JPS5940506B2 - Catalyst for dimerization of α-olefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst for dimerization or co-dimerization of α-olefins.

More specifically, the present invention relates to a catalyst that is highly active in the dimerization or co-dimerization reaction of α-olefins and that can be used for a long period of time without any decrease in activity.
Dimers or codimers of α-olefins, typified by 4-methyl-1-benzene, are used as monomers for producing polyolefins.

Many basic catalysts have heretofore been proposed as catalysts for producing corresponding dimers or codimers by dimerization or codimerization reactions of α-olefins.

However, most of these catalysts have drawbacks such as low activity, insufficient selectivity toward the desired product, or short catalyst life even if the initial activity is high, and they cannot be used on an industrial scale. There are few methods that can be effectively used in implementation. Among these basic catalysts that have been proposed in the past, catalysts in which sodium metal is dispersed in a granular anhydrous potassium compound are disclosed in Japanese Patent Publication No. 42-22474, Japanese Patent Publication No. 43-25344, and Japanese Patent Application Laid-Open No. It is disclosed in Japanese Patent Application Laid-Open No. 55-145533 and Japanese Patent Application Laid-Open No. 1983-145534. In particular, among these proposals, the
Publication No. 474 shows an example in which granular potassium carbonate containing a small amount of graphite is used as a granular anhydrous potassium compound as a carrier, but all of these catalysts have poor catalytic activity and selectivity to the desired product. It is also advantageous in terms of ease of preparation and handling during industrialization, but since the catalyst activity decreases in a relatively short period of time, the catalyst must be replaced frequently. Furthermore, among the basic catalysts that have been proposed in the past, catalysts in which an alkali metal is supported on a type of carrier other than the above-mentioned anhydrous potassium compound have been proposed. For example, attempts have been made to use a catalyst in which an alkali metal is supported on a carbon carrier such as graphite as a dimerization catalyst for α-olefin.
No. 2,822, No. 912,823, No. 932,342
However, similar to the above, these catalysts do not have sufficiently high catalytic activity, catalyst life, or selectivity to the target dimerization product, and cannot be used on an industrial scale. It has not been. Therefore, in any case, it is a challenge to improve the catalytic activity and extend the active life of a catalyst in which an alkali metal is supported on a carrier. Similarly, in the method using catalytic converters, the biggest challenge is to improve the catalytic activity and to suppress the decrease in the activity. The present invention was made in view of the above-mentioned current situation, and its object is to provide a catalyst for dimerization or co-dimerization of α-olefins that is highly active, highly selective to the target product, and has a long life. Our goal is to provide the following.

The present invention is based on the discovery that the above object can be achieved by using a catalyst in which an alkali metal of a specific composition is supported on a compression-molded granular carrier made of carbon and anhydrous potassium carbonate having specific properties. To summarize the present invention, the present invention provides a catalyst in which an alkali metal prisoner is supported on a carrier mainly composed of anhydrous potassium carbonate (
1) The alkali metal prison consists of a mixture of sodium metal (a) and potassium metal (b), the composition of which is in the range of 20 to 90 g at % of sodium metal (a) and 10 to 80 g at % of potassium metal (b). (4) The carrier(s) is charcoal. c) and anhydrous potassium carbonate (d), and the content of the carbon (c) (c) is in the range of 0.6 to 3% by weight based on the anhydrous potassium carbonate (d). (110) The anhydrous potassium carbonate constituting the carrier 8 has an average particle size of the raw powder before compression molding of 150 to 6.
00μ range, and powder with a particle size of less than 100μ is 1
to 15% by weight, and the powder having a particle size exceeding 600μ is anhydrous potassium carbonate having a particle size distribution in the range of 1 to 20% by weight, and 0) the pore volume ratio of the carrier field is 22% by weight. and the compressive strength is in the range of 1.5 to 15k9/(177
! -G is a catalyst for dimerization of α-olefin.

Alkali metal (4) which is one of the constituent components of the catalyst of the present invention
consists of a mixture of sodium metal (a) and potassium metal (b), and its composition is 20
and potassium metal (b) in the range from 90 g at %
It should be in the range of 10 to 80 gram at%.

