JPH07252170A - Production of ethylbenzene or p-xylene - Google Patents

Abstract

PURPOSE:To produce ethylbenzene or p-xylene which are extremely useful as chemicals in one step at a low cost by thermally reacting benzene using a zeolite as a catalyst. CONSTITUTION:Ethylbenzene or p-xylene can be produced by using benzene as the exclusive raw material to enable effective utilization of benzene discharged in large quantities in petroleum refinery by thermally reacting benzene at 150-700 deg.C (preferably 300-600 deg.C) under a pressure of 5-50 atm in a carrier gas (e.g. H.) using a catalyst produced by treating a zeolite with an organic silane compound of formula (R<1> to R<4> each is H or an alkoxy; R<1> to R<4> are not H at the same time). The zeolite catalyst is preferably an MFI-type zeolite having an Si/At ratio of 2-400 and synthesized by conventional process.

Description

Detailed Description of the Invention

[0001]

The present invention relates to ethylbenzene or p-
More particularly, it relates to a method for converting benzene into ethylbenzene or p-xylene using zeolite as a catalyst.

[0002]

2. Description of the Related Art Monocyclic aromatic compounds such as benzene, toluene and xylene occupy positions as main raw materials of various compound groups in the petrochemical industry, and it is considered that their position will not change significantly in the future. On the other hand, in the petroleum industry, from the viewpoint of environmental problems, the control problem of monocyclic aromatic compounds in gasoline has been particularly highlighted. As regulations on the concentration of benzene in gasoline become more serious in the future, it is expected that a large amount of benzene will be extracted in refineries of oil industry companies. As mentioned above, benzene is used in the petrochemical industry as styrene,
Although it is important as a raw material for basic chemical products such as phenol and maleic anhydride, it cannot be predicted that demand will increase so much in the future. Therefore, under such circumstances, it is desired to develop a new method of utilizing benzene.

As mentioned above, one of the major uses of benzene is the production of ethylbenzene as a raw material for styrene. This is usually carried out using an aluminum chloride / hydrochloric acid-hydrocarbon complex catalyst and is an industrially important technique. However, this production method requires ethylene as an alkylating agent, which has a great influence on the production cost, but it is technically completed, and there is little room for further technological development.

There is terephthalic acid, which is a raw material of polyethylene terephthalate, as a chemical product whose demand is expected to grow in the future. Although terephthalic acid is usually produced by oxidation of p-xylene, various production methods are conceivable for p-xylene as a raw material, and various studies are being made even now. For example, many techniques relating to the production of p-xylene by alkylation using toluene as a raw material and methanol have been disclosed. The problems of these methods are the utilization efficiency of methanol and the selectivity for p-xylene, and there is no technology that can withstand industrialization so far. Rather, a method for producing p-xylene by repeating isomerization and separation of xylenes is technically advanced and is also industrially performed. However, neither of these methods was a method using benzene as a raw material, which is expected to be a surplus in the future, and did not lead to effective use of benzene.

As a noteworthy technique, there is known a method of converting into a toluene, xylenes, naphthalene or methylnaphthalene compound only by passing benzene over a pentasil-type aluminosilicate (US Pat. No. 4,926,000). issue). This is a technology that can convert benzene without using an alkylating agent, and future development is expected as a technology for utilizing benzene. However, with this method, the selectivity of the reaction is low, and it is difficult as a production technology of p-xylene or ethylbenzene in terms of economy.

[0006]

Therefore, the present invention uses ethylbenzene and p- as a raw material more economically.
It is intended to provide a technique for producing xylene.

[0007]

Under such circumstances, the inventors of the present invention have conducted extensive studies and as a result, when benzene was heated and reacted using a zeolite treated with an organic silane compound as a catalyst, toluene, ethylbenzene and p- They found that xylene was produced, and completed the present invention.

That is, the present invention relates to a method for producing ethylbenzene or p-xylene by heating and reacting benzene with zeolite treated with an organosilane compound as a catalyst.

In the present invention, the organic silane compound refers to a compound in which a hydrogen atom of silane is replaced with an organic group, and specifically, for example, compounds represented by the following general formula are preferred.

[0010]

[Chemical 2]

(In the formula, R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an alkoxyl group which may be the same or different, provided that all of R ^{1 to} R ⁴ are hydrogen atoms at the same time. Nothing.)

The alkoxyl group represented by R ^{1 to} R ⁴ is preferably one having 1 to 6 carbon atoms, particularly methoxyl, ethoxyl or propoxyl.

