TW200906484A - Supported Pd/C catalyst and the preparation methodthereof - Google Patents

Abstract

A supported Pd/C catalyst, wherein the Pd supported to the active carbon carrier is present in the microcrystalline state, and the microcrystallines whose diameters are less than 2.5nm take up more than 80wt% of the total amount of the Pd microcrystallines. The preparation method of the supported Pd/C catalyst, wherein the solution for impregnating or spraying the active carbon carrier contains Pd compound and compound with formula I, wherein n, m or l is independently selected from the integers of 0 and 1~5, and R1, R2 or R3 is independently selected from the group consists of H, CH3, NH2, OH and COOH.

Description

200906484 IX. Description of the Invention: [Technical Field] The present invention relates to a metal palladium catalyst supported on activated carbon (hereinafter referred to as supported palladium/carbon catalyst) and a preparation method thereof, particularly for A supported type/carbon catalyst for purifying crude terephthalic acid by selective hydrogenation reaction and a preparation method thereof. [Prior Art] Supported palladium/carbon catalysts are widely used for selective hydrogenation of unsaturated organic compounds. In particular, the supported type/carbon catalyst is suitable for the purification of crude terephthalic acid, wherein some impurities in crude terephthalic acid such as p-carboxybenzaldehyde (4-CBA for short) are converted into other compounds by hydrogenation. Then, the P port of terephthalic acid can be separated and purified by crystallization. Since the epoch/carbon catalyst usually adopts a single active component, the improvement in the prior art mainly focuses on the structure of the carrier and the distribution of the metal Pd on the carrier, and the performance of the catalyst on the catalyst is very high. Great impact. Since the hydrofining reaction process of terephthalic acid is a first-order reaction, the reaction rate is fast, and it is difficult for the reactants to penetrate into the inside of the catalyst particles during the reaction to carry out the reaction, which makes the active components inside the particles ineffective. Therefore, in order to make full use of the noble metal, the palladium/carbon catalyst is usually made into an eggshell type, that is, the noble metal of the active component is mainly supported on the surface of the carrier. Since the hydrogenation reaction is carried out on the surface of the metal Pd, generally the same catalyst is supported for the metal Pd, the higher the dispersion of the metal in the catalyst and/or the higher the crystallite content of the metal pd supported in the catalyst and/or The better the thermal stability of the catalyst, the higher the activity of the catalyst and the longer the life of the product is 200,906,484. If a Pd-containing compound (such as sodium chloropalladate or palladium chloride) solution is directly loaded onto the activated carbon, a very thin, shiny metallic Pd layer will appear on the activated carbon surface. Mainly because the surface of the activated carbon contains a reducing group such as an aldehyde group and a free electron, they are extremely easy to reduce the Pd ion to a zero-valent metal Pd. Therefore, the catalyst thus obtained has a very low metal Pd dispersion. One way to overcome this problem is to convert the Pd ions in the impregnation liquid containing the Pd compound into an insoluble compound before the impregnation process. For example, the water-soluble compound of Pd is hydrolyzed to insoluble Pd(OH)2 or PdOH20 at room temperature, and then supported on activated carbon, followed by reduction with a reducing agent such as formaldehyde, sodium formate, glucose, formic acid or hydrogen. It can prevent the migration of Pd and grain growth. U.S. Patent No. 3,138,560 teaches the addition of hydrogen peroxide to the impregnation solution to hydrolyze the water-soluble compound of Pd to form an insoluble compound which is then impregnated. U.S. Patent No. 4,476,242 teaches the use of an organic solvent such as methanol or pyridine to prepare a Pd-containing impregnation solution which is said to be very effective in preventing Pd migration and grain growth. In addition, it has been reported that the conversion of the chloropalladic acid solution into a palladium-containing colloidal solution by adjusting the pH is said to prevent the reducing group on the surface of the active carbon from directly reducing the Pd ion to the zero-valent metal Pd. CN1698952A discloses the addition of nitrogen-containing polycarboxylic acids to a dipping solution for preparing a palladium/carbon catalyst. SUMMARY OF THE INVENTION 6 200906484 An object of the present invention is to provide a novel supported palladium/carbon catalysis. The metal Pd in the catalyst has a higher dispersion, a higher crystallite content and a better Thermal stability. When used in the hydrofinishing of crude terephthalic acid, the catalyst can provide high conversion of p-carboxybenzaldehyde (4_CBA). Another object of the month is to provide a method of preparing the supported batro/carbon catalyst. DETAILED DESCRIPTION OF THE INVENTION In a first aspect, the present invention provides a supported palladium/carbon catalyst in which a crystal form of a neon size which is supported by a carrier activity is present, and the 'eight medium particle size is less than 2.5 nanometers. The crystallites account for 80% by weight or more, preferably 85% by weight or more, more preferably 88% by weight or more, and most preferably 90% by weight or more based on the total amount of the crystallites. In the supported palladium/carbon catalyst of the present invention, the gold layer pd # iS ^ Π π 7 is mainly in the range of 5 to 5 ° / 〇, more preferably in the range of 0.2 to 3.5%, based on the catalyst Total weight. f from the preferred embodiment, the loading (iv) is enriched in the carrier active weight so that the palladium content of the palladium/carbon catalyst is the catalyst total zirconium G.5G ± iU () wt% of the case T, in the carrier The metal palladium in the layer of π and the surface of the activated carbon accounts for 30% by weight, preferably 40% by weight or more, more preferably 5% by weight or more of the total atomic weight of the layer. The metal palladium in the deep layer is 5% by weight or more, preferably 10% by weight or more, more preferably 15% or more, and most preferably 20% by weight or more, based on 10% by weight of the total weight in the layer. In the supported type/carbon catalyst of the present invention, the supported portion is highly dispersed in the carrier carbon 7 200906484 carbon surface, and the dispersion thereof is not less than 5%, preferably not less than 10%, more preferably not less than 15%, most It is preferably not less than 20%. At 500. 0: Down, bubbling through 25. (: caicining in a nitrogen stream of water: after 10 hours of catalyst, the average grain size of the supported palladium is not more than 10 nm, preferably not more than 8.0 nm, more preferably not more than 7 〇 nm, and most preferably not more than 6.0 nm. In a second aspect, the present invention provides a method of preparing a supported palladium/carbon catalyst. The method comprises the steps of: a) first washing the activated carbon with a mineral acid aqueous solution, and then washing it to neutral with water, and Drying the washed activated carbon to obtain an activated carbon support; b) impregnating or spraying the active supported carrier with an aqueous solution containing a Pd compound and an additive to support the Pd compound on the activated carbon support to obtain a catalyst precursor The molar ratio of the additive in the aqueous solution to the Pd in the pd compound is 0.01.1 to 2.0:1 'the additive is selected from the group consisting of the compound represented by the following formula I:

Ri-(CH2)„-CHC00H R2 - (CH2)m- CCOOH R3—(CH2)i -chcooh

Wherein 11, 11 and 1 are independently selected from the integers of deuterium, and &, R2 and R3 are independently selected from the group consisting of H, CH3, NH2, OH and COOH; the pH of the palladium solution is adjusted to 7 ± 3; And c) reducing the catalyst precursor with a reducing agent to obtain a supported palladium/carboniferous catalyst. According to a preferred embodiment, the above method further comprises aging the catalyst precursor at a temperature of from 80 ° C for 1 to 5 hours before the reduction of the 8 200906484 catalyst body. There is no particular limitation on the activated carbon used in the present invention. An example of activated carbon is a surface area of greater than 9 〇〇m 2 /g, and a particle size of 4-8 for a coconut shell activated carbon. The concentration of the aqueous solution of the mineral acid used in the method of the present invention may be in the range of 〇〇1 to 5 摩尔/ Within the range of liters, it is preferably in the range of 0_01 to 3 〇 mol/liter. Examples of the inorganic acid include, but are not limited to, hydrochloric acid, nitric acid, and phosphoric acid. The pickling time is not critical, but is preferably in the range of 〜 5 to 8 hours, more preferably in the range of 0.5 to 4 hours. The activated carbon is washed with the aqueous solution of the inorganic acid, washed with water until neutral, and then dried. Drying can usually be done at 8〇~丨5〇. Dry at a temperature of 0.5 to 10 hours, preferably 〇 5 to 6 hours. Examples of Pd compounds which can be used in the present invention include, but are not limited to, palladium halides, paiiadium acetate, palladium nitrate, chl 〇ropaiiadic acid, gas! Basic salts of chloropalladic acid, palladium ammino-complexes, and combinations thereof. Preferably the 'Pd compound is a gas or acid. The pH of the solution containing the pd compound and the additive is preferably in the range of 4 to 9. The concentration of the Pd compound in the solution in terms of pd is preferably in the range of 0.01 to 20% by weight, more preferably in the range of 0.1 to 10% by weight, most preferably in the range of 0.2 to 3.6% by weight.

The amount of the additive in the Pd solution may vary depending on the Pd compound used and the additive used in 200906484, but usually the molar ratio of the additive to the Pd compound in the solution is in the range of 〇.1:1 to 2:1. It is possible, and the molar ratio of the additive to the Pd in the Pd compound is preferably in the range of 〇.〇5:1 to 1.5:1, more preferably in the range of 1:1·1:1 to 1.0:1. Some examples of compounds of formula I useful in the present invention are as follows:

Rr (CH2)n-CHCOOH R2-(CH2)m-CCOOH

I R3-(CH2)i -chcooh Additive A Ri = R2= R3 = H n=m=l=〇Additive B Ri= R3 = Η ; R2=NH2 n = 5 ; m = 1-1 Additive C Ri= CH3 ; R2=R3 = H n=4 ; m=l=〇Additive D Ri=R2= H ; r3=oh n=m=3 ; 1=1 Additive E Ri=R3=H ; R2= COOH n=m= l = hydrazine additive F Ri = R3 = H; R2 = OH n = m = l = 〇 - Examples of reducing agents for reducing the catalyst precursor include, but are not limited to, formic acid, sodium formate ), formaldehyde, hydrazine hydrate, glucose, hydrogen, and combinations thereof. Preferably, the reducing agent is sodium formate or water & The amount of the reducing agent depends on the amount of the active component Pd, and is usually 丨1 to 1 times, preferably 2 to 5 times, the amount required for the reduction reaction theory. The reduction treatment of the catalyst body can be carried out according to procedures and conditions well known to those skilled in the art. For example, the reduction treatment can be carried out at a temperature of 〇 2 2 〇〇 t, preferably 〜 12 〇 C for 0.5 to 24 hours, preferably 1 to 10 hours, more preferably 10 200906484 for 1 to 4 hours. According to a preferred embodiment, the process for preparing a supported palladium/carbon catalyst of the present invention comprises the steps of: 1) washing the granulated or shaped activated carbon support with an aqueous acid solution for 5 to 8 hours, the acid of the aqueous acid solution The concentration is 〇.01~3 〇mol/liter, the acid is one selected from the group consisting of hydrochloric acid, tribasic acid and squaric acid; 2) the acid washed activated carbon carrier is washed with water to neutral, and then at 8 〇 150 150 Drying 〇·5~1 〇 hours under c conditions gives the treated activated carbon support; 3) immersing or spraying the treated activated carbon with an aqueous solution containing a water-soluble Pd compound and an additive of the following formula a carrier, wherein a pd compound is supported on the treated activated carbon support to obtain a catalyst precursor, wherein the content of the Pd compound in the aqueous solution is 〇丨~丨〇% by weight in terms of pd, and the additive and Pd are not The ear ratio is adjusted to 7 ± 3 ' in the range of 〇·〇 5 : 1 to 1.5 : 1

Ri-(CH2)„-CHCOOH R2-(CH2)m-CCOOH R3-(CH2)i -chcooh where n, m*丨 are independently any integer of o or i~5; and Rl4, R2 and R3 Independently selected from the group consisting of OH, hydrazine, CH3, nh2 and c〇〇H; 4) reducing the catalyst precursor obtained from step 3) from 0 to 8 (rc temperature aging 11 200906484 5) The agent is subjected to a reduction treatment to reduce Pd ions in the Pd compound to the metal pd' to obtain a catalyst product. Compared with the prior art, the present invention has an advantage in that the obtained catalyst has a metal P d dispersion of a car door and a high micro The crystal content and the catalyst have high activity and long service life. [Embodiment] Hereinafter, the present invention will be described by way of examples, without limiting the scope of the invention. In the examples, the following test methods are employed: (1) Metal-saturated Dispersity: The dispersion of metal palladium is determined by hydrogen peroxide titration using a chemical adsorption instrument. The dispersion is calculated according to the following formula: Dispersity = ((2xV suction xMPd) / (3x22400xW sample xCPd)) xl 〇 0% where: Indicates the amount of hydrogen adsorption of the sample,

