JP6039971B2 - Olefin production method - Google Patents

Description

  The present invention relates to a method for producing an olefin, and more particularly to a method for producing a linear internal olefin having a double bond at a portion other than the end of a molecular chain by isomerization reaction of a linear α-olefin.

Internal olefins are useful intermediates used in paper sizing agent raw materials, surfactant raw materials, petroleum drilling oil base oils, lubricating oil base oils, lubricating oil raw materials, and chemical product raw materials.
As a method for producing such an internal olefin, a method using a Group 4 metal catalyst, specifically, a method using a specific titanium oxide catalyst supporting 4 to 6% by mass of sulfuric acid has been proposed (Patent Literature). 1).

US Patent Application Publication No. 2006/0100474

According to the method described in Patent Document 1, a linear internal olefin can be produced from a linear α-olefin, but the yield is reduced due to the production of branched or multimerized products by isomerization. Therefore, improvement is desired.
An object of this invention is to provide the manufacturing method of the linear internal olefin which can suppress by-products, such as a branched body and a multimer, and can obtain a linear internal olefin with a high yield.

When the present inventors examined the titanium oxide catalyst used for the isomerization reaction, it became possible to suppress side reactions by using a titanium oxide catalyst having a specific amount of sulfur under specific conditions. The present invention has been completed by finding that a chain internal olefin can be obtained in a high yield.
That is, the present invention
A method for producing a linear internal olefin in which an isomerization reaction of a linear α-olefin having 8 to 24 carbon atoms is performed in the presence of a titanium oxide catalyst, wherein the amount of sulfur contained in the titanium oxide catalyst is 0.34. A method for producing a linear internal olefin, wherein the isomerization reaction is a liquid phase reaction and the reaction temperature is 200 to 300 ° C.
Is a summary.

  According to the production method of the present invention, by-products such as branched and multimerized products can be suppressed, and a linear internal olefin can be obtained with a high yield.

In the method for producing a linear internal olefin of the present invention, an isomerization reaction of a linear α-olefin having 8 to 24 carbon atoms is performed in the presence of a titanium oxide catalyst, and the sulfur content contained in the titanium oxide catalyst is determined. The isomerization reaction is a liquid phase reaction, and the reaction temperature is 200 to 300 ° C.
In the present invention, the “liquid phase reaction” refers to a reaction in a state where a liquid exists at a temperature equal to or lower than the boiling points of the raw olefin and the product olefin at the pressure during the reaction.
Further, the linear internal olefin refers to an unsaturated aliphatic hydrocarbon having no branched chain and having a double bond at a portion other than the end of the molecular chain.

<Titanium oxide catalyst>
The titanium oxide catalyst is, for example, a method in which titanyl sulfate is hydrolyzed and precipitated, a method in which water is added to an alcohol solution of alkoxytitanium such as tetraisopropoxytitanium, and titanium halide such as titanium tetrachloride is vapor-phase oxidized. It can be obtained by a method or the like.
As the catalyst, a titanium oxide catalyst having a sulfur content of 0.34% by mass or less is used. When the sulfur content exceeds 0.34% by mass, the amount of by-products such as branched and multimerized products increases. The content of the sulfur content is preferably 0.0001% by mass or more, more preferably 0.002% by mass or more from the viewpoint of promptly proceeding with the isomerization reaction, and by-products such as branched products and multimers. From the viewpoint of suppressing the generation of, the content is more preferably 0.30% by mass or less, and further preferably 0.28% by mass or less.
Specifically, the content of sulfur is more preferably 0.0001 to 0.30% by mass, and further preferably 0.002 to 0.28% by mass.
Here, the sulfur content can be measured by a combustion ion chromatography method, and specifically can be measured by the method described in the examples.
In addition, when manufacturing from the raw material containing sulfur contents, such as a titanyl sulfate, for example, content of the sulfur content in a titanium oxide catalyst can be adjusted with the grade of washing | cleaning. As a raw material washing method, for example, the catalyst can be dispersed in a washing solvent such as water and then solid-liquid separation such as filtration and centrifugation. Titanium oxide containing a desired sulfur content can be obtained by adjusting the amount and frequency of the washing solvent.

  When preparing a titanium oxide catalyst from a raw material that does not contain sulfur, such as titanium tetrachloride and tetraisopropoxy titanium, impregnate the titanium oxide not containing sulfur with a sulfate such as sulfuric acid or ammonium sulfate, and then dry it. It is obtained by firing.