The zeolite used in the present invention includes:
MFI-type zeolite (generally referred to as pentasil-type zeolite or ZSM-5 zeolite), Y-type zeolite (faujasite), mordenite, ferrierite, L-type zeolite, zeolite β, and the like, among which MFI-type zeolite, Y Type zeolite and mordenite
MFI type zeolite and mordenite are particularly preferable, and MFI type zeolite is preferable. MFI-type zeolite can be preferably used regardless of whether it has been synthesized by any production method, especially those described in JP-A-56-92114 (DGA zeolite) in terms of activity and selectivity. Are better. The optimum Si / Al ratio of zeolite varies depending on the type of zeolite, but the Si / Al ratio is usually 2
A range of up to 400 is preferred.

Zeolites are usually used in proton form (formed by ion-exchange of alkali metals in the zeolite framework lattice with ammonium ions or proton ions). The ion exchange rate can take any value, but the higher the exchange rate, the higher the activity. The conversion to the proton type foam can be performed before or after the organic silanization treatment.

In the present invention, it is also possible to use, as the zeolite, one containing at least one metal, metal ion and / or metal oxide by an ion exchange method or an impregnation method. Examples of such metal species are symbols of the CAS version of the periodic table, IB group, IIA group, IIB group, IIIA group, IIIB group, IV.
Group A, IVB, VB, VIB, VIIB and VIII metals are preferred. Specifically, Group IB metals include copper, silver and gold.
For Group IIA metals magnesium, calcium, strontium and barium, for Group IIB metals zinc and cadmium, for Group IIIA metals aluminum and gallium, II
Yttrium and all lanthanide series elements in Group IB metals, germanium, tin and lead in Group IVA metals, titanium, zirconium and hafnium in Group IVB metals, vanadium and niobium in Group VB metals, chromium in Group VIB metals. , Molybdenum and tungsten, manganese and rhenium for Group VIIB metals, and iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum for Group VIII metals are preferred.
Particularly preferred metal species are gallium, zinc, platinum, iron, copper and palladium. The metal-containing treatment of the zeolite can be performed before or after the organic silanization treatment.

The above MFI type zeolite, Y type zeolite,
Mordenite, when using a zeolite having an acid type such as zeolite β, it is preferable to treat the zeolite with an organic silane compound in a liquid phase, Na having no acid type
In the case of using zeolites of type K and type K, it is preferable to perform treatment with an organic silane compound and conversion to an acid type before use. In the latter case, the order of processing may be preceded by either one.

As the zeolite, in addition to the aluminosilicate zeolite in which the metal species in the skeleton is aluminum, metallosilicate zeolites such as iron, chromium, zinc, gallium, and boron, and alumino in which a part of aluminum is substituted with the above metal Metallosilicates can also be used.

The method of treating the zeolite with the organic silane compound is not particularly limited, and for example, a usual CVD method or a dipping method can be used.

The CVD method is a method in which an organic silane compound is passed over a crystalline aluminosilicate zeolite in an inert gas stream to deposit a part of the organic silane compound on the zeolite surface. Although this method is industrially difficult, it is excellent in that the zeolite surface can be uniformly coated.

In the dipping method, a predetermined amount of zeolite is immersed in a treatment liquid consisting of an organic silane compound alone or a solution obtained by diluting it with a non-aqueous solvent for a certain period of time, and then the zeolite is separated and calcined to deposit silica on the zeolite. This is the method of attachment. As the non-aqueous solvent, for example, in the case of a paraffinic solvent, n-
Hexane, n-heptane, cyclohexane and the like, and aromatic compounds include toluene, benzene and the like. The amount of the treatment liquid is not particularly limited as long as it can uniformly disperse the organosilane compound in the zeolite, but in general, it is preferably 0.1 to 10 times the weight of the zeolite. In general, it is preferable to use a solution having an organic silane concentration of 20% by weight or less.

The contact method between the zeolite and the organic silane compound in the dipping method is preferably a batch method, and the degree of silane treatment can be arbitrarily changed depending on the temperature, concentration and stirring conditions. Zeolite is usually treated with a treatment solution,
Although filtration is performed, this operation can be omitted when the throughput is small.

Zeolite is silanized and then calcined in an electric furnace in air to obtain a catalyst. The firing temperature is 600 ° C or lower, and particularly preferably 100 to 600 ° C. The firing time is preferably 2 hours or more, and particularly preferably 2 to 10 hours.

