MXPA98009838A - Catalyst preparation process to produce alquenilo acetates and use of the catalyst prepared through this proc - Google Patents

Abstract

The ent invention relates to a process for aring a catalyst comprising a noble metal, and a metal as the promoter of the catalysis, in combination with an alkaline or alkaline earth metal compound, supported on the external surface of a carrier. The aration process comprises imnating the carrier with a solution containing a noble metal in the oxidation state, as the main catalyst, and a metal in the oxidation state as the promoter of the catalysis, reducing metals in the oxidation state to the metallic state , in gaseous phase, with a gaseous reducing agent, under certain temperature, sure and concentration of the gas, then imnate the reduced carrier with a solution of an alkaline or alkaline earth metal compound. The catalyst supporting the metal components, ared by the process according to the ent invention, has a high surface area and exhibits a high catalytic activity, which leads to an increase in the catalytic efficiency and life of this heterogeneous catalyst. The catalyst ared in the ent invention is convenient for producing alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in the vap phase

Description

CATALYTIC PREPARATION PROCESS TO PRODUCE ALQUENILO ACETATES AND USE OF THE CATALYST PREPARED THROUGH THIS PROCESS FIELD OF THE INVENTION This invention relates to a process for the preparation of a catalyst comprising noble metals as the main component and the metals as the promoter of the catalysis, in combination with an alkaline or alkaline earth metal compound, supported on the outer surface of a carrier. , and also refers to the use of a catalyst prepared according to the process of the present invention, to produce alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in the vapor phase.

