KR20210157285A - Dehydration catalyst, method for preparing the same, and method for preparing alkene using the same - Google Patents

Abstract

The present invention relates to a dehydration catalyst, a method for preparing the same, and a method for preparing an alkene using the same. More specifically, the present invention relates to a dehydration catalyst that is mixed-phase alumina, a method for preparing the dehydration catalyst, and a method for preparing an alkene using the dehydration catalyst, wherein the mixed-phase alumina comprises 1-18 wt% of alpha-alumina, 65-95 wt% of theta-alumina, and 4-34 wt% of delta-alumina.

Description

Dehydration catalyst, method for preparing same, and method for preparing alkene using same

The present invention relates to a dehydration catalyst, a method for preparing the same, and a method for preparing an alkene using the same, and more particularly, to improve the alcohol conversion rate and alkene selectivity while reducing the selectivity of by-products to provide excellent catalytic activity and crushing It relates to a dehydration catalyst with improved mechanical properties such as strength, a method for preparing the same, and a method for preparing an alkene using the same.

The alumina catalyst in the form of aluminum oxide is used as an acid catalyst through a unique acid site in the catalyst industry or as an active ingredient dispersant for organic/inorganic catalysts based on high stability.

In general, the alumina catalyst uses aluminum hydroxide or an acid precursor as a starting material to obtain alumina of various phases (crystal phase) through a sintering process, and it is known that a stable alumina crystalline phase is formed as the sintering temperature increases.

Therefore, when industrially high crushing strength or chemical resistance/corrosion resistance was required, a stable alumina phase was induced and used through a high-temperature firing process.

However, although the alumina crystalline phase obtained by high-temperature sintering as described above has higher stability than the alumina crystalline phase obtained by low-temperature sintering, the intrinsic acid point and large specific surface area as a dispersant, which are the characteristics of actual alumina, are significantly reduced, and thus usefulness as a catalyst has the problem of rapidly decreasing.

In addition, conventionally, as a catalyst for isopropyl alcohol dehydration, only gamma-phase alumina formed at a relatively low temperature showed effective activity, and theta-phase and alpha-phase alumina formed at a relatively high temperature had a problem in that the activity was significantly reduced.

Accordingly, there is a need for the development of a catalyst that has an effective activity as a catalyst for isopropyl alcohol dehydration reaction like a gamma-phase alumina catalyst and has excellent crushing strength and corrosion/chemical resistance.

European Patent No. 3092211

In order to solve the problems of the prior art as described above, the present invention improves the conversion rate of starting materials such as alcohol, particularly isopropyl alcohol and the selectivity of propylene, while reducing the selectivity of C3 or more by-products to provide excellent catalytic activity and crushing at the same time An object of the present invention is to provide a dehydration catalyst with improved mechanical properties such as strength, a method for preparing the same, and a method for preparing an alkene.

The above and other objects of the present invention can all be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a dehydration catalyst characterized in that it is a mixed-phase alumina comprising 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina do.

The dehydration catalyst is preferably an alcohol dehydration catalyst, more preferably an isopropyl alcohol dehydration catalyst.

In addition, the present invention comprises the steps of calcining an alumina precursor; steam treatment with a mixture of water vapor and nitrogen after the sintering step; and calcining after the steam treatment step to obtain mixed-phase alumina comprising 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina; A method for preparing a reaction catalyst is provided.

The method for preparing the dehydration catalyst is preferably a method for preparing an alcohol dehydration catalyst, and more preferably a method for preparing an isopropyl alcohol dehydration catalyst.

The present invention also provides a method for producing an alkene, characterized in that the alcohol is dehydrated in the presence of the catalyst.

The alcohol and alkene are preferably isopropyl alcohol and propylene, respectively.

According to the present invention, the selectivity of a starting material such as alcohol, particularly isopropyl alcohol, and a product such as alkene, particularly propylene, is improved while the selectivity of a by-product is reduced, thereby providing excellent catalytic activity and mechanical properties such as crushing strength. There is an effect of providing the improved dehydration catalyst and a method for preparing the same.

Specifically, the isopropyl alcohol dehydration catalyst and its It has the effect of providing a manufacturing method.

In addition, there is an effect of providing a method for producing alkene or propylene, which has excellent process efficiency by improving the selectivity of alkene or propylene.

