JPH0516415B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for dehydrochlorinating chlorinated saturated hydrocarbons having 2 or 3 carbon atoms (hereinafter abbreviated as C ₂ or C ₃ ). More specifically, the present invention relates to a method for dehydrochlorinating a chlorinated saturated hydrocarbon by contacting a catalyst made of zeolite, which is a type of crystalline aluminosilicate, with a C ₂ or C ₃ chlorinated saturated hydrocarbon. . The dehydrohalogenation reaction of halogenated saturated hydrocarbons, especially the dehydrochlorination reaction of chlorinated saturated hydrocarbons, is an industrially important reaction, and several types of industrial processes have been adopted. For example, vinyl chloride monomer is a raw material for plastics, but 1,
It is widely produced by dehydrochlorination through thermal decomposition of 2-dichloroethane (hereinafter abbreviated as EDC).
In this case, the dehydrochlorination reaction is usually carried out at a temperature above 500° C. and a pressure of about 50 kg/cm ² G. However, this method has a relatively low decomposition rate, requires complicated recovery steps for unreacted substances and separation of products, and requires high-temperature conditions, which consumes a lot of energy. It has the following disadvantages. We also produce chloroprene by dehydrochlorination of 3,4-dichlorobutene and 1,1,2-trichloroethane (hereinafter abbreviated as 1,1,2-TCE).
In the production of vinylidene chloride by dehydrochlorination, etc., a dehydrochlorination method using an aqueous sodium hydroxide solution or milk of lime is adopted. This method using an alkaline aqueous solution requires a large amount of alkaline aqueous solution for the stoichiometric reaction, which is economically disadvantageous, and furthermore, sodium chloride and calcium chloride produced as by-products must be disposed of. For these reasons, there is a strong desire in the industry to develop an economical dehydrohalogenation method as an alternative to conventional methods. Various zeolite catalysts have been proposed for catalytic dehydrohalogenation of halogenated saturated hydrocarbons. For example, JP-A-58-
Publication No. 167526 discloses a method using ZSM-5, silicalite, etc. as a catalyst. However, in this method, the activity of the catalyst used is not necessarily sufficient and the conversion rate of the raw material is therefore low, so the reaction temperature must be raised. Further, JP-A-54-79209 proposes a catalytic dehydrohalogenation process using a catalyst in which Y-type zeolite is treated or reacted with a Lewis acid. In the method of this reference, the zeolite used as a catalyst must be specially treated, and a complicated process is required from an industrial perspective. Furthermore, these references do not mention any zeolites other than ZSM zeolites or Y-type zeolites. In view of this situation, the present inventors conducted intensive studies on dehydrohalogenation methods, and found that zeolite with a specific crystal structure can be used in dehydrohalogenation reactions of halogenated saturated hydrocarbons, particularly in chlorinated saturated hydrocarbons. It was discovered that the present invention exhibits extremely high activity in the dehydrochlorination reaction of hydrocarbons, leading to the completion of the present invention. That is, the present invention relates to offretite-erionite zeolite (hereinafter abbreviated as OE zeolite).
and/or a method for dehydrochlorinating chlorinated saturated hydrocarbons, which comprises contacting a catalyst made of L-type zeolite with a C ₂ or C ₃ chlorinated saturated hydrocarbon. According to the method of the present invention, the catalyst used does not need to be subjected to any special treatment, and furthermore, since the catalyst used has extremely high dehydrohalogenation activity, especially dehydrochlorination activity, it is possible to significantly lower the reaction temperature. In addition, since the raw material conversion rate is high, the reaction raw materials and products can be easily separated. Therefore, the method of the present invention makes it possible to save energy to a large extent compared to the conventional method, and is extremely significant industrially. The present invention will be explained in more detail below. In the method of the invention, zeolites are used as catalysts, and zeolites are commonly referred to as crystalline aluminosilicates. Zeolites are composed of SiO ₄ tetrahedra and ALO ₄ tetrahedra, and many types are known due to differences in the bonding styles of each tetrahedron. The catalyst used in the method of the present invention is OE zeolite and/or L-type zeolite. Examples of OE zeolites include offretite and tetramethylammonium-offretite (hereinafter referred to as
TMA (abbreviated as offretite), erionite,
Furthermore, zeolites having both an offretite structure and an erionite structure can be mentioned, such as a new zeolite abbreviated as zeolite OE in Japanese Patent Publication No. 63-46006, zeolite T, and ZSM-34 zeolite. OE zeolite is a powder with a characteristic structure.
It has a line diffraction pattern, which allows it to be distinguished from other zeolites. Table 1 shows the powder X-ray diffraction pattern of the OE zeolite used as a catalyst in the present invention using a copper Kα doublet. Furthermore, OE-based zeolite generally has the following composition expressed in molar ratio of oxides. _M2 /nO・_AL2O3・(5~ ₁₀ ) _SiO2

