JP2000239319A - Production of butene polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a butene polymer having a low fluorine content and a high terminal vinylidene content by subjecting a specific raw material to a liquid phase polymerization by using boron trifluoride as a catalyst under a specific condition to provide the butene polymer having the high terminal vinylidene content, and treating the obtained butene polymer with a specified inorganic treating agent. SOLUTION: A supplied 4C raw material comprising <100 wt.% isobutene, 0.1-500 mmol boron trifluoride based on 1 mol isobutene, and 0.03-1,000 mmol complexing agent such as alcohols are continuously subjected to a liquid phase polymerization at (-100)-50 deg.C with 5 min to 4 hr retention time, and the catalyst in the reaction liquid discharged from the polymerization zone is deactivated. The reaction liquid after the deactivation of the catalyst, if necessary, is distilled to provide a butene polymer containing >=1 ppm residual fluorine and having >=60%; terminal vinylidene content, and the obtained butene polymer is treated with an alumina-containing inorganic material to reduce the residual fluorine concentration and to keep the terminal vinylidene content to >=60% of that before the treatment, and to provide the objective polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention uses a C ₄ feedstock and a boron trifluoride catalyst, is substantially free of fluorine remaining from the catalyst (hereinafter referred to as “residual fluorine”), and The present invention relates to a method for producing a butene polymer having a high content of a terminal vinylidene structure.

[0002]

2. Description of the Related Art U.S. Pat. No. 4,152,499 discloses that a polymer obtained by polymerizing isobutene using a boron trifluoride complex catalyst using water or alcohol as a complexing agent has a vinylidene structure. It is disclosed that this is a butene polymer containing a high proportion of the double bond form of the above, and that a high rate of maleation reaction proceeds with maleic anhydride or the like. Since the maleated polybutene produced in this manner is used as a fuel oil or a lubricant additive, the polybutene is released into the atmosphere by combustion or the like at the time of use or disposal. Here, when polymerizing using isobutene as a raw material, it is more economical to use a so-called C ₄ fraction containing n-butene and the like as a raw material than to use pure isobutylene as a raw material. However, when polymerizing the C ₄ fraction using a boron trifluoride complex as a catalyst, the resulting polymer contains fluorine due to the catalyst. As described above, the obtained polybutene is eventually burned and released to the atmosphere, so that the fluorine contained therein is also released to the atmosphere at the same time, and the fluorine sometimes causes air pollution. In recent years, there has been an increasing demand for environmental protection, and even small amounts of pollutants are regarded as problematic. In view of such circumstances, the present inventors have proposed many polymers as a post-treatment method for reducing residual fluorine in a polymer obtained by polymerizing a C ₄ fraction using a boron trifluoride complex as a catalyst. The method of removing fluorine was examined.

Here, a boron trifluoride complex is used as a catalyst to form C 3
It was confirmed that the fluorine in the polymer obtained by polymerizing the _four fractions was not only inorganic fluorine, but also some of which were bonded to the polymer chain as organic fluorine. Inorganic fluorine can be removed by washing with water, neutralization or the like, but organic fluorine cannot be completely removed by these conventional methods. Conventionally known adsorption or the like is not sufficient to remove such fluorine, and it is thought that it is necessary to remove fluorine by a elimination reaction of fluorine atoms from fluorocarbons. Therefore, it is necessary to search for a specific post-treatment method for removal for each polymerization reaction. For example, JP-A-57-
No. 183,726 proposes that the butene fraction is oligomerized with a nickel catalyst containing fluorine, and the fluorine contained in the obtained olefin trimer is specifically removed by treating it with silica gel. I have. However, as the later of the comparative example, when a boron trifluoride complex of C ₄ fraction polymerization to obtain the polymer as a catalyst, can not be sufficiently removed fluorine by treatment with silica gel. As a further problem, a phenomenon may occur in which the double bond in the polymer is isomerized during the treatment, and as a result, the content of the high terminal vinylidene bond obtained by the polymerization decreases. The isomerization (transfer) of a carbon-carbon double bond in a polymer is one type of chemical reaction.
Each may be promoted by a particular catalyst.