1 is an XRD (X-ray diffraction) analysis graph of the isopropyl alcohol dehydration catalyst prepared in Example 1 of the present invention.
Figure 2 is an XRD (X-ray diffraction) analysis graph of the isopropyl alcohol dehydration catalyst prepared in Example 2 of the present invention.
3 is an XRD (X-ray diffraction) analysis graph of the isopropyl alcohol dehydration catalyst prepared in Comparative Example 1 of the present invention.
4 is an XRD (X-ray diffraction) analysis graph of the isopropyl alcohol dehydration catalyst prepared in Comparative Example 2 of the present invention.

Hereinafter, the dehydration catalyst of the present disclosure, a method for preparing the same, and a method for preparing an alkene using the same will be described in detail.

When the various crystalline phases of alumina are adjusted to a specific weight and used for the dehydration reaction of isopropyl alcohol, the present inventors improve the conversion rate of isopropyl alcohol and the selectivity of propylene while reducing the selectivity of by-products to provide excellent catalytic activity and at the same time It was confirmed that the crushing strength was excellent, and based on this, the present invention was completed by further concentrating on research.

The dehydration catalyst of the present invention is characterized in that it is a mixed phase alumina comprising 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina, and in this case, stability due to high crushing strength While this is excellent, there is an advantage in that the catalytic activity is improved.

The dehydration catalyst is preferably an alcohol dehydration catalyst, more preferably an isopropyl alcohol dehydration catalyst.

The mixed-phase alumina may preferably contain 3 to 15% by weight of alpha alumina, 70 to 85% by weight of theta alumina, and 10 to 27% by weight of delta alumina, in which case stability and activity are simultaneously improved, crushing strength, etc. There is an advantage in that the mechanical properties of the

In the mixed phase alumina, alpha alumina may be, for example, 3 to 15% by weight, preferably 5 to 15% by weight, more preferably 5 to 10% by weight based on 100% by weight of mixed phase alumina, within this range There is an advantage in that the activity of the catalyst is improved.

In the mixed-phase alumina, theta alumina may be, for example, 70 to 85% by weight, preferably 70 to 80% by weight, more preferably 70 to 75% by weight, based on 100% by weight of mixed phase alumina, within this range Since the mechanical strength of the catalyst is excellent, there is an advantage in that there is little crushing even in regeneration or catalyst circulation.

In the mixed phase alumina, delta alumina may be, for example, 10 to 27% by weight, preferably 10 to 25% by weight, more preferably 20 to 25% by weight based on 100% by weight of mixed phase alumina, within this range It has excellent mechanical strength such as crushing strength, so it has a strong advantage against external impact.

The mixed-phase alumina may not contain gamma alumina as an example, and in this case, there is an advantage in that high crushing strength and excellent catalytic activity, which are the desired effects of the present invention, are simultaneously expressed.

In the present description, the meaning of not containing gamma alumina means less than 0.5 wt%, preferably 0.1 wt% or less, more preferably 0.01 wt% or less, and specifically, it may not be detected in the XRD analysis data of the present description have.

In addition, the mixed phase alumina may include 1 to 18% by weight of alpha alumina, 65 to 95% by weight of theta alumina, 4 to 34% by weight of delta alumina, and 0% by weight of gamma alumina, in which case it is known as an inverse relationship There is an advantage in that the activity and strength of the catalyst are excellent at the same time.

In this description, the weight of alpha, theta, delta, and gamma alumina is 10-80° (step: 0.05°) using an X-ray diffraction analyzer with Bruker's Cu radiation (30 kV, 10mA). , measurement time for each step: 1 s), the XRD graph is obtained, and the structure is analyzed through Rietveld refinement using the XRD analysis data to obtain the content ratio (wt%).

The catalyst of the present disclosure is a mixed-phase alumina having an excess of theta phase, and has advantages in both mechanical strength such as crushing strength and catalytic activity, and is particularly suitable as a catalyst driven at a high temperature.

For reference, it is known that the activity decreases in the order of gamma alumina, delta alumina, theta alumina, and alpha alumina, but the strength of the catalyst increases in inverse proportion. At the same time, there are advantages.

The catalyst may have a conversion rate of, for example, starting material or alcohol of 95% or more, preferably 95 to 100%, more preferably 98.5 to 99.9%, even more preferably 99.4 to 99.9%, within this range. There is an advantage in that process efficiency is improved.

