JP2001302553A - Method for treating organohalogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for decomposing an organohalogen compound in which the organohalogen compound is securely and reproducibly decomposed and detoxified with an alkali metal dispersion. SOLUTION: (1) The alkali metal dispersion is divided into plural portions and added for decomposing the organohalogen compound comprising reacting the organohalogen compound with the alkali metal dispersion in an organic solvent and (2) the alkali metal dispersion is divided into plural portions and added for decomposing the organohalogen compound comprising adding an active hydrogen compound immiscible with an organic solvent and reacting the organohalogen compound with the alkali metal dispersion in the organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for decomposing an organic halogen compound, for example, an organic halogen compound such as polychlorinated biphenyl (hereinafter abbreviated as PCB), by dehalogenating with an alkali metal. It is about the method.

[0002]

2. Description of the Related Art Conventionally, a method of decomposing an organic halogen compound by reacting an organic halogen compound with an alkali metal dispersion is known. For example, Japanese Patent Application Laid-Open No. 49-82570 by the present applicant discloses a method. , P which is an environmental pollutant
A method for treating environmental pollutants in which an organic solvent solution containing CBs or PCBs is heat-treated with an alkali metal in a dispersed state is described.
No. 6838 describes a method for decomposing a halogen compound by reacting a halogen compound with an alkali metal dispersion in an organic solvent by adding an active hydrogen compound which is not mixed with the organic solvent.

JP-A-59-20179 discloses that an organic halide dissolved in a hydrocarbon-based oil is reacted with molten sodium particles in a temperature range of 100 to 160 ° C. to form an organic halide. And Canadian Patent No. 1142551 describes a method for treating a biphenyl chloride composition by reacting the biphenyl chloride composition with an alkali metal under heating conditions.

[0004]

In the above-described conventional method for decomposing an organic halogen compound by reacting an organic halogen compound with an alkali metal dispersion, the organic halogen compound and the alkali metal dispersion are mixed at once. Only the method of reacting by heating or the like is described. Existing P
Organic halogen compounds such as CB are stored for a long time,
Depending on the state of storage, it may contain impurities such as oxides. Further, as another existence form, there is a low concentration in the transformer oil, and similarly, depending on the storage state, the transformer oil may be deteriorated by air oxidation or the like. When a PCB or the like having different properties depending on the storage state is decomposed by the above-described conventional technique, there is a problem that reproducibility may not be obtained due to impurities such as oxides.

An object of the present invention is to provide a method for dechlorination-decomposition treatment of an organic halogen compound using an alkali metal dispersion, which is more reproducible and more stable than conventional methods. It is to provide a decomposition method.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, it has been found that the above-mentioned problems can be solved by adding the alkali metal dispersion to be used in a plurality of divided portions. They have found that they can do this and have completed the present invention.

That is, the present invention provides (1) a method for decomposing an organic halogen compound and an alkali metal dispersion in an organic solvent, wherein the alkali metal dispersion is added in a plurality of portions. (2) a method for decomposing an organic halogen compound by reacting an organic halogen compound and an alkali metal dispersion in an organic solvent by adding an active hydrogen compound which is not mixed with the organic solvent; In the method for decomposing an organic halogen compound, wherein the alkali metal dispersion is added in a plurality of times, (3) the organic halogen compound and the alkali metal dispersion are mixed with the organic solvent in the organic solvent. In a method for decomposing an organic halogen compound in which an active hydrogen compound that is not mixed is added and reacted, an alkali metal dispersion is added in a plurality of portions. After method the decomposition of organic halogen compounds, characterized by adding an active hydrogen compound that does not mix with the organic solvent,

