Butene oligomer production method

Abstract

To provide a method with which it is possible to form, at a high conversion rate and high selectivity, a C12, C16 or C20 oligomer from at least one butene selected from 1-butene and 2-butene.SOLUTION: Provided is a butene oligomer production method, comprising an oligomerization step in which a C4 fraction that includes at least one selected from 1-butene and 2-butene and has an isobutene content of less than 3 mass% is brought into contact with a solid acid catalyst at 120-180°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing butene oligomers.

Background Art

[0002] Oligomers of butenes such as 1-butene, 2-butene, and isobutene are useful as components of solvents, fuels, and raw materials for chemical products. Among them, C 12 oligomers, C 16 oligomers, and C 20 oligomers are particularly used as solvents, diluents, lubricating oils, etc. As a method for oligomerizing isobutene, for example, a method of reacting isobutene in a C 4 fraction at 68°C in the presence of a silica-alumina catalyst is known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when butene is oligomerized, by-products having a carbon number that is not a multiple of 4 are likely to be generated. Such by-products cannot be reused as raw materials, and moreover, when such by-products are present, C 12 oligomers, C 16 oligomers, and C 20 oligomers are difficult to purify. In particular, 1-butene and 2-butene generally have a problem of lower reactivity than the above-mentioned isobutene. There is also a C 4 fraction containing a large amount of such 1-butene and 2-butene, and effective utilization of such a C 4 fraction is required.

[0005] The object of the present invention is to provide a method capable of oligomerizing one or more butenes selected from 1-butene and 2-butene with high conversion and high selectivity to C 12 、C 16 or C 20 oligomers.

Means for Solving the Problems

[0006] When the inventors studied the oligomerization of isobutene, no improvement in butene conversion was observed when oligomerization was carried out under high-temperature conditions of 120 to 180°C, and the total content of C 12 oligomers, C 16 oligomers, and C 20 oligomers in the product was rather reduced. However, as a result of intensive studies on the oligomerization of 1-butene and 2-butene by the inventors, when a C 4 fraction containing one or more selected from 1-butene and 2-butene and having an isobutene content of less than 3% by mass was brought into contact with a solid acid catalyst under high-temperature conditions of 120 to 180°C, surprisingly, it was found that C 12 、C 16 or C 20 could be oligomerized, and the present invention was completed.

[0007] That is, the present invention provides the following <1> to <6>. <1> A method for producing a butene oligomer, comprising an oligomerization step of bringing a C 4 fraction containing one or more selected from 1-butene and 2-butene and having an isobutene content of less than 3% by mass into contact with a solid acid catalyst at 120 to 180°C.

[0008] <2> The production method according to <1>, wherein the butene oligomer is represented by the following formula (1).

[0009]

Chemical formula

[0010] (In formula (1), A represents a structural unit derived from 1-butene, B represents a structural unit derived from 2-butene, n and m each represent an integer from 0 to 5, but are numbers that satisfy 2 ≤ n + m ≤ 5.)

[0011] <3> The production method according to <2>, wherein n and m in formula (1) each represent an integer from 0 to 5 and are numbers that satisfy 3 ≤ n + m ≤ 5. <4> The production method according to any one of <1> to <3>, wherein the reaction pressure in the oligomerization step is 1 to 8 MPa. <5> The production method according to any one of <1> to <4>, wherein the solid acid catalyst is a silica-alumina catalyst. <6> The production method according to any one of <1> to <5>, wherein the conversion rate of one or more selected from 1-butene and 2-butene in the oligomerization step is 90% or more.

Advantages of the Invention

[0012] According to the present invention, one or more butenes selected from 1-butene and 2-butene can be oligomerized with high conversion rate and high selectivity to C 12 , C 16 or C 20 .

Embodiments for Carrying Out the Invention

[0013] The method for producing a butene oligomer of the present invention includes an oligomerization step of bringing a C 4 fraction containing one or more selected from 1-butene and 2-butene and having an isobutene content of less than 3% by mass into contact with a solid acid catalyst at 120 to 180°C.