In the present invention, from the viewpoint of improving reaction activity and suppressing the formation of by-products, it is obtained by impregnating titanium oxide not containing sulfur with sulfuric acid or sulfate, followed by drying and further firing. It is preferable to use the obtained titanium oxide catalyst.
The crystal system of the titanium oxide catalyst may be any crystal system such as a rutile type, anatase type, or brookite type, but the anatase type is preferred from the viewpoint of promoting the isomerization reaction. The crystal system of titanium oxide can be confirmed by a known method such as powder X-ray diffraction.

From the viewpoint of improving the reaction rate, the specific surface area of the titanium oxide catalyst is preferably 10 m ² / g or more, more preferably 20 m ² / g or more, still more preferably 30 m ² / g or more, and even more preferably 40 m ² / g or more. It is preferably 800 m ² / g or less, more preferably 300 m ² / g or less, still more preferably 200 m ² / g or less, and even more preferably 150 m ² / g or less.
The specific surface area of the titanium oxide catalyst, specifically, preferably 10~800m ² / g, more preferably from 20 to 300 m ² / g, still more preferably ^{30~200m 2 / g, 40~150m 2 /} g Gayori Further preferred. The specific surface area can be determined by the BET method, and specifically can be measured by the method described in the examples.

The pore volume of the titanium oxide catalyst is preferably 0.05 ml / g or more, more preferably 0.1 ml / g or more, still more preferably 0.3 ml / g or more, and preferably 2.0 ml / g or less. 0.5 ml / g or less is more preferable, and 1.0 ml / g or less is still more preferable.
Specifically, the pore volume of the titanium oxide catalyst is preferably 0.05 to 2.0 ml / g, more preferably 0.1 to 1.5 ml / g, further 0.3 to 1.0 ml / g. preferable. When the pore volume of the titanium oxide catalyst is within the above range, the reaction rate is improved. The pore volume can be determined by mercury porosimetry, and specifically can be measured by the method described in the examples.

The shape of the titanium oxide catalyst may be any of powder, granulated product, and molded product, and examples thereof include granule, noodle, and pellet. The shape of the titanium oxide catalyst is a molded product in the form of granules, noodles, pellets, etc. from the viewpoint of solid-liquid separation in a suspension bed batch reaction and from the viewpoint of pressure loss reduction in a fixed bed continuous reaction. Is preferred. Further, the primary particle diameter of the titanium oxide catalyst is preferably 0.1 μm or more, more preferably 0.2 μm or more, further preferably 0.5 μm or more, and preferably 10,000 μm or less, more preferably 1,000 μm or less. 100 μm or less is more preferable.
Specifically, the primary particle diameter of the titanium oxide catalyst is preferably 0.1 to 10,000 μm, more preferably 0.2 to 1,000 μm, and still more preferably 0.5 to 100 μm.

The particle size can be appropriately selected from the viewpoint of improving the reaction rate and from the viewpoint of efficiently performing filtration during post-treatment. The particle size can be determined by a method such as a laser diffraction / scattering method.
The titanium oxide catalyst may be fixed on a carrier such as silica or diatomaceous earth.

<Raw material olefin (linear α-olefin)>
As the raw material olefin, a linear α-olefin (terminal olefin) having 8 to 24 carbon atoms is used. From the viewpoint of having a boiling point suitable for the reaction, the raw material olefin preferably has 10 to 22 carbon atoms, more preferably 12 to 18 carbon atoms.
Specific examples of the linear α-olefin include 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene and 1-heptadecene. 1-octadecene, 1-nonadecene, 1-icocene, 1-henicocene, 1-docosene, 1-tricosene and 1-tetracocene.
These linear α-olefins may be used alone or in combination of two or more. When a mixture of plural kinds of linear α-olefins is used, linear internal olefins having different alkyl chain lengths can be obtained.

Examples of the linear α-olefin include those derived from petroleum raw materials such as cracking, reforming and ethylene oligomerization, those derived from natural gas by MTG (Methanol To Gasoline) method, and decarbonylation from fatty acid derivatives of animal and vegetable oils. What was obtained by the method to perform, the thing obtained by dehydration reaction of 1-alcohol, etc. can be used conveniently.
The linear α-olefin may contain a linear internal olefin. The linear α-olefin used as a raw material already contains a linear internal olefin, but the reaction is performed in the presence of the titanium oxide catalyst, and the content is higher than the content of the linear internal olefin in the raw material. If so, it corresponds to the implementation of the present invention.