BACKGROUND OF THE INVENTION The industrial production of alkenyl acetates through the reaction of olefins, oxygen and acetic acid, in vapor phase, has been carried out in the presence of a REF catalyst. : 28901 heterogeneous, which comprises noble metals, metals as promoters of the catalysis, in combination with an alkaline or alkaline earth metal compound, supported on the outer surface of a carrier. This preparation process has been known for a long time and the key point of this process, the uniform distribution of metal components on the surface of a support catalyst to provide high performance, has also been discussed and studied, mainly based on the change or type of relative composition of the metallic components. However, no matter how the composition of the metal or its structure has changed, the basic structure of all catalysts for producing alkenyl acetates is essentially a spherical catalyst prepared by impregnation on a carrier with the palladium metal, a metal for promoting catalysis, and an alkaline or alkaline earth metal compound, wherein the metal for promoting catalysis is preferably gold and copper, and wherein the alkali metal or alkaline earth metal compound is preferably a potassium compound (US Patent No. 3939199, European Patent No. 0361484 and North American Patent No. 4668819). Previously the catalyst used to produce vinyl acetate was prepared by impregnating palladium, gold and similar noble metals, especially the carrier (US Patent No. 3725680 and No. 3743607); the catalyst used to produce allyl acetate was prepared by impregnating palladium, copper and similar noble metals, especially the carrier (North American Patent No. 39177676). That is, they were supported on the inner and outer surface of a carrier. However, although the catalyst was prepared in this way, it was found in a real reaction that the reactants were barely able to efficiently diffuse into the interior regions of the carrier, such that the active metals, palladium and gold or copper, do not They were able to be used enough. To improve this disadvantage, in the process of preparing the catalyst to produce alkenyl acetates, usually, instead of impregnating the palladium metal and a metal to promote catalysis, especially the carrier, it is uniformly impregnated on the surface of a carrier. . That is, to impregnate palladium metal and the metal promoting the catalysis, uniformly, on the surface layer of a carrier, to form a supported spherical catalyst (US Patent No. 4087622). The method of preparation was that in which the carrier was impregnated first with the active metallic materials, then these metal salts were precipitated by immersion in a solution containing alkali metal or alkaline earth metal salts (US Patent No. 4048096 and US Patent No. 3775342). In addition, it was known that when the catalyst was prepared with metals of palladium and other metals as promoters of the catalysis, in combination with an alkaline or alkaline earth metal, a special carrier was used. This carrier was washed with acids before impregnation and treated with bases after impregnation (E P-A-0519435). Since palladium and metal to promote catalysis were non-homogeneous during impregnation, which would have resulted in an inhomogeneous distribution on the surface of a carrier, then much research has been done regarding this problem (US Patent No. No. 4987622, U.S. Patent No. 3822308 and British Patent 1521652). As a result, in the preparation of the catalyst for producing alkenyl acetates, the catalyst was prepared by essentially impregnating palladium and a metal to promote catalysis, in combination with an alkaline or alkaline earth metal compound, on the surface of a spherical carrier. The preparation process is: generally comprised of the following steps (1) a carrier was impregnated with an aqueous solution of soluble palladium ions and metal ions to promote catalysis; (2) The impregnated carrier was immersed in an alkaline solution, such that soluble palladium ions and metal ions to promote catalysis were precipitated on the surface layer of the carrier and formed a palladium within an insoluble oxidation state and a metal to promote catalysis; (3) the treated carrier was washed with water to remove the soluble ions produced during the precipitation; (4) the palladium in the oxidation state and the metal to promote the catalysis, supported on the treated carrier, were then reduced to the metallic state; (5) the carrier reduced in (4) was impregnated with a solution of an alkali metal or alkaline earth metal compound; and (6) the carrier impregnated in (5) was dried. Among these steps, conventionally, the reducing step (4) was performed by a reduction process using liquid reducing agents, in liquid phase. However, given the inhomogeneous nature of the palladium and the metal used as a promoter of the catalysis, on the surface of the carrier, the catalyst prepared by this method is usually instructive. To solve the problem, in the process of preparing the catalyst to produce alkenyl acetates according to the present invention, the conventional reduction process, which uses liquid reducing agents, in liquid phase, is changed by a reduction process that uses gaseous reducing agents in gas phase. As a result, the catalyst comprising palladium and a metal as promoter of the catalysis, in combination with an alkali and alkaline earth metal compound, supported on a carrier prepared by the use of the present invention, has a high metal surface area, and exhibits high catalytic activity, and in this way the catalytic efficiency and life of this heterogeneous catalyst is improved.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to a process for preparing a catalyst comprising a noble metal and a metal as promoter of the catalysis, in combination with an alkali metal or alkaline earth metal compound, supported on the outer surface of a carrier. The preparation process comprises impregnating the carrier with a solution containing a noble metal in the oxidation state, as the main catalyst, and a metal in the oxidation state, as the promoter of the catalysis, reducing metals in the oxidation state, metallic state, in gaseous phase, with a gaseous reducing agent, under certain temperature, pressure and concentration of the gas, then impregnate the reduced carrier with a solution of an alkaline or alkaline earth metal compound. The support catalyst of the metal components, prepared by the process according to the present invention, has a high surface area and exhibits high catalytic activity, which leads to the increase of the catalytic efficiency and the life of the heterogeneous catalyst. The catalyst prepared in the present invention is convenient for producing alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in the vapor phase.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a process for preparing a catalyst comprising a noble metal as the main component and other metals as promoters of the catalysis, in combination with an alkali metal or alkaline earth metal compound, all of which are supported on the outer surface of a carrier Examples of suitable carriers are alumina, silica gel, silica, activated carbon, silicon carbide, diatomaceous earths, pumice and the like, although silica is preferred among them. The example of noble metal is palladium; Examples of metals used as promoters of catalysis are gold, copper, molybdenum, cadmium and magnesium, although gold and copper are preferred among them. Examples of the alkali metal or alkaline earth metal compounds are the hydroxides, acetates, nitrates and bicarbonates of potassium, sodium, cesium, magnesium, barium and the like, although among them potassium salts are preferred, and even more preferred is sodium acetate. potassium. The distinctive feature of the process according to the present invention is, in the preparation of the catalyst to produce alkenyl acetates, is that the conventional reduction process using liquid reducing agents, in liquid phase, is changed by a reduction process that uses gaseous reducing agents, in gaseous phase, to carry out the reduction of the metals in the oxidation state. After the treatment with an alkaline solution for transferring the noble metal in the oxidation state and the metal to promote the catalysis (which are supported on the carrier after impregnation), in the hydroxide state, these are reduced with suitable gaseous reducing agents. , under specific reducing conditions and are transformed to the metallic state. The term "oxidation state", as used in accordance with the present invention, means a metal in the cationic state, for example, palladium in the oxidation state means Pd2 +. In the preparation process according to the present invention, after the metal components are supported on the surface layer of the carrier, by a well-known conventional method, the catalyst not hitherto reduced is placed in a reactor, and is used a gaseous reducing agent, under suitable reducing conditions, in gaseous phase, to reduce the metals that are in the oxidation state, in metals that are in the metallic state. Although examples of gaseous reducing agents used in the present invention are hydrogen and ethylene, hydrogen is preferable. In the reduction process, it is preferable to dilute the gaseous reducing agent with inert gas (such as nitrogen gas). The volumetric percentage of the reducing agent after dilution is in the range of 0.05 to 75%, and preferably, 5 to 30%. The amount of the reducing agent used depends on the amounts of the noble metal and the metal to promote catalysis; the equivalents used thereof will usually be at least 1 to 1.5 times that of the equivalents required to reduce the catalyst; if necessary, more reducing agents can be used. The reduction temperature is usually between 100 and 300 ° C, and preferably between 150 and 200 ° C. The pressure for the reduction is usually between 0 and 5 kg / cm2 (gauge pressure), and preferably between 1.5 and 3.5 kg / cm2 (gauge pressure). After the reduction process, the reduced catalyst is washed with deionized water until the chloride ions are completely removed and then dried. After drying, it is impregnated with an aqueous solution containing an alkali metal or anionic metal compound. Finally, the catalyst is dried at a temperature between 80 and 150 ° C until the water content is between 0 and 6% by weight, and preferably between 1 and 3% by weight. The support catalyst of the metal components, prepared in the present invention, is suitable for producing alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in the vapor phase. Olefinic compounds include ethylene, propylene, isobutylene and the like. For example, the catalyst prepared in the present invention can be used in the presence of ethylene, acetic acid and oxygen, in vapor phase, to produce vinyl acetate. The catalyst used in this production process comprises palladium, gold and an alkaline or alkaline earth metal compound (a potassium compound is preferred). Also, the catalyst prepared in the present invention can be used in the presence of propylene, acetic acid and oxygen, in vapor phase, to produce allyl acetate. The catalyst used in this production process comprises palladium, copper (in addition barium and lead can be added), and an alkaline or alkaline earth metal compound (a potassium compound is preferred). A certain amount of the previously prepared catalyst is placed to produce alkenyl acetates in a reaction tube which has an internal diameter of 20 mm and a length of 2.0 m. Under a specific pressure at the inlet of the reaction tube, the reaction gases are introduced into the tube at a reaction temperature adjusted according to the activity of the catalyst. These reaction gases comprise from 30 to 45% by volume of olefin, from 30 to 50% by volume of nitrogen gas, from 5 to 15% by volume of acetic acid and from 3 to 7% by volume of oxygen. The production of alkenyl acetate is determined by analyzing the outlet of the tube, in a defined time. Generally, the selection of a catalyst, in industry, is based on catalytic activity. The catalytic activity can be calculated basically according to the following formula: The activity of a catalyst: weight of alkenyl acetates (production space time) PET = produced (g) volume (L) of catalyst x sampling time (h) The selectivity of a catalyst selectivity for C2 = moles of vinyl acetate produced moles of vinyl acetate produced 4-1 / 2 moles of C02 produced selectivity for C3 = moles of allyl acetate produced moles of allyl acetate produced + 1/3 moles of C02 produced As the surface area of the metals in the catalyst prepared according to the present invention is greater compared to that of the catalyst prepared through reducing processes using liquid reducing agents, then the efficiency of the catalyst in the present invention is So much more. From the evaluation of the catalytic activity it is confirmed that when the catalyst is used to produce alkenyl acetates, the catalyst prepared in the present invention not only provides greater activity of the total reaction of the olefins, acetic acid and oxygen, but also that it also prolongs his own life. That is, compared to the conventional catalyst, the catalyst of the present invention is capable of producing more alkenyl acetates per unit volume of catalyst in the reactor and per unit time, when the conditions of the synthesis reaction (such as pressure, temperature and oxygen concentration) remain constant. Furthermore, if the productive performance remains constant, not only the reaction temperature can be lowered, but also the selectivity of the reaction can be higher, which leads to lower production of carbon dioxide and less product loss during the elimination of dioxide. carbon, and thus the unit consumption of raw materials will be lower. The present invention will be described further with reference to the following Examples and Comparative Examples, but the scope of the present invention is not limited in any way.

E j e pl o 1 The carrier used in this example was a porous carrier of alumina / s i i ce, with an external diameter of 5 mm and was obtained from SUD-CHEMIE AG. This carrier had a surface area of 100 to 120 m2 / g, a pore volume of 0.7 to 0.9 ml / g and a bulk density of 600 g / L. The catalyst for the support of metallic components was prepared according to the following steps: Step 1): An aqueous solution of Na2PdCl4 with a weight of 2.2 kg, containing 15% by weight of palladium, was added to an aqueous solution of HAuCl4. The mixture was then diluted with deionized water to a total volume of 37.2 L. 100 L of alumina carrier was placed in a tank for impregnation, with a speed of 24 turns per minute. The mixture was added quickly in 10 minutes.

Step 2): Hot air was passed through the carrier, to dry it, until the remaining moisture was less than 4%. The temperature of the hot air was less than 120 ° C.

Step 3): A solution of NaOH at 28 or by weight was added to the dry catalyst, with a weight of 160% that of the amount absorbed by the carrier (approximately 60 kg). The immersion time was more than 20 hours. Palladium and gold, originally in the soluble chloride state, were transformed into palladium and gold in an insoluble hydroxide state.

Step 4): The catalyst carrier, impregnated, was placed, after drying, in a reactor for reduction, with controlled temperature at 165 ° C and a pressure adjusted to 2 kg / cm2 (gauge pressure). The reducing gases were passed through the reactor with a flow velocity of 15 cm / s, where the composition of the reducing gases was hydrogen: nitrogen = 1: 3. Palladium and gold in the hydroxide state were reduced to palladium and gold in the metallic state.

Step 5): The above catalyst was washed to remove the chloride ions with the amount of 15 to 16 liters of deionized water per liter of catalyst, until the catalyst was free of chloride ions.

Step 6): The catalyst carrier was dried as in step 2).

Step 7): An adequate amount of potassium acetate was added to the dry catalyst carrier such that each liter of the catalyst contained a weight of 30 g of potassium acetate.

Step 8): The catalyst carrier was dried as in step 2).

After the previous steps, a catalyst containing 3.3 g / L of palladium, 1.5 g / L of gold and 30 g / L of potassium acetate was obtained, in which all the palladium and gold were well distributed over the surface of the carrier and the surface area of the metals was determined, the results are listed in Table 1. 900 ml of the catalyst thus obtained was charged to a reaction tube having an internal diameter of 20 mm and a length of 2.0 m. Under a pressure of 8 kg / cm2 (gauge pressure) at the inlet of the reactor, the gaseous reaction mixture was introduced to the reactor at a temperature of 140 ° C. The gas mixture was composed of 41% by volume of ethylene, 43% by volume of nitrogen gas, 10% by volume of acetic acid and 6% by volume of oxygen. Although the composition at the exit was analyzed at a defined time, the activity and selectivity of the catalyst were calculated. The results are listed in Table 1. When the activity and selectivity of the catalyst were evaluated, the crude product leaving the reactor was cooled with chilled water, and the composition was analyzed by Shimadzu Gas Chromatography. The flow velocity of the gases was determined through a Shinagawa Dry Gas Meter and the surface area of the metals was determined in accordance with the Chemisorp Method as in ASTM D3908.

E empl o 2 This is a repeat of Example 1, except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg, containing 18 wt.% Of palladium, and an aqueous solution of HAuCl 4 with a weight of 0.5 kg containing 36% in gold weight. As such a catalyst was obtained which contained 4.0 g / L of palladium, 1.8 g / L of gold and 30 g / L of potassium acetate, wherein all the palladium and gold were well distributed over the surface of the carrier. This catalyst was evaluated through the same methods as in the Axis * pio 1, and the results are listed in Table 1.

Example 3 This is a repeat of Example 1 except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg, containing 22.5 wt% of palladium, and an aqueous solution of HAuCl with a weight of 0.5 kg containing 45 wt% were prepared. of gold. As such, a catalyst containing 5.0 g / L of palladium, 2.25 g / L of gold and 30 g / L of potassium acetate was obtained, wherein all the palladium and gold were well distributed over the surface of the carrier. This catalyst was evaluated by the same methods as in Example 1, and the results are listed in Table 1.

E empl o 4 This is a repeat of Example 1 except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg, containing 30 wt.% Palladium and an aqueous solution of HAuCl 4 with a weight of 0.5 kg, containing 60 wt. of gold. As such, a catalyst containing 6.6 g / L of palladium, 3.0 g / L of gold and 30 g / L of potassium acetate was obtained, wherein all the palladium and gold were well distributed over the surface of the carrier. This catalyst was evaluated by the same methods as in Example 1, and the results are listed in Table 1.

Comparative Example 1 This is a repeat of Example 1, wherein the catalyst was prepared with an aqueous solution of Na2PdCl with a weight of 2.2 kg, containing 15% by weight of palladium and an aqueous solution of HAuCl with a weight of 0.5 kg, containing 30% by weight of gold, except that step 4) was altered as follows: the impregnated porous carrier, 5 mm, after step 3) was poured into 50 L of an aqueous solution containing 5% N2H4 for 4 hours , so that palladium and gold in the hydroxide state, deposited on the carrier, were reduced to palladium and gold in the metallic state. The same subsequent procedures of Example 1 were followed, and the carrier was washed, potassium acetate was added and the catalyst carrier was dried. This catalyst was evaluated by i-S same methods as in Example 1, and the results are listed in Table 1.

Comparative Example 2 This is a repeat of the catalyst preparation, as in Comparative Example 1, except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg containing 18 wt.% Palladium, and an aqueous solution of HAuCl with a weight were prepared of 0.5 kg containing 36% by weight of gold. This catalyst was evaluated by the same methods as in Example 1, and the results are listed in Table 1.

Comparative Example 3 This is a repeat of the catalyst preparation, as in Comparative Example 1, except that an aqueous Na 2 PdCl 4 solution weighing 2.2 kg, containing 22.5 wt% palladium, and an aqueous solution of HAuCl 4 were prepared with a weight of 0.5 kg containing 45% by weight of gold. This catalyst was evaluated by the same methods as those of Example 1, and the results are listed in Table 1.

Comparative Example 4 This is a repeat of the catalyst preparation, as in Comparative Example 1, except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg, containing 30 wt.% Of palladium, and an aqueous solution of HAuCl with a weight of 0.5 kg containing 60% by weight of gold. This catalyst was evaluated by the same methods as those of Example 1, and the results are listed in Table 1.

E j emp lo 5 This is a repeat of the catalyst preparation, as in Comparative Example 1, except that a solution of Na2PdCl with a weight of 2.2 kg, containing 15 wt.% Of palladium, and an aqueous solution of CuCl2 with a weight were prepared. of 0.5 kg, which contained 14.6% by weight of copper. After the previous steps, a catalyst containing 3.3 g / L of palladium, 0.34 g / L of copper and 30 g / L of potassium acetate was obtained, in which all the palladium and copper were well distributed over the surface of the palladium. po rt ador 600 ml of the catalyst thus obtained was charged to a reaction tube having an internal diameter of 20 mm and a length of 2.0 m. Under a pressure of 7.0 kg / cm2 (gauge pressure) at the inlet of the reactor, the reaction gas mixture was introduced into the reactor at a temperature of 148 ° C. The gas mixture was composed of 29% by volume of propylene, 44% by volume of nitrogen gas, 6.7% by volume of acetic acid, 13.5% by volume of vapor and 6.5% by volume of oxygen. According to the same methods as those of Example 1, while the composition at the outlet was analyzed at a defined time, the activity and selectivity of the catalyst were calculated, and the surface area of the metals was determined. The results are listed in Table 1.

Example 1 o_ This is a repeat of the catalyst preparation, as in Example 1, except that an aqueous Na 2 PdCl 4 solution weighing 2.2 kg was prepared, containing 15 wt% of palladium and an aqueous solution of CuCl 2 with a weight of 0.5 kg containing 6.0% by weight of copper. This catalyst was evaluated by the same methods as those of Example 5, and the results are listed in Table 1.

Example 7 This is a repeat of the catalyst preparation, as in Example 1, except that an aqueous Na2PdCl4 solution weighing 2.2 kg was prepared, containing 22.5% * by weight of palladium and an aqueous solution of CuCl2 with a weight of 0.5 kg containing 14.6% by weight of copper. This catalyst was evaluated by the same methods as those of Example 5, and the results are listed in Table 1.

Comparative Example 5 This is a repeat of the catalyst preparation, such as that of Comparative Example 1, except that an aqueous solution of Na 2 PdCl 4 with a weight of 2.2 kg, containing 15 wt.% Of palladium, and an aqueous solution of CuCl 2 with a weight of 0.5 kg containing 14.6% by weight of copper. This catalyst was evaluated by the same methods as those of Example 5, and the results are listed in Table 1.

Comparative Example 6 This is a repeat of the catalyst preparation, as in Comparative Example 1, except that an aqueous Na2PdCl solution with a weight of 2.2 kg, containing 15 wt.% Of palladium, and an aqueous solution of CuCl2 with an weight of 0.5 kg containing 6.0% by weight of copper. This catalyst was evaluated by the same methods as those of Example 5, and the results are listed in Table 1.

Comparative Example 7 This is a repeat of the catalyst preparation, such as that of Comparative Example 1, except that an aqueous Na 2 PdCl solution weighing 2.2 kg, containing 22.5 wt% palladium, and an aqueous solution of CuCl 2 with an weight of 0.5 kg containing 14.6% by weight of copper. This catalyst was evaluated by the same methods as those of Example 5, and the results are listed in Table 1.

Comparative Example This is a repetition of Example 1, except that instead of hydrogen ethylene was used as the gaseous reducing agent, in the process of reducing ion. This catalyst was evaluated by the same methods as those of Example 1, and the results are listed in Table 1.

Table 1 Table 1 (Continued) It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

1. A catalyst preparation process, characterized in that it comprises (a) impregnating above the surface of a catalyst carrier, with a solution containing a noble metal in the oxidation state, as the main catalyst, and a metal in the oxidation state , as the promoter of catalysis, reduce metals from the oxidation state to the metallic state, in gas phase, with a gaseous reducing agent, at a temperature that is in the range of 100 to 300 ° C, and a pressure that is find in the range of 0 to 5 kg / cm2 (gauge pressure); (b) impregnating the reduced catalyst with a solution of an alkaline or alkaline earth metal compound, and then drying the catalyst.

2. The process according to claim 1, characterized in that the noble metal is palladium.

The process according to the rei indication 1, characterized in that the metals used as the promoter of the catalysis are gold, copper, molybdenum, cadmium and magnesium.

4. The process according to claim 1, characterized in that the alkali metal or alkaline earth metal compound is the hydroxides, acetates, nitrates and bicarbonates of potassium, sodium, cesium, magnesium and barium.

5. The process according to claim 1, characterized in that the catalyst carrier is alumina, silica gel, silica, activated carbon, silicon carbide, diatomaceous earth and pumice.

6. The process according to claim 1, characterized in that the gaseous reducing agent is hydrogen.

7. A catalyst prepared by the process according to claim 1, characterized in that it is convenient to produce alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in vapor phase.

8. The catalyst according to claim 7, characterized in that the olefins are ethylene, propylene and isobutylene.

9. The catalyst according to claim 7, characterized in that the alkenyl acetate is vinyl acetate.

10. The catalyst according to the rei indication 7, characterized in that the alkenyl acetate is the allyl acetate. SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of a catalyst comprising a noble metal, and a metal as the promoter of the catalysis, in combination with an alkaline or alkaline earth metal compound, supported on the external surface of a carrier. The preparation process comprises impregnating the carrier with a solution containing a noble metal in the oxidation state, as the main catalyst, and a metal in the oxidation state as the promoter of the catalysis, reducing metals in the oxidation state to the metallic state , in gaseous phase, with a gaseous reducing agent, under certain temperature, pressure and concentration of the gas, then impregnate the reduced carrier with a solution of an alkaline or alkaline earth metal compound. The catalyst supporting the metal components, prepared by the process according to the present invention, has a high surface area and exhibits high catalytic activity, which leads to an increase in the catalytic ficiency and life of this heterogeneous catalyst. The catalyst prepared in the present invention is convenient for producing alkenyl acetates through the reaction of olefins, acetic acid and oxygen, in the vapor phase.