The benzene used in the present invention preferably has a high purity, but a few percent of impurities (toluene, etc.)
And any of those obtained by extraction for petroleum refining to those having reagent grade purity can be used.

The reaction system of the reaction according to the production method of the present invention is not particularly limited, and various methods such as a fixed bed flow system, a fluidized bed system, a moving bed system and a batch system can be carried out. The conditions in the fixed bed system will be explained below, but when the reaction is carried out by another system, it can be carried out under the conditions according to the conditions of the fixed bed system. Reaction temperature is 150-700 ℃, especially 300-600 ℃
Is preferred. The reaction pressure is preferably 1 to 100 atm, particularly preferably 5 to 50 atm. As the carrier gas, an inert gas such as nitrogen or hydrogen, carbon dioxide gas, methane gas or the like can be used. LHSV may be in the range of 0.1 to 10 h ^-1 . The carrier gas / raw material ratio can be selected from any value of 0.1 to 100 (mol / mol). Although the silane-treated zeolite exhibits a very stable activity, the activity is easily recovered by a normal activity-imparting method such as air calcination of the zeolite after the reaction to some extent.

[0025]

In the present invention, ethylbenzene and / or p, which are useful as chemical products, are directly selected from benzene with good selectivity.
-The reason why xylene is produced is not clear so far, but it is considered that the decomposition reaction of benzene occurs on the zeolite catalyst and the produced olefin compound is added to benzene as an alkylating agent to produce alkylbenzene. Conceivable. At this time, ethylbenzene and p-
It is presumed that the selectivity for xylene is increased because the silica adhering to the zeolite surface during the silanization treatment controls the fine diameter of the zeolite to a size that is advantageous for the production of ethylbenzene or p-xylene. In particular, it has been found that silane treatment of mordenite increases the activity of the benzene conversion reaction itself and further increases the stability of the catalytic activity.

[0026]

According to the method of the present invention, it is possible to economically produce ethylbenzene or p-xylene, which is very useful as a chemical product, in one step, using only benzene as a raw material. At the same time, this can contribute to the effective use of benzene, which is emitted in large quantities in the petroleum refining industry and is being regulated in full scale from the viewpoint of environmental protection. In the method of the present invention, ethylbenzene and p
-In addition to xylene, some by-products and some light gases (C1-C4) are produced as by-products, but since toluene is less toxic than benzene and has a higher octane number, it should be returned to gasoline as an octane booster for use. Therefore, the industrial significance of the present invention is extremely high.

[0027]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Synthesis Example 1 (1) Synthesis of zeolite (according to the synthesis method described in JP-A-56-92114) 1605 g of colloidal silica (silica content 20.6% by weight), 500 g of pure water and 362 g of diglycolamine. To the added solution,
A gel raw material was prepared by adding both an aqueous solution in which 30.6 g of caustic soda was dissolved in 500 g of pure water and an aqueous solution in which 31.6 g of sodium aluminate was dissolved in 493 g of pure water while stirring at a speed of 250 rpm. While heating, this was stirred in the same manner as gel aging. Then, in the autoclave, the temperature is 160 ℃
The mixture was heated and stirred again for 48 hours. The formed crystal product was filtered and then washed with pure water until the pH of the peraqueous solution became 8 or less to obtain a highly crystalline aluminosilicate zeolite. The obtained synthetic product was filtered, washed thoroughly with water, then, in an electric dryer, 110
Drying was carried out at ℃ for 3 hours.

(2) Conversion to Acid Type Zeolite Next, the above zeolite was subjected to ion exchange at 90 ° C. for 2 hours using a 4N ammonium chloride aqueous solution. The amount of the ammonium chloride aqueous solution used was 5 g per 1 g of zeolite, and this operation was repeated 3 times. After ion exchange, wash the zeolite until chlorine is no longer detected,
Further, it was dried in the same manner as above, and then calcined in the presence of air at 540 ° C. for 3 hours in an electric calcination furnace to obtain a proton-type zeolite.

Catalyst Production Example 1 (TEOS Method) 25 g of the proton-type zeolite obtained in Synthesis Example 1 was immersed in 50 g of a mixed solution of tetraethyl orthosilicate (TEOS) and toluene (TEOS concentration 1, 3 or 5% by weight). Then, after stirring for about 5 hours, it was taken out and placed in an electric furnace under air flow.
It was baked at 0 ° C. for 4 hours. Mold this into 32-64 mesh,
A silanized zeolite was obtained. Catalysts 1, 2 and 3 were designated in descending order of TEOS treatment concentration.