The composition ratio of sodium metal among the alkali metals is 90
When the composition ratio of potassium metal is greater than 10 gram at % and less than 10 gram at %, the catalyst activity and selectivity to dimerization products decrease, and in particular, the induction period until the highest activity is exhibited becomes significant. become longer. In addition, the composition ratio of sodium metal becomes less than 20 g at%,
If the composition ratio of potassium metal is greater than 80 gram at %, the initial activity of the catalyst will be high, but the activity will be significantly reduced and the life of the catalyst will be shortened. Furthermore, the composition of the alkali metal mixture is in the range of 30 to 85 g at % of sodium metal (a) and 15 to 70 g at % of potassium metal (b).
It is preferable that the amount is in the range of gram atom % because a catalyst with excellent catalytic activity, catalyst life, and selectivity to the desired dimerization product can be obtained. If necessary, other components may be added to this alkali metal mixture to form a supporting component. Further, the proportion of the alkali metal mixture in the supported components on the carrier is usually 0.5 to 10% by weight, preferably 1 to 5% by weight based on the anhydrous potassium carbonate (d) as a component of carrier 8. % range.

The carrier, which is another component of the catalyst of the present invention, is a carrier mainly composed of anhydrous potassium carbonate, and more specifically, compression-molded granules composed of carbon (c) and anhydrous potassium carbonate (d). It is a lying carrier. The carbon (
The content of O is 0.0% relative to the anhydrous potassium carbonate (d).
It is necessary that the content be in the range of 6 to 3% by weight. When the content of carbon (c) in the carrier is less than 0.6% by weight, the catalyst activity, catalyst life and selectivity to the desired α-olefin dimerization product will decrease.
The bulk density of the anhydrous potassium carbonate constituting the compression molded granular carrier 8 before compression molding is usually 1.09/RILl or less, and the anhydrous carbonate having a bulk density in the range of 0.9 to 0.5 g/ml The use of potassium as a component of the compacted granulated support is preferred as it improves catalyst activity, catalyst life and selectivity to dimerization products. Also, the carbon (c)
Even if the content of is greater than 3% by weight, both the catalyst activity and the selectivity to the desired dimerization product no longer improve, and when compression molding, the compressive strength decreases to 1. 5k9/CT! ! -G or higher becomes difficult to obtain, and catalysts prepared from this support have a short lifespan and cannot be used on an industrial scale. In order to obtain a catalyst with a long catalyst life and high selectivity to the desired dimerization product, the content of carbon (c) should be 0.8 to 2% by weight based on anhydrous potassium carbonate (d). Preferably within this range. The carrier, which is a component of the catalyst of the present invention, is a compression-molded granular carrier containing anhydrous potassium carbonate as a main component. It is a shaped granular carrier.

