JP2550602B2 - Catalyst for transalkylation reaction - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transalkylation catalyst containing a modified saponite obtained by subjecting saponite to ion exchange with a metal element and then calcining.

(Prior Art) Layered clay minerals are minerals composed of silica, alumina, water, iron, alkaline earth metals, alkali metals, and the like, and have long been known as substances exhibiting solid acidity.

Smectite type layered clay minerals include Al, Mg, Li, Fe, Zn
Has a layered lattice structure composed of an octahedral layer coordinated with an oxide or hydroxide and a tetrahedral layer coordinated in the form of an oxide of Si and / or Al. It is known that the layer spacing can be arbitrarily changed by inserting various compounds, such as ions, complexes, organic or inorganic compounds, between two-dimensional layers of clay having a weak layered structure and having a weak binding force.

Clay containing montmorillonite as a main component, which is a typical smectite type layered clay mineral, is used for decolorizing aromatic compounds (benzene, toluene, xylene, etc.) and removing trace olefins in petrochemical processes. On the other hand, the layered clay mineral is expected to be used as a catalyst having shape selectivity, because the layered clay mineral has solid acidity, and the layer spacing can be arbitrarily changed by inserting various compounds between layers. However, many layered clay minerals release various molecules inserted between layers and interlayer water when heated, and the layer spacing may be contracted or the layered structure may be destroyed. Further, in the catalytic reaction at a higher temperature, the layered clay mineral often shrinks or is destroyed as described above, so that substantially only the outer surface can contribute to the reaction. Therefore, in order to effectively utilize the layered clay mineral as a solid acid catalyst, improvement by so-called cross-linking has been proposed to reinforce the layered clay mineral by forming "pillars" between layers. For example, in JP-A-59-139328, a reinforcing layered clay is prepared by reacting a smectite type clay with a polymer cationic pyridoxy inorganic metal complex, which is used as a catalyst in a conversion reaction of diisopropylbenzene to monoisopropylbenzene. Is disclosed. Further, Japanese Patent Laid-Open No. 163328/1984 also adopts a method of crosslinking with a cationic hydroxy metal complex when preparing a layered clay mineral catalyst. However, the formation of crosslinks is not always easy,
For example, in the preparation of a polynuclear hydroxide complex of aluminum, it takes a lot of time to prepare a catalyst such as aging of the complex and complicated operation.

(Problems to be Solved by the Invention) As described above, the conventional layered clay mineral catalyst cannot exhibit sufficient activity at high temperatures, and the crosslinking method for maintaining activity is not always easy. Therefore, it is an object of the present invention to provide a layered clay mineral that can sufficiently withstand high temperatures and that has high catalytic performance for transalkylation reaction.

(Means for Solving Problems) The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, ion-exchange the smectite-type layered clay mineral with a specific element and then calcining the solid acid. The present invention has been completed by finding out that there is a layered clay mineral that expresses, and further finding that the layered clay mineral has a transalkylation reaction activity.

That is, the present invention, saponite, Al, Zr, Ti, Fe
And a general formula obtained by ion-exchange with ions of one or more metal elements selected from Mg and then firing. (Wherein M ^{n +} is an ion of a metal element selected from the group consisting of Al, Zr, Ti, Fe and Mg, and n is an integer of 2 to 4) for a transalkylation reaction containing a modified saponite Regarding catalysts.

 The present invention will be described below.

In the present invention, First, the saponite is ion-exchanged. For ion exchange, Al, Zr, Ti, Fe and Mg
One or more metal elements selected from the above are used. These metal elements are used as compounds that generate ions in an aqueous solution such as inorganic acid salts such as nitrates, sulfates and phosphates and chlorides, or organic acid salts such as acetic acid and oxalic acid. Generally, it is easy to use an aqueous solution of nitrate or chloride. The concentration of the aqueous solution of the metal nitrate or chloride is not particularly limited, but usually it is preferably about 0.1 to 1 mol /. Ion exchange can be performed by immersing saponite in the metal ion aqueous solution thus prepared. Temperature for ion exchange is 0 to 90
C., preferably 10 to 70.degree. C. is suitable. still,
Ion exchange can be sufficiently performed even at room temperature. The time required for ion exchange is 1 to 50 hours, and 5 to 20 hours is usually sufficient. During ion exchange, it is preferable to gently stir in order to disperse saponite in the aqueous solution. After performing ion exchange for a predetermined time, the ion exchanged saponite is filtered and washed with water. Washing with water is preferably carried out until no metal ions are detected in the washing liquid.

The saponite ion-exchanged by the above method is dried and then fired. The firing temperature is 650 ° C or lower,
It is preferably 300 to 600 ° C. At a firing temperature of higher than 650 ° C, the specific surface area of the modified saponite obtained tends to decrease. The firing time is about 0.5 to 30 hours, preferably 1 to 10 hours. The firing can be carried out in an oxygen or air atmosphere or a nitrogen atmosphere.

