JPH0341036A - Production of 1-pentene by codimerization of ethylene and propylene - Google Patents

Abstract

PURPOSE:To obtain 1-pentene in high selectivity by codimerizing ethylene with propylene by means of a fixed bed method in the presence of a catalyst prepared by supporting an alkali metal on a compression molded granular carrier comprising anhydrous potassium carbonate and carbon. CONSTITUTION:Ethylene is codimerized with propylene in the molar ratio of 0.30-0.95 by a fixed bed method in the presence of a catalyst prepared by supporting alkali metals on a compression molded granular carrier comprising anhydrous potassium carbonate and carbon to give 1-pentene in a high productivity based on unit weight of the catalyst. The alkali metals consists of 20-90g atom % Na and 80-10g atom % K, the carrier contains 0.6-3wt.% carbon based on anhydrous K2CO3 and has 22-38% pore volume ratio and 1.5-15kg/cm<2> compression strength. Anhydrous K2CO3 has 150-600mum average particle diameter and 0.50-0.70g/ml bulk density as raw powder before the compression molding.

Description

Detailed Description of the Invention The present invention relates to a method for producing 1-pentene by co-dimerization of ethylene and propylene in the presence of a catalyst. The present invention relates to an industrially advantageous method for producing (1)-pentene by dimerization in a high production amount per unit weight of catalyst and with high selectivity.

Various basic catalysts for the trimerization and co-dimerization of α-olefins have been proposed in the past, and are made by supporting an alkali metal on compression-molded granular carriers made of anhydrous potassium carbonate and graphite. The catalyst was published by Special Publication Publication No. 59-405.
This is already known as described in Japanese Patent Publication No. 03 and Japanese Patent Publication No. 59-40506. In the above-mentioned publication, a catalyst is prepared using anhydrous potassium carbonate having a bulk density of 0.7 g/ml as the anhydrous potassium carbonate constituting the carrier, and using such a catalyst, co-dimerization of propylene is carried out. It is stated that 4-methyl-1-pentene can be prepared.

However, according to such conventional catalysts, especially when producing l-pentene through co-dimerization of ethylene and propylene, the catalytic activity due to the formation of oligomers is low because the reactivity of ethylene is much higher than that of propylene. Deterioration easily occurs, the selectivity for 1-pentene is low, and the production amount per weight of catalyst is also low.

Furthermore, the conventional catalysts described above lose their mechanical strength during use and turn into powder in a relatively short period of time, so especially when used as a fixed bed catalyst, the pressure loss in the reaction tube increases over time. rapidly increases, forcing the catalyst to be replaced. From this point of view, when conventionally known catalysts are used, the production amount of 1-pentene per weight of the catalyst is low.

The present invention was made to solve the above-mentioned problems in the production of 1-pentene by co-dimerization of ethylene and propylene using a conventional α-olefin trimerization catalyst. 1-pentene can be produced industrially with high selectivity and high yield by co-dimerizing ethylene and propylene by selecting reaction conditions in the presence of improved catalysts with high activity and long lifetime. The object of the present invention is to provide a manufacturing method that is economically advantageous.

The present invention provides a method for producing 1-pentene by codimerizing ethylene and propylene in the presence of a catalyst in a fixed bed system, in which (A) the catalyst converts an alkali metal into anhydrous A catalyst supported on a compression-molded granular carrier consisting of potassium carbonate and carbon, wherein (a) the alkali metal is 20 to 90 g of sodium;
(b) the compression-molded granular carrier contains 0.6 to 3% by weight of carbon relative to anhydrous potassium carbonate;
Pore volume ratio of 38% and 1.5-15 kg/co!
has a compressive strength of 15% by weight, particle size 600μ
The powder exceeding m has a particle size distribution in the range of 1 to 20% by weight, and further has a bulk density in the range of 0.50 g / ml or more and less than 0.70 g / ml, B) Ethylene and propylene are supplied at an ethylene/propylene molar ratio in the range of 0.30 to 0.95, and the pressure is 30
kg/cm! The above is characterized in that the reaction is carried out at a temperature of 80 to 140°C.