Catalyst Production Example 2 (TMOS Method) 25 g of the proton type zeolite obtained in Synthesis Example 1 was added to 50 g of a mixed solution of tetramethyl orthosilicate (TMOS) and toluene (TMOS concentration: 1, 3 or 5% by weight). Immerse, stir for about 5 hours, then take out and place in an electric furnace under air flow.
It was baked at 0 ° C. for 4 hours. Mold this into 32-64 mesh,
A silanized zeolite was obtained. Catalysts 4, 5 and 6 were used in order of increasing TMOS treatment concentration.

Catalyst Production Example 3 (CVD Method) 5 to 32 g of the proton-type zeolite obtained in Synthesis Example 1 was used.
It was molded into mesh and packed in a fixed-bed quartz glass reactor. Tetraethyl ortho metasilicate (TEOM)
Helium gas was blown into the glass reactor at a rate of 50 ml / min, and TEOM of vapor pressure was introduced into a glass reactor kept at a catalyst bed temperature of 300 ° C. After maintaining that state for 3 hours, the temperature of the catalyst bed was lowered to room temperature over 2 hours while purging the zeolite layer with only helium gas. Zeolite was taken out of the glass reactor and placed in an electric furnace under air flow 540.
Calcination was performed for 4 hours. This CVD-treated zeolite was used as catalyst 7.

Catalyst Production Example 4 (TEOS Method, Mordenite) Commercially available proton type mordenite (Tosoh Corp., HSZ-630H)
5g of OA, Si / Al = 16.1) was immersed in 10g of a mixed solution of TEOS and toluene (TEOS concentration 5% by weight), stirred for about 5 hours, then taken out and placed in an electric furnace under air flow at 540 ° C for 4 hours. Burned for hours. This was molded into 32 to 64 mesh to obtain a silanized zeolite. This TEOS-treated mordenite was used as catalyst 8
And

Catalyst Production Example 5 (TMOS Method, Metal Ion Exchange Zeolite) 10 g of the proton type zeolite obtained in Synthesis Example 1 was added to 0.1N.
Ion exchange was performed at 90 ° C. for 5 hours using 100 ml of an aqueous gallium nitrate solution. After ion exchange, the zeolite was washed and dried in an electric dryer at 110 ° C for 3 hours. Then, gallium ion-exchanged zeolite was obtained by calcination in an electric calcination furnace at 540 ° C. for 3 hours in the presence of air. As a result of measuring the gallium ion exchange rate of the above gallium ion exchanged zeolite using a plasma emission spectrophotometer (ICP), the gallium ion exchange rate in all the ion exchange sites was 71.1%. 10 g of this gallium ion-exchanged zeolite was immersed in 20 g of a mixed solution of TMOS and toluene (TMOS concentration 5% by weight), stirred for about 5 hours, then taken out, and fired in an electric furnace at 540 ° C for 4 hours under air flow. . This was molded into 32 to 64 mesh to obtain silanized gallium ion-exchanged zeolite. This was designated as catalyst 9.

Catalyst Production Example 6 (TMOS Method, Metal Ion Exchange Zeolite) 10 g of the proton type zeolite obtained in Synthesis Example 1 was added to 0.1N.
Ion exchange was performed for 5 hours at 90 ° C. using 100 ml of an aqueous solution of copper nitrate. After ion exchange, the zeolite was washed and dried in an electric dryer at 110 ° C for 3 hours. Then, in an electric calcination furnace, calcination was performed at 540 ° C. for 3 hours in the presence of air to obtain a copper ion-exchanged zeolite. As a result of measuring the copper ion exchange rate of the above copper ion exchange zeolite using a plasma emission spectrophotometer (ICP), the copper ion exchange rate in all the ion exchange sites was 83.1%. 10 g of this copper ion exchanged zeolite was immersed in 20 g of a mixed solution of TMOS and toluene (TMOS concentration 5% by weight), stirred for about 5 hours, and then taken out.
Firing was performed in an electric furnace at 540 ° C for 4 hours under air flow. This was molded into 32 to 64 mesh to obtain silanized copper ion-exchanged zeolite. This was designated as catalyst 10.

