Catalyst for preparation of linear alpha olefin, method for preparing same and method for preparing linear alpha olefin using same

Abstract

The present invention relates to: a catalyst enabling enhanced conversion rate and selectivity when preparing a linear alpha olefin through a dehydration reaction of a primary alcohol; a method for preparing same; and a method for preparing a linear alpha olefin using same. The present invention may provide a catalyst having optimized acid and basic sites through an interaction between cerium oxide and aluminum oxide, and may improve the selectivity and conversion rate to a linear alpha olefin by applying the catalyst to a dehydration reaction of a primary alcohol. In addition, the present invention may enhance the yield of the linear alpha olefin by controlling conditions such as the cerium loading of the catalyst, the reaction temperature, etc., and may also exhibit a selectivity-enhancing effect for a biomass-derived alcohol having five or more carbon atoms, thereby enabling the linear alpha olefin to be prepared in an eco-friendly and economical manner.

Description

Catalyst for producing linear alpha olefins, method for producing the same, and method for producing linear alpha olefins using the same

[0001] The present invention relates to a catalyst for producing linear alpha olefins, a method for producing the same, and a method for producing linear alpha olefins using the same, and more particularly, to a catalyst capable of improving conversion rate and selectivity in producing linear alpha olefins through a dehydration reaction of a primary alcohol, a method for producing the same, and a method for producing linear alpha olefins using the same.

[0002] Linear alpha-olefins (LAOs) are a general term for linear hydrocarbons with one double bond in the alpha position of their molecular structure, and are used as intermediates in the synthesis of various products such as (co)monomers of polymers, lubricants, plasticizers, and surfactants.

[0003] Known technologies for synthesizing linear alpha olefins include ethylene oligomerization, naphtha catalytic cracking, and paraffin dehydrogenation. For example, Korean Patent Publication No. 10-2012-0050963 relates to a method for producing linear alpha olefins by ethylene oligomerization, and describes a technology for injecting and reacting additives after oligomerization using ethylene and a catalyst. However, this technology has the disadvantage of requiring an additional separation process due to low selectivity for linear alpha olefins, and being environmentally unfriendly as most of the technology uses petroleum-based materials.

[0004] Accordingly, linear alpha olefin production technology utilizing alcohol dehydration is attracting attention as an alternative technology. Utilizing alcohol dehydration has the advantage of being environmentally friendly in the production of linear alpha olefins. For example, Korean Patent Publication No. 10-2306324 relates to a technology for producing alpha olefins using the dehydration of primary alcohols. The technology describes a technology for dehydrating primary alcohols using a catalyst comprising a composite metal oxide of magnesium aluminate and hydrotalcite as a carrier and a Group 6 transition metal particle supported thereon.

[0005] However, the above technology has the disadvantage of limiting the selectivity of linear alpha olefins when applied to alcohols with 5 or more carbon atoms, such as 1-octanol. Furthermore, research utilizing dehydration reactions of other alcohols has primarily focused on alcohols with smaller carbon atoms, and research on biomass-derived alcohols with 5 or more carbon atoms is not actively underway.

[0006] Therefore, there is a need for the development of a technology that can obtain linear alpha olefins in high yields in an environmentally friendly manner by improving the dehydration conversion rate and selectivity of linear alpha olefins using primary alcohols, and that can also exhibit the same effect of improving the selectivity and yield of linear alpha olefins when applied to alcohols having 5 or more carbon atoms.

[0007] The purpose of the present invention is to provide a catalyst that can be applied to the dehydration reaction of primary alcohol to improve the selectivity of linear alpha olefin.

[0008] Another object of the present invention is to provide a method for producing the catalyst.

[0009] Another object of the present invention is to provide a method for producing a high yield of linear alpha olefin using the above catalyst.

[0010] To achieve the above purpose, the present invention provides a catalyst for producing linear alpha olefins, in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3).

[0011] In the catalyst of the present invention, the amount of cerium supported may be 3 to 30 wt% with respect to the total weight of the catalyst.

[0012] In the present invention, the acid point of the catalyst may be 0.80 to 1.20 mmol / g.

[0013] In the catalyst of the present invention, the acid sites of the strong acid may be 30 to 40% of the total acid sites.

[0014] In the present invention, the base point of the catalyst may be 0.80 to 1.20 mmol / g.

[0015] In the catalyst of the present invention, the base point of the strong base may be 35 to 40% of the total base points.

