JPS6048526B2 - Butene polymer purification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves the removal of the catalyst contained in the polymer when a liquid or semi-solid butene polymer (generally referred to as polybutene) is obtained by polymerizing butenes using a Friedel-Crafts type catalyst. The present invention relates to a method for purifying butene polymers.

If the catalyst is contained in the polymer, the butene polymer product will be easily colored and deteriorated, failing quality and performance tests, and its uses will be limited.In particular, once colored, it will be difficult to decolor, so the polymerization reaction will be delayed. It is necessary to remove the catalyst at the stage after completion of the process, and this situation has been studied in various fields and various reports have been made.

For example, conventional removal methods include physical removal methods such as sedimentation, adsorption, and filtration methods, aqueous solutions such as hydrochloric acid and sulfuric acid, organic chemicals such as alcohols, get compounds, and ethers, There are chemical removal methods using ammonia gas, ammonia water, alkaline aqueous solutions such as sodium hydroxide, calcium hydroxide, etc., but all of these methods have the following drawbacks, and further improvements are desired.

In other words, in (1), when using the sedimentation separation method, the catalyst residue that has settled in the sedimentation tank is extracted continuously or at regular intervals, but when it is extracted, a certain amount of polymer and unreacted substances are discharged from the system. In addition, the removed catalyst residue must be carefully disposed of, making the operation cumbersome.Furthermore, this method cannot hope to completely remove the catalyst by itself.
Implementation in combination with other physical or chemical methods is unavoidable.

(2) In other physical methods such as adsorption and filtration methods,
The white clay used is covered with catalyst residue, catalyst con J flex, oil, etc., which not only requires a lot of effort and expense for subsequent treatment, but also reduces its performance. Furthermore, when these adsorption methods and filtration methods are used, unreacted butenes in the polymerization solution are polymerized by the remaining catalyst, resulting in exothermic temperature rise, which inevitably has an adverse effect on the product. (3) In addition, in chemical methods in which the polymerization solution is washed with water or pickled, corrosion and damage to equipment and equipment due to the generation of hydrogen chloride cannot be avoided when aluminum chloride catalysts are used. (4) When organic chemicals are used, the chemicals not only remain in the polymerization solution and adversely affect the quality of the product, but also the recovered unreacted materials obtained by separating the polymer are returned to the polymerization process. In some cases, it becomes a catalyst poison and inhibits the polymerization reaction. (5) In the method of blowing ammonia gas into the polymerization solution, the remaining catalyst is deactivated, so the temperature increase as described above can be avoided, but ammonia and aluminum chloride catalyst form a complex, and this product Removal of the clay requires a combination of sedimentation, adsorption, or filtration, so the above-mentioned drawbacks associated with physical methods are unavoidable, and the complex layer formed on the surface of the clay has a high pressure drop. increases, making continuous operation difficult. (6) There are various methods that use basic aqueous solutions, but none of them are satisfactory. For example, in the method that uses ammonia water, a part of it accompanies the unreacted flow that is recycled. In the method using an aqueous calcium hydroxide solution, the neutralization and removal effect of the catalyst is poor and favorable results cannot be obtained. (7) In the conventional method using a caustic alkaline aqueous solution, the aqueous solution is applied to the polymerization solution to precipitate and remove the resulting aluminum hydroxide. This is done through complicated processing, such as separating a portion by sedimentation, then washing with alkaline to separate it as aluminum hydroxide, and then removing the aluminum hydroxide particles, which are difficult to sediment, by passing through a layer of clay. It is in. However, although the method of the present invention is carried out using the same caustic alkali, it is much easier to carry out than the conventional method and has superior effects, and in particular does not require methods such as sedimentation separation and/or adsorption separation. This is a surprising result, and its gist is that a polymerization solution containing a catalyst obtained by polymerizing butenes using a Friedel-Crafts type catalyst is brought into contact with an aqueous caustic solution to remove the catalyst. Neutralization, deactivation, and dissolving the resulting neutralized product in the above aqueous solution. Then, in the method of separating the aqueous solution and washing the obtained polymerization liquid with water, the alkaline concentration of the caustic alkali aqueous solution subjected to the above-mentioned contact is maintained at PHIO or more after the above-mentioned neutralization, deactivation, and dissolution. The method for purifying a butene polymer is characterized in that the aqueous solution is brought to the necessary concentration and the volume-to-volume ratio of the aqueous solution to the polymerization solution is 112 or more, and the details thereof will be described below. In the present invention, butenes refer to isobutene, butene-1, and butene-2, which are carbon atoms obtained during ethylene production.

