JPH11309375A - Production of solid acid catalyst and isomerization of saturated hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solid superacid catalyst exhibiting high activity and selectivity sufficient for the isomerization of saturated hydrocarbons and stably keeping the high performances for a long term, and to provide a production method, therefor and an isomerizing method for saturated hydrocarbons by using this catalyst. SOLUTION: This solid superacid catalyst isomerizes the skeleton of a saturated hydrocarbon and which is represented by MO/SO4 <2-> /M'O2 (wherein, M is a group IIb metal such as Zn; and M' is a group IV metal such as Zr). The production method of the catalyst comprises the steps of carrying sulfuric acid or a sulfate radical-containing compound on M'(OH)4 , carrying MCl2 , M(NO3 )2 or the like on M'(OH)4 , and burning it. The isomerizing method carries out the isomerization of a 4-8C saturated hydrocarbon (for instance, from n-butane to i-butane) in the presence of the above catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a solid acid catalyst and a method for isomerizing a saturated hydrocarbon, and more particularly, to a method for skeletal isomerization of a saturated hydrocarbon having 4 to 8 carbon atoms. The present invention relates to a solid acid catalyst used for isomerization and a method for producing the same.

[0002]

2. Description of the Related Art At present, gasoline for automobiles contains aromatic compounds and olefins as octane improvers. Recently, however, attention has been paid to environmental protection. For this purpose, it is desired to use alkylates or oxygen-containing compounds, for example, MTBE. Branched saturated hydrocarbons such as isobutane useful for producing alkylates and oxygenates are generally produced by skeletal isomerization of the corresponding linear saturated hydrocarbons (n-alkanes). .

[0003] Such skeletal isomerization is an industrially important technique, and a large number of studies have been made mainly on catalysts used for the isomerization. In a typical one,
Friedel-Craft type catalyst (AlCl ₃ + HCl
), Bifunctional catalyst (MoO ₃ / Al ₂ O ₃ system, Pt
/ Al ₂ O ₃ system, Pt / zeolite system, etc.) are known. However, since these catalysts need to use chlorine compounds, they have problems such as corrosion of equipment and safety of operation, and further, side reactions such as cleavage of carbon-carbon bond and dehydrogenation occur. There is a problem that the selectivity of the target product is insufficient, and in the case of a bifunctional catalyst, platinum is required in many cases, resulting in an increase in cost.

On the other hand, a solid superacid catalyst has been known as a catalyst having a high n-alkane skeletal isomerization ability under relatively mild conditions even in the absence of chlorine compounds (Japanese Patent Application Laid-Open No. 61-1986). No. 68137, JP-A-61-68138
JP, JP-A-61-263932, JP-A-61-263932
-280440, JP-A-5-200296, JP-A-6-210176, etc.). All of these conventional solid superacid catalysts have the following formula: X / SO ₄ ²⁻ / Y
Or SO ₄ ²⁻ / Y, where X represents a Group VIII metal, especially platinum (Pt), and Y represents a Group III or Group IV oxide. However, none of these solid superacid catalysts still have sufficient activity (conversion) and selectivity, and have relatively short lifetimes.
In addition, many of them require platinum, which is costly, and a new catalyst system to replace them has been demanded.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and has a sufficiently high activity and selectivity in the isomerization of a saturated hydrocarbon, and has a long-term stable activity. An object of the present invention is to provide a solid superacid catalyst to be retained, a method for producing the same, and a method for isomerizing a saturated hydrocarbon using the catalyst.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the use of a solid superacid catalyst system having a specific structure obtained by a reaction between a specific metal compound and a sulfate group-containing compound has led to the problems described above. Have been found, and the present invention has been completed.

