JPH03262539A - Method and catalyst for producing aromatic hydrocarbon - Google Patents

Abstract

PURPOSE:To produce an aromatic hydrocarbon in a high conversion rate with high selectivity by bringing an aliphatic hydrocarbon and/or alicyclic hydrocarbon into contact with platinum-containing crystalline gallosilicate obtained by crystallizing a mixture containing a silicon compound and the like. CONSTITUTION:A mixture consisting of a silicon compound, a gallium compound, a platinum compound, an alkali metal salt and water is crystallized to form platinum-containing crystalline gallosilicate having such a structure that aluminum of ZSM-5 type zeolite is substituted with gallium and platinum. This catalyst is used to obtain an aromatic hydrocarbon from a 2-7C aliphatic hydrocarbon and/or alicyclic hydrocarbon in a high conversion rate with high selectivity.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to converting a raw material mainly composed of an aliphatic hydrocarbon and/or alicyclic hydrocarbon having 2 to 7 carbon atoms into a platinum-containing crystalline material. The present invention relates to a method for producing aromatic hydrocarbons by contacting them with gallosilicate, and a catalyst thereof.

[Prior Art] Many methods have been proposed for converting aliphatic hydrocarbons and/or alicyclic hydrocarbons into aromatic hydrocarbons for the purpose of reforming petroleum products, etc. Among them, zeolite ZSM-5 There is already a known method for converting hydrocarbons consisting of paraffins, olefins, and/or naphthenes into aromatic compounds using a zeolite catalyst called gallosilicate, which has a structure in which aluminum is replaced with gallium, or a catalyst in which platinum is supported on the zeolite catalyst. (Japanese Unexamined Patent Publication No. 62-81329).

[Problems to be Solved by the Invention] However, since gallosilicate has low activity, the conversion rate of feedstock hydrocarbons is low. Catalysts with platinum supported on them have high activity and give a high conversion rate, but they have the disadvantage of low selectivity to aromatic hydrocarbons because they produce a lot of lower paraffins such as ethane and propane as by-products.

The present inventors have conducted intensive studies on catalyst poisoning for producing aromatic hydrocarbons with high selectivity and high conversion rate from aliphatic hydrocarbons and/or alicyclic hydrocarbons having 2 to 7 carbon atoms. As a result, a crystalline gallosilicate containing platinum is obtained by crystallizing a mixture containing a silicon compound, a gallium compound, and a platinum compound, and has a structure in which the aluminum of ZSM-5 type zeolite (aluminosilicate) is replaced with gallium and platinum. was found to be a catalyst with high activity and high aromatic selectivity.

[Means for Solving the Problems] That is, the present invention provides an aliphatic hydrocarbon and/or alicyclic hydrocarbon having 2 to 7 carbon atoms obtained by crystallizing a mixture containing a silicon compound, a gallium compound, and a platinum compound. A method for producing an aromatic hydrocarbon, which is characterized in that it is brought into contact with a crystalline gallosilicate containing platinum; .100
For the production of aromatic hydrocarbons, the crystalline gallosilicate containing platinum obtained by holding at a temperature of ~220°C for 3 to 200 hours is fired as an acid form, or is made into an acid form after firing. It is a catalyst.

Crystalline aluminosilicates containing cations are known as zeolites in natural and synthetic forms. Aluminosilicate has a three-dimensional skeletal structure in which Si 2 O 4 tetrahedrons and Al 2 O 4 tetrahedra are crosslinked by sharing oxygen atoms, and the ratio of aluminum and silicon atoms to oxygen atoms is 1:2.

On the other hand, the platinum-containing crystalline gallosilicate used in the present invention has a structure in which the aluminum of aluminosilicate ZSM-5 is replaced with gallium and platinum, and silicon, gallium, and platinum atoms share oxygen and cross-link to form a crystalline gallosilicate. It has the same skeletal structure as aluminosilicate. All silicon, gallium, or platinum atoms do not necessarily have to constitute the same crystal structure, and some of them may coexist in other forms such as oxides or ions.

S in crystalline gallosilicate containing platinum of the present invention
The atomic ratio of i/P or the atomic ratio of Si/Ga is not particularly limited, but is preferably Si/pt.
The atomic ratio of Si/Ga can be in the range of 100 to 220, and the atomic ratio of Si/Ga can be in the range of 15 to 1000.

