JP2607007B2 - Method for producing olefin oligomer - Google Patents

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 oligomer, and more particularly to a method for producing a catalyst component, boron trifluoride, from a polymerization product containing an olefin oligomer with high purity.
The present invention relates to a method for producing an olefin oligomer which can be recovered at a high recovery rate.

[0002]

2. Description of the Prior Art Oligomers of olefins having 6 to 14 carbon atoms are mainly used as synthetic lubricating base oils. In particular, linear α-olefins having 10 carbon atoms, ie, oligomers of 1-decene, particularly oligomers containing a trimer of 1-decene as a main component, have excellent performance as lubricating oils. Methods are being actively developed.

Heretofore, as a method for producing this olefin oligomer, a complex of boron trifluoride and a co-catalyst and a catalyst comprising boron trifluoride have been used in the presence of a catalyst having 6 to 14 carbon atoms.
A method for polymerizing olefins is known. In this method, a polymerization product containing an olefin oligomer is neutralized with alkaline water or the like after polymerization to deactivate a catalyst contained therein, and the catalyst is not usually recovered. For this reason, there has been a problem of post-polymerization treatment that a large amount of waste containing a fluorine compound and a boron compound is generated and must be treated.

Various methods have been tried so far for recovering a catalyst contained in a polymerization product containing an olefin oligomer. For example, a method in which one of the catalyst components of the complex of boron trifluoride and co-catalyst or boron trifluoride constituting the catalyst is separated first, and then the other catalyst component is separated in two steps (hereinafter referred to as this method). The method (conventional method (A)) is disclosed in JP-A-2-1086.
No. 38 discloses this. In this conventional method (A), either one of the components is first separated to reduce the activity of the catalyst, so that the polymerization is unlikely to occur during the catalyst recovery treatment, and the olefin oligomer, which is the target product, is less likely to deteriorate. There is. However, since the complex of boron trifluoride and the co-catalyst is altered during the recovery treatment and the catalytic activity of the complex is reduced, there is a problem in reusing the recovered complex as it is for the polymerization of olefins. There is also a problem that a complicated device is required for recovery.

[0005] JP-A-2-1088638 discloses that
As a method other than the conventional method (A), the polymerization product is heated to a temperature equal to or higher than the decomposition temperature of the complex composed of boron trifluoride and the cocatalyst, and the complex is decomposed into boron trifluoride and the cocatalyst; A method of recovering boron trifluoride generated by decomposition of the complex together with boron trifluoride present in the product (hereinafter, this method is referred to as a conventional method (B)) is also disclosed. This conventional method (B) has the advantage that no complicated apparatus is required for recovery. However, there is a problem that the composition of the obtained olefin oligomer is liable to change due to further polymerization of the olefin oligomer in the polymerization product during the recovery treatment of boron trifluoride. In addition, the decomposition of boron trifluoride and the purity of the recovered boron trifluoride are reduced, so that there is also a problem that it is difficult to reuse the olefin polymerization catalyst as it is.

Accordingly, an object of the present invention is to eliminate the drawbacks of the above-mentioned conventional methods, particularly the conventional method (B), and to obtain boron trifluoride as a catalyst component from a polymerization product containing an olefin oligomer with high purity and high recovery. Another object of the present invention is to provide a method for producing an olefin oligomer which can be recovered without changing the composition of the olefin oligomer.

[0007]

Means for Solving the Problems The present inventors have conducted various studies to achieve the above object, and as a result, the change in the composition of the olefin oligomer in the conventional method (B) was found to be caused by boron trifluoride and a co-catalyst. Was found to occur mainly in the process of raising the temperature of the polymerization product to a predetermined temperature in order to decompose the complex consisting of, and that after reaching this predetermined temperature, there was almost no change in the olefin oligomer composition. .
Further, the present inventors, by heating the polymerization product immediately after the polymerization reaction to a temperature of 110 to 155 ° C.,
It has been found that a change in the olefin oligomer composition can be suppressed, and that boron trifluoride can be recovered efficiently.