As a specific example of the catalyst, the conversion of isopropyl alcohol (IPA) may be 95% or more, preferably 95 to 100%, more preferably 98.5 to 99.9%, even more preferably 99.4 to 99.9%, in this range There is an advantage in that the process efficiency is improved in the

The catalyst may have, for example, a product or alkene selectivity of 95% or more, preferably 98.8 to 100%, more preferably 99.1 to 99.9%, and has the advantage of increasing process efficiency within this range.

As a specific example, the catalyst may have a propylene selectivity of 95% or more, preferably 98.8 to 100%, more preferably 99.1 to 99.9%, and has the advantage of increasing process efficiency within this range.

The catalyst may have a by-product selectivity calculated by the following Equation 3 as an example of 5% or less, preferably greater than 0 to 3%, more preferably 0.1 to 1%, and the efficiency of the downstream separation process within this range This has the advantage of being improved.

[Equation 3]

By-product selectivity = [(number of moles of by-product)/(number of moles of reacted starting material or alcohol)]*100

The by-product selectivity is preferably C3 or more by-product selectivity, wherein the C3 or more by-product may be a compound having 3 or more carbon atoms, and for example, it may be diisopropyl ether (DIPE).

In addition, the conversion, selectivity, and by-product selectivity can be obtained using gas chromatography, for example.

The catalyst may have, for example, a crushing strength of 63 N or more, preferably 70 N or more, more preferably 70 to 100 N, and has excellent mechanical properties within this range.

In this description, the crushing strength was measured as crushing strength, the maximum force endured by pressing a single particle at a constant speed of 0.01 mm/s using a Texture Analyzer (model name: TA-XT2 Plus, Stable Micro System). Dogs, or two or more particles were measured and the average value was used.

The catalyst may have, for example, a specific surface area of 30 m ² /g or more, preferably 35 m ² /g or more, more preferably 35 to 85 m ² /g, and within this range, catalytic activity, catalytic strength and There is an advantage of excellent catalyst stability.

In the present description, the specific surface area can be obtained by measuring the amount of nitrogen adsorption/desorption according _{to partial pressure (0.10<p/p 0} <0.25) using, for example, BELSORP-mini II (Mictrotrac-BEL).

The catalyst may have, for example, a pore volume of 0.60 cm ³ /g or less, preferably 0.45 to 0.55 cm ³ /g, and has advantages of excellent catalyst activity, catalyst strength and catalyst stability within this range.

In the present description, the pore volume may be calculated as an adsorption amount at _{a partial pressure of 0.99 (p/p 0} ) using, for example, BELSORP-mini II (Mictrotrac-BEL).

The alumina catalyst may contain, for example, a halogen component in an amount of 0.5 wt% or less, or 0.1 to 0.4 wt%, in this case, there is an advantage in that the activity of the catalyst is improved.

The halogen component, preferably chlorine, is combined with the aluminum element of the alumina catalyst to weaken the properties of the Lewis acid of the alumina itself, thereby facilitating the desorption of the product, and thus has the effect of suppressing the generation of by-products.

In the present description, the halogen component may be measured by an inductively coupled plasma (ICP) method.

Hereinafter, a method for producing the dehydration catalyst of the present invention will be described, and in the following description of the production method, all of the contents of the dehydration reaction catalyst of the present invention are included.

The method for preparing the dehydration catalyst of the present invention includes, for example, calcining an alumina precursor; steam treatment with a mixture of water vapor and nitrogen after the sintering step; and calcining after the steam treatment step to obtain mixed-phase alumina comprising 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina; in this case Stability and catalyst activity are improved at the same time, and there is an advantage in that it is possible to prepare an alumina catalyst having high mechanical strength and corrosion/chemical resistance.

In another example, the method for preparing the dehydration catalyst includes the steps of: obtaining a first alumina by first calcining an alumina precursor; steam treatment at a temperature lower than the firing temperature with water vapor after the firing; and 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina by performing secondary calcination at a temperature higher than the steam treatment temperature and lower than the first calcination temperature after the steam treatment step and obtaining a mixed-phase alumina to

The method for preparing the dehydration catalyst is preferably a method for preparing an alcohol dehydration catalyst, and more preferably a method for preparing an isopropyl alcohol dehydration catalyst.

The first calcination step may be, for example, calcining an alumina precursor at a first calcination temperature. In this case, there is an advantage in that it is easy to prepare a catalyst having high crushing strength.

