JPH09253602A - Dechlorination method for organic chlorides - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe and economical dechlorination method for organic chlorides which are very difficult to be decomposed, which has no problem in respect of processes for disposal thereof. SOLUTION: In dechlorination wherein an organic chloride and alkaline are reacted with each other in an aprotic polar solvent at a temperature of 100-300 deg.C, excessive alkaline is used to implement a complete treatment and the excessive alkaline is solved and recovered by lower alcohol and the polar solvent is recovered to enhance safety, economy and practicalness of treatment processes, and deactivated oil can be used as fuel oil to plan an effective use of resources.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Dechlorination of specified toxic substances such as polychlorinated biphenyls (hereinafter abbreviated as PCB) and dioxin and other organic chlorine compounds for safe treatment is extremely important for industrial and environmental protection. is important.

[0002]

2. Description of the Prior Art Organochlorine compounds such as PCBs are now strictly stored, but over the years, the state of storage is not always perfect and safe and safe. An economical treatment method is desired.

Although many attempts such as a high temperature decomposition method and an alkali decomposition method have hitherto been made, a sufficient process has not been established due to restrictions such as processing standard problems and economical problems.

The present inventors have already conducted many years of research on alkali decomposition methods for halogenated aromatic compounds,
A remarkable invention has been completed (Japanese Patent Laid-Open No. 6-25691).
No. 7, JP-A-7-8572, JP-A-7-313620
issue). As a result of many more rigorous experiments, we have completed a new, more economical process. That is, an organic chlorine compound and an alkali are stirred and mixed in a polar solvent at 100 ° C. to 300 ° C. to carry out a reaction of dechlorination, and excess alkali is lower alcohol than solid content separated by filtering the reaction solution. The solvent of the filtrate is used as it is, or part or most of it is distilled and recovered for use in the next batch reaction, and the effluent of this step is treated with alkali. It has been found that it is possible to use only the hydrochloride and the dechlorination compound of the raw material organic chlorine compound, and it is possible to make all non-toxic general waste.

By this method, the alkali hydrochloride of the discharged matter and the dechlorination compound of the raw material organic chlorine compound are subjected to analysis, respectively, and it is shown that the undesirable components such as the organic chlorine compound are sufficiently removed. It is stored until confirmed and then reused or treated as municipal waste.

[0006]

The above-mentioned inventions of the present inventors can be said to be truly effective and excellent methods.
It is known that it is necessary to use an excess amount of alkali in order to obtain better results (JP-A-7-31362).
No. 0). Therefore, in order to further improve the practicability and the economical efficiency, the recovery of the excess alkali is an important issue together with the recovery of the polar solvent.

Further, in the conventional method, PC
Gas chromatographic mass spectrometry with high B concentration (GC-
There was a problem that it takes a long reaction time to reach the analytical detection limit or less in MS). One of the challenges is to shorten the reaction time.

[0008]

Therefore, the present inventors have found that the means for recovering alkali with a lower alcohol is very effective for the dechlorination method. That is, it was known that not only the alkali is sufficiently dissolved in the lower alcohol, but the alkali recovered in the lower alcohol has an effect of accelerating the reaction in comparison with the newly added alkali. The scientific explanation of the reaction mechanism and the like is currently being explored and will be elucidated.

In the present invention, what is more important is to control the water content in the lower alcohol to 10% or less, particularly preferably only the attached water content. It has been found that a large amount of water not only corrodes the apparatus but also dissolves the reaction product well, and thus inhibits the dehalogenation reaction near the end of the reaction. However, although the role of trace amount of water has not been clarified yet, it is considered that it plays some effective role in view of the distribution of reaction products.

The above method is also applicable to the treatment of hydrocarbon oils containing all concentrations of organochlorine compounds, such as PCB contaminated transformer oil or 100% PCB, with good results being obtained, and in some cases the hydrocarbons mentioned above. The oil is regenerated and can be reused.

In the present invention, the organic chlorine compound means PC
B, polychlorodibenzodioxin, polychlorodibenzofuran, or 1,2,3 trichloro-4'-nitro-biphenylether (hereinafter abbreviated as CNP) refers to a persistent organic chlorine compound, and alkali is caustic soda. -At least one compound selected from the group consisting of da, caustic potash, sodium lower alkoxide, potassium lower alkoxide, calcium hydroxide, calcium oxide, or a mixture of two or more. And, from the economical aspect, caustic soda is particularly preferable.

The polar solvent means dimethyl sulfoxide (hereinafter abbreviated as DMSO), 1,3-dimethyl-2-imidazolidinone (hereinafter abbreviated as DMI), dimethyl polyalkylene glycol, tetramethyl urea, N-. Methylpyrrolidone or the like, which contains 50% or more of one kind or a mixture of two or more kinds selected from these groups,
From the viewpoint of chemical safety and cost, DMSO, DMI,
50% of either dimethyl polyalkylene glycol
It is particularly preferable to use the solvent containing the above. If the content of these solvents is 50% or less, it becomes extremely difficult to completely remove chlorine.

A suitable temperature for stirring the organic chlorine compound and the alkali in the polar solvent is 100 ° C. to 300 ° C., but if the treatment temperature is 100 ° C. or less, it may take a very long time. When the temperature is 300 ° C. or higher, there is a risk of evaporation of the solvent or the organic chlorine compound and unexpected gelation due to side reaction. Especially when no additives are used, it is preferably carried out at 150 ° C to 250 ° C.

The reaction solution is filtered by centrifugation, pressure filtration,
Suction reduced pressure filtration and the like are suitable, and they are selected in consideration of the conditions such as the concentration of the starting organic chlorine compound and the viscosity of the system. The solvent in the filtrate can be recovered by distillation regardless of the embodiment as long as it is an efficient method such as vacuum distillation or vacuum thin film distillation. If it is convenient for the distillation residue to be in the form of a dry solid, it may be thoroughly distilled, the solid matter may be crushed and filtered, and the solid matter may be extracted and washed with a lower alcohol to recover the alkali, If it is a highly viscous fluid, several batches are combined and diluted with lower alcohol, then salts are filtered, and the alkali of the filtrate is analyzed and used as a raw material for the next batch reaction.

Conveniently in the present invention, if the polar solvent is chosen appropriately and the alkali is selected most economically, the reaction product and the inorganic salt are relatively insoluble in this solvent at room temperature, so that It can be separated by filtration without a troublesome procedure, and since only the alkali is easily dissolved in the lower alcohol, extraction and recovery can be advantageously performed.

As mentioned above, the fact that the alkaline substance recovered by the lower alcohol is much more reactive than the alkali initially used in this method is also an example of the superior point of this process.

In order to react PCB in the solvent of DMI in the presence of excess alkali, it is necessary to carry out batch reaction in the reaction vessel equipped with a stirrer shown in this method. Since this reaction reduces the PCB concentration to the ppb order, the reaction needs to proceed even when the PCB concentration is extremely low. or,
Even when treating high-concentration PCB, the PCB concentration becomes dilute as the reaction progresses. Therefore, in order for the reaction to proceed, the dilute PCB molecule and the alkali molecule must naturally come into contact with each other. For that purpose, it is necessary to increase the mixing degree of the liquid by shearing and associating the liquid. Therefore, static mixers are preferable because they are relatively small and can increase the mixing degree, and the energy consumption due to the pressure loss before and after this mixer is smaller than that of a stirrer when mixing, and therefore the mixing effect can be achieved with very little energy. May be obtained.

That is, in this reaction, it is considered that the alkali dissolved in DMI and PCB react in the liquid phase, and the dechlorination reaction proceeds. Therefore, to accelerate the reaction,
Maintaining a high alkali concentration dissolved in DMI, DM
In the presence of I, it is necessary to promote the association and contact between the alkali molecule and the PCB molecule. For the alkali used in the reaction, finely ground solid caustic soda or caustic potash is suspended in DMI to facilitate dissolution in DMI, and the alkali dissolved in DMI consumed in the dechlorination reaction is supplemented. There is a need. As a result of various studies on the method, a method of preparing a suspension in a mixing tank with a stirrer for mixing DMI and finely pulverized alkali, and directly supplying it to a liquid containing PCB in a reaction tank equipped with the stirrer for mixing In comparison, the method of extracting the liquid containing PCB from the reaction tank and passing it through the static mixer, then creating a circulation line for returning to the reaction tank, mixing the suspension at the inlet of the static mixer and passing it through the static mixer is more preferable. Dissolution of the alkali into the inside is promoted and the operation becomes easy. In this way, while supplying the suspension or after supplying it, the temperature of the reaction vessel is raised to keep the reaction temperature constant and the dechlorination reaction proceeds. Circulate through the mixer. By doing so, the dechlorination reaction can proceed and the intended purpose can be achieved.