[0004]

The object of the present invention is to provide a boron trifluoride was polymerized C ₄ feedstock as a catalyst, by subjecting a content higher polymers obtained terminal vinylidene bonds to a post-processing step Another object of the present invention is to provide a butene polymer in which the content of the terminal vinylidene structure is maintained at 60% or more of the content before the treatment, and the residual fluorine in the polymer is reduced to a level that causes no practical problem.

[0005]

The first aspect of the present invention is to produce a butene polymer having a low fluorine content and a high terminal vinylidene content, which comprises the following steps (I) to (III). It is about the method. (I) of less than butene -1,50% by weight of less than 50 wt% butene -2,100 wt% less isobutene, _{C 4} feedstock comprising less than butanes less than 50 wt% and 10 wt% butadiene, the 0.1 to 500 mmol of boron trifluoride per mol of isobutene contained in the raw material, and 0.03 to 1,000 mmol of alcohol as complexing agent per mol of isobutene contained in the raw material And / or dialkyl ethers are respectively added to the polymerization zone, and the polymerization temperature is from -100 ° C to + 50 ° C.
And a continuous liquid phase polymerization for a residence time of 5 minutes to 4 hours. (II) After deactivating the catalyst in the reaction solution flowing out of the polymerization zone, if necessary, distillation is carried out.
butene polymer having a vinylidene terminal content of at least 60 ppm and a vinylidene terminal content of at least 60%, and then (III) reducing the residual fluorine concentration of the butene polymer and reducing the terminal vinylidene content to 60% of the content before the treatment. As described above, the butene polymer is treated with an inorganic treating agent containing alumina (hereinafter referred to as “alumina-containing inorganic substance”). The second aspect of the present invention relates to a method for producing a butene polymer having a residual fluorine content of less than 40 ppm after the step (III) in the first aspect of the present invention. The third aspect of the present invention relates to a method for producing a butene polymer according to the first aspect of the present invention, wherein the content of the terminal vinylidene structure after the step (III) is 70% or more of the content before the step (III). A fourth aspect of the present invention is that, in the first step (III) of the present invention, the contact temperature between the alumina-containing inorganic substance and the polymer containing residual fluorine is from 20 ° C to 220 ° C, preferably from 50 ° C to 200 ° C. And a method for producing a butene polymer. The fifth aspect of the present invention relates to a method for producing a butene polymer in which the average contact time between the alumina-containing inorganic substance and the polymer containing residual fluorine is 1 minute or more and less than 5 hours in the first step (III) of the present invention. .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, continuously polymerizing the C ₄ feedstock in the polymerization zone which includes a reactor (reaction zone). As the continuous reactor, any type such as a stirring type reactor and a loop type reactor can be adopted. From the polymerization zone, a reaction solution containing unreacted components and the produced butene polymer and catalyst flows out. C ₄ feedstock,
Less than 50% by weight of butene-1, less than 50% by weight of butene-2, less than 100% by weight of isobutene, less than 50% by weight of butanes and less than 10% by weight of butadiene (100% by weight in total) is there. The feedstock, in addition to isobutene, butene-1, a mixture of C ₄ hydrocarbons containing more than a certain amount of butene-2 and butadiene, for example, 5 weight butene-1, butene-2 and butadiene in a total % Is preferable.
Thus, in addition to isobutene, butene-1, butene-2
When polymerized by boron trifluoride complex catalyst of the C ₄ hydrocarbon feedstock containing a certain amount of equal is often unavoidable that a significant proportion fluorine atoms penetrating into the produced polymer.