【table】

[Table] (M is a cation with a valence of n.) Some OE-based zeolites exist naturally, but they can be synthesized, and the synthesis method is known. The OE-based zeolite used as a catalyst in the method of the present invention is preferably a synthetic zeolite with few impurities and a high degree of crystallinity. An example of a method for synthesizing TMA-offretite is the method disclosed in Japanese Patent Application Laid-Open No. 58-135123. In addition, as an example of a method for synthesizing OE-based zeolite containing a mixture of offretite and erionite structures,
The method disclosed in Japanese Patent Publication No. 46006 is further described in Japanese Patent Publication No. 50-23400 as an example of a method for synthesizing erionite, and Japanese Patent Publication No. 36-23400 as an example of a method for synthesizing zeolite T.
Examples of methods for synthesizing ZSM-34 zeolite include those disclosed in Japanese Patent Application Laid-Open No. 53-58499. L-type zeolite is a type of synthetic zeolite, and its typical composition, expressed as a molar ratio of oxides, is as shown in the following formula. (K ₂ , Na ₂ )O・AL ₂ O ₃・6.0SiO ₂ In addition, since L-type zeolite has a characteristic crystal structure, in powder X-ray diffraction measurement using a copper Kα doublet, it is shown in Table 2. It has a unique diffraction pattern. Methods for synthesizing L-type zeolite are known, for example, Japanese Patent Publication No. 63-1244,
Examples include methods disclosed in Japanese Patent Publication No. 46-35604, Japanese Patent Publication No. 36-3675, and the like. In the as-synthesized state, zeolite usually contains cations such as Na ions as metal cations. In the present invention, zeolite in this state can be used, but as described later, ion-exchanged zeolites with these metal cations can also be used as catalysts. It is known that the metal cations described above can be easily exchanged with other metal cations by ion exchange treatment. There are no particular restrictions on the exchangeable cations of the zeolite used in the method of the present invention, but each of alkali metals, alkaline earth metals, and rare earth metals

