JPS6366257B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an oxyhalogenation catalyst, particularly an oxyhalogenation catalyst suitable for use in the oxychlorination reaction of ethylene. Conventionally, oxyhalogenation reaction catalysts have copper chloride, iron chloride, silver chloride, lead chloride, platinum chloride, gold chloride, ruthenium chloride, chromium chloride, etc. as main components, and supplementary components such as potassium chloride, sodium chloride,
A suitable combination of chlorides such as magnesium chloride and cesium chloride, supported on a carrier, is generally used. In this case, the carrier is
Alumina, silica gel, silica-alumina, activated carbon, acid clay, pumice, etc. are known, but alumina, silica, or these have characteristics such as large specific surface area, heat resistance, and high mechanical strength. The main components are put into practical use. For example, catalysts with copper chloride supported on alumina or silica have been used in the production of 1,2-dichlorothane by the oxychlorination of ethylene; The problem to be solved is that the selectivity of 1,2-dichloroethane is reduced due to the production of gas, ethyl chloride, chloral, and 1,1,2-trichloroethane. As a result of various studies to develop a catalyst that suppresses side reactions, the present inventors found that the acid strength of the support and the side reactions are the primary
It was found that there is a correlation as shown in the figure. That is, FIG. 1 shows the relationship between the acid strength function Ho of the alumina support and the selectivity (%) of carbon monoxide and carbon dioxide gas by combustion reaction, based on the examples described later. In the examples, the acid strength function Ho was expressed in a fixed range because it was based on color observation of the indicator, but in FIG. 1, the midpoint of the range was calculated and plotted. As is clear from Figure 1, there is a phenomenon in which the combustion reaction is suppressed as the acid strength function Ho increases, but when the acid strength function Ho is around 7, it is suppressed to about half that of the conventional product (using untreated alumina). , especially when the number is 12 or more, it is significantly suppressed. The present invention was made based on the above phenomenon, and is characterized by the use of a basic carrier as the carrier. That is, the present invention provides an oxyhalogenation catalyst supported on a basic carrier. Specifically, the present invention provides an oxyhalogenation catalyst in which cupric chloride is supported on a basic carrier having a Hammett's acid strength function Ho of 6.8 or more. The carrier used in the present invention is a catalyst carrier conventionally used in oxyhalogenation reactions, that is, a catalyst in which the catalyst is dispersed,
There is no difference in the original function of increasing the surface area and increasing the reaction activity per unit weight of catalyst. However, it significantly prevents side reactions, especially combustion reactions, which would otherwise occur due to the acidity of conventionally used carriers. Therefore, in the present invention, conventional carrier compounds can be used, and those skilled in the art can easily select and employ them based on the description in this specification. In the present invention, basicity means that the acid strength function Ho of the Hammett exhibits a basic color when the indicator is neutral red (For the acid strength function of the Hammett, refer to "Catalyst Experiment Manual" 246). ~248 pages, edited by the Catalysis Society, published in 1971, published by Maki Shoten). The carrier used in the present invention may itself be basic, but alumina, silica, or an acidic carrier mainly composed of alumina, silica, or the like, which has a large specific surface area, heat resistance, and high mechanical strength, may be used as a basic carrier as described below. Those made basic with a basifying agent are preferably used. Especially for alumina, the specific surface area is
Activated alumina with an area of 150 to 300 m ² /g is used, and silica gel with a specific surface area of 150 to 400 m ² /g is preferably used as silica. In the present invention, the method for making the acidic carrier basic is not particularly limited. The basifying agent used is an alkali metal or alkaline earth metal hydroxide, oxide, carbonate, etc., and the acidic carrier is made basic or an oxyhalogenated catalyst is supported in advance. It is common to make acidic carriers basic. Hydroxides of alkali metals or alkaline earth metals include sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, etc.; oxides include sodium oxide, potassium oxide, lithium oxide, Calcium oxide, etc., and carbonates such as sodium carbonate,
Examples include potassium carbonate, and among these, alkali metal hydroxides are particularly preferably used. These basifying agents are generally used in aqueous solution. The basification method is not particularly limited, and a method of basifying the acidic carrier or an acidic carrier on which an oxyhalogenation catalyst has been previously supported is immersed in an aqueous solution of a basifying agent is particularly preferably employed because it is simple. Ru. As a method for supporting the oxyhalogenation catalyst on the acidic carrier in advance, a known method such as a dipping method, a coprecipitation method, a post-precipitation method, etc. can be employed. The degree of basification of the acidic carrier is preferably set to Hammet's acid strength function Ho = 6.8 or more, preferably 12 or more, and can be controlled by changing the type or concentration of the basification agent or the number of immersion times. It will be done. The acid sites of the carrier thus made basic are neutralized, and the carrier is further impregnated with the basifying agent. The amount of impregnation is generally 2% by weight or more, preferably 9% by weight or more in terms of hydroxide. The basic methods for producing the oxyhalogenation catalyst of the present invention can be broadly classified into the following two methods, but it is natural that they can be modified as appropriate. (1) An acidic carrier is impregnated with an aqueous solution of a basifying agent by a method such as dipping and dried to obtain a basic carrier. Next, an aqueous solution of the oxyhalogenation catalyst is supported on this basic carrier by a method such as dipping, and then dried to obtain the oxyhalogenation catalyst of the present invention. (2) Contrary to the method in (1), first, the oxyhalogenation catalyst is supported on an acidic carrier by a dipping method, coprecipitation method, etc., and then dried. Next, this is impregnated with an aqueous solution of a basicizing agent by a method such as dipping, and dried to obtain the oxyhalogenation catalyst of the present invention. If the oxyhalogenation catalyst obtained by the above method is calcined at a higher temperature, the basicity will decrease slightly, but a strong bond can be formed. However, alkaline earth metal hydroxides, oxides,
In a basic carrier obtained using a carbonate or the like, new acid sites are generated by high-temperature calcination, so high-temperature calcination is not preferred in this case. The oxyhalogenation catalyst of the present invention is characterized in that side reactions, particularly combustion reactions, are significantly suppressed.
Therefore, 1,2-dichloroethane is produced by oxychlorination of ethylene, trichlorethylene and perchlorethylene are produced by oxychlorination of 1,2-dichloroethane, methylene chloride and tetrachloride are produced by oxychlorination of methane. It is preferably used in the production of carbon and chloroform. Examples will be described below, but the present invention is not limited thereto. To measure the acid strength function Ho, place approximately 0.1 g of the sample in a test tube, add 3 to 5 ml of benzene, and then add a small amount of benzene solution containing 0.1% of the various PKa indicators shown in Table 1. I went and observed the colors.