Mpd indicates the atomic weight, W sample indicates the weight of the sample, and Cpd indicates the content of the sample. (2) Crystallite content: The term "crystallite content" as used in the present invention means the content of crystals having a particle diameter of less than 25 nm. The content of palladium in the catalyst was determined by X-ray spectrometer, and the particle size of the metal palladium crystallites was measured by π λ-ray diffraction (XRD), and then the crystallite content was calculated by the following formula: Microcrystalline content = (granules) Metal with a diameter less than 2 _ 5 nm, weight of the grain / total weight of the metal) X 100% 12 200906484 (3) Thermal stability: Determination of palladium grains of palladium/carbon catalyst by X-ray diffraction (XRD) Average particle size. The catalyst was then calcined at 500 ° C in a stream of nitrogen which was bubbled through 25 ° C of water for a few hours, and then the average particle size of the palladium grains was measured by a χ-ray diffractometer (xrd). The change in the average particle diameter of the palladium crystal grains after calcination and the average particle diameter of the palladium crystal grains before and after calcination indicates the thermal stability of the catalyst. The smaller the average particle size of the palladium grains after calcination, the better the thermal stability of the catalyst. The smaller the change in the average grain size of the grains after the calcination, the better the thermal stability of the catalyst. (4) Content of palladium in layers at different depths under the surface of the catalyst: Argon etching was performed on the surface of the catalyst. After etching to a certain depth, the content of palladium in the surface layer exposed to the surface of the catalyst can be determined by photoelectron energy (XPS) and Auger spectroscopy (AES). Example 1 100 g of coconut shell activated carbon passed through a 4-mesh sieve but retained on an 8-mesh sieve and having a surface area of 1,100 m 2 /g was washed with 200 ml of a 〇.4 mol/liter aqueous solution of nitric acid for 2 hours. After removing the acid solution, the activated carbon was washed with deionized water until neutral, and then dried at 120 ° C for 6 hours. 32 g of a palladium-containing aqueous solution containing 16% by weight of palladium was added, deionized water was added to 40 ml, and 2.16 g of a 10% by weight aqueous solution of the additive A was added thereto, and deionized water was added thereto to a volume of 6 ml of the solution. A 3% aqueous NaOH solution was added to adjust the pH of the palladium-containing solution to about 7. After the solution of the Pd solution was stabilized for 180 minutes, the above treated activated carbon was impregnated with the solution containing 13 200906484 for 3 hours to obtain a catalyst precursor. The catalyst precursor was aged at room temperature for 24 hours' and then impregnated at 2 (TC for 3 hours) in a reducing solution prepared from 20 g of a 5% by weight aqueous solution of hydrazine hydrate and 200 g of pure water. After removing the liquid by filtration, the solid was washed with neutral water