JPH08133992A - Production of 1-pentene - Google Patents

Abstract

PURPOSE: To provide a method for producing 1-pentene by which the reactional selectivity can be improved and the 1-pentene can efficiently be produced by using a catalyst having a high activity even at low temperatures. CONSTITUTION: This method for producing 1-pentene is to bring a catalyst prepared by supporting an alkali metal on a compression molded granular carrier comprising an anhydrous potassium compound and carbon into contact with propylene at 130-170 deg.C temperature under >=20kg/cm<2> G pressure and then carry out the codimerization, in the method for producing the 1-pentene by codimerizing ethylene with propylene in the presence of the catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing 1-pentene useful as a raw material for polyolefin. More specifically, the present invention relates to a method for producing 1-pentene using a catalyst having excellent low temperature activity and reaction selectivity.

[0002]

2. Description of the Related Art Conventionally, a method for producing 1-pentene by co-dimerizing ethylene and propylene using a catalyst in which an alkali metal is supported on a support is described in, for example, Chem. Brit. vol.5, 354 (1969). However, the conventional methods using a catalyst have drawbacks in catalytic activity and reaction selectivity, and improvement thereof has been desired.

In the production of 1-pentene on an industrial scale, it is advantageous to use a granular carrier as a support. As such a catalyst, a catalyst in which metallic potassium and stainless steel powder are carried on a potassium carbonate granular carrier is disclosed. It is disclosed in Japanese Patent Publication No. 61-46248. However, the 1-pentene selectivity obtained by the co-dimerization reaction of ethylene and propylene using this catalyst was as low as 77 to 82%, and required a high temperature reaction of 135 ° C or higher.

Japanese Unexamined Patent Publication No. 3127/1993 discloses a catalyst in which metallic potassium and stainless steel powder are supported on an extruded potassium carbonate carrier. However, this catalyst also has a poor reaction selectivity, and only 1-pentene selectivity of 37 to 84% is obtained. The reaction temperature must be as high as 140 ° C or higher.

A catalyst in which sodium metal is supported on a compression-molded granular carrier composed of potassium carbonate and carbon is disclosed in Japanese Patent Laid-Open No. 3-41036.
No. 6,086,045. Although the co-dimerization reaction of ethylene and propylene using this catalyst can be performed at a relatively low temperature, the 1-pentene selectivity is 90.7-93.2%, which is not yet sufficiently high.

[0006]

The object of the present invention is to provide a method for efficiently producing 1-pentene which can improve the 1-pentene selectivity in the co-dimerization of ethylene and propylene and which has a high activity even at a low temperature. To do.

[0007]

[Means for Solving the Problems] The present invention provides a method in which ethylene and propylene are co-dimerized in the presence of a catalyst obtained by supporting an alkali metal on a compression-molded granular carrier composed of an anhydrous potassium compound and carbon. -In the method for producing pentene, the method for producing 1-pentene, characterized in that the catalyst is brought into contact with propylene at a temperature of 130 to 170 ° C and a pressure of 20 kg / cm ² G or more and then codimerization is carried out. .

In the present invention, potassium carbonate and potassium fluoride are preferable as the anhydrous potassium compound. Although each may be used alone, it is preferable to mix and use potassium carbonate and potassium fluoride because the co-dimerization reaction selectivity is increased and the activity improving effect by propylene contact is also increased. As the anhydrous potassium compound, potassium halide such as potassium chloride, potassium bromide, potassium iodide, potassium sulfate, potassium nitrate, potassium silicate, potassium silicofluoride, etc. may be contained in addition to potassium carbonate and potassium fluoride.

Specific examples of the alkali metal used in the present invention include sodium, potassium and a mixture thereof. Generally, the reaction activity of sodium metal is considerably lower than that of potassium metal. However, when the sodium metal is brought into contact with potassium fluoride or potassium carbonate under heating, the sodium metal easily undergoes an exchange reaction to form sodium fluoride or sodium carbonate and potassium metal. It is also possible to use sodium metal alone as the metal component. In particular, in the present invention, the catalyst using sodium has a remarkable effect of improving the selectivity.

The amount of the alkali metal used is not particularly limited, but is preferably 1 to 10% by weight based on the total weight of the catalyst.
1.5 to 6% by weight is preferred. Generally, increasing the amount of the alkali metal supported increases the production rate per unit weight of the catalyst, which is industrially advantageous, but it is difficult to remove heat even if the amount is excessively increased, or the selectivity decreases. It is not preferable.