[Table] Example 1 The average particle size is 55 μm, and the acid strength function Ho of the hook is −
γ-alumina of 3.0 to +4.8 (specific surface area 203m ² /g)
immersed in 6% sodium hydroxide aqueous solution for 3 hours,
It was then dried at 120°C. The amount of sodium hydroxide impregnated into the γ-alumina support was 9% by weight, and the acid strength function
Ho was +15.0 to +18.4. Next, this carrier was immersed in an 8% cupric chloride aqueous solution for 3 hours and dried at 120°C. The amount of copper chloride supported was 12% by weight. 30ml of the oxyhalogenation catalyst thus obtained
The oxychlorination reaction of ethylene was carried out using The reactor was made entirely of glass and had an inner diameter of 30 mm. A cyclone was attached to the upper part of the reactor, and a glass filter distribution plate was attached to the lower part to circulate the catalyst. This reactor was placed in a temperature-controlled sand bath, and oxychlorination reaction of ethylene was carried out at 260°C and normal pressure. As raw materials, ethylene, hydrogen chloride, and oxygen were supplied at a molar ratio of 2:4:1, and nitrogen was supplied at a total of 3.51 mol/hr so that the molar ratio of nitrogen:oxygen was 79:21. The results of the reaction were as shown in Table 1. The reaction was carried out continuously for 40 hours under these reaction conditions, but the catalyst activity was almost the same as at the beginning of the reaction.

[Table] Reacted ethi
Comparative Example 1 of Mole Number of Ren A catalyst in which 14.7% of cupric chloride was supported on γ-alumina (acid strength function Ho: −3.0 to +4.8) similar to that used in Example 1 was obtained by a dipping method. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 2.

[Table] Comparative Example 2 Phosphoric acid was added to γ-alumina similar to that used in Example 1 (acid strength function Ho is -3.0 to +4.8) by dipping at 15%.
wt% impregnated. The acid strength function Ho of this product was −3.0 to −8.2. 12% by weight of cupric chloride was supported on this carrier in the same manner as in Example 1. Using the catalyst thus obtained, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 3.

[Table] Example 2 γ-alumina similar to that used in Example 1 (acid strength function Ho: -3.0 to +4.8) was immersed in a 6% lithium hydroxide aqueous solution for 3 hours, dried, and impregnated with lithium hydroxide. A carrier having an amount of 9% by weight was obtained. The acid strength function Ho of this product was +6.8 to +15.0. Next, cupric chloride was supported on this carrier in the same manner as in Example 1, and oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 4.

【table】

[Table] Example 3 In Example 1, when 1.4% sodium hydroxide was used instead of 6% sodium hydroxide and the amount of sodium hydroxide impregnated was 2% by weight, the acid strength function Ho was +6.8.
An oxyhalogenation catalyst was obtained in the same manner as in Example 1, except that a support of ~+12.2 was obtained. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 5.

[Table] Example 4 γ-alumina similar to that used in Example 1 (acid strength function Ho: −3.0 to +4.8) was immersed in an 8% cupric chloride aqueous solution for 3 hours and dried. The amount of cupric chloride supported was 12% by weight. Next, this was immersed in a 1.4% aqueous sodium hydroxide solution and dried. The amount of sodium hydroxide impregnated was 2% by weight. Since the obtained catalyst was colored with a deep edge color by cupric chloride, it was impossible to measure the acid strength using the above-mentioned indicator. However, since the type of basifying agent and the amount of impregnation thereof are the same as in the carrier of Example 3, the acid strength function is also considered to be of the same level. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 6.

