Hydrogenation catalyst and hydrogenation process

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a multi-component catalyst for the hydrogenation of highly unsaturated compounds comprising Pd and a group selected from modifiers on supports having particular characteristics, and with a hydrogenation process of unsaturated hydrocarbons, and more in particular, selective hydrogenation of highly unsaturated hydrocarbons, such as acetylenes. More particularly, the invention relates to the selective hydrogenation of acetylenic compounds in C2-C4 mixed olefin streams.

Related information

Nickel and palladium catalysts with support have been used for various hydrogenation processes for a considerable period of time. Such processes include the selective hydrogenation of acetylenic compounds and dienes in various mixed olefin and gasoline streams, and the hydrogenation of benzene.

German Patent 2,412,191 describes the purification of 1,3-butadiene and isoprene streams by selective hydrogenation of acetylenic compounds using finely dispersed catalyst or supported catalyst. The preferred catalyst metal is either a noble metal, such as Pd, or a non-noble metal, such as Co, Fe or Mo. The refined claim is that the use of cyclopentadiene improves the selectivity of 1,3-butadiene, either with noble or non-noble catalyst.

IJMR: 208,815 hsd

The fact that supported Pd catalysts are unstable for the selective hydrogenation of vinyl acetylene has been well documented, due to the formation of complex vinyl acetylene compounds with Pd. The compounds

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Pd complexes are soluble in the hydrocarbon stream. It has been found that the addition of piata to the Pd catalyst causes stabilization of catalyst deactivation caused by the loss of Pd metal, and an improvement in the selectivity of desired olefin product. See ML Derrien and others, "Studies in Surface Science and Catalvsis." Vol. 27, page 613 (1986) and Elsvier and K. James Sasaki, 'Petrochemicals and Gas Processing. 113 PTQ Autumn, 1997.

US Patent No. 4,533,779 describes palladium catalyst supported on taies such as alumina supports (1 to 100 m²/ g) for the selective hydrogenation of acetylenic compounds. The alumina used in the examples had a surface area of ​​70 m²/ g, a total pore volume of 0.6 cc / g and an average pore diameter of 200 Â. The deposit of Pd and Au was carried out in two sequential stages. The impregnation of the palladium compound on alumina was carried out using the technique of absorption of an organo palladium compound (acetylacetonate) in non-polar organic solvent on alumina. Palladium and gold contents in the catalysts were in the range of 0.03 to 1% by weight and 0.003 to 0.3% by weight, respectively.

US Patent No. 4,762,956 describes a new catalyst and process for the hydrogenation of impurities of acetylene and dienes in an olefin feed. The catalyst is a palladium catalyst supported in substantially crystalline alpha alumina, whose average pore radius is 200-2,000 Â, with at least 80% pores with a pore radius within the range of 100 to 3,000 Â. The active palladium metal surface was less than 50 m²/ g, with an average palladium particle size of at least 25 Â. Palladium impregnation was carried out by spraying aqueous palladium chloride solution on alumina, through an atomizer, followed by drying at 80 ° C.

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hydrogenation using a Pd catalyst sustained on a support such as alumina, but modified with alkaline iodide such as potassium iodide, to reduce the formation of heavy products during the selective hydrogenation of diolefins and / or acetylenic compounds in mixed hydrocarbon streams.

US Patent No. 5,877,363 describes the process for the selective hydrogenation of acetylenic impurities and isomerization of 1,2butadiene to 1,3-butadiene in mixed currents of C-rich olefins.₄, using Pt catalyst, Pd, etc., sustained.

European Patent No. 0 567 198 describes Pd-Cu-K / AI catalyst₂C&gt; 3 for the hydrogenation of alquinas and dienes. The preferred catalyst composition is 0.2% Pd, 0.3% Cu and 0.41% K. The preferred alumina support is yAI2-O3, which is 100-250 m²/ g of surface area and 0.4-0.7 cm³/ g pore volume.