[0007] Typical examples of the C ₄ hydrocarbon feedstock, there are so-called C ₄ fraction flowing out, for example, to produce ethylene and propylene, naphtha, kerosene, gas oil, crackers decomposes butane C _{A 4-} raffinate obtained by removing butadiene by extraction or the like is exemplified. C ₄ fraction typical composition of the unsaturated component, from about 1 to 40 wt%, preferably from about 10 to 40 wt%
About 1 to 40% by weight of butene-2 and about 10 to 80% by weight, preferably about 40 to 70% by weight of isobutene, about 10 to 30% by weight of butanes as a saturating component, and about 10% by weight of butanes. It consists of less than about 0.5% by weight butadiene, preferably less than about 0.5% by weight (100% by weight in total). Is not particularly limited as long as this is a composition range, it may be a C ₄ fraction containing isobutene contained in the decomposition product from the fluidized catalytic cracking (FCC) unit. In addition, those whose composition has been changed by appropriate means can also be used. Specifically, the composition is changed by distillation, the isobutylene concentration is increased by adding isobutylene, the isobutylene is oligomerized by light polymerization to reduce the isobutylene concentration, or butene is reacted by a reaction such as catalytic hydroisomerization. One having a reduced concentration or one whose composition has been modified by various physical or chemical operations can be used in the present invention as long as the composition is within the above-mentioned composition range. C ₄ fraction is preferably larger the isobutene content. However, the content of isobutene is, for example, up to about 70% by weight even in C ₄ raffinate. Usually lower the _{C 4} fraction from such FCC. Butadiene in the C ₄ fraction is about 0.5% by weight or less even when present, and is usually a trace amount of impurities. It is preferable that the water content of the raw material is usually adjusted to 10 ppm or less. However, the polymerization can be carried out without any particular problem even if about tens of ppm of water is contained.

[0008] As a catalyst used in the polymerization reaction, boron trifluoride is used. Boron trifluoride as a catalyst is fed into the polymerization zone at a ratio of 0.1 to 500 mmol per 1 mol of isobutene contained in the raw C ₄ hydrocarbon feed. The molecular weight of the polybutene obtained according to the present invention can be adjusted by adjusting the reaction temperature and the amount of the catalyst charged. If the amount of boron trifluoride as a catalyst is less than this range, the reaction does not easily proceed. On the other hand, if it is more than this range, many side reactions and the like occur, which is not preferable.

Further, alcohols, dialkyl ethers or mixtures thereof are used as complexing agents in a total amount of 0.03 to 1,000 mmol per 1 mol of isobutene contained in the C ₄ hydrocarbon feedstock. Add to polymerization zone. When the amount of the complexing agent is less than the above range, the reaction hardly proceeds. On the other hand, when the amount of the complexing agent is more than this range, many side reactions and the like occur, and both are not preferable. Here, any of the above-mentioned alcohols and dialkyl ethers can form a complex with boron trifluoride in the reaction system. Therefore, in the present invention, a method of separately preparing a complex of an alcohol, a dialkyl ether or a mixture thereof with boron trifluoride outside the reaction system and supplying the same to the reaction system is also adopted as one of the embodiments. can do. Even when the separately prepared complex catalyst is supplied to the reaction system, the supply ratio of the complex to the C ₄ hydrocarbon feed is converted into boron trifluoride as a complex component, alcohols and dialkyl ethers. , Respectively, within the above ranges.

When the complexing agent is present in a large amount in the system, it often acts as a polymerization inhibitor. Therefore, from the viewpoint of safety at the time of emergency stop, alcohols and dialkyl as the complexing agent are used. It is preferable to supply ethers or a mixture thereof to the reaction system separately from boron trifluoride. On the other hand, when preparing the complex in advance,
Since boron trifluoride is not used as a gas in the polymerization, handling is easy, and there are advantages such as requiring only one catalyst supply line. Depending on the circumstances, a pre-prepared complex may be used, or a method of separately supplying a complexing agent may be employed. In some cases, both methods can be employed simultaneously.

Alcohols and dialkyl ethers as more specific complexing agents are as follows. Examples of the alcohols include aromatic or C _{1 to} C ₂₀ aliphatic alcohols. Specifically, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol or benzyl alcohol, Cyclohexanol, 1,4-butanediol and the like.
The carbon skeleton of the C _{1 to} C ₂₀ alcohols is not limited in the degree of branching, and may be a linear alkyl group, a branched alkyl group such as sec- or tert- or an alicyclic alkyl group, or an alkyl group containing a ring. No problem. These alcohols
They can be used alone or mixed at an appropriate ratio.

Examples of the dialkyl ethers include aromatic or C _{1 to} C ₂₀ aliphatic dialkyl ethers having the same or different hydrocarbon groups. Specific examples include dimethyl ether, diethyl ether, methyl ethyl ether, and dialkyl ether. Examples thereof include propyl ether, methyl propyl ether, ethyl propyl ether, dibutyl ether, methyl butyl ether, ethyl butyl ether, propyl butyl ether, dipentyl ether, and phenyl methyl ether, phenyl ethyl ether, diphenyl ether, cyclohexyl methyl ether, cyclohexyl ethyl ether, and the like. The above C _{1 to} C
The skeleton of the hydrocarbon group No. ₂₀ is not limited in the degree of branching, and may be a linear alkyl group, a branched alkyl group such as sec- or tert- or an alicyclic alkyl group, or a ring-containing alkyl group. These dialkyl ethers can be used alone or in a mixture at an appropriate ratio. The above alcohols and dialkyl ethers can be used by mixing at an appropriate ratio as described above.

The polymerization in the step (I) is a liquid phase polymerization, and the temperature is -100 ° C to + 50 ° C, preferably -4 ° C.
It is in the range of 0 ° C to + 10 ° C. At a temperature lower than this range, the conversion of the olefin component of the liquid hydrocarbon containing isobutene is suppressed. On the other hand, when the temperature is higher than this, the conversion is suppressed and side reactions such as isomerization and rearrangement occur, which makes it difficult to obtain the target product of the present invention. Since the continuous method is economical and efficient from the viewpoint of industrial production, the polymerization is carried out continuously in the present invention.
In the continuous method, the contact time of the feedstock with the catalyst is important,
In the polymerization reaction according to the present invention, the contact time is preferably in the range of 5 minutes to 4 hours. If the contact time is less than 5 minutes, a sufficient conversion of the isobutene component cannot be obtained. Conversely, if the contact time is more than 4 hours, there is a large economical loss. All of these are not preferred because side reactions such as conversion and rearrangement are promoted. For good commercial profitability in the production of butene polymer, C ₄ fractions, for example, C ₄ conversion of isobutene component in the raffinate that higher is desired, be adopted polymerization conditions of the present invention It is possible to achieve an isobutene conversion of 80-100%.

After the polymerization, a reaction solution containing the unreacted components and the produced butene polymer and catalyst flows out from the polymerization zone as described above. In the step (II), the catalyst is deactivated with an appropriate deactivator, for example, water, alkaline water, alcohol, or the like, according to a conventional method with respect to the reaction solution. After deactivation of the catalyst, if necessary, neutralization and washing are performed to remove the catalyst residue, and distillation is performed appropriately to obtain a butene polymer.

As described above, the C ₄ hydrocarbon feedstock containing isobutene is subjected to liquid-phase polymerization using boron trifluoride as a polymerization catalyst, alcohol, dialkyl ether, or the like as a complexing agent, thereby obtaining a vinylidene terminal containing vinylidene. A butene polymer containing a high ratio of 60% or more can be obtained. However, this polymer contains residual fluorine derived from the catalyst at a concentration of 1 ppm or more, usually 5 ppm or more, for example, several tens of ppm. This residual fluorine is an organic fluorine which is difficult to remove even by deactivation and subsequent washing with water by a conventional method.

Next, in the present invention, in the step (III),
The obtained butene polymer is subjected to a defluorination treatment with an alumina-containing inorganic substance. In this step, when removing residual fluorine, it is important to maintain at least the high content of terminal vinylidene bonds. Specifically, the residual fluorine concentration is reduced so that the terminal vinylidene content maintains 60% or more, preferably 70% or more of the content before the defluorination treatment in this step. The butene polymer to be brought into contact with the alumina-containing inorganic substance in this step may be one after deactivation of the catalyst, and there is no limitation on the presence or absence of distillation after deactivation and water washing. When the viscosity is high, it is preferable to dilute with an inert solvent in order to increase the contact efficiency with the alumina-containing inorganic substance. As such an inert solvent, an aliphatic hydrocarbon solvent such as normal hexane and isohexane is preferable.