[0016]

[0017] The present invention can also provide a method for producing a catalyst for producing the linear alpha olefin.

[0018] The method for producing a catalyst for producing linear alpha olefins of the present invention may include the steps of: preparing a mixed solution containing cerium salt and aluminum oxide; and drying and calcining the mixed solution to produce a catalyst in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3).

[0019] In the present invention, the cerium salt may be at least one selected from the group consisting of cerium nitrate, cerium ammonium nitrate, cerium ammonium sulfate, cerium acetate, cerium sulfate, cerium carbonate, cerium hydroxide, cerium chloride, cerium bromide, cerium fluoride, and cerium iodide.

[0020] In the present invention, the solvent of the mixed solution may be at least one selected from the group consisting of water (distilled water), acetone, alcohol, ethyl acetate, hexane, heptane, toluene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dimethyl oxalate, and methylpyrrolidone.

[0021] In the present invention, the calcination can be performed by increasing the temperature at a rate of 2 to 8°C / min under conditions of 350 to 600°C.

[0022]

[0023] The present invention can also provide a method for producing linear alpha olefin using the catalyst.

[0024] The above linear alpha olefin can be produced by dehydrating a primary alcohol in the presence of a catalyst in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3).

[0025] In the present invention, the primary alcohol may be at least one linear primary alcohol selected from the group consisting of 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol.

[0026] In the present invention, the dehydration reaction can be performed at a temperature higher than 200°C and lower than 400°C.

[0027] In the present invention, the method for producing the linear alpha olefin may include a step of loading and activating the catalyst into a reactor; and a step of injecting a primary alcohol into the reactor to cause a dehydration reaction, thereby obtaining the linear alpha olefin.

[0028] In the present invention, activation of the catalyst can be performed at 300 to 700°C.

[0029] According to the present invention, a catalyst having optimized acid and base sites can be provided through the interaction of cerium oxide and aluminum oxide, and by applying this to the dehydration reaction of a primary alcohol, the selectivity and conversion rate to linear alpha olefin can be improved. Furthermore, in the present invention, the yield of linear alpha olefin can be improved by controlling conditions such as the amount of cerium supported on the catalyst and the reaction temperature, and the selectivity is also improved for alcohols having 5 or more carbon atoms, so that linear alpha olefin can be produced in an environmentally friendly and economical manner.

[0030] Figure 1 is a graph showing the conversion rate of 1-hexanol dehydration reaction and the yield of 1-hexene according to the amount of cerium supported on the catalyst in one embodiment of the present invention.

[0031] Figure 2 shows the results of measuring the acid point of a CeO2 / Al2O3 catalyst using ammonia thermal desorption (NH3-TPD) according to one embodiment of the present invention.

[0032] FIG. 3 shows the results of measuring the base point of a CeO2 / Al2O3 catalyst using carbon dioxide thermal desorption (CO2-TPD) according to one embodiment of the present invention.

[0033] Hereinafter, specific implementations of the present invention will be described in more detail. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0034]

[0035] Linear alpha olefins (LAOs) are linear hydrocarbons with a single double bond in the alpha position of their molecular structure. Linear alpha olefins are primarily produced through paraffin dehydrogenation, ethylene oligomerization, and the Fischer-Tropsch process, all of which rely on petrochemicals. Consequently, the manufacturing technology for linear alpha olefins has generally been plagued by environmental concerns, such as oil depletion and accelerated global warming, as well as economic issues stemming from raw material supply and demand fluctuations due to oil price fluctuations and cost fluctuations.

[0036] The present invention is capable of solving such problems, and relates to a catalyst capable of producing linear alpha olefins in an environmentally friendly and economical manner by utilizing the dehydration reaction of primary alcohol.

[0037] The dehydration reaction of primary alcohol proceeds at the acid site of the catalyst, and for example, the production of alpha olefins through the dehydration reaction of 1-hexanol proceeds according to the reaction formula below.

[0038] [Reaction Formula 1]

[0039]

[0040] However, since the activation energy for the etherification reaction is thermodynamically lower than that for producing alpha olefins through the dehydration reaction of alcohol, dihexyl ether is produced at low temperatures as shown in the reaction equation below.

[0041] [Reaction Formula 2]

[0042]

[0043] Thus, at low temperatures during the primary alcohol dehydration reaction, dialkyl ethers are produced through etherification, a side reaction of alcohol. Therefore, high temperatures are necessary to selectively produce linear alpha olefins. However, high temperatures pose a problem in that alpha olefins undergo isomerization through the use of a strongly acidic catalyst, producing a variety of isomers.