To gain a better understanding of the process of the present invention,
Next, this process will be described with reference to the drawings. In addition, a typical flow chart of this process is shown in FIGS. 1, 2, 5, 6 and 7, FIG. 3 shows a case where there is no alkali and solvent recovery, and FIG. 4 shows alkali and solvent recovery. For some cases,
FIG. 8 shows an example of the material balance in the case of recycling DMI and recovered alkali.

In carrying out this process, it is not limited by the drawings that changes to the conditions of the raw materials or the place of execution to the extent that the essence of the flow is not changed are made without departing from the spirit of the present invention. It is self-evident that it is obvious and cannot be any negative factor in the superiority of this process.

[0021]

【Example】

Example 1 FIG. 1 shows an example in which the present invention is carried out. Reference numeral 9 is a relatively high concentration of PCB-containing insulating oil, which contains about 7% of PCB. 1 is a solvent (eg DM
I), 2 is an alkali (for example, caustic soda), 14 is DMI recovered in the still after the reaction, and 13 is a lower alcohol (for example, ethanol) in which alkali is dissolved. These are supplied to a jacketed reactor 5 equipped with a stirrer, heated to about 210 ° C. through a heating medium heated in the jacket 5 and reacted at normal pressure for 1 to 4 hours. The PCB in the reaction solution 20 is analyzed, and the reaction is terminated when the PCB is below the detection limit. This liquid is cooled to room temperature by passing a low-temperature refrigerant through the jacket 5, and the slurry-like liquid 20 containing the solid NaCl produced here is filtered by a filter (1) 6. The filtrate 10 is supplied to the distiller 8 to recover the solvent and reused in the next batch reaction. With respect to the remaining kettle 15 thus obtained, P
CB analysis was performed.

As a result, the content of PCB was less than the detection limit of 0.5 ppb (GC-MS actual result). The separated 11 cakes (1) were dissolved in the dissolution tank 19 and the unreacted alkali component contained in the cake was dissolved in ethanol.
Separation into cakes (2) of filtrates 13 and 12 with a filter (2). The filtrate 13 is ethanol that dissolves the recovered alkali,
Reuse in the next reaction by batch operation. Here, the two filters 6 and 7 are shown separately, but the same one may be used separately by a batch operation without dividing into two. FIG. 3 is a case of decomposing a relatively high concentration PCB-containing insulating oil, and shows an example of an outline of the material balance of the first batch operation in which alkali and solvent are not reused.

Example 2 FIG. 4 shows a case of decomposing a relatively high-concentration PCB-containing insulating oil, and shows an example of a material balance for an example in which an alkali and a solvent are reused. The temperature and operating conditions of each part are almost the same as those shown in Example 1.

Embodiment 3 FIG. 2 shows another example for carrying out the present invention. 9 is a relatively low concentration PCB-containing insulating oil, 2
It contains about 0 ppm of PCB. The low concentration referred to here means a dilute PCB concentration in which precipitation of reaction products is relatively small even after cooling after the reaction. Other numbers are shown in Figure 1.
They have the same or substantially the same functions or properties as those described in the above. The operation in the stirring reaction tank is the same as in Example 1, but after the reaction is complete, the reaction solution contains no solid matter other than the finely ground caustic soda of this reaction, so it is supplied to the distiller as it is, and the solvent is recovered. However, the remaining kettle is the dissolution tank 1.
At 9, the unreacted alkali is dissolved in ethanol. It is divided into an oil phase and an alcohol phase in which an alkali is dissolved in a separating tank, and the alcohol phase is reused for the next batch reaction by a batch operation. The oil phase is washed with water, neutralized with an acid, and separated into an oil phase and an aqueous phase. As a result of PCB analysis of the oil phase obtained here, it was found that PCB was removed up to the detection limit of 0.5 ppb or less.

Example 4 FIG. 5 shows an example of a method for supplying raw materials to a reaction tank. The numbers shown here are the same as those in FIGS. These raw materials are mixed well in advance in the mixing tank, and then mixed into the reaction liquid circulation line 30 using the supply pump 32. The mixed reaction circulating liquid is completely mixed by the static mixer 29, returned to the reaction tank 4 with a stirrer, and further stirred by the stirrer 3.

Since this static mixer draws out a part of the liquid subjected to the stirring operation in the reaction tank, it is necessary to select a mixing strength in the static mixer that is stronger than the mixing strength in the stirring tank. Of course.

Since the alkali is supplied as a solid and is heavier than the specific gravity of the liquid, a part of the alkali precipitates at the bottom of the stirring reaction tank, and in the case of a reactor mainly using centrifugal stirring, the suspended state cannot be maintained. In particular, the contact with the reaction solution tends to be incomplete. As a method for improving this, it is possible to maintain and improve the suspension state in the reaction solution by extracting the precipitated solid content from the bottom and passing it through a static mixer. This operation is continuously performed even after supplying the raw materials.

Further, reference numeral 35 in the drawing is a heater for heating the static mixer portion, which compensates for the temperature drop due to heat loss in the circulation line and also raises the temperature as necessary, thereby also having the effect of increasing the reaction rate. Is able to.

When the reaction is carried out at a reaction temperature of 210 ° C. in a stirring reaction tank at normal pressure by such a method, as a result of comparing the method of supplying raw materials directly to the reaction tank and the method of supplying by a static mixer, 1) Compared to the direct supply method, the method of providing the mixing tank facilitated the charging operation. (2) At the bottom of the reaction vessel, the precipitation of the alkali solids at the bottom was prevented, and the suspended state was maintained, whereby the effect of promoting the reaction was obtained. (3) As a result, when the static mixer was used, the intended purpose was achieved in about 80% of the time required for the direct method.

Example 5 Example 3 shows an example of treatment of relatively low concentration PCB-containing insulating oil by the process flow shown in FIG. Here, in addition to the reaction tank, a distiller is separately provided to collect the solvent. When DMI is used as a solvent, its boiling point is 225.5 ° C. at atmospheric pressure, whereas that of insulating oil is 250 to 470 ° C., so that it can be easily separated by simple distillation. Can also be used. In this way, the process can be simplified, the equipment cost can be saved, and the processing cost can be reduced. This example is shown in FIG.

The distillation may be carried out under reduced pressure in consideration of the temperature of the heating source. For example, when the absolute pressure is 40 mmHg, the distillation is 150
It is possible to distill and separate DMI from the reaction solution at ° C.

In this process, PCB can be removed from TFO (insulating oil) very economically by reusing the recovered DMI and alkali dissolved in alcohol, and the PCB can be detoxified by removing it. The insulating oil can be reused as fuel oil. The process flow of this example is shown in FIG. 7, and the material balance at that time is shown in FIG.

Here, the recovered DMI is recycled 15 times, and the alkali recovered with the modified ethyl alcohol is 15 times.
This is an example of being able to recycle more than once.

First, using new DMI and new caustic soda, PC in new TFO containing 80 ppm PCB.
B is dechlorinated. The liquid after this is TFO phase and D
The phase is separated into the MI phase (solid liquid phase containing solid of caustic soda), and this DMI phase (containing caustic soda) is used again in the reaction. TFO 1.00 containing 80 ppm PCB
Add 0 g DMI 1,000 g caustic soda 60 g,
Put in the reaction tank. The temperature is raised to 200 ° C., and the mixture is vigorously stirred for 2 hours. The residual concentration of PCB in the system after 2 hours is 0.5 pp
b (below the detection limit = ND).

The reaction solution is first phase-separated, and the TFO phase and DM are separated.
Separated into Phase I. At this time, if necessary, a small amount of a lower alcohol (containing 10% or less of water) may be added to accelerate the reaction and phase separation. To further assist the phase separation, a simple filtration is performed once (pressurization or depressurization), and then the phase separation is performed. TF
The O phase is washed with water, mixed with heavy oil and reused as fuel oil. The DMI in the DMI phase and caustic soda are reused to decompose the PCB in fresh TFO. This one
Repeat 5 times. A small amount of DM is needed for the reaction.
I and a small amount of caustic soda may be added. The DMI phase containing caustic soda, reaction products and sodium chloride is usually first filtered with a centrifugal filter to separate solid and liquid.
DMI is recovered by distilling the liquid phase filtrate. This DMI
Is recycled to the next reaction. On the other hand, for the solid phase component (cake), the amount of modified ethyl alcohol that sufficiently dissolves the caustic soda is added to recover the residual caustic soda after the use in the dechlorination reaction. At this time, most of the reaction product and the sodium chloride formed are hardly dissolved in the modified ethyl alcohol, and therefore exist as a solid. These mixtures are filtered with a centrifugal filter to separate solid and liquid. Most of the caustic soda is transferred to the liquid phase filtrate and recycled for the next reaction. The recovery rates of DMI and alkali were 99% and 91%, respectively.

Example 7 The material balance of the process is almost the same as in Example 6, except that triethylene glycol dimethyl ether (boiling point 216 ° C.) or tetraethylene glycol dimethyl ether (boiling point 27) is used as a solvent instead of DMI.
(5.3 ° C.) and reacted using caustic soda as the alkali, and is an example relating to the process of recycling 15 times. Hydrous methanol (containing 10% water) is used in the phase separation of the solvent and TFO.

[0037]

INDUSTRIAL APPLICABILITY As described above, the present invention relates to a process for dechlorinating and detoxifying an organic chlorine compound extremely economically. Therefore, by carrying out the present invention, economically and safely In addition, it can contribute to the improvement of the environment.

[0032]

[Brief description of drawings]

FIG. 1 is a diagram showing a representative flow sheet of this process.

FIG. 2 is a diagram showing a representative flow sheet of this process.

FIG. 3 is a flow test of this process in which alkali,
It is a figure which shows an example of the material balance about the case where a solvent is not collect | recovered.

FIG. 4 is a flow test of this process in which alkali,
It is a figure which shows an example of the material balance about the case where a solvent is collected.

FIG. 5 is a diagram showing an example of a method for supplying a raw material to a reaction tank in this process.

FIG. 6 is a diagram showing an exemplary flow chart of this process.

FIG. 7 is a diagram showing reuse of detoxified insulating oil as fuel oil in the flow test of this process.

FIG. 8 is a diagram showing a material balance when DMI and recovered alkali are recycled 15 times and reused as fuel oil in the flow test of this process.

[Explanation of symbols]

[Reference numeral in FIG. 1] 1 DMI 2 caustic soda 3 stirrer 4 reaction tank 5 jacket 6 filter (1) 7 filter (2) 8 distiller 9 PCB-containing insulating oil 10 filtrate (1) 11 cake (1) 12 cake ( 2) 13 Filtrate (2) 14 Collected DMI 15 Remaining kettle 16 Recovered ethanol 17 Ethanol 18 Makeup ethanol 19 Dissolution tank 20 Reaction solution 36 Recovered DMI storage tank 37 Condenser 38 Condenser [Code in FIG. 2] 21-1 Separation tank 21-2 Separation tank 22 Ethanol / NaOH 23 Water washing / neutralization tank 24 Oil phase 25 Water phase 26 Water 27 Acid [reference numeral in FIG. 5] 28 Circulation pump 29 Static mixer 30 Circulation line 31 Reaction supply liquid pipe 32 Supply pump 33 Stirrer 34 Mixing tank 35 Heater for heating (Numbers other than the above are common to those shown in Figs. (Reference numeral in FIG. 7) 39 adjusting tank 40 cooling tank 41 filtrate receiving tank 42 distillate (DMI) receiving tank 43 separator 44 high pressure insulating oil (TFO) receiving tank 45 pot residual liquid receiving tank 46 alkali dissolution tank 47 alcohol Supply tank 48 Alkali-containing alcohol solution storage tank 49 Alkali supply tank 50 Cake storage tank 51 Raw material (PCB-containing TFO) supply tank 52 Solvent (DMI) supply tank 53 New alkali supply tank 54 Stirring drive motor 55 TFO Water washing tank 56 TFO water washing receiving tank 57 TFO heavy oil mixing tank (Numbers other than the above are common to those shown in FIGS. 1 and 2)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07B 63/02 B09B 3/00 ZAB (72) Inventor Fumio Tanimoto Shimogamo Morimoto-cho, Sakyo-ku, Kyoto Prefecture Kyoto Prefecture 15 In the Institute for Industrial Development Science (72) Inventor Kiyohiko 99 Kiyohiko Shimogamomorihonmachi, Sakyo-ku, Kyoto City, Kyoto Prefecture In the Institute for Industrial Development Science (72) Mitsuhiko Nakamura Fuse, Kashiwa City, Chiba Prefecture Shinmachi 4-8-6 (72) Inventor Tsuneo Yano 413-14 Kawadera, Hanno City, Saitama Prefecture (72) Inventor Mitsutoshi Higashiuchi 4-4-4-304 Kitakasai, Edogawa-ku, Tokyo (72) Inventor Door ▲ Ma ▼ Toshiko, 4-1, Egasaki-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Energy and Environmental Research Laboratory, TEPCO (72) Inventor Koichi Furuhashi 1-1, Oike-cho, Kosai-cho, Koga-gun, Shiga Prefecture In the company Neos

Claims (12)