[0007] That is, the present invention comprises a support comprising a hydroxide or an oxide of a Group IV metal containing a Group IIb metal or a compound thereof and a compound containing a sulfate group or a precursor of a sulfate group, followed by firing. And a solid acid catalyst for skeletal isomerization of a saturated hydrocarbon. The present invention also provides the following formula: MO / SO ₄ ²⁻ / M′O ₂ , wherein M represents a Group IIb metal and M ′ represents a Group IV metal.
A solid acid catalyst for skeletal isomerization of a saturated hydrocarbon, characterized by being represented by Further, the present invention relates to IV
A hydroxide or oxide of a group metal, treated simultaneously with a) a group IIb metal or a compound thereof, and b) a compound containing a sulfate group or a precursor of a sulfate group, or sequentially with (a treated with b and then treated with b) Or after treating with b and then treating with a)), and then stabilizing the calcined product. The present invention also relates to a method for isomerizing a saturated hydrocarbon, which comprises isomerizing a saturated hydrocarbon having 4 to 8 carbon atoms in the presence of the solid acid catalyst of the present invention.

In the present invention, the group IV metal is defined as Periodic Table I
Group V metal, titanium (Ti), zirconium (Zr) or hafnium (Hf) group IVb metal, silicon (S
i), a group IVa metal of germanium (Ge), tin (Sn) or lead (Pb). The group IIb metal is a metal belonging to group IIb of the periodic table, and is zinc (Zn), cadmium (Cd), or mercury (Hg). Examples of the compound of Group IIb metal include chlorides, nitrates, carbonates, oxalates, and hydroxides. Further, compounds containing a sulfate group include sulfuric acid (H ₂ SO ₄ ), ammonium sulfate [(NH ₄ ) ₂ SO ₄ ], ammonium hydrogen sulfate [(NH ₄ ) HSO ₄ ], etc. Means ammonium sulfite [(NH ₄ ) ₂ S
O ₃ ] and sulfuryl chloride (SO ₂ Cl ₂ ). Sulfuric acid, ammonium sulfate, and the like are preferable as the compound that provides these sulfate groups.

The solid acid catalyst of the present invention has the following formula: MO / SO ₄ ²⁻ / M′O ₂ , wherein M represents a Group IIb metal and M ′ represents a Group IV metal, as described above. ). The amount of MO to be supported is 0.01 to 20% by weight, preferably 0.05 to 10% by weight, particularly preferably 0.1 to 5% by weight. This is because if the content is less than 0.01% by weight, the effect of the supported metal is low, and the selectivity as the catalytic activity is poor. If it exceeds 20% by weight, the acidity is reduced and the conversion is reduced. The compound containing sulfuric acid or the precursor of the sulfate group is 0.01 to 10 N, preferably 0.1 to 5 N in the case of sulfuric acid, and 0.01 to 1 N in the case of another substance.
By using a catalyst having a molar concentration of 0, preferably 0.1 to 5 molar, 1 to 20 times the weight of the catalyst, the catalyst targeted by the present invention can be obtained. The method of causing the carrier to contain the supported metal and sulfate is not particularly limited,
For example, a carrier may be impregnated with a carrier-containing solution or a sulfate-containing compound-containing solution having a predetermined concentration and a predetermined volume, or may be allowed to flow down. As described above, the order in which the supported metal and the sulfate group are contained is not limited, and the liquid containing both may be impregnated or flowed down.

The saturated hydrocarbon to be skeletally isomerized using the solid acid catalyst of the present invention has 4 to 8 carbon atoms, specifically, butane, pentane, hexane, heptane or octane. These saturated hydrocarbons are obtained by using the solid acid catalyst of the present invention to form a linear one into a branched one, or a branched one into a straight one, or another branched one having the same number of carbon atoms. Can be isomerized to

