JP2002365273A - Method for measuring content of hardly decomposable halogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of measuring the content of a hardly decomposable halogen compound in a mixture containing insulating oil and the hardly decomposable halogen compound accurately, simply and rapidly. SOLUTION: In the method for measuring the content of the hardly decomposable halogen compound in the mixture containing the insulating oil and the hardly decomposable halogen compound by a chromatography technique, a column filled with an adsorbent is used before the content of the hardly decomposable halogen compound in the mixture is measured to separate the insulating oil and the hardly decomposable halogen compound from the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the content of hardly decomposable halogen compounds such as polychlorinated biphenyls (hereinafter abbreviated as "PCB") contained in insulating oil by chromatography. The present invention relates to a method for measuring the content of a hardly decomposable halogen compound.

[0002]

2. Description of the Related Art Persistent halogen compounds represented by PCBs and the like have become a problem as environmental pollutants. Therefore, it is necessary to detoxify the hardly decomposable halogen compound. In recent years, a detoxification (decomposition) method has been established.

[0003] Hardly decomposable halogen compounds exist in various forms in the environment. Among them, one of the problems as an environmental pollutant is a hardly decomposable halogen compound contained in insulating oil. This is detoxified in the state of a mixture containing insulating oil, but before and after the detoxification, for example, by using a gas chromatography technique, by measuring the content of the hardly decomposable halogen compound I have.

[0004] In order to detoxify a hardly decomposable halogen compound, the content of the hardly decomposable halogen compound must be known in advance. Further, after the treatment, it is necessary to measure the residual amount in order to confirm that the hardly decomposable halogen compound has been completely decomposed. In order to measure the content of the hardly decomposable halogen compound, an operation of separating a mixture containing the insulating oil and the hardly decomposable halogen compound in advance is necessary (cleanup).

Conventionally, methods for separating and purifying a hardly decomposable halogen compound from a mixture containing the hardly decomposable halogen compound include, for example, (1) a method of partitioning dimethyl sulfoxide and n-hexane, (2) a silica gel column treatment,
A method using normal phase column chromatography such as alumina gel treatment, activated carbon column treatment, Florisil column treatment, multilayer silica gel column (column packed with silica gel adsorbing sulfuric acid, potassium hydroxide, and silver nitrate in layers), (3) ) A method using reverse phase chromatography using an aqueous solution of dimethyl sulfoxide as a solvent, and (4) a chemical purification method such as a sulfuric acid treatment are known.

[0006] However, these methods are insufficient for separating the insulating oil from the hardly decomposable halogen compound.
In general, a plurality of operations (1) to (4) are performed in combination. For this reason, the process is long, the operation is complicated, and as a result, the recovery rate is reduced, and it takes a long time to separate and purify the hardly decomposable halogen compound and analyze it. There was a problem of cost.

In connection with the present invention, Japanese Patent Application Laid-Open No. Hei 10-5021
No. 07 discloses a porogen-modified styrene / divinylbenzene adsorbent and a styrene-crosslinked styrene / divinylbenzene adsorbent having a predetermined microporosity, mesoporosity and total porosity, of 200 to 1000 atomic mass units (U). )
It is described as being particularly useful for chromatographic separation of an organic adsorbate having a molecular weight of However, the target of separation is actually tryptophan or cephalosporin, and there is no description that it is useful for separating insulating oil and hardly decomposable halogen compounds as in the present invention.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a method for measuring the content of a hardly decomposable halogen compound in a mixture containing an insulating oil and a hardly decomposable halogen compound, which can be measured accurately, simply and quickly. It is an object to provide a method for measuring an amount.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, pre-treating the insulating oil and the hardly decomposable halogen compound with a column filled with an appropriate adsorbent. They have found that they can be separated and have completed the present invention.

That is, the present invention relates to a method for measuring the content of a hardly decomposable halogen compound in a mixture containing an insulating oil and a hardly decomposable halogen compound by a chromatographic technique. Before measuring the content of the compound, a step of separating the insulating oil and the hardly decomposable halogen compound from the mixture using a column filled with an adsorbent is provided. It is intended to provide a method for measuring a compound content.

The adsorbent used in the measuring method of the present invention is preferably a synthetic resin, and among the synthetic resins, a crosslinked resin is preferably used, and a divinylbenzene crosslinked resin or a crosslinked styrene resin is used. Is more preferable, and it is particularly preferable to use a divinylbenzene crosslinked styrene resin. Further, as the adsorbent, 1
It is preferable to use a synthetic resin of 0 to 200 mesh.

[0012] The measuring method of the present invention comprises a step of separating an insulating oil and a hardly decomposable halogen compound from the mixture using a saturated hydrocarbon solvent as an eluent using a column filled with the adsorbent. Preferably, among the hardly decomposable halogen compounds, aromatic halogen compounds,
It is particularly suitable for measuring the content of PCB. In addition, as a chromatography technique used in the measurement method of the present invention, a gas chromatography technique is preferably used.

[0013]

Embodiments of the present invention will be described below in detail. Examples of the halogen compound to be analyzed in the present invention include a halogen compound which is stable without being dehalogenated in an environment. Such halogen compounds include, for example, aromatic halogen compounds such as PCB, dioxins, polychlorinated benzofurans, polychlorinated benzene, and DDT; and alicyclic halogen compounds such as BHC. Among these, an aromatic halogen compound such as PCB contained in insulating oil is particularly preferable. Also,
The insulating oil is preferably an electric insulating oil described in JIS C2320-1993.

According to the present invention, there is provided a method for measuring the content of a hardly decomposable halogen compound contained in an insulating oil by a chromatography technique, wherein the insulating oil and the hardly decomposable halogen compound are adsorbed before the measurement. The method is characterized by providing an operation of separating using a column filled with the agent.

The material used for the adsorbent is not particularly limited as long as it has the ability to separate the insulating oil from the hardly decomposable halogen compound. For example, synthetic resin, activated alumina, silica gel, synthetic zeolite, activated clay, molecular sieve and the like can be mentioned. In the present invention,
Among these, synthetic resins are preferred.

As the synthetic resin, a homopolymer obtained from one kind of polymerizable monomer or a copolymer obtained from two or more kinds of polymerizable monomer can be used. As the polymerizable monomer,
For example, styrenes such as 4-methylstyrene, chlorinated styrene, brominated styrene, α-methylstyrene; acrylic acid, acrylamide, methyl acrylate, ethyl acrylate, n-propyl acrylate, butyl acrylate,
Acrylics such as acrylonitrile; methacrylic acids, methacrylamide, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, methacrylonitrile; and the like; divinylbenzene, vinyl alcohol, vinyl methyl ketone, etc. Vinyl compound; ethylene, propylene, 1-butene, 1-
Α-olefins such as pentene and 1-hexene; and dienes such as butadiene.

Specific examples of the synthetic resin include a styrene resin obtained from styrenes; an acrylic resin obtained from acrylics; a methacrylic resin obtained from methacrylics;
polyolefin resins obtained from α-olefins; butadiene resins obtained from dienes; and crosslinked resins.

Of these, the use of a crosslinked resin is preferred in the present invention. The crosslinked resin can be obtained, for example, by copolymerizing at least one of the above-mentioned homopolymers and at least one of the crosslinking agents, or by crosslinking the above-mentioned homopolymer or copolymer with a crosslinking agent. . The crosslinked resin is an insoluble porous polymer having a giant network structure, and has a large surface area and excellent adsorption ability.

As the cross-linking agent, a compound having a cross-linkable double bond in the molecule can be used, and examples thereof include a vinyl compound, a polyol, and a vinyl silane. Examples of the vinyl compound include divinylbenzene, vinyl methyl ketone, vinyl alcohol, vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, and methacrylic acid ester. Examples of the polyol include ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and acrylic polyol. Examples of the vinyl silane include vinyl trimethoxy silane, vinyl triethoxy silane, vinyl methyl dimethoxy silane, vinyl methyl diethoxy silane, vinyl ethyl diethoxy silane, vinyl ethyl diethoxy silane, isopropenyl trimethoxy lan, and isopropenyl triethoxy silane. And the like.

In the present invention, among these, excellent separation ability between the insulating oil and the hardly decomposable halogen compound (especially PCB), ease of availability, and availability of a saturated hydrocarbon solvent are preferred. Of the crosslinked resins, the use of a divinylbenzene crosslinked resin or a crosslinked styrene resin is preferred.

The divinylbenzene cross-linkable resin is obtained by copolymerizing one or more of the above-mentioned polymerizable monomers with divinylbenzene, or by cross-linking the above-mentioned homopolymer or copolymer with divinylbenzene. can get. The type of divinylbenzene is not particularly limited.
Divinylbenzene, 1,3-divinylbenzene, 1,4
-Divinylbenzene, 1,3-divinyl-4-methylbenzene and the like can be used.

The crosslinked styrene resin is obtained by copolymerizing at least one styrene and at least one crosslinking agent, or crosslinking a homopolymer or copolymer obtained from at least one styrene with a crosslinking agent. It is a resin obtained by: Examples of the crosslinking agent used here include the same compounds as those exemplified above. As styrenes, styrene, α-methylstyrene, 4-methylstyrene, 2-chlorostyrene, 3-chlorostyrene,
4-chlorostyrene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,3-dichlorostyrene, 2,4-dichlorostyrene, 2,3-dibromostyrene, 2,4-dibromostyrene, or the like is used. be able to. Among these, in the present invention, the use of a divinylbenzene crosslinked styrene resin is particularly preferred.

The surface area, porosity, pore size distribution, functional groups of the resin matrix and the like can be changed depending on the type of the crosslinked resin. The crosslinking type resin used in the present invention, the surface area usually 10~1,000cm ³ / g, preferably in the range of 150~1,000cm ³ / g, average pore size is usually 10～1,500A, preferably Is 30 to 200
ヘ, and the helium porosity is usually 40 to 60 vol.
l. % (0.6 to 1.2 cm ³ / g), and the porosity of mercury is usually 30 to 60 vol. % (0.5 to
1.2 cm ³ / g).

Specific examples of the synthetic adsorbent suitably used in the present invention include trade names: XAD-2, XAD-4, XA
D-7, XAD-8, XAD-9, XAD-20, XA
D-11, XAD-12, XAD-18, XAD-11
80, XAD-2000, Amberlite XAD such as XAD-2010 (Rome and Haas), trade names: CG-71, CG-161, CG-15
There are various types such as 1, CG-300, and CG-1000 (all manufactured by Ciba-Geigy).

There is no particular limitation on the particle size of the adsorbent, but the smaller the particle size, the higher the adsorbing ability, so that the adsorbent can be separated with a smaller amount of resin. The particle size of the resin used in the present invention is preferably in the range of 10 to 200 mesh, more preferably 50 to 200 mesh. As the resin used for the separation, it is also preferable to use a resin that has been pulverized and sieved, from the viewpoint that a more excellent separation effect can be obtained.

As a method used in the step of separating the insulating oil from the hardly decomposable halogen compound, for example, a separation column in which an adsorbent is packed in a column of an appropriate size is prepared, and the insulating column is placed therein. A method of adsorbing a mixture containing oil and a hardly decomposable halogen compound on the surface of an adsorbent, flowing an elution solvent, and collecting the eluate in predetermined volumes can be used. There is no particular limitation on the size of the column used,
The size of the column can be appropriately selected depending on the amount of the resin to be filled.

As a method for filling the column with the adsorbent,
For example, a method in which the adsorbent is suspended in an organic solvent, and the obtained slurry is filled in a column, and then replaced with a developing solvent. And the like.

The organic solvent is not particularly limited as long as it is a solvent stable to the adsorbent. However, it is preferable to use a solvent that can separate insulating oil and hardly decomposable halogen compounds using this column. For example, saturated hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone Solvents: Ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate and n-butyl acetate; Halogen solvents such as methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane; diethyl ether, tetrahydrofuran , 1,2-dimethoxyethane, dioxane and other ether solvents; N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethylimidazolinone, N-methylpyrrolidone and other amide solvents; methanol , Ethanol, n-propano , Isopropanol, alcohol solvents such as n- butanol;
Other organic solvents such as acrylonitrile and dimethylformamide can be used.

When the adsorbent is suspended in an organic solvent such as a hydrocarbon-based solvent, a solution obtained by adding a small amount of an alcohol-based solvent such as methanol or ethanol to a hydrocarbon-based solvent for the purpose of removing static electricity is used. Is preferred. The elution solvent may become cloudy after the column is filled with the adsorbent, but it is preferable to use the solvent for separation after the solvent has been sufficiently flowed through the column until the clouding disappears.

The amount of the adsorbent used is not particularly limited as long as it can sufficiently separate the insulating oil and the hardly decomposable halogen compound, but is usually 0.5 g to 10 g, preferably 1 g to 1 g of the mixture. The range is 5 g. After the adsorbent is filled in the column, the adsorbent is preferably left for 10 minutes to several hours and then used for the separation operation so that the adsorbent is sufficiently uniformly and tightly packed in the column.

When a mixture of an insulating oil and a hardly decomposable halogen compound is adsorbed on the surface of the adsorbent, the mixture may be adsorbed as it is, or n-hexane, beneene,
It may be adsorbed after dilution with a solvent such as toluene.

The elution solvent to be used is not particularly limited as long as it is a solvent capable of separating the insulating oil and the hardly decomposable halogen compound. However, since a concentration operation or the like is performed thereafter, a solvent having a relatively low boiling point (boiling point) is used. (About 50 to 150 ° C.) is preferred.

Examples of such a solvent include saturated hydrocarbon solvents such as n-pentane, n-hexane, n-heptane and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; acetone, methyl ethyl ketone, methyl Ketone solvents such as isobutyl ketone and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate and n-butyl acetate; methylene chloride, chloroform, carbon tetrachloride,
Halogen solvents such as 2-dichloroethane; ether solvents such as diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane, dioxane; N, N-dimethylformamide, N, N-dimethylacetamide;
Examples include amide solvents such as dimethylimidazolinone and N-methylpyrrolidone; alcohol solvents such as methanol, ethanol, n-propanol, isopropanol and n-butanol; and other organic solvents such as acrylonitrile and dimethylformamide.

In the present invention, among these, saturated hydrocarbons such as n-pentane, n-hexane, n-heptane, cyclohexane and the like are preferred from the viewpoints of separation and handling of insulating oil and the hardly decomposable halogen compound. Preferred are hydrocarbon solvents such as aromatic hydrocarbon solvents such as benzene, toluene and xylene, and n-pentane and n-pentane.
It is more preferable to use a saturated hydrocarbon solvent such as hexane, n-heptane and cyclohsan. The elution solvent can be flowed from the upper part of the column to the lower part under normal pressure or pressure, or can be sucked from the lower part of the column and flowed under reduced pressure.

After elution, every predetermined amount (for example, 5 ml to 5
(Each 0 ml), and fractions are collected, and all the fractions containing the hardly decomposable halogen compound are collected by detection means such as gas chromatography, and the content of the hardly decomposable halogen compound in the total amount is measured. . In this case, it is preferable that the insulating oil and the hardly decomposable halogen compound are completely separated, but a fraction in which the insulating oil and the hardly decomposable halogen compound are not completely separated may be contained.

The adsorbent is regenerated by treating it with, for example, an organic solvent, a base, an acid, water, hot water, etc.
Can be reused.

The means for measuring the content of the hardly decomposable halogen compound is not particularly limited as long as it is a means capable of quantifying the content of the hardly decomposable halogen compound. In the present invention, it is preferable to use a gas chromatograph mass spectrometer (GC-MS) in which gas chromatography and a mass spectrometer are combined from the viewpoints of convenience, detection accuracy, and the like.
As GC-MS, low resolution GC-MS, medium resolution G
There is no particular limitation on its performance such as C-MS and high-resolution GC-MS.

[0038]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. (Preparation of measurement sample) 2 ml of a solution of 4 g of trans oil dissolved in 10 ml of n-hexane and 2 ppm of PCB (K
C300: KC400: KC500: KC600 = 1:
A solution prepared by mixing 2 ml of a 1: 1: 1) n-hexane solution was prepared and used as a measurement sample.

(Preparation of separation column) Commercial styrene-
Divinylbenzene copolymer resin (XAD-2 resin, manufactured by Rohm and Haas Co.) in an untreated state or crushed and sieved to a predetermined size (65 to 150 mesh)
Was suspended in a mixed solvent obtained by mixing a small amount of ethanol with toluene for the purpose of removing static electricity, and the obtained suspension was filled in a glass column having a diameter of 15 mm and a length of 30 cm. . After filling the resin, 100 ml of n-hexane was flowed into the column, and the solvent was replaced to prepare a separation column. When the pulverized and sieved resin was filled, the elution solvent became cloudy immediately after filling, and the resin was sufficiently washed with n-hexane until the elution solvent became cloudy.

(Pretreatment operation) The measurement sample prepared above was introduced from the upper part of the separation column, and n-hexane was flowed as an eluent. For the measurement sample, the liquid was once drained from the lower part of the column to lower the liquid level, the inner wall of the column was washed twice with 2 ml of n-hexane, and then introduced into the upper surface of the packed resin. After the measurement sample was completely adsorbed on the resin surface, elution was performed by flowing n-hexane in a fixed amount. The flow rate of the eluent was approximately 0.05 ml / sec. The liquid eluted from the lower part of the column was fractionated as 10 ml (No. 1, 2) and 5 ml (No. 3, 4) fractions.

