WO2016152355A1

WO2016152355A1 - Production method and production system for conjugated diene polymer

Info

Publication number: WO2016152355A1
Application number: PCT/JP2016/055035
Authority: WO
Inventors: 山下　博司; 誠野瀬; 純山下; 北村　隆
Original assignee: 宇部興産株式会社
Priority date: 2015-03-26
Filing date: 2016-02-22
Publication date: 2016-09-29
Also published as: KR101808476B1; JPWO2016152355A1; CN107614539A; KR20170104368A; CN107614539B; TWI615412B; MY176186A; TW201638114A; JP6015998B1

Abstract

The present invention is capable of recovering the yield rate when the yield rate gradually becomes lower during production of a conjugated diene polymer. The conjugated diene polymer is produced by using a transition metal catalyst, and an organoaluminum compound as a co-catalyst. The yield rate gradually becomes lower when successive production of the conjugated diene polymer is continued. In response, the supplied amount the co-catalyst is adjusted on the basis of the generation level of inactivate substances generated in the reaction system. Specifically, increasing the amount of the co-catalyst is started when the generation level becomes equal to or lower than a predetermined value. Furthermore, increasing the amount of the co-catalyst is stopped when determined that sufficient recovery has occurred. More specifically, supply of the predetermined amount that had been supplied before the amount was increased is started.

Description

Production method and production system of conjugated diene polymer

The present invention relates to a production method and production system of a conjugated diene polymer capable of recovering a reduced yield.

As a method for producing a conjugated diene polymer, a method of polymerizing a solution containing a conjugated diene monomer by adding a transition metal catalyst as a catalyst and an organoaluminum compound as a promoter is proposed (for example, Patent Document 1). And 2).

Specifically, a cobalt-based catalyst, a non-halogenated organoaluminum compound, and a halogenated organoaluminum compound are added to a monomer solution of 1,3-butadiene. Thereby, 1,4-polybutadiene is obtained.

JP 2013-209470 A JP 2013-227524 A

A high yield can be obtained by appropriately using a catalyst and a cocatalyst as described above.

However, there is a problem that the yield gradually decreases while the production of the conjugated diene polymer is continued in the plant.

The present invention has been made in view of the above problems, and provides a production method and production system of a conjugated diene polymer capable of recovering the yield when the yield is gradually reduced. Objective.

The inventors of the present invention have made the present invention as a result of earnestly examining the cause of the yield reduction and countermeasures.

The present invention is a method for producing a conjugated diene polymer, and in a conjugated diene polymerization reaction using an organoaluminum compound as a promoter,
The supply amount of the co-catalyst is adjusted based on the degree of generation of the deactivated material generated in the reaction system.

In the above invention, the polymerization activity index of the reaction is determined based on the degree of formation of the deactivated substance produced in the reaction system,
When the polymerization activity index falls below the first reference value, the cocatalyst is supplied in an increased amount compared to before the polymerization activity index falls below the first reference value.

In the above invention, when the polymerization activity index becomes equal to or higher than the second reference value by supplying the cocatalyst in an increased amount, the same amount of the catalyst activity index as before the polymerization activity index becomes equal to or lower than the first reference value. Supply co-catalyst.

In the above invention, the polymerization activity index when the deactivated substance is not formed is 100. The first reference value is set to 80% or more. The second reference value is set to 95% or more.

In the above invention, the organoaluminum compound has a halogen-containing organoaluminum compound and a halogen-free organoaluminum compound.

The present invention relates to a conjugated diene polymer production system for controlling a conjugated diene polymerization reaction using an organoaluminum compound as a co-catalyst, and a detection unit for detecting the generation degree of a deactivated substance generated in the reaction system; And a promoter supply amount adjusting unit that adjusts the supply amount of the promoter based on the detected value.

In the method and system for producing a conjugated diene polymer of the present invention, the yield can be recovered when the yield gradually decreases.

It is a conceptual diagram of the manufacturing system of a conjugated diene polymer. It is a figure which shows the relationship between the catalyst deactivation substance generation amount calculated | required based on experimental data, and a polymerization activity index. It is a figure which shows the operation | movement history assumed. It is a figure explaining the result when this invention is applied to a real machine. It is a functional block diagram concerning a control system.