When the atomic ratio of S i / P t is less than 100, the utilization efficiency of platinum in the catalyst is low;
If it is larger, the activity of the catalyst will not be sufficient.

Furthermore, if the atomic ratio of S i /G a is smaller than 15, crystal formation is poor and the catalyst deteriorates quickly over time. On the other hand, if the atomic ratio is greater than 1000, the aromatic selectivity will be low.

The platinum-containing crystalline gallosilicate used in the present invention preferably has an X-ray diffraction pattern shown in Table 1 similar to ZSM-5 type zeolite.

Table 1 Powder X-ray diffraction lattice spacing of aluminozine cosilicate (
d value) Relative strength 11.2 ± 0.3 strong 10.1 ± 0, 3 strong 5.99 ± 0.2 weak 5.58 ± 0.1 weak 5.02 ± o, i weak 4.62 shi 0908 Weak 4.27±0.08 Weak 3.85±0.07 Strong 3.72±0.05 Strong 3.65±0.05 Weak 3.05±0.03 Weak 2.99±0.03 Weak Platinum Crystalline gallosilicate containing silicon compounds, gallium compounds, platinum compounds, alkali metal salts, water,
Then, optionally, an organic nitrogen compound and an acid are mixed, and p
H9-12, 3-200℃ at a temperature of 100℃-220℃
It can be synthesized over time.

As an example of the silicon compound, sodium silicate, potassium silicate, silica, or a mixture of two or more of these can be used.

As the gallium compound, gallium sulfate, gallium nitrate, gallium chloride, gallium hydroxide, gallium oxide, or a mixture of two or more of these can be used.

As the platinum compound, monochloroplatinic acid, dichloroplatinic acid, their sodium salts, potassium salts, ammonium salts, tetraamine dichloroplatinum, or a mixture of two or more of these can be used.

As the alkali metal salt, sodium or potassium hydroxide, chloride, bromide, sulfate, nitrate, acetate, or a mixture of two or more of these can be used.

As organic nitrogen compounds, tetrapropylammonium,
Quaternary ammonium hydroxides, bromides, such as tetrabutylammonium and tripropylmethylammonium,
Chlorides or amines such as tripropylamine, tributylamine, morpholine, amino alcohols such as triethanolamine and jetanolamine, amides such as acetamide and propionamide, methylurea,
Alkylureas such as 1,3-dimethylurea, nitriles such as acetonitrile and propionitrile, or mixtures of two or more thereof can be used.

As the acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, phosphoric acid, or a mixture of two or more of these can be used.

The raw materials are not limited to those exemplified here.

The synthesized platinum-containing gallosilicate is ion-exchangeable and can be used by exchanging most of the cations with H'-ions. Prior to exchange, the synthesized platinum-containing crystalline gallosilicate is heated, e.g.
It may be baked at ℃.

H'''' ion exchange can be carried out by immersing the material in an aqueous solution such as nitric acid, hydrochloric acid, or sulfuric acid, or by immersing it in an aqueous ammonium salt solution and firing the product that has been exchanged with ammonium ions. In these ion exchanges, It may also be immersed in an aqueous solution to remove gas by heating, reducing pressure, or the like.

Crystalline gallosilicate containing platinum can be used as is,
Alternatively, it can be used as a catalyst by adding a granulating agent and molding it. Granulating agents include silica, alumina, clay,
Generally known materials such as inorganic salts, organic polymers, and surfactants can be used.

Such crystalline gallosilicate containing platinum is used as a catalyst for producing aromatic hydrocarbons from aliphatic hydrocarbons and/or alicyclic hydrocarbons having 2 to 7 carbon atoms.
Examples of aliphatic hydrocarbons having 2 to 7 carbon atoms include ethane, propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, n-hexane, methylpentane, dimethylbutane, n-hebutane. , saturated hydrocarbons such as methylhexane, dimethylpentane, ethyreta, propylene, butene, butadiene, pentene, pentadiene,
Includes unsaturated hydrocarbons such as hexene, hexadiene, heptene, heptadiene, cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, heclohebutene, cyclohexadiene, methylcyclohexadiene.

Examples of alicyclic hydrocarbons include cyclobencune, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, and ethylcyclopenkune.

The raw material supplied to the reaction contains at least 50% by weight of the above aliphatic hydrocarbons and/or alicyclic hydrocarbons having 2 to 7 carbon atoms, and contains components other than the above, such as benzene, toluene, and carbon atoms. There is no problem even if hydrocarbons of Ca or higher, methanol, dimethyl ether, etc. are mixed.

The aromatization reaction is suitably carried out at a temperature range of 350 to 600°C. If the reaction temperature is lower than 350°C, the yield of aromatic hydrocarbons will be insufficient, while if it is higher than 600°C, the catalyst performance will deteriorate rapidly due to coke formation. The feed rate of the raw materials depends on the composition of the raw materials, the reaction temperature, and the type of catalyst, but it is appropriate that the weight hourly space velocity is in the range of 0.1 to 10 Hr-'. If the weight hourly space velocity is less than 0.1 Hr'', the production efficiency of aromatic hydrocarbons will be low, while if it is greater than 10 Hr-', the yield of aromatic hydrocarbons will be insufficient.

The pressure of aromatization reaction is 0-10 kg/c rr
A pressure of r.G is appropriate. At a pressure of 10 kg/crrf·6 or more, the yield of aromatic hydrocarbons is not high. The aliphatic hydrocarbon having 2 to 7 carbon atoms, which is a raw material for the reaction, may be supplied as it is, or may be supplied together with hydrogen, nitrogen, or carbon dioxide.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Length 1 glue 1 Add 26 g of sodium chloride and 1.9 g of tetrapropylammonium bromide to 104 mJ2 of distilled water, add 1.91 g of gallium sulfate, 0.49 g of tetraamine dichloroplatinum, and 1.9 g of tetrapropylammonium bromide to 60 m12 of distilled water. A in which 5.6g and 5.3g of concentrated sulfuric acid were dissolved.
The solution and Solution B, which was prepared by dissolving 69 g of Water Glass No. 3 in 45 mβ of distilled water, were added simultaneously and continuously while stirring.

At that time, sodium hydroxide or sulfuric acid was added to adjust the pH of the mixture to maintain it at 1O.

The gel was recovered from this mixture by centrifugation, soaked for 1 hour, and combined with the supernatant obtained by centrifugation. The mixture was transferred to an autoclave and heated to 160°C over 1 hour, and then heated from 160°C to 210°C over 250 minutes while stirring. After cooling, take out the solid matter, wash it with water, and dry it.
18 g of platinum-containing gallosilicate having the lattice spacing according to the X-ray diffraction diagram shown in Table 1 was obtained by firing at .degree. This was immersed in an ammonium nitrate aqueous solution to replace the cations with NH4+ ions, and was calcined at 540° C. for 3.5 hours to form an H-type catalyst A. Atomic ratio S at this contact μ
i/Pt is 220. Si/Ga was 20.

Next, the reaction raw material n-butane was diluted with nitrogen to 20 vol % in a reactor filled with catalyst A and maintained at 500° C., and the mixture was passed through the reactor at a gas hourly space velocity of 2000 Hr −′ to carry out an aromatization reaction. The reactor outlet gas was collected and analyzed for its composition by gas chromatography, and from the analyzed values, the n-butane conversion rate and selectivity of each product were calculated using the following equations.

Selectivity of individual products n-butane conversion and selectivity of each product are shown in Example 2.3.
It is shown in Table 2 together with Comparative Examples 1 to 3.

The aromatization reaction was carried out in the same manner as in Example 1, except that the same catalyst A as in Example 1 was used and the raw hydrocarbon was replaced with propane from n-butane, and the conversion rate of propane was calculated. This is referred to as Example 2.

Similarly, n-butane in Example 1 was replaced with ethane, and the aromatization reaction was carried out. This is referred to as Example 3. The results are shown in Table 2.

The catalyst was H-type gallosilicate prepared in the same manner as in Example 1 except that no tetraamine dichloroplatinum was added. Catalyst B is prepared by soaking a catalyst in an aqueous tetraamine dichloroplatinum solution to support 0.5% by weight of platinum.

