JPS594442A - Treatment of carbonaceous material - Google Patents

Abstract

PURPOSE:To suppress an amt. of byproduct greatly in hydrogen chloride removing reaction, by treating carbonaceous materials with a radical capturing agent, such as phenols. CONSTITUTION:When carbonaceous materials produced by carbonizing carbon black, polyvinyl chloride, formaldehyde resin, etc. are used as catalyst carriers, they are immersed into a soln. of a phenolic radical capturing agent, such as hydroquinone, catechol, trimethylhydroquinone, p-t-butylcatechol, naphthol, pyrogallol, and heated to 50-150 deg.C with stirring, then washed with a solvent, and dried.

Description

[Detailed description of the invention] It relates to a method of processing materials.

Activated carbon is generally produced from plant-based materials such as wood and coconut shells, or from mineral-based materials such as coal, petroleum residue, and petroleum coke. Activated carbon is fine quality carbon whose basic component is microcrystals, and is a porous carbon body with developed pores. Therefore, it has a high adsorption capacity and is used in various industrial fields for gas purification, solvent recovery, water purification, etc. Furthermore, the specific surface area is 50
0 to 15 [10yy! /9 as big as 500
~60.

It is heat resistant up to °C and has extremely high heat resistance and alkali resistance, so it is often used as a catalyst or catalyst carrier.

Carbon black is an amorphous carbon material containing graphite crystallites produced by pyrolysis or controlled explosion of hydrocarbon liquids or gases. pigment.

Filling agent. It is used as a reinforcing agent, but because it has a large surface area, it can be used as a catalyst.

Carbon materials produced by carbonization of synthetic polymers include vinyl chloride charcoal, 3,5-dimethylphenol formaldehyde resin charcoal, polyvinylidene chloride resin charcoal, acetone furfural resin charcoal, phenol formaldehyde resin charcoal,
Obtained by heating and carbonizing polyacrylonitrile or in an inert gas.

A feature of carbon materials that is not found in ordinary catalysts or catalyst carriers is that they have unpaired electrons. The concentration of unpaired electrons in a carbon material is related to the carbonization temperature in the carbonization process, and for example, in activated carbon, it is usually measured at 1g1l to 10!0 electrons/f (edited by Kusa Ozaki et al.).

“Catalyst Engineering Course Volume 10” p. 128, Chidai Shokan).

Various carbon materials including activated carbon are used as catalysts or catalyst carriers. Examples include halogen addition reactions to olefins, substitution halogenation reactions, dehydrohalogenation reactions of organic halides, and dehydrogenation reactions of hydrocarbons (Carbon Materials Society Network, ``Activated Carbon Basics and Applications'', Kokisha, p. 321). , 1975).

Among these, an example of a reaction that is of industrial interest is 1.
There is the production of vinyl chloride by catalytic dehydrochlorination of 2-dichloroethane. It is known that activated carbon having a large specific surface area is a good catalyst for this reaction as well.

However, 1, which also has industrial significance 1, 1.2-)
It has been found that conventionally known carbon materials are not good catalysts for the synthesis of vinylidene chloride by catalytic dehydrochlorination of IJ dichloroethane, the synthesis of chloroprene by catalytic dehydrochlorination of he-4-dichloro-1-butene, etc. That is, when the catalytic dehydrochlorination reaction of 1.1.2-) dichloroethane was carried out using activated carbon as a catalyst or catalyst carrier, many byproducts such as vinyl chloride, cis- and trans-1,2-dichloroethylene were produced. However, the selectivity to the target vinylidene chloride was extremely low. In addition, in the case of he-4-dichloro-1-butene, the target product chloroprene is rarely obtained, and 1,4-dichloro-2
By-products such as -butene and 1-chlorobutadiene are obtained. The use of polyacrylonitrile carbon as a catalyst for the catalytic dehydrochlorination reaction of 1.1.2-trichloroethane has been reported, but the selectivity to vinylidene chloride is not very high.

The present inventors noticed that vinylidene chloride and chloroprene are produced from 1.1.2-) dichloroethane or 5.4-dichloro-1-butene, respectively, by ionic or concerted dehydrochlorination reactions. We also investigated ways to treat carbon materials for use as catalysts or catalyst carriers.

