KR20160014180A - Method for Producing Alumina Carrier with Different Crystalline Phase for Catalyst for Direct Dehydrogenation of n-Butane, Platinum-Tin Bimetallic Catalyst Supported by the Alumina Carrier, and Method of Producing n-Butene and 1,3-Butadiene Using Said Catalyst - Google Patents

Abstract

The present invention relates to a method for producing an alumina carrier with a different crystalline phase for a direct dehydrogenation catalyst by an epoxide-based sol-gel process to manufacture n-butene and 1,3-butadiene from n-butane; a method for producing a platinum-tin bimetallic catalyst supported by the alumina carrier using the alumina carrier produced by the epoxide-based sol-gel process; and a method for producing n-butene and 1,3-butadiene using the catalyst produced thereby. More specifically, the present invention relates to a method for producing a catalyst which uses platinum as an active component and contains tin by synthesizing an alumina carrier, which is known to be suitable for direct dehydrogenation of n-butane, as a carrier to support the same by an epoxide-based sol-gel process and making the heat treatment temperature different; a method for producing a platinum-tin bimetallic catalyst supported by the alumina carrier by sequentially supporting tin and platinum in the alumina carrier; and a method for producing n-butene and 1,3-butadiene with a high added value through direct dehydrogenation from low-priced n-butane using the catalyst produced thereby.

Description

A method for producing an alumina support for direct dehydrogenation reaction of n-butane having various crystal phases, a platinum catalyst containing tin supported on the alumina support prepared thereby, and a catalyst for preparing n-butene and 1,3-butadiene using the catalyst Method for Producing Alumina Carrier with Different Crystalline Phase for Catalyst for Direct Dehydrogenation of n-Butane, Platinum-Tin Bimetallic Catalyst Supported by Alumina Carrier, and Method of Producing n-Butene and 1,3-Butadiene Using Said Catalyst}

The present invention relates to a process for preparing an alumina support for a direct dehydrogenation catalyst of n-butane having various crystalline phases by an epoxide-based sol-gel process, a process for producing an alumina support by sequentially carrying tin and platinum on the alumina support, Tin, and a process for producing n-butene and 1,3-butadiene using the catalyst.

Butadiene refers to a gas that can be obtained by extraction from C4 oil, which is usually produced in about 10% of the Naphtha Cracking Center (NCC: Naphtha Cracking Center), or dehydrogenation of butane, and which has a characteristic odor at room temperature. The mixed C 4 fraction is extracted through the natural (shale) gas process (ECC: Ethane Cracking Center). When 1,3-butadiene separated by the extractive distillation method is limited by using dimethylformamide (DMF) It is often called butadiene.

The butadiene thus obtained is an important material as a raw material for synthetic rubber and is mainly used as a raw material for butadiene styrene rubber (SBR), butadiene acrylonitrile rubber (NBR), and polybutadiene (BR). It is also used as a raw material for chloroprene, adiponitrile, maleic anhydride and the like. The main clients of synthetic rubber are tire, shoe and other industrial rubber products manufacturers. The major customers of latex products are the paper industry and the carpet industry.

Currently, most of the butadiene can be obtained through the naphtha cracking plant. The naphtha cracking plant refers to an industry that produces naphtha and produces basic oils such as ethylene and propylene. The proportion of the products produced through the naphtha cracking plant is usually 31% of ethylene, 15% of propylene, 10% of C4 oil (butadiene raw material), 14% of RPG (benzene / toluene / xylene raw material) Other products are 29%. At this time, ethylene and propylene go directly to the production process of the induction product. C4 oil and RPG are further extracted and purified to produce useful petrochemical base oil such as butadiene, benzene, toluene, and xylene.

As described above, most of the butadiene production is produced by the naphtha cracking plant. In accordance with the development of the shale gas, activation of the natural (shale) gas process (ECC) facility, production of butadiene based on the naphtha cracking plant But the price of butadiene is expected to rise in the future. In addition, the surge in tire production in emerging countries such as China and India and the increase in imports of automobiles in Eastern Europe are expected to increase demand for synthetic rubber, which is a major demand source for butadiene. Since the production of new routes for butadiene is limited, stable supply of butadiene Is thought to be important.

Currently, most of the butadiene is obtained from the naphtha cracking plant, but as mentioned above, this process mainly produces basic oils such as ethylene and propylene and can not be optimized for the production of butadiene. Therefore, the production of butadiene by the present naphtha cracking plant has a limitation in meeting the supply and demand of butadiene, and in the long run, imbalance in supply and demand is inevitable. Therefore, alternative process technology that can produce a large amount of butadiene demand is in urgent need.

Therefore, the technology to produce n-butene and butadiene through the dehydrogenation reaction of n-butane as a process that can concentrate only on butadiene production as a sole process, overcoming the limitation that such naphtha cracking process can not be optimized for butadiene production And research on this is underway (Non-Patent Documents 1 to 4).