Catalyst Production Example 7 (TMOS Method, Metal Ion Exchange Zeolite) 10 g of the proton type zeolite obtained in Synthesis Example 1 was added to 0.1N.
Ion exchange was performed for 5 hours at 90 ° C. using 100 ml of an aqueous iron nitrate solution. After ion exchange, the zeolite was washed and dried in an electric dryer at 110 ° C for 3 hours. Then, in an electric calcination furnace, calcination was performed at 540 ° C. for 3 hours in the presence of air to obtain iron ion exchanged zeolite. As a result of measuring the iron ion exchange rate of the above iron ion exchanged zeolite using a plasma emission spectrophotometer (ICP), the iron ion exchange rate in all the ion exchange sites was 48.6%. 10 g of this iron ion-exchanged zeolite was immersed in 20 g of a mixed solution of TMOS and toluene (TMOS concentration 5% by weight), stirred for about 5 hours, and then taken out.
Firing was performed in an electric furnace at 540 ° C for 4 hours under air flow. This was molded into 32 to 64 mesh to obtain silanized iron ion exchanged zeolite. This was designated as catalyst 11.

Comparative Catalyst Production Example The proton type zeolite obtained in Synthesis Example 1 was used as Comparative Catalyst 1
And Further, the mordenite used in Catalyst Production Example 4 and the metal ion-exchanged zeolite prepared in Catalyst Production Examples 5 to 7 were molded into 32-64 mesh as they were, respectively, as Comparative Catalyst 2 (mordenite) and Comparative Catalyst 3 (gallium ion exchange). ), Comparative catalyst 4 (copper ion exchange) and comparative catalyst 5
(Iron ion exchange).

Test Example 1 Each of the catalysts obtained in Catalyst Production Examples 1 to 7 and Comparative Catalyst Production Example was evaluated. The reaction was carried out by a pressure fixed bed flow type reaction device using benzene of a reagent special grade manufactured by Kanto Chemical Co., Inc. as a raw material under the following conditions.

<Reaction conditions> Catalyst amount: 5 ml Reaction temperature: 500 ° C. Reaction pressure: 10 kg / cm ² G LHSV: 1.0 h ⁻¹ Hydrogen / benzene (mol / mol) Carrier gas: Hydrogen Carrier gas amount: 50 ml

<Analysis of reaction product> A sample of the reaction product for 3 to 4 hours after the start of the reaction was taken and analyzed by FID-gas chromatography (using PONA column manufactured by HP). The benzene conversion rate, ethylbenzene selectivity and p-xylene selectivity were determined according to the following formulas.

[0041]

[Equation 1]

(1) Evaluation of silanized MFI-type zeolite catalyst Table 1 shows the evaluation of Catalysts 1 to 7 in which DGA zeolite was silanized, together with the evaluation of Comparative Catalyst 1. From Table 1,
All of the silanized catalysts had a higher production ratio of ethylbenzene and p-xylene than the untreated comparative catalyst 1. By using the zeolite after the silanization treatment, the selectivity of ethylbenzene and p-xylene was obtained. It turns out to increase.

[0043]

[Table 1]

(2) Evaluation of Silanized Mordenite Catalyst The evaluation of the catalyst 8 obtained by silanizing mordenite is shown in Table 2 together with the evaluation of the comparative catalyst 2. As is clear from Table 2, the mordenite catalyst subjected to the silanization treatment has a higher benzene conversion rate and a higher ethylbenzene production rate than the untreated comparative catalyst 2.

[0045]

[Table 2]

(3) Evaluation of silanized metal ion-exchanged DGA zeolite catalysts Evaluations of catalysts 9 to 11 obtained by silanizing various metal ion-exchanged DGA zeolites are shown together with evaluations of comparative catalysts 3 to 5 3 shows. As is clear from Table 3, in any of the silanized catalysts, the production ratio of ethylbenzene and p-xylene was higher than that of the untreated comparative catalyst,
It can be seen that the selectivity of ethylbenzene and p-xylene is increased by using the zeolite after the silanization treatment.

[0047]

[Table 3]

Test Example 2 Table 4 shows the results obtained by reacting benzene under various conditions using the catalyst 1. Under either condition, ethylbenzene and p-
The selectivity of xylene is high.

[0049]

[Table 4]

Claims (3)

[Claims] 1. A method in which benzene is heated to react with zeolite treated with an organosilane compound as a catalyst,
A method for producing ethylbenzene or p-xylene. 2. The method according to claim 1, wherein the zeolite is a crystalline aluminosilicate zeolite. 3. An organosilane compound is represented by the following general formula (1): (In the formula, R ¹ , R ² , R ³ and R ⁴ each represent a hydrogen atom or an alkoxyl group which may be the same or different. However, not all of R ^{1 to} R ⁴ are hydrogen atoms at the same time. The manufacturing method of Claim 1 or 2 represented by these.