(Detection of Trans-Oil and PCB and Determination of Content) Next, the content of trans-oil and the content of PCB in each fraction were measured. Trans oil content is FID-GC, PCB content is EC
Each was detected and measured by D-GC. Table 1 summarizes the details of the resin used for the separation, the elution range of transformer oil (indicated as insulating oil in Table 1), and the elution range of PCB. No. 1 in Table 1 was used. The results of separation by the separation columns 1 to 4 are shown in FIGS. 1 (a) to 1 (d).

[0042]

[Table 1]

From Table 1 and FIG. 1, it was found that the insulating oil and PCB could be separated very easily and efficiently using XAD-2 which is a styrene-divinylbenzene copolymer resin. In addition, it was also found that the resin which was pulverized and sieved to have a mesh size of 65 to 150 was superior to the untreated XAD-2 resin in the ability to separate insulating oil and PCB.

(Measurement of PCB recovery rate)
No. in the table. Among the fractions of the eluate from the separation column of No. 4, a solution in which all the fractions containing PCB were collected (50 ml in total), and 50 mL of a 2 ppm PCB solution was used.
The solution diluted to 1 with n-hexane was analyzed by ECD-GC. As a result, the recovery rate of PCB was 94.1%.

According to the present embodiment, even when a low-concentration (2 ppm) PCB is contained in the transformer oil, the transformer oil and the PCB can be easily separated by a simple operation, and high accuracy can be obtained. It was found that the PCB concentration could be measured by the method.

[0046]

As described above, according to the measuring method of the present invention, the content of a hardly decomposable halogen compound in a mixture containing an insulating oil and particularly a low concentration of a hardly decomposable halogen compound can be accurately, simply, and easily measured. It has become possible to measure the content of a hardly decomposable halogen compound which can be measured quickly.

[Brief description of the drawings]

FIG. 1 shows No. 1 in Table 1. It is a figure showing the result of having separated using one separation column. In the figure, the horizontal axis represents the fraction (1
0 ml), and the vertical axis represents the trans-oil concentration (TO concentration (ppm)) or PC contained in the eluate.
Each represents the B concentration (ppm).

FIG. It is a figure showing the result of having separated using 2 separation columns. In the figure, the horizontal axis represents the fraction (1
0 ml), and the vertical axis represents the trans-oil concentration (TO concentration (ppm)) or PC contained in the eluate.
Each represents the B concentration (ppm).

FIG. It is a figure showing the result of having separated using the separation column of No. 3. In the figure, the horizontal axis represents the fraction (5
and the vertical axis represents the trans-oil concentration (TO concentration (ppm)) or PCB contained in the eluate.
Each represents a concentration (ppm).

FIG. FIG. 9 is a diagram illustrating a result of separation using a separation column of No. 4; In the figure, the horizontal axis represents the fraction (5
and the vertical axis represents the trans-oil concentration (TO concentration (ppm)) or PCB contained in the eluate.
Each represents a concentration (ppm).

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G01N 30/48 G01N 30/48 P // B01J 20/26 B01J 20/26 G Term (Reference) 4D017 AA03 BA04 CA13 CB01 DA03 4G066 AC12B AC14B AC17B AC35B BA09 BA20 BA23 BA26 CA33 DA07 DA09 EA01

Claims (9)

[Claims] 1. A method for measuring the content of a hardly decomposable halogen compound in a mixture containing an insulating oil and a hardly decomposable halogen compound by a chromatographic technique, wherein the content of the hardly decomposable halogen compound in the mixture is determined. Before measuring, using a column filled with an adsorbent, the step of separating the insulating oil and the hardly decomposable halogen compound from the mixture was provided, Measuring method. 2. The method according to claim 1, wherein a synthetic resin is used as the adsorbent. 3. The method according to claim 1, wherein a cross-linkable resin is used as said adsorbent. 4. The method according to claim 1, wherein a divinylbenzene crosslinked resin is used as the adsorbent. 5. The method for measuring the content of a hardly decomposable halogen compound according to claim 1, wherein a crosslinked styrene resin is used as said adsorbent. 6. The method for measuring the content of a hardly decomposable halogen compound according to claim 1, wherein a synthetic resin of 10 to 200 mesh is used as the adsorbent. 7. The method according to claim 1, further comprising the step of separating the insulating oil and the hardly decomposable halogen compound from the mixture using a saturated hydrocarbon solvent as an eluent using a column packed with the adsorbent. 7. The method for measuring the content of a hardly decomposable halogen compound according to any one of items 1 to 6. 8. The method according to claim 1, wherein said hardly decomposable halogen compound is an aromatic halogen compound. 9. The method for measuring the content of a hardly decomposable halogen compound according to claim 1, wherein a gas chromatography technique is used as said chromatography technique.