The dehydrogenation reaction of n-butane removes hydrogen from n-butane to produce dehydrogenation products (TDP: total dehydrogenation products, n-butene and butadiene), and direct dehydrogenation Butane is an exothermic reaction and stable water is produced after the reaction. Therefore, the thermodynamic reaction of the n-butane with an oxidative dehydrogenation reaction can be divided into two types: However, due to the use of oxygen, by-products such as carbon monoxide and carbon dioxide through the oxidation reaction are produced, which is disadvantageous in terms of selectivity and yield of the dehydrogenation product rather than the direct dehydrogenation reaction of n-butane. On the other hand, the direct dehydrogenation reaction of n-butane is an endothermic reaction requiring higher temperature reaction conditions than the oxidative dehydrogenation reaction, and a noble metal catalyst such as platinum is used. Since the catalyst has a very short life span, However, it is known as an advantageous process in terms of selectivity and yield of dehydrogenation products (Patent Documents 1 to 4, Non-Patent Documents 5 to 9).

Therefore, if a dehydrogenation product is produced using a direct dehydrogenation reaction process of n-butane instead of a naphtha cracking process, it can be an effective alternative to produce a dehydrogenation product by a single process.

However, according to the above-mentioned, the direct dehydrogenation reaction of n-butane is advantageous in terms of selectivity and yield of dehydrogenation product compared with the oxidative dehydrogenation reaction, but the lifetime of the catalyst is short, it is expected that a problem of inactivation due to coking deposition is expected. Therefore, it is important to develop a catalyst capable of maintaining long-term performance of the catalyst while maintaining the conversion of n-butane to a high degree of selectivity and inhibiting deactivation by caulking deposition for effective dehydrogenation product production.

Alumina-based catalysts (Patent Documents 1 to 4, Non-Patent Documents 5 to 9), chromium-alumina-based catalysts (Patent Documents 1 to 4), etc. have been used to produce dehydrogenation products by direct dehydrogenation reaction of n-butane, Patent Documents 5 and 6, and Non-Patent Document 9), and vanadium-based catalysts (Non-Patent Documents 10 and 11). The production of dehydrogenation products by dehydrogenation of paraffins has been studied since the late 1930s, and the dehydrogenation reaction of n-butane during chrome-alumina series during octane production to increase octane number of fuel during World War II A process for producing C4 dehydrogenation products using a catalyst has been developed in the beginning. Since the 1960s, the dehydrogenation process of n-butane using a platinum-based platinum-alumina catalyst, which is a noble metal, has been continuously developed and studied. In the 2000s, vanadium-based catalysts have been developed as catalysts for replacing expensive noble metal catalysts . Among these catalysts, catalysts which are mainly used for direct dehydrogenation of n-butane and which exhibit the highest activity are platinum-alumina-based catalysts and are known to be suitable catalysts for this reaction (Non-Patent Document 9).

In general, the above-mentioned platinum-alumina catalyst is prepared in the form that platinum is supported on alumina. More specifically, 0.2 g of a platinum / alumina catalyst prepared by supporting platinum using gamma-alumina carrier (g-Al ₂ O ₃ ) Butane under the conditions of hydrogen: n-butane = 1.25: 1, total flow rate 18 ml · min ^-1 , reaction temperature 530 ℃, Butane conversion of 45%, dehydrogenation product selectivity of 53% and yield of 24%. After 2 hours of reaction, the conversion of n-butane to 10%, the dehydrogenation product It was reported that the selectivity was 50% and the yield was 5% (Non-Patent Document 12).

When the enhancer is used for the platinum-alumina catalyst, the activity can be improved by changing the state depending on the interaction between the platinum, the enhancer and the alumina support. The tungsten is mainly used as the activity enhancer and stabilizer for the platinum, , Platinum-tin-alumina catalysts obtained by carrying platinum and tin in a direct dehydrogenation reaction of n-butane have been reported to exhibit high activity. Specifically, the results of the direct dehydrogenation reaction of n-butane using 0.2 g of a platinum-tin / alumina catalyst prepared by sequentially carrying platinum and tin using a gamma alumina carrier (g-Al ₂ O ₃ ) Butane dehydrogenation reaction was carried out under the condition that the reactant injection ratio was hydrogen: n-butane = 1.25: 1, the total flow rate was 18 ml · min ^-1 , and the reaction temperature was 530 ° C. After 10 minutes of reaction, Butane conversion of 43%, dehydrogenation product selectivity of 78% and yield of 34% were obtained. After 2 hours of reaction, it was reported that the conversion of n-butane was 13%, the dehydrogenation product selectivity was 86%, and the yield was 11% Non-Patent Document 12). In addition, a literature using platinum-alumina catalysts other than tin as copper and palladium has been reported (Non-Patent Document 13), in which platinum-copper / alumina catalysts were prepared by supporting platinum and copper on alumina , after the catalyst 0.1g at 500 ℃ reduced 2 hours hydrogen flow rate of 10 ml · min ^-1, the reactant flow ratio of n-butane: hydrogen: nitrogen = 1: 1: 1, space velocity (GHSV) 18000 ml · h ^{- 1} -g _cat ^-1 , and a reaction temperature of 500 ° C, the dehydrogenation reaction of n-butane was carried out. The platinum-copper / alumina catalyst containing 1% by weight of platinum and 1% by weight of copper had a n-butane conversion of 20.1% and a dehydrogenation product selectivity of 86.9% after 3 minutes of reaction, and after 300 minutes of reaction, It was reported that the conversion rate was 18.8% and the dehydrogenation product selectivity was 92.2%. The platinum-palladium-copper / alumina catalyst prepared by carrying 0.5% by weight of platinum, 0.5% by weight of palladium and 2% by weight of copper in alumina under the same conditions, showed that after 3 minutes of reaction, the conversion of n-butane to 20.5% 92.2% of product selectivity was obtained, and after 300 minutes of reaction, it was reported that the conversion of n-butane was 19.5% and the dehydrogenation product selectivity was 96.1%.