The alumina precursor is not limited as long as it is a material capable of providing an alumina crystal phase by calcination, but may be, for example, at least one selected from Gibbsite, Bayerite, Boehmite, and Diaspore. In this case, there is an advantage in that the crushing strength of the prepared catalyst is improved.

The primary calcination temperature may be, for example, 800 to 1100 °C, preferably 850 to 1100 °C, more preferably 950 to 1000 °C, and within this range, mixed phase alumina having an excess of theta phase among various crystalline phases is prepared. There is an advantage in that the mechanical strength of the catalyst is improved.

The primary firing step may be, for example, firing for 8 to 12 hours, preferably 9 to 11 hours, and more preferably 9 to 10 hours, within this range, there is no structural change due to heat and excellent mechanical strength. Thus, it has a strong advantage against external shocks.

The steam treatment step may be, for example, a step of activating by steam treatment at a temperature lower than the first firing temperature with water vapor after the first firing step.

In the present description, steam treatment means supplying water vapor (steam) into the reactor by adjusting the inside of the reactor to a specific temperature and using nitrogen as a moving gas.

The steam treatment may be, for example, supplying water vapor and nitrogen into the reactor simultaneously in the presence of the mixed-phase alumina in the reactor.

The mixing ratio of water vapor and nitrogen is, for example, N ₂ :H ₂ O in a volume ratio of 1500:1 to 10000:1, more preferably 2000:1 to 3000:1, and excellent mechanical properties within this range. There is an advantage in that the activity of the catalyst is improved while maintaining strength and chemical resistance.

In addition, the mixing ratio of the first alumina and water vapor may be, for example, preferably 1:0.01 to 1:100 by weight of the first alumina and water vapor, and in another example, water vapor (H ₂ O) based on 75 g of the first alumina may be 0.026 to 0.1 g/min, and has high mechanical strength and corrosion resistance/chemical resistance within this range, so that it is possible to prepare an alumina catalyst having excellent stability and high catalytic activity.

The steam treatment temperature may be, for example, a temperature lower than the primary sintering temperature, and preferably within a temperature range lower than the secondary sintering temperature to be described later.

The steam treatment temperature may be, for example, the temperature in the reactor, and as a specific example, it may be in the range of 200 to 500 °C, preferably 300 to 450 °C, and optimal for calcination in the secondary calcination step to be described later within this range. There is an advantage that can provide the activation of.

The activation step may be, for example, steam treatment for 1 to 10 hours, preferably 3 to 6 hours, within this range, the catalyst has excellent stability and high catalytic activity due to high crushing strength and corrosion resistance/chemical resistance There is an advantage that the preparation of an alumina catalyst is possible.

The secondary firing step may be, for example, firing within a temperature range higher than the steam treatment temperature and lower than the first firing temperature after the activation step.

The secondary calcination temperature may be, for example, in the range of more than 500 °C to 600 °C or less, preferably more than 500 °C to 580 °C or less, more preferably in the range of 520 to 580 °C, in this range, the activation in the steam treatment step. There is an advantage of improving the catalytic activity and stability of the mixed phase alumina.

The secondary calcination step may be, for example, calcining for 3 to 7 hours, preferably 3 to 6 hours, more preferably 4 to 6 hours, within this range, the conversion rate of isopropyl alcohol and the selectivity of propylene It is advantageous to provide an alumina catalyst with a reduced by-product selectivity over C3 while further improving the C3.

The method for preparing an alkene of the present disclosure may be, for example, dehydrating alcohol in the presence of the alcohol dehydration catalyst described above.

As a preferred example, the method for preparing an alkene according to the present disclosure may be, for example, dehydrating isopropyl alcohol in the presence of the above-described isopropyl alcohol dehydration catalyst. In this case, the alkene production method may be referred to as a propylene production method.

The dehydration reaction may be, for example, performing the reaction while passing a starting material such as alcohol through a reactor filled with the dehydration alumina catalyst of the present disclosure.

As a preferred example, the dehydration reaction may be performed while passing isopropyl alcohol through a reactor filled with the isopropyl alcohol dehydration alumina catalyst of the present invention.

As a specific example, the dehydration reaction comprises the steps of charging the catalyst of the present invention in a reactor; and performing a dehydration reaction while continuously passing an alcohol, preferably isopropyl alcohol, through the reactor filled with the catalyst.