(4) The active hydrogen compound is water, methanol,
And (3) the method for decomposing an organic halogen compound according to any one of (1) to (3), wherein (5) the organic solvent is incompatible with the alkali metal. (1) to (4), wherein active aliphatic and / or aromatic hydrocarbons are used as a solvent.
A method for decomposing an organic halogen compound according to any one of the above,
(6) As aliphatic or aromatic hydrocarbons inert to alkali metals, kerosene, decalin, trans oil (JIS
1 selected from C2320-1993 transformer oil), heavy oil (described in JIS K2205), and washing oil
(5) The method for decomposing an organic halogen compound according to (5), wherein at least 80% of the alkali metal particles have a diameter of 30 μm or less as an alkali metal dispersion. (1) A method for decomposing an organic halogen compound according to any one of (1) to (6), wherein the alkali metal is sodium. (9) The organic halogen compound according to any one of (1) to (8), wherein the organic halogen compound is a hardly decomposable halogen compound containing polychlorinated biphenyls. The present invention relates to a method for decomposing a compound.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As the organic halogen compound in the present invention, for example, PCB, dioxins, polychlorinated dibenzofurans, polychlorinated benzene, DDT, B
HC can be used, and these organic halogen compounds may be used as they are, or they may be dissolved in a solvent and used as an organic halogen compound solution. As the solvent for dissolving the organic halide, an aliphatic hydrocarbon or an aromatic hydrocarbon which is inert to an alkali metal is preferable. For example, hexane, cyclohexane, benzene, kerosene, decalin, trans oil (JIS C 2320)
-Trans oil described in 1993), heavy oil (JIS K2)
205) or washing oils, which can be used alone or as a mixture.
It is preferable that the boiling point and the flash point of such a solvent be high, and among these solvents, trans oil can be particularly suitably used in terms of stabilizing the alkali metal dispersion. still,
The cleaning oil refers to a hydrocarbon-based solvent used for cleaning automobiles, electronic components, and precision equipment as a substitute for Freon, trichloroethane, kerosene, and the like. Since these solvents have a relatively high boiling point and a high flash point and are low in toxicity, they have excellent properties in terms of working environment and safety. Specifically, naphthesol (Nippon Oil Co., Ltd.)
JOMO MTF (manufactured by Japan Energy Co., Ltd.)
And the like. It is also possible to use kerosene, decalin, trans oil or the like contaminated with an organic halogen compound as a solvent.

In the present invention, examples of the alkali metal include sodium, potassium, lithium, cesium, and alloys thereof. In the present invention, the alkali metal is used in the form of a dispersion dispersed in a solvent. As the solvent used for preparing the alkali metal dispersion, an aliphatic hydrocarbon having a boiling point of 100 ° C. or higher and inert to the alkali metal is used. Or aromatic hydrocarbons, for example, toluene,
Xylene, kerosene, trans oil (JIS C232
0-1993), decalin, liquid paraffin, heavy oil (described in JIS K2205), washing oil or mixtures thereof. The solvent may be the same as or different from the solvent used for the above-mentioned decomposition reaction of the organic halogen compound. Also, a dispersant or an anti-agglomeration agent such as aluminum stearate may be added in advance, and when a solvent that stabilizes a high-viscosity alkali dispersion is used as a solvent, the dispersant or the anti-agglomeration agent may be used. Good.

The concentration of the alkali metal in the alkali metal dispersion can be arbitrarily selected.
% Is preferable. Further, the alkali metal dispersion can be prepared by a known method, for example, a method using a homogenizer can be applied. However, 80% or more of the alkali metal in the alkali metal dispersion is preferably 30 μm or less. Is preferably alkali metal particles having a diameter of 15 microns or less.

The active hydrogen compound used in the present invention is a compound which does not mix with the organic solvent used in the reaction.
There is no particular limitation, and specifically, water, lower alcohols, 2
Examples thereof include lower amines, lower carboxylic acids such as acetic acid, and the like, and these can be used alone or as a mixture of two or more. In particular, one or more compounds selected from the group consisting of water, methanol, ethanol, n-propanol, and isopropanol are preferred. The amount of the active hydrogen compound to be added is preferably 2 times or less, more preferably 0.1 to 1.5 times the mole of the alkali dispersion used.

The method for decomposing an organic halogen compound according to the present invention comprises the steps of:
The reaction can be carried out at a temperature in the range of from 200 ° C. to 200 ° C., but is preferably carried out in a temperature range from room temperature to the boiling point of the solvent.
When an active hydrogen compound is used, the reaction is preferably performed at a temperature ranging from room temperature to the boiling point of the active hydrogen compound.