It is contained as butenes together with butanes in the fraction (also known as B-B fraction). Industrially, such a fraction is used as a raw material, and the butanes and unreacted butenes in the distillate act as a polymerization solvent, so it is difficult to perform a polymerization reaction using this fraction as a raw material. It is convenient because it can be done without adding solvents or diluents. A Friedel-Crafts type catalyst is aluminum chloride (AICI).

), metal halides such as iron chloride (FeCl3), or boron fluoride, but industrially AlCl3
is used, so this chloride will be described below as an example. Also, aluminum chloride has a ratio of 0.01 to 1 for butenes.
It is used in a proportion of 0.05 to 0.5% by weight.
Preferably used in The polymerization is carried out at a temperature of -70 to +1000°C, preferably from -10 to +50°C, and under pressure necessary to maintain the polymerization system in the liquid phase. The butene polymer obtained by polymerization in the fraction has a molecular weight of 200 to 30.
00) It is liquid or semi-solid at room temperature, and is taken out from the polymerization reactor as a polymerization liquid along with butanes and unreacted butenes in the distillate and subjected to catalyst removal treatment, but the butenes are removed during polymerization. If the polymerization conversion rate is increased too much, the viscosity of the polymerization solution will increase, making it difficult to remove the catalyst.
It is preferable to subject the catalyst removal treatment to about 0 to 80%. Immediately after the polymerization solution thus obtained is taken out of the polymerization reactor, it is transferred to a container equipped with a stirrer and treated with an aqueous solution of caustic alkali in the following manner. In the present invention, caustic alkali (NaOH or KOH) is hereinafter simply referred to as alkali, and aqueous caustic alkaline solution is also referred to as aqueous alkaline solution or simply aqueous solution.

The alkaline concentration and required amount of the alkaline aqueous solution to be brought into contact with the polymerization solution are determined by the amount of alkali required for neutralizing and deactivating the catalyst,
All you need to know is the pH value to be maintained when the neutralized product is dissolved, and the amount of alkali required for neutralization and deactivation is a theoretical value.Also, if you know the solubility of aluminum hydroxide at the above pH value, neutralization is possible. , the required minimum volume of alkaline aqueous solution necessary to dissolve all of the aluminum hydroxide generated by deactivation and the alkali amount required to maintain the minimum volume of alkaline aqueous solution at the above pH value can be easily calculated. be done.

However, what is important for art is that the object of the present invention cannot be achieved with the amount of calculation obtained in this way. This is because the amount of alkaline aqueous solution obtained by such calculation does not necessarily meet the requirements for separation from the polymerization liquid. Now let's talk about the influence of the pH value on the solubility of aluminum hydroxide and the separability of the aqueous solution and polymerization solution.
.

AICI of 0.4Qw% for the fraction. If a catalyst is used, the resulting neutralization product A1 (0H). The amount of alkaline aqueous solution is 0.24W% based on the polymerization solution, and the amount of alkaline aqueous solution necessary to dissolve this neutralized product at room temperature is A1 (0H) based on the aqueous solution. If the pH is 9, the volume of the polymerization solution is about 5.5 times that of the polymerization solution, which leads to the consumption of a huge amount of water, the increase in the size of the equipment, the waste of electric power for stirring, and the waste of chemicals. On the other hand, when the pH difference increased by only 1, the solubility of the neutralized product increased tenfold, reducing the amount of water used to 1110, or about 5.5 of the amount of polymerization solution.
However, if an attempt is made to further increase the pH value to increase solubility and thereby reduce the amount of water used, the alkaline aqueous solution forms an emulsion with the polymerization solution and cannot be separated.
An example of this case is shown using an alkaline aqueous solution of PHL3 for the same polymerization solution as above, and the required amount of the aqueous solution is Al
From the solubility of (0H)3, it was found that only 1127 volume of the polymerization solution was sufficient, which at first glance seems to be sufficient.
Both liquids form an emulsion upon stirring and cannot be separated, making it impossible to achieve the purpose of purification. The inventors of the present invention have conducted research to solve this problem, and have found that if an aqueous alkaline solution is used at least 112 times the volume of the polymerization solution, regardless of its pH value, the volume of the alkali aqueous solution relative to the polymerization solution is ratio to 112
When used in the above manner, it was discovered that both liquids were easily separated by standing, and it was also confirmed that when used at this volume ratio, the neutralized product in the polymerization liquid migrated well into the aqueous solution. This is what was done.

In the case of using the alkaline aqueous solution of PHLO, Al(0H
).

The amount of aqueous solution required for dissolving is 5.5 times the volume of the polymerization solution, and when using an alkaline aqueous solution of PHL3, the volume is 112 times the volume of the polymerization solution.
(0H). The minimum amount of alkali aqueous solution required for dissolution is in the former case, which can be separated by stirring and standing still, but in the latter case, it cannot be separated because the volume of the former (5.5 times) is the volume of the polymerization liquid. It is understood that the volume is 112 times or more. An effective and appropriate reduction in the amount of water used can be achieved by appropriately adjusting the alkaline concentration of the alkaline aqueous solution used for contacting, but too concentrated alkaline aqueous solution will not only corrode the equipment but also cause damage to the alkaline polymerization solution. remains in
This becomes a burden on the washing process and unnecessarily increases the expense.

Therefore, the alkaline concentration of the alkaline aqueous solution used for contact is 1
It is preferably 0 w% or less, and the catalyst (AlCl3
), and after dissolving the neutralized product, PHII ~ 12
It is preferable to adjust the volume ratio of the alkaline aqueous solution to the polymerization liquid in the range of 112 to 2 in advance. Example 1 800cc of C4 fraction containing 36w% of isobutylene was
The mixture was cooled to °C and placed in a glass 11 autoclave equipped with a stirrer, a thermometer and a jacket, and then 0.50 da of aluminum chloride dispersed in polybutene having a molecular weight of about 300 was press-fitted into the autoclave. 13°C
So 1. After carrying out the polymerization reaction for a period of time, the obtained polymerization liquid 700
cc = 700cc of aqueous solution containing 0.731 da of caustic soda
The mixture was transferred to a glass 21 autoclave equipped with a stirrer and stirred for 5 minutes.

After stirring, the mixture was allowed to stand for about 5 minutes, and the aqueous solution became a lower layer, and the polymerization liquid became a transparent upper layer, completely separated from the aqueous solution. The pH of the aqueous solution separated into the lower layer was 12. Next, separate the lower layer aqueous solution and put 700cc into an autoclave.
of water was injected under pressure, stirred for 5 minutes, allowed to stand for 5 minutes, and then separated.

The polymerization solution obtained by washing with water was heated at 120°C for 1 hour while maintaining a reduced pressure of 10rr LIm of mercury to remove unreacted C, fractions and light polybutene, and the average molecular weight was 900.
160 g of purified liquid polybutene was obtained. The quality of this polybutene is determined by hue test, A1 content, C1 content, N
It passed each analytical test for the a content, and the results were as shown in Table 1. In this example, the volume ratio of the alkaline aqueous solution is 1:1,
An example will be shown in which the pH of the separated aqueous solution is 12, the former is 11 or more, and the latter is 10 or more.

The volume ratio of the alkaline solution is the volume ratio of the amount of the caustic soda aqueous solution to the amount of the polymerization solution, and the pH of the separated aqueous solution is the volume ratio of the amount of the aqueous solution of caustic soda to the amount of the polymerized solution. It refers to the aqueous solution obtained, and the same applies to each example below.

Example 2 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 21 autoclave equipped with a stirring device and containing 700 cc of an aqueous solution containing 0.479 da of caustic soda.
When stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated in the same manner as in Example 1, and the PH of the aqueous solution obtained in the lower layer was
It was 11.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900.

Moreover, the quality of this polybutene was as shown in the first table, and one of the products passed the test. In this example, the volume ratio of the alkaline aqueous solution is 1:1, the pH of the separated aqueous solution is 11, and the former is 112.
An example in which the latter is 10 or more is shown above.

Comparative Example 1 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 21 autoclave equipped with a stirring device containing 700 cc of an aqueous solution containing 0.452 d of caustic soda, and stirred in the same manner as in Example 1. When left to stand still, the polymerization liquid was separated in the same manner as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 9.
It was hot.

Thereafter, the same procedure as in Example 1 was carried out to obtain 160 Da of liquid polybutene having an average molecular weight of 900.

Moreover, this polybutene had the quality listed in the first table and was a rejected product. Note that this example shows that even if the volume ratio of the alkaline aqueous solution is greater than 112, if the pH of the separated aqueous solution is less than 10, a passing product cannot be obtained.

Example 3 Polymerization solution 700.0% obtained by polymerization in the same manner as in Example 1. cc
was transferred to a glass 21 autoclave equipped with a stirrer and containing 350 cc of an aqueous solution containing 0.591 Da of caustic soda, stirred in the same manner as in Example 1, and allowed to stand still. As in Example 1, the polymerization liquid formed in the upper layer. The pH of the aqueous solution obtained as the lower layer after separation was 12.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900. The quality of this polybutene was as shown in the first table, and it was a passed product. In this example, the volume ratio of the alkaline aqueous solution is 112, the pH of the separated aqueous solution is 12, the former is 112 or more, and the latter is 1.
An example of the case of 0 or more is shown.

Example 4 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was added to 350 cc of an aqueous solution containing 0.465 d of caustic soda in a glass 21mm tube equipped with a stirrer. Transfer to autoclave
When stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was
It was 11.

Thereafter, the same procedure as in Example 1 was carried out to obtain 160 g of liquid polybutene having an average molecular weight of 900.

Moreover, this polybutene had the quality shown in the first table and was a passed product. In this example, the volume ratio of the alkaline aqueous solution is 112.
, the pH of the separated aqueous solution is 11, and the former is 11
An example where the number is 2 or more and the latter is 10 or more will be shown.

Comparative Example 2 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass autoclave equipped with a stirrer and containing 350 cc of an aqueous solution containing 0.452 y of caustic soda. When the mixture was stirred and left to stand, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 9.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900.

Moreover, this polybutene was a rejected product that had the quality listed in the first table. In this example, the volume ratio of the alkaline aqueous solution is 11.
This is an example showing that even if the pH value of the separated aqueous solution is 2, if the pH of the separated aqueous solution is less than 10, a passing product cannot be obtained.

Example 5 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 31 autoclave equipped with a stirring device and containing 1400 cc of an aqueous solution containing 1.011 y of caustic soda.
When the mixture was stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 12.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900. The quality of this polybutene was as shown in the first table, and it was an acceptable product. In this example, the volume ratio of the alkaline aqueous solution is 2, and the PH of the separated aqueous solution is
is 12, the former is 112 or more, and the latter is 10 or more.

Example 6 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 31 autoclave equipped with a stirring device and containing 1400 cc of an aqueous solution containing 0.457 y of caustic soda.
When stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 10.

Thereafter, the same procedure as in Example 1 was carried out to obtain 160 da of liquid polybutene with an average molecular weight of 900. The quality of this polybutene was as shown in the first table, and it was a passed product. In this example, the volume ratio of the alkaline aqueous solution is 2, and the pH of the separated aqueous solution is 1.
0, the former is equal to or greater than IP, and the latter is equal to or greater than 10.

Comparative Example 3 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 31 autoclave equipped with a stirring device and containing 1400 cc of an aqueous solution containing 0.452 y of caustic soda.
When the mixture was stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 9.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900.

Moreover, this polybutene was a rejected product having the quality listed in the first table. This example shows that even if the volume ratio of the alkaline aqueous solution is 1 to 2 or more, if the pH of the separated aqueous solution is less than 10, a passing product cannot be obtained.

