Method for producing olefins and reactor for producing olefins

Abstract

This olefin production method comprises reacting an alcohol at 150°C or higher, in a liquid phase state, and in the presence of a metal oxide and sulfuric acid that is not supported on the metal oxide, the alcohol having 6-36 carbon atoms. The ratio of the mass of the sulfuric acid to the mass of the metal oxide is preferably 3-23%. The production method may be carried out by using a device comprising: a reaction tank in which the alcohol, the metal oxide, and the sulfuric acid can be stirred while heating; and a collection unit that cools and collects the generated olefin, the device also comprising, between the reaction tank and the collection unit, a moisture adsorption section that accommodates a moisture adsorbent.

Description

[Technical Field]

[0001] The present invention relates to a method for producing olefins and a reaction apparatus for producing olefins. This application claims priority under Japanese Patent Application No. 2023-136610, filed on 24 August 2023, and incorporates all the provisions of the said Japanese Patent Application. [Background technology]

[0002] Methods for obtaining olefins using the dehydration reaction of alcohols are known. For example, Patent Document 1 (Japanese Patent Application Publication No. 2013-203705) discloses a method for producing an internal olefin having a double bond inside an alkyl chain, using a long-chain aliphatic primary alcohol as a raw material. Patent Document 1 discloses the use of a composite oxide containing titanium dioxide and silicon dioxide and / or zirconium oxide as a catalyst, wherein the titanium dioxide content is 20 to 95 mol%.

[0003] Patent document 2 (Japanese Patent Publication No. 2014-224107) discloses a method for producing olefins using two or more alcohols with different numbers of carbon atoms as raw materials. Patent document 2 discloses the use of a solid acid catalyst as a catalyst, having a structure in which an acid such as sulfuric acid is supported on aluminum oxide, which is the support. Specifically, a solid acid catalyst is disclosed, which is a sintered body obtained by impregnating γ-alumina with water-diluted sulfuric acid and firing it at 500°C for 3 hours.

[0004] Patent document 3 (JP 2008-538206) discloses a method for producing olefins from alcohols using trifluoromethanesulfonic acid as a catalyst. The examples in patent document 3 describe a case in which dodecanol, tetradecanol, or other alcohols and trifluoromethanesulfonic acid are introduced into a distillation apparatus and heated at 240°C for several hours. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-203705 [Patent Document 2] Japanese Patent Publication No. 2014-224107 [Patent Document 3] Special Publication No. 2008-538206 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Patent documents 1 and 2 describe that the reaction temperature for producing olefins from alcohol can be set to approximately 200°C to 300°C. However, in practice, reaction temperatures of 260°C or higher are often used, and reactions at lower temperatures tend to require long reaction times or large amounts of catalyst. On the other hand, from the viewpoint of energy consumption, it is preferable to be able to produce olefins at low temperatures and in a short time. Therefore, one of the objectives of the present invention is to provide a method for producing olefins that can be carried out at a lower temperature range and in a shorter time compared to the prior art. [Means for solving the problem]

[0007] The method for producing olefins according to this disclosure is a method of reacting an alcohol having 6 to 36 carbon atoms in a liquid phase at a temperature of 150°C or higher in the presence of a metal oxide and sulfuric acid not supported on a metal oxide. [Effects of the Invention]

[0008] According to the above manufacturing method, a method for producing olefins is provided that can be carried out at a lower temperature and in a shorter time compared to conventional technologies. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an overview of the reactor used in the manufacturing method according to this disclosure. [Modes for carrying out the invention]

[0010] [Summary of the Embodiment] First, embodiments of the olefin production method according to this disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B".

[0011] The method for producing olefins according to this disclosure is a method of reacting an alcohol having 6 to 36 carbon atoms in a liquid phase at a temperature of 150°C or higher in the presence of a metal oxide and sulfuric acid not supported on a metal oxide.

[0012] Conventionally, various proposals have been made for the production of olefins from alcohols. For example, Patent Document 1 proposes a method for efficiently producing internal olefins having double bonds inside the alkyl chain. Patent Document 2 proposes a method for producing olefins in high yield while suppressing the increase in olefin volume. Patent Document 3 proposes a method for producing hydrocarbons that can be carried out under mild conditions and with almost no side reactions. On the other hand, due to demands for energy reduction and other factors, there is a need for a method that can efficiently produce olefins from alcohols at lower temperatures and in a shorter time than conventional methods.

[0013] In this regard, prior art also describes that the conversion reaction from alcohol to olefin can be carried out at temperatures of approximately 200°C or higher. However, when the reaction is carried out at temperatures of around 235-260°C, although the reaction occurs, it takes a long time, the reaction rate is insufficient, and a large amount of catalyst is required, so satisfactory results are not always obtained. In light of this situation, a method was investigated that can produce olefins from alcohol in high yield at a lower temperature range and in a shorter reaction time than conventional methods. It was found that by using a metal oxide and sulfuric acid not supported on a metal oxide as catalysts in the olefinization reaction, olefins can be obtained from alcohol in high yield in a short reaction time even at temperatures below 230°C.

[0014] In the manufacturing method, the mass ratio of the sulfuric acid to the metal oxide may be 3% or more and 23% or less. If it is within this range, the effects according to the present disclosure can be surely obtained.

[0015] In the manufacturing method, the alcohol may have 8 to 24 carbon atoms and may be a linear or branched primary alcohol or secondary alcohol. When obtaining an olefin using an alcohol within this range, the effects according to the present disclosure are clearer.

[0016] In the manufacturing method, the metal oxide may be one or more selected from the group consisting of oxides of elements selected from Groups 3 to 6 and Groups 12 to 13 of the periodic table. When using a metal oxide of the above-mentioned type, the effects according to the present disclosure are clearer.

[0017] In the manufacturing method, the metal oxide may be one or more selected from the group consisting of zirconium oxide, titanium oxide, aluminum oxide, silica alumina, tungsten oxide, scandium oxide, yttrium oxide, hafnium oxide, vanadium oxide, and niobium oxide. When using a metal oxide of the above-mentioned type, the effects according to the present disclosure are clearer.