The method for decomposing an organic halogen compound according to the present invention may be carried out in an amount of 1 to 500 times, preferably 1.05 to 200 times, 1 mole of a halogen atom of the organic halogen compound.
A molar alkali metal dispersion is used. In particular, when the reaction is carried out at a high temperature of 150 to 200 ° C., less than 2 moles, more preferably 1 mole to less than 2 moles, especially 1.1 mole to 1.6 moles, of the halogen atoms of the organic halogen compound. It is preferable to use an alkali metal dispersion of

When the reaction between the organic halogen compound and the alkali metal dispersion is carried out, if the concentration of the organic halogen compound in the reaction solution is too high, the concentration of the organic halogen compound in the reaction solution is increased by the polymer produced by dehalogenation from the organic halogen compound. Disperse state cannot be obtained, and conversely, if the concentration of the organic halogen compound is too low, the amount of alkali metal required for treatment of the organic halogen compound increases,
At the time when the alkali metal dispersion and the organic halogen compound are mixed, the concentration of the organic halogen compound in the whole mixed solution is 0.3% by weight or more, more preferably 1% by weight or more,
It is desirable that the content be 0% by weight or less, more preferably 15% by weight or less. Even when the decomposition target is an organic solvent contaminated with less than 0.3% by weight of an organic halogen compound, an appropriate alkali metal is used. Is not particularly limited. The reaction is desirably performed in an atmosphere of an inert gas such as argon or nitrogen for safety.

The mixing operation of the alkali metal dispersion and the organic halogen compound and the heating operation of the reaction solution for promoting the reaction include adding an organic halogen compound or a solution of the organic halogen compound to the heated alkali metal dispersion. A method in which an alkali metal dispersion and a solution of an organic halogen compound or an organic halogen compound are mixed and then heated; a method in which an alkali metal dispersion is added to the heated solution of the organic halogen compound; A method in which both of the halogen compound solutions are heated and then mixed and the like can be mentioned.

Further, when an active hydrogen compound is further used,
The order of addition can be arbitrarily selected, and among them, a method in which an organic halogen compound and an alkali metal dispersion are mixed, and an active hydrogen compound is added under heating and stirring is preferable. In the present invention, the alkali metal dispersion is
It is characterized in that it is added not every time but in multiple portions. This has the effect that impurities contained in the reaction system are removed by reacting with the alkali metal dispersion, and the subsequent reaction activity is not reduced.

The number of times is not particularly limited as long as it is at least two times, but it is preferable to carry out the reaction in two times in view of the reaction operation. The amount to be divided and added depends on the properties of the sample to be subjected to the decomposition reaction, but it is preferable that the amount be divided and added so as to at least remove the compound that deactivates the activity of the alkali metal dispersion. Specifically, in the case of adding twice, for example, a method of sequentially adding one half of the total amount to be added can be exemplified.

The order of addition of the organic halogen compound and the active hydrogen compound is not particularly limited as long as the alkali metal dispersion is added separately. For example, in a method in which an alkali metal dispersion is added in two equal portions, an organic halogen compound or a solution of an organic halogen compound is added to half of a heated predetermined amount of an alkali metal dispersion, and then a half of a predetermined amount of an alkali metal dispersion is further added. A method of adding a metal dispersion, a method of mixing an organic halogen compound or a solution of an organic halogen compound with half a predetermined amount of an alkali metal dispersion, heating the mixture, and further adding a predetermined amount of a half of an alkali metal dispersion; A method of adding a predetermined amount of a half alkali metal dispersion to a solution of a halogen compound, and further adding a predetermined amount of a half alkali metal dispersion, mixing an organic halogen compound and a predetermined amount of a half alkali metal dispersion. Every
Under heating and stirring, the active hydrogen compound is added, and further, a method of adding a predetermined amount of half of the alkali metal dispersion, mixing an organic halogen compound and a predetermined amount of half of the alkali metal dispersion, and heating and stirring, For example, a method of adding a half of the predetermined amount of the active hydrogen compound, further adding a half of the predetermined amount of the alkali metal dispersion, and adding a half of the predetermined amount of the active hydrogen compound can be exemplified.

The time spent mixing the alkali metal dispersion and the organohalogen compound can be reduced as long as the temperature rise due to the heat of reaction does not hinder the operation. The time required for the decomposition reaction is determined by the reaction temperature and the amount of the alkali metal dispersion used. However, if the time is too long, it is not preferable because the processing capacity is reduced. In addition, a batch-type (batch-type) or continuous-type reaction apparatus can be used as an apparatus used for performing such a reaction. The reaction apparatus provided with stirring means such as a stirring blade may be used. It is desirable to stir the liquid.