The saponite used as a raw material for the modified saponite of the present invention can be not only the saponite itself but also a layered clay mineral containing saponite, particularly a smectite type layered clay mineral. As the smectite-type layered clay mineral, those containing, for example, montmorillonite, hectorite, laponite, bentonite, beidellite, nontronite, sauconite, etc. can be used in addition to saponite. There is no particular limitation on the content of saponite,
Usually 50% by weight, depending on the purpose of use, reaction conditions, etc.
The above is desirable. The smectite type layered clay mineral containing saponite may be a natural product or a synthetic product prepared by a hydrothermal synthesis method or the like.

As described above, the transalkylation catalyst containing the modified saponite of the present invention can be obtained.

The transalkylation reaction using the catalyst will be described below.

In the present invention, the transalkylation reaction includes, for example, a reaction in which monoalkylbenzene is obtained from dialkylbenzene and benzene. Examples of the alkyl group of dialkylbenzene and monoalkylbenzene include C1-6 lower alkyl groups such as ethyl, methyl, propyl, isopropyl, butyl, t-butyl, pentyl, isopentyl, and hexyl.

As the reaction system, a fixed bed or fluidized bed continuous flow reactor is suitable. The reaction pressure is usually atmospheric pressure to 100 kg / cm ² G, preferably atmospheric pressure to 50 kg / cm ² G. Reaction temperature is about 150 ~
The temperature is set to 500 ° C, preferably 200 to 450 ° C. The molar ratio of benzene to dialkylbenzene is 1 to 20, preferably 5 to 10. Weight unit hourly space velocity (WHSV)
Is 0.3 to 10 h ^-1 , preferably 0.5 to 5 h ^-1 . Further, it is preferable to supply, together with dialkylbenzene and benzene, gases such as nitrogen, argon, carbon dioxide, etc., which are inert to the reaction, as a carrier gas into the reaction system. It is also effective to make hydrogen coexist in the reaction system in order to maintain the activity of the catalyst resistant.

Although the present invention relates to a catalyst using a modified saponite made from saponite as a raw material, Other than F type saponite Both the OH type and saponite may exhibit catalytic activity for transalkylation reaction when treated in the same manner.

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

Example 1 0.2 mol of Al (NO ₃ ) ₃ / saponite in aqueous solution 1 24 g was dispersed, and ion exchange was performed at room temperature for 12 hours with gentle stirring. Ion-exchanged saponite is filtered off, washed with water until Al ³⁺ is no longer detected in the washing solution, and then Al ^{3 +} -exchanged saponite (hereinafter abbreviated as Al ³⁺ -S) is used.
It was dried at 0 ° C. for 12 hours. Then, it was fired at 400 ° C. for 4 hours in the presence of air using an electric furnace.

Next, the conversion reaction of diisopropylbenzene was carried out in the presence of calcined Al ³⁺ -S. A fixed bed flow reactor was used for the reaction, the reaction pressure was normal pressure, and the reaction temperature was
300 ℃, the molar ratio of benzene to m-diisopropylbenzene is 8.4, the weight unit hourly space velocity (WHSV) is 1.0h
^-1 was set. Also, nitrogen as a carrier gas is 400 ml / h
Was fed to the reactor at a flow rate of. Table 1 shows the average conversion rate of m-diisopropylbenzene and the selectivity of cumene for 1 hour after the start of the reaction.

Example 2 Al ³ ++ prepared and fired under the same conditions as in Example 1
Using S, the same apparatus as in Example 1 was used to carry out the conversion reaction of diisopropylbenzene. The conversion reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 250 ° C. Table 1 shows the conversion rate of m-diisopropylbenzene and the selectivity of cumene for 1 hour after starting the reaction.

Example 3 Al ³⁺ -S prepared under the same conditions as in Example 1 was fired at 600 ° C. for 4 hours using an electric furnace. Calcined Al ³⁺ -S
Was carried out under the same conditions as in Example 1 except that the reaction temperature was 400 ° C. The results are shown in Table 1.

Example 4 Al ³⁺ -S prepared under the same conditions as in Example 1 was fired at 300 ° C. for 4 hours in a nitrogen atmosphere. Al ³⁺ obtained by firing
The same reaction as in Example 1 was carried out using S. The reaction conditions are
The conditions were the same as in Example 1 except that WHSV was set to 0.62 h ^-1 . The results are shown in Table 1.

Comparative Example 1 Under the same conditions as in Example 1, instead of saponite, montmorillonite ^Was used for ion exchange (hereinafter abbreviated as Al ³⁺ -M). After firing under the same conditions as in Example 1, the same reaction conditions as in Example 1 were applied. The results are shown in Table 1. The conversion of m-diisopropylbenzene and the selectivity of cumene were low.

Comparative Example 2 6 mol of Al (NO ₃ ) ₃ 0.2 mol / water solution (500 ml) was stirred.
A 0.5 mol / aqueous solution of NaOH was slowly added dropwise at 0 ° C, and stirring and aging were carried out for 48 hours after completion of the addition to prepare a polynuclear hydroxide complex of Al. At room temperature, 12 g of montmorillonite was added to this solution and stirred for 24 hours to carry out ion exchange. After filtration, it was washed thoroughly with water and the ion-exchanged montmorillonite was dried at 110 ° C. for 12 hours. Then, it was fired in air at 400 ° C. for 4 hours using an electric furnace to obtain Al crosslinked montmorillonite (hereinafter abbreviated as Al-PM).