The carbon used in the present invention is activated carbon,
Examples include graphite and carbon black. These may be used alone or in a mixture of two or more. Particularly, graphite can be preferably used.

In the present invention, the amount of carbon used is not particularly limited, but is preferably 0.2 to 3.0% by weight based on the total weight of the catalyst.

In the present invention, carbon and an anhydrous potassium compound raw powder are sufficiently mixed, and the mixed raw powder is compressed into a tablet molding machine,
The carrier can be produced by compression molding with a compression molding machine, pelletizer, or the like.

Anhydrous potassium compound is used as a mixed raw powder before compression molding and has a loose packing bulk density of 0.6 g / carbon-free state.
If it goes below ml, the flow will become poor and compression molding will not be possible. If it exceeds 1.2 g / ml, molding is easy,
The obtained granular carrier becomes dense with a small specific surface area. The potassium fluoride and potassium carbonate raw powders may be used as they are as they are, or they may be pulverized or granulated and then mixed. Alternatively, it may be pulverized after mixing.

The shape of the compression-molded granular carrier is not particularly limited, but it is usually cylindrical, pelletized, spherical, etc., and the particle size is usually 0.5 mm or more, preferably 1-10.
The range is mm. The strength of the carrier is not particularly limited, but may be in the range of 1.5 to 20 kg (radial crushing strength).

The carrier must be dried before supporting the alkali metal. Dry under reduced pressure at 50-200 ℃ or 200-600 ℃
It is preferable to perform normal pressure firing. Only vacuum drying,
Only normal pressure firing or both may be performed.

The method of loading the alkali metal on the carrier is, for example, by stirring and mixing the dried or calcined carrier at a temperature above the melting point of the alkali metal, preferably at a temperature of 200 to 450 ° C. under an inert gas atmosphere. It can be carried out. The catalyst of the present invention does not show a significant decrease in crush strength even by the above-mentioned alkali metal supporting treatment, and can be effectively used as a practical catalyst.

In the present invention, the above catalyst is treated with propylene before the codimerization reaction. By this treatment, the co-dimerization activity of the catalyst is greatly improved as compared with the untreated one.
Since the space-time yield (STY) is increased and the reaction can be performed at a lower temperature, the reaction selectivity is improved and the catalyst life is extended.

The temperature of the contact treatment with propylene is higher than that in the co-dimerization reaction, specifically 130 to 170 ° C. The temperature is preferably 135 to 160 ° C, more preferably 140 to 155 ° C. If it is less than the above range, the improvement of the co-dimerization activity is not sufficient. If the amount exceeds the above range, the deactivation of the catalyst starts during the treatment, and similarly, a high co-dimerization activity cannot be obtained.

The propylene pressure at the time of contact is 20 kg / cm ² G or more, preferably 30 kg / cm ² G or more. Below the above pressure, the improvement of co-dimerization activity is not sufficient. The upper limit of the propylene pressure is not particularly limited, but is 150 kg / cm ² G from a practical viewpoint. The time required for the propylene treatment is not particularly limited as it is shortened as the contact temperature and pressure are higher, but it is practically in the range of 2 to 50 hours.

According to the method of the present invention, in the presence of the catalyst obtained as described above, a fixed bed system is preferably used as a reaction system, and ethylene and propylene are co-dimerized to give 1-pentene. To manufacture.

The reaction pressure is preferably 20 kg / cm ² G or more,
More preferably, it is in the range of 30 to 150 kg / cm ² G or more. If the reaction pressure is less than 20 kg / cm ² G, the space-time yield will be small. The upper limit of the reaction pressure is not particularly limited, but is 150 kg / cm ² G from a practical viewpoint.

The reaction temperature is preferably in the range of 90 to 130 ° C, more preferably in the range of 95 to 125 ° C. When the reaction temperature is lower than 90 ° C, the space-time yield becomes small. Also, 1
If it exceeds 30 ° C, the 1-pentene selectivity is lowered and the space-time yield (STY) becomes too large, so that it becomes difficult to remove heat from the reaction tube.

Liquid hourly space velocity of ethylene and propylene (LH
SV) is usually 0.5 to 10 hr ^-1 , preferably 1 to 7 hr ^-1.
Range.