The reactor is not particularly limited as long as it is a reactor used in the art, and may be, for example, a metal tube type reactor, a multi-tube type reactor, or a plate type reactor.

The catalyst may be charged, for example, in an amount of 10 to 50% by volume, or 10 to 25% by volume of the internal volume of the reactor.

The dehydration reaction may be performed, for example, at 200 to 400 ° C. and 10 to 30 atmospheres, and within this range, the energy cost is not significantly increased and the reaction efficiency is excellent, so that the productivity of the product such as propylene is excellent. .

As a specific example, the dehydration reaction may be carried out at 200 to 400 °C, preferably at 250 to 320 °C.

In addition, the dehydration reaction may be carried out at 10 to 30 atmospheres, preferably 15 to 25 atmospheres.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such variations and modifications fall within the scope of the appended claims.

[Example]

Example 1

The first alumina was obtained by calcining boehmite at 950° C. under an air atmosphere for 10 hours, and after charging the first alumina in a tubular reactor, the temperature was adjusted to 400° C., and then steam and nitrogen were introduced into the reactor. It was steam-treated by supplying for 3 hours. At this time, water vapor was supplied at 0.026~0.1 g/min using an HPLC pump, nitrogen was supplied at 133 ml/min using a Mass Flow Controller (MFC), and the mixing ratio of nitrogen and water vapor was N ₂ :H ₂ O by volume. ₂ :H ₂ O=2500:1, and the weight ratio of water vapor: first alumina was 0.01 to 100:1. In addition, after steam treatment, calcination was performed at 550° C. for 5 hours to obtain an alumina catalyst comprising 5 wt% of alpha alumina, 70 wt% of theta alumina, 25 wt% of delta alumina, and 0 wt% of gamma alumina.

Example 2

It was carried out in the same manner as in Example 1, except that Boehmite was first calcined at 1100°C. As a result, an alumina catalyst comprising 10% by weight of alpha alumina, 70% by weight of theta alumina, 20% by weight of delta alumina and 0% by weight of gamma alumina was obtained.

Comparative Example 1

100% gamma-phase alumina was obtained by calcining boehmite at 550° C. under an air atmosphere for 10 hours.

Comparative Example 2

100% gamma-phase alumina was obtained by calcining boehmite at 550° C. under an air atmosphere for 10 hours. After filling the gamma-phase alumina in a tubular reactor, the temperature was adjusted to 400° C., and then steam and nitrogen were introduced into the reactor 3 It was fed for a period of time and treated with steam. At this time, water vapor was supplied at 0.026~0.1 g/min using an HPLC pump, nitrogen was supplied at 133 ml/min using MFC, and the mixing ratio of nitrogen and water vapor was N ₂ :H ₂ O by volume, N ₂ :H ₂ O =2500:1, and the weight ratio of water vapor to gamma-phase alumina was 0.01 to 100:1. Also, after steam treatment, it was calcined at 550° C. for 5 hours to obtain an alumina catalyst containing 100% gamma-phase alumina.

[Test Example]

The properties of the catalysts prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were measured by the following method, and the results are shown in Tables 1 and 2 below.

Test Example 1: Catalytic reaction evaluation

The prepared catalysts were evaluated for catalytic activity through the dehydration reaction of iso-propyl alcohol (IPA) to produce propylene.

Specifically, 0.75 to 1.5 g of the prepared catalyst was put into a 1-inch fixed bed reactor, and 0.01 to 0.1 g/min of isopropyl alcohol was passed through the reactor to perform the reaction.

At this time, the conditions in the fixed bed reactor were a pressure of 20 atm, a reaction temperature of 280° C., and a WHSV of 0.7h ^-1 . After the IPA dehydration test, the IPA conversion rate (calculated by Equation 1 below), propylene using gas chromatography connected to the reactor Selectivity (calculated by Equation 2 below) and by-product selectivity (calculated by Equation 3 below) were obtained, and the measurement results are shown in Table 1 below.