The present invention has been completed based on these findings, and is intended to polymerize an olefin having 6 to 14 carbon atoms in the presence of a complex of boron trifluoride and a co-catalyst and a catalyst comprising boron trifluoride. As a result, a polymerization product containing an olefin oligomer is obtained.
A gist of the present invention is a method for producing an olefin oligomer, which comprises heating and holding at a temperature of about 155 ° C. and separating and recovering boron trifluoride from the polymerization product.

Hereinafter, the present invention will be described in detail. The method for producing an olefin oligomer of the present invention includes, as main steps, an olefin oligomer polymerization step and a boron trifluoride recovery step. Therefore, the polymerization step will be described first, and then the boron trifluoride recovery step will be described.

As the starting monomer for the polymerization step , an olefin having 6 to 14 carbon atoms, that is, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene or tetradecene is used. These may be either an α-olefin having a double bond at the terminal of the carbon chain or an internal olefin having a double bond inside the carbon chain.
It is preferably an olefin, particularly preferably a linear α-olefin having 10 carbon atoms, ie, 1-decene.

The catalyst used comprises a complex of boron trifluoride and co-catalyst and boron trifluoride. Examples of the promoter include the following. Water Alcohol: methanol, ethanol, n-butanol, decanol Carboxylic acid: acetic acid, propionic acid, butyric acid ether: dimethyl ether, diethyl ether Acid anhydride: acetic anhydride, succinic anhydride ester: ethyl acetate, methyl propionate ketone: acetone, methyl ethyl ketone Aldehyde: acetaldehyde, benzaldehyde These cocatalysts can be used alone or in combination of two or more. As co-catalyst, n-butanol is particularly preferred.

The amount of the complex of boron trifluoride and co-catalyst is usually 0.05 to 10.0% by volume, preferably 0.1 to 5.0% by volume, based on the olefin. Boron trifluoride may be present in a trace amount in the polymerization reaction system, and is usually 0.01 to 2 times, preferably 0.1 to 1.5 times, the saturation concentration of the olefin oligomer at normal pressure. . At the beginning of the reaction, the concentration of boron trifluoride is preferably lower than the saturation concentration of the olefin oligomer at normal pressure in order to suppress the calorific value. In the latter half of the reaction, the concentration of boron trifluoride is preferably higher than the saturation concentration of the olefin oligomer at normal pressure to promote the reaction.

The polymerization temperature is usually -20 to 90 ° C, preferably 0 to 50 ° C. The polymerization pressure is usually 0 to 35 kg.
/ Cm ² G, preferably 0.05 to 5 kg / cm ² G. The polymerization time is generally 0.25 to 24 hours, preferably 2 to 16 hours. As the polymerization method, any of a batch method and a continuous method can be adopted. Usually, boron trifluoride is continuously supplied into the polymerization reaction system during the polymerization reaction.

Step of recovering boron trifluoride In this step, boron trifluoride is separated from a polymerization product containing the olefin oligomer obtained in the polymerization step,
This is the step of collecting. In this step, separation and recovery of boron trifluoride are performed by heating and maintaining the polymerization product containing the olefin oligomer at a temperature of 110 to 155 ° C.

The reason why the heating temperature is limited to the range of 110 to 155 ° C. is as follows. Heating temperature is 110 ° C
If it is less than 3, the complex of boron trifluoride and the co-catalyst does not decompose, or the decomposition rate is low, not only the recovery rate of boron trifluoride drops sharply, but the polymerization product further polymerizes, The composition of the product changes. On the other hand, as the heating temperature increases, the recovery rate of boron trifluoride increases. However, when the temperature exceeds 155 ° C., the recovery rate of boron trifluoride stays flat and hardly increases. The purity of boron boride decreases.

