JP2006052285A - Debromination method of bromine-containing organic compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a debromination method of high efficiency and of a bromine-containing organic compound without generating hydrogen bromide by thermal decomposition or reflux, and, thereby, to make debromination of high efficiency easy without generating corrosive bromine-containing gas. <P>SOLUTION: The method comprises electrolyzing a bromine-containing organic compound in an organic solvent by using a metal containing zinc as at least one of electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for debromination of an organic compound containing a bromine atom. More specifically, the present invention relates to a method for debromination by electrolyzing an organic compound containing a bromine atom in an organic solvent using a metal containing zinc for at least one electrode.

  In order to impart flame retardancy to an organic compound, a halogen-based flame retardant is particularly effective. However, when these wastes are incinerated, toxic gases such as hydrogen halides, alkyl halides, and dioxins may be generated, and therefore various dehalogenation techniques have been studied.

  Japanese Patent Laid-Open No. 48-39572 discloses a technique in which chlorine-containing synthetic resin waste is subjected to low-temperature carbonization at 350 to 400 ° C., chlorine is removed as hydrogen chloride, and absorbed into water to form hydrochloric acid. Japanese Patent Application Laid-Open No. 57-174187 discloses a device for recovering heavy oil and light oil from a cracked gas generated by thermally decomposing a resin by a dry packed bed and neutralizing hydrogen chloride gas by a limestone bed. ing. If this apparatus is used, the produced | generated hydrogen chloride can be absorbed more efficiently than the case where it absorbs with water. These methods and devices generate hydrogen halide gas in a heating furnace and collect it. The corrosive nature of hydrogen halide greatly increases the life of heating furnaces, piping, gas collectors, etc. There is a problem of shrinking.

  As a countermeasure, there is a method in which halogen is not collected as a gas but is captured during or before decomposition. Japanese Patent Application Laid-Open No. 7-188664 discloses a method in which a metal compound such as an alkali metal hydroxide is previously added to a halogen-containing synthetic resin and thermally decomposed at 250 to 700 ° C. This is because the halogen compound produced by thermal decomposition can react with the metal compound to produce a metal halide, so that the production of the halogen compound is expected to be suppressed. However, since this method is a reaction between a solid and a gas, it is estimated that there is a limit to the reactivity between the halogen-containing synthetic resin and the metal compound.

  Japanese Patent Laid-Open No. 10-219258 discloses that a halogen-containing polymer material is brought into contact with an alkaline solution to trap the halogen element contained in the polymer material in the alkaline solution, and then the polymer material is thermally decomposed. A method is disclosed. However, since the alkali solution is an aqueous solution or an alcohol solution of an alkali metal compound or an alkaline earth metal compound, when contacted with a halogen-containing polymer material, the property of dissolving or swelling the polymer material is very weak. It is considered that the alkali metal ions or alkaline earth metal ions do not penetrate into polymer materials in general.

  In JP-A-2002-80630, a halogen-containing flame-retardant resin composition is brought into contact with a mixed material composed of a dehalogenation material and a dehalogenation promoting material at a temperature lower than the thermal decomposition temperature of the resin composition. A method is disclosed. Here, the dehalogenating material is a reducing agent such as tetralin, metal, amine or sugar. In addition, there are two types of dehalogenation-promoting materials. Dehalogenation-dissolving materials that mainly dissolve alcohols and ketones and halogen-containing flame retardants as dehalogenation-promoting materials that partially decompose chemical bonds to produce resin raw materials Examples of the accelerating material include solvents such as chlorinated hydrocarbons, alcohols, ketones, and amides. This method has various improvements compared to the previous methods, but when applied to epoxy resins, which are insoluble and infusible thermosetting resins, dehalogenated materials or accelerated dehalogenation. In order for the material to penetrate into the resin, it must be processed under pressure. Under normal pressure, only the surface of the cured epoxy resin can be dehalogenated, and it is difficult to remove all the halogens.

