JPH0678249B2 - Method for producing polyalkylbenzene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing polyalkylbenzene. More specifically, a crystalline aluminosilicate modified by a modifier containing one or more compounds selected from the group consisting of heteropolyacids and heteropolyacid salts (hereinafter collectively referred to as heteropolyacid compounds) is used as a catalyst. , A dialkylbenzene and / or a trialkylbenzene are alkylated to produce a polyalkylbenzene.

[Conventional technology]

Crystalline aluminosilicate is a porous substance known as zeolite (hereinafter, crystalline aluminosilicate may be referred to as zeolite). Specific examples thereof include natural zeolites such as mordenite, siavacite, and erionite, and synthetic zeolites such as A-type, L-type, and Y-type that are hydrothermally synthesized from raw materials such as silica component, alkali component, and water. . Furthermore, regarding the synthetic zeolite, zeolites having a skeleton structure different from that of natural zeolites such as ZSM-5 and ZSM-11 have been produced in recent years. Especially ZSM-crystallized in the presence of organic amines
No. 5 is obtained as a crystalline phase in a wide range of silica / alumina molar ratio, and is noted as a unique and useful zeolite.

Moreover, since the zeolite is porous as described above, and its crystal skeleton forms a regular cage structure,
It is also known that when this is used as a catalyst, it exhibits shape selectivity of a molecular unit with respect to a substance participating in the reaction. That is, since the zeolite is porous, the surface area inside the cage is about 100 times larger than the outer surface area, and the reaction fields of molecules that can pass inside the cage and molecules that cannot pass inside the cage are greatly different. Molecules that can pass through react selectively.

Further, it is known that zeolite undergoes various modification treatments such as proton exchange and cation exchange with rare earth elements, and exhibits much higher catalytic activity than conventional solid acids such as silica-alumina.

As described above, zeolite has various excellent characteristics, and therefore is an extremely important substance industrially as a catalyst or an adsorbent, and technological developments relating to zeolite are being advanced in various industrial fields.

By the way, industrially useful aromatic compounds are contained in cracked gasoline produced when catalytically modified oil or naphtha in petroleum refining is cracked to produce ethylene or propylene. It goes without saying that benzene, orthoxylene, and paraxylene are industrially important aromatic compounds. On the other hand, C ₉ and C ₁₀ aromatic compounds, for example, pseudoquineum and deurene, are also increasing their importance recently as intermediates for raw materials such as solvents, dye intermediates, paints, special plasticizers and synthetic resins. is there. However, for example, deurene contained in the C ₁₀ fraction of the catalytic reforming oil is only about 8% by weight, and its boiling point is close to that of other C ₁₀ aromatic compounds. It is very difficult to separate. Also, since the melting point of deurene is higher than that of other isomers at 79 ° C, it can be separated by crystallization, but it is energetically disadvantageous when the concentration of deurene is low. Is. Therefore, various methods have been proposed for synthesizing polyalkylbenzenes such as pseudoquinene and deurene by contacting benzene, toluene, dialkylbenzenes and trialkylbenzenes having 8 and 9 carbon atoms with an alkylating agent in the presence of a solid catalyst. . For example, Journal of Japan Petroleum Institute Vol. 28, No. 1, 13
On page 18 (1985), a method for synthesizing tetramethylbenzene from trimethylbenzene and methanol using HZSM-5 type zeolite as a catalyst is shown. In addition, JP-A-57
JP-A-48925 discloses a method for producing trimethylbenzene from paraxylene and methanol using a metal-substituted Y-type zeolite as a catalyst.

The inventors of the present invention made additional tests on the prior art of producing tetramethylbenzene by using various types of zeolite such as Y-type, mordenite-type, pentasil-type, etc. as catalysts, and found the following. That is, a catalyst based on pentasil-type zeolite has a good selectivity for deurene, but the conversion rate of trimethylbenzene as a raw material is low and the change in catalytic activity over time (activity deterioration) is large. Of the mordenite type does not show a satisfactory value, and the mordenite type shows a stable catalytic activity over time at a relatively high raw material conversion rate, but easily produces a high boiling component by a side reaction.

