JPH06287227A - Production of less branched olefinic low polymer - Google Patents

Abstract

PURPOSE:To obtain, in high yield, a 8C olefin having less side chains, useful as a raw material for plasticizers, and substantially not obtained by conventional methods by subjecting a low mol.wt. olefin fraction by-produced in petroleum refining, etc., and less valuable in its utilization to a low polymerization reaction. CONSTITUTION:A method for producing a less branched olefinic low polymer having 8 carbon atoms and <=1.5 branching degree in its side chains comprises polymerizing a normal 4C olefin as a main raw material at a reaction temperature of 50-200 deg.C under a reaction pressure of 20-100kg/cm<2>G at a LHSV of 0.1-5.0hr<-1> in the presence of a catalyst comprising a nickel oxide-carrying catalyst which is produced by impregnating a silica alumina carrier preliminarily heat-treated at a temperature of >=600 deg.C with a nickel salt solution and subsequently carrying nickel oxide in an amount of 3-15wt.% (expressed in terms of nickel) on the silica alumina.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an olefin low polymer having a small number of side chains, and more particularly to a method for producing a low branching C8 olefin low polymer useful as a raw material for producing a phthalic acid plasticizer. .

[0002]

2. Description of the Related Art Conventionally, a technique for oligomerizing an olefin by using a silica-alumina catalyst supporting nickel has been disclosed, for example, in JP-A-60-143830. Such a method has been proposed.

The technique disclosed in JP-A-60-143830 is a technique for oligomerizing an olefin using a catalyst in which Ni ⁺² cation is introduced into silica-alumina by cation exchange, and has been proposed so far. The aim is to improve the degree of branching and the catalytic activity of the product, which was insufficient by the oligomerization of olefins with the silica-alumina catalyst supporting nickel oxide.

By the way, diisononyl phthalate (DISP) as a plasticizer is octene (C8 olefin).
It is produced by oxo oxidation, esterification, etc. using as a raw material, but it is desired that the plasticizer in the usage form has low volatility in order to prevent curing of the resin,
Therefore, in order to reduce the amount of volatilization, octene as a raw material of a plasticizer is required to have a low branching degree with a small number of side chains.

In the technique disclosed in JP-A-60-143830, for example, a product (dimer or octene) obtained by using 2-butene as a raw material in the Examples has a branching degree of 1.59. In comparison with the case of using a silica-alumina catalyst supporting nickel oxide (the branching degree shown in the comparative example is 1.76), the branching degree is improved. According to their findings,
Octene obtained by this method is not always sufficiently satisfactory as a raw material for a plasticizer having the above-mentioned characteristics.

The present invention has been made in view of the above-mentioned prior art, and it is difficult to obtain by the prior art by low polymerization of a low molecular weight olefin fraction of relatively low utility value generated in petroleum refining and the like. Another object of the present invention is to provide a C8 olefin having a small number of side chains, which is useful as a plasticizer raw material, in a high yield.

[0007]

Means for Solving the Problems As a result of earnest studies on the method of further improving the added value of the olefin having a relatively low utility value of 4 carbon, which is generated from oil refining, etc. By using a treated catalyst and carrying out a low polymerization reaction under specific conditions, it is possible to obtain a C8 olefin low polymer having a reduced amount of side chains, which is useful as a plasticizer raw material. The present invention has been completed and the present invention has been completed.

That is, the method for producing a low-branched olefin low-polymerization product of the present invention uses, as a main raw material, an olefin having a normal structure and a C4 main component, and heat-treats it at a temperature of 600 ° C. or higher in advance as a catalyst. Using a nickel oxide-supported catalyst obtained by impregnating a silica / alumina carrier after the impregnation with a nickel salt solution and supporting 3 to 15% by weight of nickel oxide in terms of nickel amount, a reaction temperature of 50 to 200 ° C. and a reaction pressure of 50 ° C. 20-100kg / cm ² G, LH
Characterized by carrying out a polymerization reaction under the condition of SV 0.1 to 5.0 hr ^-1 to obtain an olefin low polymer having 8 carbon atoms in which the side chain of the reaction product has a branching degree of 1.5 or less. Is.

The method of the present invention will be described in more detail below.