As a treatment method after the reaction between the organic halogen compound and the alkali metal is completed, a conventionally known method can be applied.
In the case of B or the like, first, the remaining alkali metal is converted into an active hydrogen compound in an equimolar amount or more with the remaining alkali metal, for example, alcohols such as methanol, ethanol, propanol and butanol, water, organic acids, or these. React with the mixture. The active hydrogen compound may contain an alkali metal halide and an alkali metal hydroxide. When a solid such as a polymer is generated by dehalogenation, the solid is separated into a liquid such as a solvent used by a method such as filtration or centrifugation. When an organic solvent that does not generate the solid and does not mix with the active hydrogen compound is used, the solvent and the active hydrogen compound such as water are separated by a liquid separation operation.

Next, if necessary, the active hydrogen compound is separated from the liquid component, and if necessary, treated with activated clay, the liquid component can be used again as a solvent. When using trans oil, it can be reused again as trans oil.

Hereinafter, the present invention will be described more specifically with reference to examples, but the scope of the present invention is not limited to these examples.

[0024]

Example 1 A 1 L reaction vessel was charged with 270 g of long-term stored trans oil containing 40 ppm of PCB. After the atmosphere in the reaction vessel was replaced with nitrogen, the solution was heated to 60 ° C., and while stirring and mixing, 2.5 g of a 10% by weight sodium metal dispersion (hereinafter abbreviated as SD) manufactured using fresh trans oil as a solvent (hereinafter abbreviated as SD) (Particle size 10 μm) was added little by little. Thereafter, the temperature was maintained at 60 to 65 ° C., and the reaction was carried out for a predetermined time shown in Table 1. Then, further 3.0 g of SD
And maintaining the temperature at 60-65 ° C.
g was added over 1 hour. Withdraw part of the mixture,
After pretreatment with a silica gel column, analysis was performed by gas chromatography with an ECD detector. Table 1 shows the results of two lots of the reaction repeated for the time after the first SD addition in order to check the reproducibility.

COMPARATIVE EXAMPLE 1 In Example 1, the addition of SD in two portions was repeated, except that the reaction was carried out in the same manner except that SD was added only once without dividing. Table 1 shows the results of the lot repetition reaction.

[0026]

[Table 1]

[0027]

As described above, in the treatment method of the present invention for dechlorinating and decomposing an organic halogen compound with an alkali metal dispersion, it is more efficient than conventional methods without being affected by the properties of the sample subjected to decomposition. Detoxification processing is now possible.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2E191 BA12 BA13 BB00 BC01 BC05 BD11 4H006 AA05 AC13 BA02 BB11 BB14 BB15 BB61 BC10 BC34 BD21 BE60

Claims (9)

[Claims] 1. A method for decomposing an organic halogen compound by reacting an organic halogen compound and an alkali metal dispersion in an organic solvent, wherein the alkali metal dispersion is added in a plurality of portions. Decomposition method. 2. A method for decomposing an organic halogen compound in an organic solvent, comprising adding an active hydrogen compound which is not mixed with the organic solvent to the organic halogen compound and the alkali metal dispersion. A method for decomposing an organic halogen compound, which is divided and added. 3. A method for decomposing an organic halogen compound, wherein an organic halogen compound and an alkali metal dispersion are reacted with an active hydrogen compound which is not mixed with the organic solvent in an organic solvent. A method for decomposing an organic halogen compound, which comprises adding an active hydrogen compound that is not mixed with the organic solvent after the addition. 4. The method for decomposing an organic halogen compound according to claim 1, wherein the active hydrogen compound is at least one selected from the group consisting of water, methanol and ethanol. 5. A method for decomposing an organic halogen compound according to claim 1, wherein the organic solvent is an aliphatic and / or aromatic hydrocarbon inert to an alkali metal. . 6. An aliphatic or aromatic hydrocarbon inert to an alkali metal, such as kerosene, decalin or trans oil (J).
Transformer oil described in IS C 2320-1993),
6. One or more kinds selected from heavy oil (described in JIS K2205) and cleaning oil are used.
The method for decomposing an organic halogen compound according to the above. 7. The alkali metal dispersion according to claim 1, wherein an alkali metal dispersion containing at least 80% of the alkali metal particles having a diameter of 30 μm or less is used as the alkali metal dispersion. A method for decomposing an organic halogen compound. 8. The method for decomposing an organic halogen compound according to claim 7, wherein the alkali metal is sodium. 9. The method for decomposing an organic halogen compound according to claim 1, wherein the organic halogen compound is a hardly decomposable halogen compound containing polychlorinated biphenyls.