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The solid acid catalyst of the present invention is obtained by treating a support comprising a hydroxide or an oxide of a Group IV metal with a Group IIb metal or a compound thereof and a compound containing a sulfate or a precursor of a sulfate. After loading the metal component and the sulfate group component on the carrier,
° C, preferably 0.5 to 12 at a temperature of 550 to 750 ° C.
It can be produced by stabilizing the calcination for a period of time, preferably 1 to 5 hours. The solid acid catalyst thus produced has a reaction activity of isomerizing to a corresponding skeletal isomer by contacting a saturated hydrocarbon having 4 to 8 carbon atoms under the reaction conditions. Suitable reaction conditions for the skeletal isomerization reaction using the catalyst of the present invention depend on the raw materials and the reaction scheme. In addition, the reaction can be performed in both the gas phase and the liquid phase. The reaction temperature is suitably from 0 ° C to 400 ° C, preferably from room temperature to 250 ° C. Reaction pressure is 1-100
kgf / cm ² is suitable. Although it is not essential to add hydrogen gas to the reaction system, it is preferable to add hydrogen gas in order to maintain the performance of the catalyst for a long period of time. For example, a H ₂ : saturated hydrocarbon volume ratio of 1: 1 to 5 is preferable. : It is appropriate that hydrogen gas is added to about 1: 1.

[0012]

Next, an embodiment of the present invention will be described.
The present invention is not limited to these.

[0013] Example 1 zirconium oxychloride octahydrate (ZrOCl ₂ · 8H
The ₂ O) 500 g was dissolved in pure water 5L, stirring 28
% Ammonia water is added dropwise about 200 mL,
H is set to 8, and the resulting zirconium hydroxide [Zr (O
H) ₄ ] was aged at room temperature for 2 days. The resulting white precipitate was filtered, washed with water at 70 to 80 ° C until the filtrate became neutral, and then dried at 60 to 110 ° C for 2 days.
30 g of generated zirconium hydroxide [Zr (OH) ₄ ]
Was impregnated with 500 mL of 1N sulfuric acid at room temperature for 1 hour, filtered, and dried at 115 ° C. for 5 hours to obtain sulfuric acid-supported zirconium hydroxide. Then, zinc chloride (Z
0.6 g of nCl ₂ ) was dissolved in a small amount of pure water, impregnated with 30 g of sulfuric acid-supported zirconium hydroxide obtained in the previous step, evaporated to dryness, and dried at 115 ° C. for 5 hours. The dried product was calcined at 600 ° C. for 3 hours in the air to obtain a 1% by weight ZnO / SO ₄ ²⁻ / ZrO ₂ catalyst which is a zinc-supported sulfate activated solid superacid catalyst. The specific surface area of this catalyst was 113.6 m ² / g.

Examples 2 to 5 In place of 1% by weight of ZnO supported in Example 1,
0.1% (Example 2), 0.5% (Example 3), 2.0% (Example 4) and 5.0% by weight
When the products of Example 5 were prepared, their specific surface areas were as shown in Table 1.

[Table 1] ZnO loading (% by weight) Specific surface area (m ² / g) ─────────────────────────────── Example 2 0.1 110.4 Example 3 0.5 115.8 Implementation Example 4 2.0 98.2 Example 5 5.0 49.7

Example 6 In place of zinc chloride in Example 1, zinc nitrate 0.83
except for using the g by following the procedure of Example 1, to obtain a 1 ^{_{wt% ZnO / SO 4 2- / ZrO}} 2 catalyst. Example 7 Instead of zinc chloride in Example 1, zinc carbonate 0.82
except for using the g by following the procedure of Example 1, to obtain a 1 ^{_{wt% ZnO / SO 4 2- / ZrO}} 2 catalyst. Example 8 In place of zinc chloride in Example 1, zinc oxalate was added.
The same operation as in Example 1 was performed except that 68 g was used, and 1
A weight% ZnO / SO ₄ ²⁻ / ZrO ₂ catalyst was obtained. Example 9 Instead of zinc chloride in Example 1, zinc hydroxide 0.4
The same operation as in Example 1 was performed except that 4 g was used, to obtain a 1% by weight ZnO / SO ₄ ²⁻ / ZrO ₂ catalyst.