[0018] In the manufacturing method, the total mass ratio of the metal oxide and sulfuric acid to the alcohol may be 0.5% or more. When it is within this range, while suppressing the cost of the olefin manufacturing method, the effects according to the present disclosure can be clearly obtained.

[0019] The reaction apparatus according to this disclosure is an apparatus for producing the olefin, comprising a reaction vessel capable of heating and stirring alcohol, a metal oxide, and sulfuric acid, and a collection unit for cooling and collecting the generated olefin, and a moisture adsorption unit containing a moisture adsorbent between the reaction vessel and the collection unit. With this reaction apparatus, it is possible to separate and recover the generated olefin from the alcohol, and also adsorb the generated moisture, allowing the reaction to proceed while removing moisture from the reaction vessel. As a result, the recovery of the olefin is easy, temperature control of the reaction vessel becomes easier, and olefin can be obtained efficiently while suppressing energy consumption.

[0020] The manufacturing method described herein is a method for obtaining olefins from alcohol using the aforementioned reaction apparatus. This manufacturing method makes it easier to recover olefins and allows for efficient production of olefins while suppressing energy consumption.

[0021] [Specific examples of embodiments] The method for producing the olefin according to this disclosure will be described in more detail below.

[0022] [catalyst] In the manufacturing method described herein, a metal oxide and sulfuric acid not supported on a metal oxide are used in combination in the production of an olefin. The metal oxide and sulfuric acid are thought to function as catalysts.

[0023] Examples of metal oxides include oxides of elements from groups 1 to 14 of the periodic table. Among these, oxides of elements selected from groups 3 to 6 and 12 to 13 of the periodic table are preferred. It is more preferable that the metal oxide has a valency of 3 or 4. Examples include zirconium oxide, titanium oxide, calcium oxide, yttrium oxide, aluminum oxide (alumina), silica-alumina (silicon oxide / aluminum oxide), zeolite, tungsten oxide, scandium oxide, yttrium oxide, hafnium oxide, vanadium oxide, niobium oxide, etc. Among these, oxides of elements selected from groups 4 and 13 of the periodic table are more preferred, and it is preferable that the metal oxide is one or more selected from the group consisting of zirconium oxide, titanium oxide, aluminum oxide, and silica-alumina. It is more preferable that the metal oxide is zirconium oxide. The metal oxide may also be a so-called composite metal oxide. Multiple types of metal oxides may be used in combination. When multiple types of metal oxides are used, it is preferable that the metal oxide contains zirconium oxide. The zirconium oxide content relative to the total amount of metal oxide is preferably 50 wt% or more, and more preferably 80 wt% or more.

[0024] The crystal structure and shape of the metal oxide used in the manufacturing method relating to this disclosure are not particularly limited. For example, the shape of the metal oxide may be powder, particles, pellets, or tablet-shaped molded products. 50 For example, the specific surface area is 0.01 μm or more and 100 μm or less, and preferably 0.02 μm or more and 10 μm or less. The specific surface area is not particularly limited, but for example, the BET specific surface area is 1 m 2 / g or more 300m 2 / g or less, 20m 2 / g or more 300m 2 / g or less, 20m 2 / g or more 150m 2 Preferably less than / g

[0025] The mass ratio of the metal oxide to the raw material alcohol is not limited as long as the effects described herein are obtained, but it should be 0.4% or more relative to the alcohol, preferably 1% or more, and more preferably 2% or more. If it is 0.4% or more, the catalytic effect can be exerted. There is no particular upper limit to the mass ratio of the metal oxide to the raw material alcohol, but adding it in excess does not increase the reaction efficiency, so in order to obtain olefins at a reasonable cost, it should be at most 25% or less, preferably 10% or less, and more preferably 5% or less.

[0026] Sulfuric acid can be any type commonly used in industry. It may be used undiluted, diluted with an alcohol having 5 or fewer carbon atoms such as water, methanol, ethanol, or propanol, or fuming sulfuric acid may be used. The mass ratio of sulfuric acid to the raw material alcohol is not limited as long as the effects described in this disclosure are obtained, but it should be 0.05% or more relative to the alcohol, preferably 0.1% or more, more preferably 0.14% or more, and even more preferably 0.2% or more. There is no particular upper limit on the mass ratio of sulfuric acid to the raw material alcohol, but since adding it in excess does not increase the reaction efficiency, to obtain olefins at a reasonable cost, it should be no more than 5%, and more preferably 0.5% or less. Typically, concentrated sulfuric acid with a concentration of 98% or more is used and preferably introduced into the reaction vessel in liquid form.

[0027] Furthermore, the mass ratio of sulfuric acid to the metal oxide is not limited as long as the effects described herein are obtained, but is preferably 3% or more, more preferably 4% or more, and even more preferably 10% or more. The mass ratio of sulfuric acid to the metal oxide is preferably 23% or less, more preferably 20% or less, and even more preferably 15% or less. If the sulfuric acid is 3% or more and 23% or less relative to the metal oxide, olefins can be efficiently produced.

[0028] The mass ratio of the catalyst (total amount of metal oxide and sulfuric acid) to the raw material alcohol is not limited as long as the effects described herein are obtained, but is 0.5% or more, and preferably 1% or more. There is no particular upper limit to the mass ratio of the catalyst to the alcohol, but from the viewpoint of reasonable cost, it is 26% or less, and preferably 6% or less. Hereinafter, the mass ratio of the catalyst added to the alcohol may be expressed as catalyst amount (%).