[Problems to be solved by the invention]

The inventors of the present invention have conducted earnest research on the problems of the above-mentioned prior art, particularly on a method for producing polyalkylbenzene in order to reduce the production of by-products. As a result, they have found that a crystalline aluminosilicate treated with a modifier containing a heteropolyacid compound can suppress side reactions in the alkylation reaction of dialkylbenzene and / or trialkylbenzene, and arrived at the present invention.

[Structure of Invention]

That is, in the present invention, an aromatic compound containing a dialkylbenzene and / or a trialkylbenzene and an alkylating agent are converted into a modifying agent containing one or more compounds selected from heteropolyacid compounds in the presence of hydrogen. Using a crystalline aluminosilicate that has been treated as a catalyst,
The present invention relates to a method for producing polyalkylbenzene, which comprises reacting.

The zeolite used in the present invention may be either synthetic or natural as long as it is a mordenite type. Further, depending on the purpose of use, proton type, ammonium salt type, various metal salt types obtained by cation exchange, or those which have been appropriately treated such as dealumination can be used. Incidentally, zeolites other than mordenite type zeolite can be appropriately contained within a range that does not affect the catalytic reaction.

In the present invention, the heteropolyacid is a general term for an acid produced by condensing two or more kinds of inorganic oxygen acids, and is coordinated via the central heteroatom (group I to VIII element) of the heteropolyacid anion and oxygen. It can take various forms depending on the combination with a poly atom (usually Mo, W, Nb, V, etc.).

In the present invention, any heteropoly acid can be used without any trouble. Specifically, for example, 12-tungstophosphoric acid (H ₃ PW
₁₂ O ₄₀ ), 12-Tungstosilicic acid (H ₄ SiW ₁₂ O ₄₀ ), 12-
Molybdophosphate _{(H 3 PMo 12 O 40)} , 12- tongue strike germanate acid _{(H 3 GeW 12 O 40)} , 12- molybdate de germanate acid (H ₃ Gemo
₁₂ O ₄₀ ) etc. can be mentioned.

Further, the heteropolyacid salt used in the present invention includes ammonium salts, alkali metal salts, alkaline earth metal salts and other metal salts of the above heteropolyacid.

These heteropolyacids or heteropolyacid salts are dissolved in a solvent inert to zeolite and these heteropolyacid compounds and used for treating zeolite. From the viewpoint of industrial practice, it is preferable to use a solvent having a high solubility as the solvent. Examples of the preferable suitable solvent include water, alcohol, ether, ketone and the like,
From the viewpoint of industrial practice, it is more preferable to use water.

Also, the hydrogen ion concentration of the denaturing agent at the time of denaturing treatment is low to prevent the heteropoly acid, which is strongly acidic, from deteriorating.
It is preferably carried out in the region.

The modification treatment can be performed by various known means such as a dipping method and a spraying method. The temperature at that time may be a temperature at which the heteropolyacid compound does not decompose, and is preferably about 10 to 90 ° C. in the dipping method from the viewpoint of easy treatment. Of course, it is also possible to directly spray the zeolite at a temperature at which the heteropolyacid compound does not decompose. However, it suffices for the modification treatment to substantially bring the zeolite and the modifier into contact, and the immersion method is industrially preferable.

In the present invention, the heteropolyacid compound used for modifying the zeolite is preferably used in an amount of about 5 to 50% by weight with respect to the zeolite. The contact time between the zeolite and the modifier is about 30 minutes to 50 hours, and preferably about 3 to 10 hours.

The zeolite modified with the heteropolyacid compound is then subjected to calcination. The calcination is carried out in the presence of oxygen or air, and the temperature may be in the range where the heteropolyacid compound is decomposed and the zeolite is not deteriorated. For example, a firing temperature of about 400 to 650 ° C. and a firing time of about 1 to 20 hours are suitable. The modification with the heteropolyacid compound and the firing may be repeated several times.

Further, the catalyst used in the present invention may have any shape, but it is preferably a molded product from a practical viewpoint.
A binder may be used when molding is performed. As the binder, a very general one such as alumina sol, silica sol, clay or the like can be used. The amount of the binder used is not particularly limited, but it is preferable to use about 5 to 30% by weight with respect to the zeolite. The molded catalyst is subjected to calcination again. The firing in this case is also carried out under exactly the same conditions as the firing described above.

The catalyst used in the present invention is obtained by modifying the crystalline aluminosilicate with a heteropolyacid compound by the above method. However, the modification treatment may be carried out before molding the crystalline aluminosilicate or after molding, as long as the crystalline aluminosilicate is substantially modified.