[Table] Preferably, it is one or more metal cations selected from metals. The metal cation can be easily introduced into zeolite by a known ion exchange treatment. That is, using water-soluble inorganic acid salts of metal cations such as hydrochloride and nitrate, or organic acid salts such as acetate and oxalate,
Prepare a 5mol/aqueous solution and incubate at a temperature of 20 to 100℃.
A method of performing ion exchange treatment for 0.5 to 24 hours. or,
The slurry is then filtered and the resulting solids are
Dry at 150°C for 1 to 24 hours. This method involves repeating the above operations several times. The ion exchange treatment may be performed by other methods, such as a method in which an aqueous solution containing the metal cation is circulated and brought into contact with a fixed bed made of the zeolite. In addition, when the synthesized zeolite contains an organic cation such as tetramethylammonium, it is preferable to remove the organic cation in advance in order to increase the ion exchange rate of the metal cation to be exchanged. For this purpose, pre-calcination may be performed as a pre-treatment for the ion exchange treatment, and this pre-calcination treatment may be performed at a temperature of 400 to 700° C. for 1 to 10 hours under air circulation. In the method of the present invention, there is no particular restriction on the shape of the catalyst, and a molded catalyst may be used, but it may also be used as a powder. The molding method may be a conventional method, such as a compression molding method, an extrusion molding method, a spray drying granulation method, etc. When molding, a substance inert to this reaction may be added as a binder or molding aid for the purpose of increasing its mechanical strength. For example, silica, alumina, silica-alumina, clay, graphite, stearic acid, starch, polyvinyl alcohol, etc.
%, preferably in the range of 2 to 30%. The catalyst obtained as described above is used after being subjected to a calcination treatment. Firing treatment is performed at 400-700℃ under air circulation.
You can do it for 10 hours. In the method of the present invention, the dehydrochlorination reaction of chlorinated saturated hydrocarbons can be carried out in a gas phase or a liquid phase, but a gas phase is preferred since it can be easily carried out at normal pressure. In this case, as a reaction method, conventionally known reaction methods such as a fixed bed flow method, a fluidized bed method, etc. can be adopted. Examples of the raw material C ₂ or C ₃ chlorinated saturated hydrocarbons include chloroethane, dichloroethanes such as 1,2-dichloroethane, trichloroethanes such as 1,1,2-trichloroethane, chloropropane, 1,2-dichloropropane, etc. and trichloropropanes such as 1,1,2-trichloropropane. Although it is difficult to uniformly specify reaction conditions, the reaction temperature is usually in the range of 150 to 400℃.
A range of 350°C to 350°C is particularly preferred. reaction temperature is 150
Below ℃, sufficient reaction rate cannot be obtained, and
When the temperature exceeds 400°C, energy consumption increases, which is not only economically disadvantageous, but also side reactions such as polymerization of products proceed. Further, there is no particular restriction on the reaction pressure, and the reaction can be carried out under normal pressure, reduced pressure, or increased pressure. The dehydrochlorination reaction can be carried out using chlorinated saturated hydrocarbon alone or in an inert atmosphere, and in order to obtain an inert atmosphere, the raw material may be diluted with nitrogen, helium, or the like. In that case, the concentration of the raw material is not particularly limited, but is preferably 1 to 99%, particularly 1 to 50%. In the method of the present invention, the contact time varies depending on the reaction method, conditions, etc., and it is difficult to specify it uniformly, but in the case of a fixed bed flow method, for example, the contact time is 10 to 10,000 hours at gas hourly space velocity (GHSV). ^-1 is good,
50 to 5000 hr ^-1 is particularly preferred. The product can be separated and purified from the production system by conventional methods, and unreacted chlorinated saturated hydrocarbons can also be recovered and recycled. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. It should be noted that the production rate shown in the Examples represents a numerical value calculated by the following formula. Production rate (%) = dehydrochlorination product (mol) / supply amount of chlorinated saturated hydrocarbon (mol) × 100 Example 1 Based on the method described in Japanese Patent Publication No. 1983-46006
We synthesized OE-based zeolite, zeolite OE. In other words, solid sodium hydroxide (NaOH:
93wt%) 23.6g, solid potassium hydroxide (KOH:
85wt%) 26.8g, sodium aluminate aqueous solution ( _Na2
Add 51.4 g of O: 19.2 wt%, AL ₂ O ₃ : 20.66 wt%) to make a homogeneous solution, then add 142.9 g of amorphous solid silica (white carbon manufactured by Nippon Silica Kogyo Co., Ltd.) while stirring well, and oxidize. A reaction mixture was obtained with the following composition in molar ratio of 3.9Na ₂ O・1.83K ₂ O・AL ₂ O ₃・18.8SiO ₂・382H ₂ O This was charged into an autoclave and heated at 150° C. for 40 hours while stirring at 250 rpm. The resulting slurry was separated into solid and liquid, thoroughly washed with water, and then heated at 150℃ for 5 minutes.
After drying for a period of time, a powder having the following composition was obtained. 0.21Na ₂ O・0.76K ₂ O・AL ₂ O ₃・7.4SiO ₂ As shown in Table 3, the powder X-ray diffraction pattern of this product was a new OE-based zeolite, zeolite OE. Note that powder X-ray diffraction was measured using a copper Kα doublet. This zeolite OE was subjected to K ion exchange treatment. Add 35 g of zeolite OE to 250 g of potassium chloride aqueous solution (1 mol/) and heat at 90°C for 5 hours.
Ion exchange treated. After that, the slurry was filtered, the obtained solid was thoroughly washed with water, and then heated to 120°C.
and dried for 16 hours. This K ion exchange zeolite
The powder X-ray diffraction pattern of OE remained almost unchanged;
The composition was 0.01Na ₂ O.0.98K ₂ O.AL ₂ O _{3.7.1SiO 2} . For K ion-exchanged zeolite OE, add silica sol (SiO ₂ : 30wt%) as a binder to 20wt%, add an appropriate amount of water, evaporate to dryness with stirring, and after grinding graphite to 5wt%. It was then compression molded to a size of 5 mmφ x 5 mmL.
This catalyst was calcined at 540° C. for 3 hours under air circulation. The dehydrochlorination reaction of EDC was carried out using this catalyst. Fill a Pyrex reaction tube (20 mmφ x 500 mmL) with 19.3 ml of catalyst, and
Raw material gas containing 10 vol% EDC and 90 vol% nitrogen was supplied. Reaction conditions are normal pressure, 300℃, GHS.V=600h ^-1