The defluorination temperature varies depending on the viscosity of the liquid and the type of the inorganic material containing alumina, but is preferably from 20 ° C. to 22 ° C.
0 ° C, more preferably 50 ° C to 200 ° C. If the processing temperature is higher than this range, the residual fluorine is reduced,
Isomerization of the terminal vinylidene proceeds to damage the terminal vinylidene structure, while isomerization does not occur at low temperatures,
Since the residual fluorine in the polymer is not reduced or a sufficient reduction effect cannot be obtained, none of the objectives can be achieved. Contact time is affected by viscosity and temperature, but ranges from about 1 minute to 5 hours. If the length is shorter than this range, the contact is insufficient, and if the length is longer, the equipment cost increases, which is not preferable.

The alumina-containing inorganic substance used is not particularly limited as long as it mainly contains alumina. silica·
Alumina can also be used. These can be appropriately impregnated with an alkali and an alkaline earth metal. However, it is usually sufficient to use alumina or the like having a content of an alkali metal such as sodium or an alkaline earth metal of 0.5% by weight or less. Also, from the industrial point of view of easiness of treatment, the alumina-containing inorganic substance is more preferably a molded article having a shape such as a sphere, a column, or a ring than a powder.

As a method of the defluorination treatment, a conventional method such as a fixed bed or a fluidized bed can be adopted. The contact is preferably carried out by a fixed bed flow system. When a solvent is used after the defluorination treatment, the butene polymer can be obtained by appropriate distillation. By recovering the butene polymer by the treatment in this step, the residual fluorine concentration is preferably reduced to less than 40 ppm, and the terminal vinylidene content is at least 60%, preferably 60% or less, of the value of the terminal vinylidene content before the treatment. A butene polymer held at a high value of 70% or more is obtained. This butene polymer is
Since the content ratio of the terminal vinylidene bond is high, the maleation reaction with maleic anhydride or the like proceeds at a high rate, which is useful. Further, since substantially no residual fluorine is present, even when the obtained butene polymer or its modified product is burned together with fuel, the emission of fluorine into the atmosphere is small, and therefore, it is useful from the viewpoint of environmental protection. is there.

Hereinafter, the present invention will be described specifically with reference to examples.

EXAMPLES <Example 1> (Production Step) 4 liters of circulating the reaction vessel, _{C 4} fraction (23.8 wt% of butene -1,12.4 wt% butene-2 and 51.6 % By weight of isobutene, 12.2% by weight of butanes as saturates and trace butadiene (100% by weight in total) are fed at a flow rate of 4 l / h and 0.15% by weight, based on isobutylene, Boron trifluoride and 0.14% by weight of ethanol were separately supplied to the reaction vessel. Reaction temperature is -10 ° C, L
Polymerization was carried out continuously with an HSV of about 1 hr ^-1 .

(Inactivation, washing step)
The catalyst was treated with an aqueous NaOH solution to deactivate and neutralize the catalyst, and then washed twice with deionized water. After washing, drying and distillation, the number average molecular weight is 1,300,
Terminal vinylidene content 91%, residual fluorine concentration 78ppm
Was obtained.

(Residual Fluorine Removal Step) Activated alumina (produced by PROCATALYSE, trade name: PSG-D25) dried under reduced pressure at 150 ° C. for 2 hours in a fixed-bed container having a capacity of 100 cc was changed from a particle size of 0.5 mm to 1.4 mm. Crushed and filled. The above-mentioned butene polymer diluted with an isoparaffin solvent so as to have a viscosity of 30 poise was passed through this filling vessel while changing the temperature and the WHSV, and a sample at the time of the oil passing multiple of 24 with respect to the filling volume was collected. The terminal vinylidene content and residual fluorine concentration of the polymer were measured. The number average molecular weight was determined by GPC (manufactured by Shimadzu Corporation).
Is used to determine the terminal vinylidene content by NMR (JEOL Ltd.)
And the residual fluorine concentration was measured by a Wickbold-colorimetric method. Table 1 shows the measurement results of the residual fluorine concentration and the terminal vinylidene content after the treatment.