In addition, the platinum-tin-alumina catalyst improves the activity in the direct dehydrogenation reaction of n-butane through the addition of a catalyst, thereby obtaining a dehydrogenation product with high selectivity and yield. (Non-Patent Document 14), in this document, magnesium aluminate was synthesized by synthesizing alumina and magnesia, platinum, tin and indium were supported on the magnesium aluminate support, and platinum-tin-indium / magnesium aluminate Catalyst. Tin-platinum 0.3 wt%, 0.37 wt.% Tin, platinum be prepared containing the indium 0.28 percent by weight after the indium / magnesium aluminate catalyst 0.2g reduction for 3 hours at 530 ℃ with hydrogen, the total flow rate of 18 ml · min ^-1 , The dehydrogenation product yield of 29% was obtained after 10 minutes of reaction under the conditions of the reaction product injection ratio of hydrogen: n-butane = 1.25: 1, and the dehydrogenation product yield of 27% was obtained after 120 minutes of reaction. In addition, a literature on utilization of zirconium-introduced catalysts has been reported (Non-Patent Document 15). In this document, platinum-tin / zirconia-alumina catalysts were prepared, hydrogen: nitrogen = 1: 10 and then reduced to, total flow 120 cm ³ · min ^-1, the reactant flow ratio of hydrogen: n-butane = 3: 1 in the condition, the initial reaction of n-butane conversion of 22.4%, a dehydrogenation product It was reported that the selectivity was 98.9%.

In the direct dehydrogenation reaction of n-butane, when a platinum-tin-alumina catalyst containing platinum and tin supported on alumina is used, dehydrogenation products of high selectivity and yield can be obtained, There is a need to develop a catalyst capable of maintaining the performance of the catalyst for a long period of time because deactivation by coking deposition appears and high activity of the catalyst is not maintained for a long time.

US 6,433,241 B2 (A. Wu, C. A. Drake) 2002.8.13. US 6,187,984 B1 (A. Wu, C. A. Drake) 2001.2.13. US 5,344,805 (G.P. Khare, R.A. Porter) 1993.5.3. US 4,827,072 (T. Imai, H. Abrevaya, J. C. Bricker, D. Jan) 1988.7.20. US 3,960,975 (H.E. Manning) 1974.6.3. US 3,960,776 (M. C. Ellis, H. E. Manning) 1974.7.1.

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Accordingly, the present inventors have devised a process for producing an alumina support in order to minimize the problem of reduction in activity over time of the platinum-tin-alumina catalyst that has been revealed in the prior art. The platinum / A manufacturing technique for tin / alumina catalysts has been established. The catalytic reaction process was developed to produce dehydrogenation products with high selectivity and yield by inhibiting inactivation by using the catalyst thus prepared. In addition, by establishing a technique for producing a platinum / tin / alumina catalyst through a simple process, reproducibility in the production of a catalyst is ensured.

Accordingly, an object of the present invention is to provide a catalyst for preparing a catalyst using various crystalline alumina as a carrier for supporting platinum as an active ingredient and tin as a promoter, and is applicable to a direct dehydrogenation reaction of n-butane The present invention relates to a process for preparing a catalyst capable of obtaining a high activity and a process for producing a catalyst having reproducibility. The process comprises preparing an alumina support of various crystalline phases by using an epoxide-based sol- And supporting the tin and platinum by a continuous impregnation method using the alumina support thus prepared. The present invention also provides a method for producing a platinum catalyst containing tin supported on an alumina support.

It is another object of the present invention to provide a catalyst for the dehydrogenation of n-butane, which comprises a tin-containing platinum catalyst supported on an alumina support produced by the above- And a method for producing the dehydrogenated product.