[0029] In the manufacturing method described herein, a metal oxide and sulfuric acid are used as catalysts, but the sulfuric acid is not supported on the metal oxide. An example of a state in which sulfuric acid is supported on a metal oxide is a so-called solid acid catalyst. Here, a solid acid catalyst means a composite in which a metal oxide supports sulfuric acid. Since solid acid catalysts are generally obtained by calcining a metal oxide impregnated with acid, the metal oxide and acid are added together. However, since the ratio of sulfuric acid to the metal oxide is easier to adjust to an appropriate range and the catalytic activity is higher when sulfuric acid is in a liquid state, it is preferable to add the metal oxide and liquid sulfuric acid separately. The metal oxide may be a metal oxide with acid supported (solid acid catalyst), or a combination of metal oxide and solid acid catalyst may be used. In the manufacturing method described herein, the reaction takes place in the presence of a metal oxide and sulfuric acid not supported on the metal oxide. There are no restrictions on the method of adding the metal oxide and sulfuric acid, and sulfuric acid and metal oxide may be used as materials to which they are added separately. Here, "added separately" is not limited to cases where the metal oxide and sulfuric acid are added separately when the catalyst is introduced into the reaction vessel, but also includes cases where the sulfuric acid and metal oxide are introduced into the reaction vessel in a pre-mixed state, or where the solid acid catalyst as a metal oxide and sulfuric acid are introduced into the reaction vessel.

[0030] [alcohol] The alcohol used in the manufacturing method according to this disclosure is an alcohol having 6 to 36 carbon atoms and is not limited as long as the effects according to this disclosure are obtained, but is typically a primary or secondary alcohol having 8 to 30 or 8 to 24 carbon atoms, and being linear or branched. The alcohol is preferably a monohydric alcohol. The alcohol may also contain cyclic hydrocarbon groups such as saturated alicyclic hydrocarbon groups and aromatic hydrocarbon groups. Examples of such alcohols include 1-hexanol, 1-octanol, 2-octanol, 2-methylheptanol, 6-methylheptanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 2-decyltetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, 1-eicosanol, 1-henicosanol, 1-docosanol, 1-tricosanol, 1-tetracosanol, 2-cyclohexylethanol, and 2-phenylethanol. Of these, the use of 1-hexanol, 1-octanol, 2-octanol, 1-decanol, 2-decanol, 1-dodecanol, 1-tetradecanol, 1-octadecanol, and 2-decyltetradecanol, which are alcohols that do not contain cyclic hydrocarbon groups, is particularly preferred because of the clear effect of efficiently obtaining olefins at low temperatures and in a short time. Only one type of alcohol may be used as the raw material, or two or more types may be combined.

[0031] The alcohol used in the manufacturing method according to this disclosure has a boiling point of 150°C or higher and 450°C or lower. In the method according to this disclosure, the alcohol is reacted in the liquid phase. When an alcohol with a boiling point of 150°C or higher and 450°C or lower is used as a raw material, it is easier to keep the alcohol in a liquid state in the reaction system, and the reaction can be carried out at atmospheric pressure or reduced pressure. Furthermore, for the reasons mentioned above, the alcohol used in the manufacturing method according to this disclosure is preferably one with a melting point of 150°C or lower.

[0032] [solvent] The manufacturing method described herein does not require the use of a solvent. However, a solvent, particularly an organic solvent, may be used as needed. The organic solvent is not particularly limited as long as it is liquid at the reaction temperature and does not inhibit the reaction. Examples of organic solvents include hydrocarbon organic solvents such as saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, and aromatic hydrocarbons. When an organic solvent is used, it is preferable that it can be separated from the product after the reaction by means such as utilizing the difference in boiling points.

[0033] Examples of saturated aliphatic hydrocarbons include compounds with 10 to 35 carbon atoms, such as tridecane, hexadecane, octadecane, eicosane, docosane, triacontane, and squalane. Alternatively, mixtures of saturated aliphatic hydrocarbons such as liquid paraffins, naphthenic hydrocarbons, and isoparaffinic hydrocarbons may be used.

[0034] Examples of unsaturated aliphatic hydrocarbons include eicosene, hexicosene, docosene, tricosene, and squalene. Unsaturated aliphatic hydrocarbons may be mixtures. Examples of aromatic hydrocarbons include alkylbenzenes and alkylnaphthalenes such as n-dodecylbenzene, n-tridecylbenzene, n-tetradecylbenzene, n-pentadecylbenzene, n-hexadecylbenzene, and diisopropylnaphthalene.

[0035] [Other ingredients] In the manufacturing method relating to this disclosure, other components may be used in addition to the above-mentioned components, as long as the effects relating to this disclosure are obtained. Examples of other components include dehydrating agents and water.

[0036] [Manufacturing method] The manufacturing method according to this disclosure is a method for producing olefins, in which an alcohol having 6 to 36 carbon atoms is reacted in a liquid phase at 150°C or higher in the presence of a metal oxide and sulfuric acid not supported on a metal oxide, and specifically includes, for example, a first step of preparing an alcohol having 6 to 36 carbon atoms, a metal oxide and sulfuric acid not supported on a metal oxide, and a second step of introducing the alcohol, the metal oxide and sulfuric acid prepared in the first step into a reaction vessel and holding the alcohol at 150°C or higher and in a liquid state in the presence of the metal oxide and sulfuric acid not supported on a metal oxide.

[0037] The first step is a preparation step. In the first step, alcohol as a raw material, a metal oxide as a catalyst, and sulfuric acid not supported on the metal oxide are prepared. In the manufacturing method according to this disclosure, in addition to these essential materials, organic solvents, dehydrating agents, water, etc. may be used as needed.

[0038] The second step is a reaction step to carry out olefinization. The reaction is carried out in the liquid phase in the presence of a metal oxide and sulfuric acid not supported on the metal oxide. Alcohol, metal oxide, and sulfuric acid are added to the reaction vessel. It is sufficient that the metal oxide and sulfuric acid not supported on the metal oxide are present in the reaction step, and there are no restrictions on how the metal oxide and sulfuric acid are added. For example, the metal oxide and sulfuric acid may be added separately, or they may be added after being mixed beforehand. The metal oxide may also be added in the form of a solid acid catalyst. Next, the temperature is raised to a predetermined temperature and the reaction is carried out.