  Japanese Patent Application Laid-Open No. 6-144801 discloses a method of recovering a bromine-containing gas produced by thermally decomposing a bromine-containing heat-resistant resin as a bromine compound by chemically reacting with an alkaline aqueous solution. Japanese Patent Laid-Open No. 9-262565 discloses that a gas produced by dry distillation of a bromine-containing flame retardant resin is completely burned to convert bromine contained in the resin into hydrogen bromide gas, which is absorbed by an aqueous sodium hydroxide solution. A method of forming a sodium bromide solution is disclosed. However, since these methods generate hydrogen bromide, there is a problem that the life of the equipment is greatly shortened due to its corrosiveness.

  Japanese Patent Application Laid-Open No. 2000-290424 discloses that a thermoplastic resin composition containing a brominated flame retardant is heated and contacted with water, alcohol, metal hydroxide, metal carbonate, octyl alcohol, and brominated flame retardant. A method for promoting the debromination of a fuel and removing bromine is disclosed. However, in this method, in a highly crosslinked thermosetting resin such as an epoxy resin, water and alcohol do not penetrate into the resin and the debromination reaction cannot be promoted.

  Japanese Patent Laid-Open No. 2001-198561 discloses bromine-containing organic decomposition product gas produced by dry distillation treatment of printed circuit board waste containing a bromine-containing resin, and after cooling and heating again, the bromine contained is brominated. A method of separating and recovering as hydrogen is disclosed. This method also generates hydrogen bromide as in the case of Japanese Patent Application Laid-Open No. 6-144801, so that there is a problem that the life of the equipment is greatly shortened due to its corrosiveness.

JP-A-2002-265392 discloses a method for dechlorinating chlorinated aryl by a simple operation under conditions of normal temperature and normal pressure without performing thermal decomposition or reflux. In this method, chlorinated aryl is subjected to dechlorination reaction by electrolysis using metal as an anode in an organic solvent in the presence of a metal salt. However, this method has a problem that it is not practical because it takes a long time for dechlorination.
JP 48-39572 A JP-A-57-174187 Japanese Patent Laid-Open No. 7-188664 JP-A-10-219258 JP 2002-80630 A Japanese Patent Laid-Open No. 6-144801 JP-A-9-262565 JP 2000-290424 A JP 2001-198561 A JP 2002-265392 A

  In view of the above, the present invention provides a highly efficient debromination method without generating corrosive hydrogen bromide.

  In order to solve this problem, the present invention enables this by electrolyzing an organic compound containing a bromine atom in an organic solvent using a metal containing zinc in at least one electrode.

That is, the present invention (1) is a method for deodorizing an organic compound containing a bromine atom, characterized by electrolyzing an organic compound containing a bromine atom in an organic solvent using a metal containing zinc for at least one electrode. It relates to a raw material method.
In the present invention (2), the organic compound containing a bromine atom is a high molecular weight product or a decomposition product thereof, The method for debromination of an organic compound containing a bromine atom according to the above (1) About.

  The present invention (3) relates to the method for debromination of an organic compound containing a bromine atom according to the above (2), wherein the high molecular weight material is a resin.

  The present invention (4) relates to the method for debromination of an organic compound containing a bromine atom according to the above (3), wherein the resin is a resin waste.

  The present invention (5) relates to the method for debromination of an organic compound containing a bromine atom according to the above (4), wherein the resin waste is a resin recovered from a printed wiring board or a material thereof. .

  The present invention (6) relates to the method for debromination of an organic compound containing a bromine atom according to the above (5), wherein the material is a laminate.

  In the present invention (7), the bromine atom-containing organic compound is an aromatic hydrocarbon containing a bromine atom, wherein the bromine atom-containing organic compound is debrominated as described in (1) above It relates to the conversion method.

  The present invention (8) relates to the method for debromination of an organic compound containing a bromine atom according to the above (1) to (7), wherein the electrolysis is performed in the presence of a supporting salt.

  The present invention (9) relates to the method for debromination of an organic compound containing a bromine atom according to the above (1) to (8), wherein the electrolysis is performed in the presence of an organic solvent and water. .

  According to the present invention, a bromine-containing gas such as corrosive hydrogen bromide is generated by electrolyzing an organic compound containing a bromine atom in an organic solvent using a metal containing zinc for at least one electrode. Therefore, highly efficient debromination is possible.

  Hereinafter, the present invention will be described in detail.