The raw powder of the anhydrous potassium carbonate constituting this compression-molded granule carrier leaf before compression molding has an average particle size of 150 to 600.
Anhydrous potassium carbonate having a particle size distribution in which the powder with a particle size of less than 100μ is in the range of 1 to 15% by weight, and the powder with a particle size of more than 600μ is in the range of 1 to 20% by weight. It is necessary that there be. Further, the average particle size is in the range of 200 to 600μ, and the particle size is 10
Compression-molded granules obtained from anhydrous potassium carbonate raw powder having a particle size distribution in which the powder with a particle size of less than 0μ is in the range of 2 to 10% by weight and the powder with a particle size of more than 600μ is in the range of 2 to 15% by weight. Catalysts prepared from supports are preferred because of their improved catalytic activity, catalyst lifetime, and selectivity to dimerization products. Anhydrous potassium carbonate raw powder with a narrow particle size distribution, for example, average particle size of ordinary commercially available anhydrous potassium carbonate 3350
The powder in the range of 800μ to 800μ has a composition of powder with a particle size of less than 10100μ and a composition of powder with a particle size of more than 600μ, both of which are less than 1% by weight, and the compressed powder obtained from this anhydrous potassium carbonate raw powder Catalysts prepared from shaped supports suffer from reduced catalytic activity, catalyst lifetime and selectivity towards dimerization products. Note that the specific anhydrous potassium carbonate used in the method of the present invention can be prepared by various methods. For example, conventionally known methods include mixing anhydrous potassium carbonate powder with a narrow particle size distribution with anhydrous potassium carbonate powder having a different distribution to achieve the aforementioned particle size distribution. be able to. Further, the carrier constituting the catalyst of the present invention needs to be a compression-molded carrier consisting of the carbon (c) and the anhydrous potassium carbonate (d) and having a specific property. More specifically, the compression-molded granular carrier film needs to have a pore volume ratio in the range of 22 to 38% and a compression strength in the range of 1.5 to 15 kg/~-G. It is. There is a correlation between this pore volume ratio and compressive strength, and outside the above numerical range, when the pore volume ratio of the compression-molded granular carrier (g) increases and the compressive strength decreases, the catalyst The initial activity tends to be high to a certain extent, which tends to cause a decrease in activity and shorten the catalyst life.Also, since the strength of the prepared catalyst is insufficient, it crumbles and becomes powder during use, further shortening the catalyst life. Therefore, it cannot be used on an industrial scale. Furthermore, when the pore volume ratio of the compression-molded carrier field becomes smaller and the compressive strength becomes larger, the catalyst activity becomes lower and the selectivity to the desired dimerization product decreases. Excellent catalyst activity, catalyst life and selectivity to dimerization products,
Moreover, in order to obtain a catalyst suitable for use in industrial-scale reactions, the compression-molded granular carrier film should have a pore volume ratio in the range of 26 to 33% and a compressive strength of 2 to 10k9/ It is preferably in the range of d-G. Specifically, carbon (c) which is a component of the compression-molded granular carrier 8 constituting the catalyst of the present invention includes graphite,
Examples include amorphous carbon.

Among these carbons, graphite is preferably used. As mentioned above, the essential supporting components constituting the catalyst of the present invention are sodium metal (a) and potassium metal (b).
However, if the composition is within the scope of the present invention, the supporting component may contain other components as necessary in addition to the essential alkali metal mixture. It may be supported.

Here, when the supported component consists only of the alkali metal mixture, it is a liquid or solid material consisting of a sodium-potassium alloy, but when the supported component is a mixture of the alkali metal mixture and the other components, it is in the form of a paste. It is.

The catalyst of the present invention can be prepared by various methods.

First, the compression-molded granular carrier field constituting the catalyst of the present invention is
It can usually be prepared by the following method. The carbon (c) and anhydrous potassium carbonate having the specific properties (
d) A powder composition consisting of a tablet molding machine, a compression molding machine,
Compression molding is performed using a pelletizer or the like. At that time, the compression-molded granular carrier 8 can be obtained by molding so that the pore volume ratio and compressive strength after molding are within the above ranges.
The shape of this compression-molded granular carrier may be any shape, but it is usually shaped into a tablet, pellet, ball, etc., and the particle size is usually 0.5 m1 or more.
Preferably it is in the range of 1 to 10 mm. The catalyst of the present invention is prepared by supporting the above-mentioned support component on the compression-molded granular carrier prepared by the above-mentioned method.

Various methods can be employed to support the above-mentioned supporting components on the compression-molded granular carrier circle. In either case, when sodium metal (a) is used as the alkali metal of the supported component, this sodium metal (
When a) comes into contact with anhydrous potassium carbonate (d) under heating, the alkali metal causes an exchange reaction to produce potassium metal and anhydrous sodium carbonate, so the sodium metal ( It is necessary to adjust the compositions of both components a) and potassium metal (b) to fall within the range of the present invention. Therefore, as the alkali metal component before being supported, sodium metal can be used alone, or an alloy of sodium metal and potassium metal can be used.

Specifically, the following method can be exemplified as the supporting method. A method of bringing monosodium metal and the compression-molded granular carrier into contact with each other under heating and stirring in an inert gas atmosphere.

[A method of bringing a mixture consisting of sodium metal and optionally other supporting components into contact with the compression-molded granular carrier leaf under heating and stirring in an inert gas atmosphere.

[(1) An alloy of sodium metal and potassium metal and the compression-molded granular carrier (self) in an inert gas atmosphere,
Method of contacting under heating and stirring.