The method of the present invention uses the catalyst prepared as described above to produce polyalkylbenzene. The raw material is an aromatic compound containing dialkylbenzene and / or trialkylbenzene. Of course, benzene and / or monoalkylbenzenes, such as toluene, may be included as these will eventually be converted to polyalkylbenzene by the process of the invention. Further, a non-aromatic compound may be contained as long as it does not participate in the reaction. Specifically, xylene (o
- xylene, m- xylene, p- xylene, and mixtures thereof), 1,2,4 other trimethylbenzene, and mixtures thereof, C ₆ -C ₉ fraction produced during the further catalytic reforming,
Obtained from cracked gasoline produced by naphtha cracking
C ₆ -C ₉ fraction also can be a raw material.

Methanol and / or dimethyl ether or the like is used as the alkylating agent.

The present invention is usually carried out using a flow type fixed bed reactor, but it can also be carried out using a fluidized bed or a moving bed. The alkylation reaction is carried out under the following conditions. That is, the reaction temperature is about 150 to 600 ° C, preferably about 200 to 400 ° C.
Is. The reaction pressure is atmospheric pressure ~50kg / cm ² G, preferably atmospheric pressure ~30kg / cm ² G. Dialkylbenzene and /
Alternatively, the molar ratio of the alkylating agent to the aromatic compound containing trialkylbenzene is 0.2 to 20, preferably 0.5 to 10
Is. The above aromatic compound with an alkylating agent is generally 0.05～100Hr ^-1, fed to the reaction section preferably 0.1～30Hr ^-1 range weight units of hourly space velocity (WHSV).

WHSV is given by the following equation.

However, the raw material is the total amount of the aromatic compound containing dialkylbenzene and / or trialkylbenzene and the alkylating agent.

The raw material aromatic compound and the alkylating agent may be supplied to the reaction part individually or may be mixed in advance and supplied. Also,
It may be supplied after diluting it with a gas such as nitrogen, carbon dioxide, methane, or a saturated hydrocarbon that does not participate in the reaction.
Further, hydrogen is supplied to the reaction system for the purpose of maintaining the activity of the catalyst, and the supply amount thereof can be changed within a wide range depending on the reaction operating conditions. The molar ratio of hydrogen to the starting aromatic compound is in the range of 0.1 to 20, preferably 0.5 to 10.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Proton-type mordenite-type zeolite having a SiO ₂ ratio to Al ₂ O ₃ of 23, Na ₂ O, and 0.1% by weight (TSZ manufactured by Toyo Soda Kogyo Co., Ltd.
-640 type pellet type zeolite) (50 g) was added to 100 g of a 25% by weight aqueous solution of 12-tungstophosphoric acid, and the mixture was immersed at 50 ° C for 5 hours while gently stirring. As a result of measuring the concentration of 12-tungstophosphoric acid in the aqueous solution before and after immersion, 12-
The amount of tungstophosphoric acid supported on the zeolite was 18% by weight. The modified zeolite was dried at 110 ° C. for 8 hours and then calcined in an air stream at 610 ° C. for 5 hours. After pulverization, a range of 20 to 42 mesh was sieved to obtain a catalyst A.

Example 2 The mordenite-type zeolite used in Example 1 was calcined in an air stream at 520 ° C. for 5 hours. Next, the zeolite was pulverized and sieved in the range of 20 to 42 mesh, and 50 g of the sieve was subjected to modification treatment. Example 1 using 12-tungstosilicic acid
A denaturing treatment was performed under the same conditions as described above. The supported amount of 12-tungstosilicic acid was 14% by weight. The catalyst B was obtained by firing under the same conditions as in the example.

Example 3 Proton-type mordenite-type zeolite having a SiO ₂ ratio of 22 to Al ₂ O ₃ and 0.1% by weight of Na ₂ O (TSZ manufactured by Toyo Soda Kogyo Co., Ltd.
-640 type powdered zeolite) was calcined at 500 ° C for 3 hours. Next, an alumina sol aqueous solution was added as a binder so as to be 20% by weight with respect to the zeolite and kneaded, and then the water content was adjusted on a hot water bath. After compression molding, it was dried at 110 ° C. for 2 hours and then calcined in air at 520 ° C. for 16 hours. 50 g of the molded zeolite was immersed in 100 g of a 25% by weight aqueous solution of 12-molybdophosphoric acid for 16 hours at room temperature. The supported amount of 12-molybdophosphoric acid on zeolite is 20.
% By weight. After drying at 110 ° C. for 2 hours, it was baked at 610 ° C. for 5 hours in an air stream. 20 ~ 42 after crushing
The area of the mesh was sieved to obtain a catalyst C.

Comparative Examples 1 to 3 In Comparative Example 1, the conditions of Example 1 are used, and in Comparative Example 2, Example 2 is used.
In Comparative Example 3, zeolite was prepared under the conditions of Example 3 without modification with heteropolyacid, and Comparative Catalysts D, E and F were obtained.

Examples 4 to 6 and Comparative Examples 4 and 5 The reaction between xylene and methanol was carried out using a fixed bed atmospheric pressure flow reactor. Catalyst loading 5g, reaction temperature 30
0 ℃, the molar ratio of methanol to xylene is 2, WHSV
Was 5 hr ⁻¹ and the hydrogen flow rate was 100 ml / min. Using catalysts A, B and C and comparative catalysts D and E, the results after 4 hours from the start of the reaction are shown in Table 1.

The composition of xylene used as a raw material was as follows.

Non-aromatic compound 0.09 wt% Para-xylene 26.47 Meta-xylene 44.16 Ortho-xylene 25.41 Ethylbenzene 3.66 Others 0.20 Examples 7-9 and Comparative Examples 6 and 7 Using the same reaction apparatus as in Example 4, 1,2,4-trimethylbenzene was added. Reaction with methanol. Catalyst loading is 5
g, reaction temperature was 300 ° C., molar ratio of methanol to 1,2,4-trimethylbenzene was 2, WHSV was 5 hr ⁻¹ , and hydrogen flow rate was 100 ml / min. Table 2 shows the results 4 hours after the reaction was started using the catalysts A, B and C and the comparative catalysts D and F.

The purity of the raw material 1,2,4-trimethylbenzene was 99% by weight, the balance being C ₈ -C ₉ aromatics.

Example 10 Using the same reaction apparatus as in Example 4, 1,2,4-trimethylbenzene was reacted with methanol. Catalyst B for reaction
Using 5 g, the molar ratio of methanol to 1,2,4-trimethylbenzene is 2, the reaction temperature is 300 ° C., the WHSV is 5 hr ⁻¹ ,
The flow rate of hydrogen was 100 ml / min.

Table 3 shows the changes over time in conversion rates of 1,2,4 tetramethylbenzene.
It was like.

Comparative Example 8 Using Comparative Catalyst F, 1,2,4-trimethylbenzene was reacted with methanol under the same conditions as in Example 10.

The results are shown in Table 4.

[Effects of the Invention] As can be seen from Tables 1 to 4, according to the method of the present invention using a catalyst modified with a heteropolyacid and a heteropolyacid salt, the production of aromatic compounds having 11 or more carbon atoms is suppressed. Meanwhile, an aromatic compound containing a dialkylbenzene and / or a trialkylbenzene can be alkylated to produce a polyalkylbenzene. As a result, the yield of the target product can be improved from the reaction solution, and the separation and purification thereof can be facilitated. Further, as shown in Table 3, it can be seen that the catalyst according to the present invention shows stable conversion and selectivity even for a long oil passage time, and the activity is maintained for a long time.

As described above, the method for producing polyalkylbenzene according to the present invention is an industrially advantageous method capable of suppressing undesired side reactions and maintaining the catalyst activity for a long period of time.

Claims (4)

[Claims] 1. An aromatic compound containing a dialkylbenzene and / or a trialkylbenzene and an alkylating agent, in the presence of hydrogen, one or more selected from the group consisting of heteropolyacids and heteropolyacid salts. A method for producing polyalkylbenzene, which comprises reacting a crystalline aluminosilicate treated by contacting with a modifier containing a compound as a catalyst. 2. The method according to claim 1, wherein the alkylating agent is methanol and / or dimethyl ether. 3. The method according to claim 1, wherein the crystalline aluminosilicate is of the mordenite type. 4. The method according to claim 1, wherein the polyalkylbenzene is trimethylbenzene and tetramethylbenzene.