【table】

[Table] Example 5 γ-alumina similar to that used in Example 1 (acid strength function Ho: -3.0 to +4.8) was immersed in a 10% aqueous sodium hydroxide solution for 3 hours, and then dried at 120°C. . The amount of sodium hydroxide impregnated into the γ-alumina support is 15% by weight, and the acid strength function Ho is +15.0 to +26.5.
It was hot. Next, this carrier was immersed in an 8% cupric chloride aqueous solution for 3 hours and dried at 120°C. The amount of cupric chloride supported was 12% by weight. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 7.

[Table] Example 6 Acid strength function Ho of a 60 μm average particle diameter hook is -
Silica gel of 3.0 to +4.8 (specific surface area 320m ² /g)
immersed in 1.4% sodium hydroxide aqueous solution for 3 hours,
It was then dried at 120°C. The amount of sodium hydroxide impregnated into the silica gel carrier was 2% by weight, and the acid strength function
Ho was +6.8 to +12.2. Next, this carrier was immersed in an 8% cupric chloride aqueous solution and dried at 120°C. The amount of cupric chloride supported was 12% by weight. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 8.

【table】

[Table] Example 7 γ-alumina similar to that used in Example 1 (acid strength function Ho: -3.0 to +4.8) was immersed in a 2.5% barium hydroxide aqueous solution for 3 hours, and then dried at 120°C. . The amount of barium hydroxide impregnated into the γ-alumina support was 4% by weight, and the acid strength function Ho was +6.8 to +12.2. Next, this carrier was immersed in an 8% cupric chloride aqueous solution for 3 hours and dried at 120°C. The amount of cupric chloride supported was 12% by weight. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 9.

[Table] Example 8 γ-alumina similar to that used in Example 1 (acid strength function Ho: -3.0 to +4.8) was immersed in a 6% aqueous sodium hydroxide solution for 3 hours, and then dried at 120°C. . The amount of sodium hydroxide impregnated into the γ-alumina support is 9% by weight, and the acid strength function Ho is +15.0 to +18.4.
It was hot. The carrier was then immersed in an aqueous solution containing 8% cupric chloride and 1% potassium chloride for 3 hours and dried at 120°C. The supported amounts of cupric chloride and potassium chloride are 12% by weight and 1.5% by weight, respectively.
It was hot. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 10.

【table】

[Table] Example 9 γ-alumina (acid strength function Ho: −3.0 to +4.8) similar to that used in Example 1 was immersed in a 3% aqueous sodium carbonate solution for 3 hours, and then dried at 120°C. The amount of sodium carbonate impregnated into the γ-alumina support is
At 4.5% by weight, the acid strength function Ho was between +6.8 and +12.2. Next, this carrier was immersed in an 8% cupric chloride aqueous solution for 3 hours and dried at 120°C. The amount of cupric chloride supported was 12% by weight. Using this catalyst, oxychlorination of ethylene was carried out under the same conditions as in Example 1. The results are shown in Table 11.

[Table] Example 10 Using the catalyst used in Example 8, 1,2
-An oxychlorination reaction of dichloroethane was carried out. The glass reactor used in Example 1 was used as the reaction apparatus. The amount of catalyst used is 30ml
1 and 2, which have been gasified by heating in advance, are used as raw materials.
- dichloroethane, hydrogen chloride and oxygen in a molar ratio of 1:1:1.1 and nitrogen in a molar ratio of nitrogen:oxygen of 79:21;
2.79mol/hr was supplied. The results are shown in Table 12.

[Table] Comparative Example 3 The same γ-alumina used in Example 1 (acid strength function Ho: -3.0 to +4.8) was added to an aqueous solution containing 8% cupric chloride and 1% potassium chloride for 3 hours. Soaked and dried at 120°C. The supported amounts of cupric chloride and potassium chloride are 12% by weight and 1.5% by weight, respectively.
It was hot. Oxychlorination of 1,2-dichloroethane was carried out using this catalyst under the same conditions as in Example 10. The results are shown in Table 13.

【table】 [Brief explanation of drawings]

Figure 1 shows the acid strength function Ho of the alumina support,
It is a graph showing the relationship between carbon monoxide due to a combustion reaction and the selectivity (%) of carbon dioxide gas.

Claims (1)

[Claims] 1. An oxyhalogenation catalyst comprising cupric chloride supported on a basic carrier having a Hammett's acid strength function Ho of 6.8 or more. 2 The basicity of the carrier is Hammett's acid strength function Ho.
12 or more, the catalyst according to claim 1. 3. The catalyst according to claim 1, wherein the basic carrier is a basicized acidic carrier. 4. The catalyst according to claim 3, wherein the acidic carrier is alumina or silica. 5. The catalyst according to claim 3, wherein the basifying agent is an alkali metal hydroxide.