In order to solve the above problems, the present invention provides a process for preparing an alumina support for a direct dehydrogenation reaction catalyst of n-butane having various crystal phases, comprising the steps of:

(a) dissolving an aluminum precursor in an alcohol solvent;

(b) injecting an epoxide compound into the solution to obtain a gel;

(c) aging the gel at room temperature;

(d) drying the aged gel to remove the alcohol solvent; And

(e) heat treating the dried gel to obtain an alumina support for a direct dehydrogenation catalyst of n-butane having various crystalline phases.

In the method for producing an alumina support for a direct dehydrogenation catalyst of n-butane in accordance with the present invention, the aluminum precursor solution prepared in the step (a) may be added with distilled water May be added.

In the step (a), the aluminum precursor is dissolved in the alcohol solvent to hydrate the aluminum metal ion. The alcohol solvent used in the step (a) is not particularly limited and may be selected from the group consisting of methanol, ethanol Ethanol is most preferred, although representative alcohols such as ethanol, propanol, isopropanol, 1-butanol and 2-butanol can be used.

Examples of the aluminum precursor include aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum fluoride trihydrate, aluminum phosphate hydrate, aluminum hydrate, It is preferable to use at least one selected from aluminum hydroxide precursors, and it is particularly preferable to use aluminum nitrate nonahydrate.

The distilled water used in step (a ') reacts with the aluminum precursor to help hydrate the metal ion, and the gel formation rate is controlled in step (b). The amount of the distilled water used can be used without limitation The molar ratio of distilled water to aluminum precursor is preferably 1 to 8: 1. If the molar ratio is less than 1: 1, the effect of adding distilled water is insufficient. If the molar ratio exceeds 8: 1, gelation occurs excessively, Of the gel is formed.

In the step (b), an epoxide compound is injected into the aluminum precursor solution in step (a) to form a hydroxyl group on aluminum hydrate, and a condensation reaction between them is carried out to form a gel The epoxide compound to be used in the step (b) may be selected from the group consisting of propylene oxide, ethylene oxide and 1,2-epoxybutane, It is preferable to use at least one kind selected.

The aging of the gel in the step (c) is carried out for the purpose of continuing the condensation reaction even after the gel is formed so that the gel grows stronger and firmer while the network grows. For example, the aging is carried out at room temperature (20-25 ° C) For two to three days.

The purpose of drying the gel in the step (d) is to remove the solvent after the aging process of the gel. Generally, the temperature at which the alcohol can be evaporated is set to the lower limit, and the temperature at which the change of the sample by heat And the drying time can also be limited within a time range in which all the alcohol is expected to be removed from the sample. For example, the drying temperature may be carried out at a temperature ranging from 50 to 200 DEG C, preferably from 80 to 120 DEG C for 4 to 5 days.

The heat treatment of the solid sample dried in the step (e) is not only for synthesis as an alumina support, but also taking into consideration the direct dehydrogenation reaction temperature of the n-butane, when the catalyst supported on the carrier is used for the reaction The heat treatment may be performed at a temperature of 350 to 1200 ° C, preferably 600 to 1000 ° C, and most preferably 800 ° C for 1 to 12 hours. When the heat treatment temperature is 350 ° C Or the heat treatment time is less than 1 hour, the aluminum precipitate is not sufficiently synthesized with alumina. Therefore, when the heat treatment temperature exceeds 1200 ° C. or the heat treatment time exceeds 12 hours, the alumina support is directly dehydrated in n-butane It is transformed into a crystalline phase which is not suitable for the digestion reaction or the specific surface area is remarkably reduced, It is not preferable because there is a fear that it will not be used. In this heat treatment step, the crystal phase of the alumina support can be made different by performing the heat treatment at various temperatures.

A process for preparing a platinum catalyst containing tin supported on an alumina support according to the present invention using an alumina support prepared as described above comprises the following steps:

(i) impregnating a tin precursor aqueous solution into an alumina carrier produced by the method for producing a carrier of the present invention as described above;

(ii) drying and heat-treating the resultant obtained in the step (i) to obtain tin supported on an alumina support;

(iii) impregnating the platinum precursor aqueous solution with the tin supported on the alumina support obtained in the step (ii); And

(iv) drying and heat-treating the resultant obtained in the step (iii) to obtain a platinum catalyst containing tin supported on an alumina support.

The tin precursor used in the step (i) may be any of conventional tin precursors which can be used without limitation. Generally, tin chloride, tin nitride, tin bromide, tin oxide, And a tin acetate precursor. It is particularly preferable to use tin chloride (Tin (II) chloride).

The purpose of drying in step (ii) is to remove remaining moisture after tin impregnation. Therefore, the drying temperature and the drying time can be limited according to general moisture drying conditions. For example, 200 ° C, preferably 70 to 120 ° C, and the drying time is 3 to 24 hours, preferably 6 to 12 hours.