U.S. Patent Nos. 4,644,088 and 4,658,080 describe acetylene removal processes. The catalyst is a multi-component catalyst comprising at least Fe and Ni, other elements of Group 8, IB, HB, IVB, VIB and VI IB of the Periodic Table, an alkaline earth metal and an alkali metal. The catalyst was prepared by mixing dry ZnFe powders₂O4, BaCO₃ and NiCO₃, followed by kneading the dry mixture with aqueous NaOH solution and forming the appropriate shaped and sized pellets, which were dried. The catalyst comprised a mixture of metal oxides, salts and hydroxides, as such was prepared. The catalyst activator work seems to be composed mainly of metals and metal oxides. Aluminum oxide is not part of this catalyst. The acetylenes are removed by contacting the feeds with catalyst in the vapor phase, at a temperature range from 250 ° to 900 ° C.

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According to V. Rives et al., The addition of Zn to the Ni-AI Cr oxide catalyst for the hydrogenation of acetylene in a mixed olefin stream hinders the formation of coke on the catalyst surface, and the higher selectivity to ethylene it is achieved for an atomic Zn / Ni ratio of 4 (Applied Clay Science 13 (1998) 363-379).

A. Sarkany published a document on Pd-Ag and Pd catalysts of the egg shell type supported on alpha alumina, for the hydrogenation of 1,3-butadiene (Applied Catalysis: General 175 (1998) 245-253). The deposit of heavy hydrocarbons of low reactivity on the surface of the catalyst causes both the deactivation of the catalyst and the overhydrogenation of paraffinic products.

H. Uygur and others published a document (J. Chem. Eng. Japan, Vol. 31, No. 2, 178 (1998)) in relation to the selective hydrogenation of liquid phase of methylacetylene and propadiene (MAPD) ​​in a mixed stream C₃. They found that the conversion of MAPD on 0.3% Pd catalyst decreases as the hydrogenation temperature increases. SD Jackson et al. (App. Catalysis A: General 134 (1996) 91-99) found that the adsorption of phenyl acetylene increases with the adsorption temperature during their study of the liquid phase hydrogenation of phenyl acetylene and styrene on a catalyst of Palladium held in carbon. NRM Sassen and others (Faraday Discuss. Chem. Soc., 89 (1998), 331-320) found that the species of ethylidene adsorbed on Pd (111) increases as the temperature rises from -20 ° C to 0 ° C. We find that this is also true for the selective hydrogenation of acetylenic compounds C₃ and C₄ in a mixed stream of crude butadiene on sustained Pd-Ag catalyst. This apparently strange behavior is the result of the combined effect of the very low activation energy (&lt;0.5 kcal / mol) of selective hydrogenation, higher hydrogen solubility

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in the feed stream at a lower temperature and temperature dependence of the adsorption of acetylenic compounds per palladium surface in a ternary phase reaction system of gas, liquid and solid catalyst. In other words, the concentration of hydrogen in the liquid phase has more influence on the index of selective hydrogenation of acetylenic compounds than the effect of the apparent activation energy.

SUMMARY OF THE INVENTION

The present invention includes a sustained catalyst comprising (1) Pd or a Group 8 metal comprising Pd and another Group 8 metal, preferably, a Group 8 metal selected from Pt, Ir, Ru, Co or Ni, and (2) at least two metals selected from Ag, Zn or Bi, preferably Ag and at least one from Zn or Bi. Optionally, the catalyst may contain K. The content of K in the catalyst will normally be less than 0.5% by weight.

The hydrogenation process of unsaturated compounds by contacting hydrocarbon streams containing small amounts of acetylenic compounds, with the catalyst of the invention in various arrangements and configurations, is also part of the present invention.

Preferred supports are highly porous, which have an average pore diameter greater than about 180 Â, no narrower pore than 35 Â, a total pore volume greater than about 0.65 cc / g and preferably, less than about 100 m²/ g BET surface area.

