KR100851639B1 - Method for preparing high-reactive polyisobutene using high concentrated isobutene - Google Patents

Abstract

A method for preparing highly reactive polyisobutene containing 70 wt% or more of vinylidene is provided to improve economical efficiency by using highly concentrated isobutene. A method for preparing highly reactive polyisobutene comprises the steps of carrying out the polymerization by using a C4 mixture fraction containing 70 wt% or more of isobutene as a raw material to prepare polyisobutene; collecting the unreacted C4 mixture fraction not participating in the reaction to carry out the hydrogenation; and re-injecting the hydrogenated unreacted C4 mixture fraction into the raw material, thereby allowing the content of n-butene to be maintained to be 20 wt% or less.

Description

Method for preparing high-reactive polyisobutene using high concentrated isobutene

1 is a view schematically showing an apparatus for producing a highly reactive polyisobutene according to the present invention.

The present invention relates to a method for producing a highly reactive polyisobutene using a high concentration of isobutene, and more particularly, using a high concentration of isobutene, alpha olefin (hereinafter, vinylidene) in which the position of the carbon-carbon double bond is located at the terminal It relates to a method for producing a highly reactive polyisobutene having a content of at least 70% by weight.

Polybutene is generally a polymerized mainly isobutene in an olefin component having 4 carbon atoms (C4) using a Friedel-Craft type catalyst, and the number average molecular weight (Mn) is about 300 to 5000. Among them, polyisobutene is used to prepare lubricating oil additives or fuel additives by reacting with maleic anhydride or phenol, etc. In this case, high reactivity polyisobutene having high vinylidene content improves reactivity, thereby preparing high reactivity polyisobutene. How to get attention recently.

Conventionally, in the production of highly reactive polyisobutene, butane-butene fraction (BB fraction) generated during heavy oil catalytic cracking in petroleum refining process or C4 residue oil-1 (C4 raffinate) remaining after extracting 1,3-butadiene in naphtha pyrolysis process -1) was used as raw material. And, as a Friedel-Craft-type catalyst to such raw materials, a high-reactivity polyisobutene can be obtained by complexing a boron trifluoride catalyst with a cocatalyst (for example, water, alcohol, ether, etc.) (Korea Patent 667299, U.S. Patent 5,286,823, and the like. However, normal butenes such as 1-butene, trans-2-butene, cis-2-butene, etc. contained in the raw material of the highly reactive polyisobutene have a problem of lowering the vinylidene content because they participate in the polymerization reaction. In addition, normal butenes terminate the polymerization prematurely, thereby increasing the low molecular weight product, reducing the yield of the final product, and increasing the catalyst consumption.

In order to solve the above problem, high purity isobutene having an extremely small concentration of normal butene may be used as a raw material, but in order to prepare such high purity isobutene, methyl-t- may be selectively reacted by isobutene in methanol and C4 mixed fraction. After preparing and refining butyl ether, there is a disadvantage in that a complicated process and a high manufacturing cost are generated, such as re-decomposition and repurification of isobutene and methanol at high temperature again.

As a method for overcoming the above problem, in the process of preparing methyl ethyl ketone, butanol, maleic anhydride, propylene and the like using C4 residue as a raw material, high concentration of isobutene is obtained as a by-product. Here, the normal butene is separated from the C4 residue by isobutene by a catalytic distillation method using a boiling point difference. The separated isobutene is present at a high concentration of 70 to 95% by weight, and the normal butene is 2 to 3 parts as an impurity. 10% by weight. The high concentration isobutene separation method is known from Hydrocarbon processing, 58 (5), 112 (1979), Chemical Engineering, Feb., 13, p. 62 (1978) and the like. However, high concentration of isobutene of 70% by weight or more cannot be directly used as a polymerization raw material due to excessive reactant viscosity and heat of reaction. Therefore, by recycling the C4 mixed fraction from which isobutene has been removed and mixing it with a high concentration of isobutene raw material, it can be used as a polymerization raw material only after reducing the isobutene concentration to 50% by weight or less. However, this method has a problem that the normal butenes as impurities continue to accumulate, resulting in a decrease in the vinylidene content of the polyisobutene product as in the C4 residue.

Accordingly, an object of the present invention is to provide a method for producing high-reactivity polyisobutene, which has a lower catalyst consumption compared to the prior art and can significantly increase the yield by minimizing low molecular weight products.

It is still another object of the present invention to provide high-reactivity polyisobutene with a similar level of vinylidene content and more economically compared to the conventional method using high-purity isobutene obtained through methyl-t-butyl ether decomposition. It is to provide a method that can be produced.

In order to achieve the above object, the present invention collects the unreacted C4 mixed oil that does not participate in the reaction after the polymerization of polyisobutene using a C4 mixed oil having a content of isobutene of 70% by weight or more as a raw material Performing a hydrogenation reaction and re-injecting the hydrogenated unreacted C4 mixed fraction into the raw material, thereby maintaining the content of normal butene in the raw material at 20% by weight or less. To provide. Polyisobutene produced by the above production method has a vinylidene content of 70% by weight or more.

Hereinafter, the present invention will be described in detail.

C4 mixed oil having a content of isobutene of 70% by weight or more, which is used as a raw material in the present invention, is preferably (i) methyl ethyl ketone, butanol, using normal butene in C4 residue oil-1 produced by naphtha pyrolysis. By-products obtained in the process of preparing maleic anhydride, propylene and the like and (ii) a solvent for controlling the viscosity of the by-products are mixed. The by-product usually contains 70 to 95% by weight of isobutene, and 5 to 30% by weight of isobutane, n-butane, 1-butene, trans-2-butene, cis-2-butene and the like as the remaining components. The composition of high concentration isobutene obtained by separating normal butene by a conventional catalytic distillation method is shown in Table 1 below.

ingredient Content (% by weight) n-butane 1.5 Isobutane 4.6 1-butene 4.4 Isobutene 87.5 Trans-2-butene 1.7 Cis-2-butene 0.2

If such a high concentration of isobutene is directly polymerized without a solvent, normal production is not possible due to an increase in reactant viscosity and reaction heat. Therefore, in the present invention, C4 mixed fraction (hereinafter referred to as unreacted C4 mixed fraction) from which isobutene has been removed by polymerization of polyisobutene is used as a solvent, mixed with high concentration isobutene, and introduced into the polymerization reaction. At this time, as the number of circulation of unreacted C4 mixed fraction increases, the concentration of low reactivity normal butene increases. For example, a high concentration of isobutene, which is a reaction raw material, and an unreacted C4 mixed fraction circulated 10 times in a 1: 1 weight ratio. When mixed, the normal butene content is increased to 20% by weight or more, as shown in Table 2 below.

ingredient Content (% by weight) n-butane 7.5 Isobutane 21.0 1-butene 16.0 Isobutene 48 Trans-2-butene 5.8 Cis-2-butene 1.7

When the polyisobutene polymerization reaction is carried out using a raw material having a normal butene content of more than 20% by weight as shown in Table 2, the content of vinylidene decreases as a result of using the C4 residue as a raw material, thereby degrading the quality. Therefore, the present invention performs hydrogenation on the unreacted C4 mixed fraction recovered and recovered, thereby converting n-butene into n-butane in the unreacted C4 mixed fraction, and then mixing it with the raw material, thereby preparing a normal butene concentration in the raw material Is maintained at less than 20% by weight. As such, the present invention collects the unreacted C4 mixed fraction that does not participate in the reaction after the polymerization reaction, and is used as a reaction solvent for controlling the viscosity of the high concentration of isobutene, but undergoes the post-treatment of the hydrogenation reaction, It is characterized by maintaining the normal butene concentration to less than 20% by weight.

For the hydrogenation reaction, a palladium catalyst supported on ordinary silica or alumina may be used, and the catalyst has a palladium content of 0.1 to 0.5 wt%, and preferably a surface area of the carrier is 10 to 500 m ² / g. The reaction conditions are the reaction temperature of 0 to 200 ℃, preferably 10 to 100 ℃, the reaction pressure is 1 to 50 atm, preferably 3 to 30 atm, space velocity is 0.5 to 50 hr ^-1 , preferably 1 To 30 hr ⁻¹ .

The unreacted C4 mixed fraction may contain excess water mixed in the catalyst washing process after polymerization. Therefore, it is possible to remove the water using a conventional adsorbent such as silica, zeolite molecular sieve in the pre-hydrogenation step. The moisture content of the unreacted C4 mixed fraction treated with water adsorption is 200 ppm or less, preferably 5 to 100 ppm by weight.

The complex catalyst used in the polymerization of the polyisobutene of the present invention has a composition of the following formula (1).

[Formula 1]

(Boron trifluoride) _{0.5 to 1.0} (ether) _1-x (alcohol or water) _x

In Chemical Formula 1, x is 0.1 to 1, the ether is an aliphatic alkyl ether having 2 to 10 carbon atoms, and the alcohol is a straight or branched alcohol having 1 to 20 carbon atoms. Examples of the alkyl ethers include dimethyl ether, methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl isobutyl ether, diisobutyl ether, and the like. Ethanol, propanol, isopropyl alcohol, n-butanol, tert-butanol, iso- or n-nonanol and the like can be exemplified. The catalyst is charged in an amount of 0.1 to 50 mmol, preferably 0.5 to 10 mmol, based on boron trifluoride, relative to 1 mol of the isobutene component in the feedstock. If the amount of the catalyst is less than 0.1 mmol, the reaction does not proceed smoothly, and if the catalyst is used in excess of 50 mmol, the molecular weight and yield reduction are remarkable, and the catalyst cost and post-treatment burden are not preferable.