The heat treatment in the step (ii) is performed for the purpose of synthesizing tin supported on an alumina support. The heat treatment is performed at a temperature of 400 to 800 ° C, preferably 500 to 700 ° C for 1 to 12 hours, 6 hours. If the heat treatment temperature is less than 400 ° C or the heat treatment time is less than 1 hour, synthesis of tin supported on the alumina support is not sufficient. If the heat treatment temperature exceeds 800 ° C or the heat treatment time exceeds 12 hours There is a possibility that the phase of the tin supported on the alumina support may be denatured.

The platinum precursor used in step (iii) may be any of conventionally used precursors. Generally, platinum precursors include chloroplatinic acid, platinum oxide, platinum chloride, ) And a platinum bromide precursor. It is particularly preferable to use chloroplatinic acid.

The purpose of the thermal drying in the step (iv) is to remove remaining moisture after impregnation with platinum, so that the drying temperature and the drying time can be limited according to general moisture drying conditions. For example, the drying temperature is 50 To 200 ° C, preferably 70 to 120 ° C, and the drying time is 3 to 24 hours, preferably 6 to 12 hours.

In the step (iv), the heat treatment may be performed at a temperature of 400 to 800 ° C. for 1 to 12 hours, preferably at a temperature of 500 to 700 ° C. for 3 to 6 hours, To obtain a platinum catalyst containing tin. The heat treatment of the dried solid sample is not only for obtaining a platinum catalyst containing tin supported on an alumina support but also for taking the reaction temperature of the direct dehydrogenation reaction of n-butane into consideration, When the heat treatment temperature is less than 400 DEG C or the heat treatment time is less than 1 hour, the platinum catalyst containing tin supported on the alumina support is not formed properly, and the heat treatment temperature is preferably 800 DEG C Or the heat treatment time exceeds 12 hours, the crystal phase of the platinum catalyst containing tin supported on the alumina support may be altered, which may not be suitably used as a catalyst.

The present invention also provides a process for preparing a dehydrogenation product through a direct dehydrogenation reaction of n-butane on a platinum catalyst comprising tin supported on an alumina support produced by the above process.

The reaction product of the direct dehydrogenation reaction of the n-butane is a mixed gas containing n-butane and nitrogen, and has a volume ratio of n-butane to nitrogen of 1: 0.2 to 10, preferably 1: 0.5 to 5, and more preferably 1: 1. When the volume ratio of n-butane and nitrogen is out of the above range, deactivation due to coking formation occurs rapidly during the direct dehydrogenation reaction of n-butane, the activity or selectivity of the catalyst is lowered, the dehydrogenation product production is reduced , And process safety may also occur, which is undesirable.

When the reactant in the form of the mixed gas is supplied to the reactor, the amount of the reactant to be injected can be controlled by using a mass flow controller. The amount of the reactant to be injected is preferably in the range of 10 to 6,000 GHz (Gas Hourly Space Velocity) cc · h ^-1 · g _cat ^-1 , preferably 100 to 3000 cc · h ^-1 · g _cat ^-1 , more preferably 300 to 1000 cc · h ^-1 · g _cat ^-1. . If the space velocity is less than 10 cc · h ^-1 · g _cat ^{-1, the} amount of dehydrogenation product produced is too low, and if it exceeds 6000 cc · h ^-1 · g _cat ^-1 , Which is undesirable because rapid deposition of caulking occurs.

The reaction temperature for proceeding the direct dehydrogenation reaction of the n-butane is preferably 300 to 800 ° C, more preferably 500 to 600 ° C, and most preferably 550 ° C. When the reaction temperature is lower than 300 ° C, the reaction of n-butane is not sufficiently activated, and when it exceeds 800 ° C, decomposition reaction of n-butane occurs mainly.

Platinum, which is an active component of a platinum catalyst containing tin supported on an alumina support used for a direct dehydrogenation reaction of the n-butane, can be obtained by reacting n-butene with 1,3-butadiene in a high yield in the direct dehydrogenation reaction of n- And tin acts to increase the amount of active sites for dehydrogenation reaction by preventing the sintering of platinum particles and increasing the degree of dispersion by keeping the particle size of platinum small. Alumina is a carrier for supporting platinum and tin and has high thermal and mechanical stability and is known to be suitable for direct dehydrogenation reaction of n-butane with ability to maintain high platinum dispersion.

According to the present invention, an alumina support can be prepared through an epoxide-based sol-gel method, and reproducibility can be secured in the production of a support. Further, since the platinum catalyst containing tin supported on the finally obtained alumina support can be obtained by a simple method of continuously impregnating, drying and heat-treating tin and platinum to the alumina support, it is possible to use a specific ratio of tin and platinum A platinum catalyst containing tin supported on an alumina support can be easily and simply prepared, its component ratio can be freely controlled, and a highly efficient catalyst can be produced by a method for producing a catalyst according to the present invention, which is thermally and mechanically stable , It is possible to stably obtain a platinum catalyst containing tin supported on an alumina support for a direct dehydrogenation reaction catalyst of a n-butane which can produce reproducibility in the production process of a catalyst and can produce a dehydrogenation product with a high yield have.