<Overview>
In the present invention, a conjugated diene polymer is produced using a transition metal catalyst and an organoaluminum compound as a promoter. At that time, the supply amount of the cocatalyst is adjusted based on the degree of generation of the deactivated material generated in the reaction system. Specifically, the cocatalyst increase is started at an appropriate timing, and the cocatalyst increase is stopped at an appropriate timing. Details will be described as follows.

<Diene monomer>
In the present embodiment, examples of the diene monomer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, and the like. These may be used singly or in combination of two or more, and may be used by copolymerizing with other dienes such as 1,3-hexadiene. Of these, 1,3-butadiene is preferred.

The concentration of the conjugated diene monomer in the monomer solution is preferably in the range of 10 to 90% by weight, more preferably in the range of 20 to 70% by weight, and still more preferably in the range of 25 to 50% by weight.

For example, 1,4-polybutadiene can be obtained by performing cis-1,4 polymerization using 1,3-butadiene as a conjugated diene monomer.

<Transition metal catalyst>
Examples of transition metal catalysts include cobalt-based catalysts, nickel-based catalysts, neodymium-based catalysts, vanadium-based catalysts, and titanium-based catalysts. Among these, a cobalt catalyst or a nickel catalyst is preferable, and a cobalt catalyst is more preferable. A transition metal catalyst may be used individually by 1 type, and may be used in combination of 2 or more type.

Cobalt catalysts include cobalt halide salts such as cobalt chloride and cobalt bromide; inorganic acid cobalt salts such as cobalt sulfate and cobalt nitrate; cobalt octaate, cobalt octylate, cobalt naphthenate, cobalt acetate, cobalt malonate, etc. And cobalt complexes such as bisacetylacetonate cobalt, trisacetylacetonate cobalt, acetoacetic acid ethyl ester cobalt, cobalt salt pyridine complex, cobalt salt picoline complex, and cobalt salt ethyl alcohol complex. Of these, cobalt octaate is preferable.

The amount of the cobalt-based catalyst added is usually preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻⁴ mol of the cobalt-based catalyst with ^respect to 1 mol of the diene monomer, and preferably 1 × 10 ⁻⁶ to 1 × 10 ⁻⁵ mol. Particularly preferred.

<Organic aluminum promoter>
An organoaluminum cocatalyst is used with a transition metal catalyst. The addition amount of the organoaluminum cocatalyst is preferably in the range of 50 to 2000 mol per 1 mol of the transition metal catalyst.

In particular, in the present embodiment, an organoaluminum compound containing halogen and an organoaluminum compound not containing halogen are used in combination.

Examples of non-halogenated organoaluminum compounds include organoaluminum hydrides such as trialkylaluminum, dialkylaluminum hydride, and alkylaluminum sesquihydride. Trialkylaluminum is preferred, and triethylaluminum (TEA) is more preferred.

Examples of the halogenated organoaluminum include dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum dichloride, alkylaluminum dibromide, alkylaluminum sesquichloride, and alkylaluminum sesquibromide. Of these, organoaluminum chloride is preferable, and diethylaluminum chloride (DEAC) is more preferable.

The molar ratio of the halogenated organoaluminum / non-halogenated organoaluminum compound is preferably 1 to 5, and more preferably 2 to 4.

<Deactivated material and degree of generation of deactivated material>
When a cobalt-based catalyst and an organoaluminum cocatalyst are added to the butadiene monomer solution and polymerized, 4-vinyl-1-cyclohexene (4-VCH) is generated as a deactivated substance (poisoned substance). The amount of the deactivated substance generated is measured by gas chromatography (GC) as needed from the start of polymerization.

As a deactivation material production index, the molar ratio of deactivation material generation amount / organic aluminum halide supply amount is used. For example, a 4-VCH / DEAC molar ratio is used. The production amount of the deactivated substance itself may be used as an index.