  The organic compound containing a bromine atom in the present invention may be any organic compound having a bromine atom in the molecule, and may be a low molecular weight body or a high molecular weight body. Examples of the low molecular weight substance include polybrominated diphenyl ether, polybrominated diphenyl, tetrabromobisphenol A, tetrabromobisphenol A-bis- (2,3-dibromopropyl ether), and tetrabromobisphenol A-bis (allyl ether). , Tetrabromobisphenol S, tetrabromobisphenol S-bis (2,3-dibromopropyl ether), brominated phenol novolac epoxy, brominated (alkyl) phenyl glycidyl ether, hexabromobenzene, pentabromotoluene, hexabromocyclododecane, Decabromodiphenyl oxide, octabromodiphenyl oxide, ethylene bis (pentabromophenyl), ethylene bis (tetrabromophthalimide), tetrabromophthalic anhydride, Brominated phenols such as iodinated alkylphenols, tris (tribromophenoxy) triazine, octabromotritylphenylindane, pentabromobenzyl acrylate, polydibromophenylene oxide, bis (tribromophenoxyethane), 2,4,6-tribromophenol , Alkyl bromides, and mixtures thereof. Examples of the high molecular weight material include ABS resin, polystyrene resin, polypropylene resin, polyethylene resin, polycarbonate resin, polyamide resin, polyester resin, polyurethane resin, epoxy resin, unsaturated polyester resin, phenol resin, and a mixture or decomposition product thereof. Is mentioned.

  In the present invention, the organic compound containing bromine may be a resin waste, for example, a resin recovered from the material such as a printed wiring board or a laminated board or a decomposition product thereof, a resin recovered from a casing of an electrical product, or The decomposition product may be used.

  The organic solvent in the present invention may be any as long as it dissolves an organic compound containing a bromine atom. Organic solvents such as amide, alcohol, ketone, ether, ester, and sulfoxide may be used. Can be mentioned. These may be used alone or in combination of several kinds. Examples of amide solvents include formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N, N, N ′, N'-tetramethylurea, 2-pyrrolidone, N-methyl-2-pyrrolidone, caprolactam, carbamic acid ester and the like can be mentioned.

  Examples of alcohol solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol, 1-pentanol, 2-pentanol, and 3-pentanol. 2-methyl-1-butanol, iso-pentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2- Pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, Echile Glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene Glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, polyethylene glycol (molecular weight 200-400), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butane Diol, 1,4-butanediol, 2,3- Butanediol, 1,5-pentanediol, glycerin, dipropylene glycol, benzyl alcohol and the like.

  Examples of the ketone solvents include acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phorone, isophorone, acetylacetone, Examples include acetophenone.

  Examples of the ether solvent include dipropyl ether, diisopropyl ether, dibutyl ether, dihexyl ether, anisole, phenetole, dioxane, tetrahydrofuran, acetal, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and the like. .

  Examples of the ester solvent include methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, isopentyl propionate, methyl lactate, ethyl lactate, butyl lactate , Methyl butyrate, ethyl butyrate, butyl butyrate, isopentyl butyrate, isobutyl isobutyrate, ethyl isovalerate, isopentyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, γ-butyro Tons, diethyl oxalate, dibutyl oxalate, diethyl malonate, methyl salicylate, ethylene glycol diacetate, tributyl borate, trimethyl phosphate, triethyl phosphate and the like.

  Examples of the sulfoxide solvent include dimethyl sulfoxide and diethyl sulfoxide.

  Among the above organic solvents, N, N-dimethylformamide, N-methylacetamide, N-methyl-2-pyrrolidone, methanol, diethylene glycol monomethyl are preferred because of the high solubility and stability of organic compounds containing bromine atoms. Ether, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, dimethyl sulfoxide and the like are preferable.

  The amount of the organic solvent used should be an amount that can dissolve the organic compound containing bromine atoms and can immerse the electrode, such as the type of organic compound and solvent containing bromine atoms, the size of the electrolytic cell, etc. It is appropriately selected depending on.

  In the present invention, it is preferable to add water in order to improve the efficiency of electrolysis. The amount of water used is not particularly limited as long as it can dissolve the supporting salt, and it is usually preferably 0.1 to 1 milliliter with respect to 1 mmol of the supporting salt.

  The electrolysis in the present invention is performed using a metal containing zinc for at least one of the electrodes. That is, an electrode in which only the anode is zinc, only the cathode is zinc, and both the anode and the cathode are zinc is used. In terms of efficient debromination, the anode is preferably zinc, and both the anode and the cathode are more preferably zinc. When one electrode is zinc, zinc, platinum, aluminum, iron, nickel, copper, silver, carbon, stainless steel, lead, tin, titanium, or the like can be used for the other electrode.

The current density during electrolysis, the electrode may be any value if not completely consumed ^but, 50 mA / cm 2 is preferably in the range of ~300mA / cm ^2, the range of 70mA / cm ² ~290mA / cm 2 Is more preferable. If it is less than 50 mA / cm ² , the progress of the electrolytic reaction is slow, and if it exceeds 300 mA / cm ² , the electrode is consumed very much, which is not economical.

  In the present invention, it is preferable to perform electrolysis in the presence of a supporting salt for the purpose of allowing electrolysis to proceed with high efficiency. The supporting salt is not particularly limited as long as it is sufficiently ionized in the presence of water. For example, tetraethylammonium bromide, sodium bromide, sodium chloride, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, Tetrafluoroammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, zinc bromide and the like can be used.

  The amount of the supporting salt added is preferably 0.1 to 2 mol with respect to 1 mol of bromine in the organic compound containing bromine. When the amount is less than 0.1 mol, the reaction is slow, and when the amount is more than 2 mol, electrolysis of the supporting salt may occur and current consumption also increases.

  In the present invention, electrolysis may be carried out at any temperature, but when electrolysis is carried out under normal pressure, it is preferably at least the melting point and the boiling point of the organic solvent used. More preferably, the temperature is not lower than room temperature and not higher than the boiling point of the organic solvent. If the temperature is lower than the melting point of the organic solvent, the efficiency of electrolysis decreases, and if the temperature is higher than the boiling point of the organic solvent, pressurization becomes indispensable, which is not preferable in terms of economy and safety.

  Any heating method may be used for the organic solvent, and the solvent can be directly heated with a heater, or the container containing the solvent can be indirectly heated with a heater. Further, heating may be performed using a heat medium such as oil, water, or steam.

  In addition, the atmosphere in which electrolysis is performed in the present invention may be an air or an inert gas such as nitrogen, argon, carbon dioxide, etc., and may be under normal pressure, reduced pressure, or increased pressure. When importance is attached to safety and economy, it is preferable to be under normal pressure.

The electrolysis time depends on the amount of the organic compound containing bromine, but is preferably 0.1 to 100 hours. If it is less than 0.1 hour, there is a possibility that the debromination reaction will not be completed sufficiently, and if it exceeds 100 hours, the economy is remarkably inferior. When the organic compound containing bromine is 100 mg scale, 1 to 10 hours are preferable.
During electrolysis, the inside of the electrolytic cell may be stirred to increase the reactivity. The stirring method is not particularly limited, and there are a method using a stirring blade, a method of generating a jet, a method of swinging a container, a method of using bubbles of an inert gas, and the like.

  Examples of the present invention will be described in detail below, but the present invention is not limited thereto.

Invention Example 1
In a single cell with branches, 100 mg (0.30 mmol) of 2,4,6-tribromophenol was added and dissolved by adding 5 ml of dimethylformamide, 103 mg (0.10 mmol) of sodium bromide and 0.05 ml of distilled water. It was. Two zinc electrodes (parts in contact with the solution: 1.0 cm × 2.0 cm, distance between electrodes: 8 mm) were attached and energized while stirring at 40 ° C. and a terminal voltage of 10V. One hour after the start of energization, 0.5 μl was sampled, and the yield of phenol was determined by high performance liquid chromatography. Further, the debromination rate is defined as phenol yield / (2,4,6-tribromophenol recovery rate + dibromophenol yield + monobromophenol yield + phenol yield) × 100 (%) Determined by The results are shown in Table 1.

Invention Examples 2 to 11
Using a predetermined solvent and a supporting salt shown in Table 1, an electrolytic reaction was carried out in accordance with Example 1 of the present invention under predetermined conditions, and a phenol yield and a debromination rate were determined. The results are shown in Table 1.