<Reaction conditions>
The reaction temperature is preferably 200 ° C. or higher, more preferably 220 ° C. or higher, further preferably 230 ° C. or higher, more preferably 300 ° C. or lower, and preferably 295 ° C. or lower from the viewpoint of suppressing the by-products and improving the yield. More preferred is 290 ° C. or lower.
Specifically, the reaction temperature is preferably 200 to 300 ° C, more preferably 220 to 295 ° C, and further preferably 230 to 290 ° C.
The production of a general internal olefin is carried out by a gas phase reaction from the viewpoint of suppressing the formation of multimers, but in the present invention, it is carried out by a liquid phase reaction. In the present invention, since a titanium oxide catalyst in which the sulfur content in the catalyst is defined within a specific range is used, it is possible to suppress the olefin from increasing even in a liquid phase reaction. A linear internal olefin can be obtained from a high-boiling olefin with low energy.

  The isomerization reaction in the production method of the present invention is preferably carried out in an inert gas atmosphere such as nitrogen or argon. By carrying out in the atmosphere of these inert gases, side reactions can be suppressed.

In the production method of the present invention, an organic solvent may be used as necessary. The organic solvent that can be used in the present invention is not particularly limited as long as it is liquid at the reaction temperature, is compatible with the substrate and the product, and does not inhibit the reaction, and may be a mixture. Moreover, what can isolate | separate from a product using a boiling point difference after reaction is preferable.
As the organic solvent that can be used in the present invention, hydrocarbon-based organic solvents such as saturated aliphatic hydrocarbons and aromatic hydrocarbons are preferable.

The saturated aliphatic hydrocarbon may be linear, branched or cyclic.
Specific examples of the saturated aliphatic hydrocarbon include compounds having 10 to 35 carbon atoms such as tridecane, hexadecane, octadecane, eicosane, docosane, triacontane, squalane and the like.
The saturated aliphatic hydrocarbon may be a mixture such as liquid paraffin, naphthene hydrocarbon, and isoparaffin hydrocarbon. Moreover, what is solid at normal temperature but liquid at the reaction temperature, such as solid paraffin, can also be used.
In addition, as the saturated aliphatic hydrocarbon, oligomers such as propylene and isobutene can be used.

  Specific examples of the aromatic hydrocarbon include alkylbenzene and alkylnaphthalene such as n-dodecylbenzene, n-tridecylbenzene, n-tetradecylbenzene, n-pentadecylbenzene, n-hexadecylbenzene, diisopropylnaphthalene and the like. .

In the production method of the present invention, either a suspension bed method or a fixed bed method may be employed.
The amount of titanium oxide catalyst used in the suspension bed method is preferably from 0.1 to 20% by mass, preferably from 0.3 to 15%, based on the linear α-olefin as the raw material, from the viewpoint of reaction rate and apparatus efficiency. % By mass is more preferable, and 1 to 10% by mass is even more preferable.

  In the case of the fixed bed method, the liquid space velocity varies depending on the reaction temperature and the sulfur content of the catalyst, but is preferably 0.05 to 15 / h, more preferably 0.1 to 10 / h, and 0.3 to 5 / h. Is more preferable. In the case of a fixed bed reaction, the catalyst is preferably granulated or molded from the viewpoint of ease of operation.

  The pressure during the reaction is preferably 0.01 to 1000 kPa because it is important that the substrate is in a liquid phase and the catalyst is uniformly wetted from the viewpoint of the reaction rate. The reaction time varies depending on the amount of catalyst used and the reaction temperature, but is usually 0.5 to 24 hours.

In the production method of the present invention, since the amount of branched products generated by isomerization of the skeleton is small, the amount of branched products generated relative to the raw material linear α-olefin can be suppressed to 5% by mass or less, preferably 4% by mass. Hereinafter, it can be suppressed to 3% by mass or less.
In addition, since the production method of the present invention has a small production amount of the multimer, the production amount of the multimer with respect to the raw material linear α-olefin can be suppressed to 5% by mass or less, preferably 4% by mass or less. More preferably, it can be suppressed to 3% by mass or less.
According to the production method of the present invention, the target linear internal olefin can be obtained in a yield of 90% by mass or more. Since the olefin obtained by the production method of the present invention has a low content of multi-branched bodies and multimers, it can be used as it is as a raw material for producing surfactants and the like. Further purification can be performed, but even in that case, the purification load is small.