The reaction temperature of the polymerization reaction is -100 to 50 ℃, preferably -40 to 30 ℃. If the reaction temperature is less than -100 ℃, the reaction rate decreases is undesirable, and if it exceeds 50 ℃ side reactions such as isomerization of the carbon skeleton occurs, it is difficult to obtain the target product. The pressure of the polymerization reaction is from 0 to 50 atm, preferably from 3 to 20 atm under the condition that the reactant is maintained in the liquid phase.

The contact time of the catalyst and the feedstock in the polymerization reaction of the present invention is 5 minutes to 3 hours, preferably 10 minutes to 1 hour. If the contact time is less than 5 minutes, the conversion rate of the isobutene component is not sufficient. On the contrary, if the contact time is over 3 hours, the economic loss is large. . The conversion rate of the isobutene component is adjusted in the range of about 50 to 100% for the control of the molecular weight of polyisobutene.

In the present invention, in the step of collecting the unreacted C4 mixed fraction after the polymerization reaction, the reaction mixture may be further neutralized and washed with alkali and water to remove the catalyst used in the polymerization reaction from the organic phase. Here, as an alkali for neutralization and washing | cleaning, aqueous solution, such as sodium hydroxide, or gas, such as ammonia, can be used.

In addition, the present invention is to distill the reaction mixture after the polymerization reaction to separate the unreacted C4 mixed fraction and the isobutene polymer, and to collect the separated unreacted C4 mixed fraction, before the hydrogenation reaction, The zeolite molecular sieve or silica adsorbent can be used to remove the moisture content up to 200 ppm by weight.

The polyisobutene obtained by the method of the present invention has a number average molecular weight (Mn) of 300 to 5,000, a Mw / Mn value of 1.0 to 3.0 by measurement of gel permeation chromatography (GPC), and a vinylidene content of 70 More than%

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a view schematically showing a device for producing a highly reactive polyisobutene according to the present invention, first, C4 mixed oil containing at least 70% by weight of isobutene supplied through the pipe (6) is unreacted C4 After mixing with the mixed oil, the isobutene concentration is diluted to about 50% by weight and then fed to the polymerization reactor (1). When the polymerization reaction is completed, the reactants are supplied to the catalyst washing device 2 through the pipe 7 to remove the boron trifluoride catalyst contained in the reactants through neutralization and washing. The isobutene polymer from which the catalyst has been removed is fed to the unreacted C4 mixed fraction separation column 3 through a pipe 8. The unreacted C4 mixed oil is separated from the separation tower 3 and supplied to the water adsorption tower 4 through the pipe 9, and the isobutene polymer is transferred to the product purification process through the pipe 10. On the other hand, in the water adsorption tower (4) is absorbed and removed excess water in the unreacted C4 mixed fraction is transferred to the hydrogenation reactor (5) through the pipe (11). In the hydrogenation reactor 5, normal butene is converted into n-butane by adding hydrogen to the unreacted C4 mixed fraction. The unreacted C4 mixed fraction having the hydrogenation reaction is mixed with the original raw material 6 through the pipe 12 and then transferred to the polymerization reactor 1.

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by these examples.

[Production example]

The high concentration isobutene mixture obtained from the normal butene separation process and the unreacted C4 mixed fraction were mixed in a 1: 1 weight ratio, and the composition thereof is shown in Table 3 below.

Ingredient (% by weight) Isobutane n-butane 1-butene Isobutene C-2-butene T-2-butene High concentration isobutene 4.7 1.5 4.4 87.5 0.2 1.7 C4 mixed fraction (high concentration isobutene + unreacted C4) 21.0 7.5 16.0 48.0 1.7 5.8

Example 1

Under the 0.5 wt% palladium-supported alumina catalyst, the hydrogenation reaction was carried out at a reaction temperature of 60 ° C., a reaction pressure of 20 atm, and a space velocity of 2 hr ⁻¹ , using the C4 mixed fraction obtained in the preparation example as a reactant. The composition is shown in Table 4 below.

Example 2

Under the 0.5 wt% palladium-supported alumina catalyst, the hydrogenation reaction was carried out at a reaction temperature of 65 ° C., a reaction pressure of 20 atm, and a space velocity of 2 hr ⁻¹ , using the C4 mixed fraction obtained in the preparation example as a reactant. The composition is shown in Table 4 below.

Example 3

Under the 0.5 wt% palladium-supported alumina catalyst, the hydrogenation reaction was carried out at a reaction temperature of 70 ° C., a reaction pressure of 20 atm, and a space velocity of 2 hr ⁻¹ , using the C4 mixed fraction obtained in the preparation example as a reactant. The composition is shown in Table 4 below.