Example 10 The same operation as in Example 1 was carried out except that 500 mL of 1 mol / L ammonium sulfate was used in place of sulfuric acid in Example 1, and a 1 wt% ZnO / SO ₄ ²⁻ / ZrO ₂ catalyst was prepared. Obtained.

Test Example 1 In a flow-through reactor, the catalyst obtained in Example 1 was used.
After pretreatment in helium at 250 ° C. for 3 hours, n-butane isomerization was performed under the following reaction conditions (WHSV is a space velocity per hour in a gas phase reaction in the following reaction conditions). . Reaction conditions: Temperature: 200 ° C. Total pressure: 1 kgf / cm ² WHSV: 0.5 h ⁻¹ Linear velocity: 300 m / h H ₂ / n-butane: 3 (v / v) For comparison, a conventional catalyst was used. SO ₄ ^2- / Zr
O ₂ catalyst (Comparative Example 1) and 1.0 wt% Pt / SO ₄
^{Using the 2-} / ZrO ₂ catalyst (Comparative Example 2), the same isomerization reaction of n-butane was performed under the same reaction conditions as above. FID-GC was used for analysis of raw materials and products. The results of the above tests are summarized in Table 2 below, and Table 3 summarizes the specific surface areas of the three catalyst systems and the amount of acid by ammonia TPD.

[0018]

[Table 2] Catalyst system n-butane conversion isobutane selectivity isobutane yield (% By weight) (% by weight) (% by weight) << Example 1 56. 4 88.6 50.0 Comparative Example 1 31.4 89.9 28.2 Comparative Example 2 59.7 77.0 46.0} ──────────────

[0019]

[Table 3] Catalyst system Specific surface area (m ² / g) Acid amount (μmol / g) {Example 1 113.6 293 Comparative Example 1 130.0 263 Comparative Example 2 127.5 251} ───────────────────────────

As shown above, the order of the n-butane conversion and the isobutane selectivity are respectively shown in Comparative Example 2> Example 1>.
Comparative Example 1 and Comparative Example 1> Example 1> Comparative Example 2. However, the yield of isobutane represented by the product of the conversion and the selectivity, which is the most important for the isomerization reaction, was 5% in Example 1.
0.02 wt%, which was significantly higher than 28.2 wt% in Comparative Example 1 and 46.0 wt% in Comparative Example 2. This difference indicates that the catalyst of the present invention is very useful industrially. Further, the catalyst of Example 1 of the present invention is
It is also evident that it has a high acid content while having a specific surface area comparable to that of the species of catalyst (see Table 3).

Test Example 2 Using the catalyst of the present invention obtained in Example 1, an isomerization reaction of n-butane was carried out under the reaction conditions shown in Test Example 1 to obtain n-butane.
The changes over time in the butane conversion and the isobutane selectivity were examined. The results are shown in FIG. 1, which shows that the initial activity and selectivity are maintained even after about 1700 hours from the start of the reaction.

Test Example 3 Using the catalysts of the present invention obtained in Examples 1 to 5, n-butane isomerization was carried out under the reaction conditions shown in Test Example 1.
The effect of metal loading on n-butane conversion and isobutane selectivity was investigated. The results are shown in FIG.
It can be seen that the supported metal amount in the vicinity shows the highest isobutane yield (n-butane conversion rate x isobutane selectivity).

Test Example 4 The calcination temperature of the catalyst in Example 1 was 600 ° C., but this was changed to 500 ° C., 550 ° C., 650 ° C., 700 ° C.
The solid acid catalysts were obtained in place of 750 ° C. or 800 ° C., and they were subjected to n-butane isomerization reaction under the reaction conditions shown in Test Example 1, and the effect of calcination temperature on n-butane conversion and isobutane selectivity. Was examined. The results are shown in FIG. 3, which shows that the catalyst obtained at a calcination temperature around 600 ° C. shows the highest isobutane yield.