Furthermore, the activity index of the polymerization reaction can be judged based on the degree of formation of the deactivated substance. For example, by plotting experimental data, it is possible to obtain a relational expression (approximate curve) between the catalyst deactivation material generation amount and the polymerization activity index (see, for example, FIG. 2 described later).

<Determination of start of increase and stop of increase>
The polymerization activity index is determined based on the degree of formation of the deactivated substance. Furthermore, the start of increase and / or stop of increase is determined based on the polymerization activity index. The degree of formation of the deactivated substance itself may be used as a criterion for starting the increase and / or stopping the increase.

For example, when the polymerization activity index falls below the first reference value, the cocatalyst is supplied in an increased amount compared to before the polymerization activity index falls below the first reference value. If the first reference value is set to 80% or more (corresponding to a 4-VCH / DEAC molar ratio of 2.5 or less), sufficient recovery can be expected in practice.

On the other hand, when the polymerization activity index becomes equal to or higher than the second reference value by increasing the amount of cocatalyst supplied, the increase is stopped and the same amount of auxiliary catalyst as before the polymerization activity index becomes lower than the first reference value. Supply catalyst. If the second reference value is set to 95% or higher (corresponding to a 4-VCH / DEAC molar ratio of 2.1 or lower), it can be considered that the second standard value has been sufficiently recovered in practice.

It should be noted that the increase stoppage may not be determined based on the second reference value, but when the decrease in 4-VCH / DEAC is eliminated by monitoring the amount of inactivated substance generated (time differentiation = 0).

<Increase ratio>
When it is determined that an increase is necessary, the cocatalyst is supplied after an increase of 5-30%. More preferably, it is increased by 10-20%.

FIG. 1 is a conceptual diagram of a polybutadiene production system. A basic manufacturing method in the manufacturing system will be described.

A polymerization monomer adjustment solution consisting of a butadiene monomer solution is continuously supplied. Water is added in front of the raw material adjustment tank. Next, the cocatalyst is added at a DEAC / TEA molar ratio of 3 in front of the aging tank. Thereafter, a cobalt-based catalyst is added in a polymerization tank to perform polymerization.

Next, in the reaction stop tank, a mixed solution of an anti-aging agent and a reaction stop agent is added to stop the polymerization. The polymer solution obtained by these is dried with a hot air drier to obtain a polymer product.

On the other hand, the monomer to be polymerized is a part, and the monomer solution that has not been polymerized is supplied again as a raw material.

As described above, during continuous production, a catalyst deactivator (4-vinyl-1-cyclohexene (4-VCH)) was generated in the polymerization tank and was affected by the catalyst deactivator. The yield gradually decreases.

FIG. 2 is a graph showing the relationship between the amount of catalyst deactivation material generated and the polymerization activity index, determined based on experimental data. The horizontal axis represents the molar ratio of 4-VCH / DEAC, and the vertical axis represents the polymerization activity index.

The amount of 4-VCH generated is measured by gas chromatography (GC) as needed from the beginning of polymerization. DEAC is continuously supplied in a certain amount.

The polymerization activity index is defined as the yield when a deactivated substance is generated / yield when no deactivated substance is generated. That is, the polymerization activity index when no deactivated substance is generated is set to 100%.

However, simply increasing the amount of cocatalyst breaks the balance between the catalyst and the cocatalyst, making it impossible to obtain a product with desired physical properties. Moreover, since an organoaluminum compound is comparatively expensive, it is not preferable to increase the amount to a dark cloud from an economical viewpoint. Therefore, in the present invention, the following measures are taken.

FIG. 3 is a diagram showing an operation history based on the approximate curve. Details are shown in Table 1.

Example 1 will be described. Now, in the approximate curve 1, it is assumed that the catalyst deactivation material is generated up to 4-VCH /DEAC=2.46 by continuous production, and the polymerization activity index decreases to 80%.

At this time, the first reference value is set to 80%, it is determined that the polymerization activity index is less than or equal to the first reference value, and the amount of promoter increased by 16% is continuously supplied. As a result, it is assumed that the approximate curve 1 gradually shifts to the approximate curve 2. Assuming that the amount of catalyst deactivation material does not change immediately (no change), and the amount of cocatalyst increases, 4-VCH /DEAC=2.12. Therefore, in the approximate curve 2, the polymerization activity index is recovered to 95%.