[0023]

[Table 1]

Comparative Example 1 A butene polymer having a molecular weight of 1,800, a residual fluorine concentration of 130 ppm and a terminal vinylide content of 88% was diluted to 50% with normal hexane in order to increase the contact efficiency with silica gel. At this time, the viscosity of the liquid was 5 centipoise. This diluted polymer 1
27 g of silica gel (trade name: Silbead N, manufactured by Mizusawa Chemical Industry Co., Ltd.) preheated at 150 ° C. under a dry nitrogen stream was added to 00 ml, and the mixture was stirred at room temperature for 1 hour. After the treatment, the butene polymer had a terminal vinylidene content of 88% and a fluorine content of 66 ppm. Therefore, in the case of a butene polymer obtained by polymerizing a C ₄ fraction using a boron trifluoride complex as a catalyst, fluorine cannot be sufficiently removed even by treatment with silica gel.

[0025]

According to the method of the present invention, the content of terminal vinylidene bonds in the resulting butene polymer is high.
This is preferable because a high rate maleation reaction proceeds with maleic anhydride or the like. Further, since substantially no residual fluorine is present, even when a butene polymer or a modified product thereof is burned together with a fuel, the emission of fluorine into the atmosphere is small, which is useful in terms of environmental protection.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuichi Tokumoto 1733-3 Kagawa, Chigasaki-shi, Kanagawa F-term (reference) 4J100 AA04P AA05Q AA06R AS02S CA06 CA27 FA12 GA22

Claims (5)

[Claims] 1. A process for producing a butene polymer having a low fluorine content and a high terminal vinylidene content, comprising the following steps (I) to (III): (I) butene having a content of less than 50% by weight -1, less than 50% by weight butene-2,
Isobutene of less than 100% by weight, C ₄ feedstock comprising less than butanes less than 50 wt% and 10 wt% butadiene, relative to isobutene per 1 mole of contained in the raw material
0.1 to 500 mmol of boron trifluoride, and 0.03 to 1,1, mol of isobutene contained in the raw material
000 mmol of alcohols as complexing agents and / or
Alternatively, dialkyl ethers are respectively added to the polymerization zone, liquid phase polymerization is continuously performed at a polymerization temperature of -100 ° C to + 50 ° C and a residence time of 5 minutes to 4 hours, and (II) a reaction flowing out of the polymerization zone. After deactivating the catalyst in the liquid,
If necessary, distillation is carried out to obtain a butene polymer having a residual fluorine (hereinafter referred to as “residual fluorine”) of 1 ppm or more and a terminal vinylidene content of 60% or more, and then (III) measuring the residual fluorine concentration of the butene polymer. The butene polymer is treated with an inorganic treating agent containing alumina (hereinafter referred to as “alumina-containing inorganic substance”) so as to reduce the content and maintain the terminal vinylidene content at 60% or more of the content before the treatment. 2. The method for producing a butene polymer according to claim 1, wherein the residual fluorine content in the polymer obtained in the step (III) is less than 40 ppm. 3. The butene polymer according to claim 1, wherein the content of the terminal vinylidene structure in the polymer obtained in the step (III) is 70% or more of the content before the treatment in the step (III). Production method. 4. In the step (III), the contact temperature between the alumina-containing inorganic substance and the butene polymer containing residual fluorine is 20 ° C. or more and 220 ° C. or less, preferably 50 ° C.
The method for producing a butene polymer according to claim 1, which is at least 200 ° C. 5. The method for producing a butene polymer according to claim 1, wherein in step (III), the average contact time between the alumina-containing inorganic substance and the butene polymer containing residual fluorine is 1 minute or more and less than 5 hours.