polychlorinated biphenyl.