The catalyst used in the method of the present invention has an alkali metal supported on a compression-molded granular carrier consisting of anhydrous potassium carbonate and carbon, and the supported alkali metal includes 20 to 90 g at % of sodium and 80 to 10 g at % of potassium. It preferably consists of 30 to 85 g at % of sodium and 70 to 15 g at % of potassium. The alkali metal is preferably supported in a proportion of 0.5 to 10% by weight based on anhydrous potassium carbonate, and in particular,
It is preferable that it is supported at a ratio of 1 to 5% by weight.

In the supported alkali metal, sodium is 90g at%
When potassium is less than Log atomic %, the catalyst activity and the desired codimerization product 1-
It has low selectivity to pentene, and in particular, the induction period before peak activity is extremely long. On the other hand, when the supported alkali metal contains less than 20 g at % of sodium and more than 80 g at % of potassium, the resulting catalyst has high initial activity, but the catalyst activity decreases markedly over time and the catalyst life is shortened. is short.

Furthermore, if the proportion of the alkali metal supported in the anhydrous potassium carbonate is too small, the catalytic activity will be low, while if it is too large, the alkali metal will easily peel off from the anhydrous potassium carbonate, which is not preferable.

When only sodium and potassium are supported on the carrier, a liquid or solid sodium-potassium alloy is usually used. However, in the method of the present invention, the catalyst used may have components other than the alkali metal supported on a carrier, if necessary, and in such a case, for example, a paste containing the alkali metal and other components A mixture of is used.

In the catalyst used in the method of the present invention, the carrier is a granular carrier obtained by compression molding a mixture of anhydrous potassium carbonate and carbon. The carbon content in such a carrier is 0.6 to 0.6 to anhydrous potassium carbonate.
It is in the range of 3% by weight.

When the content of carbon in the carrier is less than 0.6% by weight based on anhydrous potassium carbonate, the catalyst activity, selectivity to the desired trimerization product, catalyst life, etc. are low. However, even if the carbon content in the carrier exceeds 3% by weight,
No particular improvement in catalytic activity or target selectivity to 1-pentene was observed, and furthermore, by compression molding, the mixture of anhydrous potassium carbonate and carbon had a compressive strength of 1.5 kg/cJ.
It becomes difficult to mold into a granular support larger than AG, and as a result, the catalyst life is shortened, making it impossible to obtain a practical catalyst. In particular, in the method of the present invention, in order to obtain a catalyst with a long catalyst life and high selectivity to 1-pentene, the carbon content in the carrier should be between 0.8 and 1.
Preferably, it is in the range of 2% by weight.

Examples of the carbon include graphite and amorphous carbon, and graphite is particularly preferably used.

In the method of the present invention, regarding the catalyst used, the anhydrous potassium carbonate constituting the carrier has an average particle size of 150 to 600 μm as an original material before compression molding, and powder with a particle size of less than 100 μm is ~15% by weight,
Powder having a particle size exceeding 600 μm has a particle size distribution in the range of 1 to 20% by weight, and further has a bulk density of 0.50 g 7
m1 or more and less than 0.70 g 7 m1, in particular, the average particle size is 200 to 500 g.
μm, and the powder with a particle size of less than 100 μm is 2 to 1
The powder has a particle size distribution of 2 to 15% by weight, and a bulk density of 0.53 to 0.69 g/ml. It is preferable.

In particular, in the method of the present invention, the bulk density is 0.55 to 0.
．． 1 per unit weight of the catalyst by preparing a compression-molded granular support with graphite using anhydrous potassium carbonate raw material in the range of 68 g/ml and using a catalyst comprising an alkali metal supported on such a support. - High production of pentene, high conversion rate and high selectivity,
1-pentene can be produced.