It is. All reaction products were quantified by gas chromatography. The results are shown in Table 5. Example 2 Erionite was synthesized according to the method described in Japanese Patent Publication No. 50-23400. Sodium aluminate aqueous solution (Na ₂ O: 18.8wt%, AL ₂ O ₃ : 21.8wt%), solid sodium hydroxide (NaOH: 93.wt%), solid potassium hydroxide (KOH: 85wt%), chloride A reaction mixture represented by the following formula was prepared from a benzyltrimethylammonium aqueous solution (benzyltrimethylammonium chloride: 60wt%), colloidal silica gel ( _SiO2 : 30wt%), and pure water. 0.8R ₂ O・10.3Na ₂ O・1.2K ₂ O・AL ₂ O ₃・ 28.6SiO ₂・465H ₂ O (R represents benzyltrimethylammonium cation) This reaction mixture was stirred for about 5 hours and then autoclaved. and heated at 100℃ for 13 days. The resulting slurry was filtered, and the resulting powder was thoroughly washed with water and then dried at 110°C for 2 hours. This powder has a composition expressed in molar ratio of oxides as 0.04R ₂ O・0.52Na ₂ O・0.44K ₂ O・AL ₂ O ₃・6.9SiO ₂ , and the powder X-ray diffraction pattern is shown in Table 1. It was confirmed that it was erionite. In order to remove benzyltrimethylammonium cations, preliminary calcination treatment was performed at 540° C. for 5 hours under air circulation, and then K ion exchange treatment was performed in the same manner as in Example 1. As a result, erionite 0.01Na ₂ O.0.98K ₂ O.AL ₂ O 3.6.9SiO ₂ having _a composition as shown in the following formula was obtained. This K ion-exchanged erionite was used as a catalyst using the same preparation method as in Example 1. Using this catalyst, dehydrochlorination reaction of EDC was carried out under the same reaction conditions as in Example 1. The results are shown in Table 5. Example 3 According to the description in JP-A-58-135123,
TMA offretite was synthesized. Amorphous solid silica (white carbon manufactured by Nippon Silica Kogyo Co., Ltd.), aqueous sodium aluminate solution (Na ₂ O: 18.8 wt%, AL ₂
A reaction mixture represented by the following formula was prepared from solid sodium hydroxide (NaOH: 93 wt%), solid potassium hydroxide (KOH: 85 wt%), tetramethylammonium _hydroxy and pure water. . 0.39(TMA) ₂ O・5.57Na ₂ O・1.15K ₂ O・AL ₂
O ₃ .17.6SiO ₂ .325H ₂ O (here, TMA represents tetramethylammonium) This reaction mixture was placed in an autoclave equipped with a stirrer and crystallized at 170° C. for 5 minutes while stirring at a wind speed of 1 m/sec. The resulting slurry was filtered, and the resulting powder was thoroughly washed with water and then dried at 110°C for 2 hours.
This powder has a composition of 0.33(TMA) _2O・_0.27Na2O・_0.40K2O・_AL2O3・_7.4SiO2 , and _the powder X-ray diffraction measurement results match the pattern in Table 1. , was confirmed to be TMA-offretite. In order to remove TMA ions, which are organic cations, a preliminary calcination treatment was performed at 540° C. for 3 hours under air circulation, and then a K ion exchange treatment was performed in the same manner as in Example 1. As a result, offretite having a composition as shown in the following formula was obtained. _{0.01Na 2 O. _ _} A hydrogen reaction was carried out. The results are shown in Table 5. Example 4 A sulfuric acid acidic aluminum sulfate aqueous solution (AL ₂ O ₃ =
4.44w/v%, H ₂ SO ₄ = 25.69w/v%) and sodium silicate aqueous solution (Na ₂ O = 6.56w/v%, SiO ₂ =
20w/v%, AL ₂ O ₃ =0.22w/v%) respectively.
The reactants were fed simultaneously and continuously at feed rates of 0.25/hr and 0.75/hr, and the reaction was carried out under stirring. The residence time of the reaction slurry was 30 minutes, the pH was 6.2, and the reaction temperature was 32°C. The slurry product overflowing from the reaction tank was separated into solid and liquid and washed with water to obtain an amorphous compound having the following composition. Na ₂ O (dry base) 5.2wt% AL ₂ O ₃ (dry base) 7.13wt% SiO ₂ (dry base) 87.7wt% H ₂ O (wet base) 59.7wt% Add the above to 176g of 16.4wt% potassium hydroxide aqueous solution 142.2 g of the amorphous compound was added and stirred to prepare a slurry-like reaction product. This reaction mixture was charged into an autoclave and heated at 170°C under its autogenous pressure.
Crystallization was performed by holding for 24 hours. After the reaction was completed, the produced solid was separated, washed with water, and then dried at 110°C. Chemical analysis of this product revealed that its composition _, expressed in molar ratio of oxides, was 0.99K ₂ O.0.01Na ₂ O.AL ₂ O 3.6.0SiO ₂ . As shown in Table 4, the powder X-ray diffraction pattern of this sample almost coincides with that in Table 2,
It was confirmed that it was L-type zeolite. The L-type zeolite thus obtained was molded and calcined according to the method shown in Example 1, and the dehydrochlorination reaction of EDC was carried out at a reaction temperature of 300° C. under the same conditions as in Example 1. The results are shown in Table 5. Example 5 Zeolite OE obtained in Example 1 was treated in the same manner as in Example 1 without ion exchange, and treated in the same manner as in the same example.
The dehydrochlorination reaction of EDC was carried out. 5th result
Shown in the table. Comparative Example 1 A zeolite similar to ZSM-5 was synthesized according to the method described in Japanese Patent Application No. 57-162123.
As a result of elemental analysis after washing with water and drying, it had the following composition. 1.05Na ₂ O.AL _{2 O} 3.23.3SiO ₂ This zeolite similar to ZSM-5 was prepared as a catalyst in the same manner as in Example 1. Using this catalyst, EDC dehydrochlorination reaction was carried out under exactly the same reaction conditions as in Example 1. The results are shown in Table 6. Comparative Example 2 EDC dehydrochlorination reaction was carried out under exactly the same reaction conditions as in Example 1 using commercially available mordenite type (H type). The results are shown in Table 6. Comparative Example 3 Ferrierite was synthesized according to the method described in Japanese Patent Publication No. 2-47403. As a result of elemental analysis after washing with water and drying, it had the following composition. 1.00Na ₂ O.AL ₂ O _{3.17.3SiO 2} This ferrierite was made into a catalyst in exactly the same manner as in Example 1. Using this catalyst, EDC dehydrochlorination reaction was carried out under exactly the same reaction conditions as in Example 1. The results are shown in Table 6. Comparative Example 4 Clinoptilolite (produced by Itaya) was used as a catalyst in the same manner as in Example 1. Using this catalyst, EDC dehydrochlorination reaction was carried out under exactly the same reaction conditions as in Example 1. The results are shown in Table 6. Comparative Example 5 Commercially available Y-type zeolite (H-type) was heated under air circulation.
Firing treatment was performed at 540°C for 3 hours. Using this,
The reaction temperature was 250°C and the other conditions were the same as in Example 1.
The dehydrochlorination reaction of EDC was carried out. The results are shown in Table 6. Examples 6 to 11 Using the zeolite OE synthesized in Example 1, Na ions,
Rb ion, Cs ion, Mg ion, Ca ion,
A catalyst ion-exchanged with La ions was obtained. Fill a reaction tube with 19.3 ml of these catalysts and set the reaction temperature to 250~
EDC dehydrochlorination reaction was carried out at 300° C. under the same conditions as in Example 1 except for the following conditions. The results are shown in Table 7. Example 12 Using the catalyst prepared in Example 4, the reaction temperature was 250
Dehydrochlorination reaction of 1.1.2-TCE was carried out at 1.1.2-TCE under the same conditions as in Example 1 except for the following conditions. 1.2-dichloroethyl