[0014] As used herein, "C 4 fraction" refers to a fraction mainly composed of hydrocarbons having 4 carbon atoms. As the total content of hydrocarbons having 4 carbon atoms, C 4In the fraction, 50% by mass or more and 100% by mass or less is preferable, 70% by mass or more and 100% by mass or less is more preferable, 90% by mass or more and 100% by mass or less is still more preferable, and 95% by mass or more and 100% by mass or less is particularly preferable. Examples of 2-butene include cis-2-butene and trans-2-butene. Either one of these may be used, or two of them may be used. From the viewpoint of suppressing by-products, etc., the total content of one or more selected from 1-butene and 2-butene is C 4 In the fraction, 30% by mass or more and 100% by mass or less is preferable, 40% by mass or more and 100% by mass or less is more preferable, and 45% by mass or more and 100% by mass or less is particularly preferable. The content of isobutene is C 4 In the fraction, it is less than 3% by mass. When the content of isobutene is 3% by mass or more, the amount of by-products that are not multiples of 4 in carbon number increases. From the viewpoint of suppressing by-products, etc., the content of isobutene is C 4 In the fraction, 0% by mass or more and 2.5% by mass or less is preferable, 0% by mass or more and 1% by mass or less is more preferable, and 0% by mass or more and 0.5% by mass or less is particularly preferable.

[0015] Also, from the viewpoint of suppressing by-products, etc., the total content of n-butane, isobutane and butadiene is C 4 In the fraction, 0% by mass or more and 60% by mass or less is preferable, 0% by mass or more and 55% by mass or less is more preferable, and 0% by mass or more and 50% by mass or less is particularly preferable.

[0016] As described above, C 4 As the fraction, for example, a fraction contained in the gas by-produced in naphtha cracking or fluid catalytic cracking is distilled (or reactive distillation) to contain one or more selected from 1-butene and 2-butene and the content of isobutene is less than 3% by mass. Also, prior to the oligomerization step, a pretreatment such as removing components that cause a decrease in catalyst activity may be performed on the C 4 fraction.

[0017] Examples of the solid acid catalyst used in the oligomerization step include catalysts containing Si and / or Al as inorganic oxides such as silica alumina, silica magnesia, silica boria, alumina boria, chlorinated alumina, fluorinated alumina, synthetic zeolite, etc., zirconia-based composite metal oxides such as molybdenum oxide / zirconia, tungsten oxide / zirconia, etc.; clay minerals such as acid clay, bentonite, kaolin, montmorillonite, etc.; cation exchange resins, heteropolyacids, and the like. These solid acid catalysts may be used alone or in combination of two or more. Among these, from the viewpoint of the conversion rate of 1-butene and 2-butene and the selectivity of C 12 , C 16 , C 20 oligomers, a catalyst containing Si and / or Al as inorganic oxides is preferred, a catalyst containing Si and Al as inorganic oxides is more preferred, and silica alumina is particularly preferred.

[0018] As the solid acid catalyst, a commercially available product or a product obtained by synthesis according to a conventional method may be used. Further, it is preferable that the solid acid catalyst is dried in advance. The drying method of the solid acid catalyst is not particularly limited, and examples thereof include a method of heating under reduced pressure or under the flow of dry air (or inert gas), a method of reflux treatment using a Dean-Stark trap, and the like. The drying temperature of the solid acid catalyst is usually 100 to 600 °C, preferably 130 to 500 °C. The drying time of the solid acid catalyst is usually 10 minutes to 48 hours, preferably 30 minutes to 24 hours.

[0019] The amount of the solid acid catalyst used is usually 1 to 30 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the C 4 fraction.