Also, since the platinum catalyst containing tin supported on the alumina support produced according to the present invention mainly uses alumina, which is an industrially used carrier, it is easy to process the catalyst, and thus, Therefore, according to the present invention, the demand and value of the petrochemical industry are increasing, and the dehydrogenation product, which is relatively stronger in price compared to the olefin, can be produced from n-butane having a low utilization value, Can be achieved. In addition, the conventional naphtha cracking process can not be optimized for the production of dehydrogenation products, and the direct dehydrogenation process of n-butane, which can concentrate only on the dehydrogenation product production as a single process, And it is advantageous in that it can actively cope with future market changes and can operate efficiently.

1 is a graph showing the results of X-ray diffraction analysis of six catalysts prepared by the method of Production Example 3 of the present invention.
2 is a graph showing the results of X-ray diffraction analysis of the reduced catalysts obtained by reducing the six catalysts prepared by the method of Production Example 3 of the present invention.
FIG. 3 is a view showing acid characteristic profiles of six catalysts prepared by the method of Production Example 3 of the present invention. FIG.
FIG. 4 is a graph showing a change in yield of dehydrogenation products during a 360-minute direct dehydrogenation reaction of n-butane over six catalysts prepared by the method of Production Example 3 of the present invention.
5 is a graph showing the catalytic activity at 360 minutes after direct dehydrogenation of n-butane on six catalysts prepared by the method of Production Example 3 of the present invention.

Hereinafter, the present invention will be described in detail with reference to specific embodiments. However, these examples are for illustrative purposes only, and the present invention is not limited to these examples.

[ Manufacturing example  One]

Epoxide  Based Sol-gel method  Lt; RTI ID = 0.0 > 800 C < / RTI > carrier  (Al ₂ O ₃ )

Ethanol (Ethanol, Fisher product) was used as an alcohol solvent and aluminum nitrate nonhydrate (Aldrich product) was used as an aluminum precursor for alumina carrier preparation. First, 22.1 g of the aluminum precursor was dissolved in 85.9 ml of an ethanol solvent and stirred for 3 hours to sufficiently dissolve the aluminum precursor. Then, 42.6 ml of propylene oxide (product of Arcos) was slowly added to the solution to induce a condensation reaction between metal ions. The solution was further stirred for 5 minutes to obtain white opaque alumina gel (Gel) The alumina gel thus obtained was allowed to aged at room temperature for 2 days. Thereafter, the aged gel was dried in an oven at 80 ° C. for about 5 days, and the thus obtained sample was heat-treated at 800 ° C. for 4 hours in an electric furnace in an air atmosphere to prepare an alumina carrier according to an epoxide-based sol-gel method. The carrier thus prepared was named Al ₂ O ₃ (800).

[ Manufacturing example  2]

Epoxide  Based Sol-gel method  The alumina carrier  ( Al ₂ O ₃ )

In Production Example 2, the same procedures as in Production Example 1 were conducted until the alumina gel was formed, aged and dried, and the heat treatment time was kept at 4 hours, and the temperature was changed to 600 ° C, 700 ° C, 900 ° C, 1000 ° C, and 1100 ° C Five kinds of alumina carriers were prepared by heat treatment. The carrier thus prepared was named Al ₂ O ₃ (X) (X = heat treatment temperature) according to the heat treatment temperature.

[ Manufacturing example  3]

Six types of alumina were used to form a series of tin and platinum Impregnation  Platinum / tin / alumina ( Pt / Sn / Al ₂ O ₃ ) Produce

The platinum / tin / alumina (Pt / Sn / Al ₂ O ₃ ) catalyst was prepared by using six kinds of alumina carriers prepared according to the epoxide-based sol-gel method of Preparation Example 1 and Preparation Example 2, Lt; / RTI >

Specifically, the production method of the six platinum / tin / alumina catalysts is as follows. First, 0.038 g of tin chloride dihydrate (Tin (II) chloride dihydrate) as a tin precursor was charged into a beaker and a small amount of hydrochloric acid (0.37 ml) and distilled water 15 ml). When the tin precursor is completely dissolved in the thus-prepared solution, 2.0 g of the alumina carrier prepared above is added, and the mixture is heated at 70 DEG C while stirring until the distilled water is completely evaporated. Thereafter, the solid material was further dried in an oven at 80 DEG C for about 12 hours, and the thus obtained sample was heat-treated at 600 DEG C for 4 hours in an electric furnace in an air atmosphere to form tin / alumina, Tin / alumina (Sn / Al ₂ O ₃ ).

To 2.0 g of the tin / alumina sample thus obtained, 0.053 g of chloroplatinic acid hexahydrate as a platinum precursor was dissolved in distilled water (10 ml) in a beaker so that the content of platinum was 1 wt% When the precursor solution completely dissolved, 2.0 g of tin / alumina prepared in advance was added to the precursor solution, and the mixture was stirred at 70 캜 until the distilled water completely evaporated. Thereafter, the solid material was further dried in an oven at 80 ° C. for about 12 hours, and the thus obtained sample was heat-treated for 4 hours at 550 ° C. in an electric furnace in an air atmosphere to prepare a platinum / tin / alumina catalyst. The Pt / Sn / Al ₂ O ₃ (600), Pt / Sn / Al ₂ O ₃ (700), Pt / Sn / Al ₂ O ₃ / Al ₂ O ₃ (900), Pt / Sn / Al ₂ O ₃ (1000), and Pt / Sn / Al ₂ O ₃ (1100).

X-ray diffraction analysis of the prepared catalysts confirmed the phase of each catalyst, and the results are shown in FIG. As shown in FIG. 1, the platinum and alumina structures were observed in the six catalysts as a result of the analysis of the catalyst prepared by the method of Production Example 3 of the present invention. In the catalyst having a high heat treatment temperature of the carrier, As the annealing temperature of the alumina support increased, it was confirmed that the alumina changed its crystal phase to gamma, theta and alpha.

FIG. 2 shows the results of X-ray diffraction analysis of the reduced catalyst after the reduction treatment of the prepared catalysts. The crystal phase of the alumina support of the reduced catalyst was the same as that of the heat treated catalyst, and it was confirmed that the crystal phase of platinum changed to the crystal phase of platinum - tin in the case of the catalyst heat treated at a high temperature.

3 is a view showing an acid characteristic profile of the produced catalyst. The acid profile of the catalyst shows the results of ammonia temperature desorption curves. As shown in FIG. 3, it was found that the acid characteristic of the catalyst was weakened as the heat treatment temperature of the alumina support of the catalyst was increased.

Table 1 shows the BET specific surface area of the prepared catalyst and the surface area of platinum as the active metal. The BET specific surface area of the catalyst was obtained from the analysis of the BET equation of BELSORP-mini equipment, and the surface area of platinum was obtained from the results of hydrogen chemisorption analysis of Bel-Cat equipment. As shown in Table 1, the BET specific surface area decreases linearly with the heat treatment temperature of the alumina support of the catalyst, and the surface area of platinum decreases gradually.

[ Example  One]

continuity Flow equation  Direct dehydrogenation of n-butane via catalytic reactor

Direct dehydrogenation of n-butane was carried out using the platinum / tin / alumina catalysts prepared by the methods of Preparation Examples 1 and 3, and the specific reaction conditions were as follows.

The reactant used in the direct dehydrogenation reaction of n-butane in this Example 1 is a C4 mixture containing 99.65% by weight of n-butane, the composition of which is shown in Table 2 above.

For the catalytic reaction, a linear quartz reactor was installed in an electric furnace, the catalyst was charged into a quartz reactor, and a reduction process was performed to activate the catalyst prior to the reaction. In the reduction process, the temperature of the fixed-bed reactor was raised from room temperature to 570 ° C and maintained at 570 ° C for 3 hours. As a reducing gas, a mixture of hydrogen and nitrogen was injected at a ratio (volume ratio) of 1: 1 , And the injection rate was set to 600 cc · hr ^-1 · g _{c at} ^-1 based on hydrogen. Thereafter, the temperature of the reactor was lowered to 550 ° C, and the direct dehydrogenation reaction of n-butane was carried out at 550 ° C by passing the C4 mixture containing the n-butane and nitrogen through the catalyst bed. At this time, the gas for the reaction was injected so that the ratio of n-butane: nitrogen was 1: 1, and the injection rate was 600 cc · hr ^-1 · g _cat ^-1 based on the amount of catalyst and the n-butane Respectively.

The products after the reaction include byproducts (methane, ethane, ethylene, propane, propylene) by cracking in addition to the dehydrogenation products (n-butene and 1,3-butadiene) Butane and i-butene) and n-butane which are unreacted. Therefore, gas chromatography was used for the separation and analysis.

The conversion of n-butane, the selectivity and yield of dehydrogenation products by the direct dehydrogenation reaction of n-butane on the prepared platinum / tin / alumina catalyst were calculated by the following equations (1), (2) and (3).

[ Equation  One]

[ Equation  2]

[ Equation  3]

Direct dehydrogenation of n-butane over the platinum / tin / alumina catalysts obtained in Preparation Examples 1 and 3 was carried out for 360 minutes. The change in dehydrogenation product yield was shown in FIG. 4, Table 3 and FIG. 5 show the results. The results of the selectivity of the catalyst after 360 minutes of the progress of the reaction are shown in Table 4.

As shown in Tables 3 and 4 and FIGS. 4 and 5, in the direct dehydrogenation reaction of n-butane carried out by the Pt / Sn / Al ₂ O ₃ (800) catalyst, the yield of the catalyst is decreased Inactivation. It is considered that deactivation is caused by the caulking deposition of the catalyst as reported in various documents. (N-butene, 1,3-butadiene) was found to be higher than about 90%. Major byproducts were isomerization products (i-butane, i-butene) and cracking materials (methane, ethane, Ethylene, propane, propylene).

[ Example  2]

Manufacturing example  2 and Manufacturing example  3 < / RTI > Pt / Sn / Al ₂ O ₃ (X) (where X is the alumina heat treatment temperature)

Sn / Al ₂ O ₃ (600), Pt / Sn / Al ₂ O ₃ (700), Pt / Sn / Al ₂ O (700) prepared by the method of Production Example 2 and Production Example 3 ₃ (900), after a reduction process in the order of the _{Pt / Sn / Al 2 O 3} (1000), Pt / Sn / Al 2 O 3 (1100)) catalyst for example 1, n-direct dehydration of butane Digestion reaction was carried out.

The results of the reaction test according to Example 2 are shown in Tables 5 and 6 and FIGS. 4 and 5. FIG. 4 shows changes in the yield of dehydrogenation product with time for 360 minutes, and the catalyst activity after 360 minutes of the progress of the reaction is shown in Table 5 and FIG. 5, and the selectivity of the catalyst was shown in Table 6 .

From the results of the above tables and figures it can be seen that Pt / Sn / Al ₂ O ₃ (800) catalysts, especially those prepared by sequential impregnation of tin and platinum with an alumina support of the epoxide-based sol- And the activity of the catalyst increased with increasing the heat treatment temperature. It is shown that Pt / Sn / Al ₂ O ₃ (800), which has a small surface area and a low acid content, shows the optimum activity.

Claims (16)

A process for preparing an alumina support for a direct dehydrogenation reaction catalyst of n-butane, comprising the steps of:
(a) dissolving an aluminum precursor in an alcohol solvent;
(b) injecting an epoxide-based compound into the solution to obtain a gel;
(c) aging the gel at room temperature;
(d) drying the aged gel to remove the alcohol solvent; And
(e) heat treating the dried gel to obtain an alumina support for a direct dehydrogenation catalyst of n-butane having various crystalline phases. 2. The method of claim 1, further comprising adding distilled water to the aluminum precursor solution prepared in step (a) before step (b) after step (a) Gt; The method according to claim 1, wherein the alcohol solvent used in step (a) is at least one selected from the group consisting of methanol, ethanol, propanol, isopropanol, 1-butanol and 2-butanol. The method of claim 1, wherein the aluminum precursor used in step (a) is at least one selected from aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum fluoride trihydrate, aluminum phosphate hydrate and aluminum hydroxide By weight based on the total weight of the alumina support. The method of claim 1, wherein the epoxide compound used in step (b) is at least one selected from the group consisting of propylene oxide, ethylene oxide, and 1,2-epoxybutane. The method of claim 1, wherein the aging of the gel in step (c) is performed for 2 to 3 days. The method of claim 1, wherein the drying in step (d) is performed at 50 to 200 ° C for 4 to 5 days. The method of claim 1, wherein the heat treatment in step (e) is performed at a temperature ranging from 350 to 1200 ° C. The method according to claim 1, wherein the crystalline phase of the alumina support obtained in step (e) is at least one selected from gamma-alumina, theta-alumina and alpha-alumina. [3] The method of claim 2, wherein the amount of distilled water used in step (a ') is 1 to 8: 1 in terms of molar ratio of distilled water: aluminum precursor. A process for preparing a platinum catalyst comprising tin supported on an alumina support, comprising the steps of:
(i) impregnating an alumina support prepared by the method of manufacturing an alumina support according to any one of claims 1 to 10 with an aqueous tin precursor solution;
(ii) drying and heat-treating the resultant obtained in the step (i) to obtain tin supported on an alumina support;
(iii) impregnating the platinum precursor aqueous solution with the tin supported on the alumina support obtained in the step (ii); And
(iv) drying and heat-treating the resultant obtained in the step (iii) to obtain a platinum catalyst containing tin supported on an alumina support. The method according to claim 11, wherein the drying in steps (ii) and (iv) is performed at a temperature of 50-200 ° C, and the heat treatment is performed at a temperature of 400-800 ° C. ≪ / RTI > A direct dehydrogenation reaction of n-butane is carried out by using a mixed gas containing n-butane and nitrogen as a reactant on a platinum catalyst containing tin supported on an alumina support produced by the production method of claim 11, -Butene and 1,3-butadiene. 14. The process of claim 13, wherein the direct dehydrogenation of the n-butane is carried out at a temperature of 300 to 800 < 0 > C. 14. The process for producing n-butene and 1,3-butadiene according to claim 13, wherein the mixed gas has a volume ratio of n-butane: nitrogen = 1: 0.2-10. The method of claim 13, wherein the injection amount of the mixed gas is n-n, characterized in that ^1-butene and a method for producing 1,3-butadiene is the space velocity, based on the butane 10~6000 cc · hr ^-1 · gcat .

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