[0044] In the present invention, by using a catalyst in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3), the selectivity and yield of linear alpha olefin can be improved.

[0045] In the present invention, the aluminum oxide used in the catalyst may be γ-aluminum oxide, i.e., aluminum oxide having a porous structure formed by dehydrating boehmite at high temperature.

[0046] The catalyst according to the present invention has acid and base sites strengthened by the interaction between cerium and aluminum oxide, and when using it to dehydrate alcohol, it has an excellent conversion rate and high selectivity for linear alpha olefins, and can also exhibit excellent performance when applied to alcohols having 5 or more carbon atoms.

[0047] In this regard, in an embodiment of the present invention, a dehydration reaction of 1-hexanol was performed using a KCC-1LHPW catalyst, an aluminum oxide catalyst, an aluminum oxide catalyst loaded with niobium oxide, a cerium oxide catalyst, and an aluminum oxide catalyst loaded with cerium oxide, respectively, and as a result, it was confirmed that the aluminum oxide catalyst loaded with cerium oxide had a much superior 1-hexene selectivity compared to other catalysts.

[0048] In addition, in the present invention, the selectivity and conversion rate of linear alpha olefin can be further improved by optimizing the acid and base sites of the catalyst by controlling the amount of cerium supported.

[0049] In the present invention, the amount of cerium supported in the catalyst may be 3 to 30 wt%, preferably 5 to 25 wt%, specifically 5 to 15 wt%, and more preferably 8 to 12 wt%, based on the total weight of the catalyst.

[0050] If the cerium loading amount is too small, the interaction between cerium oxide and aluminum oxide will not be sufficient, and if the cerium loading amount is too large, the saturated cerium oxide may aggregate, resulting in a problem of poor dispersion.

[0051] In this regard, in an embodiment of the present invention, a catalyst was manufactured by adjusting the loading amount of cerium to 5, 10, 15, and 25 wt%, and a dehydration reaction of 1-hexanol was performed using the catalyst. As a result, when the loading amount of cerium was 10 wt%, the conversion rate was as high as 99.2%, and the selectivity for 1-hexene was excellent at 88.8%, so that the yield of 1-hexene was as high as 88.1%. As such, in the present invention, by adjusting the loading amount of cerium, the conversion rate of primary alcohol and the selectivity for linear alpha olefin can be improved, thereby increasing the yield of linear alpha olefin.

[0052] In the present invention, linear alpha olefins can be obtained in high yield when applied to a primary alcohol dehydration reaction due to the change in the strength of acid sites and the basicity of cerium oxide through the interaction between cerium oxide and aluminum oxide.

[0053] The dehydration reaction of primary alcohol proceeds at the acid site of the catalyst, and since a catalyst with too strong an acidity causes the production of isomers through a double bond shift, it is important to control the acid site of the catalyst for the selective production of alpha olefins.

[0054] In the present invention, the acid point of the catalyst may be 0.80 to 1.20 mmol / g, preferably 1.05 to 1.15 mmol / g. In particular, the catalyst of the present invention is characterized in that the acid point of aluminum oxide is strengthened to a strong acid by cerium oxide, so that the acid point of the strong acid may be 30% or more, specifically 30 to 40%, and preferably 35 to 40% of the total acid points.

[0055] In addition, the base point of the catalyst may be 0.70 to 1.00 mmol / g, preferably 0.95 to 0.99 mmol / g. In the present invention, the base point is strengthened into a strong base by the interaction between cerium oxide and aluminum oxide, so that the base point of the strong base may be 35% or more, specifically 35 to 40%, preferably 37 to 40% of the total base points.

[0056] In this way, in the present invention, by applying a catalyst with optimized acid and base sites to the dehydration reaction of primary alcohol, the selectivity and conversion rate to linear alpha olefin can be greatly improved.

[0057]

[0058] The present invention can also provide a method for producing a catalyst in which cerium oxide is supported on aluminum oxide.

[0059] The catalyst of the present invention can be manufactured through an impregnation method, and specifically, can be manufactured through a step of manufacturing a mixed solution containing cerium salt and aluminum oxide; and a step of drying and calcining the mixed solution to form a catalyst in which cerium oxide is supported on aluminum oxide.

[0060] The above cerium salt may be a precursor of cerium oxide, and may be at least one selected from the group consisting of cerium nitrate, cerium ammonium nitrate, cerium ammonium sulfate, cerium acetate, cerium sulfate, cerium carbonate, cerium hydroxide, cerium chloride, cerium bromide, cerium fluoride, and cerium iodide. The above cerium salt may be used in the form of a hydrate.

[0061] The above cerium salt and aluminum oxide are mixed in a solution phase. At this time, the solvent of the solution may be at least one selected from the group consisting of water (distilled water), acetone, alcohol, ethyl acetate, hexane, heptane, toluene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dimethyl oxalate, and methylpyrrolidone, and preferably distilled water.

[0062] In the above mixed solution, the concentration of aluminum oxide may be 0.1 to 3 g / mL, preferably 0.5 to 2 g / mL, and the concentration of cerium salt may be appropriately adjusted depending on the cerium loading amount of the catalyst to be manufactured.

[0063] To prepare the above mixed solution, the mixed solution can be prepared by diluting the cerium salt in a solvent, adding aluminum oxide, and then mixing.

[0064] Once the above mixed solution is prepared, a step of drying it to obtain a solid sample is performed.

[0065] The above drying can be performed using known techniques and devices such as an oven, hot air, constant temperature and humidity, and microwave, and can be performed at a temperature of 40 to 100°C, preferably 50 to 80°C, to completely remove the solvent.

[0066] After evaporating all the solvent through the above drying process, a catalyst is manufactured through a step of calcining the solid sample at high temperature.

[0067] The above calcination can be performed while increasing the temperature under conditions of 350 to 600°C, preferably 400 to 500°C. At this time, the temperature increasing rate can be 2 to 8°C / min, preferably 4 to 6°C / min, and the total calcination time can be 2 to 6 hours, preferably 3 to 5 hours.

[0068] By the above calcination process, a powder-type catalyst in which cerium oxide is supported on aluminum oxide can be obtained.

[0069] In the catalyst manufactured in this manner, cerium oxide combines with the strong Lewis acid site of aluminum oxide to lower the acid site of the catalyst, and increases the base site of the catalyst through the Lewis acid site and basicity of cerium oxide itself, thereby selectively producing linear alpha olefins in the first alcohol dehydration reaction.

[0070]

[0071] The present invention can also provide a method for producing linear alpha olefin using the catalyst.

[0072] According to the present invention, a linear alpha olefin can be produced by dehydrating a primary alcohol in the presence of the catalyst. Specifically, the linear alpha olefin production method can be performed by the steps of loading and activating a catalyst into a reactor; and the step of injecting a primary alcohol into the reactor to cause a dehydration reaction.

[0073] The activation of the above catalyst can be performed at 300 to 700°C, preferably 400 to 600°C, and the catalyst is activated by maintaining the temperature for 1 to 4 hours, and then the primary alcohol is injected to initiate the reaction.

[0074] The primary alcohol used in the above reaction may be at least one linear primary alcohol selected from the group consisting of alcohols having 3 to 10 carbon atoms, i.e., 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol, and the linear alpha olefin produced therefrom may be at least one selected from the group consisting of linear alpha olefins having 3 to 10 carbon atoms, 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. In particular, the present invention is preferable because it is possible to perform a reaction with high selectivity and conversion rate to linear alpha olefin even when applied to alcohols having 5 or more carbon atoms.

[0075] In the above reaction, when the primary alcohol is injected, the reaction can be carried out by injecting it under conditions of a nitrogen flow of 10 to 1,000 mL / min, for example, 50 to 200 mL / min, and then stabilizing the flow.

[0076] In the present invention, the temperature of the dehydration reaction can be controlled to a temperature higher than 200°C and lower than 400°C, and preferably, it can be controlled to a temperature higher than 250°C and lower than 400°C. If the temperature is low, the etherification reaction of the primary alcohol proceeds, mainly producing ethers, so the selectivity of linear alpha olefins is low. On the other hand, if the temperature is too high, the isomerization of alpha olefins is promoted, which may cause problems such as reduced selectivity and purity. In this respect, the temperature of the dehydration reaction may be more preferably 280 to 380°C.

[0077] In this regard, in an embodiment of the present invention, dehydration reactions were performed at 150, 200, 250, 300, 350 and 400°C for 1-pentanol, 1-hexanol and 1-octanol, respectively. As a result, it was confirmed that in the case of 1-pentanol, the conversion rate and selectivity were excellent at 300°C and 350°C, and in particular, the yield of 1-pentene was the highest at 300°C. In addition, in the case of 1-hexanol, the conversion rate was high at 90% or higher under the conditions of 300℃, 350℃, and 400℃, and the selectivity of 1-hexene was the best at 88.8% at 350℃, resulting in a high yield of 88.1%. In the case of 1-octanol, the conversion rate was high at 90% or higher at 250, 300, 350, and 400℃, and the selectivity of 1-octene was the highest at 64.4% at 300℃.

[0078] Accordingly, the temperature range of the first alcohol dehydration reaction using the catalyst of the present invention is preferably 280 to 380°C, and the specific optimal temperature varies depending on the carbon number of the alcohol, and it was confirmed that 280 to 320°C is the most preferable for 1-pentanol and 1-octanol, and 330 to 380°C is the most preferable for 1-hexanol.

[0079] Thus, in the present invention, by reacting a primary alcohol in the presence of the catalyst and optimizing the reaction temperature, linear alpha olefins can be produced in high yield. Furthermore, the catalyst of the present invention exhibits the above-described effect in the dehydration reaction of a primary alcohol having 5 or more carbon atoms, thereby enabling the effective production of linear alpha olefins using biomass-derived 1-pentanol, 1-hexanol, 1-octanol, and the like. Therefore, the present invention can be effectively utilized in the development of technologies for producing high value-added compounds derived from biomass.

[0080]

[0081] Example

[0082]

[0083] The present invention is described in more detail through the following examples. However, these examples are intended to illustrate some experimental methods and configurations of the present invention, and the scope of the present invention is not limited to these examples.

[0084]

[0085] Manufacturing example: Manufacturing of a catalyst in which cerium oxide is supported on aluminum oxide.

[0086]

[0087] A CeO2 / Al2O3 catalyst was prepared by an impregnation method using a cerium oxide precursor and aluminum oxide.

[0088] A mixture was made by diluting cerium nitrate hexahydrate (Ce(NO3)3·6H2O), a precursor of cerium oxide, in 10 mL of distilled water, and 1 g of gamma-aluminum oxide (γ-Al2O3) was added to the well-diluted mixture, which was then stirred and mixed for 6 hours. The mixture was placed in an oven at 80°C to evaporate all the distilled water, and the resulting solid sample was placed in an electric furnace and calcined at 450°C at a heating rate of 5°C / min for 4 hours.

[0089] Using the above method, catalysts having Ce loadings of 5, 10, 15, and 25 wt% based on the total catalyst weight were manufactured, and each catalyst was expressed as nCeO2 / Al2O3 (n=mass percent content of Ce). For example, in the case of a 10% Ce catalyst, 0.310 g of cerium nitrate hexahydrate was used based on the calculation of the molecular weight of cerium nitrate hexahydrate (434.22 g) and the atomic weight of cerium (140.116 g), and the weight of cerium nitrate hexahydrate used was adjusted according to the Ce loading amount.

[0090]

[0091] Experimental Example 1: Analysis of 1-Hexanol Dehydration Reaction Performance According to Catalyst Type

[0092]

[0093] The dehydration reaction of 1-hexanol was performed using the 10CeO2 / Al2O3 catalyst manufactured according to the method of the above manufacturing example, and the conversion rate and selectivity were measured.

[0094] The dehydration reaction was carried out in a quartz tube (outer diameter 6 mm, inner diameter 4 mm, length 330 mm) of a continuous catalytic reactor, and the temperature was controlled using a vertical tube electric furnace. A gas flow path was created through 1 / 4-inch stainless steel gas lines at the top and bottom of the reactor, and an auxiliary passage was created so that the gas could flow into the reactor or the auxiliary passage by operating a valve. A heating tape was tightly wrapped around the gas line, and heat was applied through a slideax to control the gas temperature. A thermocouple was installed in the gas line to check the gas temperature and maintain it at 200℃.

[0095] 50 mg of catalyst was fixed inside the quartz tube using quartz wool, and before the reaction, the temperature of the reactor was increased to 500°C for 1 hour under a nitrogen flow of 30 mL, and then the temperature was maintained for 2 hours to activate the catalyst. After the catalyst activation, the temperature of the reactor was adjusted to 350°C. Simultaneously, the gas flow was switched to the auxiliary passage, and 0.3 mL / h of 1-hexanol was injected using a syringe pump under a nitrogen flow of 100 mL / min, and the flow of 1-hexanol was stabilized for 30 minutes. The gas flow was switched from the auxiliary passage to the reactor to obtain a mass space velocity (WHSV) of 5 h. -1 The reaction was carried out under the conditions, and the start of the reaction was recorded immediately after the gas flow was switched from the auxiliary passage to the reactor.