[0020] The reaction temperature in the oligomerization step is in the range of 120 to 180 °C. When the reaction temperature is less than 120 °C and more than 180 °C, the conversion rate of 1-butene and 2-butene and the C 12 oligomer, C 16 oligomer and C 20The total oligomer content is significantly reduced. The reaction temperature in the oligomerization step is the conversion rate of 1-butene and 2-butene, C 12 , C 16 , C 20 From the viewpoint of oligomer selectivity, it is preferably 130 to 180 °C, more preferably 140 to 180 °C, and particularly preferably 150 to 180 °C.

[0021] The reaction pressure in the oligomerization step is usually in the range of 1 to 8 MPa (absolute pressure, the same hereinafter), preferably in the range of 2 to 8 MPa. The reaction time in the oligomerization step is usually 5 minutes to 24 hours, preferably 15 minutes to 12 hours.

[0022] The oligomerization step can be carried out using an adiabatic reactor, a multitubular reactor, a fixed bed, a fluidized bed, or a moving bed flow reactor. Further, recycling of the reaction product to the reactor or dilution of the raw material with a diluent can also be carried out. Also, the reaction mode in the oligomerization step is not particularly limited, and any of a batch method, a semi-batch method, and a continuous flow method using a tank-type reactor may be used.

[0023] As the method for producing butene oligomer of the present invention, in addition to the oligomerization step, a distillation separation step of distilling and separating the unreacted C 4 fraction and the oligomer fraction in the reaction product may be further included. Further, in addition to the oligomerization step and the distillation separation step, from the oligomer fraction obtained in the distillation separation step, a butene oligomer in which n and m in the formula (1) each represent an integer of 0 to 5 and satisfy 3 ≤ n + m ≤ 5 may be further included.

[0024] The conversion rate of one or more selected from 1-butene and 2-butene in the oligomerization step is preferably 90% or more, more preferably 95% or more. C 12 oligomer, C 16 oligomer and C 20The total oligomer content is preferably 45% by mass or more, more preferably 49% by mass or more, and particularly preferably 55% by mass or more in the product of the oligomerization step.

[0025] According to the present invention, one or more butenes selected from 1-butene and 2-butene can be oligomerized with high conversion rate and high selectivity to C 12 C 16 or C 20 oligomers. In the present specification, "butene oligomer" refers to an oligomer derived from butene. According to the method for producing a butene oligomer of the present invention, an oligomer derived from one or more butenes selected from 1-butene and 2-butene can be produced.

[0026] Examples of the butene oligomer include those represented by the following formula (1).

[0027]

Chemical formula

[0028] 〔In formula (1), A represents a structural unit derived from 1-butene, B represents a structural unit derived from 2-butene, n and m each represent an integer from 0 to 5, but are numbers that satisfy 2 ≤ n + m ≤ 5.〕

[0029] The oligomer with n + m = 2 in formula (1) is a C 8 oligomer, the oligomer with n + m = 3 is a C 12 oligomer, the oligomer with n + m = 4 is a C 16 oligomer, and the oligomer with n + m = 5 is a C 20 oligomer. As n and m in formula (1), each represents an integer from 0 to 5, and numbers that satisfy 3 ≤ n + m ≤ 5 are preferred. Note that both ends of the butene oligomer are, for example, hydrogen atoms.

[0030] The butene oligomer obtained by the method for producing a butene oligomer of the present invention is useful, for example, as a raw material for diluents, lubricating oils, and detergents.

Examples

[0031] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0032] Each analysis condition in the examples is as shown below. <Method for Measuring Monomer Conversion Rate (Butene Conversion Rate) and Product Composition> The monomer conversion rate and the product composition were determined under the conditions shown in Table 1 below using GC ("SHIMAZDU GC-2014" manufactured by Shimadzu Corporation).