In order to avoid a change in the composition of the polymerization product, the temperature is preferably raised within a short time after the completion of the polymerization step.
Specifically, it is preferable to heat to a temperature of 110 to 155 ° C. within a time of 5 minutes or less. In particular, it is preferable that the heating to the above temperature be performed instantaneously. Such instantaneous heating
A method in which the polymerization product obtained in the polymerization step is introduced into a mixing tank equipped with a heating jacket and a stirrer, or the polymerization product obtained in the polymerization step is heated with a heat exchanger, and then the heating jacket is stirred. This can be easily achieved by introducing into a mixing tank equipped with a machine. In the latter method,
Since the polymerization product is heated in the heat exchanger, the use of a heating jacket and / or a stirrer can be omitted.

As described above, the step of recovering boron trifluoride is preferably performed by a continuous method in which the polymerization product can be heated in a short time, but may be performed by a batch method.

By heating and maintaining the polymerization product at the above-mentioned predetermined temperature, the complex of boron trifluoride and co-catalyst in the polymerization product is decomposed, and the boron trifluoride obtained by the decomposition is polymerized. It is discharged out of the system together with the boron trifluoride present in the product, collected and recycled for recycling. During this heating and holding period, the polymerization product does not further polymerize, so that its composition does not change, and the obtained olefin oligomer is preferably used as a synthetic lubricating base oil.

[0019]

The present invention will be further described with reference to the following examples.

Example 1 (i) Production of 1-decene oligomer As a polymerization apparatus, a continuous reaction apparatus in which four 1-liter complete mixing reactors were connected in series was used. In each tank, the pressure was controlled at normal pressure, the temperature was controlled at 20 ° C., and the residence time was controlled at 2 hours.
As the catalyst, a complex of boron trifluoride and n-butanol and boron trifluoride were used. 1-decene was supplied to the first tank at 400 ml / hr, and the complex was supplied at 1.6 ml / hr. Boron trifluoride was supplied to the first, second and third tanks. The amount of boron trifluoride supplied to each of these polymerization tanks was such that the concentration of boron trifluoride in 1-decene in the first tank was 0.2 to the saturation concentration of boron trifluoride in 1-decene at normal pressure. Times, 0.4 in the second tank
In the third tank, the supply amount of boron trifluoride was controlled to be 1.2 times. Table 1 shows the composition of the obtained 1-decene oligomer.

(Ii) Recovery of boron trifluoride As a device for recovery of boron trifluoride, a 50 ml three-necked flask equipped with a stirrer and a gas discharge tube was used. The gas discharge pipe was connected to a gas absorption bottle containing a 3% aqueous ammonia solution. 20 ml of the 1-decene oligomer obtained in the above (i) was placed in the three-necked flask, heated to 120 ° C. for 3 minutes with stirring in an oil bath, and maintained at a temperature of 120 ° C. for 30 minutes. The complex of boron fluoride and n-butanol was decomposed, and boron trifluoride was separated and recovered.

The recovery rate of boron trifluoride, the decomposition rate of boron trifluoride, and the purity of recovered boron trifluoride were determined as follows.

(A) Determination of Boron and Fluorine Heated Liquid After Heating A 3% aqueous ammonia solution is placed in a 50 ml three-necked flask, and the boron trifluoride remaining in the heated liquid and the boron trifluoride decomposition product Was extracted into the aqueous layer. This water layer was quantitatively analyzed for boron and fluorine. Liquid to be heated before heating As in the case of the liquid to be heated after heating, the amounts of boron and fluorine were determined in advance.

(B) Recovery rate of boron trifluoride The weight of boron trifluoride [W _BF3 (before heating)] of the liquid to be heated before heating (converted from the measured value) and the aqueous layer extracted from the liquid to be heated after heating Boron trifluoride weight [W _BF3 (after heating)]
(Converted from the measured value) and calculated (based on boron). Recovery rate (%) = (W _BF3 (before heating) −W _BF3 (after heating)) ÷ W _BF3 (before heating) × 100

(C) Decomposition rate of recovered boron trifluoride A recovery rate (fluorine-based recovery rate) obtained by calculating the amount of boron trifluoride from the result of quantitative analysis of fluorine and a result of quantitative analysis of boron, It was determined from the difference from the recovery rate obtained by calculating boron (boron-based recovery rate). Boron trifluoride decomposition rate = (fluorine-based recovery rate)-(boron-based recovery rate)

