JPS6325817B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to catalysts for the 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 can be used for a long period of time without causing a decrease in activity.

Dimers or codimers of α-olefins, typified by 4-methyl-1-pentene, are used as monomers for producing polyolefins.

A number of basic catalysts have been proposed as catalysts for producing the 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 to the desired product, or short catalyst life even with high activity, making them difficult to use on an industrial scale. There are few that can be effectively used in implementation. Among these conventionally known basic catalysts, catalysts in which sodium metal is dispersed in granular anhydrous potassium compounds are disclosed in Japanese Patent Publication No. 42-22474 and Japanese Patent Publication No. 1973.
This is proposed in Publication No. -25344. Similarly, catalysts in which molten alkali metals such as lithium, sodium, and potassium are directly supported on carriers such as graphite, alumina, alkali metal silicates, alkaline earth metal silicates, oxygen-containing compounds, and magnesia, -1166, British Patent No. 903014, US Pat. No. 3,175,020, US Pat. No. 3,095,461, and US Pat. No. 3,305,599. These catalysts have catalytic activity,
Although it has advantages over other basic catalysts in terms of selectivity to the target product and ease of catalyst preparation and handling during industrialization, catalyst activity decreases in a relatively short period of time. must be replaced frequently. Therefore, in methods using these catalysts, the biggest challenge in any catalyst system is to suppress the decrease in catalyst activity.

The present invention was made in view of the above-mentioned current situation, and its purpose is to provide a catalyst for dimerization or co-dimerization of α-olefins that has high selectivity to the target product and has a long life.

To summarize the present invention, the present invention provides a powdered anhydrous potassium compound and a potassium atom of 0.1 per gram atom of the powdered anhydrous potassium compound.
The present invention relates to a catalyst for dimerization or co-dimerization of α-olefins, characterized in that a mixture consisting of sodium metal in the range of 30 to 30 gram atoms is supported on a carrier.

In the catalyst of the present invention, specific examples of the powdered anhydrous potassium compound as a component include powdered anhydrates of inorganic potassium compounds such as potassium carbonate, potassium silicate, potassium sulfate, potassium nitrate, potassium chloride, and potassium bromide. Can be mentioned. Among these powdered anhydrous potassium compounds, it is preferable to use powdered anhydrous potassium carbonate. These powdered anhydrous potassium compounds are anhydrous potassium compounds whose particle size is usually 200 μm or less, preferably in the range of 1 to 100 μm.

The mixture consisting of a powdered anhydrous potassium compound and sodium metal as the constituent components of the catalyst of the present invention is
It is a paste-like mixture produced by blending a powdered anhydrous potassium compound and molten sodium metal in a range of usually 0.1 to 30 gram atoms per gram atom of potassium atom of the powdered anhydrous potassium compound. is a paste-like mixture produced by blending a powdered anhydrous potassium compound and 0.5 to 20 gram atoms of molten sodium metal per gram atom of potassium in the powdered anhydrous potassium compound. It is preferable. If the proportion of sodium metal in this mixture is less than 0.1 gram atom per gram atom of potassium in the powdered anhydrous potassium compound, the activity of the catalyst will decrease.
If the amount exceeds 30 gram atoms, the initial activity of the catalyst will be high, but the sodium metal will become spheroidized and easily peel off from the carrier, and tar-like by-products will increase, resulting in a faster rate of activity decline. In a paste-like mixture produced by blending a powdered anhydrous potassium compound and molten sodium metal in the above proportions, a portion of the potassium ions of the potassium compound undergoes ion exchange with sodium metal to produce a sodium compound. Since potassium metal is also produced at the same time, the composition ratio of the potassium compound and sodium metal in the prepared catalyst is not necessarily within the range of the above-mentioned mixing ratio. The mixture consisting of powdered anhydrous potassium compound and sodium metal, which are the constituent components of the catalyst of the present invention, can be prepared by adding sodium metal to powdered anhydrous potassium compound under heating and stirring and kneading, or by adding powdered anhydrous potassium compound to molten sodium metal. It can be prepared by adding a potassium compound and stirring and kneading while heating. The temperature during stirring and kneading is usually 100 to 500.
℃, preferably in the range of 200 to 400℃. A pasty mixture of anhydrous powdered potassium compound and sodium metal is obtained by this method.

The catalyst of the present invention is obtained by supporting the above-mentioned paste-like mixture consisting of a powdered anhydrous potassium compound and sodium metal on a carrier. Specific examples of carriers include alumina, silica/alumina, silica, titanium oxide, zinc oxide,
Examples include oxides such as magnesium oxide and sodium oxide, sodium carbonate, magnesium carbonate, graphite, diatomaceous earth, sponge-like metals, silicon carbide, and pumice. Among these carriers,
Alumina, silica, silica/alumina, activated carbon,
Preference is given to using magnesium oxide, sodium oxide, sodium carbonate, magnesium carbonate, in particular alumina, silica, silica-alumina or activated carbon. Also,
These carriers usually have a surface area of 1 to 800
m ² /g supports are used, but it is preferred to use supports with surface areas in the range 100 to 500 m ² /g. In addition, even if the shape of these carriers is granular, such as pellets, tablets, spheres, or crushed shapes,
Although it may be in powder form, it is preferable to use a granular carrier. If a granular carrier is used, the particle size of the carrier ranges from 0.3 to 10 mm, preferably from 1 to 10 mm. A conventionally known method is used to support the paste-like mixture consisting of a powdered anhydrous potassium compound and sodium metal on a carrier. Specifically, a method of bringing the pasty mixture into contact with a carrier while stirring;
A method includes adding a powdered anhydrous potassium compound to a carrier, stirring the mixture, adding sodium metal under heating to form a paste-like mixture of the powdered anhydrous potassium compound and sodium metal on the carrier, and simultaneously supporting the mixture on the carrier. Can be mentioned. The temperature during support is usually 100 to 500°C, preferably
The temperature ranges from 200 to 350°C.

In preparing the catalyst of the present invention, the blending ratio of the powdered anhydrous potassium compound and the carrier is usually 0.1 to 50 parts by weight, preferably 0.5 parts by weight, based on 100 parts by weight of the carrier.
The amount ranges from 1 to 20 parts by weight, more preferably from 1 to 10 parts by weight. In addition, the blending ratio of sodium metal to the carrier is usually 0.1 parts by weight per 100 parts by weight of the carrier.
It ranges from 0.5 to 10 gram atoms, preferably from 0.5 to 10 gram atoms.

The catalyst of the present invention is used in the dimerization reaction or co-dimerization reaction of α-olefin. Specifically, α-olefins include ethylene, propylene, 1
Examples include lower α-olefins such as -butene, isobutylene, and 1-pentene. Among these α-olefins, 4 due to dimerization of propylene
The present invention is applicable to the production of methyl-1-pentene, the production of 3-methyl-pentene by co-dimerization of 1-butene and ethylene, and the production of 2-methyl-1-pentene by co-dimerization of isobutylene and ethylene. Preference is given to using catalysts, and particular preference is given to using the catalysts of the invention for the production of 4-methyl-1-pentene by dimerization of propylene.

The dimerization reaction or co-dimerization reaction of α-olefin using the catalyst of the present invention is carried out under heating by a gas phase method or a liquid phase method, but it is preferably carried out by a gas phase method. When the reaction is carried out by a gas phase method, the temperature is usually 0 to 300°C, preferably 100 to 300°C.
It is ℃. The pressure during the reaction is usually normal pressure to 200℃
Kg/cm ² -G, preferably 20 to 150Kg/cm ² -G
is within the range of The reaction can be carried out in a fixed bed method or in a fluidized bed method, but
Preferably, a fixed bed method is used. When the reaction is carried out in a fixed bed mode, the liquid hourly space velocity (LHSV) of the α-olefin is generally in the range of 0.1 to 10 hr ⁻¹ , preferably 0.5 to 5 hr ⁻¹ . After the reaction is completed, the final reacted α-olefin and the product are separated from the mixture according to a conventional method, and the unreacted α-olefin is recycled and reused in the reaction.

Next, the method of the present invention will be specifically explained using Examples, but the present invention is not limited thereto.

Example 1 (1) Catalyst preparation 6 g of powdered anhydrous potassium carbonate of 50 to 100 μm was dried in a nitrogen stream at 200°C for 15 hours, and further dried until the water content of this powdered anhydrous potassium carbonate was reduced to 300 ppm. After that, 3g of sodium was added under nitrogen atmosphere,
The mixture was heated at 300℃ under nitrogen atmosphere for 2 hours.
Stir vigorously for an hour to obtain a paste-like mixture. On the other hand, the average fractured to 2.4 to 3.3 mm
91 g of activated carbon having a surface area of 400 cm ² /g was dried in the same manner as the powdered anhydrous potassium carbonate. The paste mixture was added to this granular activated carbon under a nitrogen atmosphere, stirred at 250°C for 3 hours,
A catalyst was prepared.

(2) Dimerization reaction A propylene dimerization reaction was carried out using the catalyst prepared in (1) above. A pressure-resistant gas phase reactor is filled with catalyst, and the pressure of this reactor is set to 100Kg/cm ² −
Continuous reaction was carried out by supplying propylene at a liquid hourly space velocity (LHSV) of 0.85 hr ^-1 while maintaining G and temperature at 157°C. As a result, the propylene conversion rate reached a maximum of 75% after 5 hours, and then gradually decreased. The half-life of maximum activity, that is, the time required for the maximum conversion of propylene to be halved, was over 1500 hours. Further, the content of 4-methyl-1-pentene in hexene of the product was 90%.

Comparative Example 1 A catalyst was prepared in the same manner as in Example 1, except that 0.25 g of powdered anhydrous potassium carbonate, 3 g of sodium, and 98.9 g of granular activated carbon were used in the catalyst preparation of Example 1 (1). . Using this catalyst, a propylene dimerization reaction was carried out in the same manner as in Example 1 (2). As a result, the highest conversion rate of propylene was 45%, and the half-life was 150 hours. Also,
The content of 4-methyl-1-pentene in hexene of the product was 70%.

Comparative Example 2 91g of the same activated carbon used in Example 1 (1)
was dried in the same manner. 3 g of sodium was added to this activated carbon under a nitrogen atmosphere, and the mixture was stirred at 250° C. for 3 hours to prepare a catalyst. Using this catalyst, a propylene dimerization reaction was carried out in the same manner as in Example 1 (2). As a result, the conversion rate of propylene 10 hours after the start of the reaction was 40%, and the half-life was 120 hours. The content of 4-methyl-1-pentene in the hexene product was 40%.

Example 2 A catalyst was prepared in the same manner as in Example 1, except that alumina pellets with a surface area of 300 cm ² /g and a size of about 3 mm were used in place of the granular activated carbon in (1) of Example 1. Prepared. Using this catalyst, a propylene dimerization reaction was carried out in the same manner as in Example 1 (2). As a result, the highest conversion rate of propylene was 70% and the half-life was 500 hours. Also,
The content of 4-methyl-1-pentene in hexene of the product was 88%.

From the comparison between the Examples and Comparative Examples, it is clear that the selectivity and activity sustainability of the catalyst of the present invention, in which a mixture of powdered anhydrous potassium compound and metallic sodium is supported on a carrier at a ratio within a specific range, is clear.

Claims (1)

[Claims] 1. A powdered anhydrous potassium compound and a mixture of sodium metal in a range of 0.1 to 30 gram atoms per gram atom of potassium in the powdered anhydrous potassium compound are supported on a carrier. A catalyst for dimerizing or non-dimerizing α-olefin. 2. The catalyst according to claim 1, wherein the mixture is a mixture of a powdered anhydrous potassium compound and sodium metal in an amount of 0.5 to 20 gram atoms per gram atom of potassium of the powdered anhydrous potassium compound. . 3. Claim 1 or 2, wherein the powdered anhydrous potassium compound is granular anhydrous potassium carbonate.
Catalysts as described in section. 4 Powdered anhydrous potassium compound is 1 or
Claims 1 to 3 are powdered anhydrous potassium compounds having a particle size in the range of 100 μm.
Catalyst according to any of paragraphs. 5. The catalyst according to any one of claims 1 to 4, wherein the carrier is alumina, silica, silica-alumina, or activated carbon. 6. The catalyst according to any one of claims 1 to 5, wherein the carrier has a particle size in the range of 1 to 10 mm. 7 The blending ratio of the powdered anhydrous potassium compound is the carrier
Catalyst according to any one of claims 1 to 6, in a range of 0.5 to 10 parts by weight per 100 parts by weight.