Test Example 5 The same test as in Test Example 1 was carried out by changing the WHSV, the linear velocity or the H ₂ / n-butane ratio among the reaction conditions in Test Example 1 in various ways. The results are shown in FIGS. From these results, the WHSV showed the highest isobutane yield near 0.5 h ^-1 , and the linear velocity and the H ₂ / n-butane ratio were almost the same in all the measured ranges. It can be seen that

Test Example 6 As shown in Test Example 2, the catalyst produced in Example 1 maintains its activity for a long period of time. After regenerating by firing, the activity was examined according to the method of Test Example 1. The results are shown in FIG. 7, which shows that the initial activity and selectivity were maintained throughout the test period of 100 hours. This proved that the catalyst of the present invention had an extremely long life and did not lose its activity even when regenerated.

[0026]

As described in detail above, the solid acid catalyst of the present invention does not require the presence of a chlorine compound,
It exhibits high saturated hydrocarbon isomerization ability under mild conditions, has very high isomerization activity and selectivity, and maintains its high performance stably for a long period of time. Further, the catalyst of the present invention does not require an expensive metal component such as platinum, so that not only the cost is low, but also the activity is not lost by regeneration, so that the catalyst can be repeatedly used, and the saturated carbonization can be performed at lower cost. Hydrogen isomerization can be performed. Also,
The solid acid catalyst of the present invention can be produced very easily without any difficult operation. Furthermore, by using the solid acid catalyst of the present invention, the isomerization reaction of a saturated hydrocarbon can obtain a desired isomerized product in a higher yield. Therefore, the isomerization reaction of the present invention provides an isoparaffin, for example, isobutane, which is useful as an octane improver or as an alkylating agent in a higher yield, and is industrially extremely useful.

[Brief description of the drawings]

FIG. 1 is a graph showing changes over time in conversion and selectivity of the solid acid catalyst of the present invention.

FIG. 2 is a graph showing the effect of the amount of supported metal on the conversion and selectivity in various solid acid catalysts of the present invention.

FIG. 3 is a graph showing the effect of the calcination temperature on the conversion and selectivity when producing the solid acid catalyst of the present invention.

FIG. 4 is a graph showing the effect of reaction conditions (WHSV) on the conversion and selectivity of the solid acid catalyst of the present invention.

FIG. 5 is a graph showing the effect of reaction conditions (linear velocity) on the conversion and selectivity of the solid acid catalyst of the present invention.

FIG. 6 is a graph showing the effect of reaction conditions (H ₂ / n-butane ratio) on the conversion and selectivity of the solid acid catalyst of the present invention.

FIG. 7 is a graph showing changes over time in conversion and selectivity after regenerating the solid acid catalyst of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuki Kiso 6-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside General Research Laboratory of General Petroleum Co., Ltd. (72) Inventor Kazuyoshi Igarashi Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 6-1 General Research Institute of Petroleum Co., Ltd.

Claims (4)

[Claims] 1. A carrier comprising a hydroxide or oxide of a Group IV metal, containing a Group IIb metal or a compound thereof and a compound containing a sulfate group or a precursor of a sulfate group, and calcining the mixture. A solid acid catalyst for skeletal isomerization of a saturated hydrocarbon. 2. A compound represented by the following formula: MO / SO ₄ ²⁻ / M′O ₂ (where M represents a Group IIb metal and M ′ represents a Group IV metal). Solid acid catalyst for skeletal isomerization of saturated hydrocarbons. 3. A hydroxide or oxide of a Group IV metal, treated simultaneously with a) a Group IIb metal or a compound thereof, and b) a compound containing a sulfate group or a precursor of a sulfate group, or sequentially, followed by calcination. A method for producing a solid acid catalyst for skeletal isomerization of a saturated hydrocarbon, characterized by comprising stabilizing. 4. A method for isomerizing a saturated hydrocarbon, which comprises isomerizing a saturated hydrocarbon having 4 to 8 carbon atoms in the presence of the solid acid catalyst according to claim 1 or 2.