[0039] The reaction temperature can be below the boiling point of the raw material alcohol. If the reaction is carried out at a temperature above the boiling point of the raw material alcohol, the reaction may be carried out under pressure to maintain the raw material alcohol in a liquid state. The specific reaction temperature can be selected depending on the type of raw material alcohol, but it may be 150°C or higher, preferably 170°C or higher, and more preferably 200°C or higher. Furthermore, from the viewpoint of energy efficiency and equipment load, it may be 300°C or lower, preferably 270°C or lower, and more preferably 240°C or lower. From the viewpoint of energy saving, a lower reaction temperature is preferable, but a reaction temperature in the range of 210°C to 250°C is preferable because it provides high reaction efficiency. In the manufacturing method according to this disclosure, by using the above-mentioned catalyst, olefins can be obtained in a short time even at around 230°C.

[0040] The reaction pressure may be atmospheric pressure, or it may be carried out under reduced pressure or increased pressure as needed. When the reaction is carried out under reduced pressure, the pressure can be, for example, 0.001 MPa to 0.09 MPa. The pressure can also be changed during the second step. By controlling the pressure, it is also preferable to distill and separate the olefin product from the raw material alcohol.

[0041] The reaction apparatus may be kept under an inert gas atmosphere. Examples of inert gases that can be used include nitrogen gas and argon gas.

[0042] The reaction time can be selected depending on the reaction temperature, type and amount of catalyst used, etc., but for example, it is 0.5 hours or more and 10 hours or less, preferably 1 hour or more and 7 hours or less, and more preferably 2 hours or more and 5 hours or less. According to the manufacturing method of this disclosure, it has been confirmed that olefinization proceeds even with a reaction of 2.5 hours at a temperature of about 230°C.

[0043] According to the manufacturing method of this disclosure, the alcohol conversion rate is 25% or more, preferably 30% or more, more preferably 60% or more, and even more preferably 90% or more. The alcohol conversion rate (%) is 100 - (ratio of the amount of alcohol present in the liquid after the reaction).

[0044] According to the manufacturing method of this disclosure, a higher proportion of olefin in the recovered product after the reaction is desirable because it results in fewer by-products such as ethers and polymers. The proportion of olefin is 5% or more, preferably 15% or more, more preferably 30% or more, even more preferably 50% or more, and most preferably 75% or more.

[0045] The olefins obtained by the manufacturing method according to this disclosure typically contain 1-15% α-olefins and 85-99% internal olefins. Furthermore, these olefins also contain 1-15% branched-chain olefins. Because the olefins obtained by the manufacturing method of the present invention contain a large amount of internal olefins, they can be suitably used as raw materials or intermediate raw materials for lubricants, surfactants, and the like.

[0046] In the manufacturing method according to this disclosure, it is preferable to carry out the reaction while separating the olefin from the alcohol by utilizing the difference in boiling points between the alcohol and the olefin produced from the alcohol. By reacting in this manner, the formation of polymers of the olefin, which are by-products, can be suppressed. Distillation can be used as a method of separation. At the same time, in order to suppress the temperature drop of the reaction vessel, it is preferable to carry out the reaction while separating the water produced as a result of the dehydration of the alcohol. As a method of separation, for example, water can be adsorbed using a water adsorbent.

[0047] [Reaction apparatus] Figure 1 shows an example of a reaction apparatus used in the manufacturing method according to this disclosure. The reaction apparatus has a distillation column at the top of the reaction vessel. Alcohol, a raw material, a metal oxide catalyst, and sulfuric acid not supported on a metal oxide are introduced into the reaction vessel 1. The reaction vessel 1 is equipped with a stirrer 10. A thermometer 11 is inserted into the reaction vessel 1 to detect the temperature inside the reaction vessel. The reaction vessel 1 is heated using a heating device (not shown). A cylindrical section 2, which serves as a moisture adsorption section for containing a moisture adsorbent 6, is provided at the top of the reaction vessel 1. The cylindrical section 2 has side tubes 12. As the moisture adsorbent 6, known moisture adsorbents such as molecular sieves (crystalline zeolite) can be used. The water generated in the reaction vessel 1 during the dehydration reaction, which is the conversion of alcohol to olefin, diffuses upward from the reaction vessel 1 as water vapor because the temperature inside the reaction vessel 1 is above the boiling point of water. The water vapor is cooled in cooling sections 3 and 9, turns into water, and flows back into the cylindrical section 2, where it is adsorbed by the water adsorbent 6. In this way, water is separated from the reaction vessel 1.

[0048] Cooling sections 3 and 9 are provided at the top of the cylindrical section 2. In the example in Figure 1, two stages of cooling sections 3 and 9 are provided, but a single cooling section or multiple stages of cooling sections may be used as needed. Cooling section 4 branches off from between cooling sections 3 and 9. A collection container 5 is provided at the end of cooling section 4. A pump 13 is provided between cooling section 4 and collection container 5 via a branch pipe 8. The pump 13 can be used to increase or decrease the pressure within the reaction system as needed.

[0049] The olefin produced in the reaction has a lower boiling point than the alcohol used as a raw material. This difference in boiling points allows the olefin to be recovered by distillation. Specifically, the olefin in a gaseous state is cooled in the cooling unit 4, and the olefin can be collected as a liquid in the collection container 5. The cooling unit 4 and the collection container 5 constitute the olefin collection unit.

[0050] According to the reaction apparatus shown in FIG. 1, while separating the generated olefin by distillation, water generated along with the dehydration of alcohol can be quickly removed from the reaction tank, and reflux of water into the reaction tank can be suppressed. For this reason, it becomes possible to recover highly pure olefin, temperature control becomes easier, and energy consumption required for the reaction can also be suppressed.

[0051] In addition to the above-described reaction apparatus, after reacting alcohol with a reaction apparatus without providing a distillation column at the upper part of the reaction tank, the reaction solution is taken out from the reaction apparatus, and the olefin generated by solid-liquid separation and distillation can also be recovered. Further, a reaction apparatus may be used in which a metal oxide is filled in a tubular container, and alcohol added with sulfuric acid is flowed through the tubular container filled with the metal oxide to react the alcohol, and then the olefin is recovered by distillation. From the viewpoints of energy efficiency and reaction efficiency, it is preferable to use a reaction apparatus having a distillation column at the upper part of the reaction tank.

[0052] [Examples] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0053] [Measurement and calculation methods] 1. NMR In some of the following examples and comparative examples, nuclear magnetic resonance (NMR) was used to confirm the conversion rate of alcohol and the abundance ratio of olefin in the recovered product after the reaction. Under the following measurement conditions 1 1H-NMR measurement was performed. Measurement conditions · Apparatus: JNM-ECX series FT NMR apparatus manufactured by JEOL Ltd., 400 MHz · Solvent: chloroform-d · Conditions: number of scans 16 times, room temperature Since the recovered product was separated into a distillate and a residual liquid (bottom residue) in the reaction vessel, for each of them 1¹H-NMR measurements were performed. In the resulting NMR chart, peaks originating from alcohol, olefins, and by-product polymers and ethers were identified. The relative abundance of olefins and alcohols in the recovered product, as well as the conversion rate of alcohols, were calculated from the area ratio of each peak and the number of protons originating from each peak. The relative abundance (%) of olefins and alcohols and the conversion rate (%) of alcohols in the total recovered product were calculated using the following formulas. Olefin content ratio (%) of total recovered material = (Olefin content ratio of distillate (%) × Distillate yield / Total yield) + (Olefin content ratio of still liquid (%) × Still liquid yield / Total yield) ... Equation (1) The percentage of alcohol in the total recovered material (%) = (Percentage of alcohol in the distillate (%) × Yield of the distillate / Total yield) + (Percentage of alcohol in the still residue (%) × Yield of the still residue / Total yield) ... Equation (2) Alcohol conversion rate (%) = 100 - (Alcohol content of distillate (%) × Distillate yield / Total yield) + (Alcohol content of still liquid (%) × Still liquid yield / Total yield) ... Equation (3)

[0054] 2.GC In the following examples and comparative examples, gas chromatography (GC) was used to (i) confirm the conversion rate of alcohols, (ii) confirm the relative abundance of olefins in the recovered product after the reaction, and (iii) identify the olefins. Samples for (i) and (ii) were prepared by diluting the recovered product with hexane and then filtering it. The measurements were performed under the following conditions. Measurement conditions • Equipment: SHIMADZU GC-2010Plus • Column: Frontier Laboratories Ltd. Ultra ALLOY Capillary Column UA17-15W-0.25F (30m x 0.250mm, 0.10 Micron) • Evaporation chamber temperature: 350℃ ·Injection method: Whole amount injection method • Carrier gas: Nitrogen (Column flow rate: 1.48 mL / min) Temperature conditions: 50°C to 350°C, heating at 12.5°C / min, then holding at 350°C for 15 minutes. Based on the area of ​​the peaks representing olefins, alcohols, and by-products (polymers and ethers) in the obtained GC chart, the relative abundance of olefins and alcohols, as well as the conversion rate of alcohols, were calculated. Furthermore, if the recovered material was separated into distillate and residual liquid in the reaction vessel (still liquid), GC analysis was performed on each to calculate the relative abundance of olefins and alcohols and the conversion rate of alcohols. Then, using the calculated results and the above-mentioned equations (1) to (3), the relative abundance of olefins and the conversion rate of alcohols to the total recovered material were calculated. (iii) Identification of olefins (determination of the position of the double bond in the olefin) was evaluated by reacting the olefin obtained by the production method of the present invention with dimethyl disulfide to obtain a dithiolated derivative, and separating the components by GC. The peaks of the obtained GC chart were compared with the GC peaks of dithiolated olefins with known structures to identify the position of the double bond in the olefin obtained by the production method of the present invention. Based on the area of ​​each peak, the relative abundance of each generated olefin was calculated. The measurements were performed under the same conditions as in (i) and (ii).

[0055] [Comparative Example 1] The reaction was carried out using the apparatus outlined in Figure 1. 200 g of 1-dodecanol (Kao Corporation, Calcol® 2098) and 4 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100) were added to a 500 mL four-necked flask and stirred at 250 °C for 5 hours under a nitrogen atmosphere. Water was supplied to the cooling unit 3, but there was no reflux and distillation was not possible. Therefore, 200 g of the brown, turbid liquid (100% yield) in the flask was recovered, and the component ratios (ratio of olefins and alcohols) and the conversion rate of alcohols in the recovered material were evaluated by GC.

[0056] [Example 1] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 6 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.3 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C for 2.5 hours under a nitrogen atmosphere. Water was supplied to the cooling unit 3, but there was no reflux and distillation was not possible. Therefore, 279 g of the brown, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered product were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0057] [Example 2] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 6 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.43 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230°C for 0.5 hours under a nitrogen atmosphere. The components cooled in cooling unit 3 refluxed. Subsequently, the water supply to cooling unit 3 was stopped, and the product was recovered by distillation by stirring at 230°C for 2 hours. The recovered product was treated with sodium sulfate to adsorb water from the recovered material. After the adsorption treatment, 157 g of a colorless, transparent liquid was obtained. In addition, 51 g of the brown, turbid liquid remaining in the flask was recovered. The product and residual liquid recovered by distillation were measured by GC, and the component ratios relative to the total recovered material and the conversion rate of alcohol were calculated using the formula described above. The formation of a C12 monoolefin was confirmed by GC.

[0058] [Example 3] The reaction and evaluation were carried out in the same manner as in Example 2, except that the amount of sulfuric acid was changed to 0.53 g. 159 g of a colorless, transparent liquid was recovered by distillation, and 43.81 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 2. The formation of a C12 monoolefin was confirmed by GC.