Invention Example 12
Tetrabromobisphenol A was used in place of 2,4,6-tribromophenol, and an electrolytic reaction was carried out according to the present invention example 1 under the predetermined conditions shown in Table 1 to determine the yield of bisphenol A. Further, the debromination rate (%) is defined as the yield of bisphenol A / (the recovery rate of tetrabromobisphenol A + the yield of tribromobisphenol A + the yield of dibromobisphenol A + the yield of monobromobisphenol A + the bisphenol A). Yield) × 100 (%). The results are shown in Table 1.

Comparative Examples 1-4
Using predetermined electrolytes, solvents, and supporting salts shown in Table 1, an electrolytic reaction was performed in accordance with Example 1 of the present invention under predetermined conditions, and phenol yield and debromination rate were determined. The results are shown in Table 1.

Invention Examples 13-15
The resin decomposition product obtained from the brominated epoxy resin copper clad laminate MCL-E-67 commercially available from Hitachi Chemical Co., Ltd. was electrolyzed. The laminate used was composed of a cured brominated epoxy resin, glass cloth, and copper foil. This laminate was dissolved at normal pressure with a treatment solution consisting of tripotassium phosphate and N-methylpyrrolidone as an alkali metal compound. Then, the solvent was removed to obtain a resin decomposition product. As a result of examining the bromine content of this resin decomposition product by the oxygen flask combustion method, it was 17.5%.

  Using 100 mg of this resin decomposition product, an electrolytic reaction was carried out in accordance with Example 1 of the present invention under predetermined conditions using the predetermined solvent and supporting salt shown in Table 2. After electrolysis, the reaction solution was distilled under reduced pressure to remove the solvent, and the resulting powder was washed with water to remove the supporting salt, and then dried to measure the bromine content. The results are shown in Table 2.

Invention Example 16
Except for changing to a commercially available brominated epoxy resin (ESB-400T manufactured by Sumitomo Chemical Co., Ltd.) (bromine content: 48%) (100 mg), electrolysis was performed according to Example 1 of the present invention, and bromine contained The rate was examined. The results are shown in Table 2.

Comparative Examples 5-6
Using predetermined electrolytes, solvents, and supporting salts shown in Table 3, an electrolytic reaction was performed in accordance with Example 1 of the present invention under predetermined conditions, and phenol yield and dechlorination rate were determined. The results are shown in Table 3. Dechlorination rate (%) is obtained by the following formula: phenol yield / (2,4,6-trichlorophenol recovery rate + dichlorophenol yield + monochlorophenol yield + phenol yield) × 100 (%) It was.

From Tables 1 to 3, Invention Examples 1 to 16 obtained by electrolyzing an organic compound containing a bromine atom in an organic solvent using a zinc electrode have a high debromination rate and a high yield of debrominated product. You can see that On the other hand, in Comparative Examples 1 to 4 using no zinc electrode, the debromination reaction did not proceed, and a debrominated product could not be obtained. Moreover, in Comparative Examples 5-6 using a chlorine containing organic compound, even if it used the zinc electrode, dechlorination reaction did not advance and the dechlorination thing was not able to be obtained.

Claims (9)

  A method for debromination of an organic compound containing a bromine atom, comprising electrolyzing an organic compound containing a bromine atom in an organic solvent using a metal containing zinc in at least one electrode.   The method for debromination of an organic compound containing a bromine atom according to claim 1, wherein the organic compound containing a bromine atom is a high molecular weight product or a decomposition product thereof.   The method for debromination of an organic compound containing a bromine atom according to claim 2, wherein the high molecular weight substance is a resin.   The said resin is resin waste, The debromination method of the organic compound containing a bromine atom of Claim 3 characterized by the above-mentioned.   The method for debromination of an organic compound containing bromine atoms according to claim 4, wherein the resin waste is a resin recovered from a printed wiring board or a material thereof.   6. The method for debromination of an organic compound containing a bromine atom according to claim 5, wherein the material is a laminate.   2. The method for debromination of an organic compound containing a bromine atom according to claim 1, wherein the organic compound containing a bromine atom is an aromatic hydrocarbon containing a bromine atom.   The method for debromination of an organic compound containing a bromine atom according to claim 1, wherein the electrolysis is performed in the presence of a supporting salt.   The method for debromination of an organic compound containing a bromine atom according to claim 1, wherein the electrolysis is performed in the presence of an organic solvent and water.