KR101808476B1 - Method for producing conjugated diene polymer and a production system - Google Patents

Abstract

In the preparation of the conjugated diene polymer, the yield can be recovered if the yield is gradually reduced. The conjugated diene polymer is produced using a transition metal catalyst and an organoaluminum compound as cocatalysts, but with the conjugated diene polymer being continuously produced, the yield is gradually reduced. Correspondingly, the amount of cocatalyst supplied is controlled based on the degree of formation of the inactivating material produced in the reaction system. More specifically, when the degree of production becomes a predetermined value or less, an increase in the amount of the cocatalyst starts. Moreover, when it is determined that the yield is sufficiently recovered, the increase in the amount of the cocatalyst is stopped. In other words, a predetermined amount of cocatalyst is supplied before the increase.

Description

TECHNICAL FIELD [0001] The present invention relates to a conjugated diene polymer,

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

As a method of producing a conjugated diene polymer, there has been proposed a polymerization method in which a transition metal catalyst as a catalyst and an organoaluminum compound as a cocatalyst are added to a solution containing a conjugated dienic monomer (for example, see Patent Documents 1 and 2).

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

Patent Document 1: JP-A-2013-209470 Patent Document 2: JP-A-2013-227524

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

However, since the conjugated diene polymer is continuously produced in the factory, the yield gradually decreases, which is a problem.

The present invention has been developed in view of the above-described problems, and its object is to provide a manufacturing system as well as a method for producing a conjugated diene polymer capable of recovering yield in a case where the yield is gradually reduced.

The inventors of the present invention have been intensively investigating the causes of decrease in yield and countermeasures thereof, and as a result, the present invention has been reached.

The present invention is a method for producing a conjugated diene polymer in which, in a conjugated diene polymerization reaction using an organoaluminum compound as a cocatalyst, the amount of the cocatalyst to be supplied is controlled based on the degree of formation of an inactivating substance produced in the reaction system.

In the present invention described above, the polymerization activity index of the reaction is determined based on the degree of formation of the inactivating substance produced in the reaction system,

When the polymerization activity index is equal to or less than the first reference value, the amount of the co-catalyst supplied increases with respect to the period before the polymerization activity index becomes the first reference value or less.

In the present invention described above, when the polymerization activity index is equal to or greater than the second reference value by supplying an increase amount of the co-catalyst, the co-catalyst is supplied in an amount equal to the amount before the polymerization activity index becomes equal to or less than the first reference value.

In the above-mentioned invention, the polymerization activity index when no inactivating substance is generated is set to 100, the first reference value is set to 80% or more, and the second reference value is set to 95% or more.

In the above-mentioned invention, the organoaluminum compound includes an organoaluminum compound containing a halogen and an organoaluminum compound containing no halogen.

The present invention relates to a system for producing a conjugated diene polymer by controlling a conjugated diene polymerization reaction using an organoaluminum compound as a cocatalyst, the system comprising: a detection unit for detecting the degree of formation of an inactivating substance produced in the reaction system; And a coarse feed amount adjusting unit for adjusting the feed amount of coarse catalyst based on the detected value.

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

1 is a conceptual diagram of a system for producing a conjugated diene polymer.
2 is a graph showing the relationship between the amount of the catalyst deactivation material produced and the polymerization activity index calculated based on experimental data.
3 is a diagram showing an expected operation history.
4 is a bar graph illustrating the results when the present invention is applied to an actual apparatus.
Figure 5 is a functional block diagram belonging to an adjustment system.

<Summary>

The present invention uses a transition metal catalyst and an organoaluminum compound as cocatalysts to prepare a conjugated diene polymer. At the time of preparation, the amount of cocatalyst supplied is controlled based on the degree of formation of the inactivating material produced in the reaction system. More specifically, the amount of cocatalyst starts and increases at an appropriate point in time, and the increase in cocatalyst supply stops at an appropriate point in time. Details thereof are described below.