[0033]

Table 1

[0034] <C 4x <Method for Identifying Multimers (C 4x Oligomers)> C 8 、C 12 、C 16 The ranges of each component were calculated based on the product composition between the maximum and minimum values of the GC retention times of known compounds having the same number of carbon atoms (Table 2). The boiling range of the C 8 component was determined with reference to the retention times of diisobutylene and n-octene, and the boiling range of the C 12 component was determined between the retention times of isododecane and n-dodecane, and the boiling range of the C 16 component was determined between the retention times of isocetane and n-hexadecane. The range of the C 20 component was determined from the GC measurement results of the butene oligomerization reaction to be the corresponding range considered to be a pentamer product, and compounds with retention times above that were regarded as heavy components. The boiling points of each compound were based on known data. Also, regarding by-products within the ranges of the respective components described above, they were defined as being in the boiling point range of 69 to 101 °C in terms of the boiling point range conversion of hexane to diisobutylene, 125 to 177 °C in terms of the boiling point range conversion of n-octene to isododecane, and 216 to 240 °C in terms of the boiling point range conversion of n-dodecane to isocetane.

[0035]

Table 2

[0036] <Example 1> As a catalyst drying step, 4.2 g of a silica-alumina catalyst (“N633HN” manufactured by JGC Catalysts and Chemicals Ltd.) was introduced into a 160 mL pressure-resistant container and dried at 150 °C for 2 hours. Subsequently, as an oligomerization step, 50 g of 1-butene was introduced into the above reaction vessel, and a polymerization reaction was carried out by stirring for 6 hours under the conditions of a reaction temperature of 130 °C and a reaction pressure of 5 MPa. The butene conversion rate and the product composition are shown in Table 3.

[0037] <Examples 2 to 4, Comparative Example 1> The reaction was carried out in the same manner as in Example 1, except that the reaction temperature and the reaction pressure were as shown in Table 3. The results are shown in Table 3.

[0038] <Examples 5 to 8> The reaction was carried out in the same manner as in Examples 1 to 4, except that the raw material was changed to 2-butene (cis-2-butene: trans-2-butene = 1:2). The results are shown in Table 3. <Comparative Example 2> The reaction was carried out in the same manner as in Comparative Example 1, except that the raw material was changed to 2-butene (cis-2-butene: trans-2-butene = 1:2). The results are shown in Table 3.

[0039] <Comparative Examples 3 to 7> The reaction was carried out in the same manner as in Comparative Example 1 and Examples 1 to 4, except that the raw material was changed to isobutene. The results are shown in Table 3.

[0040]

Table 3

[0041] As shown in Table 3, in the isobutene oligomerization at a reaction temperature of 110°C (Comparative Example 3), when the reaction temperature was set to 120 - 180°C (Comparative Examples 4 - 7), no improvement in the butene conversion rate was observed, and the total content of C 12 oligomer, C 16 oligomer, and C 20 oligomer in the product rather decreased. On the other hand, in the 1-butene or 2-butene oligomerization at a reaction temperature of 110°C (Comparative Examples 1, 2), when the reaction temperature was set to 120 - 180°C (Examples 1 - 8), surprisingly, both the butene conversion rate and the total content of C 12 oligomer, C 16 oligomer, and C 20 oligomer in the product were significantly improved.

Claims

1. A process for producing butene oligomers, comprising an oligomerization step of contacting a C fraction containing at least one selected from 1-butene and 2-butene and having an isobutene content of less than 3% by mass with a solid acid catalyst at 120 to 180 °C. 4 ​

2. The production method according to claim 1, wherein the butene oligomer is represented by the following formula (1). 【Chemical 1】 〔In formula (1), A represents a structural unit derived from 1-butene, B represents a structural unit derived from 2-butene, n and m each represent an integer from 0 to 5, provided that 2 ≦ n + m ≦ 5.〕

3. The production method according to claim 2, wherein n and m in formula (1) each represent an integer from 0 to 5, and satisfy 3 ≦ n + m ≦ 5.

4. The production method according to any one of claims 1 to 3, wherein the reaction pressure in the oligomerization step is 1 to 8 MPa.

5. The production method according to any one of claims 1 to 4, wherein the solid acid catalyst is a silica-alumina catalyst.

6. The production method according to any one of claims 1 to 5, wherein the conversion rate of one or more selected from 1-butene and 2-butene in the oligomerization step is 90% or more.

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