[0025]

INDUSTRIAL APPLICABILITY According to the present invention, in the co-dimerization of ethylene and propylene, by carrying out the co-dimerization after contacting the catalyst with propylene, it is possible to obtain high reaction selectivity with increased low-temperature activity. -Provided a method for manufacturing penten.

[0026]

Embodiments of the present invention will be described below.

Example 1 50 parts by weight of potassium fluoride powder having an average particle diameter of 270 μm, a loosely packed bulk density of 1.148 g / ml and a BET specific surface area of 0.09 m ² / g,
Average particle size 250μm, bulk density 0.953g / ml, specific surface area 0.84
After mixing with 50 parts by weight of m ² / g potassium carbonate powder, the mixture was pulverized with a Willey pulverizer (500 μm screen). After adding 0.99% by weight of graphite powder to this pulverized raw powder and mixing them well, they were tablet-molded into a cylindrical carrier having a diameter of 3 mm and a height of 3 mm. The crushing strength (radial direction) measured using a Kiya hardness meter was 4.6 kg. After vacuum drying at 100 ° C for 20 hours,
2.50% by weight metallic sodium was added under a nitrogen atmosphere.
A catalyst was prepared by stirring at 70 ° C. for 4 hours. 64.88 g of this catalyst was filled in a tubular reactor having a catalyst volume of 54 ml and an inner diameter of 21 mm, and propylene was supplied at a liquid space velocity (LHSV) of 5.18 hr ^-1 at a reaction pressure of 100 kg / cm ² G and a temperature of 150 ° C for 14 hr. Was pretreated. Then, the temperature and pressure were reduced to 105 ° C and 50 kg / cm ² G, and a mixed gas of ethylene and propylene was supplied at a LHSV of 4.40 hr ^-1 at an ethylene / propylene molar ratio of 0.56 to carry out a continuous flow reaction. . The conversion rate of ethylene is 12.8%, 1-
The penten selectivity was 94.7%. The propylene pretreatment conditions, reaction conditions and reaction results are shown in Table 1, Table 2 and Table 3, respectively.

Example 2 Co-dimerization of ethylene and propylene was carried out in the same manner as in Example 1 except that the catalyst loading was 63.54 g and the propylene pretreatment time was 6 hr. The propylene pretreatment conditions, reaction conditions and reaction results are shown in Table 1, Table 2 and Table 3, respectively.

Example 3 Codimerization of ethylene and propylene was carried out in the same manner as in Example 2 except that the reaction temperature was changed. The propylene pretreatment conditions, reaction conditions and reaction results are shown in Table 1, Table 2 and Table 3, respectively.

Comparative Example 1 0.99 wt% was added to the ground raw powder prepared in the same manner as in Example 1.
The graphite powder and 0.20% by weight of activated carbon were added and the mixture was tablet-molded. The crush strength was 3.4 kg. After drying under reduced pressure at 100 ° C for 18 hours, 2.51% by weight of metallic sodium was added in a nitrogen atmosphere, and the mixture was stirred at 370 ° C for 4 hours to prepare a catalyst. 59.71 g of this catalyst was charged into the tubular reactor described in Example 1 and the temperature was
Under the conditions of a pressure of 105 ° C. and 55 kg / cm ² G, a mixed gas of ethylene and propylene was fed at an LHSV of 4.27 hr ⁻¹ at an ethylene / propylene molar ratio of 0.60 to carry out a continuous flow reaction. The propylene pretreatment conditions, reaction conditions and reaction results are
The results are shown in Table 1, Table 2 and Table 3, respectively.

Comparative Example 2 Codimerization of ethylene and propylene was carried out in the same manner as in Comparative Example 1 except that the reaction temperature was changed. The propylene pretreatment conditions, reaction conditions and reaction results are shown in Table 1, Table 2 and Table 3, respectively.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

Claims (1)

[Claims] 1. Ethylene and propylene are co-dimerized in the presence of a catalyst prepared by supporting an alkali metal on a compression-molded granular carrier composed of an anhydrous potassium compound and carbon, to obtain 1-
In a method for producing pentene, the catalyst is added to 130-170.
A method for producing 1-pentene, which comprises contacting with propylene at a temperature of ℃ and a pressure of 20 kg / cm ² G or more and then performing co-dimerization.