[0059] [Example 4] The reaction and evaluation were carried out in the same manner as in Example 2, except that the amount of sulfuric acid was changed to 0.6 g. 166 g of a colorless, transparent liquid was recovered by distillation, and 44 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 2. The formation of a C12 monoolefin was confirmed by GC. The olefins formed were identified by GC by reacting them with dimethyl disulfide. The resulting olefins were 1-dodecene 2.1%, trans-2-dodecene 12.9%, cis-2-dodecene 6.6%, trans-3-dodecene 13.8%, cis-3-dodecene 4.7%, trans-4-dodecene 15.6%, cis-4-dodecene and trans-5-dodecene 26.9%, cis-5-dodecene and 6-dodecene 7.2%, and branch-dodecene 10.2%.

[0060] [Example 5] The reaction and evaluation were carried out in the same manner as in Example 2, except that the amount of sulfuric acid was changed to 1.2 g. 113 g of a colorless, transparent liquid was recovered by distillation, and 104 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 2. The formation of a C12 monoolefin was confirmed by GC.

[0061] [Comparative Example 2] The formulation was the same as in Example 4, except that zirconium oxide was not added, and the mixture was stirred at 230°C for 2.5 hours. Water was supplied to the cooling unit 3, but there was no reflux and distillation was not possible, so 294 g of liquid was recovered from the flask, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC measurement.

[0062] Table 1 summarizes the catalyst composition, reaction conditions, and analysis results of the recovered products in Examples 1-5 and Comparative Examples 1 and 2. [Table 1]

[0063] As shown in Table 1, in Examples 1-5, zirconium oxide and sulfuric acid were used as catalysts, and olefins were obtained at a reaction temperature of 230°C for 2.5 hours. In particular, in Examples 2-5, where the mass ratio of sulfuric acid to the metal oxide was 6% to 20%, olefins were obtained in high yield. In contrast, in Comparative Example 1, which used only zirconium oxide as a catalyst, the reaction did not proceed even when heated at a higher reaction temperature of 250°C for 5 hours than in Examples 1-5. Furthermore, in Comparative Example 2, which used only sulfuric acid as a catalyst, some alcohol conversion occurred at 230°C, but no olefins were produced, and only by-products were obtained.

[0064] [Example 6] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 3 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.6 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C for 2.5 hours under a nitrogen atmosphere. Although the components cooled by the cooling unit 3 refluxed, the reaction solution could not be distilled. Therefore, 241 g of the liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0065] [Example 7] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 4.5 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.63 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230°C for 1 hour under a nitrogen atmosphere. The components cooled by the cooling unit 3 refluxed. Subsequently, the water supply to the cooling unit 3 was stopped, and the product was recovered by distillation by stirring at 230°C for 1.5 hours. The recovered product was treated with sodium sulfate to adsorb water from the recovered material. After the adsorption treatment, 127 g of a colorless, transparent liquid was obtained. In addition, 93 g of the liquid remaining in the flask was recovered. The recovered product and the residual liquid were measured by GC, and the component ratios and alcohol conversion rates relative to the total recovered material were calculated using the formula described above. The formation of a C12 monoolefin was confirmed by GC.

[0066] [Example 8] The reaction and evaluation were carried out in the same manner as in Example 7, except that the amount of zirconium oxide was changed to 5.24 g. 184 g of a colorless, transparent liquid was recovered by distillation, and 46 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 7. The formation of a C12 monoolefin was confirmed by GC.

[0067] [Example 9] The reaction and evaluation were carried out in the same manner as in Example 7, except that the amount of zirconium oxide was changed to 12 g. 115 g of a colorless, transparent liquid was recovered by distillation, and 115.5 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 7. The formation of a C12 monoolefin was confirmed by GC.

[0068] [Example 10] The reaction and evaluation were carried out in the same manner as in Example 7, except that the amount of zirconium oxide was changed to 15 g. 94 g of a colorless, transparent liquid was recovered by distillation, and 124 g of liquid remained in the flask. The component ratios and the alcohol conversion rate relative to the total recovered material were calculated in the same manner as in Example 7. The formation of a C12 monoolefin was confirmed by GC.

[0069] Table 2 summarizes the catalyst composition, reaction conditions, and analysis results of the recovered products in the reactions of Examples 6 to 10. [Table 2]

[0070] As shown in Table 2, in Examples 6-10, zirconium oxide and sulfuric acid were used as catalysts, and the reaction was carried out at a reaction temperature of 230°C for 2.5 hours to obtain olefins. In particular, in Examples 7 and 8, where the mass ratio of sulfuric acid to metal oxide was 10-15%, olefins were obtained in high yields.

[0071] [Example 11] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 3 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.3 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C for 2.5 hours under a nitrogen atmosphere. The components cooled by the cooling unit 3 refluxed. The reaction solution could not be distilled even after stopping the water supply to the cooling unit 3, so 276 g of the liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0072] [Example 12] The reaction and evaluation were carried out in the same manner as in Example 2, except that the amount of zirconium oxide was changed to 9 g and the amount of sulfuric acid to 0.9 g. 160 g of a colorless, transparent liquid was recovered by distillation, and 54.5 g of liquid remained in the flask. The product recovered by distillation and the residual liquid were measured by GC, and the component ratios to the total recovered material and the conversion rate of alcohol were calculated using the formula described above. The formation of a C12 monoolefin was confirmed by GC.

[0073] [Example 13] 498 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 10 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 1 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 1000 mL four-necked flask and stirred at 210 °C for 2.5 hours under a nitrogen atmosphere. The components cooled by the cooling unit 3 refluxed. The reaction solution could not be distilled even after stopping the water supply to the cooling unit 3, so 460 g of the liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0074] Table 3 summarizes the catalyst composition, reaction conditions, and analysis results of the recovered products in the reactions of Examples 11 to 13. [Table 3]

[0075] As shown in Table 3, in Examples 11 and 12, zirconium oxide and sulfuric acid were used as catalysts, and olefins were obtained at a reaction temperature of 230°C for a reaction time of 2.5 hours. In Example 13, zirconium oxide and sulfuric acid were used as catalysts, and olefins were obtained at a reaction temperature of 210°C for a reaction time of 2.5 hours.

[0076] [Example 14] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-dodecanol (Kao Corporation, Calcol® 2098), 6 g of γ-alumina (STREM CHEMICALS, INC.), and 0.6 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C for 2.5 hours under a nitrogen atmosphere. Since there was no reflux of the components cooled by the cooling unit 3 and distillation was not possible, 293 g of the brown, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered product were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0077] [Comparative Example 3] The reaction was carried out and evaluated under the same conditions as in Example 14, except that sulfuric acid was not added. As in Example 14, the reaction solution could not be refluxed or distilled, so 299 g of the cloudy white liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC.

[0078] [Example 15] The reaction was carried out and evaluated under the same conditions as in Example 14, except that γ-alumina was replaced with titanium dioxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). As with Example 14, the reaction solution could not be refluxed or distilled, so 291.5 g of the brown, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered product were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0079] [Comparative Example 4] The reaction was carried out and evaluated under the same conditions as in Example 15, except that sulfuric acid was not added. As with Example 14, the reaction solution could not be refluxed or distilled, so 300g of the gray, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC.

[0080] [Example 16] The reaction was carried out and evaluated under the same conditions as in Example 14, except that γ-alumina was replaced with silica-alumina (NeoBead SA, manufactured by Mizusawa Chemical Industries, Ltd.). As with Example 14, the reaction solution could not be refluxed or distilled, so 297 g of the brown, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered product were evaluated by GC. The formation of a C12 monoolefin was confirmed by GC.

[0081] [Comparative Example 5] The reaction was carried out and evaluated under the same conditions as in Example 16, except that sulfuric acid was not added. As in Example 16, the reaction solution could not be refluxed or distilled, so 295 g of the cloudy white liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC.

[0082] [Comparative Example 6] The reaction and evaluation were carried out in the same manner as in Example 14, except that γ-alumina was replaced with zirconium oxide (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100) and sulfuric acid was replaced with trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). Since the reaction solution could not be refluxed or distilled, 286 g of the brown, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered product were evaluated by GC.

[0083] [Comparative Example 7] 50 g of 1-dodecanol (manufactured by Kao Corporation, Calcol® 2098) and 1 g of solid acid catalyst 3% SO4-ZrO2 (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were added to a 200 mL three-necked flask and stirred at 250 °C for 5 hours under a nitrogen atmosphere. Water was supplied to the cooling unit 3, but there was no reflux and distillation was not possible. Therefore, 50 g of the gray, turbid liquid in the flask was recovered, and the component ratios and alcohol conversion rate in the recovered material were evaluated by GC.

[0084] Table 4 summarizes the catalyst composition, reaction conditions, and analysis results of the recovered products in Examples 14-16 and Comparative Examples 3-7. In Table 4, the notation "metal oxide (Al2O3, etc.) / sulfuric acid (10%)" in the catalyst column indicates that the mass ratio of sulfuric acid to the metal oxide is 10%. The notation "catalyst amount (%)" indicates the mass ratio of the catalyst (total of metal oxide and sulfuric acid) to the raw material alcohol. [Table 4]

[0085] As shown in Table 4, in Examples 14-16, alumina, titanium oxide, and silica-alumina were used as metal oxides, along with sulfuric acid, and olefins were obtained at a reaction temperature of 230°C for 2.5 hours. On the other hand, in Comparative Example 3, Comparative Example 4, and Comparative Example 5, which used only alumina as a catalyst, no alcohol conversion occurred at 230°C. In Comparative Example 6, which used zirconium oxide and trifluoromethanesulfonic acid, some alcohol conversion occurred, but no olefins were obtained. Furthermore, in Comparative Example 7, which used a solid acid catalyst of zirconium oxide supported with sulfuric acid, alcohol conversion occurred at a higher reaction temperature of 250°C for 5 hours than in the examples, but only a small amount of olefin was produced. This is thought to be because the sulfuric acid supported on zirconium oxide had lower catalytic activity than liquid sulfuric acid. From Comparative Example 6, it was found that sulfuric acid is a good acid to combine with metal oxides as a catalyst. From Comparative Example 7, it was found that using liquid sulfuric acid with metal oxides is more effective in producing olefins than using sulfuric acid supported on metal oxides.

[0086] [Example 17] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 1-octanol (Kao Corporation, Calcol® 0898), 6 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.6 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 200 °C for 1 hour under a nitrogen atmosphere. The components cooled in cooling section 3 refluxed. Subsequently, the water supply to cooling section 3 was stopped, and the product was recovered by distillation after stirring for 2 hours. 204 g of a colorless, transparent liquid was obtained by distillation. 1 The relative abundance of olefins and the conversion rate of alcohols were evaluated by 1H-NMR. Additionally, 9g of the brownish, turbid liquid remaining in the flask was collected. This residual liquid was analyzed by GC. 1 The component ratios and alcohol conversion rates relative to the total recovered material were calculated by combining the results of 1H-NMR measurements. The formation of a C8 monoolefin was confirmed by NMR. The olefins were identified by GC after reacting them with dimethyl disulfide. The resulting olefins were 10.8% 1-octene, 26.9% trans-2-octene, 18.8% cis-2-octene, 19.0% trans-3-octene, 16.2% cis-3-octene, 3.8% 4-octene, and 4.5% branch-octene.

[0087] [Example 18] The reaction was carried out using the apparatus outlined in Figure 1. 158 g of 2-octanol (manufactured by Ogura Synthetic Industries Co., Ltd.), 3.2 g of zirconium oxide (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.3 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 200 mL four-necked flask and stirred at 170°C for 2 hours under a nitrogen atmosphere. The components cooled in cooling unit 3 refluxed. Then, the water supply to cooling unit 3 was stopped, and the product was recovered by distillation by stirring at 170°C for 0.5 hours. The product recovered by distillation was treated with sodium sulfate to adsorb water from the recovered material. After the adsorption treatment, 110 g of a colorless, transparent liquid was obtained. In addition, 13 g of a brown, turbid liquid remaining in the flask was recovered. The product recovered by distillation and the residual liquid were each... 1 The components were measured by 1H-NMR, and the ratio of each component to the total recovered product and the conversion rate of alcohol were calculated by summing the measurement results. The formation of a C8 monoolefin was confirmed by NMR. The olefins were identified by GC after reacting the formed olefins with dimethyl disulfide. The resulting olefins were 1-octene (9.0%), trans-2-octene (25.1%), cis-2-octene (55.2%), trans-3-octene (4.6%), cis-3-octene (3.8%), 4-octene (0.8%), and branch-octene (1.5%).