The original anhydrous potassium carbonate with a narrow particle size distribution, such as a normal commercially available product, has an average particle size in the range of 350 to 800 μm, and 1 weight of powder with a particle size of less than 100 μm and powder with a particle size of more than 600 μm is 1 weight. %, and even if such anhydrous potassium carbonate is compression molded together with carbon, a granular support with sufficient strength cannot be obtained. Even if the above-mentioned alkali metal is supported on this, the resulting catalyst is It is inferior in both longevity and selectivity to the target 1-pentene.

Furthermore, in the method of the present invention, when preparing the catalyst used, the bulk density of the raw material is 0.50 g 7 ml or more and less than 0.70 g 7 ml, preferably 0.53 g 7 ml or more.
By using anhydrous potassium carbonate in the range ~0.69 g/m+, most preferably 0.55-0.68 g/ml, the mechanical strength is significantly improved, thus
A catalyst with a significantly long catalyst life can be obtained. That is,
In this way, by preparing a compression-molded granular carrier using an anhydrous potassium carbonate raw material with high porosity, it has high catalytic activity and a long life of more than one year, especially in continuous reactions using a fixed bed system. catalyst can be obtained.

However, the bulk density of the anhydrous potassium carbonate original is 0.50 g/
If it is smaller than ml, it will be crushed when mixed with carbon before compression molding, and the raw powder will not have the above particle size distribution, and a granular carrier having a strength in the above range will be obtained by compression molding. However, the life of the resulting catalyst is rather shortened.

In the catalyst used in the method of the present invention, the carrier is a granular carrier obtained by compression molding anhydrous potassium carbonate and carbon as described above, and has a pore volume ratio in the range of 22 to 38%. , and the compressive strength is 1.5 to 15+r/c
n! It is necessary to be within the range of . When the pore volume ratio and compressive strength of the carrier are outside the above ranges, and the pore volume ratio is large and the compressive strength is small, the resulting catalyst has a relatively high initial activity, but the catalytic activity decreases over time. Moreover, since the catalyst has insufficient strength, it is easy to disintegrate and powder over time during use, and the catalyst life is short. On the other hand, when the pore volume ratio is low and the compressive strength is high, the resulting catalyst has low activity and low selectivity to the target 1-pentene.

However, in the granular carrier obtained by compression molding anhydrous potassium carbonate and carbon according to the method of the present invention,
Pore volume ratio of 22 to 38%, preferably 26 to 33%
and compressive strength of 1.5 to 15 kg/c
olG, preferably 2-10 kg/cn! By setting G within the range, an industrially useful catalyst with excellent catalytic activity, catalyst life and selectivity to dimerization products can be obtained, and 1-pentene can be produced industrially advantageously. can.

The catalyst used in the method of the invention can be prepared by various methods. First, a carrier is usually prepared by the following method. Carbon and raw powder of anhydrous potassium carbonate having the above-mentioned properties are sufficiently mixed, and this mixture is processed by a tablet molding machine, compression molding machine, pelletizer, etc. so that it has the above-mentioned pore volume ratio and compressive strength. ,
Compression molding into a granular carrier. The shape of the compression-molded granular carrier obtained in this way is not particularly limited, but it is usually cylindrical, tablet-shaped, pellet-shaped, spherical, etc., and the particle size is usually 0.510 or more. , preferably 1-1
011, particularly preferably in the range of 3 to 5 +n.

Various methods can be used to support the alkali metal on such a carrier. When sodium is brought into contact with anhydrous potassium carbonate under heat, an alkali metal exchange reaction occurs with the potassium, resulting in potassium and anhydrous sodium carbonate in the carrier. Therefore, in the preparation of the catalyst according to the present invention, the necessary amounts of sodium and potassium can be supported on the carrier by using only sodium in consideration of the above-mentioned alkali metal exchange reaction. Of course, sodium and potassium, for example, a sodium-potassium alloy as described above, can also be used to support them on a carrier.

Specifically, the following method may be used to support the alkali metal on the carrier. That is, a mixture of sodium and other supported components as necessary, or a mixture of a sodium-potassium alloy and other supported components as necessary, is heated together with the compression-molded granular carrier in an inert gas atmosphere. By stirring downward, sodium and potassium and, if necessary, other supported components can be supported on the carrier.

As mentioned above, when an alkali metal is supported on a carrier, the heating temperature is usually in the range of 150 to 450°C, but it may affect catalyst activity, catalyst life, and dimerized biosubstances. In order to obtain a catalyst with excellent selectivity, in particular, 200
A range of ˜400° C. is preferable.

According to the method of the present invention, in the method of producing 1-pentene by codimerizing ethylene and propylene in a fixed bed method in the presence of the catalyst thus obtained,
Ethylene and propylene were supplied at an ethylene/propylene molar ratio of 0.30 to 0.90, and the pressure was 30 kg/
The reaction is carried out at a temperature of 80 to 130° C. at a temperature of 80 to 130° C.

The reaction is usually carried out by a continuous fixed bed flow method using a high-pressure tubular reactor with a tube diameter of 25 to 80 mm, but a solvent or accompanying gas may be used in addition to ethylene and propylene.

In the process of the invention, ethylene and propylene are passed through the fixed bed catalyst at an ethylene/propylene molar ratio in the range of 0.30 to 0.95. When this ethylene/propylene molar ratio is smaller than 0.30, 4-methyl-I-pentene is produced as a by-product due to trimerization of propylene, and 1-pentene, which is the desired codimerization product, is highly selective. It cannot be obtained through sex. On the other hand, when the ethylene/propylene molar ratio is greater than 0.95, 3-ethyl-1
A large amount of pentene is produced as a by-product, and l-pentene cannot be obtained with high selectivity.

The reaction temperature is 80-140°C, preferably 90-12°C.
It is in the range of 0°C. When the reaction temperature is lower than 80° C., the reactivity of the α-olefin is low and moreover, undesirable by-products are often produced. However, when the reaction temperature exceeds 140°C, a large amount of 2-pentene is produced and 1-
Not only is it not possible to obtain pentene with high selectivity, but also polymer substances adhere to the surface of the catalyst, leading to deterioration of the catalyst activity.

The reaction pressure ranges from 30 to 200 kg/adG, preferably from 40 to 150 kg/colG. When the reaction pressure is lower than 30 kg/ciG, the reaction rate is slow, which is disadvantageous for industrially producing 1-pentene. Although the upper limit of the reaction pressure is not particularly limited, it is usually 200 kg/aJG from a practical standpoint. Furthermore, the space velocity (L HSV) of a mixture of ethylene and propylene is typically between 0.1 and 15 hr-'
, preferably in the range of 0.5 to 10 hr-'.

Under such conditions, ethylene and propylene add 5% to the catalyst.
Contact is made for ~500 seconds.

Examples of the solvent or accompanying gas include mekun, ethane, propane, hexane, cyclohexane, octane,
Examples include saturated hydrocarbons such as decane, and when a solvent or accompanying gas is used in this way, it is desirable that the total concentration of ethylene and propylene be 30% by weight or more.

After completion of the reaction, 1-
Separate pentene from unreacted ethylene and propylene,
Unreacted materials are recycled and reused in the reaction.

1. As described above, in the method of the present invention, regarding the catalyst used, in preparing a compression-molded granular carrier consisting of anhydrous potassium carbonate and carbon, in particular, as anhydrous potassium carbonate,
By using a catalyst with a predetermined bulk density and appropriately selecting the reaction conditions, co-dimerization of ethylene and propylene can produce a high production amount per unit weight of catalyst.
In addition, 1-pentene can be industrially advantageously produced with high selectivity.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

In addition, below, the method for measuring the physical properties of the carrier and catalyst is as follows:
It is as follows.

A JIS standard sieve of 16 mesh to 200 mesh for canned potassium water was combined, about 150 g of anhydrous potassium carbonate original sample was placed on top of the sieve, and the whole was placed in a polyethylene bag and sealed. This sieve was attached to a loader tube type vibrating sieve shaker, and the number of shakes was 290 times/min, and the number of hammers was 156 times/min.
It was sieved for 10 minutes under the condition of 10 minutes.

After sieving in this way, the weight of anhydrous potassium carbonate on each sieve was measured, the weight percentage was calculated, and RR3
The average particle size was determined from the diagram.

The specific gravity of a carrier sample of about 10 g, which had been dried by heating at 300°C for 2 hours, was measured at 40°C in mercury and carbon tetrachloride.
The ratio of the pore volume to the volume of the carrier was defined as the pore volume ratio, and the volume percentage was calculated using the following formula.

00 Here, DHg and D CCI A are the specific gravity of the carrier measured in mercury and carbon tetrachloride, respectively, and pHg and ρCCl4 are the densities of mercury and carbon tetrachloride at 40°C, respectively.

Graphite A (carrier) 1001 Ill of water and 20 ml of methanol were added to 50 g of carrier sample which had been heated and dried in advance at 300°C for 2 hours.
After stirring with a magnetic stirrer for 1 minute, the mixture was further stirred with an ultrasonic cleaner for 30 minutes.

After washing the liberated graphite with water, it was heated at 100℃ for 2
After drying for a period of time, the weight was measured and the weight percentage relative to the anhydrous potassium carbonate in the carrier was determined.

15 ml of water was added to about 2 g of the precisely weighed catalyst in a nitrogen atmosphere, and the amount of hydrogen gas generated was measured using a gas villet. The temperature at the time of measurement is t ('c), and the pressure is P (wmHg
), the partial pressure of water at temperature t(”c) is expressed as P HzO(
mmHg), the amount of gas generated is V (ml), the amount of supported alkali metal in catalyst sample M (g) is A (g), and the graphite content is C (g), and the amount of supported alkali metal per 100 g of anhydrous potassium carbonate is The values of A and B were determined from the following equations, assuming that the amount was B (g atoms).

On the other hand, 50 ml of anhydrous isopropyl alcohol was added to 2 g of supported catalyst in a nitrogen atmosphere, and after being left at room temperature for 1 hour,
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 from both values Na/
The K ratio was determined.

In addition, the amount of sodium and potassium supported on the catalyst per 100 g of anhydrous potassium carbonate is the amount of alkali metal supported per 100 g of anhydrous potassium carbonate, B (
g atom) and the Na/K ratio using the following formula.

Amount of Na (g atoms/100g anhydrous potassium carbonate) = 4J
(g atoms/100g anhydrous potassium carbonate) = It has a drop opening at the lower end, and its inner diameter is 26°5N, the inner diameter at the upper end is 9.4 weight, the height is 1100u, and the internal volume is 150m1.
The height of the funnel to the sample droplet at the bottom is 1
It was fixed vertically so that the distance was 0.00 mm. Directly below the sample drop opening of this funnel is an inner diameter of 39 m, a height of 81 m, and an internal volume of 9 m.
An 8.0 ml cylindrical receiver was placed.

Anhydrous potassium carbonate sample powder was placed in the funnel, the sample drop opening at the bottom was opened, and the sample powder was dropped into the receiver.

The raised sample at the top of the receiver was cut horizontally, the weight of the sample powder in the receiver was measured, and the bulk density was determined.

Other properties were measured by conventional methods.

Example 1 (Preparation of catalyst) A particle size distribution having an average particle size of 280 μm, 6.9% by weight of particles with a particle size of less than 100 μm, and 3.4% by weight of particles with a particle size of more than 600 μm up to 1000 μm, Bulk density is 0.
1.1% by weight of graphite was added to anhydrous potassium carbonate having a pore volume of 68 g/ml and a pore volume of 0.45 m1/g, and after thorough mixing, it was poured into a cylindrical carrier with a diameter of 3n and a height of 3fl. It was molded into tablets.

The pore volume ratio of this carrier is 27%, and the compressive strength is 6.8 kg.
/ col G.

After drying 97.2 g of this carrier at 350° C. in a nitrogen stream, 2.8 g of metallic sodium was added in a nitrogen atmosphere, and the mixture was stirred at 240° C. for 5 hours to prepare a catalyst.

In the obtained catalyst, the supported alkali metals were 48 g at % of sodium and 52 g at % of potassium, and the amount supported relative to anhydrous potassium carbonate was 2.7% by weight.

The catalyst 161 thus prepared was packed into a tubular high-pressure gas phase reactor with an inner diameter of 501 m, and the pressure of this reactor was 100 m.
kg/ctAG, and while maintaining the temperature at 105°C, ethylene and propylene were supplied at a liquid hourly space velocity (LHS V) of 2.5 hr-' at an ethylene/propylene molar ratio of 0.55 to conduct a continuous reaction. Ta.

As a result of the reaction, the conversion rate of ethylene was 83 mol%, and the composition of the product was 93.2 mol% of -pentene, 2.
-Pentene was 1.4 mol%, 4-methyl-1-pentene was 3.0 mol%, 3-ethyl-I-pentene was 1.9 mol%, and others were 0.5 mol%.

Moreover, the conversion rate of ethylene shows little change over time, and 10
Total daily production was 98 g/g catalyst.

Examples 2 and 3 The ethylene/propylene molar ratio fed to the reactor was 0.8 and 0.3, respectively, as shown in Table 1.
Codimerization of ethylene and propylene was carried out in the same manner as in Example 1. The reaction results are shown in Table 1.

Comparative Example 1 Ethylene/propylene molar ratio supplied to the reactor was 1.1
Co-dimerization of ethylene and propylene was carried out in the same manner as in Example 1 except that. The reaction results are shown in Table 1.

In this reaction, 10 hours after the start of the reaction, the amount of reaction liquid discharged from the reactor was extremely reduced.

When the reactor was opened and examined, polymer substances were found to be attached to the surface of the catalyst.

Comparative Example 2 The ethylene/propylene molar ratio supplied to the reactor was 0.2
Co-dimerization of ethylene and propylene was carried out in the same manner as in Example 1 except that. The reaction results are shown in Table 1.

Compared to Example 1, more 4-methyl-1-pentene was produced as a by-product, and the selection rate for the target 1-pentene was significantly lowered.

Comparative Example 3 Co-dimerization of ethylene and propylene was carried out in the same manner as in Example 1 except that the reaction temperature was 150°C. The reaction results are shown in Table 1.

Compared to Example 1, the by-product of 4-methyl-1-pentene is very large, and the by-product of 2-pentene is also large.

As a result, the selectivity of the target 1-pentene is extremely low.

Comparative Example 4 Co-dimerization of ethylene and propylene was carried out in the same manner as in Example 1 except that the reaction temperature was 70°C. The reaction results are shown in Table 1.

Compared to Example 1, the ethylene conversion rate is extremely low.

Claims (2)

[Claims] (1) In a method for producing 1-pentene by co-dimerizing ethylene and propylene in a fixed bed method in the presence of a catalyst, (A) the catalyst comprises an alkali metal formed of anhydrous potassium carbonate and carbon. A catalyst supported on a compression-molded granular carrier, wherein (a) the alkali metal is composed of 20 to 90 g at % of sodium and 80 to 10 g at % of potassium, and (b) the compression-molded granular carrier is anhydrous potassium carbonate. contains 0.6 to 3% by weight of carbon, and 22 to 38% by weight of carbon.
% pore volume ratio and a compressive strength of 1.5 to 15 kg/cm^2G; have,
Further, the particle size distribution is such that the powder with a particle size of less than 100 μm is in the range of 1 to 15% by weight, the powder with a particle size of more than 600 μm is in the range of 1 to 20% by weight, and further, the bulk density is 0. 5
(B) Ethylene and propylene are supplied at an ethylene/propylene molar ratio of 0.30 to 0.95, and the pressure is 30 g/ml.
A method for producing 1-pentene by co-dimerization of ethylene and propylene, characterized in that the reaction is carried out at kg/cm^2 or more and at a temperature of 80 to 140°C. (2) The 1-pentene according to claim 1, wherein the anhydrous potassium carbonate constituting the carrier has a bulk density in the range of 0.53 to 0.69 g/ml as a raw powder before compression molding. manufacturing method.