[a) A method in which a mixture consisting of an alloy of sodium metal and potassium metal and optionally other supporting components is brought into contact with the compression-molded granular carrier [in an inert gas atmosphere while heating and stirring. The temperature during the supporting treatment is usually in the range of 150 to 400°C, but the catalytic activity
In order to obtain a catalyst with excellent catalyst life and selectivity to dimerization products, it is preferable to carry out the supporting treatment at a temperature in the range of 200 to 350°C.

Conventionally known α-olefin dimerization catalysts have been commonly used in areas where the conversion rate of α-olefin is high, but their drawbacks are that the activity of the catalyst is significantly reduced, and it is difficult to reduce the conversion rate of α-olefin. However, even if the catalyst was used, it was not possible to significantly reduce the activity of the catalyst and improve the selectivity to dimerized products.

In contrast, compared to any conventionally known catalyst, the catalyst of the present invention not only suppresses the decrease in activity even in the region where the conversion rate of α-olefin is high, but also is low, especially when the rate of change of α-olefin is 5.
In the range of 0% or less, the decrease in catalyst activity is significantly suppressed, the catalyst life is long, and the selectivity to dimerization products is high. The catalyst of the present invention is used in the dimerization reaction or co-dimerization reaction of α-olefin.

Specific examples of α-olefins include lower α-olefins such as ethylene, propylene, 1-butene, isobutylene, and 1-benzene. Among these dimerization reactions or co-dimerization reactions, production of 4-methyl-1-benzene by dimerization of propylene, production of 3-methyl-1-benzene by co-dimerization of 1-butene and ethylene,
Preference is given to using the catalyst of the invention for the production of 2-methyl-1-benzene by co-dimerization of isobutylene and ethylene, in particular for the production of 4-methyl-1-benzene by co-dimerization of propylene.
Preference is given to using the catalyst of the invention for the production of 1-benzene. The dimerization reaction or co-dimerization reaction of α-olefin using the catalyst of the present invention is carried out by a gas phase method or a liquid phase method under heating, but it is preferably carried out by a gas phase method.

The temperature when carrying out the reaction by the gas phase method is usually 0 to 300°C.
℃, preferably 100 to 200℃. The pressure during the reaction is usually in the range of normal pressure to 200 k9/Crill-G, preferably 20 to 150 k9/Crill-G. Although the reaction can be carried out in a fixed bed system or a fluidized bed system, it is preferable to carry out the reaction in a fixed bed system. When the reaction is carried out in a fixed bed method, the liquid hourly space velocity (LHSV) of α-olefin is usually 0.1 to 10 h.
r: 1, preferably in the range of 0.5 to 5 hr-1. After the reaction, the unreacted α-
The olefin and product are separated, and the unreacted α-olefin is recycled and reused in the reaction. EXAMPLES Next, the method of the present invention will be specifically explained using Examples, but the present invention is not limited thereto. The physical properties of the carrier and supported catalyst shown in the examples were measured as follows.

(1) Measurement of particle size distribution of raw powder of anhydrous potassium carbonate Combine JIS standard standard sieves from 16 mesh to 200 mesh, put a sample of raw powder of anhydrous potassium carbonate of about 1509 on top of the sieves, and place the whole into a polyethylene sieve. Put it in a bag and seal it.

This sieve was set in a low-tap type vibrating sieve shaker (19-45 manufactured by Kurihara Seisakusho), and sieved for 10 minutes under the conditions of shaking at 290 times/min and hammering at 156 times/min. The weight of the anhydrous potassium carbonate on each sieve after sieving was measured, the weight percentage was calculated, and the average particle size was determined from the RRS diagram. (2) Measurement of pore volume ratio of carrier Using approximately 109 carrier samples that had been heated and dried at 300°C for 2 hours, the specific gravity of the carrier was measured in mercury and carbon tetrachloride at 40°C. The ratio of the pore volume to the volume of the pore volume was determined as a volume percentage using the following formula as the pore volume ratio.

Here, DH and Dcce4 represent the specific gravity of the carrier measured in mercury and carbon tetrachloride, respectively, and ρHg
&ρCCl4 represent the densities of mercury and carbon tetrachloride at 40°C, respectively. (3) Measurement of the graphite content in the carrier 50f!, which was heated and dried at 300°C for 2 hours in advance! Add 100 d of water and 20 ml of methanol to the carrier sample,
After stirring with a magnetic stirrer for 20 minutes,
Further, the mixture was stirred for 30 minutes using an ultrasonic cleaner.

After washing the liberated graphite with water, it was dried at 100°C for 2 hours, the weight was measured, and the weight was expressed as a percentage by weight relative to the anhydrous potassium compound in the carrier. (4) Measurement of supported alkali metal component composition About 29 nm of the supported catalyst was accurately weighed, and 151 n of water was added in a nitrogen atmosphere.
1 was added, and the amount of hydrogen gas generated was measured using a gas bottle.

The temperature at the time of measurement is TCC), the pressure is P (MlLHg), T
The partial pressure of water at CC) is PH2O (MlLHg), the amount of gas generated is V (ml), the amount of alkali metal supported in the measured supported catalyst M (9) is A (9), and the carbon content is C (
9) And anhydrous potassium carbonate 100f! The values of A and B were determined from the following formula, where B (f! atoms) is the amount of supported alkali metal. On the other hand, 50 d of anhydrous isopropyl alcohol was added to the supported catalyst 29 in a nitrogen atmosphere, and 1
After standing for a period of time, the carrier and other solids were centrifuged.

The amounts of sodium alkoxide and potassium alkoxide eluted into the isopropyl alcohol thus obtained were measured by atomic absorption spectrometry, and the Na/K ratio was determined from both values. In addition, the amount of Na and the amount of K with respect to anhydrous potassium carbonate 1009 in the supported alkali metal component constituting the supported catalyst are as follows:
00f! It was determined by the following formula from the supported alkali metal amount B (9 atoms) and the Na/K ratio.

(5) Measurement of bulk density of raw powder of anhydrous potassium carbonate It has a sample drop opening at the lower end and has an inner diameter of 26.5 wLm1.The inner diameter at the upper end is 94 mm, the height is 100 mm, and the internal volume is 150 m1. A certain funnel was fixed vertically so that the height of the funnel to the sample drop opening at its lower end was 100 mm.

Directly below the sample droplet of this funnel, there is a
A cylindrical receiver with 1 mTIL and an internal volume of 98.0 m1 was placed. Pour the powder of anhydrous potassium carbonate sample into the funnel;
The sample drop port at the bottom was opened and the sample powder was dropped into the receiver. The raised sample at the top of the receiver was ground horizontally.
The weight of the sample in the receiver was measured and the bulk density was determined. Other physical properties were measured by conventional methods.

Example 1 (1) Preparation of catalyst A particle size distribution was prepared in which the average particle size was 300 μ, 4.8% was less than 100 μ, and 4.2% was more than 600 μ and up to 1000 μ. It has a bulk density of 0.79.
/ml of anhydrous potassium carbonate containing 0.5% by weight of graphite based on the anhydrous potassium carbonate. Diameter 3m'' height 3r! A cylindrical carrier of Lm was compressed into tablets.

After drying 97.5 g of this carrier at 350°C in a nitrogen stream for 2 hours, 2.59 g of sodium was added in a nitrogen atmosphere, and the mixture was stirred at 230°C for 5 hours to prepare a catalyst. The physical properties of the carrier and supported catalyst are shown in Table 1 below together with the results of each example. (2) Dimerization reaction A propylene dimerization reaction was carried out using the catalyst prepared in (1) above.

A pressure-resistant gas phase reactor was filled with catalyst, and propylene was heated at a liquid hourly space velocity (LHSV) of 0.85 h while maintaining the reactor pressure at 100k9/CTil-G and temperature at 157°C.
Continuous reaction was carried out by supplying at r-1. As a result, the propylene conversion rate reached a maximum of 85% after 5 hours, and then gradually decreased. The half-life of maximum activity, ie, the time required for the maximum conversion of propylene to be halved, was 1800 hours. Further, the content of 4-methyl-1-benzene in the hexene fraction of the product was 92%. Example 2 Using the catalyst prepared in Example 1 (1), the dimerization reaction of propylene was carried out at LHSV 2, 70 hr-1, and 150°C.
The test was carried out in the same manner as in Example 1 (2) except that the test was carried out under the following conditions.

The results are shown in Table 1. Examples 3 to 7 Example 1 (
Using anhydrous potassium carbonate having the same particle size distribution as that used in Example 1, the carriers shown in Table 1 were compressed into tablets with varying graphite content, pore volume ratio, and compressive strength.

Using these supports, catalysts having the physical properties shown in Table 1 were prepared by a method similar to Example 1 (1). A propylene dimerization reaction was carried out under the same conditions as in Example 2 using these catalysts. The results are shown in Table 1. Comparative example
1 The catalysts shown in Table 1 were prepared by changing the loading conditions for sodium in Example 1 (1).

Using this catalyst, a propylene dimerization reaction was carried out under the same conditions as in Example 2. The results are shown in Table 1. Comparative Examples 2 to 4 The particles have a particle size distribution in which the average particle size is 450μ, 0.5% is less than 100μ, and 27.6% is more than 600μ and up to 1000μ, and the bulk density is is 1.1
Using anhydrous potassium carbonate of 9/ml, cylindrical supports shown in Table 1 with a diameter of 3 mm and a height of 3 mm having different graphite contents were prepared according to the method (1) of Example 1. It was molded into tablets.

Using this carrier, a catalyst having the physical properties shown in Table 1 was prepared by a method similar to Example 1 (1). Using this catalyst, a propylene dimerization reaction was carried out under the same conditions as in Example 2. The results are shown in Table 1. Comparative example 5~
7 Anhydrous potassium carbonate having the same particle size distribution as that used in Example 1 (1) was used, and the graphite content was adjusted to 0.
The carriers shown in Table 1 were compressed into tablets by changing the pore volume ratio and compressive strength to 5% by weight.

Using this carrier, a catalyst having the physical properties shown in Table 1 was prepared by a method similar to Example 1 (1). A propylene dimerization reaction was carried out under the same conditions as in Example 2 using these catalysts. The results are shown in Table 1. As is clear from Table 1 above, the catalyst of the present invention has particularly remarkable effects on catalyst activity, catalyst life, and selectivity to dimerization products compared to the catalyst of the comparative example.

Claims (1)

[Scope of Claims] 1. A catalyst in which an alkali metal [A] is supported on a carrier 5 whose main component is anhydrous potassium carbonate, in which (i) the alkali metal [A] is supported by sodium metal (a) and potassium metal (b); ), the composition of which is sodium metal (
a) in the range of 20 to 90 g at % and potassium metal (b) in the range of 10 to 80 g at %; (ii) the carrier [B] consists of carbon (c) and anhydrous potassium carbonate (d); and the content of the carbon (c) is in the range of 0.6 to 3% by weight based on the anhydrous potassium carbonate (d); (ii)
i) The anhydrous potassium carbonate constituting the carrier [B] has an average particle size of the raw powder before compression molding in the range of 150 to 600μ, and the powder with a particle size of less than 100μ is in the range of 1 to 15% by weight. and (iv) the carrier [B] has a pore volume ratio of 22 to 38%.
and has a compressive strength of 1.5 to 15 kg/
A catalyst for the dimerization of α-olefins, characterized in that it is in the range of cm^2-G. 2 The composition of the alkali metal [A] is sodium metal (a
2.) potassium metal (b) in the range of 15 to 70 gram at %. 3. The catalyst according to claim 1 or 2, wherein the carrier [B] contains carbon in a range of 0.8 to 2% by weight based on the anhydrous potassium carbonate (d). 4 The raw powder of anhydrous potassium carbonate constituting the carrier [B] before compression molding has an average particle size in the range of 200 to 600 μ, and the powder with a particle size of less than 100 μ is in the range of 2 to 10% by weight. The catalyst according to any one of claims 1 to 3, wherein the catalyst is anhydrous potassium carbonate having a particle size distribution in the range of 2 to 15% by weight of powder having a particle size of more than 600 μm. 5 The pore volume ratio of the carrier [B] is in the range of 26 to 33%, and the compressive strength is 2 to 10 kg/cm^2
The catalyst according to any one of claims 1 to 4, which is a compression-molded granular carrier in the range -G. 6. The catalyst according to any one of claims 1 to 5, wherein the carbon (c) is graphite.