to neutrality, and dried to obtain a catalyst product.Examples 2 to 24 Different Pd compounds and different additives were used to prepare a Pd-containing solution, and the rest were the same as in Example 1. The content of the pd compound, the Pd compound in the pd-containing solution (in pd), the specific additives, and the molar ratio of the additive to pd are listed in Table 1. Examples 25 to 30 The procedure of Example 1 was followed, but the selection was different. Additives to formulate 3 Pd / gluten solution (see Table 1 for specific additives), and spray the pd-containing solution on activated carbon to obtain a catalyst precursor, in addition to inorganic acid and inorganic acid as shown in Table 2. Concentration, pickling time, drying time, temperature, pH of the solution containing the additive and the Pd compound, reducing agent, reduction treatment temperature, and reduction treatment time. Comparative Example The preparation of the Pd-containing solution was carried out without adding an additive. In the same manner as in the examples, a catalyst prepared in each of the examples and the comparative examples was subjected to measurement of the degree of dispersion, crystallite content, heat enthalpy and different depths under the catalyst surface, and the evaluation was carried out under the following evaluation conditions. Catalyst, the results are shown in Table 3 and Table 4. Evaluation conditions of the catalyst: Catalyst dosage: 2.0 g 14 200906484

Amount of crude terephthalic acid: 30.0 g 4-CBA Amount: 1_〇g Reaction pressure: 70 Kg Hydrogen partial pressure: 5.0 Kg Reaction time: 1.0 hour Reaction temperature · 270〇C Add 4-CBA amount One remaining 4-CBA Amount of 4-CBA added x 00% 4-CBA conversion 15 200906484 Table 1 Example Pd compound additive Pd feed amount / activated carbon (% by weight) Additive / Pd (mole ratio) Example 1 Chloro 1 acid additive A 0.51 0.20 Example 2 Gas 1 acid additive A 0.51 0.30 Example 3 Chloric acid additive A 0.22 0.60 Example 4 Acetate additive A 0.08 1.50 Example 5 Chloro 1 acid additive B 0.51 0.20 Example 6 Chlorine acid Additive B 0.62 0.40 Example 7 Chloric acid additive B 0.51 0.60 Example 8 Palladium acetate additive B 3.55 0.80 Example 9 Chloro 1 acid additive C 0.51 0.20 Example 10 Chloro 1 acid additive C 0.51 0.40 Example 11 Acid additive C 0.51 0.60 Example 12 Palladium acetate additive C 0.15 1.00 Example 13 Chlorine acid additive D 0.51 0.20 Example 14 Chlorine acid additive D 0.41 0.40 Example 15 Gas acid additive D 0.51 0.60 Example 16 Palladium acetate additive D 0.51 0.80 Example 17 Chloro 1 acid additive E 0.51 0.20 Example 18 Chloro-acid additive E 1.00 0.40 Example 19 Chloro 1 acid additive E 0.51 0.60 Example 20 Acetic acid 1 bar Additive E 0.51 0.80 Example 21 Chloro 1 acid additive F 4.50 0.05 Example 22 Chloro 1 acid additive F 0.51 0.40 Example 23 Chloro 1 acid additive F 0.51 0.60 Example 24 Palladium acetate additive F 0.51 0.80 Example 25 Chlorine acid additive A 0.51 0.20 Example 26 Chloro palladium acid additive B 0.51 0.40 Example 27 Chloro palladium acid additive C 0.51 0.60 Example 28 Chlorine acid additive D 0.51 0.80 Example 29 Chloro palladium acid additive E 0.51 0.50 Example 30 Chloro 1 acid additive F 0.51 0.50 Comparative Example Chloroacid / 0.51 / 16 200906484 Table 2 Example 25 26 27 28 29 30 No. Condition Mineral Acid Type Salt Nitrite Shado Nitrate Shore Acid Acid Acid Inorganic Acid Concentration (Molar/L) 0.4 0.1 3 0.4 0.01 0.4 Pickling time (hours) 4 8 0.5 4 4 4 Drying temperature (°c) 150 120 120 80 120 120 Drying