&Lt; Diene monomer &gt;

Examples of the diene-based monomer in the present embodiment include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, and 2-phenyl-1,3-butadiene. They may be used independently in a single form, or in a mixture of two or more forms. Or they may be used by being polymerized 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 wt%, more preferably in the range of 20 to 70 wt%, and still more preferably in the range of 25 to 50 wt%.

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

&Lt; Transition metal catalyst &

Examples of the transition metal catalyst include cobalt-based catalysts, nickel-based catalysts, neodymium-based catalysts, vanadium-based catalysts, and titanium-based catalysts. Among these, a cobalt-based catalyst or a nickel-based catalyst is preferable, and a cobalt-based catalyst is more preferable. The single type transition metal catalyst may be used alone, or two or more types may be used in combination.

Examples of cobalt-based catalysts include cobalt chloride, cobalt bromide or other cobalt halide salts; Cobalt sulfate, cobalt nitrate or other inorganic acid cobalt salts; Cobalt octoate, cobalt octylate, cobalt naphthenate, cobalt acetate, cobalt malonate, or other organic acid cobalt salts; And cobalt bisacetylacetonate, cobalt trisacetylacetonate, cobalt ethyl acetoacetate, pyridine complexes of cobalt salts, picoline complexes of cobalt salts, ethyl alcohol complexes of cobalt salts, and other cobalt complexes. Of these, cobalt octoate is preferred.

Usually, the addition amount of the cobalt-based catalyst is preferably 1 × 10 ^-7 to 1 × 10 ^-4 mol, and even more preferably 1 × 10 ^-6 to 1 × 10 ^-5 mol, per 1 mol of the diene monomer.

&Lt; Organoaluminum catalyst &

Organoaluminum catalysts are used with transition metal catalysts. The amount of the organoaluminum promoter to be added is preferably in the range of 50 to 2,000 moles per mole of the transition metal catalyst.

In particular, in this embodiment, an organoaluminum compound containing a halogen and an organoaluminum compound containing no halogen are used in combination.

As the non-halogenated organoaluminum compound, trialkylaluminum, dialkylaluminum hydride, alkylaluminum sesquihydride and other halogenated organoaluminum can be used. Among them, trialkylaluminum is preferable, and triethylaluminum (TEA) is more preferable.

Examples of halogenated organoaluminum are dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum dichloride, alkylaluminum dibromide, alkylaluminum sesquichloride, and alkylaluminum sesquibromide. Among them, an organic aluminum chloride is preferable, and diethyl aluminum chloride (DEAC) is more preferable.

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

&Lt; Degree of inactivating substance and produced inactivating substance &gt;

4-vinyl-1-cyclohexene (4-VCH) is produced as an inactivating substance (toxic substance) when a cobalt catalyst and an organoaluminum cocatalyst are added to a butadiene monomer solution and polymerized. The amount of the inactivating material produced is measured by gas chromatography (GC) at any time after the initiation of polymerization.

As a measure of the degree of deactivation material produced, the molar ratio of the amount of halogenated organoaluminum fed to the amount of deactivation material produced is used. For example, the molar ratio of 4-VCH / DEAC is used. The amount of deactivation material produced by itself can also be used as an indicator.

Moreover, the activity index of the polymerization reaction can be determined based on the amount of the inactivating material produced. For example, by plotting experimental data, it is possible to obtain a relational expression (approximate curve) between the amount of the catalyst deactivating substance to be produced and the polymerization activity index (see, for example, FIG. 2 described later).

&Lt; Determination of the start of the positive increase and determination of the stop of the positive increase &

The polymerization activity index is determined based on the degree of production of the inactivating substance. Moreover, the start of the increase of the amount and / or the stop of the increase of the amount are determined based on the polymerization activity index. The amount of deactivation material produced by itself can be used as a criterion for determining the onset of positive increase and / or the halting of positive increase.

For example, when the polymerization activity index is equal to or less than the first reference value, the amount of the cocatalyst to be supplied increases before the polymerization activity index becomes equal to or less than the first reference value. When the first reference value is set to 80% or more (equal to the 4-VCH / DEAC molar ratio of about 2.5 or less), a sufficient recovery can actually be expected.