[0096] The reaction product analysis was performed using an online-connected GC-FID (Chrozen GC, YoungIn Chromass) equipment, and the reactant alcohol was analyzed using a DB-WAX (Agilent J&W, 0.250 mm x 0.25 μm x 30 m) column, and the product olefin was analyzed using a GS-Gaspro (Agilent J&W, 0.32 mm x 60 m) column. Qualitative / quantitative analysis was performed, and the conversion (X), selectivity (S), and yield (Y) were calculated using the following equations, and the results are shown in Table 1 below. For comparison, KCC-1LHPW, Nb2O5 / Al2O 3, The same experiment was performed for Al2O3 and CeO2 catalysts, and the results are shown in Table 1 below. The KCC-1LHPW catalyst was made by using KCC-1 (fibrous nano-silica) as a support and HPW (phosphtungstic acid, H3PW). 12 It refers to a catalyst containing O4 (DOI: 10.1007 / s11814-021-0768-6).

[0097] Conversion rate (X) = [Alcohol reacted (mmol / min) / Alcohol injected (mmol / min)] × 100 (%)

[0098] Selectivity (S) = [Product (mmol / min) / Total Product (mmol / min)] × 100 (%)

[0099] Yield (Y) = X × S / 100 (%)

[0100]

[0101] Catalytic conversion (%) Selectivity (%) 1-hexene Yield (%) 1-hexene c-2-hexene t-2-hexene c-3-hexene t-3-hexene KCC-1LHPW 8 3.13 5.12 3.7 19.8 3.6 17.8 29.2 Nb 2 O 5 / Al 2 O 3 9 0.94 0.92 1.7 18.03 216.2 37.2 Al 2 O 3 10 0.7 24.3 32.76 0 29.37.8 CeO 2 / Al 2 O 3 9 9.2 8 8.8 4.6 3.01 02.7 8 8.1 CeO 2 6 4.34 1.26 8 22.78 8 20.4 26.5

[0102]

[0103] Dehydration of 1-hexanol using various acid-specific catalysts showed that catalysts with many acid sites exhibited high conversion rates, but only had a selectivity for 1-hexene of around 40%. Furthermore, cerium oxide, which has few acid sites and many basic sites, exhibited very low conversion rates, but showed a somewhat higher selectivity for 1-hexene than other catalysts.

[0104] In the case of the aluminum oxide catalyst, a 100% conversion was observed, but due to the high acidity and low basicity of the catalyst, the isomerization of 1-hexene was activated, and the selectivity for 1-hexene was greatly reduced. However, the catalyst supporting cerium oxide on aluminum oxide showed a very high 1-hexanol conversion of 99.2%, and furthermore, the selectivity for 1-hexene was excellent at 88.8%, and as a result, 1-hexene could be produced in a high yield of 88.1%.

[0105]

[0106] Experimental Example 2: Analysis of 1-hexanol dehydration performance according to cerium loading amount

[0107]

[0108] To investigate the effect of cerium oxide on CeO2 / Al2O3 catalysts, catalysts were prepared by adjusting the cerium loading to 5, 10, 15, and 25 wt%, respectively. Dehydration of 1-hexanol was performed using each catalyst, and the results of calculations for the conversion rate, olefin selectivity, and 1-hexene yield are shown in Fig. 1 and Table 2 below.

[0109]

[0110] Catalytic conversion (%) Selectivity (%) 1-hexene yield (%)1-hexenec-2-hexenet-2-hexenec-3-hexenet-3-hexene5CeO2 / Al2O387.972.616.45.31.14.763.810CeO2 / Al2O399.288.84.63.01.02.788.115CeO2 / Al2O391.474.715.94.51.04.068.325CeO2 / Al2O310064.221.46.81.46.164.2Al2O31007.824.332.76.029.37.8CeO264.341.26.822.78.820.426.5

[0111]

[0112] According to the above experimental results, when the loading amount of cerium was 5 wt% with respect to the total weight of the catalyst, the conversion rate and the selectivity for 1-hexene were somewhat low, and when the loading amount increased to 25 wt%, the conversion rate increased to 100%, but the selectivity for 1-hexene decreased to less than 65%. However, when the loading amount of cerium was 10 wt%, the conversion rate was high at 99.2%, and the selectivity for 1-hexene was also greatly improved, confirming that the yield of 1-hexene was high at 88.1%.

