JPH0260668A - Method for decomposing halogenated acyclic hydrocarbon compounds - Google Patents

Abstract

PURPOSE:To continuously decompose the acyclic hydrocarbon halide compd. at a high decomposition ratio by causing silent discharge in a gaseous mixture composed of the gas of the acyclic hydrocarbon halide compd. and a gas contg. at least oxygen. CONSTITUTION:A copper wire coil electrode 2 wound with a copper wire is provided to the outer periphery of a glass reaction vessel 1 and a stainless steel electrode 3 is inserted into the hollow part of the glass reaction vessel. Air (100l/hrs) contg., for example, 100ppm dichlorodifluoromethane is introduced form an introducing port 4 into the vessel 1 and the decomposition by the silent discharge is executed. The 1ppm dichlorodifluoromethane, carbon monoxide, carbon dioxide, hydrochloric acid, hydrofluoric acid, etc., are detected if the gaseous components discharged from a discharge port 5 are analyzed by gas chromatogram. The efficient decomposition is possible if such reaction devices are installed in many stages or the residence time of the gases in the reaction devices is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the decomposition of halogenated acyclic hydrocarbon compounds, particularly fluorinated hydrocarbons, chlorinated hydrocarbons, or mixed fluorinated and chlorinated acyclic hydrocarbon compounds. Regarding the method.

BACKGROUND OF THE INVENTION Halogenated acyclic hydrocarbon compounds are generally very stable substances and will not spontaneously decompose unless they are specially treated. When these substances are released into the atmosphere, they diffuse into the stratosphere and are first broken down in the ozone layer within the stratosphere.

During this decomposition, ozone in the stratosphere is consumed, and short-wavelength ultraviolet rays contained in sunlight that are absorbed by ozone fall directly onto the earth's surface. As a result, there are concerns that short-wavelength ultraviolet rays, which are harmful to living things, may damage cells and genes and have a major impact on biological systems.

A method for easily decomposing these halogenated hydrocarbon compounds is strongly desired, and measures are being taken to significantly reduce the amount emitted into the atmosphere.

Conventionally, as a method of decomposing this kind of stable halogenated acyclic hydrocarbon compound, there is a method of burning it at a high temperature of 1200 degrees or more. This method requires a furnace that can withstand high temperatures and hydrogen halides, such as hydrogen chloride and hydrogen fluoride, generated by combustion, so it requires large-scale equipment and is expensive. As a method for solving these drawbacks, a method has been proposed in which a halogenated aromatic compound is heated in the coexistence of hydroxide (for example, Japanese Patent Publication No. 37831/1983).

Problems to be Solved by the Invention In such conventional methods, when applied to halogenated acyclic hydrocarbon compounds having a relatively low boiling point, the decomposition rate is low;
Furthermore, it has the disadvantage of requiring batch processing. Furthermore, in a low-temperature recovery method, there is a need for a method for inexpensively, easily, and harmlessly decomposing trace amounts of halogenated acyclic hydrocarbons that are leaked from recovery equipment.

The present invention was made to improve these points.
The present invention provides a method for continuously decomposing halogenated acyclic hydrocarbon compounds at a high decomposition rate.

Means for Solving the Problems In order to solve the above problems, the halogenated acyclic hydrocarbon compound is decomposed by silently discharging it in a mixed gas of the halogenated acyclic hydrocarbon compound gas and a gas containing at least oxygen. It is something.

According to the present invention, a halogenated acyclic hydrocarbon compound is oxidatively decomposed by silently discharging it in a mixed gas of a gas of the halogenated acyclic hydrocarbon compound and a gas containing at least oxygen. Therefore, it has a high decomposition rate and is less harmful.
It becomes possible to decompose it into compounds or compounds that can be easily recovered.

Example Embodiments of the present invention will be described below with reference to the drawings.

The drawing is a schematic representation of the apparatus used to demonstrate the method of the invention. In the figure, 1 is a glass reaction vessel, 2 is a copper wire coil electrode wrapped around the outer periphery of the glass reaction vessel, 3 is a stainless steel electrode placed in the hollow part of the glass reaction vessel,
Reference numeral 4 indicates an inlet for introducing a mixture of a gas of a halogenated acyclic hydrocarbon compound and a gas containing at least oxygen, and 5 indicates an outlet for cracked gas. During disassembly, 15kV between 3.2
Apply a voltage of

(Example 1) Using the above-mentioned apparatus, air containing 1100 PP dichlorodifluoromethane (100 R/hrs) was introduced into the glass reaction vessel 1 from the inlet 4, and decomposition was performed by silent discharge. As a result of gas chromatogram analysis of the gas components discharged from the outlet 5, IPPM dichlorodifluoromethane, carbon oxide, carbon dioxide, hydrochloric acid, hydrofluoric acid, and the like were detected. Efficient decomposition can be achieved by installing such reactors in multiple stages or by controlling the residence time of the gas within the reactor.

(Example 2) Dichlorodifluoromethane was supplied under the same conditions as in Example 1, and the gas discharged from the outlet was introduced into a gas absorption bottle filled with water to recover hydrogen chloride and hydrogen fluoride. . Analysis of the gas discharged from the gas absorption bottle revealed that the concentration of dichlorodifluoromethane was 0.9 PPM.

(Example 3) Air containing 500 PPM of Freon 113 (100 R/h
rs) was introduced into the glass reaction vessel 1 through the gas inlet 4 and decomposed by silent discharge.

The Freon 113 discharged from the discharge port 5 was 5 PPM.

The reason why the stable halogenated acyclic hydrocarbon compound is decomposed in this way is presumed to be that the silent discharge causes a dehalogenation reaction and a carbon-carbon bond cleavage reaction.

In the examples, dichlorodifluoromethane and Freon 11
Although 3 was explained, it is obvious that other halogenated acyclic hydrocarbon compounds are also effective. It is also possible to increase the decomposition rate by using multiple reaction vessels. Furthermore, in the explanation of the examples, glass was used as the reaction/container, but a material that is corrosion resistant to hydrogen fluoride, which is a decomposing acid organism, may be used, or the inside of the container may be coated with such a material. . In addition, although the wet method was explained as the recovery device, it is obvious that the same effect can be obtained in the dry method.

Effects of the Invention As described above, according to the present invention, it is possible to decompose halogenated acyclic hydrocarbon compounds with high efficiency. Therefore, it will be possible to treat the above-mentioned compounds contained in exhaust gas at electronics industry factories that use halogenated acyclic hydrocarbon compounds in the cleaning process, and this will put a brake on the destruction of the ossine layer in the stratosphere. It is extremely useful for industry as it makes it possible to

[Brief explanation of the drawing]

The figure is a schematic diagram of a decomposition apparatus embodying a method for decomposing a halogenated acyclic hydrocarbon compound according to an embodiment of the present invention. 1... Glass reaction vessel, 2... Copper wire coil electrode, 3
...Stainless steel electrode, 4.Inlet, 5.Outlet. Name of agent: Patent attorney Shigetaka Awano 1 person = 437? , aI7 soot Koio goose

Claims (1)

[Claims] 1. A method for decomposing a halogenated acyclic hydrocarbon compound, which comprises silently discharging a mixture of a gas of the halogenated acyclic hydrocarbon compound and a gas containing at least oxygen.