KR20070075064A - New supported bimetallic platinu mesoporous catalysts and their new preparation method - Google Patents

Abstract

A mesoporous type platinum-based catalyst and a method for manufacturing the same are provided to improve the activity of catalyst and the selectivity of mono olefin and reduce the amount of aromatic compound generated through sub-reaction, thereby improving the efficiency in a dehydrogenation process. A platinum-based catalyst is composed of a composite carrier and a binary metal supported on the composite carrier, wherein the binary metal has platinum as an activation component and tin as a cocatalyst. The composite carrier is formed by coating a surface of a nonporous type high-density ceramic oxide with porous type alumna having mesopores of 2 to 50 nm and a specific area surface of more than 40 m^2/g. The alumina has a weight percents of 0.5 to 10 based on the composite carrier.

Description

New Supported Bimetallic Platinu Mesoporous Catalysts and Their New Preparation Method

Figure 1 shows the adsorption isotherm of the porous alumina prepared by the sol-gel method in Example 3 of the present invention.

Figure 2 shows the adsorption isotherm and pore distribution of the porous alumina prepared using the surfactant in Example 5 of the present invention.

Figure 3 shows the adsorption isotherm of non-porous alumina in Comparative Example 1 of the present invention.

The present invention relates to a novel mesoporous platinum-based catalyst and a method for preparing the same, and more particularly, a mesoporous sized porous alumina coated with a non-porous, high density ceramic oxide surface having a specific surface area of 40 m ² / g or more. After the carrier is supported on the binary metal complex compound of platinum and tin, and the hydrocarbon conversion process is carried out using a mesoporous platinum catalyst prepared by microwave irradiation, the conversion rate is improved without deactivation due to the conventional acid point. The present invention relates to a novel mesoporous platinum-based catalyst which can be usefully used in the petrochemical industry by improving the selectivity of mono-olefins and suppressing the production of aromatic compounds as side reactions, and a method for preparing the same.

Hydrogenation, catalytic cracking, catalytic reforming and dehydrogenation are very important petrochemical reactions.

Typical applications of the dehydrogenation reaction process used in the petrochemical industry include processes for producing aliphatic olefins such as propylene, iso-butene, straight chain mono-olefins in the range of C ₁₀ to C ₁₅ , and unsaturated such as styrene monomers. It can be divided into manufacturing processes of aromatic compounds. Aliphatic mono-olefins produced from aliphatic paraffins are used as raw materials for plasticizers, biodegradable detergents (LAS), detergent alcohols, ethoxylates, etc., depending on molecular weight.

The dehydrogenation process is seemingly simple, but if you look closely it is one of the most complex processes. In general, dehydrogenation is a thermodynamically limiting reaction. In particular, it requires a lot of heat because the conversion is limited and the endothermic reaction is very high. When the temperature is increased to increase the conversion, decomposition, isomerization, aromatization, and small polymerization reaction are required. Complex side reactions such as In addition, the biggest problem is the deactivation of the catalyst by the formation of coke. When an aromatic compound having a high molecular weight that becomes a precursor of coke is produced, the catalyst is irreversibly adsorbed onto the surface of the catalyst to deactivate the catalyst, It is possible to remove the coke from the catalyst surface only by washing with water. From the thermodynamic point of view, the CC bond energy is 245 kJ / mol, which is less than the CH bond energy of 365 kJ / mol. The selection of catalysts and reaction conditions that can effectively occur is very important. Thus, dehydrogenation catalysis must be carried out at relatively low temperatures in order to inhibit pyrolysis reactions, and appropriate mono-olefin selectivity and conversion rates are needed to suppress by-product formation and match process economics.

Various dehydrogenation processes have been applied industrially to prepare mono-olefin compounds. In general, platinum is used as an active ingredient, and tin (Sn), cobalt (Co), lead (Pb), One component of indium (In), germanium (Ge) and cesium (Ce) is used and at least one of alkali metal and alkaline earth metal is used as an additive to suppress side reactions due to acidity of the catalyst.

Looking at the main reactants that can be produced in the process of producing a linear mono-olefin (n-monoolefin) by the dehydrogenation of the linear paraffin (n-paraffin) as follows.

As indicated above, to obtain only linear mono-olefins selectively requires a very selective dehydrogenation catalyst, and the conversion is determined by the temperature, pressure, and molar ratio of the reactant hydrogen / linear paraffins. Increases, and decreases with higher pressure and hydrogen / linear paraffin ratio. In addition, the optimum yield can be obtained as a function of space velocity.The higher the space velocity, the lower the conversion rate due to failure to equilibrium, and the lower the space velocity, the lower the selectivity of the linear mono-olefin due to side reactions. Speed exists. Generally, dehydrogenation conditions of linear paraffin used are reaction temperature of 450 ~ 500 ℃, pressure of 1 ~ 2 atm, space velocity (LHSV) 10 ~ 20 h ^-1 , hydrogen to hydrocarbon molar ratio of 3 ~ 9, The hydrocarbon conversion obtained at this time is 10 to 18%, the mono-olefin selectivity is obtained about 80 to 95%.

The representative platinum-based supported catalysts used in the linear paraffin dehydrogenation reaction are platinum (Pt) -tin (Sn) -lithium (Li) catalysts supported on gamma-alumina. The active ingredient is highly dispersed platinum but does not play a role in tin. It is known to be very important for activity, selectivity, and catalyst stability (US Pat. No. 4973779).