Ingredient (% by weight) Isobutane n-butane 1-butene Isobutene C-2-butene T-2-butene Example 1 20.8 18.9 7.6 47.9 1.1 3.6 Example 2 20.4 22.8 5.1 47.9 0.8 2.9 Example 3 19.5 27.5 2.8 47.8 0.3 2.0

Example 4-6 Preparation of Polyisobutene

Using the C4 mixed fractions obtained in Examples 1 to 3 as raw materials, the mixture was continuously introduced into a pressure reactor equipped with a cooling device, and the complex catalyst composed of boron trifluoride, isopropyl ether and water (molar ratio 1: 0.62: 0.62) was used. Boron trifluoride was injected in an amount of 0.21% by weight relative to ten. Reactor pressure is 3 atmospheres to keep the reaction material in the liquid phase Maintained above, the reaction temperature was controlled in the range of -25 to 10 ℃, the average residence time was to be 45 minutes. After 180 minutes of continuous reaction, the polymerization solution was taken directly from the reactor outlet into a vessel containing an aqueous sodium hydroxide solution to stop the polymerization. About 3 times of hexane was added thereto, washed with water three times to remove the catalyst, and finally stripped at 220 ° C. and 5 mm Hg for 30 minutes to remove the low boiling point polymerization liquid. The molecular weight of the obtained polybutene was measured by GPC, vinylidene content was analyzed using C ¹³ -NMR, the results are shown in Table 5 below.

division Reactant Reaction temperature (℃) Isobutene conversion (%) Molecular Weight (Mn) Vinylidene Content (%) Example 4 Example 1 -5 85.1 650 85 Example 5 Example 2 -10 83.7 970 86 Example 6 Example 3 -15 75.2 1,580 88

Comparative Example 1 Preparation of Polyisobutene

As a case where the unreacted C4 mixed oil was circulated without a separate treatment process, polyisobutene was prepared under the same reaction conditions as Example 4 using the C4 mixed oil prepared in Preparation Example as raw materials, and the analyzed results are shown in Table 6 below. Indicated.

division Reaction temperature (℃) Isobutene conversion (%) Molecular Weight (Mn) Vinylidene Content (%) Comparative Example 1 -10 85.1 940 81

Referring to Table 6, it can be seen that the comparative example without performing the hydrogenation reaction has a disadvantage in that the content of vinylidene is high due to the high content of normal butene in the polymerization raw material.

As described above, in the method for producing a highly reactive polyisobutene according to the present invention, in the production of polyisobutene using a C4 mixed fraction having an isobutene content of 70% by weight or more, unreacted C4 mixed after the polymerization reaction By circulating the oil through a hydrogenation process so that the content of normal butene in the polymerization reaction material is 20% by weight or less, a method for producing a highly reactive polyisobutene having a vinylidene content of 70% by weight or more is provided. It is more economical than the method using high purity isobutene, which is manufactured by -butyl ether synthesis and decomposition, as a raw material.

Claims (7)

After the polymerization of polyisobutene is carried out using C4 mixed oil having an isobutene content of 70% by weight or more as a raw material, hydrogenated reaction is performed by collecting unreacted C4 mixed oil not participating in the reaction, followed by hydrogenation. A method for producing a highly reactive polyisobutene comprising the step of re-injecting the unreacted C4 mixed fraction to the raw material, thereby maintaining the content of normal butene in the raw material to 20% by weight or less. The method of claim 1, wherein the C4 mixed fraction having an isobutene content of 70% by weight or more is prepared in the process of producing methyl ethyl ketone, butanol, maleic anhydride, or propylene using C4 residue oil-1 produced by naphtha pyrolysis as a raw material. A method for producing a highly reactive polyisobutene, which is a byproduct obtained. The method of claim 1, wherein the polyisobutene produced by the production method has a vinylidene content of 70% by weight or more. The method of claim 1, wherein the catalyst used for the hydrogenation reaction is a palladium catalyst supported on silica, a palladium catalyst supported on alumina, or a mixture thereof. The method of claim 4, wherein the catalyst has a palladium content of 0.1 to 0.5% by weight, and the surface area of the carrier is 10 to 500 m ² / g. The method of claim 1, wherein the hydrogenation reaction is performed at a reaction temperature of 0 to 200 ° C. and a pressure of 1 to 50 atmospheres at a space velocity of 0.5 to 50 hr ⁻¹ . The method of claim 1, wherein in the pre-hydrogenation step after collecting the unreacted C4 mixed fraction, the step of removing the water content to 200 ppm or less by weight using a zeolite molecular sieve or a silica adsorbent in the unreacted C4 mixed fraction is carried out. It further comprises a method for producing a high reactivity polyisobutene.

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