Using this Al-PM under the same reaction conditions as in Example 1, m-
The reaction of diisopropylbenzene and benzene was performed.
The results are shown in Table 1. The reaction using Al-PM was almost the same as the result of the method of the present invention, but it had a drawback that preparation of the layered clay mineral as a catalyst took a lot of time.

Example 5 24 g of the same saponite as used in Example 1 was dispersed in 0.2 mol / aqueous solution 1 of ZrO (NO ₃ ) ₂ and ion-exchanged by gently stirring at room temperature for 12 hours. The ion-exchanged saponite was filtered off, washed with water until Zr ⁴⁺ was not detected in the washing solution, and then dried at 110 ° C for 12 hours,
It baked at 400 degreeC using the electric furnace for 4 hours. Using the obtained ion-exchange saponite (hereinafter abbreviated as Zr ⁴⁺ —S), a conversion reaction of diisopropylbenzene was performed under the same conditions as in Example 1. The results are shown in Table 1.

Example 6 Saponite was ion-exchanged, washed with water, dried, and fired under the same conditions as in Example 1 except that 0.2 mol / aqueous solution of TiCl ₃ was used. The resulting Ti ⁴⁺ (TiCl ₃ is Ti ⁴⁺ in an aqueous solution
The conversion reaction of diisopropylbenzene was performed under the same conditions as in Example 1 using exchanged saponite (hereinafter, Ti ⁴⁺ —S). The results are shown in Table 1.

Example 7 Saponite was ion-exchanged under the same conditions as in Example 1 except that Fe (NO ₃ ) ₃ was used as the ion-exchange agent, followed by washing with water, drying and firing. Using the obtained Fe ³⁺ exchanged saponite (hereinafter Fe ³⁺ —S), a conversion reaction of diisopropylbenzene was performed under the same conditions as in Example 4. The results are shown in Table 1.

Example 8 Ion exchange of saponite was carried out under the same conditions as in Example 1 except that Mg (NO ₃ ) ₂ was used as the ion exchanger,
It was washed with water, dried, and baked. The conversion reaction of diisopropylbenzene was carried out under the same conditions as in Example 1 except that WHSV was 0.40 h ⁻¹ using the obtained Mg ²⁺ exchanged saponite (hereinafter Mg ²⁺ —S). The results are shown in Table 1.

Comparative Example 3 Proton type ZSM-5 having a molar ratio of SiO ₂ to Al ₂ O ₃ of 40
(Hereinafter abbreviated as HZSM-5) was calcined at 400 ° C. for 4 hours and subjected to a conversion reaction of diisopropylbenzene. The reaction conditions were the same as in Example 1. The results are shown in Table 1. The conversion of diisopropylbenzene and the selectivity of cumene were significantly inferior to those of Examples 1-8.

Example 9 Al ³⁺ -S used in Example 1 was subjected to the same reaction conditions as in Example 1 under the same reaction conditions as in Example 1 for 1 hour to 4 hours to 5 hours after the start of the reaction. And the cumene selectivity was measured. Table 2 shows the results.

Example 10 The reaction of Al ³⁺ -S used in Example 4 was continued for a long time under the same conditions as in Example 4, and the change in catalyst performance was examined by the same method as in Example 9. Table 2 shows the results.

Comparative Example 4 The reaction of Al ³⁺ -M used in Comparative Example 1 was continued under the same reaction conditions as in Comparative Example, and the change in catalyst performance was examined by the same method as in Example 9. Table 2 shows the results. Compared with the method of the present invention, the cumene conversion and the benzene selectivity were greatly reduced.

(Effects of the Invention) The catalyst for transalkylation reaction containing the modified saponite of the present invention is prepared because it is not necessary to form “pillars” in the layered clay mineral in the preparation, that is, to perform the operation of crosslinking, as in the known method. Easy to operate. Further, the catalyst containing the modified saponite of the present invention has a high conversion rate and selectivity in the transalkylation reaction, and has little deterioration in catalytic activity, although it is obtained only by ion exchange and calcination. .

Claims (4)

(57) [Claims] 1. A general formula obtained by ion-exchanging saponite with ions of one or more metal elements selected from Al, Zr, Ti, Fe and Mg, and then calcining. (In the formula, M ^{n +} is an ion of a metal element selected from the group consisting of Al, Zr, Ti, Fe and Mg, and n is an integer of 2 to 4) Reaction catalyst. 2. The catalyst according to claim 1, wherein the transalkylation reaction is a reaction for obtaining a monoalkylbenzene from a dialkylbenzene and benzene. 3. The catalyst according to claim 2, wherein the dialkylbenzene is diisopropylbenzene and the monoalkylbenzene is monoisopropylbenzene. 4. The catalyst according to claim 1, which is calcined at 650 ° C. or lower.