  The reason why a linear internal olefin can be efficiently obtained while suppressing side reactions by the present invention is not clear, but by reducing the sulfate radical of the titanium oxide catalyst, a catalyst for side reactions such as branching and multimerization. It is considered that one of the causes is that the Brenstedt strong acid point is reduced.

  In the present invention, the internal olefin obtained as described above is useful as a raw material or an intermediate raw material for surfactants, organic solvents, softeners, sizing agents and the like.

In relation to the above-described embodiment, the present invention discloses the following method for producing a linear internal olefin.
<1> A method for producing a linear internal olefin in which an isomerization reaction of a linear α-olefin having 8 to 24 carbon atoms, preferably 10 to 22 carbon atoms, more preferably 12 to 18 carbon atoms is performed in the presence of a titanium oxide catalyst. The amount of sulfur contained in the titanium oxide catalyst is 0.34% by mass or less, preferably 0.0001 to 0.30% by mass, more preferably 0.002 to 0.28% by mass, and the isomerization. A method for producing a linear internal olefin, wherein the reaction is a liquid phase reaction and the reaction temperature is 200 to 300 ° C, preferably 220 to 295 ° C, more preferably 230 to 290 ° C.
<2> The method for producing a linear internal olefin according to <1>, wherein the titanium oxide catalyst is an anatase type.

<3> The method for producing a linear internal olefin according to <1> or <2>, wherein the titanium oxide catalyst is obtained by hydrolysis of titanyl sulfate.
<4> The titanium oxide catalyst is prepared by impregnating sulfuric acid or sulfate with respect to titanium oxide obtained by hydrolysis or vapor phase oxidation of titanium halide or alkoxy titanium. The manufacturing method of the linear internal olefin as described in 1> or <2>.

<5> The specific surface area of the titanium oxide catalyst is preferably 10 m ² / g or more, more preferably 20 m ² / g or more, still more preferably 30 m ² / g or more, still more preferably 40 m ² / g or more, and It is preferably 800 m ² / g or less, more preferably 300 m ² / g or less, further preferably 200 m ² / g or less, and still more preferably 150 m ² / g or less, according to any one of <1> to <4> A process for producing a linear internal olefin.
<6> The specific surface area of the titanium oxide catalyst is preferably 10~800m ² / g, more preferably 20 to 300 m ² / g, more preferably 30 to 200 m ² / g, even more preferably 40 to 150 m ² / The method for producing a linear internal olefin according to any one of <1> to <5>, which is g.

<7> The pore volume of the titanium oxide catalyst is preferably 0.05 ml / g or more, more preferably 0.1 ml / g or more, still more preferably 0.3 ml / g or more, and preferably 2.0 ml / g. The method for producing a linear internal olefin according to any one of <1> to <6>, which is g or less, more preferably 1.5 ml / g or less, still more preferably 1.0 ml / g or less.
<8> The pore volume of the titanium oxide catalyst is preferably 0.05 to 2 ml / g, more preferably 0.1 to 1.5 ml / g, still more preferably 0.3 to 1.0 ml / g. , <1>-<7> The manufacturing method of the linear internal olefin in any one.

<9> Any of <1> to <8>, wherein the amount of the olefin polymer produced relative to the linear α-olefin before the reaction is less than 5% by mass, preferably 4% by mass or less, more preferably 3% by mass or less. A process for producing a linear internal olefin according to claim 1.
<10> The production amount of the olefin having a branched chain with respect to the linear α-olefin before the reaction is less than 5% by mass, preferably 4% by mass or less, more preferably 3% by mass or less, <1> to <9> The manufacturing method of the linear internal olefin in any one of.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
<Quantitative determination of sulfur content>
The sulfur component was quantified by combustion ion chromatography under the following conditions.
(contents of the test)
A sample was collected in a sample container for combustion IC, added with tungsten oxide and mixed, and then introduced into combustion ion chromatography for measurement.
(Detailed conditions)
Sample collection amount: about 0.01 g
(Combustion conditions)
Model: Automatic sample combustion device, model number “AQF-100” (Mitsubishi Chemical Corporation)
Combustion furnace temperature: 1,000 ° C
Heating / burning time: 730 seconds [Using solid sample method]
Carrier gas; Ar
Combustion auxiliary gas: O ₂
At the time of combustion, a Ni-inner board was placed on the ceramic board, and tungsten oxide (about 5 times the amount of the specimen) was placed on the specimen, and the mixture was thoroughly mixed before burning.