Comparative Example 4 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 21 autoclave equipped with a stirring device containing 230 cc of an aqueous solution containing 0.452 y of caustic sorter, and stirred in the same manner as in Example 1. When left to stand still, the polymerization solution was Example 1.
The upper layer was separated in the same manner as above, and the pH of the aqueous solution obtained in the lower layer was 10.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900.

Moreover, this polybutene was a rejected product having the quality listed in the first table. In addition, in this example, the volume ratio of the alkaline aqueous solution is 1
This is an example showing that if it is smaller than '2, a passing product cannot be obtained even if the pH of the separated aqueous solution is 10.

Comparative Example 5 700 Cc of polymerization solution obtained by polymerization in the same manner as in Example 1
was transferred to a glass 2e autoclave equipped with a stirrer and containing 230 cc of an aqueous solution containing 0.543 y of caustic sorter.
When the mixture was stirred and left to stand in the same manner as in Example 1, the polymerization liquid was separated into an upper layer as in Example 1, and the pH of the aqueous solution obtained in the lower layer was 12.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900.

Moreover, this polybutene was a rejected product having the quality listed in the first table. In this example, the volume ratio of the alkaline aqueous solution is 11.
This is an example showing that if it is less than 2, a passing product cannot be obtained even if the pH of the separated aqueous solution is 10 or more.

Comparative Example 6 700 cc of the polymerization solution obtained by polymerization in the same manner as in Example 1 was transferred to a glass 21 autoclave equipped with a stirring device containing 700 cc of 3.56 w% ammonia water, stirred in the same manner as in Example 1, and allowed to stand still. When the polymerization solution was placed in the same manner as in Example 1, it was separated into an upper layer, and the pH of the aqueous solution obtained in the lower layer was 12.

Thereafter, the same procedure as in Example 1 was carried out to obtain 160 da of liquid polybutene having an average molecular weight of 900.

Moreover, this polybutene was a rejected product having the quality listed in the first table. In addition, in this example, when using an aqueous solution of a base other than caustic alkali, the volume ratio of the aqueous solution is 11 times higher than that of the previous example, and even if the pH of the separated aqueous solution is 10 or more, a passing product cannot be obtained. This is an example.

In the case of this example, the recovered unreacted C.

Ammonia gas was present in the fraction at 95 ppm. Comparative Example 7 700 cc of a polymerization solution obtained by polymerization in the same manner as in Example 1 was added to 700 cc of an aqueous solution containing 5.67 y of calcium hydroxide.
The polymerization solution was transferred to a glass 21 autoclave equipped with a stirrer, stirred in the same manner as in Example 1, and allowed to stand still. As in Example 1, the polymerization liquid was separated into an upper layer, and the pH of the aqueous solution obtained in the lower layer was It was 12.

Thereafter, the same procedure as in Example 1 was carried out to obtain liquid polybutene 160y having an average molecular weight of 900. Moreover, this polybutene is
The product was rejected and had the quality listed on the label. Note that the volume ratio of the calcium hydroxide aqueous solution and the pH of the separated aqueous solution in this example are an example showing that they are the same as in Comparative Example 6.

Claims (1)

[Claims] 1. A polymerization solution containing a catalyst obtained by polymerizing butenes using a Friedel-Crafts type catalyst is brought into contact with an aqueous caustic alkali solution to neutralize and deactivate the catalyst, resulting in a neutralized product. In the method of dissolving a substance in the aqueous solution and then separating the aqueous solution and washing the obtained polymerization liquid with water, the alkali concentration of the aqueous caustic alkali solution to be subjected to the contact is adjusted to the level of neutralization and deactivation described above. . A method for purifying a butene polymer, which comprises adjusting the aqueous solution to a concentration necessary to maintain a pH of 10 or higher after dissolution, and adjusting the volume ratio of the aqueous solution to the polymerization solution to 1/2 or higher. 2. The method for purifying a butene polymer according to claim 1, wherein the Friedel-Crafts type catalyst is aluminum chloride. 3. The method for purifying a butene polymer according to claim 1, wherein the caustic alkali is sodium hydroxide.