(D) Purity of Recovered Boron Trifluoride Gas discharged without being absorbed by the aqueous ammonia solution in the gas absorption bottle during heating was quantitatively analyzed and calculated (based on boron). Purity (%) = [W _BF3 (before heating)-W _BF3 (after heating)]
÷ [W _BF3 (before heating) −W _BF3 (after heating) + weight of exhaust gas] × 100 The obtained boron trifluoride recovery rate, boron trifluoride decomposition rate, and recovered boron trifluoride purity are shown in Table 1. . Table 1 also shows the composition and kinematic viscosity of the olefin oligomer before and after heating.

As is clear from Table 1, according to Example 1, the recovery of boron trifluoride was as high as 55%, and the purity of the recovered boron trifluoride was as high as 95%. The composition of the olefin oligomer was hardly changed before and after the heating, and the kinematic viscosity was hardly changed.

Example 2 (i) Production of 1-decene oligomer A 1-decene oligomer was produced under the same polymerization conditions as in Example 1. (Ii) Recovery of boron trifluoride Boron trifluoride was recovered in the same manner as in Example 1 except that the heating and holding time was set to 1 hour. Table 1 shows the results. As is clear from Table 1, good results were obtained as in Example 1.

Example 3 (i) Production of 1-decene oligomer Example 1 was repeated except that the polymerization temperature was 25 ° C. and the supply amount of the complex of boron trifluoride and n-butanol was 2.5 ml / hr. Under the same polymerization conditions as described above, a 1-decene oligomer was produced.

(Ii) Recovery of boron trifluoride Boron trifluoride was recovered in the same manner as in Example 1 except that the heating temperature was 140 ° C. and the holding time was 1 hour. Table 1 shows the results. As is clear from Table 1, good results were obtained as in Example 1.

Comparative Examples 1 and 2 (i) Production of 1-decene oligomer The same polymerization as in Example 1 was carried out except that the supply amount of the complex of boron trifluoride and n-butanol was 2.4 ml / hr. Under the conditions, a 1-decene oligomer was produced. (Ii) Recovery of boron trifluoride Boron trifluoride was recovered in the same manner as in Example 1 except that the heating temperature and the holding time (100 ° C., 1 hour or 60 ° C., 1 hour) described in Table 2 were used. Recovery was performed. Table 2 shows the results. Table 2 shows that the heating temperature was within the limited range (110
In the case of Comparative Example 1 (100 ° C.) and Comparative Example 2 (60 ° C.) below the lower limit of (−155 ° C.), the boron trifluoride recovery rate was found to be extremely low.

Comparative Examples 3 and 4 (i) Production of 1-decene oligomer A 1-decene oligomer was produced under the same polymerization conditions as in Example 1. (Ii) Recovery of boron trifluoride Example 1 except that the heating temperature and the holding time (160 ° C., 0.5 hours or 180 ° C., 0.5 hours) described in Table 2 were used.
As in the above, boron trifluoride was recovered. Table 2 shows the results. From Table 2, Comparative Example 3 (160) in which the heating temperature exceeds the upper limit of the limited range (110 to 155 ° C.) of the invention
C) and Comparative Example 4 (180 ° C.), the boron trifluoride recovery rate was high, but the purity of the recovered boron trifluoride was remarkably low (82% in Comparative Example 3).

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

As described above, according to the present invention, boron trifluoride as a catalyst component is converted from a polymerization product containing an olefin oligomer with high purity and a high recovery rate, and the composition of the polymerization product is changed. The present invention provides a method for producing an olefin oligomer which can be recovered without any problems.

Claims (1)

(57) [Claims] An olefin having 6 to 14 carbon atoms is polymerized in the presence of a complex of boron trifluoride and a co-catalyst and a catalyst comprising boron trifluoride to obtain a polymerization product containing an olefin oligomer. Immediately after heating, maintaining the polymerization product at a temperature of 110 to 155 ° C., and separating and recovering boron trifluoride from the polymerization product.