(Ion chromatography conditions)
Model: ICS-1500 (DIONEX Corporation)
Detector; Electrical conductivity detector Separation column; IonPac AS12A 4mmID × 200mm
Guard column; IonPac AG12A 4mmID × 50mm
Suppressor; ASRS300 4mm (Recycle mode) (DIONEX Corporation)
Eluent: 2.7 mmol / L sodium carbonate and 0.3 mmol / L sodium bicarbonate
Thorium mixed eluent Eluent flow rate; 1.5mL / min
Calibration curve: Prepare a standard solution of 0.1, 0.5, 1.0, 5.0 μg / mL and perform calibration.
Created a line.

<Specific surface area / pore distribution measurement>
The BET specific surface area was measured using liquid nitrogen with a specific surface area measuring device (trade name “FlowSorb III” manufactured by Shimadzu Corporation).
The pore distribution was measured by mercury porosimetry using a mercury porosimeter. As the mercury porosimeter, trade name “AutoPore IV 9500” manufactured by Shimadzu Corporation was used.

^<1 H-NMR>
¹ H-NMR was measured using a product name “Mercury 400” manufactured by Varian as a measuring apparatus and deuterated chloroform as a solvent.

<Gas chromatography>
Gas chromatography was measured under the following conditions using “HP6890” manufactured by Agilent and “Ultra-Alloy-1” manufactured by FronterLAB.
Temperature rise condition: The temperature was raised from 100 ° C. to 350 ° C. at a rate of 12 ° C. per minute.
Hold at 50 ° C. for 5.2 minutes.
Carrier gas; helium flow rate; 19 mL / min inlet temperature; 300 ° C
Detector (FID) temperature: 350 ° C
Injection volume: 1 μL
Split; 20: 1
Internal standard substance: Dodecane

<Catalyst Preparation Example 1>
A 2 L separable flask was charged with 70 g of titanium tetraisopropoxide (manufactured by Wako Pure Chemical Industries, Ltd. (first grade)) and 800 g of ethanol. This solution was stirred with a mechanical stirrer (SUS turbine blade), and 600 g of ion-exchanged water was added dropwise over 1 hour. Thereafter, the mixture was further stirred for 1 hour, and the solvent was distilled off using an evaporator. The remaining solid was dried at 120 ° C. for 12 hours and then calcined at 500 ° C. for 3 hours. The obtained titanium oxide catalyst had a sulfur content of not more than the lower limit of quantification (10 ppm), the crystal system was anatase type, and the specific surface area was 87 m ² / g.

<Catalyst Preparation Example 2>
In a 2 L separable flask, 74 g of titanium tetraisopropoxide (Wako Pure Chemical Industries, Ltd. (first grade)) and 500 g of 2-propanol (Wako Pure Chemical Industries, Ltd. (first grade)) were charged. This solution was heated to 80 ° C. and stirred with a mechanical stirrer (SUS turbine blade) for 4 hours. Thereafter, 600 g of ion-exchanged water was added dropwise over 1 hour. And stirring was further performed for 1 hour. The remaining solid was collected by filtration, dried at 120 ° C. for 15 hours, and then calcined at 500 ° C. for 3 hours.
10 g of the obtained titanium oxide, 62.9 mg of ammonium sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 50 g of ion-exchanged water were charged into a 100 mL eggplant flask, and the solvent was distilled off using an evaporator. The remaining solid was dried at 120 ° C. for about 12 hours and then calcined at 500 ° C. for 3 hours. The obtained titanium oxide catalyst had a sulfur content of 0.15% by mass, a crystal system of anatase type, and a specific surface area of 35 m ² / g.

<Catalyst Preparation Example 3>
In a 200 mL eggplant flask, commercially available titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., titanium oxide (model number “CS200S”), sulfur content = 0.15% by mass) 9.7 g, ammonium sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.48 g and ion-exchanged water 50 g were charged. The solvent was distilled off from this using an evaporator. The remaining solid was dried at 120 ° C. for about 12 hours and then calcined at 500 ° C. for 3 hours. The obtained titanium oxide catalyst had a sulfur content of 1.3% by mass, a crystal system of anatase type, and a specific surface area of 55 m ² / g.