time (small) 1 6 6 10 6 6 pH of solution containing additive and Pd compound 9 7 6 7 4 10 Reducing agent type hydrogen citrate grape hydrate sodium aldehyde sodium glycoside reduction treatment temperature (°C) 50 80 120 200 120 80 Reduction treatment time (hours) 3 3 2 1 24 3 17 200906484 Table 3 Pd content (% by weight) in the catalyst of the example Dispersity (%) Microcrystalline content (%) Average grain size (nm) 500 °C Calcination Post-average grain size (nm) Particle size change before and after calcination % 4- CBA conversion (%) Example 1 0.50 20 90 3.5 5.9 69 99.5 Example 2 0.50 23 91 3.6 6.0 67 99.7 Example 3 0.20 29 90 3.4 5.3 56 89.2 Example 4 0.08 21 92 2.7 5.3 96 -- Example 5 0.50 20 90 3.5 5.9 69 99.4 Example 6 0.60 26 90 3.6 6.0 67 99.8 Example 7 0.50 28 93 3.8 5.8 53 99.5 Example 8 3.50 20 92 3.3 5.9 79 99.6 Example 9 0.50 20 91 2.9 5.7 97 99.6 Example 10 0.50 22 92 3.8 5.6 47 99.8 Example 11 0.49 25 90 3.6 5.8 61 99.7 Example 12 0.15 28 91 3.0 5.7 90 -- Example 13 0.50 20 90 3.6 5.9 64 99.5 Example 14 0.40 21 92 3.3 5.6 70 99.5 Example 15 0.50 26 91 3.4 5.8 71 99.8 Example 16 0.49 25 90 3.2 5.9 84 99.9 Example 17 0.50 30 94 3.6 6.0 67 99.7 Example 18 0.98 27 90 3.7 5.9 59 100 Example 19 0.50 27 91 3.4 5.8 71 99.7 Example 20 0.50 28 91 3.5 5.7 63 99.8 Example 21 4.48 27 90 3.7 6.0 62 100 Example 22 0.50 28 92 3.6 5.9 64 99.7 Example 23 0.50 30 90 3.8 5.9 55 99.9 Example 24 0.50 28 91 3.3 5.9 79 99.7 Example 25 0.50 20 91 3.3 6.0 82 99.6 Example 26 0.50 20 90 3.5 5.9 69 99.7 Example 27 0.50 22 90 3.4 6.0 76 99.8 Example 28 0.49 26 91 3.7 5.9 59 99.9 Example 29 0.50 27 90 3.8 6.0 58 99.8 Example 30 0.50 28 92 3.0 5.7 90 99.6 Comparative Example 0.50 4 52 4.6 11.1 141 66.2 18 200906484 Table 4 Pd content in the catalyst of the example (% by weight) Content in the layer at a depth of 5 nm under the surface of the catalyst (% by weight ) Content in the layer at a depth of 300 nm under the surface of the catalyst (% by weight) Example 1 0.50 50.2 22.3 Example 2 0.50 51.2 23.7 Example 3 0.20 43.1 11.8 Example 4 0.08 30.1 5.9 Example 5 0.50 52.6 20.4 Example 6 0.60 57.8 28.0 Example 7 0.50 60.1 23.5 Example 8 3.50 63.4 29.3 Example 9 0.50 54.3 24.2 Example 10 0.50 51.4 23.6 Example 11 0.49 50.3 23.2 Example 12 0.15 40.6 11.3 Example 13 0.50 52.3 23.7 Example 14 0.40 50.4 20.5 Example 15 0.50 52.9 24.9 Example 16 0.49 50.4 23.1 Example 17 0.50 56.3 23.0 Example 18 0.98 70.1 30.3 Example 19 0.50 57.8 23.6 Example 20 0.50 53.5 23.8 Example 21 4.48 83.2 40.2 Example 22 0.50 56.1 21.2 Example 23 0.50 50.6 24.7 Example 24 0.50 53.4 25.3 Example 25 0.50 54.5 23.0 Example 26 0.50 55.6 27.4 Example 27 0.50 56.4 23.7 Example 28 0.49 53.3 23.9 Example 29 0.50 50.1 20.1 Example 30 0.50 56.5 24.7 Comparative Example 0.50 30.6 12.5 19 200906484 The patents, specifics and test methods mentioned in the specification of the present application are hereby incorporated by reference. The present invention will be described with reference to the exemplary embodiments, and various changes and modifications may be made without departing from the spirit and scope of the invention. The present invention is not limited to the specific palladium solutions disclosed as the best mode for carrying out the invention, but includes all embodiments falling within the scope of the appended claims. [Simple diagram description] None [Main component symbol description] None 20

Claims (1)