[Claims] 1. An organic chlorine compound and an excess of alkali,
In an aprotic polar solvent (hereinafter referred to as polar solvent), 1
In the step of performing a dechlorination reaction (hereinafter referred to as the main reaction) in the reaction vessel by stirring and mixing at 00 ° C to 300 ° C, excess unreacted alkali is separated and recovered from the reaction product after the main reaction. The product of this step is reused in this reaction and the polar solvent is used as it is, or a part or most of it is separated and recovered and reused in this reaction to dechlorinate the alkali hydrochloride and the starting organic chlorine compound. A method for dechlorinating an organic chlorine compound, which comprises converting the compound into a compound. 2. When the solid content is produced after cooling the reaction solution obtained by the dechlorination reaction (hereinafter referred to as the reaction solution) because the concentration of the organic chlorine compound participating in the reaction is relatively high, excess unreacted alkali is removed. When separating and collecting from the reaction product, after cooling the reaction liquid, the generated solid content is separated, and the alkali contained in the solid content is dissolved in a lower alcohol and separated and collected. A method for dechlorinating an organic chlorine compound as described. 3. When the concentration of the organochlorine compound involved in the reaction is relatively low and a relatively small amount of solid is produced after cooling the reaction solution, the reaction is performed when the unreacted alkali is separated and recovered from the reaction product. The product is characterized in that the product is distilled as it is without cooling to recover the polar solvent, and the alkali contained in the residue is dissolved in the lower alcohol and separated and recovered.
A method for dechlorinating an organic chlorine compound as described. 4. When the concentration of the organochlorine compound involved in the reaction is relatively low and the amount of solids produced after cooling the reaction solution is relatively small, the cooled reaction solution is allowed to stand and the polar solvent and dechlorination compound are left. The reaction liquid containing the following (hereinafter referred to as the present reaction liquid) is separated into two phases, the polar solvent is recovered and reused in the next main reaction, and is used for another purpose after the main reaction. 1. A method for dechlorinating an organic chlorine compound according to 1. 5. The method according to claim 4, wherein when separating the polar solvent and the two phases after the main reaction, a lower alcohol used for recovering an alkali is added to rapidly separate the polar solvent and the main reaction solution. The method for dechlorinating an organic chlorine compound according to claim 1, wherein the method is dechlorination. 6. The method according to claim 2, wherein the polar solvent in the residual liquid obtained by separating the solid matter is reused in this reaction as it is, or after being partially or largely recovered by distillation. The method for dechlorinating an organic chlorine compound according to claim 1. 7. The lower alcohol used for separating and recovering an alkali according to claim 2, wherein the water content is 1.
The dechlorination of an organochlorine compound according to claim 1, which is a mixture of at least one type or two or more types selected from the group consisting of 0% or less of C1 to C4 alcohols. Method. 8. The polar solvent is sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone,
The dechlorination of the organochlorine compound according to claim 1, which comprises 50% or more of at least one selected from the group consisting of dimethylpolyalkylene glycol, tetramethylurea and N-methylpyrrolidone, or a mixture of two or more thereof. Chlorination method. 9. The method according to claim 2, including an alkali that is dissolved and recovered in a lower alcohol and is reused in this reaction (hereinafter referred to as a recovered alkali), and an amount of alkali that supplements the amount consumed in dechlorination. Most of the lower alcohol is distilled out of the system by supplying it to the reaction tank and raising the temperature to start the reaction together with the polar solvent, and this is recovered and reused for the next alkali recovery after the main reaction. The method for dechlorinating an organochlorine compound according to claim 1, wherein the method is for dechlorination. 10. An organic chlorine compound to be supplied to a reaction tank, a recovered alkali to be reused, an alkali to be newly supplied, a polar solvent to be newly supplied, and a recovery polar solvent to be reused,
The method for dechlorinating an organic chlorine compound according to claim 1, wherein two or three or more of them are mixed in advance and supplied to the reaction tank. 11. The method for dechlorinating an organic chlorine compound according to claim 1, wherein the premixing method according to claim 10 uses a mixing tank with a stirrer and a static mixer alone or in combination. 12. The method of using a mixing tank with a stirrer according to claim 11, wherein after the recovered polar solvent and a part of the polar solvent to be newly supplied are charged into the mixing tank with a stirrer, solid caustic soot is finely ground as an alkali. -Slurry by mixing da or caustic potash and recovered alkali, and then withdrawing a part of the mixed solution of polar solvent and organochlorine compound that has already been supplied to the reaction tank, and mixing with it to supply to the reaction tank. The method for dechlorinating an organic chlorine compound according to claim 1, characterized in that.