On the other hand, when the polymerization activity index becomes equal to or greater than the second reference value through the increased supply amount of the cocatalyst, the amount increase is stopped, and the amount of the catalyst having the same amount as that before the polymerization activity index becomes the level below the first reference value level . If the second reference value is at a level of 95% or more (equivalent to a molar ratio of 4-VCH / DEAC of about 2.1 or less), it can be considered that the recovery is actually sufficiently obtained.

(Latency = 0) observed to stop the reduction based on monitoring the amount of deactivation material produced by the 4-VCH / DEAC, rather than determining the stopping of the positive increase based on the second reference value Can be used as a criterion for determining the stop of the increase.

<Increase rate>

If it is deemed necessary to increase the amount, the amount of cocatalyst is increased by 5 to 30%, preferably by 10 to 20%.

Example

1 is a conceptual diagram of a system for producing polybutadiene. The basic manufacturing method for the manufacturing system is described below.

The polymerized monomer conditioning solution made from the butadiene monomer solution is continuously supplied. Water is added prior to the raw material conditioning tank, and then the cocatalyst is added to the AC / TEA molar ratio 3 prior to the aging tank. Next, the cobalt-based catalyst is added to the polymerization tank and polymerization is carried out.

Next, the mixed solution of the anti-aging agent and the reaction terminator is added to the polymerization termination tank to terminate the polymerization. The polymer solution thus obtained is dried using a hot-air dryer to obtain a polymer product.

On the other hand, the monomer to be polymerized is a part, and the un polymerized monomer solution is once again supplied as a raw material.

While continuously performing the production in this manner, a catalyst deactivation material (4-vinyl-1-cyclohexene (4-VCH)) is produced in the polymerization tank, wherein the process is effected by the catalyst deactivation material, .

2 is a graph showing the relationship between the amount of the catalyst deactivation material produced and the polymerization activity index calculated 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 produced is measured at any time after the start of polymerization using gas chromatography (GC). DEAC is supplied continuously in a certain amount.

The polymerization activity index is defined as (yield when the inactivating material is produced) / (yield when no inactivating material is produced). In other words, the polymerization activity index when no inactivating material is produced is treated as 100%.

However, when the amount of the cocatalyst is simply increased, the balance between the catalyst and the cocatalyst is destroyed, and a product having desired physical properties may not be obtained. Moreover, organoaluminum compounds are relatively expensive, and therefore from an economic point of view, irregular increase of organoaluminum compounds is undesirable. The following types of measures are therefore taken in the present invention.

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

[Table 1]

Embodiment 1 is described below. From the approximate curve 1 it is assumed that the catalyst deactivation material is produced through continuous production up to 4-VCH / DEAC = 2.46 and the polymerization catalyst activity index drops to 80%.

At this time, the first reference value is set to 80%, the polymerization activity index falls below the first reference value, and the amount of the cocatalyst increased by 16% is determined to be continuously supplied. Through this, it is expected to progress gradually from the approximate curve 1 to the approximate curve 2. Assuming that the amount of catalyst deactivation material produced does not change immediately (unchanged), we get 4-VCH / DEAC = 2.12 because the amount of cocatalyst is increased. Therefore, the polymerization activity index is restored to 95% for the approximate curve 2.

When it is confirmed that the second reference value is set to 95% and that the polymerization activity index has reached the second reference value or more, a sufficient yield recovery is assumed, and the positive increase is stopped. In other words, the amount of cocatalyst supplied is returned to the prescribed amount before the supply amount is increased. Note that there is a correlation between the polymerization activity index and the yield.

Through this, the yield can be recovered without changing the physical properties of the product. Moreover, since the supply amount increase is stopped at an appropriate time, unnecessary residue of the cocatalyst can be suppressed.

The second embodiment will be described next. If faster recovery is desired, the first reference value can be set to 80% or more (e.g., 90%). When the catalyst deactivation material is produced and 4-VCH / DEAC = 1.23 is reached, the polymerization activity index is below the first reference value (90%) and the amount of cocatalyst increased to 16% is found to be continuously supplied.