In the present invention, silica.
A nickel oxide-supported catalyst in which nickel oxide is supported on an alumina carrier is used. The silica / alumina carrier has an alumina content of 10 to 90% by weight and a surface area of 50.
Amorphous silica-alumina having a pore size of ˜600 m ² / g and an average pore size of 10 to 100 Å can be preferably used. Particularly in the present invention, it is necessary that this carrier is impregnated with a nickel salt solution, and is then subjected to firing or the like to be supported on the structure of nickel oxide. However, the silica / alumina carrier is impregnated with the nickel salt solution. Prior to this, it is important to subject the carrier to a specific treatment of preliminarily performing heat treatment at a temperature of 600 ° C. or higher. By using a catalyst which has undergone such heat treatment, the product C8 olefin reduction is reduced. It is possible to reduce the side chain of the polymer to a desired value. This heat treatment is 600-1000 ° C
It is energy-efficient or economically preferable to carry out at this temperature. If the heat treatment is performed at less than 600 ° C, it becomes difficult to obtain the desired effect.

The amount of nickel oxide supported is preferably 3 to 10% by weight in terms of nickel amount. When the supported amount of nickel oxide is out of this range, it is disadvantageous in that the effect of reducing the side chain of C8 olefin of the product intended by the present invention is obtained, and the yield of C8 olefin is lowered, which is preferable. Absent.

The silica-alumina carrier which has been subjected to the above-mentioned specific treatment is impregnated with a nickel salt solution. As the impregnating agent, a nickel salt solution such as nickel nitrate, nickel chloride, nickel sulfate or nickel ammonium complex salt is used. it can.

As the impregnation method, an aqueous solution of nickel nitrate corresponding to the water absorption capacity of the carrier is prepared, and the solution is dropped little by little onto the carrier and impregnated and supported so that the surface of the carrier is uniformly wet. At this time, the concentration of the metal salt solution is adjusted so that the amount of nickel supported becomes 3 to 15% by weight. The catalyst thus impregnated with nickel is dried in air or vacuum at 90 to 110 ° C. At this time, in order to maintain the degree of dispersion of nickel so that the adsorbed nickel particles do not aggregate and become large, it is important to raise the temperature slowly and dry at a low temperature.

Next, the dried catalyst is preferably further calcined in an air stream at 400 to 600 ° C.

The nickel oxide-supported catalyst prepared in this manner is preferably dried before use in the low polymerization reaction at a temperature of 200 ° C. or higher in order to exert its function as a catalyst.

As the raw material olefin used in the present invention,
Although C4 olefins are mainly used, the present invention can be carried out even if other olefins are contained in addition to the C4 olefins, and the use of such a mixture is also included in the embodiments of the present invention. This C4 olefin is
Normal structure content is 90% or more, more preferably 95
% Of olefin is used. There is no particular limitation on the olefin concentration in the raw material and the isomer of the normal olefin structure. This olefin raw material is FCC
It is possible to use the butene fraction generated from the equipment or the residual butene fraction obtained by removing butadiene from the butene fraction generated from the ethylene cracker equipment, but it is essential that the butene fraction is enriched in normal butene except isobutene. Is.

The reaction conditions for carrying out the low polymerization reaction using this nickel oxide-supported catalyst are:
200 ℃, reaction pressure 20-100kg / cm ² G, LHS
V (liquid space velocity) is preferably in the range of 0.1 to 5.0 hours,
By appropriately selecting the reaction conditions within this range, it is possible to adjust the yield of the low polymerized product, the ratio of the amount of the dimer to the tetramer produced, and the degree of branching to an optimum value. An olefin low polymer having a certain degree of branching can be obtained. Therefore, if the reaction conditions deviate from the above range, it becomes difficult to obtain a predetermined effect.

The olefin low polymer according to the present invention can be obtained as a di- to tetramer product. Particularly, the dimer is selectively produced, and the olefin low polymer produced has a small number of side chains. Further, with regard to the C8 olefin in which the produced olefin low-weight product is a dimer, the degree of branching showing the degree of the side chain structure can be 1.5 or less.

The branching degree described here indicates the number of chain hydrocarbons (methyl group, ethyl group, etc.) branched from a main chain hydrocarbon having an aliphatic olefin structure, for example, a butene dimer having 8 carbon atoms. In terms of olefin, normal octene has a branching degree of 0, methylheptene has a branching degree of 1, dimethylhexene has a branching degree of 2, and trimethylpentene has a branching degree of 3. The above-mentioned branching degree of 1.5 or less means the average branching degree of these mixed olefins.