As a result, carbon materials treated with compounds that normally exhibit radical scavenging properties, such as hydroquinone or paratertiary butylcatechol, such as activated carbon as a total catalyst or catalyst support, can be used to convert 1,1,2-trichloroethane or The present invention was achieved by discovering that the amount of by-products in the dehydrochlorination reaction of 4-dichloro-1-butene can be greatly suppressed.

The cause of the treatment effect of the carbon material of the present invention is considered as follows. In other words, the reason why untreated carbon materials do not give good results as a dehydrochlorination catalyst is because the unpaired electrons contained in the catalyst promote side reactions. It is thought that the unpaired electrons included were removed and side reactions were suppressed. Therefore, this treatment method can be widely applied to the treatment of carbon materials as catalysts or catalyst carriers for reactions in which participation of radicals is undesirable.

That is, the present invention provides a complete method for treating a carbon material, which is characterized in that the carbon material is treated with a radical scavenger when the material is used as a catalyst or a catalyst carrier.

Below, the present invention'l! - Explain in more detail.

The present invention is a treatment method for using a carbon material as a catalyst or catalyst carrier.

Carbon materials commonly used as catalysts or catalyst supports include, for example, activated carbon, carbon black or polyvinyl chloride, which are vegetable or mineral based carbon raw materials.
-Dimethylphenol, formaldehyde resin, polyvinylidene chloride resin.

Examples include carbon materials produced by carbonization of synthetic polymers such as acetone furfural resin, phenol formaldehyde resin, and polyacrylonitrile. Preferably,
It is an activated carbon with a large specific surface area. As the activated carbon to be treated, it is possible to use commonly used activated carbons made from plant-based raw materials such as wood and coconut shells, or those made from mineral-based raw materials such as coal, petroleum residue, and petroleum coke. The activation method applied to the activated carbon may be a conventional method, such as a steam activation method or a zinc chloride method.

The radical scavenger used in the present invention is an organic compound or inorganic compound that exhibits a radical scavenging action, such as hydroquinone, catechol, trimethylhydroquinone, and paratertiary butylcatechol.

Phenols such as naphthol and pyrogallol, or heterocyclic compounds containing any of nitrogen, oxygen and sulfur such as phenothiazine, inorganic compounds such as iron trichloride may be used, but phenols are preferred, especially hydroquinone or fC. Haparatertiary butylcatechol is preferred.

A simple method for treating the carbon material is to immerse the carbon material in a solution of a radical scavenger. For example, activated carbon is placed in a hydroquinone or paratertiary butyl catechol solution, immersed in the solution while heating and stirring, and then washed and dried. At that time, the heating temperature may vary depending on the solvent used, but is usually in the range of 50 to 150°C. The heating time varies depending on the amount of activated carbon to be treated and the concentration of the radical scavenger solution, but 30 minutes or more is sufficient. The concentration of the radical scavenger solution can be selected within a wide range, but any concentration of 0.05M or higher is acceptable. Any solvent may be used as long as it dissolves the radical scavenger, and usually ethanol or water can be used. The immersed activated carbon is sent to each house and washed with a solvent.

There are no particular restrictions on the drying method, but it is sufficient to remove the solvent under normal pressure or reduced pressure, for example, by heating at 200°C or less, or by heating at 200°C or less. element, hydrogen, argon, helium.

This may be carried out in the presence of an inert gas such as carbon dioxide.

The carbon material treated as described above can be used as a catalyst as it is, but it can also be used as a carrier for supporting catalyst components.

The catalyst or catalyst carrier of the present invention is effective in the various reactions mentioned above, but the most remarkable effect is dehalogenation of halogenated hydrocarbons having 1 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and more preferably 2 to 4 carbon atoms. Expressed in hydrogen reactions.

For example, a catalyst in which a 1 to 1 complex of cesium chloride and dibenzo-24-crown-8 or a 1:2 complex of cesium chloride and dibenzo-18-crown-6 is supported on activated carbon treated by the method of the present invention is used. When a catalytic membrane hydrogen chloride reaction of 1,1,2-trichloroethane or he4-dichloro-1-butene was carried out, the selectivity to vinylidene chloride or chloroprene was significantly higher than that of a catalyst in which the above complex was supported on untreated activated carbon. The kernels obtained are a major feature of the present invention.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Commercially available 4 to 6 mesh monomineral granular activated carbon 202 gold was added to 100 + + + t of an ethanol bath solution of paratertiary butylcatechol at a concentration of α5 mol←), and the mixture was heated under reflux for 10 hours. After the activated carbon was separated by purification, it was washed with 300 g of ethanol. It was further dried under reduced pressure.

