JP2737308B2 - Method for producing partially chlorinated methane - Google Patents

Description

The present invention relates to a method for producing partially chlorinated methane, chloroform, methylene chloride, and methyl chloride.

[Problems to be solved by the prior art and the invention] As a method for producing chloroform, methylene chloride, and methyl chloride, conventionally, methane is mixed with chlorine at a high temperature of 400 to 500 ° C or under light irradiation of a wavelength of 3000 to 5000 ° C. A reaction method is known. Further, there is known a so-called methanol method in which methyl chloride is produced by reacting with hydrochloric acid using methanol as a starting material, and then chlorinated to produce higher chlorinated methane.

However, the composition ratio of the chlorinated methane produced in any of the methods can be changed by adjusting the reaction conditions, but it is not possible to produce only a single compound, and a mixture of a plurality of chlorinated methanes must be produced. Is obtained. If you want to obtain higher chlorinated methane, you can achieve its purpose by recycling the product, but partially chlorinated completely chlorinated carbon tetrachloride Conversion to methane (chloroform, methylene chloride, methyl chloride) is not possible with conventional chlorination processes. As a method of partially reducing carbon tetrachloride, there are known a method of reducing hydrogen with nascent hydrogen generated by reacting hydrochloric acid with iron and a method of heating to a high temperature in the presence of a lower alkane such as methane or ethane. . However, the former consumes a large amount of iron and must treat a large amount of by-produced iron chloride, and cannot be adopted on an industrial scale in terms of cost. It has problems such as accompanying.

Means for Solving the Problems The present invention has been made to solve the problems of the prior art as described above, and completely chlorinated carbon tetrachloride is converted into partially chlorinated methane (methane). It is an object of the present invention to provide a novel production method for conversion to chloroform / methylene chloride / methyl chloride).

That is, the present invention relates to a method for producing partially chlorinated methane, which comprises reacting carbon tetrachloride with hydrogen in the presence of an iron group element or platinum group element catalyst to obtain partially chlorinated methane.

As the iron group element catalyst in the present invention, Fe, Co, Ni,
Examples of the platinum group element catalyst include Pd, Pt, Ru, Rh and the like. These iron group element or platinum group element catalysts may be used in combination of two or more kinds, and can be supported on a carrier such as activated carbon, diatomaceous earth or alumina, thereby increasing the catalyst activity and extending the catalyst life. Can be. In the present reaction, a platinum group element catalyst having high acid resistance is preferable because hydrogen chloride is by-produced.

When the reaction temperature in the present invention is too low, a sufficient conversion cannot be obtained, and when it is too high, a high boiling point component is generated due to a side reaction although the reaction rate is high, and the selectivity is lowered or the catalyst is reduced. 100 to 4
The temperature may be selected from the range of 00 ° C, preferably 150 to 350 ° C. The reaction can be performed in a liquid phase or a gas phase at normal pressure or under pressure, but a gas phase method is preferred from the viewpoint of selectivity and catalyst life. The reaction time in the gas phase is approximately 5 to 600 seconds, preferably 10
~ 100 seconds is appropriate.

If the amount of hydrogen used is less than 1 mole of the carbon tetrachloride used, the reaction rate of carbon tetrachloride cannot be made 100%, and if it is too large, the amount of unnecessary methane generated is reduced. The result is more. Therefore, the amount of hydrogen to be used may be an optimal amount depending on whether the most desired product is chloroform, methylene chloride, or methyl chloride. It is preferable that

[Example] Example 1 0.5 wt% of activated carbon in an iron reactor having a diameter of 1 inch and a length of 1 m
Was charged to 250 ° C. using a mantle heater. 154 g (1 mol) / hr of vaporized carbon tetrachloride was supplied to the reactor together with 34 N / hr of hydrogen. The molar ratio of carbon tetrachloride to hydrogen is 1: 1.5.
The gas from the reactor outlet was valved in a 5% NaOH abatement bottle to give an oily product at the bottom and uncondensed gas came out of the abatement bottle. By sampling for 30 minutes, 45 g of an oily product and a non-condensed gas 14 were obtained. According to gas chromatography analysis, the composition of the oily product was corrected to 15% carbon tetrachloride, chloroform
68%, methylene chloride 14%, and methyl chloride 3%.

On the other hand, the composition of the non-condensed gas is chloroform 8%,
Methylene chloride was 23%, methyl chloride was 54%, and methane was 15%. However, hydrogen was not detected under the analysis conditions of the gas chromatography, so that it was not counted in the composition.

Example 2 The reactor used in Example 1 was heated to 200 ° C., and 70 g (0.45 mol) / hr of carbon tetrachloride and 25 Nl / hr of hydrogen were supplied thereto. The molar ratio of carbon tetrachloride to hydrogen is 1: 2.5. Sampling for 30 minutes as in Example 1 yielded 26 g of an oily product at the bottom of the abatement bottle. According to the same gas chromatography analysis as in Example 1, the composition of the oily product was 38% of carbon tetrachloride, 43% of chloroform, 18% of methylene chloride, and 2% of methyl chloride. In addition, the gas discharged from the bottle was almost hydrogen and could not be captured.

Example 3 The reactor used in Example 1 was charged with a catalyst in which 2% by weight of platinum was supported on activated carbon, and this was charged with a mantle heater.
Heated to 0 ° C. Carbon tetrachloride 154 vaporized in this reactor
g (1 mol) hr were fed together with 34 Nl / hr of hydrogen. The molar ratio of carbon tetrachloride to hydrogen is 1: 1.5. By valved in a 5% NaOH abatement bottle from the reactor outlet, an oily product was obtained at the bottom and uncondensed gas came out of the abatement bottle. Oily product 52 after 30 minutes of sampling
The non-condensed gas obtained in g contained almost no hydrogen and could not be analyzed. According to gas chromatography analysis, the composition of the oily product was 38% of carbon tetrachloride, 48% of chloroform, 12% of methylene chloride, and 2% of methyl chloride.

[Effects of the Invention] The present invention can effectively convert carbon tetrachloride into chloroform, methylene chloride, and methyl chloride as shown in Examples. According to the present invention, methane or carbon tetrachloride obtained by a chlorination reaction can be partially reduced, and any partially chlorinated methane can be obtained by using it together with a conventional method for producing carbon tetrachloride by a chlorination reaction. Can be efficiently produced from methane or methanol.

Claims (4)

(57) [Claims] (1) In the presence of an iron group element or platinum group element catalyst,
A method for producing partially chlorinated methane, comprising reacting carbon tetrachloride with hydrogen to obtain partially chlorinated methane. 2. The method according to claim 1, wherein the iron group element or platinum group element catalyst is supported on activated carbon, diatomaceous earth or alumina. 3. The method according to claim 1, wherein the reaction temperature is selected from the range of 150 ° C. to 350 ° C. 4. The production method according to claim 1, wherein hydrogen is used in an amount of 1 to 3 times mol of carbon tetrachloride.