200906484 X. Patent application scope: ι_ A supported palladium/carbon catalyst, in the form of microcrystals, and complex, and the carrier activated carbon is more than 80% by weight of the total. . 5 nm microcrystals account for palladium crystallites 2. According to the scope of the patent application, the negative (four) dragon / silk enthalpy, its supported palladium field is concentrated on the surface layer of the carrier activated carbon / carbonization The full content of the agent is the total weight of the catalyst. 50+〇1〇=% in the case where the carrier activated carbon ❹ = metal granules account for the total atomic weight of the layer in the layer of the mountain, the surface of the rock family is too much weight% or more; The gold of the layer f of the weight is 5% by weight or more of the total atomic weight in the layer. 3. According to the loaded dragon/carbon catalyst described in the second paragraph of the patent scope, in the case where the amount of the carbon/catalyst is 〇5〇±〇ι〇% by weight based on the total weight of the catalyst, on the surface of the activated carbon of the carrier The metal in the layer of the lower 5 nm depth accounts for more than 4% by weight of the total atomic weight in the layer; the metal in the layer of 300 nm depth under the carrier active I·sheng surface saturates the layer 10% by weight or more of the total atomic weight. 4. The supported type of charcoal catalyzed according to any one of claims 3 to 3, wherein the supported palladium is highly dispersed on the surface of the supported activated carbon. Not less than 5%. . 5. The supported palladium/carbon catalyst according to claim 4, wherein the supported palladium has a dispersion of not less than 1% by weight. 6. The supported palladium/carbon catalyst according to any one of claims 1-5, wherein the catalyst is at 5 ° C, and is bubbled through 25 ° c 21 2009 06484 supported palladium The average grain size of the water in the nitrogen stream is calcined for ίο, not more than 6.0 nm. 7. The negatively-loaded palladium/carbon catalyst according to any one of the claims of the invention, wherein the catalyst contains 金属. 5~|n 3堇% of the metal Pd, based on the catalyst Total weight. 8. The supported palladium/carbon catalyst according to claim 7, wherein the catalyst contains 0.2 to 3 - 5 wt% of metal pd, based on the total weight of the catalyst. 9. A method of preparing a supported catalyst according to the scope of claim 1, comprising the steps of: a) first washing the activated carbon with a mineral acid aqueous solution, then washing with water to neutrality, and drying the washing. The activated carbon is obtained as an activated carbon support; b) the activated carbon support is impregnated or sprayed with an aqueous solution containing a Pd compound and an additive, and the Pd compound (4) is obtained on the activated carbon support to obtain a catalyst precursor, wherein the aqueous solution is obtained. The molar ratio of Pd in the additive to the cerium compound is 0.01:1~2 〇:1, and the additive is selected from the compound represented by the following formula I: Ri-(CH2)n-CHCOOH R2 ~~ (CH2)nT·CCOOH R3~ (CH2)i -chcooh The nm and 1 in the gas are independently selected from the integers of 〇 and 卜5, and R1~ and R3 are independently selected from H, CH3, NH2, OH and COOH; the pH of the palladium solution is adjusted to 7± 3; and 22 200906484 C) The catalyst precursor is subjected to a reduction treatment with a reducing agent to obtain a supported type of carbon/catalyst. 10. The method according to claim 9, wherein the inorganic acid is at least one selected from the group consisting of hydrochloric acid, nitric acid and phosphoric acid; the pickling time is 〇5 to 8 hours; and the acid concentration of the inorganic acid solution is 〇 〇丨~5 〇 耳 / liter; Dry at a temperature of 80 ~ 150 ° C for 5 ~ 1 〇 hours. 