Through this, it gradually progresses from the approximate curve 1 to the approximate curve 2, reaching 4-VCH / DEAC = 1.06, theoretically the polymerization activity index can recover to 98%.

At this time, the second reference value is set to 95%, and sufficient yield recovery state is estimated, and the positive increase can be stopped before the polymerization activity index is recovered to 98%. Of course, a larger yield recovery can be expected by setting a second reference value of 98%.

Furthermore, rather than determining the stop of the increase in the amount based on the second reference value, the instant when the 4-VCH / DEAC stops decreasing (parallax = 0) can also be used as a criterion for determining the stop of the increase.

Embodiment 3 (reference embodiment) will be described next. Assume that a catalyst deactivation material is produced, 4-VCH / DEAC = 7.33 is reached, and the polymerization activity index has dropped to 34%. If the amount is increased by 16% at this point, a gradual transition from the approximate curve 1 to the approximate curve 2 occurs, reaching 4-VCH / DEAC = 6.32 and theoretically the polymerization activity index can recover to 83%.

However, in practice, a recovery rate of about 83% is likely to be considered inappropriate.

Thus, if the amount of cocatalyst is not increased, the approximation curve does not move, only the ratio of 4-VCH / DEAC increases and the polymerization activity index decreases.

According to the above-described embodiment, preferably, the increase in the amount of the cocatalyst is initiated before the polymerization activity index is reduced to 80%, wherein the increase in the amount of the cocatalyst is such that the polymerization activity index is restored to 95% Stop when confirmed.

4 is a bar graph illustrating the results when the present invention is applied to an actual apparatus. The horizontal axis represents time (year / month), and the vertical axis represents yield (%). Note that a plurality of brands are irregularly generated in actual devices, and the yield is determined based on the average generation degree of the brand.

The average yields ranged from 99% to 100%, but the average yield (%) decreased from the beginning of April of the previous year. Thus, in January of this year when the polymerization activity index became 80% (there is a correlation between the polymerization activity index and the yield), the amount of cocatalyst started to increase.

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

Next, the feed amount was returned to the prescribed feed amount before the increase, where the cocatalyst was supplied in the above amount. Next, the degree of production was changed to a yield of almost 100%.

~ Control system ~

5 is a functional block diagram pertaining to an adjustment system that initiates a positive increase and halts a positive increase.

The control system includes a reference value storage unit 11, an inactive material detection unit 12, a positive increase / decrease determination unit 13, and a catalyst supply amount adjustment unit 14.

The reference value storage unit 11 stores a first reference value and a second reference value, and the first reference value and the second reference value are preset based on the experimental data.

The deactivating material detecting unit 12 detects the amount of deactivating material generated by using the gas chromatography apparatus provided in the raw material adjusting tank at any time.

The amount increase start / stop determination unit 13 determines when to start increasing the amount of the co-catalyst and when stopping the increase based on the detected value of the amount of the inactivating material to be produced. First, the polymerization activity index is evaluated based on the detection value for the amount of the inactivating material to be produced. When the polymerization activity index falls below the first reference value, the conditioning system decides to initiate an increase in the amount of cocatalyst. On the other hand, when the polymerization activity index recovers to the second reference value or more when the increase in the amount continues, the control system decides to stop the increase.

The coarse feed rate control unit 14 continuously feeds a uniform amount of coarse feed. However, when an instruction to start increasing its amount is received from the decision unit 13, an increasing amount of cocatalyst is continuously supplied. Moreover, when an instruction to stop the increase of its amount is received from the decision unit 13, the same amount of cocatalyst is continuously supplied before the increase.

~ Supplementary information ~

· Supplement 1

The inventors of the present invention prepared a butadiene polymer in high yield by adding a cobalt-based catalyst and an organoaluminum-based cocatalyst to a butadiene monomer solution. However, yields decreased as production continued.

When the inventors of the present invention studied the cause of the decrease in yield, they found that 4-vinyl-1-cyclohexane (4-VCH) was produced. Moreover, the inventors of the present invention have suspected that 4-VCH can act as an inactivating substance.