¡Set the second reference value as 95%, confirm that the second reference value is exceeded, consider it as a sufficient recovery in yield, and stop the increase. That is, it returns to the predetermined supply amount before the increase. The polymerization activity index and the yield are correlated.

This makes it possible to recover the yield without changing the physical properties of the product. Furthermore, since the increase is stopped at an appropriate timing, it is possible to suppress waste of unnecessary promoters.

Example 2 will be described. If an earlier recovery is desired, the first reference value may be set to 80% or more (for example, 90%). When the catalyst deactivation material is generated and 4-VCH /DEAC=1.23, the polymerization activity index is judged to be below the first reference value (90%), and the amount of promoter increased by 16% is continuously added. To supply.

This gradually shifts from the approximate curve 1 to the approximate curve 2 and becomes 4-VCH /DEAC=1.06, and it is theoretically possible to recover the polymerization activity index to 98%.

At this time, the second reference value may be set to 95%, and the increase may be stopped before the polymerization activity index recovers to 98%, assuming that the yield is sufficiently recovered. Of course, more yield recovery may be expected by setting the second reference value to 98%.

Furthermore, it is possible to use the time when the decrease of 4-VCH / DEAC stops (time differentiation = 0) as the determination criterion for stopping the increase without determining with the second reference value.

Example 3 (reference example) will be described. It is assumed that a catalyst deactivating material is generated, 4-VCH /DEAC=7.33, and the polymerization activity index is lowered to 34%. At this point, when the amount is increased by 16%, the curve gradually shifts from the approximate curve 1 to the approximate curve 2 to 4-VCH /DEAC=6.32, and theoretically, the polymerization activity index can be recovered to 83%.

However, recovery of about 83% may be considered inadequate in practice.

By the way, when the amount of the cocatalyst is not increased, the approximate curve does not shift, the ratio of 4-VCH / DEAC only increases, and the polymerization activity index is decreasing.

According to the above examples, the cocatalyst increase was started before the polymerization activity index decreased to 80%, and it was confirmed that the polymerization activity index had recovered to 95% or more, and the cocatalyst increase was stopped. preferable.

FIG. 4 is a diagram for explaining the results when the present invention is applied to an actual machine. The horizontal axis represents time (year / month) and the vertical axis represents average yield (%). In the actual machine, a plurality of brands are manufactured at random, and the yield is obtained based on the average production amount of the brands.

The average yield (%) was between 99% and 100%, but the average yield (%) gradually decreased from April of the previous year. Therefore, the cocatalyst increase was started in January of this year when the polymerization activity index was 80% (the polymerization activity index and the yield were correlated).

When the cocatalyst increase was continued, the yield recovery trend was observed. When the polymerization activity index recovered to 95% (January of this year), the cocatalyst increase was stopped.

Thereafter, the co-catalyst was supplied by returning to the predetermined supply amount before the increase. The yield was almost 100%.

-Control system-
FIG. 5 is a functional block diagram relating to a control system for increasing / stopping increase.

The control system includes a reference value storage unit 11, a deactivated substance detection unit 12, an increase start / stop determination unit 13, and a promoter supply amount adjustment unit 14.

The reference value storage unit 11 stores the first reference value and the second reference value. The first reference value and the second reference value are set in advance based on experimental data.

The deactivated substance detection unit 12 detects the amount of deactivated substance generated at any time through gas chromatography provided in the raw material adjustment tank.

The increase start / stop determination unit 13 determines the start and stop of the increase in the amount of the cocatalyst based on the detected value of the deactivated substance generation amount. First, the polymerization activity index is estimated based on the detected amount of inactive substance generated. When the polymerization activity index falls below the first reference value, a determination to start increasing is made. On the other hand, if the polymerization activity index recovers to the second reference value or more during continuous increase, an increase stop determination is made.

The promoter supply amount adjusting unit 14 continuously supplies a certain amount of promoter. However, in response to an increase start command from the determination unit 13, a continuously increased amount of promoter is supplied. Further, in response to the increase stop command from the determination unit 13, the amount of promoter before the increase is continuously supplied.

-Supplementary items-
・ Additional matter 1
The inventor of the present application added a cobalt-based catalyst and an organoaluminum-based cocatalyst to a butadiene monomer solution to produce a butadiene polymer in a high yield. However, yields have declined as production continues continuously.

The inventor of the present application studied the cause of the decrease in yield and found that 4-vinyl-1-cyclohexene (4-VCH) was generated. And there was a suspicion that 4-VCH might act as a deactivating substance.

・ Additional matter 2
The inventor of the present application studied a method for recovering the yield. First, a method for removing a deactivating substance was examined, but an effective method could not be found. Next, a method for activating the polymerization by increasing the amount of catalyst was examined, but no significant effect was obtained even when the amount of catalyst was increased. Then, it came to pay attention to a co-catalyst.

On the other hand, there was a suspicion that cocatalyst (especially TEA) might be a distant cause of the generation of deactivated substances. Therefore, it was also considered to reduce the amount of cocatalyst supplied. However, the supply amount of the co-catalyst and the catalyst has been determined through various studies, and an optimal amount with a good balance has been determined.

・ Supplement 3
From experiments, it was presumed that a decrease in yield would be suppressed if the amount of promoter was increased (see FIG. 2). However, simply increasing the amount of cocatalyst broke the balance between the catalyst and the cocatalyst, making it impossible to obtain a product with the desired physical properties (difference in branching). Moreover, since an organoaluminum compound is comparatively expensive, it is not preferable to increase the amount to a dark cloud from an economical viewpoint.

Based on this assumption, I came up with a temporary increase in the amount of promoter. When the cocatalyst was temporarily increased after the deactivated material was generated, it was hypothesized that the increased amount (especially the DEAC increased amount) would not support the action of the catalyst but would suppress the action of the deactivated material. That is, it was assumed that the increased amount does not affect the physical properties of the product because it does not act as the promoter.

As a result of experiment, it was confirmed that the physical properties of the product did not change. On the other hand, the yield could be recovered. The validity of the hypothesis was verified as described above.

Note that the increase in the cocatalyst is temporary, so the economic impact is limited.

DESCRIPTION OF SYMBOLS 11 Reference value memory | storage part 12 Deactivated substance detection part 13 Increase start / stop determination part 14 Promoter catalyst supply amount adjustment part

Claims

In a conjugated diene polymerization reaction using an organoaluminum compound as a promoter,
A method for producing a conjugated diene polymer, characterized in that the supply amount of the cocatalyst is adjusted based on the degree of production of a deactivated substance produced in the reaction system.
In a conjugated diene polymerization reaction using an organoaluminum compound as a promoter,
Determining the polymerization activity index of the reaction based on the degree of production of the deactivated substance produced in the reaction system;
When the polymerization activity index falls below the first reference value, the cocatalyst is supplied in an increased amount compared to before the polymerization activity index falls below the first reference value. Manufacturing method of coalescence.
When the polymerization activity index becomes equal to or higher than the second reference value by supplying the cocatalyst in an increased amount, the same amount of the cocatalyst as before the polymerization activity index becomes lower than the first reference value is supplied. The method for producing a conjugated diene polymer according to claim 2.
The polymerization activity index when the deactivated material is not formed is 100,
The method for producing a conjugated diene polymer according to claim 2, wherein the first reference value is set to 80% or more.
The polymerization activity index when the deactivated material is not formed is 100,
The method for producing a conjugated diene polymer according to claim 3, wherein the second reference value is set to 95% or more.
The organoaluminum compound is
6. The process for producing a conjugated diene polymer according to claim 1, comprising an organoaluminum compound containing halogen and an organoaluminum compound not containing halogen.
A system for controlling a conjugated diene polymerization reaction using an organoaluminum compound as a promoter,
A detection unit for detecting the degree of generation of the deactivated substance generated in the reaction system;
A conjugated diene polymer production system comprising: a promoter supply amount adjusting unit that adjusts the supply amount of the promoter based on the detected value.