[0113] Accordingly, it was confirmed that the performance of the catalyst was the best when the cerium loading amount in the CeO2 / Al2O3 catalyst was 10 wt%.

[0114]

[0115] Experimental Example 3: Analysis of acid and base sites of catalysts according to the weight ratio of cerium oxide.

[0116]

[0117] In order to analyze the cause of the improvement in the performance of alcohol dehydration by a catalyst supporting cerium oxide, ammonia temperature-induced desorption (NH3-TPD) and carbon dioxide temperature-induced desorption (CO2-TPD) analyses were performed on Al2O3 catalysts, CeO2 catalysts, and CeO2 / Al2O3 catalysts having weight ratios of 5, 10, 15, and 25% of cerium oxide, respectively, and the results are shown in Figs. 2 and 3 and Table 3 below.

[0118]

[0119] Catalytic acid point (mmolg -1 ) base point (mmolg -1 ) Weak acid Intermediate acid Strong acid Total Weak base Intermediate base Strong base Total Al2O3 0.09 10.69 30.30 21.08 50.05 60.54 20.32 50.92 4 CeO2 0.05 80.08 10.00 90.13 90.28 50.35 60.31 20.95 35 Ca 0.09 10.64 40.44 51.18 0.06 9 0.50 10.3790.94910CA0.0810.6050.4171.1030.0660.5300.3640.96015CA0.0840.5200. 3610.9650.0540.4180.3060.77825CA0.0850.4590.3590.9010.0610.4020.3450.808

[0120]

[0121] As a result, it was confirmed that pure aluminum oxide had more acid sites and fewer base sites than cerium oxide, and in the case of aluminum oxide loaded with cerium oxide, the acid sites were somewhat strengthened from moderately acidic to strongly acidic, and the base sites were somewhat strengthened from moderately base to strongly base. Accordingly, it was confirmed that the acid and base sites were strengthened due to the interaction between cerium and aluminum oxide.

[0122] Meanwhile, the catalyst containing 15 wt% or more of cerium showed a decrease in the total acid and base points due to the agglomeration of saturated cerium oxide and a decrease in dispersion.

[0123] According to the above experimental results, it was confirmed that the acid and base points of the catalyst were optimal when the cerium loading amount in the CeO2 / Al2O3 catalyst was 10 wt%.

[0124]

[0125] Experimental Example 4: Analysis of Conversion Rate and Selectivity According to Alcohol Type and Temperature

[0126]

[0127] The catalyst was applied to other primary alcohols, 1-pentanol and 1-octanol, and its performance was confirmed.

[0128] The reaction was carried out in the same manner as in Experimental Example 1, but the heating temperature using Slidex before catalyst activation was maintained at 170°C for the reaction of 1-pentanol and at 220°C for the reaction of 1-octanol.

[0129] To determine the effect of reaction temperature, dehydration reactions of 1-pentanol, 1-hexanol, and 1-octanol were performed at 50°C intervals in the temperature range of 150 to 400°C, and the results are shown in Tables 4 to 6 below.

[0130]

[0131] Temperature (℃) Conversion (%) 1-Pentene Selectivity (%) 1-Pentene Purity (%) DPE Selectivity (%) 1-Pentene Yield (%) 150 53.11.5 17.59 1.60.8 200 61.73.4 36.49 0.52.12 50 85.14 1.78 3.55 0.135.5 300 100 94.79 4.70 94.73 50 100 89.289.20 89.24 00 100 72.0 72.0

[0132]

[0133] Temperature (℃) Conversion (%) 1-Hexene Selectivity (%) 1-Hexene Purity (%) DHE Selectivity (%) 1-Hexene Yield (%) 150 69.500 1000 200 61.84.286.995.22.6250 87.245.265.230.739.4300 94.043.843.8041.2350 99.288.888.8088.1400 92.132.432.4029.8

[0134]

[0135] Temperature (℃) Conversion (%) 1-Octene Selectivity (%) 1-Octene Purity (%) DOE Selectivity (%) 1-Octene Yield (%) 1508.700 1000 200 57.7 34.8 > 996 4.9 20.12 50 94.25 0.27 4.9 3.0 47.33 00 99.8 64.4 75.114.26 4.33 50 98.24 0.6 40.6 0 39.9 400 98.7 60.5 77.6 22.15 9.7

[0136]

[0137] As a result, at low temperatures of 150 to 200°C, 1-pentanol mainly produced dipentyl ether (DPE), 1-hexanol mainly produced dihexyl ether (DHE), and 1-octanol mainly produced dioctyl ether (DOE). As the temperature increased, the selectivity of olefins tended to increase. Accordingly, it was confirmed that the temperature should be controlled higher than 200°C, and 250°C or higher is preferable.