[Equation 1]

Conversion (%) = [(number of moles of reacted IPA)/(number of moles of supplied IPA)]*100

[Equation 2]

Selectivity (%) = [(number of moles of propylene produced)/(number of moles of reacted IPA)]*100

[Equation 3]

By-product selectivity (%) = [(number of moles of by-product)/(number of moles of reacted starting material or alcohol)]*100

division IPA Conversion Rate (%) Propylene selectivity (%) C3 ≤ By-product selectivity (%) Example 1 99.4 99.1 <1.0 Example 2 98.5 98.8 <1.0 Comparative Example 1 98.2 99.0 <1.0 Comparative Example 2 98.0 99.0 <1.0

As shown in Table 1, the alumina catalysts according to Examples 1 and 2 of the present invention have IPA conversion rates and propylene selectivity equal to or greater than those of the alumina catalysts having 100% gamma-phase alumina (Comparative Examples 1 and 2), and the same selection of by-products It could be confirmed that the figure has

In addition, the alumina catalysts according to Examples 1 and 2 of the present invention had the effect of improving the process efficiency by the excellent IPA conversion rate and propylene selectivity.

Similarly, the catalysts according to Examples 1 and 2 had the effect of increasing the separation efficiency of the downstream separation process due to the low by-product selectivity. For reference, the downstream separation process is a process for separating water and by-products generated in the dehydration reaction, and specifically, it is a process for separating water and by-product DIPE by liquefying it by lowering the temperature at the rear end of the reactor. Therefore, as the number of by-products in the downstream separation process is small, the separation efficiency is increased.

Test Example 2: Evaluation of crushing strength

In order to evaluate the crushing strength of the prepared catalysts, the maximum force endured by pressing a single particle at a constant speed of 0.01mm/s using a Texture Analyzer (model name: TA-XT2 Plus, Stable Micro System) was measured as the crushing strength, For each sample, 10 or more particles were measured and an average value was used, and the measurement results are shown in Table 2 below.

division Crushing strength (N/grain) Example 1 80 or more Example 2 over 83 Comparative Example 1 45 or more Comparative Example 2 45 or more

As shown in Table 2, it was confirmed that the alumina catalysts according to Examples 1 and 2 of the present invention had significantly superior crushing strength compared to the alumina catalysts containing 100% gamma-phase alumina (Comparative Examples 1 and 2).

Combining the above results, it was confirmed that the mixed-phase alumina, which is the alumina catalyst of the present invention, has a catalytic activity equal to or more than that of an alumina catalyst containing 100% gamma-phase alumina, while mechanical strength such as crushing strength is remarkably excellent. In addition, through these results, the alumina catalyst of the present invention can replace gamma-phase alumina used as a catalyst for isopropyl alcohol dehydration reaction in the prior art.

Claims (14)

A mixed phase alumina comprising 1 to 18% by weight of alpha alumina, 65 to 95% by weight of theta alumina and 4 to 34% by weight of delta alumina
dehydration catalyst. According to claim 1,
The dehydration catalyst is an alcohol dehydration catalyst, characterized in that
dehydration catalyst. 3. The method of claim 2,
The alcohol is isopropyl alcohol, characterized in that
dehydration catalyst. The method of claim 1,
The mixed phase alumina, characterized in that it does not contain gamma alumina
dehydration catalyst. 3. The method of claim 2,
The catalyst is characterized in that the conversion of alcohol is 95% or more
dehydration catalyst. 3. The method of claim 2,
The catalyst is characterized in that the alkene selectivity is 95% or more
dehydration catalyst. The method of claim 1,
The catalyst is characterized in that the by-product selectivity is 5% or less
dehydration catalyst. The method of claim 1,
The catalyst is characterized in that the crushing strength is 63N or more
dehydration catalyst. According to claim 1,
The catalyst has a specific surface area of 30 m ² /g or more
dehydration catalyst. According to claim 1,
The catalyst is characterized in that the pore volume is 0.60 cm ^{3 /g or less}
dehydration catalyst. calcining the alumina precursor; steam treatment with a mixture of water vapor and nitrogen after the sintering step; and calcining after the steam treatment step to obtain mixed-phase alumina comprising 1 to 18 wt% of alpha alumina, 65 to 95 wt% of theta alumina, and 4 to 34 wt% of delta alumina.
A method for preparing a dehydration catalyst. 12. The method of claim 11,
The alumina precursor is characterized in that at least one selected from Gibbsite, Bayerite, Boehmite, and Diaspore.
A method for preparing a dehydration catalyst. The dehydration reaction of alcohol in the presence of the catalyst of any one of claims 1 to 10, characterized in that
A process for the preparation of alkenes. 14. The method of claim 13,
The dehydration reaction is characterized in that 200 to 400 ℃, characterized in that carried out under 10 to 30 atmospheres
A process for the preparation of alkenes.

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