Gamma-alumina carriers are known as optimum carriers for stabilizing the dispersion of platinum in dehydrogenation catalysts. Factors that reduce the stability of the catalyst include the generation of carbon deposits, that is, the contact area between the active surface and the reactant by reducing the contact efficiency between the active site microsurface and the reactant by caulking and sintering between the reaction or subsequent active ingredients. Caused by a decrease or the like. The role of tin in the platinum (Pt) -tin (Sn) catalyst is that tin-modified platinum-based catalysts can be highly dispersed on the surface of the carrier with small platinum particles by the addition of tin, and the activity of platinum is greatly changed to make coke precursors. Is known to block adsorption on the platinum surface and to move the coke precursor onto the carrier, which in turn prevents the deactivation of the active site. In addition, since the acid point of the catalyst in the dehydrogenation catalyst promotes the hydrocracking reaction of the CC bonds of the straight-chain paraffins, degrading the selectivity of the catalyst and causing catalyst deactivation, alkali metals such as lithium are often added to neutralize the acid point of the carrier. do.

On the other hand, looking at the prior art of the catalyst of the linear paraffin dehydrogenation reaction has been focused mainly on three aspects so far. First, an efficient method for producing carrier particles that can be utilized for high dispersion of platinum and promoter, and second, a high dispersion method of platinum and promoter for enhancing activity and selectivity of dehydrogenation catalyst, and third, to inhibit dehydrogenation catalyst deactivation. There are three methods for producing a catalyst that can be used.

First, spherical alumina carriers are widely used as platinum-based dehydrogenation catalyst carriers. In the case of linear paraffin dehydrogenation reactions, in order to increase the high dispersion of the catalytically active component and the applicability to the dehydrogenation process, it is generally 0.5 g / mL or less. Properties of alumina carriers having low density, high surface area of 100 m 2 / g or more, large pore size and high pore volume are required (US Pat. Nos. 2,620,314, 5,358,920).

In order to increase the conversion and selectivity of the reaction of the dehydrogenation catalyst of saturated hydrocarbons, U.S. Patent No. 4,608,360 used a method of supporting the catalyst components by continuous impregnation in porous gamma alumina having a large surface area and a large pore volume. . U.S. Patent No. 4,914,075 exemplifies a method of supporting and preparing an alkali or earth metal which is a promoter to weaken the acidic point of gamma-alumina for coke formation mitigation in a Pt-Sn / Al ₂ O ₃ catalyst. And, U.S. Patent No. 3,531,543, 1 - 3,725,304 arc, in the 4,070,403 Ho, C ₂ ~ a dehydrogenation catalyst component of the paraffin hydrocarbon of C ₃₀ range platinum (Pt), tin (Sn), a lithium, and a support of gamma-alumina ( γ-Al ₂ O ₃ ) has been reported.

In addition, U.S. Patent Nos. 3,998,900, 4,430,517, 4,608,360 and 4,677,237 disclose platinum, which is an active ingredient as a dehydrogenation catalyst, tin (Sn) or indium (In) as a promoter, and lithium (Li) or potassium ( K) is used as an additive to lower the acidity of the carrier. In many cases, uniform impregnation has been proposed to induce relatively uniform distribution of platinum and tin or cocatalyst components on and within spherical gamma-alumina as a general method for preparing a platinum-based catalyst.

However, surface impregnation is used instead of the uniform impregnation method, which is a conventional method for preparing a platinum-based catalyst, to prevent specific side reactions from being promoted due to excessive exposure of reactants or products at the catalyst active point, thereby decreasing olefin selectivity. Platinum based catalysts have been proposed. For example, US Pat. No. 4,716,143 describes a catalyst wherein a platinum group metal is supported within 400 μm of the gamma-alumina carrier surface and similarly US Pat. No. 4,786,625 describes that platinum is present on the surface of the carrier and the promoter component is the entire carrier. Although a uniformly distributed catalyst was proposed in this case, even in this case, since the tin component is distributed throughout the surface and the inside of the carrier, extra tin should be added in addition to the tin component used for the cocatalyst action with platinum.

In addition, a catalyst or a method for preparing a catalyst in which a catalyst active ingredient is supported on a two-layer carrier having different compositions or properties of an inner core and an outer layer or shell has been proposed for a long time. Patents have reported that platinum based catalysts using this type of carrier show good catalytic activity and stability in hydrocarbon dehydrogenation processes. For example, in US Pat. No. 6,177,381 B1, platinum and phosphorus are applied to the surface of a two-layered carrier in which a material such as alpha-alumina is used as a carrier internal material and a coating of a refractory inorganic oxide such as gamma-alumina is sprayed onto the surface. It has been reported that a uniformly dispersed tin and lithium catalyst improves the selectivity of the hydrocarbon dehydrogenation reaction and the durability of the catalyst. A polyvinyl alcohol, an organic binder, is used to bind alpha-alumina and gamma-alumina. A method of improving the wear of the catalyst is described.

In US Pat. No. 6,280,608 B1, hydrocarbon conversion processes such as hydrogenation, dehydrogenation, and oxidation of hydrocarbons using catalysts obtained in US Pat. No. 6,177,381 B1, US Pat. No. 6,486,370 B1 disclose hydrocarbons in dehydrogenation conditions with low water content. Has presented a dehydrogenation process.

Accordingly, the present inventors endeavor to develop a new hydrocarbon conversion process catalyst and method for producing a catalyst in which the catalyst due to the acid point formation of the conventional porous oxide carrier is deactivated and the heterogeneous distribution of active ingredients is improved. It was. As a result, a porous carrier having a specific mesoporous range is coated on the surface of the non-porous high density ceramic oxide with a carrier, and the composite carrier having a low acid point is supported on a binary metal complex of platinum as an active ingredient and tin as a promoter. By preparing a platinum-based catalyst, it was found that the active ingredient and the cocatalyst are uniformly distributed so that the activity is not significantly reduced even at a low content, thereby completing the present invention.

It is therefore an object of the present invention to provide a novel catalyst for platinum-based hydrocarbon conversion, which exhibits high selectivity in the dehydrogenation reaction while reducing the production of side reactants at high conversion rates without degrading activity.

It is another object of the present invention to provide a method for preparing the novel mesoporous platinum-based hydrocarbon conversion process which induces efficient dispersion of an active ingredient and a promoter by using microwaves during drying.

The present invention provides a composite carrier comprising a porous alumina of mesoporous size having a specific surface area of 40 m ² / g or more on a non-porous high density ceramic oxide surface,

The catalyst is characterized by a platinum-based hydrocarbon conversion process carrying a binary metal of platinum as an active ingredient and tin as a promoter.

In addition, the present invention is a mixed solution containing 90 to 100% by weight of alumina sol, 0 to 10% by weight of zirconia sol or titania sol, 0.5 to 10 parts by weight of organic acid and 0.1 to 5 parts of water-soluble polymer with respect to 100 parts by weight of the mixed solution. 1 step of preparing a composite carrier by coating the alumina mixed solution containing parts by weight on the surface of the high-density ceramic oxide;

To 100 parts by weight of the one-step composite carrier, 0.1 to 10 parts by weight of platinum chloride dissolved in alcohol, 0.1 to 20 parts by weight of tin chloride and 1 to 10 parts by weight of inorganic acid were added, followed by reaction at a temperature of 25 to 80 ° C. Forming a platinum-tin complex solution; And

Three steps of heat treatment by irradiating microwaves for 30 seconds to 10 minutes in a power range of 100 to 1500 W by supporting a complex carrier of one step in the platinum-tin complex solution of two steps;

There is another feature in the method for producing a catalyst for a platinum-based hydrocarbon conversion process comprising a.

Hereinafter, the present invention will be described in detail.

The present invention provides a novel mesoporous platinum-based hydrocarbon conversion process catalyst having a high selectivity for linear paraffin hydrocarbons while improving the conversion rate during the dehydrogenation reaction of hydrocarbons and inhibiting side reactions, and a method for preparing the same and a hydrocarbon conversion process using the same. It is about.

First, the novel platinum-based catalyst according to the present invention will be described in more detail as follows.

The catalyst of the present invention is a non-porous, high-density ceramic oxide surface, platinum and cocatalyst as active ingredients in a composite carrier coated with porous alumina adjusted to have a mesopore size of 2 to 50 nm and a specific surface area of 40 m ² / g or more. The biggest feature of the technical construction is that the tin, which is a component, is supported on microwave irradiation conditions.

Conventionally, alumina, a porous oxide having a high surface area, has been used as a carrier for the purpose of maximizing dispersion of the active ingredient and the promoter, but the surface acid point of the carrier acted as a cause of deactivation of the catalyst including coke formation. . In order to prevent such a problem, a small amount of alkali metal or earth metal was added to neutralize the acid point or gelation of tin and alumina simultaneously to prepare an alumina carrier having evenly distributed tin. However, since the above method cannot remove the acid point fundamentally, there is a limit in suppressing side reactions such as aromatic compounds when the hydrocarbon is dehydrogenated using the catalyst.

In addition, low surface area, high density oxide carriers can avoid the deactivation of the catalyst due to acidity, but there is another problem that greatly reduces the dispersion of the active ingredient and the promoter component, which is almost not useful.

The present invention recognizes the importance of the selective use of such a carrier and has conducted a thorough study on it. As a result, a non-porous, high density ceramic oxide is used as the core and its surface has a mesopore of 2 to 50 nm and 40 m ² / g or more. When forming a cell structure coated with porous alumina adjusted to have a specific surface area, no problem occurs due to acid point by the high-density ceramic oxide, and the porous alumina is coated and contained in a certain component ratio to form active ingredients and promoters. The degree of dispersion can be improved. In other words, the monoolefin is made by forming a porous alumina having uniform mesopores controlled to a specific range rather than a simple mixed form combining a non-porous high-density ceramic oxide and a porous alumina as a conventional carrier to facilitate the movement of the reactant hydrocarbon. It is possible to obtain an effect of suppressing side reactions due to high selectivity and coke formation. In the case of simply mixing, the problem of coke generation due to acid point and accessibility of the reactants due to nonuniformity of mesopore of gamma alumina occurs, so that the effect of the present invention cannot be obtained. It is possible only if the surface of the core forms a structure coated with a uniform mesopore of 2 to 50 nm and a porous cell adjusted to have a specific surface area of 40 m ² / g or more.

The non-porous high-density ceramic oxide is generally used in the art, but is not particularly limited. Specifically, for example, alumina containing magnesium, magnesium and calcium aluminate spinel oxide containing alumina, mullite, It is preferred to use yttrium stabilized zirconia (YSZ), calcium stabilized zirconia (CSZ), alumina and cordierite. More preferably, it is preferable to use alumina containing magnesium, and the magnesium preferably contains 5% by weight or less. When the content of magnesium exceeds 5% by weight, a problem arises in that the mechanical strength of the spherical high density carrier is weakened. Therefore, it is preferable to use alumina containing magnesium in the above range.

The porous alumina is contained in 0.5 ~ 10% by weight of the composite carrier, if the content is less than 0.5% by weight, the problem of thermal stability during the filling period of the catalyst, if the content exceeds 10% by weight the active catalyst layer is thick Problem occurs that leads to a decrease in reactivity. In addition, in the composite carrier in which at least one transition metal such as zirconia and titania is substituted in addition to the alumina, the alumina is mixed in a molar ratio of 0.05 to 5: 99.95 to 95 with respect to the transition metal, and the content is in a range to solve the problem of acid point of alumina. More preferably 0.05 to 1: 99.95 to 99 molar ratio.

The porous alumina preferably has a meso size, preferably 2 to 50 nm of pores, and if the pore size is less than 2 nm, problems occur in the movement of the reactants. It is desirable to maintain the above range because there is a problem that it is difficult to expect the effect of the adjustment. In addition, it is preferable that the specific surface area of the porous alumina has a value of at least 40 m ² / g or more, and when the specific surface area is 40 m ² / g or less, a problem that high dispersion effect of the supported metal by mesoporous may not be obtained.

The coating solution of the alumina is mixed with 90 to 100% by weight of alumina sol, 0 to 10% by weight of zirconia or titania sol, and mixed with an organic acid and a water-soluble polymer to facilitate easy adhesion to a high density ceramic carrier. For example, citric acid, tartaric acid, and oleic acid may be selected as the organic acid, and 0.5 to 10 parts by weight may be used based on 100 parts by weight of the alumina solution. In addition, the water-soluble polymer may be used methyl cellulose or ethylene glycol, it is preferable to use 0.1 to 5 parts by weight based on 100 parts by weight of the alumina solution.

The organic acid and the water-soluble polymer are not essential components but are additionally added to express the above effects. When the organic acid and the water-soluble polymer are out of the above range, the content of the alumina component, which is a relatively essential component, is lowered, so it is preferable to maintain the range.

In addition, in order to control uniform mesopores of the alumina composite carrier, a surfactant is added to the coating solution. The surfactant may be selected from ionic surfactants, amphoteric polymer surfactants, and Pluronic. The ionic surfactant is C _n H _{2n +1} N (CH ₃ ) 3X and C _n H _{2n +1} N (C ₂ H ₅ ) 3X series (where n = an integer from 8 to 22, X = Cl, Br And halogen atoms such as I or F), and amphoteric polymer surfactants are C _n H _{2n + 1} (OCH ₂ CH ₂ ) _x OH series (wherein n is an integer from 12 to 23, and an integer is x = 0 to 100). , Pluronic (EO) x (PO) y (EO) x series (20 <x <120, 20 <y <120) can be used, these surfactants are 100 parts by weight of the coating solution 1 to 10 parts by weight relative to the use. If the amount of the surfactant is less than 1 part by weight, the amount is too small to exhibit the desired effect, and if the amount exceeds 10% by weight, the problem of uniformity occurs during coating due to the rapid increase in viscosity, thereby maintaining the above range. Good to do.

The coating solution prepared as described above is coated with a thickness of 20 to 500 μm on the surface of the high density ceramic oxide after firing. If the thickness is less than 20 μm, there is a problem of thermal stability during the reaction. Problems with diffusion of reactants occur.

The composite carrier prepared above was supported on a complex compound solution containing platinum as an active ingredient and tin as a cocatalyst component in a predetermined ratio to prepare a mesoporous platinum-based catalyst.

The method of supporting the carrier is not particularly limited to that used in the preparation of a catalyst used in the art, and the present invention uses an impregnation method.

The platinum and tin are derived from precursor compounds such as chlorides, nitrides, sulfides, and carbides, but are not particularly limited. Preferably, chloride and tin are used, and these platinum and tin are preferably contained in a molar ratio of 1: 0.5 to 3.0. . If the molar ratio of tin is less than 0.5 molar ratio, it is difficult to form an alloy of platinum and tin, and there is a high possibility of coke formation, and when the molar ratio exceeds 3.0, coke generation can be suppressed, but a problem of inactivation is caused by a large amount of tin. Therefore, it is good to maintain the above range. At this time, platinum as an active metal is contained in the composite carrier 0.03 to 5% by weight, the activity is significantly reduced when the content is less than 0.03% by weight, when the content exceeds 5% by weight there is a problem that there is no economic efficiency.

To 100 parts by weight of the composite carrier, 0.1 to 10 parts by weight of platinum chloride dissolved in alcohol, 0.1 to 20 parts by weight of tin chloride and 1 to 20 parts by weight of inorganic acid are added, followed by reaction to form a platinum-tin complex solution. .

As the inorganic acid used to form the complex compound of platinum and tin, for example, sulfuric acid, nitric acid and hydrochloric acid may be used, and hydrochloric acid is used in the present invention. When the amount of the hydrochloric acid used is less than 1 part by weight or more than 10 parts by weight, the formation of a complex does not occur, so it is preferable to inject an appropriate amount within the above range.

Conventional alcohols such as methanol, ethanol and isopropanol may be used as reaction solvents in the preparation of the platinum-tin complex solution, and in the preparation of the complex solution, it is preferable to use a glass reactor because of the reactivity by acid. In addition, since the reaction temperature is maintained at 25 to 80 ° C., when the reaction temperature is out of the reaction temperature, a preferable Pt-Sn complex compound is not formed.

The composite carrier is supported on the platinum-tin complex solution prepared above, wherein the supporting temperature is maintained at 25 to 60 ° C. Thereafter, the catalyst precursor solution carrying the composite carrier was evaporated in an oil bath at a vacuum of 100 mmHg or less and a temperature of 40 to 80 ° C. using a vacuum evaporator (Rotary Evaporator, Model 4000). To obtain a sample in which the Pt-Sn precursor is supported on the surface of the composite carrier. However, the Pt-Sn precursor on the surface of the dried composite carrier in a vacuum evaporator is co-ordinated with water and alcohol, which requires an additional drying process. It was observed that the uniform dispersion of the catalyst components is not easy due to the rapid concentration deviation of the solvent, and further, the catalyst activity and the selectivity decrease greatly due to the uneven distribution of platinum and tin.

Thus, in the present invention, using a microwave dryer capable of power control in the range of 100 ~ 1500 W by irradiating microwaves in the range of 30 seconds to 10 minutes according to the amount of the sample of the Pt-Sn precursor is carried on the surface of the composite carrier Induces uniform dispersion of platinum-tin components. If the microwave power range is less than 100 W, the drying effect is insignificant, and if it exceeds 1500 W, there is a problem of low energy efficiency, and if the irradiation time is less than 30 seconds and there is no sufficient drying effect, and exceeds 10 minutes Sintering problems between Pt-Sn precursors occur.

In addition, the microwave dryer may blow hot air in the range of 100 mL to 10 L per minute during microwave heating, and attach a discharger to discharge the hydrochloric acid gas generated during heating out of the microwave dryer to prevent surface adsorption of hydrochloric acid gas. When the chlorine concentration remaining after the catalyst treatment in the microwave dryer was measured, the concentration was found to be within 0.2% based on the weight of the catalyst. When passing air through the hot air during microwave heating, the catalyst drying as well as the catalytic baking effect were obtained. As a result, no further firing was necessary.

The catalyst obtained by the above method is reduced to hydrogen for 2 to 6 hours at 500 ~ 650 ℃ and finally a platinum-based catalyst supported on a binary metal is prepared.

The acidity of the surface of the novel dehydrogenated platinum catalyst prepared by the above method is significantly lower than that of the conventional dehydrogenated catalyst using a high surface area porous carrier, so that there is no need to add an alkali metal as in the prior art to neutralize the surface acid point. do.

On the other hand, the platinum-based catalyst prepared above can be applied to the selective paraffin dehydrogenation reaction. The dehydrogenation reaction is not particularly limited to a process commonly used in the art, for example, in the present invention, the reaction is carried out under conditions such as a dehydrogenation reaction apparatus, a reaction condition, and a method for measuring catalytic activity.

First, the apparatus used in the present invention is a typical fixed bed catalyst reactor manufactured directly in the laboratory. In a 3/8 inch stainless steel reactor, a stainless steel filter having a pore size of 1 μm was welded and fixed in the middle of the reactor to prevent the catalyst powder from sinking to the bottom of the reactor during the reaction, followed by a reduced platinum based catalyst thereon. Fill 3 to 15 mL. Liquid hydrocarbon reactants are quantitatively injected into the reactor using an HPLC pump (ICI LC 1110) and hydrogen gas is introduced using a mass flow controller to suppress catalyst deactivation. Dehydrogenation conditions of the linear paraffin were set in the range of reaction temperature of 400 ~ 500 ℃, pressure of 0.5 ~ 5 atm, space velocity LHSV = 1 ~ 20 h ^-1 , hydrogen to hydrocarbon mole ratio = 3 ~ 9. At this time, the aliphatic hydrocarbon mixture is composed of C ₁₀ to C ₁₆ straight chain hydrocarbon. The composition of the hydrocarbon before and after the reaction was analyzed using HPLC with a refractive index detector. In this case, two silica HPLC columns were connected in series, and the elution solvent of HPLC used iso-octane hydrocarbon. use.

The reaction was carried out under conditions similar to those of the prior art. When the novel platinum-based catalyst of the present invention was used, catalytic activity and monoolefin selectivity were improved, and the amount of aromatic compounds produced by the side reaction was reduced to half. Seems.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Example 1 Preparation of Ceramic Carrier

76% by weight of gamma-alumina powder was mixed with 1.6% by weight of bentonite (Junsei, Japan), 2.4% by weight of methyl cellulose and 20% by weight of distilled water, and then a size of 1.5-2.0 mm in diameter using a rotary granulator. The spherical carrier of was molded and dried at 120 ° C. for 5 hours, and then calcined at 1100 ° C. for 12 hours to prepare an oxide carrier.

The spherical carrier prepared above was pretreated in 1 N dilute nitric acid solution at 70 ° C. for 1 hour, and then sufficiently washed with little distillate with distilled water and dried at 120 ° C. for 12 hours to form an activated oxide surface.

Example 2 Preparation of Ceramic Carrier

76% by weight of yttrium stabilized zirconia (YSZ) powder was mixed with 1.6% by weight of bentonite (Junsei, Japan), 2.4% by weight of methyl cellulose and 20% by weight of distilled water, and then a diameter was formed using a rotary spherical ceramic granulator. A spherical carrier having a size of 1.5 to 2.0 mm was molded, dried at 120 ° C. for 5 hours, and calcined at 1100 ° C. for 12 hours to prepare an oxide carrier.

The spherical carrier prepared above was pretreated in 1 N dilute nitric acid solution at 70 ° C. for 1 hour, and then sufficiently washed with little distillate with distilled water and dried at 120 ° C. for 12 hours to form an activated oxide surface.

Example 3 Porous Alumina Supported Platinum-Based Catalyst (Catalyst A)

54.11 g of aluminum isopropoxide was placed in a 500 mL beaker containing 200 g of isopropyl alcohol solvent and mixed with stirring at room temperature. In another beaker, 4.74 g Citric acid and 3.5 g ethylene glycol were completely dissolved in a solution containing 24 g distilled water and 13 g concentrated hydrochloric acid solution. After mixing the two solutions, and stirred for 3 hours at 80 ℃ to prepare an aluminum coating solution.

Thereafter, the aluminum solution prepared above was added to the alumina oxide having a weight of 10% by weight on the spherical magnesium alumina oxide carrier obtained in Example 1, and then stirred in a vibratory shaker for 3 hours and then vacuum evaporated at 80 ° C. . Next, an alumina / magnesium aluminate composite carrier was prepared by drying at 120 ° C. for 5 hours and firing at 600 ° C. for 6 hours.

Next Figure 1 shows the BET isothermal adsorption and desorption graph of the powder formed using the coating solution prepared above, it was confirmed that the porous nanopores. BET analysis of the prepared catalyst confirmed that the average specific surface area was 108 m ² / g.

In the alumina / magnesium aluminate composite carrier prepared above, a catalyst (catalyst A) containing platinum as an active ingredient and tin as a cocatalyst was prepared by the following method. At this time, a platinum-tin complex compound called red trans-PtCl ₂ (SnCl ₃ ) ₂ was used in the preparation of the catalyst as a compound containing the active ingredient of platinum and tin at the same time.

The complex compound was first mixed with 0.223 g of platinum salt (H ₂ PtCl ₆ .xH ₂ O) and 0.194 g of dibasic dichloride (SnCl ₂ · 2H ₂ O) in a 50 mL ethanol solvent, followed by 300 mL of 1N aqueous hydrochloric acid solution. Prepared by addition.

To the platinum-tin complex solution prepared above, 50 g of a composite carrier dried at 120 ° C. was added thereto, stirred for 3 hours in a shaker, and evaporated in vacuo at 80 ° C. Then, the catalyst was transferred to a microwave dryer equipped with a hot air blower and an ejector, the microwave power was adjusted to 1200 W, the microwave was irradiated for 5 minutes, and the platinum-based catalyst was dried and calcined.

When the content of the platinum-based catalyst obtained above was investigated through elemental analysis of inductively coupled plasma (ICP), it was confirmed that 0.16% by weight of platinum and 0.21% by weight of tin were contained.

Example 4 Porous Zirconium-Alumina Supported Platinum-Based Catalyst (Catalyst B)

52.31 g of aluminum isopropoxide and 2.037 g of zirconium oxychlorine compound (ZrOCl ₂ · 8H ₂ O) were added to a 500 mL beaker containing 200 g of isopropyl alcohol solvent and mixed at room temperature with stirring. In another beaker, 4.74 g Citric acid and 3.5 g ethylene glycol were completely dissolved in a solution containing 24 g distilled water and 13 g concentrated hydrochloric acid solution. After the two solutions were mixed, the mixture was stirred at 80 ° C. for 3 hours to prepare a zirconium-aluminum (Al: Zr = 95: 5 molar ratio) coating solution.

Thereafter, the zirconium-aluminum solution prepared above was added to the zirconium-alumina oxide having a weight of 10% by weight on the spherical magnesium aluminate oxide carrier obtained in Example 1, followed by stirring for 3 hours in a vibratory shaker. Vacuum evaporated at ° C. Next, a zirconium-alumina / magnesium aluminate composite carrier was prepared by drying at 120 ° C. for 5 hours and firing at 600 ° C. for 6 hours. It was confirmed that the average specific surface area of the powder formed using the prepared coating solution was 103 m ² / g.

In the zirconium-alumina / magnesium aluminate composite carrier prepared above, a catalyst (catalyst B) containing platinum as an active ingredient and tin as a promoter was prepared by the following method. At this time, a platinum-tin complex compound called red trans-PtCl ₂ (SnCl ₃ ) ₂ was used in the preparation of the catalyst as a compound containing the active ingredient of platinum and tin at the same time.

The complex compound was first mixed with 0.223 g of platinum salt (H ₂ PtCl ₆ .xH ₂ O) and 0.194 g of dibasic dichloride (SnCl ₂ · 2H ₂ O) in a 50 mL ethanol solvent, followed by 300 mL of 1N aqueous hydrochloric acid solution. Prepared by addition.

To the platinum-tin complex solution prepared above, 50 g of a composite carrier dried at 120 ° C. was added thereto, stirred for 3 hours in a shaker, and evaporated in vacuo at 80 ° C. Then, the catalyst was transferred to a microwave dryer equipped with a hot air blower and an ejector, the microwave power was adjusted to 1200 W, the microwave was irradiated for 5 minutes, and the platinum-based catalyst was dried and calcined.

When the content of the platinum-based catalyst obtained above was investigated through elemental analysis of inductively coupled plasma (ICP), it was confirmed that 0.16% by weight of platinum and 0.20% by weight of tin were contained.

Example 5 Porous Alumina Supported Platinum Catalyst Using Catalyst (Catalyst C)

A mesoporous alumina carrier was prepared by further using a neutral polymer surfactant on the surface of the ceramic composite support of Example 1.

A mixed solution of 40.65 g of aluminum isopropoxide, 50 g of isopropyl alcohol and 30 g of concentrated hydrochloric acid (containing 37% by weight HCl) was placed in a 250 mL round flask reactor equipped with a reflux condenser and 5 at 85 ° C. After mixing for time, the mixture was cooled to room temperature. 10 g of a polymer surfactant (BASF trade name, Pluronic F127; (EO) 106 (PO) 70 (EO) 106) and 5 g of additives (Aldrich, PPO; Poly (propylene oxide)) in the above-cooled mixed solution ) Was added, followed by stirring at room temperature for 2 hours to prepare a sol solution.

The spherical magnesium aluminate oxide carrier of Example 1 was coated with 7 wt% of the aluminum mixed solution prepared above, followed by drying at room temperature for 2 hours and then at 120 ° C. for 5 hours. Thereafter, the coated carrier was calcined at 600 ° C. for 6 hours to prepare an alumina / magnesium aluminate composite carrier.

At this time, in the manufacturing process of the composite carrier, the spherical carrier was filtered and some of the powder remaining in the solution was filtered, dried at 120 ° C. for 5 hours, and calcined at 600 ° C. for 6 hours. As shown in FIG. 2, the composite carrier prepared above had three tool baths of 10 nm, and it was confirmed that an alumina oxide having a mesoporous structure having a surface area of 280 m 2 / g was synthesized.

In the same manner as in Example 3, a platinum-based catalyst (catalyst C) containing 0.16% by weight of platinum as an active ingredient and 0.20% by weight of tin as a promoter was prepared in the composite carrier prepared using the surfactant.

Example 6 Porous Alumina Supported Platinum-Based Catalyst (Catalyst D)

In the same manner as in Example 3, but instead of aluminum isopropoxide, which is a precursor solution of aluminum in the alumina mixed solution, containing 5% by weight of alumina precursor of boehmite (AlOOH) series and 1N concentration of acetic acid A composite carrier was prepared by coating the surface of the yttrium stabilized zirconia (YSZ) oxide carrier obtained in Example 2 using an alumina sol solution.

Thereafter, a platinum-based catalyst (catalyst D) containing 0.16% by weight of platinum as an active ingredient and 0.20% by weight of tin as a promoter was prepared in the composite carrier prepared above.

Comparative Example 1 A non-porous alumina supported platinum catalyst (catalyst E)

A catalyst was prepared in the same manner as in Example 5 except that no surfactant was used in the alumina mixed solution. A platinum-based catalyst (catalyst E) containing 0.16% by weight of platinum as an active ingredient and 0.20% by weight of tin as a cocatalyst was prepared in the prepared composite carrier. Next, Figure 3 shows the BET isothermal adsorption and desorption graph of the powder formed using the coating solution prepared above, it was confirmed that the non-porous material having only macropores. BET analysis of the prepared surface catalyst layer was an average of 30 m ² / g.

Comparative Example 2 Pt-Sn-Li / ZrO ₂ -Al ₂ O ₃ / a-Al ₂ O ₃ (Catalyst F) Prepared by General Drying Method

As the carrier, a spherical alpha alumina carrier having a bulk density of 0.70 g / mL on which a gamma alumina was supported was used. To coat Al ₂ O ₃ with 0.165 wt% platinum and 0.20 wt% tin (molar ratio: Sn / Pt = 2), the supported solution was added with 0.223 g of platinum salt (H ₂ PtCl ₆ .xH ₂ O) and 0.194. g of dibasic citrate (SnCl ₂ · 2H ₂ O) was mixed in 50 mL ethanol and 300 mL of 1N hydrochloric acid was added. A platinum-tin-containing alumina catalyst was prepared by carrying 50 g of alumina carrier dried in an oven at 120 ° C. in a supported solution, vacuum evaporating at 80 ° C., drying at 120 ° C. for 12 hours, and calcining at 550 ° C. for 3 hours.

Comparative Example 3 Pt-Sn-Li / r-Al ₂ O ₃ Prepared by a General Drying Method (Catalyst G)

The carrier was prepared in a similar manner to Example 3 of US Pat. No. 4,677,237 in a solution containing 0.531 g of platinum salt (H ₂ PtCl ₆ .xH ₂ O) and 3.974 g of LiNO ₃ , 1 N nitric acid (HCl) in 300 mL. It is mixed with spherical 50 g tin-alumina (SnO ₂ / γ-Al ₂ O ₃ ) having a bulk density of 0.46 g / mL, vacuum evaporated at 40 ° C., dried at 120 ° C. for 12 hours, and then 3 hours at 550 ° C. Firing was carried out to prepare a platinum-tin-containing alumina catalyst. At this time, the composition of the catalyst G prepared above showed 0.38 wt% Pt, 0.495 wt% Sn, 0.58 wt% Li.

[Comparative Example 4] Dehydrogenation catalyst (catalyst H) of double layer structure

A dehydrogenation catalyst is prepared by coating platinum, tin, and lithium on a gamma alumina / gamma alumina layered structure by a method similar to that shown in Example 2 of US Pat. No. 6,1777,381. At this time, the composition of the catalyst H prepared above showed 0.10 wt% Pt, 0.10 wt% Sn, 0.25 wt% Li.

Experimental Example Dehydrogenation Experiment

In Examples 3 to 6 and Comparative Examples 1 to 4, the dehydrogenation activity and selectivity of the linear hydrocarbons were measured in a fixed bed catalyst reactor.

Each of the catalysts were charged in a 3/8 inch stainless steel tubular reactor, each 5 mL, and heated at a rate of 5 ° C. per minute from room temperature to 500 ° C. while flowing hydrogen at 300 mL, and reduced at 500 ° C. for 2 hours. After treatment, a paraffin dehydrogenation reaction was performed according to the reaction conditions. The product solution passed through the reactor was collected by cooling to a temperature of 4 ℃ or less, the solution after the reaction was analyzed for concentration using HPLC to confirm the activity and selectivity of the catalyst.

At this time, the linear hydrocarbon used was 11.8% by weight of C ₁₀ hydrocarbon, 34.7% by weight of C ₁₁ hydrocarbon, 30.5% by weight of C ₁₂ hydrocarbon, 19.9% by weight of C ₁₃ hydrocarbon, and 0.27% by weight of C ₁₄ hydrocarbon. In addition, the dehydrogenation reaction conditions are shown in the following Table 1 reaction results obtained under the conditions of 1 atm, 460 ℃, LHSV = 20 / h, hydrogen to hydrocarbon mole ratio = 4.5.

TABLE 1

As shown in Table 1 above, when the dehydrogenation reaction was carried out using the platinum-based catalysts of Examples 3 to 6 fired using a composite carrier according to the present invention and fired using microwaves, the activity prepared by a conventionally presented method. It was confirmed that the selectivity of the olefin was improved as compared with the catalysts of Comparative Examples 2 to 4 having a high content of platinum as a component, and the yield of the aromatic compound as a side reactant tended to decrease to 50% or less. In particular, the porous catalysts of Examples 3 to 6 (A, B, C and D), which have a large specific surface area compared to the non-porous catalyst D of Comparative Example 1 (A, B, C and D), have been greatly improved by the uniform dispersion of active ingredients Pt and Sn in a large specific surface area. Conversion and olefin selectivity are shown.

As described above, according to the present invention, a composite carrier comprising a mesoporous sized porous alumina having a specific surface area of 2 to 50 nm mesopores and at least 40 m ² / g is coated on a nonporous high density ceramic oxide surface. The prepared platinum-based catalyst is prepared by microwave irradiation, which improves catalytic activity and monoolefin selectivity, and reduces the amount of aromatic compounds produced by side reactions to about half, thereby greatly improving the efficiency of the representative dehydrogenation process of the petrochemical industry. It works.

Claims (15)

In a composite carrier comprising a mesoporous-sized porous alumina coated with a non-porous high density ceramic oxide surface having pores of 2 to 50 nm meso size and a specific surface area of 40 m ² / g or more, A catalyst for a platinum-based hydrocarbon conversion process, characterized in that a binary metal of platinum as an active ingredient and tin as a promoter is supported. The method of claim 1, The alumina is a platinum-based hydrocarbon conversion process catalyst, characterized in that contained 0.5 to 10% by weight of the composite carrier. The method of claim 1, A catalyst for a platinum-based hydrocarbon conversion process, characterized in that the composite carrier is substituted with one or more transition metals such as zirconia and titina in addition to the alumina. The method of claim 3, wherein Alumina relative to the substituted transition metal is a catalyst for a platinum-based hydrocarbon conversion process, characterized in that contained in a molar ratio of 0.05 to 5: 99.95 to 95. The method of claim 4, wherein Alumina relative to the substituted transition metal is a platinum-based hydrocarbon conversion process catalyst, characterized in that contained in a molar ratio of 0.05 ~ 1: 99.95 ~ 99. The method of claim 1, The high-density ceramic oxide is alumina containing less than 5% by weight of magnesium, magnesium and calcium aluminate spinel oxide containing alumina, mullite, yttrium stabilized zirconia (YSZ), calcium stabilized zirconia (CSZ ), Alumina and cordierite (Cordierite) catalyst for the platinum-based hydrocarbon conversion process characterized in that. The method of claim 1, Platinum-based hydrocarbon conversion process catalyst, characterized in that the active metal platinum is contained 0.03 ~ 5% by weight in the composite carrier. The method of claim 1, Platinum and tin is a catalyst for a platinum-based hydrocarbon conversion process, characterized in that it is contained in a 1: 0.5 to 3.0 molar ratio. Alumina mixture containing 0.5 to 10 parts by weight of an organic acid and 0.1 to 5 parts by weight of a water-soluble polymer in a mixed solution containing 90 to 100% by weight of alumina sol, and 0 to 10% by weight of zirconia or titania sol. 1 step of preparing a composite carrier by coating the solution on the surface of the high-density ceramic oxide; To 100 parts by weight of the composite carrier of the first step, 0.1 to 10 parts by weight of platinum chloride dissolved in alcohol, 0.1 to 20 parts by weight of tin chloride and 1 to 10 parts by weight of inorganic acid were added, followed by reaction at a temperature of 25 to 80 ° C. To form a complex solution of platinum-tin; And Three steps of heat treatment by irradiating microwaves for 30 seconds to 10 minutes in a power range of 100 to 1500 W by supporting a complex carrier of one step in the platinum-tin complex solution of two steps; Method for producing a catalyst for the platinum-based hydrocarbon conversion process comprising a. The method of claim 9, 1 to 10 parts by weight of the surfactant based on 100 parts by weight of the one-step alumina mixed solution further comprises a method for producing a catalyst for a platinum-based hydrocarbon conversion process. The method of claim 9, The surfactant is a method for producing a catalyst for a platinum-based hydrocarbon conversion process, characterized in that selected from ionic surfactants, amphoteric polymer surfactants and Pluronic. The method of claim 9, The first step water-soluble polymer is a method for producing a catalyst for platinum-based hydrocarbon conversion process, characterized in that the ethylene glycol or methyl cellulose. The method of claim 9, The organic acid is a method for producing a catalyst for platinum-based hydrocarbon conversion process, characterized in that selected from citric acid, tartaric acid and oleic acid. The catalyst for a platinum-based hydrocarbon conversion process selected from claims 1 to 8 is a hydrocarbon conversion process characterized in that the dehydrogenation, reforming and selective CO oxidation reaction. The method of claim 14, The dehydrogenation reaction is characterized in that the dehydrogenation of the linear-paraffinic hydrocarbon is carried out under reaction conditions at a reaction temperature of 400 to 500 ° C., a reactor pressure of 0.5 to 5, and a space velocity (based on a liquid reactant) of 1 to 20 h ^−1. Hydrocarbon conversion process.

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