Comparative Example 1 was obtained by carrying out the aromatization reaction of n-butane in the same manner as in Example 1 except that catalyst B was used instead of catalyst A.
Comparative Example 2 is a sample in which the aromatization reaction of propane was carried out in the same manner as in Example 2, and Comparative Example 3 is in which the aromatization reaction of ethane was carried out in the same manner as in Example 3. The results are shown in Table 2.

Although the aromatization reaction using Catalyst B has a high conversion rate, compared to Catalyst A of the present invention, more lower paraffins are produced as by-products, and the selectivity to aromatic hydrocarbons is not sufficient. Furthermore, Catalyst A produces more olefins than Catalyst B, and this olefin is a more preferable raw material for the aromatization reaction than lower paraffins, and increasing the contact time improves the selectivity of aromatic compounds. can be expected.

Example 4 is an example in which the aromatization reaction of propane was carried out using Catalyst A in the same manner as in Example 2 except that the reaction temperature was changed to 600°C. Similarly, the reaction temperature was set to 550°C and 500°C.
Examples 5 and 6 are the results obtained in Example 5 and 6. The conversion rate and product selectivity in Example 4 are shown in Table 3 together with Example 7 and Comparative Examples 4.8. Further, the relationship between reaction temperature and conversion rate is shown in A of FIG.

A catalyst was prepared in the same manner as in Example 1 except that 0.46 g of sodium dichloroplatinate was used instead of 0.49 g of tetraamine dichloroplatinum, and this was designated as catalyst C.

The SL/Pt ratio of this catalyst was 100.

Example 4.5. but using catalyst C instead of catalyst.
Table 3 shows the conversion rate and product selectivity in Example 7, in which Examples 7, 8, and 9 were obtained by aromatizing propane in the same manner as in Example 6. Further, the relationship between reaction temperature and conversion rate is shown in C of FIG.

Comparative Examples 4 and 5.6 were obtained by carrying out the aromatization reaction of propane in the same manner as in Examples 4 and 5.6, except that Hikasa Ai±Nu Catalyst B was used. Further, Comparative Example 7 is a reaction conducted at a reaction temperature of 450°C. The conversion rate and product selectivity in Comparative Example 4 are shown in Table 3, and the relationship between reaction temperature and conversion rate is shown in FIG. 1B.

The ratio is 1 and 1.

The aromatization reaction of propane was carried out in the same manner as in Comparative Examples 4, 5, and 6.7 except that a catalyst was used, and Comparative Example 8 was obtained.
, 9, 10.11. The conversion rate and product selectivity in Comparative Example 8 are shown in Table 3, and the relationship between reaction temperature and conversion rate is shown in D of FIG.

[Effects of the Invention] The present invention uses a catalyst containing crystalline gallosilicate containing platinum, which is obtained by adding a platinum compound and performing a crystallization reaction. This is an industrially advantageous method for obtaining aromatic hydrocarbons from hydrocarbons with a high conversion rate and aromatic selectivity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between reaction temperature and propane conversion rate in propane aromatization reactions using various catalysts of the present invention and conventional methods.

Claims (1)

[Scope of Claims] (1) Contains platinum obtained by crystallizing a mixture containing a silicon compound, a gallium compound, and a platinum compound from an aliphatic hydrocarbon and/or alicyclic hydrocarbon having 2 to 7 carbon atoms. A method for producing aromatic hydrocarbons, which comprises bringing them into contact with crystalline gallosilicate. (2) The method for producing aromatic hydrocarbons according to claim 1, wherein the crystalline gallosilicate containing platinum has a powder X-ray diffraction pattern shown below. Lattice spacing (d value): Relative strength 11.2±0.3: Strong 10.1±0.3: Strong 5.99±0.2: Weak 5.58±0.1: Weak 5.02± 0.1: Weak 4.62 ± 0.08: Weak 4.27 ± 0.08: Weak 3.85 ± 0.07: Strong 3.72 ± 0.05: Strong 3.65 ± 0.05: Weak 3.05±0.03: Weak 2.99±0.03: Weak (3) A mixed solution consisting of a silicon compound, a gallium compound, a platinum compound, an alkali metal salt, and water is heated to a pH of 9 to 12.
For the production of aromatic hydrocarbons, the crystalline gallosilicate containing platinum obtained by holding at a temperature of 100 to 220°C for 3 to 200 hours is fired as an acid form, or is made into an acid form after firing. catalyst.