[0088] [Example 19] The reaction was carried out using the apparatus outlined in Figure 1. 3040g of 1-dodecanol (Kao Corporation, Calcol® 2098), 61g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 6g of sulfuric acid (Fujifilm Wako Pure Chemical Industries Ltd., reagent grade) were added to a 5000mL four-necked flask and stirred at 230°C for 1.5 hours under a nitrogen atmosphere. The components cooled in cooling unit 3 refluxed. Then, the water supply to cooling unit 3 was stopped, and the product was recovered by distillation by stirring at 230°C for 2.5 hours. The product recovered by distillation was treated with sodium sulfate to adsorb water from the recovered material, yielding 2120g of a colorless, transparent liquid. In addition, 380g of the brown, turbid liquid remaining in the flask was recovered. The product recovered by distillation and the residual liquid were measured by GC, and the component ratios relative to the total recovered material and the alcohol conversion rate were calculated by summing the measurement results. The formation of a C12 monoolefin was confirmed by GC.

[0089] [Example 20] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of octadecanol (Kao Corporation, Calcol® 8098), 6 g of zirconium oxide (Daiichi Rare Elements Chemical Industry Co., Ltd., RC-100), and 0.6 g of sulfuric acid (Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C and 90 kPa for 1 hour. Then, the water supply to the cooling unit 3 was stopped, the pressure was further reduced to 1 kPa, and the mixture was stirred at 230 °C for 2.5 hours, and the product was recovered by distillation. The product recovered by distillation was treated with sodium sulfate to adsorb water from the recovered material, yielding 200 g of a colorless, transparent liquid. 39 g of the brown, turbid liquid remaining in the flask was recovered. The product and residue recovered by distillation were measured by GC, and the component ratios relative to the total recovered material and the alcohol conversion rate were calculated by summing the measurement results. The formation of a C18 monoolefin was confirmed by GC.

[0090] [Example 21] The reaction was carried out using the apparatus outlined in Figure 1. 300 g of 2-decyltetradecanol (manufactured by Shin-Nippon Rika Co., Ltd., N-JECOL® 240A), 6 g of zirconium oxide (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd., RC-100), and 0.6 g of sulfuric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., reagent grade) were added to a 500 mL four-necked flask and stirred at 230 °C for 1 hour under a nitrogen atmosphere. The mixture was then reduced to 1 kPa and stirred for 4.5 hours. Water was supplied to the cooling unit 3 during the reaction process, but the reaction solution could not be distilled. Therefore, the brown, turbid liquid in the flask was filtered, and 282 g of the brown liquid was recovered. The recovered material was measured by GC, and the component ratios and alcohol conversion rate were evaluated. GC confirmed the formation of a C24 monoolefin.

[0091] Table 5 summarizes the catalyst composition, reaction conditions, and analysis results of the recovered products in the reactions of Examples 17 to 21. In Table 5, the catalyst amount (%) indicates the mass ratio of the catalyst to the raw material alcohol (the total mass ratio of metal oxide and sulfuric acid). [Table 5]

[0092] As shown in Table 5, in Examples 17-21, primary or secondary alcohols having 8 to 24 carbon atoms were used as the starting alcohol. In Examples 17-21, zirconium oxide and sulfuric acid were used as catalysts, and the reaction was carried out at a temperature of 230°C or lower to obtain olefins in high yield.

[0093] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the present invention is defined by the claims and is intended to include all modifications in the sense and scope equivalent to the claims. [Explanation of symbols]

[0094] 1 Reaction vessel, 2 Cylinder section, 3, 4, 9 Cooling section, 5 Collection container, 6 Moisture adsorbent, 8 Branch pipe, 10 Stirrer, 11 Thermometer, 12 Side pipe, 13 Pump.

Claims

1. A method for producing olefins, comprising reacting an alcohol having 6 to 36 carbon atoms in a liquid phase at a temperature of 150°C or higher in the presence of a metal oxide and sulfuric acid not supported on a metal oxide.

2. The mass ratio of sulfuric acid to the metal oxide is 3% or more and 23% or less. A method for producing an olefin according to claim 1.

3. The alcohol has 8 to 24 carbon atoms and is a primary or secondary alcohol, either linear or branched. A method for producing an olefin according to claim 1 or claim 2.

4. The method for producing an olefin according to claim 1 or 2, wherein the metal oxide is one or more selected from the group consisting of oxides of elements selected from groups 3 to 6 and 12 to 13 of the periodic table.

5. The aforementioned metal oxide is one or more selected from the group consisting of zirconium oxide, titanium oxide, aluminum oxide, silica alumina, tungsten oxide, scandium oxide, yttrium oxide, hafnium oxide, vanadium oxide, and niobium oxide. A method for producing an olefin according to claim 1 or claim 2.

6. The mass ratio of the total amount of the metal oxide and sulfuric acid to the alcohol is 0.5% or more. A method for producing an olefin according to claim 1 or claim 2.

7. A reaction vessel capable of stirring alcohol, a metal oxide, and sulfuric acid not supported on a metal oxide while heating, It comprises a collection unit that cools and collects the generated olefin, A moisture adsorption section containing a moisture adsorbent is provided between the reaction tank and the collection section. A reaction apparatus for a method of producing an olefin according to claim 1 or claim 2.

8. A method for producing an olefin, comprising obtaining an olefin from an alcohol using the reaction apparatus described in claim 7.

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