[Examples 1 to 7, Comparative Example 1]
Example 1
As a titanium oxide catalyst, 1.5 g of commercially available titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., model number “CS200S”, anatase type, sulfur = 0.15 mass%) ”was prepared, and this was combined with 1-octadecene (SIGMA- 50 g of Aldrich) was charged into a 100 mL four-necked flask. Nitrogen gas (50 mL / min) was circulated in the reaction vessel and stirred with a mechanical stirrer (half-moon stirring blade (diameter 40 mm), 500 rpm). The reaction vessel was heated with a mantle heater, and the reaction was carried out at 240 ± 10 ° C. for 5 hours, starting from the time when the internal temperature reached 240 ° C. The change in the composition of the reaction product was confirmed by ¹ H-NMR and gas chromatography. Table 1 shows the compositions 0.5 hours and 5 hours after the start of the reaction.

Example 2
The reaction was performed in the same manner as in Example 1 except that the catalyst was made by Sakai Chemical Industry Co., Ltd. and titanium oxide model number “CS300S” (anatase type, sulfur = 0.27%). Table 1 shows the compositions 0.5 hours and 5 hours after the start of the reaction.

Example 3
The reaction was performed in the same manner as in Example 1 except that the reaction temperature was 280 ° C. The composition after completion of the reaction is shown in Table 1.

Example 4
The reaction was carried out in the same manner as in Example 1 except that the catalyst prepared in the method of Catalyst Preparation Example 1 was used as the titanium oxide catalyst. The composition after completion of the reaction is shown in Table 1.

Example 5
The reaction was performed in the same manner as in Example 1 except that the reaction temperature was 200 ° C. and the catalyst amount was 10% by mass. The composition after completion of the reaction is shown in Table 1.

Example 6
The reaction was carried out in the same manner as in Example 1 except that the catalyst was a catalyst prepared by the method of Catalyst Preparation Example 2. The compositions after 0.5 hours and 5 hours after the reaction are shown in Table 1.

Example 7
The reaction was performed in the same manner as in Example 1 except that the reaction temperature was 200 ° C., the raw material was 1-dodecene (manufactured by Wako Pure Chemical Industries, Ltd.), and the catalyst amount was 7% by mass. The composition after completion of the reaction is shown in Table 1.

Comparative Example 1
The reaction was performed in the same manner as in Example 1 except that the catalyst was a catalyst prepared by the method of Catalyst Preparation Example 3. The composition after completion of the reaction is shown in Table 1.

  From the conversion rate of Examples 1, 2, and 6 after 0.5 hours, it can be seen that the catalyst of Catalyst Preparation Example 2 is more active.

The internal olefin selectivity can be calculated by the following calculation formula.
Internal olefin selectivity =
[(Terminal olefin conversion rate−branched product formation rate−dimer production rate) / terminal olefin conversion rate] × 100

  From Table 1, the manufacturing method of this invention can suppress by-products, such as a branched body and a multimer, and can obtain a linear internal olefin with a high yield.

Claims (7)

A method for producing a linear internal olefin in which an isomerization reaction of a linear α-olefin having 8 to 24 carbon atoms is performed in the presence of a titanium oxide catalyst,
The amount of sulfur contained in the titanium oxide catalyst is 0.34% by mass or less, the titanium oxide catalyst is obtained by hydrolysis of titanyl sulfate, and the isomerization reaction is a liquid phase reaction, The manufacturing method of the linear internal olefin whose reaction temperature is 200-300 degreeC. A method for producing a linear internal olefin in which an isomerization reaction of a linear α-olefin having 8 to 24 carbon atoms is performed in the presence of a titanium oxide catalyst,
The amount of sulfur contained in the titanium oxide catalyst is 0.34% by mass or less, and the titanium oxide catalyst is obtained by hydrolyzing or vapor phase oxidizing titanium halide or alkoxy titanium. A method for producing a linear internal olefin, which is prepared by impregnation with sulfuric acid or sulfate, wherein the isomerization reaction is a liquid phase reaction, and the reaction temperature is 200 to 300 ° C. The method for producing a linear internal olefin according to claim 1 or 2 , wherein the titanium oxide catalyst is of anatase type. The specific surface area of the titanium oxide catalyst is 10~800m ² / g, the production method of linear internal olefins according to any one of claims 1-3. The method for producing a linear internal olefin according to any one of claims 1 to 4 , wherein the titanium oxide catalyst has a pore volume of 0.05 to 2 ml / g. The amount of olefin multimers for linear α- olefin before reaction is less than 5 wt%, the production method of linear internal olefins according to any one of claims 1 to 5. The method for producing a linear internal olefin according to any one of claims 1 to 6 , wherein the production amount of the olefin having a branched chain with respect to the linear α-olefin before the reaction is less than 5% by mass.