· Supplement 2

The inventors of the present invention investigated methods for recovering yield. First, a method of removing the inactivating material was investigated, but no effective method was found. Next, a method of increasing the amount of the catalyst to activate the polymerization was investigated, but even when the amount of the catalyst was increased, a remarkable effect was not obtained. Therefore, the present inventors focused their attention on cocatalyst.

On the other hand, the inventors of the present invention have suspected that cocatalyst (especially TEA) was the main cause of the production of deactivated material. Therefore, the reduction of the amount of cocatalyst supplied was investigated. However, the optimal balance of cocatalyst and catalyst feed was determined through various experiments, and therefore the investigation of changes including increasing and decreasing these amounts was not a mere matter.

· Supplement 3

Through experiments it was assumed that as the amount of cocatalyst is increased, the decrease in yield can be suppressed (see FIG. 2). However, when the amount of the cocatalyst was simply increased, the balance between the catalyst and the cocatalyst was destroyed, and a product having desired physical properties was not obtained (the branching degree was different). Furthermore, since the organoaluminum compound is relatively expensive, an irregular increase in the amount of the organoaluminum compound is not preferable from an economic point of view.

Based on this type of preface, we have arrived at the idea that the amount of cocatalyst is temporarily increased. The present inventors have hypothesized that an increase (particularly an increase in DEAC) when the amount of cocatalyst is temporarily increased after the formation of the inactivating substance can suppress the action of the inactivating substance rather than assisting the action of the catalyst. In other words, the present inventors have assumed that the amount of increase does not affect the physical specification of the product since the original function of the cocatalyst is not performed.

Experimental results confirm that the physical properties of the product do not change. On the other hand, the yield was recoverable, and the hypothesis was validated as described above.

Note that the economic impact is limited because the increase in the amount of cocatalyst is transient.

11: reference value storage unit
12: deactivation material detecting unit
13: Quantity increase start / stop determination unit
14: Catalyst feed rate control unit

Claims (7)

In a conjugated diene polymerization reaction using a transition metal catalyst as a catalyst and an organoaluminum compound as a cocatalyst,
Determining the polymerization activity index of the reaction based on the degree of formation of the inactivating substance generated in the reaction system,
The polymerization activity index when the inactivating substance is not produced is 100, the first reference value is set to a range of 34% or more,
Wherein when the polymerization activity index is equal to or less than the first reference value, the promoter is increased and supplied before the polymerization activity index becomes equal to or less than the first reference value.
&Lt; / RTI &gt; The method according to claim 1,
The polymerization activity index when the inactivating substance is not produced is set to 100, the second reference value is set to a range of 83% or more,
Wherein the co-catalyst is fed in an increased amount so that when the polymerization activity index becomes equal to or higher than the second reference value, the co-catalyst is supplied in the same amount as before the polymerization catalyst activity index becomes equal to or less than the first reference value. Way. The method for producing a conjugated diene polymer according to claim 1, wherein the polymerization activity index when no inactivating substance is generated is 100, and the first reference value is set to 80% or more. The method for producing a conjugated diene polymer according to claim 2, wherein the polymerization activity index when no inactivating substance is generated is set to 100, and the second reference value is set to 95% or more. The method for producing a conjugated diene polymer according to any one of claims 1 to 4, wherein the organoaluminum compound comprises an organoaluminum compound containing a halogen and an organoaluminum compound containing no halogen. A system for controlling a conjugated diene polymerization reaction using a transition metal catalyst as catalyst and an organoaluminum compound as cocatalyst,
A detection unit for detecting the degree of formation of an inactivating substance generated in the reaction system; And
The polymerization activity index when the inactivating substance is not produced is 100 and the production criterion value of the inactivating substance is set within the range of the degree of formation of the inactivating substance corresponding to the polymerization activity index of 34%
The amount of the inactivating substance detected by the detecting unit is equal to or greater than the reference level of deactivation of the inactivating substance, the amount of the inactivating substance is increased compared with before the deactivation substance is not more than the reference level of deactivation, A system for producing a conjugated diene polymer, comprising a catalyst feed rate control unit. delete

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