【table】

【table】

【table】

【table】

【table】

[Table] The production rate of Ren was 66.7%. Example 13 Using the catalyst prepared in Example 1, the reaction temperature was 275
The dehydrochlorination reaction of EDC was carried out at 0.degree. C. under the same conditions as in Example 1. The production rate of vinyl chloride is 69.0%
It was hot. Additionally, 0.3% of ethylene is produced as a by-product.
% produced. Example 14 Using the catalyst prepared in Example 6, the reaction temperature was 275
The dehydrochlorination reaction of EDC was carried out at 0.degree. C. under the same conditions as in Example 1. The production rate of vinyl chloride is 77.6%
It was hot. Additionally, 0.3% of ethylene is produced as a by-product.
% produced.

Claims (1)

[Claims] 1. A method for producing chlorinated saturated hydrocarbons, characterized by contacting a catalyst made of offretite-erionite zeolite and/or L-type zeolite with a chlorinated saturated hydrocarbon having 2 or 3 carbon atoms. Dehydrochlorination method. 2. The method according to claim 1, wherein the exchangeable cation of the zeolite is one or more metal cations selected from the metal group consisting of alkali metals, alkaline earth metals, and rare earth metals. 3. The method according to claim 1 or 2, wherein the chlorinated saturated hydrocarbon is 1,2-dichloroethane or 1,1,2-trichloroethane.