[0020]

INDUSTRIAL APPLICABILITY In the present invention, since a nickel oxide-supported catalyst which has been subjected to a specific treatment is used and a low polymerization reaction is carried out under a specific condition, a side chain amount useful as a plasticizer raw material is obtained. It is possible to obtain a C8 olefin low polymerized product in which the reduction of

[0021]

Example 1 Alumina content 29% by weight, surface area 439 m ² / g, pore volume 1.09 cm ³ / g, and an amorphous silica-alumina carrier preheated at a temperature of 600 ° C. with nickel nitrate. The amount of nickel was adjusted to 7 by the pore filling method using an aqueous solution.
%, And dried and then air-baked at 500 ° C. to prepare a nickel oxide-supported catalyst.

A fixed bed flow reactor was used for the reaction, 500 ml of the prepared catalyst was charged into a reactor, and a normal butene fraction having the properties shown in Table 1 was added under the reaction conditions shown in Table 2 at 500 ml / hr. The reaction was carried out at a flow rate. The resulting olefin conversion rate and the degree of branching of the octene fraction, which is the main product, are shown in Table 2. Example 2 The amorphous silica / alumina carrier used in Example 1 was heat-treated at a temperature of 800 ° C. before impregnation with nickel, and
A nickel oxide-supported catalyst was prepared and polymerized under the same conditions as in Example 1 except that the amount of nickel supported was 5%. The reaction conditions and results at this time are shown in Table 2. Example 3 In the same manner as in Example 1, using a nickel oxide-supported catalyst prepared so that the amount of nickel was 5%, the same stock oil as in Example 1 was polymerized under the reaction conditions shown in Table 2. The results are shown in Table 2. Comparative Example 1 Using the same raw material oil as in Example 1, the amorphous silica / alumina carrier heat-treated at 600 ° C. was used as it was as a catalyst without supporting a metal, and the same polymerization reaction as in Example 1 was carried out. When the reaction temperature was 80 ° C, almost no butene polymerization reaction was observed. The reaction conditions and results at this time are shown in Table 3. Comparative Example 2 The polymerization reaction was performed under the same conditions as in Example 2 except that the heat treatment temperature before impregnating the amorphous silica / alumina carrier having an alumina content of 29% by weight with the nickel nitrate solution was 500 ° C.

The results are shown in Table 3, and the product C
The branching degree of 8 olefins was 1.58.

As shown in Table 3, the degree of branching of the C8 olefin obtained in this Comparative Example is higher than those in Examples 1 and 2, and the silica / alumina carrier in the present invention is impregnated with the nickel salt solution. It was confirmed that the effect of using a nickel oxide-supported catalyst obtained by preliminarily heat-treating at 600 ° C. or higher was used. Comparative Example 3 Using the same nickel oxide-supported catalyst as in Example 3, an isobutene-normal butene fraction having the properties shown in Table 1 was reacted as a feed oil under the conditions shown in Table 4. Also in this result, the degree of branching of the obtained C8 olefin was higher than that in the Examples, and the influence of the content of isobutene as the feedstock in the present invention was shown. Comparative Example 4 The same raw oil as in Example 3 and the nickel oxide-supported catalyst were used and tested under the reaction conditions shown in Table 4. The results are shown in the same table. It was shown that increasing the reaction temperature too much increased the reactivity but affected the degree of branching of the product.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

Claims (1)

[Claims] 1. A main component is an olefin having a normal structure and a carbon number of 4, and a silica / alumina carrier, which has been previously heat-treated at a temperature of 600 ° C. or higher, is impregnated with a nickel salt solution as a catalyst, and Using a nickel oxide-supported catalyst supporting nickel oxide in an amount of 3 to 15% by weight in terms of nickel, at a reaction temperature of 50 to 200.
C, reaction pressure 20-100 kg / cm ² G, LHSV 0.1
By carrying out the polymerization reaction under the condition of 5.0 hr ^-1 , the side chain of the reaction product has a branching degree of 1.5 or less and a carbon number of 8
The method for producing a low-branched olefin low-polymerized product, comprising: