KR101485697B1 - An alkali-modified catalyst for dehydrogenation and dehydroisomerization of n-butane and a method for producing a mixture of n-butene, 1,3-butadiene and iso-butene with controlled ratio of isobutene to n-butene using the same - Google Patents

Abstract

The present invention relates to a catalyst for dehydrogenation and dehydroisomerization of n-butane modified by alkali metal addition and a method for manufacturing a mixture of n-butene, 1,3-butadiene and isobutene in which a production ratio of isobutene to n-butene is controlled in the dehydrogenation and dehydroisomerization of n-butane using the same and, more specifically, to a catalyst modified by adding alkali metal in which an addition ratio as compared with platinum is controlled to a chloridized catalyst in which alumina carriers are impregnated with platinum and tin, and to a method for manufacturing a high-yield mixture of n-butene, 1,3-butadiene and isobutene in which a production ratio of isobutene to n-butene is controlled in the dehydrogenation and dehydroisomerization of n-butane using the same.

Description

A catalyst for the dehydrogenation and dehydrogenation reaction of n-butane modified with an alkali metal and a mixture of n-butene, 1,3-butadiene and isobutene having controlled n-butene to isobutene production ratio from n-butane, And a method of producing an alkaline-modified catalyst for dehydrogenation and dehydroisomerization of n-butane and a method for producing a mixture of n-butene, 1,3-butadiene and iso-butene with controlled ratio of isobutene to n-butene using the same }

The present invention relates to a catalyst for dehydrogenation and dehydrogenation isomerization of n-butane modified by addition of alkali metal, and to a process for dehydrogenating and dehydrogenating isomerization of n-butane using the same, wherein n-butene to isobutene- , 1,3-butadiene and isobutene, and more particularly, to a process for preparing a mixture of 1,3-butadiene and isobutene, and more particularly, to a process for preparing a mixture of platinum and tin in a gamma- Butenes, isobutene, isobutene, 1,3-butadiene and isobutene with controlled yield ratio of n-butene to isobutene in dehydrogenation and dehydrogenation isomerization of n-butane using the same.

In recent years, the supply of light olefins, which are raw materials for various petrochemical products, has become a concern of the market due to the surge in olefin prices in the petrochemical market. Butenes, 1,3-butadiene, and isobutene, which are raw materials for various synthetic rubber and copolymer products, are also in the light olefins whose demand and value are increasing mainly in China, and methods for obtaining them include naphtha cracking, Dehydrogenation reaction of n-butane or n-butene, and dehydrogenation of isobutane. Of these, about 90% or more of n-butene, 1,3-butadiene and isobutene supplied to the market are supplied by the naphtha cracking process. In this situation, the operation of the naphtha cracking process has a great impact on the market . However, the naphtha cracking process is not a sole process for producing noble-butene, 1,3-butadiene, and isobutene due to the characteristics of processes for producing basic oils such as ethylene and propylene, , Naphtha crackers can not be newly added or expanded in order to expand production of 3-butadiene and isobutene, and even if naphtha crackers are added, other basic oils other than n-butene, 1,3-butadiene and isobutene are produced in surplus . In addition, recent trends in the establishment and operation of naphtha cracking processes are in the direction of higher yields as the demand for ethylene and propylene is greatly increased, and the yield of noble-butene, 1,3-butadiene and isobutene , But the process has been changed to a process using light hydrocarbons such as ethane and propane, which have a high yield relative to other basic oils such as ethylene and propylene, as raw materials. In addition, since the naphtha raw material that can obtain noble-butene, 1,3-butadiene, and isobutene oil is continuously increased in price, and the ratio of naphtha cracking process is relatively reduced accordingly, It is becoming increasingly difficult to secure a mixture of n-butene, 1,3-butadiene and isobutene, i.e., n-butene, 1,3-butadiene and isobutene through the naphtha cracking process.

Thus, the naphtha cracking process accounts for most of the mixture of n-butene, 1,3-butadiene and isobutene, such as n-butene, 1,3-butadiene and isobutene, It is not an effective alternative to solve the imbalance in supply and demand. For this reason, the reaction of obtaining n-butene and 1,3-butadiene by dehydrogenating hydrogen from n-butane or n-butene or obtaining isobutene by dehydrogenation of isobutane is the most recent reaction of n-butene , 1,3-butadiene, and isobutene.

Normal-to catalysts used in the dehydrogenation process of butane and isobutane is mainly alumina (Al ₂ O ₃₎ to the carrying platinum (Pt) and tin (Sn) catalyst to the carrier, chromia (Cr ₂ O ₃ ) as a main component are known.

Representative processes using chromia-alumina-based catalysts include Houdry process for producing n-butene from n-butane, and process for producing 1,3-butadiene from n-butane, UCI-ABB Lummus Crest's CatadieneTM process.

The dehydrogenation process using platinum (Pt) as the main catalyst component was developed from the end of the 1960s and was able to continuously operate the noble metal catalyst device in the early 1970s without shutting down the process unit for a long time The Oleflex process of UOP, a dehydrogenation process, has been developed but is now being applied to the production of propylene and isobutylene.

Conventionally, a catalyst mainly composed of platinum and tin is generally used as a carrier, and gamma (?) Crystalline alumina (Al ₂ O ₃ ) having a nitrogen adsorption specific surface area of 150 m ² / g or more and a high purity of 99.9% And further using an alkali metal or an alkaline earth metal to adjust the acid point of the catalyst is known.

Gamma (γ) crystalline alumina itself has a strong acid point, which is likely to cause side reactions. The strong acid sites cause cracking of the hydrocarbons, which reduces the olefin selectivity of the dehydrogenation reaction or causes the deposition of hydrocarbons (caulking) Resulting in loss of the hydrocarbon component as a raw material and lowering of the yield of olefin.

For this reason, in the dehydrogenation process of an alkane, a catalyst prepared by neutralizing or adjusting a acid site by adding an alkali metal or an alkaline earth metal is generally used in order to minimize side reactions caused by the acid sites of the catalyst support. US Pat. No. 4,677,237 discloses a catalyst Catalyst technology has been introduced that improves performance by supporting alkaline alkali metal on alumina to prevent shrinkage.

U.S. Patent No. 4,886,928 contains platinum and tin, ytterbium, alkali metals or alkaline earth metals in the dehydrogenation reaction of C2-C5 normal-paraffin or isoparaffin and the chlorine (Cl) content is less than 0.25 wt% A controlled catalyst is described.

U.S. Patent No. 5,151,401 discloses a method in which chlorine is sufficiently removed through a separate washing process after a calcination process in a catalyst in which zinc aluminate (ZnAl ₂ O ₄ ) is used as a carrier and platinum and tin are supported as main components, By weight to not more than 0.05% by weight.

Thus, the conventional alkane dehydrogenation catalyst intentionally removes chlorine (Cl) through the final calcining process of the catalyst or a separate washing or steaming treatment, and even if there is residual chlorine unavoidably, Is minimized and used.

On the other hand, the naphtha reforming process is a process for converting n-paraffins and naphthenes into aromatic hydrocarbons, and the acid function is essential for the production of aromatic compounds. For this reason, catalysts of the type including one or more other metals and platinum deposited on a chlorinated aluminum oxide carrier have been known for a long time in the naphtha-reforming process.

That is, unlike the dehydrogenation process of normal-paraffin which has a negative effect on the acid sites, the acid sites play an important role in the naphtha reforming process, so that the carrier is chlorinated rather than neutral or alkali treated carrier, Is used. In addition, in order to maintain the acidic function of the catalyst in the process, a chlorine compound is continuously supplied to the system to supplement the acidic function.

In the naphtha-reforming process carried out on such a catalyst, a carbon-containing complex is generated by side reaction in the continuous contact process of the catalyst with the raw material simultaneously with the chemical conversion reaction of the paraffin and naphthenic hydrocarbon compound into the aromatic compound, . Such a carbonaceous complex or coke plugs the catalytically active site and interferes with the access of the reactant, and becomes a factor of inactivation of the catalyst. For this reason, on an industrial scale, after a period of hydrocarbon conversion reactions, the coke must be removed. This is done through the catalyst regeneration process. During the total period of use of the catalyst, the catalyst undergoes several regeneration steps until the catalyst becomes no longer usable and is replaced. This regeneration process generally involves the removal of coke deposited on the catalyst by burning, the drying of water produced in the combustion process, and the re-dispersion of the platinum (Pt) component sintered in the course of the reaction and coke combustion. And an oxychlorination step carried out in the presence of an oxidizing agent.

When the catalyst in the naphtha-reforming process is repeatedly cycled through such a reaction-regeneration step, a change in the structural characteristics such as a reduction in the surface area of alumina occurs largely, which in turn affects the naphtha-reforming reaction, Which is directly related to the lowering of the lifetime. For example, a reduction in surface area can cause sintering and coagulation of the finely dispersed active components, rendering catalyst activity itself impossible.

As described above, even though the dehydrogenation catalyst and the naphtha-reforming catalyst have a common feature that platinum and tin are the main components, the required catalyst characteristics are different and the reaction conditions are different. While the dehydrogenation process benefits from low pressures for high conversion rates, the naphtha reforming process is typically carried out under high pressure conditions, and additionally chlorine is added continuously to maintain the acid point function.

In addition, in the case of the naphtha-reforming catalyst, periodic regeneration process is required due to the precipitated coke in the reaction process. In this process, the structural change due to deterioration and thus the reduction of the specific surface area of the carrier are caused. Thus, over time, naphtha-reforming catalysts exhibit physical properties that differ from those at the initial point of time when they were loaded into the reactor.

Separately, the conversion of n-butene to isobutene is an isomerization reaction in which a part of the bond forming the backbone of the molecule is rearranged and rearranged, so-called skeletal isomerization. The skeleton isomerization of n-butene to isobutene requires that the activated n-butene is reacted with skeleton isomerization through a single-molecule reaction mechanism at the acid site, so that the isobutene production rate is increased and the n-butene is activated at the B- (J. Korean Ind. Eng. Chem., Vol. 15, No. 6, 581-593 (2004)). Therefore, in the isomerization reaction of n-butene to isobutene, the strength, kind and concentration of acid sites are important factors affecting selectivity and yield.

The present inventors have found that, in the process of studying a catalyst capable of converting n-butane into a mixture of n-butene, 1,3-butadiene and isobutene, the naphtha-reforming catalyst aged through repetitive reaction- Butene, 1,3-butadiene and isobutene can be produced by high heat treatment under specific temperature conditions and reducing atmosphere at the point of coke combustion removal, water drying and oxychlorination treatment. (Korean Patent Application No. 2012-0080194).

However, the catalyst of the above-mentioned patent application has a problem that the production ratio of n-butene and isobutene having different uses and demands in the product is fixed, dehydrogenation with a carbon number of 4, which still produces a large amount of C1-C3 by-products due to side reactions such as cracking, The selectivity to the products of the dehydrogenation isomerization, that is, the mixture of n-butene, 1,3-butadiene and isobutene, is low, and the deactivation rate is fast.

The present inventors have found that a catalyst having characteristics of a catalyst aged gradually over time by a repetitive cycle of reaction-regeneration of a naphtha-reforming catalyst containing platinum and tin as a main component is subjected to coke combustion removal, moisture drying and oxychlorination When the alkali metal component is added at a rough point to modify the alkaline metal component and, in particular, the addition ratio of the alkali metal to the platinum in the catalyst component is adjusted, the dehydrogenation of the n-butane and the dehydrogenation isomerization of the n- Butene and 1,3-butadiene are greatly improved and the problem of deactivation is greatly improved, so that a mixture of n-butene, 1,3-butadiene and isobutene Can be produced at a high yield. Thus, the present invention has been completed.

Accordingly, an object of the present invention is to provide a process for producing a mixture of n-butene, 1,3-butadiene and isobutene by simultaneously performing a dehydrogenation reaction of n-butane and a dehydrogenation isomerization reaction using n-butane as a raw material Modified catalyst capable of regulating the ratio of n-butene to isobutene formation by adding alkali metal and capable of producing a mixture of n-butene, 1,3-butadiene and isobutene with high selectivity and yield, Butane, 1,3-butadiene and isobutene in a high yield by means of dehydrogenation of n-butane and dehydrogenation isomerization of n-butene, 1,3-butadiene and isobutene.

The catalyst used in the dehydrogenation reaction and the dehydrogenation isomerization reaction of n-butane according to the present invention is characterized in that platinum and tin are supported on a gamma alumina carrier, the catalyst is chlorinated to contain excess chlorine, Wherein the weight ratio of chlorine to platinum is 1: 3 to 10: 1, the specific surface area of the catalyst is 100 to 180 m ^2, / g is further modified by introducing an alkali metal component into the catalyst. In this case, the amount of the alkali metal component to be introduced is 0.1 to 3% by weight based on the total weight of the catalyst before introduction of the alkali metal component in the range of 1 to 30 atomic ratios of the added alkali metal to platinum.

In the present invention, as long as the catalyst to be subjected to the reforming treatment by the addition of the alkali metal has the above-described composition and characteristics, there is no particular limitation on its kind, and for example, platinum used in a conventional naphtha- - a naphtha-reforming regenerated catalyst in which a tin catalyst is treated with a conventional catalyst regeneration treatment process consisting of a coke combustion removal, a water drying and an oxychlorination treatment may be used, or a separately prepared catalyst may be used It is possible.

Typical methods for preparing such naphthafluoroforming catalysts include, for example, the methods described in the examples of Korean Patent No. 10-0569853 and the methods of Examples of Korean Patent No. 10-0736189. Specifically, according to Example 1 of Korean Patent No. 10-0569853, tin chloride (tin chloride) and aqueous hydrochloric acid solution were added to gamma alumina having a specific surface area of 210 m ² / g, followed by dehydration after contacting for 3 hours, Subsequently, a hexachloroplatinic acid aqueous solution of a platinum compound is brought into contact. Thereafter, the catalyst is dried at 120 ° C. for 1 hour and then calcined at 500 ° C. for 2 hours to obtain a platinum / tin naphtha reforming catalyst (PtSn / γ-Al ₂ O ₃ ). According to Example 1 of Korean Patent No. 10-0736189, a tin chloride aqueous solution is added to 100 g of gamma alumina having a specific surface area of 200 m ² / g in the presence of hydrochloric acid and nitric acid, and the mixture is contacted for 3 hours, Dried at 120 ° C and then calcined at 500 ° C for 2 hours under air circulation. Subsequently, this solid was contacted with an aqueous solution of hexachloroplatinic acid, dried at 120 ° C for 1 hour, and then calcined at 500 ° C for 2 hours under air flow. The catalyst is then reduced at 500 캜 for 4 hours under a hydrogen flow to obtain a platinum / tin naphtha reforming catalyst (PtSn / γ-Al ₂ O ₃ ).

In the catalyst of the present invention, gamma-alumina, which is a carrier, is the most commonly used carrier component for industrially supporting highly dispersed noble metal components, and is not limited in its kind, and preferably has a ratio of 180 to 250 m ² / g Having a surface area can be used.

In the catalyst of the present invention, the platinum is used as a main metal serving as a catalytic active site, and the content of the platinum in the catalyst is preferably 0.1 to 1.0 wt%. If less than 0.1 wt% The conversion rate may be lowered. If the content is more than 1.0% by weight, the degree of dispersion of platinum is lowered and utilization of platinum, which is a high-priced noble metal, may be lowered.

In the catalyst of the present invention, the tin is used as an auxiliary metal to serve as a cocatalyst. If the content of tin is less than 0.1 wt%, the desired tin can not be expected to act as a cocatalyst, , The activity may be lowered by reducing the platinum active site, which is undesirable.

In the catalyst of the present invention, it is preferable that the content of chlorine is 0.5 to 3.0 wt%. If the amount of chlorine is less than 0.5 wt%, it is not possible to provide an appropriate acid point and dehydroisomerization of n-butane can not proceed properly. If the content is more than 10 wt%, the activity of the catalyst may be lowered due to poisoning of the noble metal by chlorine, which is not preferable.

In the catalyst of the present invention, it is preferable that the weight ratio of chlorine to platinum is in the range of 1: 3 to 10: 1. If the ratio is outside the above range, the balance between the metal function and the acid point function is broken, Or excessive acid sites may increase the side reaction or poisoning of the noble metal by chlorine may lower the activity of the catalyst.

The specific surface area of the catalyst of the present invention is preferably 100 to 180 m ² / g. If the amount of the catalyst is outside the above range, sintering and coagulation of the finely dispersed active components may be caused, not.

In the catalyst of the present invention, the alkali metal is potassium (K), sodium (Na), or cesium (Cs). If the addition amount of the alkali metal is less than 0.1% by weight, it is impossible to expect the desired noble-butene-to-isobutene production ratio control effect. If it exceeds 3.0% by weight, the platinum activation point may be decreased, Which is undesirable.

The method of introducing the alkali metal added to the catalyst according to the present invention is not particularly limited as long as it has the above-described composition and characteristics. For example, an alkali metal precursor compound solution can be prepared by impregnating a PtSn / γ-Al ₂ O ₃ -Cl catalyst with a dry-heat treatment step.

The alkali metal precursor compound to be used in the present invention can be any alkali metal compound conventionally used without any limitation, and examples thereof include alkali metal nitrate (NaNO ₃ , KNO ₃ , CsNO _3, etc.) But is not limited thereto. Drying after impregnation is intended to remove moisture after impregnation with an alkali metal compound. Drying temperature and drying time can be limited according to general moisture drying conditions. For example, drying temperature is 50 to 200 ° C, preferably 80 To 150 ° C, and the drying time may be set to 3 to 48 hours, preferably 6 to 24 hours.

In addition, the heat treatment after drying is a step of decomposing and removing the salt in the alkali metal compound after the water is removed through impregnation and drying of the alkali metal precursor compound.

The heat treatment may be performed at 200 to 700 ° C for 1 to 24 hours, preferably 300 to 600 ° C for 2 to 12 hours under a nitrogen atmosphere or an air atmosphere. If the heat treatment temperature is less than 300 ° C or the heat treatment time is less than 1 hour, the effect of heat treatment may be insufficient. If the heat treatment temperature exceeds 700 ° C or the heat treatment time exceeds 24 hours, It is undesirable that the activity may be reduced by formation of excessive alloying between metals.

In addition, the catalyst of the present invention may be subjected to an appropriate reduction treatment in order to exhibit the performance in the dehydrogenation and dehydrogenation isomerization of n-butane, which may be carried out in an actual process or through a reduction process in advance. The catalyst of the present invention flows hydrogen gas mixed with pure hydrogen or nitrogen at a gas hourly space velocity (GHSV) of 0 to 2,000 cc / hr / g.cat, and is reduced at 400 to 700 ° C for 0.1 to 24 hours , It is possible to express sufficient activity.

The process for preparing a mixture of n-butene, 1,3-butadiene and isobutene by dehydrogenation and dehydrogenation isomerization of n-butane according to the present invention is characterized in that n-butane is used as a raw material To carry out dehydrogenation and dehydrogenation isomerization.

According to the process for preparing a mixture of n-butene, 1,3-butadiene and isobutene by dehydrogenation and dehydrogenation isomerization of n-butane according to the present invention, compared with the case of using a catalyst containing no alkali metal, The selectivity to n-butene and 1,3-butadiene can be improved by decreasing the production ratio of isobutene to butene. Specifically, the production of isobutene to n-butene in the product according to the process of the present invention Ratio is controlled to be less than 0.6.

In the process for preparing a mixture of n-butene, 1,3-butadiene and isobutene by dehydrogenation and dehydrogenation isomerization of n-butane according to the present invention, the temperature of the dehydrogenation and dehydrogenation isomerization is 400 to 700 ° C , Preferably 500 to 700 ° C, and more preferably 450 to 600 ° C. The pressure is preferably 0 to 10 atm, preferably 0.01 to 5 atm, and the normal-butane space velocity (GHSV) ^-1 , preferably 100 to 5000 hr ^-1 . When the reaction conditions are out of the above ranges, the reaction does not sufficiently take place and the catalyst may not be used properly or the economical efficiency may be deteriorated in terms of effectively utilizing the catalyst. Further, (Operation), and in some cases, unwanted side reactions on the catalyst may be increased or the deactivation may be promoted. Conversely, if the raw material By the input unnecessarily excessive undesirable can lead to increased operating cost of the separation of the recycled raw material.

In the dehydrogenation and dehydrogenation isomerization, hydrogen may be further added to the normal-butane stream, and the number of moles of hydrogen with respect to 1 mole of n-butane may be 0.1 to 100 moles, preferably 1 to 10 moles. The hydrogen acts to remove carbon deposits formed on the surface of the catalyst, for example, coke.

In the dehydrogenation and dehydrogenation isomerization reaction, if necessary, a diluent such as nitrogen, an inert gas or steam may be mixed in addition to the normal-butane.

According to the present invention, when the naphtha-reforming catalyst is gradually aged and the catalyst characteristics are changed as a result of exposure to the reaction-regeneration process repeated in the conversion reaction of paraffin and naphthene into aromatics, The present invention provides a method which can be usefully used in a reaction for converting a regenerated catalyst having physical properties into a dehydrogenation derivative of n-butane different from its intended use.

In addition, when the catalyst of the present invention is used, dehydrogenation and dehydrogenation isomerization reaction of n-butane can regulate the production ratio of n-butene and isobutene when converted into a high-value product having high utilization value, Has a high effect.

When the catalyst of the present invention is used, it exhibits high activity in dehydrogenation and dehydrogenation isomerization of n-butane through deactivation relaxation, high selectivity for n-butene, 1,3-butadiene and isobutene, A mixture of 1,3-butadiene and isobutene can be obtained at a high yield.

1 is a graph showing the relationship between the total yield of n-butene, 1,3-butadiene and isobutene produced by dehydrogenation and dehydrogenation isomerization of n-butane over five catalysts according to Examples 1 to 4 of the present invention and Comparative Example 1 As shown in FIG.

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

<Analysis of raw material catalyst>

A process for producing a conventional naphtha-reforming catalyst, that is, impregnation of gamma alumina with tin, followed by calcination at 500 DEG C, then calcination at 500 DEG C with platinum supported thereon, reduction at 500 DEG C / Tin system naphtha reforming catalyst is used in a naphtha reforming process, the catalyst whose performance has been reduced by the coke is regenerated through coke combustion-water-drying-oxychlorination treatment by a conventional regeneration treatment method, The results of analyzing the characteristics of the regenerated catalyst (PtSn / Al ₂ O ₃ -Cl), which was repeated several times after the regeneration process, are shown in Table 1 below.

Catalysts having the compositions and characteristics of Table 1 were used in the following Comparative Examples and Examples.

Example  One

A catalyst modified by K addition was prepared as follows so that the amount of K added to the raw material catalyst (PtSn / Al ₂ O ₃ -Cl) was 0.35 wt%. After 90.4 mg of potassium nitrate (KNO ₃ ) was dissolved in distilled water, 10 g of a PtSn / Al ₂ O ₃ -Cl catalyst was impregnated into this solution and dried at 110 ° C for 8 hours. Thereafter, heat treatment was carried out under conditions of a dry air space velocity of 1500 hr &lt; ^-1 &gt; and an air flow at 550 DEG C for 3 hours. This catalyst was named PtSnK (0.35). 2 g of the catalyst PtSnK (0.35) thus heat-treated was charged into the reactor, and the catalyst was reduced at 570 ° C for 2 hours while flowing a mixed gas of 20 cc of pure hydrogen and 20 cc of nitrogen.

Then, the dehydrogenation reaction was carried out by introducing nitrogen and n-butane mixed gas. The gas-space velocity (GHSV) of the normal-butane was 600 hr ^-1 , the mixing volume ratio of nitrogen and n-butane was 1: 1, and the reaction temperature of the catalyst layer was maintained at 550 ° C. at normal pressure.

The gas composition formed by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane after 1 hour from the initiation of reaction and the selectivity of each reaction product were measured and are shown in Table 2 below. Further, the change in the total yield of n-butene, 1,3-butadiene and isobutene with time is shown in Fig.

The conversion of n-butane, the selectivity and yield of each reaction product were calculated by the following equations (1), (2) and (3).

[Equation 1]

 &Quot; (2) &quot;

 &Quot; (3) &quot;

Comparative Example 1

2 g of the raw material catalyst was heat-treated under air flow at a dry air space velocity of 1500 hr ^-1 at 550 ° C. for 3 hours without adding an alkali metal. This catalyst was named PtSn (NA). The catalyst was charged into a reactor and the catalyst was reduced at 570 캜 for 2 hours while flowing a mixed gas of 20 cc of pure hydrogen and 20 cc of nitrogen. Then, the dehydrogenation reaction was carried out by introducing nitrogen and n-butane mixed gas. The gas-space velocity (GHSV) of the normal-butane was 600 hr ^-1 , the mixing volume ratio of nitrogen and n-butane was 1: 1, and the reaction temperature of the catalyst layer was maintained at 550 ° C. at normal pressure.

The gas composition formed by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane after 1 hour from the initiation of reaction and the selectivity of each reaction product were measured and are shown in Table 2 below. Further, the change in the total yield of n-butene, 1,3-butadiene and isobutene with time is shown in Fig.

Example 2

The procedure of Example 1 was repeated except that the amount of K added to the raw material catalyst was changed to 0.5 wt%. This catalyst was named PtSnK (0.5). The gas composition formed by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane after 1 hour from the initiation of reaction and the selectivity of each reaction product were measured and are shown in Table 2 below. Further, the change in the total yield of n-butene, 1,3-butadiene and isobutene with time is shown in Fig.

Example  3

The procedure of Example 1 was repeated except that the amount of K added to the raw material catalyst was changed to 0.7 wt%. This catalyst was named PtSnK (0.7). The gas composition formed by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane after 1 hour from the initiation of reaction and the selectivity of each reaction product were measured and are shown in Table 2 below. Further, the change in the total yield of n-butene, 1,3-butadiene and isobutene with time is shown in Fig.

Example  4

The procedure of Example 1 was repeated except that the amount of K added to the raw material catalyst was changed to 1.0 wt%. This catalyst was named PtSnK (1.0). The gas composition formed by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane after 1 hour from the initiation of reaction and the selectivity of each reaction product were measured and are shown in Table 2 below. Further, the change in the total yield of n-butene, 1,3-butadiene and isobutene with time is shown in Fig.

Example  5

The procedure of Example 1 was repeated except that Cs was added in an amount of 0.5 wt% instead of K as an alkali metal to be introduced into the raw material catalyst. This catalyst was named PtSnCs (0.5). The composition of the gas produced by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane and the selectivity of each reaction product were measured and shown in Table 3 below.

Example  6

The procedure of Example 5 was repeated, except that the amount of Cs added to the raw material catalyst was changed to 0.7 wt%. This catalyst was named PtSnCs (0.7). The composition of the gas produced by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane and the selectivity of each reaction product were measured and shown in Table 3 below.

Example  7

The procedure of Example 5 was repeated except that the amount of Cs added to the raw material catalyst was changed to 1.0 wt%. This catalyst was named PtSnCs (1.0). The composition of the gas produced by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane and the selectivity of each reaction product were measured and shown in Table 3 below.

Example  8

The procedure of Example 5 was repeated except that the amount of Cs added to the raw material catalyst was changed to 2.0 wt%. This catalyst was named PtSnCs (2.0). The composition of the gas produced by the reaction was analyzed by GC for gas analysis connected to the reaction apparatus. From this, the conversion of n-butane and the selectivity of each reaction product were measured and shown in Table 3 below.

 Note 1) The atomic ratio of added potassium (K) to platinum (Pt)

2) 1,3-butadiene selectivity

3) Production ratio of isobutene to n-butene in the product

4) The total yield of n-butene, 1,3-butadiene and isobutene, products of dehydrogenation and dehydrogenation isomerization of n-butane

Note 1) The atomic ratio of added cesium (Cs) to platinum (Pt)

2) 1,3-butadiene selectivity

3) Production ratio of isobutene to n-butene in the product

4) The total yield of n-butene, 1,3-butadiene and isobutene, products of dehydrogenation and dehydrogenation isomerization of n-butane

As can be seen from Table 2, in the catalysts to which potassium was added in Examples 1 to 4, as the atomic ratio of added potassium to platinum was increased, dehydrogenation of n-butane and normal- It can be seen that the isobutene production ratio for butene is reduced. Also, it can be seen that the total yield of n-butene, 1,3-butadiene and isobutene is greatly improved. Also, as shown in FIG. 1, it can be seen that the yield is maintained as a whole during the course of the reaction.

As can be seen from Table 3, in the catalysts to which cesium was added in Examples 5 to 8, as the atomic ratio of added cesium to platinum was increased, dehydrogenation of n-butane and dehydrogenation of n-heptane- It can be seen that the isobutene production ratio for butene is reduced. It is also seen that the total yields for n-butene, 1,3-butadiene and isobutene are improved.

Claims (7)

0.1 to 1.0% by weight of platinum, 0.1 to 2.0% by weight of tin and 0.1 to 2.0% by weight of chlorine, based on the total weight of the catalyst, of the regenerated catalyst used in the naphtha reforming step, To 3.0% by weight, the weight ratio of chlorine to platinum is platinum: chlorine = 1: 3 to 10, and the specific surface area is 100 to 180 m ² / g. In addition to the raw material catalyst, an alkali metal is added to the platinum- Wherein the catalyst is modified by adding 0.1 to 3% by weight based on the total weight of the raw material catalyst in the range of 1 to 30 atomic ratios of the raw material catalyst to the dehydration and dehydrogenation isomerization reaction of n-butane. delete The method according to claim 1,
Wherein the alkali metal is potassium (K), sodium (Na), or cesium (Cs). A process for producing n-butene, 1,3-butadiene and isobutene, which comprises subjecting a catalyst according to claim 1 or 3 to dehydrogenation and dehydrogenation isomerization using n-butane as a raw material. &Lt; / RTI &gt; 5. The method of claim 4,
Butene, 1,3-butadiene and isobutene, wherein the ratio of isobutene to n-butene in the mixture of n-butene, 1,3-butadiene and isobutene is controlled to be less than 0.6. Way. 5. The method of claim 4,
The dehydrogenation and dehydrogenation isomerization of the n-butane are carried out under the conditions of 400 to 700 ° C., 0.1 to 10 atm and a normal-butane space velocity of 50 to 5000 hr ^-1 . - Preparation of a mixture of butadiene and isobutene. The method according to claim 6,
Butane is further added with hydrogen in the normal-butane stream in the dehydrogenation and dehydrogenation isomerization of the n-butane and the molar ratio of hydrogen to 1 mole of n-butane is 0.1 to 100, A process for preparing a mixture of 3-butadiene and isobutene.

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