DETAILED DESCRIPTION OF THE INVENTION

This invention comprises an improved catalyst and a hydrocarbon hydrogenation process using the catalyst. In particular, the hydrogenation process is related to the hydrogenation of multi-unsaturated compounds, such as acetylenic compounds and dienes to mono and diunsaturated equivalent products or saturated products, depending on the purpose of the

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objective process, and the hydrogenation of aromatic compound such as benzene, to cyclic compound. Hydrogenation can be carried out in the vapor phase, in the liquid phase and in the existence of a mixed phase of steam and liquid. Hydrogenation can be carried out in any of a fixed bed reactor, a drip bed reactor, a catalytic distillation reactor or any combination thereof in the presence or absence of solvent. Examples of the preferred solvent are tetrahydrofuran, benzene, toluene, etc.

This invention is particularly useful in the removal of acetylenic compounds and dienes in C2-C-12 organic compounds by selective hydrogenation to mono or diunsaturated or saturated organic compounds. Examples of such feed streams are C2, C3, C4, C5 fractions fractionated by steam, or a mixed stream of C2-C6 and gasoline boiling range fuel.

The improved catalyst described in this invention is a multi-component catalyst supported on highly porous supports such as alumina, silica, silica-alumina, coal, etc., which have a total pore volume of at least 0.65 cm³/ g, and the average pore diameter of more than 180 Â. The preferred support is alumina, whose BET surface area is in the range of from 10 to 100 m²/ g, preferably, 20 to 70 m²/ g. The physical forms of alumina can be spheres, pellets, granules, or extruded products whose size is in the range of 1/32 to% inches (0.07 to 0.63 cm). Shaped alumina support shall have the bulk density (ABD) of less than 0.7 g / cm³, but not more than about 0.8 g / cm³. The alumina is a transition alumina that has mixed crystalline forms of α, k, θ, δ, ρ, η, γ and χ, according to the calcination temperature and the crystalline structure of the aluminum monohydrate raw material. Alumines composed mostly of crystalline form γ ο χ are not preferred supports. For the preparation of the

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Preferred alumina, the alumina shaped raw materials, such as alumina gel or aluminum monohydrate, are calcined at a temperature in a range of from about 650 ° C to 1,250 ° C. The final calcination temperature is determined by the physical properties of the alumina support to obtain the best catalyst performance for the specific hydrogenation process.

The preferred alumina described in this invention can be prepared by a number of techniques well known to those skilled in the art of alumina preparation. One of the preferred aluminas described in this invention can be prepared by so-called oil drip gelation techniques. Examples of prior art are described in US Patents No. 2,620,314; 4,273,735 and 4,179,408. Spherical shaped alumina is prepared from aluminum hydroxychloride sol prepared by digestion of aluminum metal in aqueous hydrochloric acid solution. Spherical-shaped alumina sol materials, produced in the form of drops, are gelled in a basic liquid oil phase, followed by maturation, washing, drying and calcination to the transition state aluminas at various temperatures, depending on the property. desired alumina. Alternatively, the preferred spherical shaped alumina can also be prepared by the oil dripping gelation technique using the boehmite alumina soles or pseudoboehmite. The alumina soles are prepared by dispersing aluminas of suitable boehmite, pseudoboehmite or mixtures of boehmite and pseudoboehmite obtained by hydrolyzing aluminum alkoxides, and then crystallization or reaction of the solution of sodium aluminate with an aluminum sai solution, such as aluminum sulfate or aluminum nitrate, and then crystallization. Several scattered boehmite aluminas or scattered boehmite alumina soles are available in the market. One of the

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Suppliers is Condea. For the preparation whose physical properties are described in this invention, as raw materials Dispersai HP 14/2, Dispai 11N7-80, Dispai 23N4-20, Disperai HP 14, Deperal 40, Pural 200, Pural 100, Pural NG, can be used. etc., or mixtures thereof. Other materials for the preparation of the preferred alumina support described in this invention, due to a surface area too high, a pore diameter too narrow and a pore volume too small. These materials produce the similar alûmines described in US Patents 4,493,906 and 4,440,956. The preferred alumina in various forms of extruded tablets or products can also be prepared by extrusion of the preferred boehmite or pseudoboehmite aluminas discussed above, and calcination at an elevated temperature from about 650 ° C to about 1,250 ° C. Optionally, various structured packaged materials made of metals or ceramic materials for distillation column can be used as the support.

The content of K in the catalyst will normally be less than 0.5% by weight. The metal content in the catalyst is Pd, preferably, in a range of 0.005 to 1% by weight, more preferably, from 0.01% to 0.3% by weight; Nor, preferably in the range of 0.0 to 15% by weight, more preferably, from 0 to 10% by weight; Ag, preferably in the range of 0.002 to 20% by weight, more preferably, 0.005 to 5% by weight; Zn, preferably in the range of 0 to 5% by weight, more preferably, 0.002 to 1% by weight; and Bi, preferably in the range of 0 to 5% by weight, more preferably, 0.01 to 3% by weight.

To deposit desired elements in a support, various techniques such as impregnation in solution using rotary evaporator, incipient pore impregnation, spray coating impregnation using

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atomizer, steam tank technique, co-precipitation techniques, etc. Preferred techniques in this invention are spray coating impregnation and incipient pore impregnation. Especially, spray coating impregnation is the most preferred technique in this invention.

According to the objective of the specific hydrogenation reaction that determines what elements and how much of them are needed in the catalyst, a simple impregnation or a double impregnation is carried out. If Pd, Ag and Zn are necessary elements, a mixed solution of compounds Pd, Ag and Zn in water or organic solvent is prepared. The solution is sprayed on the rolling support, such as aluminum alumina in a rotating impregnator, followed by drying with hot gas, such as air or nitrogen as a temperature in a range of 60 ° C to 300 ° C. The dried impregnation product is usually calcined at a temperature of from about 250 ° C to 600 ° C in air. If double impregnation is necessary for the best behavior of the catalyst, the first impregnation of a suitable support is carried out by impregnation of incipient pore, with an aqueous solution of a compound Zn, a mixed solution of compounds Ag and Zn or of compounds Pd, Ag and Zn, according to the specific behavior objective of the catalyst. The impregnation product is dried at a temperature of from 60 ° C to 300 ° C, followed by calcination at a temperature of 250 ° C to 600 ° C. The second impregnation is carried out by spray coating impregnation with the second mixed solution of compounds Pd and Ag or Pd, Ag and Zn on the first impregnation product, with an atomizer, followed by drying and calcining at a suitable temperature as described above. For the most selective hydrogenation reactions, as well as the removal of acetylenic compounds in various mixed currents of olefins or dienes, the penetration of Pd from the external geometrical surface of the supports into the supports meets a

<img file="AR036628A1_D0009.tif" />

important function in the determination of selectivity and catalyst stability. Pd penetration of less than 0.08 mm, preferably less than about 0.06 mm, is highly desirable. This objective can be achieved by creating a fine liquid mist of the impregnation solution suspended in a gaseous phase, using a compressed gas atomizer. In addition, the volume of the liquid impregnation solution for a given amount of a support is important. The desired volume of the solution is less than about 85% by volume, preferably, less than 65% by volume of the total pore volume of the support.

When Bi is one of the desired components of the catalyst, the catalyst preparation can be carried out in one or two stages. For simple stage impregnation, the impregnation of a mixed solution of compounds Pd, Zn, Ag and Bi by a support is carried out either by means of the spray coating technique on support that rolls within a rotating impregnator, or the incipient pore impregnation technique, followed by drying and calcination as described above. If two-stage impregnation is desired, in the first stage a solution of a Bi compound or a mixed solution of Bi and Zn compounds is used, either for the incipient pore impregnation technique or for the spray coating technique, followed by drying and calcining at appropriate temperatures, described above. Another alternative technique that incorporates Bi or Bi and Zn in alumina support is the impregnation of a solution of compound Bi or a mixed solution of compounds Bi and Zn by uncalcined alumina, followed by drying and calcining of the impregnation product at a temperature in a range from 650 ° C to 1,300 ° C. The second impregnation of a mixed solution of compounds Pd, Ag and Zn, or of compounds Pd, Ag, Zn and Bi by the product of the first impregnation stage is carried out either by

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spraying or by impregnation drying and calcination, as impregnation of coating by incipient is described, followed again by the above.

For the preparation of catalyst of multiple components containing Zn or both Zn corno Bi, Zn, or both Zn corno Bi can be incorporated into the oil dripping gelation technique for the preparation of alumina support. The alumina support can be prepared by dripping alumina sol containing dissolved Zn compound, or both Zn corno Bi compound, in the basic oil phase to form gel, followed by ripening, washing, drying and calcining at a temperature in the range of 650 at 1,250 ° C. Optionally, the alumina support can be prepared by impregnating a solution of compound Zn or Bi, or a mixed solution of compounds Zn and Bi, by the alumina powders having the physical characteristics of the preferred supports described above. Suitable raw materials for the preparation of such alumina powders are boehmite powders and pseudoboehmite powders described above. The raw materials are calcined at temperatures from 350 ° C to approximately 750 ° C, before impregnation. The impregnation products are calcined at a temperature from about 250 ° C to 600 ° C, and then a desired size of extruded products or pellets is formed. Finally, the shaped materials are calcined in air at an elevated temperature from about 650 ° C to 1,300 ° C. The mixed solution containing Pd and Ag compounds, or Pd, Ag and Zn compounds, is impregnated on the thus prepared alumina support, using one of the impregnation techniques described above, followed by drying and calcination.

The hydrogenation of unsaturated organic compounds is carried out with one or more catalysts. For selective hydrogenation, one, two or more catalysts can be used to improve the yield of desired products.

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For example, in the complete or almost complete conversion of vinyl acetylBr-ethif acetylene and methyl acetylene in a stream of butadiene with steam fractionation, two or more catalysts, whose compositions and metal loading are different, can be used to obtain the product of Highest quality with the best result desirable from an economic point of view. The catalysts can be loaded in a reactor alone or in two reactors. The higher activity catalyst is charged in front of the lower activity catalyst in a single reactor operation (catalytic or fixed bed distillation reactor operation), so that the feed stream is first passed through the zone of higher activity catalyst. The hydrogen feed stream can be fed to the feed hydrocarbon stream at a single point before entering the catalytic reaction zone, or it can be fed into two or more different positions along the reactor, to obtain the result more desirable, because usually two catalysts of different activity have different optimal ratios of hydrogen to acetylenic compounds in the feed at a given condition of concentration of a particular acetylenic compound, temperature, pressure and hydrocarbon flow rate. If two reactors are used, the higher activity catalyst is loaded into the first reactor.

Hydrogenation of catalytic distillation is the preferred mode for the selective hydrogenation of acetylenic compounds in various mixed streams, to obtain the best selectivity and long life of the catalyst in the absence or presence of solvent. In the hydrogenation of catalytic distillation, the polymer precursors and heavier polymers are washed and expelled continuously by the liquid phase, and removed as a part of the lower stream, keeping the catalyst surface cleaner than in the bed operation permanent. Usually, the selectivity of desired products is better than

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Higher concentrations of acetylenic compounds in the catalytic reaction zone by the appropriate operation of the distillation column reactor, which can be achieved in the case of the fixed bed operation. If solvent is used, the catalytic distillation column can be operated in two ways. The distillation column can be operated in the total internal reflux mode for the solvent, or the solvent can be fed to the upper section of the column over the catalytic reaction zone and removed as part of the lower current, according to the point boiling solvent. The solvent recovered from the lower stream is recycled back to a position on the catalyst zone of the catalytic distillation column.

Examples

Control Example 1

The commercial Pd-Ag catalyst of the egg shell type supported on alumina (G681 obtained from ICU) was used to remove acetylenic compounds in a stream of butadiene fractionated with crude vapor. 36 grams of the commercial catalyst (0.2% Pd-0.1% Ag on alumina) were mixed with 100 ml of 3 mm diameter glass balls and loaded into a vertical-mounted upstream stainless reactor (1 inch diameter x 20 inches long (2.53 cm diameter x 50.79 cm long) The catalyst ABD was 0.97 g / cc The average catalyst size is an extruded product of 2.5 mm diameter x 6 mm long. The catalyst was activated at 230 ° F (110 ° C) by passing 1 ml / min (measured at room temperature) of isobutane and 15 cc / min of hydrogen gas (10% by volume gas H₂ in He) under 200 psig (1.37 MPa) for two hours. The reactor was cooled to the predetermined temperature and then the reactor pressure was set at the predetermined pressure for hydrogenation. After closing both the hydrogen as horn

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the isobutane to the reactor, hydrocarbon &amp; w © ^ hydrogen feed was slowly introduced, while controlling the reactor temperature. Due to the exotherm of the hydrogenation reaction, there may be a sudden rise in temperature, if not careful, and the temperature at the beginning of the catalyst bed is lower than at the end of the catalyst bed.

Acetylenic impurities in a mixed C4 stream containing 570 ppm of tip, 6,550 ppm of vinyl acetylene, 1,497 ppm of ethyl acetylene, 55.47% of 1,3-butadiene, 0.22% of 1,2-butadiene and 15 , 41% of 1-butene, etc. by weight they were removed by carrying out selective hydrogenation on the activated G681 catalyst.

The improvements made in this invention over the prior art are the highest production rate, superior product stream quality, superior desired product performance and hydrogen savings.

Example 1

A spherical γ-alumina (2 mm in diameter) was used to prepare a suitable support described in this invention. Spherical γ-alumina is not a suitable support as such, due to the area of ​​surface too high and acidity. The physical properties of this alumina are listed in Table 1. The alumina was calcined at 1,150 ° C for 3 hours in air.

Table 1

ABC, g / cc

BET Single Point, m²/ g

BET Multiple Points, m²/ g

Area of ​​Poro Meso, m²/ g

Micro Pore Area, m²/ g

Cumulative Adsorption Surface Area, m²/ g Cumulative Desorption surface area, m²/ g

0,53

157,5

170,2

170,2

172,6

230,4

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at 493 À radio at P / PO = 0.9801 0.912 at 493 À radio at P / P0 = 0.9801 0.912

Pore ​​Volume of Cumulative Adsorption for pores (radius 20-300 Â) 0.852

Pore ​​Volume of Cumulative Desorption for pores (radius 17.5-300 Â) 0.930

Average Pore Diameter, Â 214.4

A mixed solution was prepared by dissolving 3.79 grams of Zn (NO₃)₂. 6H₂), 0.52 gram of AgNO₃ and 13 grams of Pd nitrate 10% by weight in aqueous HNO solution₃ at 10%, in 100 grams of deionized water. This mixed solution was sprayed on 300 grams of the calcined alumina using a compressed air atomizer and rotary impregnator, and dried with dry air at approximately 200 ° C for 1 hour. The dried product was calcined at 350 ° C for 2 hours. The calculated composition of this catalyst based on the amounts of chemicals used is 0.20% Pd / 0.11% Ag / 0.28% Zn, by weight.

36 grams of this catalyst (Pd / Ag / Zn / AI2O3) were mixed with 100 ml of 3 mm diameter glass beams, and charged to the same reactor used in Control Example 1. The catalyst was activated from the Following way. The reactor was purified with a flow of 200 cc / min of N₂ under 15 psig (0.10 MPa), it was slowly heated to 235 ° F (113 ° C), 100 cc / min of a gas flow H₂ it cut into gas flow N₂ and it stayed for an hour. After closing the gas N₂, the hydrogen gas flow was increased to 300 cc / min, and then the temperature rose to 550 ° F (288 ° C) for 2 hours. The reactor was cooled in hydrogen gas flow to the desired hydrogenation reaction temperature. The reactor was filled with nitrogen (150 cc / min) and set at a predetermined pressure for the hydrogenation reaction. The feed hydrocarbon and hydrogen feed gas were cut in the nitrogen stream slowly, z

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fjaivA while controlling the reactor temperature and slowly cutting off the flow of nitrogen gas. The hydrocarbon feed was the same feed used in Control Example 1. The results of Control Example 1 and Example 1 are cited in Table 2.

It results from the results cited in Table 2, that the three component catalyst (Pd / Ag / Zn) sustained on alumina has a superior performance over the conventional catalyst. The product quality in Example 1 is superior to the product in Control Example 1. The impurity of vinyl acetylene in the feed in Example 1 is completely removed. However, the recovery of 1,3-butadiene is better by more than 4% by weight. In general, it is very rare that a high activity catalyst has a higher yield of the desired product at the same or higher conversion, than that of the lower activity catalyst.

Example 2

The spherical γ-alumina used for the preparation of alumina support in Example 1 was calcined at 1,100 ° C for 3 hours in air.

A solution of bismuth nitrate was prepared, dissolving 4.31 grams of Bi (NO3) 3.6H₂Or in 285 ml of acidified deionized water with six drops of concentrated nitric acid solution, and the incipient pore impregnation with this solution was carried out in 300 grams of the above-mentioned calcined alumina. The impregnation product was turned cold for 10 minutes in a rotating impregnator, and then dried with hot air at approximately 200 ° C for 1 hour. The dried product was calcined at 450 ° C in air for 2 hours. A mixed solution was prepared by dissolving 3.79 grams of Zn (NO₃)₂.H₂Or, 0.52 grams of AgNC&gt; 3 ​​and 13.3 grams of 10% palladium nitrate solution by weight, in 10% nitric acid solution in 100 ml of deionized water. This mixed solution was sprayed on the mentioned calcined product

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previously, using compressed air atomizer and rotary impregnator, and then dried with hot air at approximately 200 ° C for 1 hour. The dried product was calcined at 350 ° C for 2 hours. The composition of this catalyst, calculated based on the amounts of chemicals used, is 0.20% Pd / 0.11% Ag / 0.27% Zn / 1.42% Bi by weight.

36 grams of this catalyst (Pd / Ag / Zn / Bi / AbOß) were mixed with 100 ml of 3 mm diameter glass beads, and charged to the same reactor used in Control Example 1. The catalyst was activated in the same way as in Example 1. The same hydrocarbon feed used in Control Example 1 and hydrogen stream were slowly cut in nitrogen stream, while the reactor temperature was controlled and the nitrogen gas flow was slowly cut off. The result is cited in Table 2.

Table 2

<td></td><td colspan="2">Control Example 1</td><td>Example 1</td><td>Example 2</td>

<td>Temperature (° F (° C)) *</td><td> 120 (49)</td><td> 110 (43)</td><td> 120 (49)</td><td> 120 (49)</td>

<td>Pressure (psig (MPa))</td><td> 108 (0,74)</td><td> 125 (0,86)</td><td> 108 (0,74)</td><td> 108 (0,74)</td>

<td>HC power WHSV</td><td> 4</td><td> 3</td><td> 4</td><td> 6,1</td>

<td>H index₂, foot²/ pound of HC</td><td> 1,34</td><td> 1,56</td><td> 1,34</td><td> 1,31</td>

<td colspan="5">Product composition (ppm) **</td>

<td>GOES</td><td> 85</td><td> 36</td><td> 0</td><td> 0</td>

<td>EZ</td><td> 278</td><td> 159</td><td> 91</td><td> 0</td>

<td>MA</td><td> 38</td><td> 18</td><td> 6</td><td> 1</td>

<td>Propadiene</td><td> 105</td><td> 80</td><td> 81</td><td> 110</td>

<td>1,2-BD</td><td> 1.322</td><td> 1.170</td><td> 1.212</td><td> 1.230</td>

<td>Recovery¹ 1,3-BD</td><td> 91,9</td><td> 89,6</td><td> 94,3</td><td> 92,5</td>

* Temperature at the end of the catalyst bed ** By weight

<td></td><td> 18, \</td>

<td>ν '</td><td>ί '' · ': / i? s (-vb - / Zi ^: XV ' ' 'Y-/. ; Weight% of 1,3-BD in product x 100</td>

<td>^F 1,3-BD recovery =</td><td>% by weight of 1,3-BD in feed</td>

The result clearly demonstrates the superior performance of the four component catalyst (Pd / Ag / Zn / Bi) sustained on alumina described in this invention, on the prior art. All C4 acetylenic impurities in the feed are completely removed, even when the feed rate is 50% higher. However, the recovery of 1,3-butadiene is superior to the prior art.