[0138] However, if the temperature is raised too much, the isomerization of linear alpha olefins is promoted or etherification progresses, which tends to lower selectivity and purity. Therefore, it was confirmed that the temperature should be controlled to 400°C or lower, and it is preferable to control it to lower than 400°C.

[0139] In the case of 1-pentanol, the olefin production performance was excellent with a conversion rate of 100% and a selectivity of 94.7% at 300°C, and 1-hexanol showed the highest yield with a conversion rate of 99.2% and a selectivity of 88.8% at 350°C. In addition, 1-octanol showed the best yield with a conversion rate of 99.8% and a selectivity of 64.4% at 300°C.

[0140] According to the above results, it was found that optimization of the reaction temperature is a very important factor in producing linear alpha olefins with high selectivity, and that the yield can be further improved by optimally controlling the temperature according to the carbon number of the alcohol.

[0141]

[0142] While specific aspects of the present invention have been described in detail above, it will be apparent to those skilled in the art that these specific descriptions merely represent preferred embodiments and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A catalyst for producing linear alpha olefins, comprising cerium oxide (CeO2) supported on aluminum oxide (Al2O3).

2. In paragraph 1, A catalyst for producing linear alpha olefins, wherein the amount of cerium supported is 3 to 30 wt% based on the total weight of the catalyst.

3. In paragraph 1, A catalyst for producing linear alpha olefins, wherein the acid point of the catalyst is 0.80 to 1.20 mmol / g.

4. In paragraph 3, A catalyst for producing linear alpha olefins, wherein the acid sites of the strong acid in the above catalyst are 30 to 40% of the total acid sites.

5. In paragraph 1, A catalyst for producing linear alpha olefins, wherein the base point of the catalyst is 0.80 to 1.20 mmol / g.

6. In paragraph 5, A catalyst for producing linear alpha olefins, wherein the base point of the strong base is 35 to 40% of the total base points in the above catalyst.

7. A step of preparing a mixed solution containing cerium salt and aluminum oxide; and A step of manufacturing a catalyst in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3) by drying and calcining the above mixed solution. A method for producing a catalyst for producing linear alpha olefins, comprising:

8. In paragraph 7, A method for producing a catalyst for producing linear alpha olefins, wherein the cerium salt is at least one selected from the group consisting of cerium nitrate, cerium ammonium nitrate, cerium ammonium sulfate, cerium acetate, cerium sulfate, cerium carbonate, cerium hydroxide, cerium chloride, cerium bromide, cerium fluoride, and cerium iodide.

9. In paragraph 7, A method for producing a catalyst for producing linear alpha olefin, wherein the solvent of the above mixed solution is at least one selected from the group consisting of water (distilled water), acetone, alcohol, ethyl acetate, hexane, heptane, toluene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dimethyl oxalate, and methylpyrrolidone.

10. In paragraph 7, A method for producing a catalyst for producing linear alpha olefins, wherein the calcination is performed by raising the temperature at a rate of 2 to 8°C / min under conditions of 350 to 600°C.

11. A method for producing linear alpha olefin, wherein a linear alpha olefin is obtained by dehydrating a primary alcohol in the presence of a catalyst in which cerium oxide (CeO2) is supported on aluminum oxide (Al2O3).

12. In paragraph 11, A method for producing a linear alpha olefin, wherein the primary alcohol is at least one linear primary alcohol selected from the group consisting of 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol.

13. In paragraph 11, A method for producing linear alpha olefin, wherein the above dehydration reaction is performed at a temperature higher than 200°C and lower than 400°C.

14. In paragraph 11, The above manufacturing method comprises the steps of loading and activating the catalyst into a reactor; and A method for producing linear alpha olefin, comprising a step of obtaining linear alpha olefin by injecting primary alcohol into the above reactor and performing a dehydration reaction.

15. In paragraph 14, A method for producing linear alpha olefin, wherein activation of the above catalyst is performed at 300 to 700°C.

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