The activated carbon treated in this way is mixed with cesium chloride and dibenzo.
The complex was placed in a methanol solution of 24-crown-8 at a molar ratio of 1:1 and heated with stirring. Cesium-dibenzo-2 is added to activated carbon by distilling off the solvent and drying it.
A catalyst containing 20 4-crown-8 complexes by weight was obtained.

The catalyst thus prepared had an inner diameter of 20+nmφ.

The mixture was filled into a 600 m long blind Pyrex reaction tube and heated to 250° C. in a tubular electric furnace. 1 o capacity steam train 1
．． 1.2- Nitrogen gas containing trichloroethane 2
50 m was continuously fed to the reaction tube in 21 minutes. The reaction product gas was quantified by gas chromatography, and the selectivity of each product was calculated.

The reaction results are shown in Table 1.

Example 2 The same granular activated carbon as in Example 1 was added to an ethanol solution of paratertiary lipylcatechol at a concentration (112M) of 20%
2 was added and heated under reflux for 5 hours. After filtration and separation through activated carbon, the mixture was further heated under reflux for 1 hour in 600% ethanol. After filtering and washing the activated carbon, it was dried under reduced pressure.

The activated carbon treated in this manner was charged into a reaction tube in the same manner as in Example 1, and 1,1.2-1-lichloroethane was continuously supplied. The reaction conditions were the same as in Example 1.

The complete reaction results are shown in Table 1.

Example 5 102 pieces of the same activated carbon as in Example 1 were added to 100 g of hydroquinone water bath solution having a concentration of 1118 M, and heated while stirring on a water bath (70 to 80°C) for 4 hours. Filter and separate activated carbon 3
After washing with 00 ml of water, it was dried under reduced pressure.

The activated carbon thus treated was charged into a reaction tube in the same manner as in Example 1, and 1.1.2-)lichloroethane was continuously supplied. The reaction conditions were the same as in Example 1.

The reaction results are shown in Table 1.

Example 4 102 pieces of commercially available coconut shell activated carbon of 10 to 32 mesohydroles were added to an ethanol solution of hydroquinone having a concentration of 0.2M, and the mixture was heated under reflux for 5 hours. After separation by filtration with activated carbon, the mixture was heated under reflux for 1 hour in an ethanol bath medium. After filtering and washing with activated carbon, it was dried under reduced pressure.

The activated carbon thus treated was heated in a methanol solution containing a complex of cesium and dibenzo-18-crown-6 in a molar ratio of 1:2. The solvent was distilled off and the mixture was dried to obtain a catalyst in which 15% by weight of Senram-dipenzo-18-crown-6 complex was supported on activated carbon. The reaction tube was filled in the same manner as in Example 1 with this catalyst, and the dehydrochlorination reaction of 1.1.2-)lichloroethane was carried out.

The results of the reaction are shown in Table 1.

Example 5 The same activated carbon as in Example 4 was added to a concentrated 0.3 M ethanol solution of paratertiary butylcatechol. This catalyst was charged into a reaction tube in the same manner as in Example 1, and Let it react next. The results of the reaction are shown in Table 1.

Comparative Example 4 The same untreated coconut shell activated carbon as in Example 4 was filled into a reaction tube in the same manner as in Example 1, and a 1,1.2-1 reaction was carried out. Result of reaction? It is shown in Table 1.

Comparative Example 5 A catalyst was prepared in which cesium-dibenzo-24-1-80 molar ratio 1:1 was supported on the same untreated granular activated carbon as in Example 1.

This catalyst was charged into a reaction tube in the same manner as in Example 1, and 4-dichloro-1-7'tene was continuously fed to react. The results of the reaction are shown in Table 3.

Table 6 Patent applicant: Toyo Soda Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] (1) A method for treating a carbon material, which comprises treating the carbon material with a radical scavenger when the carbon material is used as a catalyst or a catalyst carrier. Q) The treatment method according to claim (1), wherein the radical scavenger is a phenol. (3) Claim No. (1) in which the carbon material is activated carbon
Treatment method described in section.