11. The method according to claim 9 or claim 1, wherein the pd compound is selected from the group consisting of Pd, palladium acetate, palladium nitrate, chloropalladium acid, basic salt of chloropalladium acid, palladium ammonia complex and a combination thereof; the concentration of Pd in the pd-containing solution is 0.01 to 20%; the molar ratio of Pd in the solution to the Pd compound is 〇〇1:1~2 〇:1. 12. The method according to item n of the patent application, wherein the pd compound is chloropalmitoic acid or palladium acetate; the pH of the solution containing the Pd compound and the additive is 4 to 9; the concentration of the Pd in the solution is the sum of the solution The molar ratio of pd in the additive to the Pd compound is 〇〇5:1~1_5:1. The method according to any one of claims 9 to 12, further comprising aging the catalyst precursor at a temperature of from 0 to 80 ° C for from 1 to 50 hours before the reduction treatment. 14. The method according to any one of the preceding claims, wherein the reducing agent is selected from the group consisting of formic acid, sodium formate, formaldehyde, hydrazine hydrate, glucose, hydrogen, and combinations thereof; and the reduction treatment is in 〇~2 The temperature of 〇〇t is carried out for 0.5 to 24 hours. 15. The method according to claim 14, wherein the catalyst precursor 23 200906484 is aged at a temperature of 8 〇〇c before the reduction treatment, and the agent is sodium formate or hydrazine hydrate for 24 hours; and the reduction treatment is at 20 ~12 "c: Degrees are carried out for 1 to 1 hour. The method of the load shaft/carbon catalyst described in the above-mentioned patent range of item i includes the following steps: 1) washing the granular or shaped activated carbon carrier with an aqueous acid solution for 0.5 to 8 hours, The acid aqueous solution has an acid concentration of 〇〇1 to 3 〇mol/L, and the acid is one selected from the group consisting of hydrochloric acid, nitric acid and phosphoric acid; 2) the acid washed activated carbon carrier is washed with water to neutrality, and then at 80~ Drying at 150 ° C for 0.5 to 10 hours gives the treated activated carbon support, 3) impregnation with the aqueous solution containing the water-soluble Pd compound and an additive of the following formula I or the treated activated carbon carrier And a Pd compound is supported on the treated activated carbon support to obtain a catalyst precursor, wherein the content of the Pd compound in the aqueous solution is 〇·丄 10% by weight in terms of Pd, and the molar ratio of the additive to Pd In the range of 〇.〇5: 1~1.5:1, the pH of the aqueous solution is adjusted to 7±3, Ri ~ (CH2)n-CHCOOH R2-(CH2)m-CCOOH R3-(CH2) plant CHCOOH Wherein n, m and 1 are independently 0 or 1 to 5; and Ri, R2 and R3 are independent Selected from OH, hydrazine, CH3, NH2 and COOH; 24 200906484 4) The catalyst precursor obtained from step 3) is aged at 0 to 80 ° C for 1 to 50 hours; and 5) the aged catalyst precursor The reduction treatment is carried out with a reducing agent to reduce the Pd ions in the Pd compound to the metal Pd, and the catalyst is produced. The purity of the catalyst is 200906484. 7. The designated representative figure: (1) The representative figure of the case is: the (none) figure. (2) A brief description of the symbol of the representative figure: 8. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: