Method for the production of acrylic acid and method for the preparation of the catalyst

Abstract: A catalyst excelling in catalytic properties and allowing a partially oxidized organic compound to be produced stably in a high yield for a long time, a method of preparation suitable for the preparation of the catalyst, and a method for the production of a partially oxidized organic compound by the use of the catalyst are disclosed. A catalyst for catalytic gas phase production of a partially oxidized organic compound having a catalytically active component supported on a carrier such that water, after undergoing the treatment described below, exhibits specific resistance exceeding a prescribed magnitude, a method for the preparation of the catalyst, and a method for the production of a partially oxidized organic compound by the use of the catalyst. (Treatment) In a conical beaker having an inner volume of 500 ml, 300 ml of a given carrier is placed and dried at 120°C for two hours and then the dried carrier and (amount of water absorption + 220) ml of purified water added thereto are heated together under normal pressure at 90°C for 30 minutes.

Description: BACKGROUND OF THE INVENTION Field of the Invention: This invention relates to a method for the preparation of a catalyst for the gas phase partial oxidation of acrolein, and a method for producing acrylic acid using the catalyst. Description of the Related Art: For the production of acrylic acid, it has been widely practiced on a commercial scale a method which adopts acrolein as a raw material and effects gas phase partial oxidation thereof with molecular oxygen in the presence of a catalyst. In the catalysts for use in this production of acrylic acid, the catalysts are mainly used which have molybdenum-vanadium as a main component. Patents which have issued to inventions covering molybdenum-vanadium type catalysts include those disclosed in JP-B-50-25,914, GB 1 488 889, GB 1 488 890, US 3,773,692, US 3,867,438, US 4,414,412 etc. While these catalysts for the production of acrylic acid have already reached the point where they exhibit yields of high levels, they are still required to offer further improved yields. The reason for this is that since acrylic acid is now produced on a large scale, even a slight improvement of yield brings a very high economic effect due to economization of raw material. Further, the improvement of such a catalyst in service life and durability brings about an extremely large economic effect. Owing to this situation, the development of a catalyst for the production of acrylic acid which excels in catalytic qualities such as activity, selectivity, and service life constitutes a constant theme for researchers in the relevant technical field. SUMMARY OF THE INVENTION An object of this invention is to provide the use of a catalyst for the gas phase partial oxidation of acrolein which excels in catalytic qualities and enables the target product to be obtained stably in a high yield for a long time. Another object of this invention is to provide a method of preparation suitable for the preparation of the used catalyst. According to the first embodiment of this invention, it provides use of a catalyst for the gas phase partial oxidation of acrolein which comprising a catalytically active component supported on an inert carrier containing silica-alumina or steatite, the carrier fulfills the condition that the water after the following treatment exhibits specific resistance of not less than 10,000 Ω * cm (25°C): (method of treatment) In a conical beaker having an inner volume of 500 ml, 300 15 ml of a given carrier is placed and dried at 120°C for two hours and then the dried carrier and (amount of water absorption + 220) ml of purified water added thereto are heated at 90°C under normal pressure for 30 minutes, wherein the amount of water absorption is represented as follows: Amount of water absorption = A/B wherein A = 300 (ml) x packing density (g/ml) x water absorption ratio (wt. %)/100 and B = density of water (g/ml). The method for the production of a acrylic acid comprises effecting gas phase partial oxidation of acrolein or acrolein containing gas with a molecular oxygen or a molecular oxygen-containing gas in the presence of the catalyst mentioned above. Further, according to the second embodiment of this invention, it provides a method for the preparation of a catalyst for the gas phase partial oxidation of an organic substrate, which comprises supporting a catalytically active component on an inert carrier containing silica-alumina or steatite, the carrier fulfills the condition that the water after the following treatment exhibits specific resistance of not less than 10,000 Ω * cm (25°C) in the case of producing an unsaturated aldehyde or an unsaturated carboxylic acid having not less than three carbon atoms and containing at least one double bond: (method of treatment) In a conical beaker having an inner volume of 500 ml, 300 ml of a given carrier is placed and dried at 120°C for two hours and then the dried carrier and (amount of water absorption + 220) ml of purified water added thereto are heated at 90°C under normal pressure for 30 minutes, wherein the amount of water absorption is represented as follows: Amount of water absorption = A/B wherein A = 300 (ml) x packing density (g/ml) x water absorption ratio (wt. %)/100 and B = density of water (g/ml). The catalyst used for the production of acrylic acid according to this invention excels in activity, selectivity, and service life and enables the acrylic acid to be produced in a high yield for a long time. The above and other objects, features, and advantages of the present invention will become clear from the following description of the preferred embodiments. DESCRIPTION OF THE PREFERRED EMBODIMENTS The treatment to be used in this invention prior to the determination of the specific resistance of water is performed by the following method: In a conical beaker having an inner volume of 500 ml (based an Japanese Industrial Standard (JIS) R-3503), 300 ml of a given carrier is placed and dried at 120°C for two hours and then the dried carrier and (amount of water absorption +220) ml of purified water added thereto are heated at 90°C under normal pressure for 30 minutes, wherein the amount of water absorption is represented as follows: Amount of water absorption A/B wherein A = 300 (ml) x packing density (g/ml) x water absorption 30 ratio (wt. %)/100 and B = density of water (g/ml). The term "packing density (D)" used in the preceding formula means the magnitude which is represented by the formula, D = W1 (g) /1000 ml (wherein W1 denotes the weight of the carrier which fills a measuring cylinder, 65 mm in inside diameter 1000 ml in inner volume, when the dried carrier is fed into the measuring cylinder at a rate of 2000 ml/minute). The term "water absorption ratio (M)" used therein means the magnitude which is represented by the formula, M = [(W3 (g) - W2 (g)) /W2 (g)] (wherein W2 denotes the weight of 300 ml of the dried carrier and W3 denotes the weight found after 300 ml of the dried carrier is placed in a basket made of stainless steel wire, heated in boiling purified water for 30 minutes, then removed from the basket, wiped with a wet gauze till removal of excess water, and weighed). The following description is based an (I) acrylic acid as the partial oxidized aliphatic compounds. (I) Partial oxidized aliphatic compounds Specifically, this invention includes the preparation of a catalyst for the production of acrylic acid which comprising the oxide or complex oxide of a metal element composition having molybdenum and vanadium as main components thereof and a inert carrier containing silica-aluminium or steatite on which the metal element composition is supported, characterized by the carrier used therein causing the water after undergoing the treatment mentioned above to exhibit specific resistance of not less than 10,000 Ω * cm (25°C). The carrier to be used in preparing an oxidizing catalyst for the production of acrylic acid by the gas phase partial oxidation of acrolein or an acrolein-containing gas is silica•alumina or steatite. The carrier containing silica-aluminuim or steatite is not particularly discriminated on account of physical properties, shape, size etc. As respects physical properties, the specific surface area thereof is not more than 2 m /g and preferred to be in the range of 0.01 - 1.5 m 2 /g, the water absorption ratio thereof in the range of 0 - 70%, preferably 0 - 50%, and the average pore diameter thereof in the range of 1 - 1,500 µm, preferably 5 - 500 µm. The shape may be arbitrarily selected from among sphere, cylinder, hollow cylinder etc. The size is in the range of 1 - 10 mm, preferably 3 - 8 mm, in diameter in the case of spheres. This invention is characterized by using a carrier containing silica-aluminium or steatite which causes the water after undergoing the treatment mentioned above to exhibit specific resistance of not less than 10,000 Ω * cm (25°C). Specifically, the carrier to be used is such that when 300 ml of the carrier is placed in a conical beaker having an inner volume of 500 ml and dried at 120°C for two hours, and then the dried carrier and (amount of water absorption + 220) ml of purified water added thereto are heated at 90°C under normal pressure for 30 minutes, the water subsequently to this treatment exhibits specific resistance not less than 1x10 4 Ω * cm (25°C), preferably falling in the range of 15,000 - 1x10 6 Ω * cm (25°C), and particularly preferably falling in the range of 2x10 4 - 1x10 6 Ω * cm (25°C). The term "specific resistance" herein refers to the magnitude which is the reciprocal of the conductivity of water determined after the treatment mentioned above at 25°C by the use of a conductivity meter. In this invention, when the specific resistance is 10,000 Ω * cm, for example, it is expressed as 10,000 Ω * cm (25°C) The carrier containing silica-aluminium or steatite which exhibits the specific resistance of not less than 10,000 Ω * cm (25°C) for the water after the treatment mentioned above can be advantageously prepared by washing a given carrier containing silica-aluminium or steatite with water, preferably purified water, to a certain level. One concrete method for effecting this washing consists in that the specific resistance for the water after the treatment mentioned above exceeds 1x10 4 Ω * cm (25°C), preferably falls in the range of 15,000 to 1x10 6 Ω * cm (25°C), and more preferably 20,000 - 1x10 6 Ω * cm (25°C), for example by repeating an operation of heating a carrier containing silica-aluminium or steatite under normal pressure at 90°C for 30 minutes. This operation does not need to be repeated when the first round of the operation allows the specific resistance for the water after the treatment mentioned above reaches a level exceeding 10,000 Ω * cm (25°C). When the operation is performed a plurality of times, each operation must use newly supplied water and require this water to be tested for specific resistance subsequently to the treatment mentioned above. The amount of water to be used for the washing does not need to be particularly limited. When the carrier containing silica-aluminium or steatite has a volume of 300 ml, for example, the amount of water to be used is the sum of amount of water absorption and 220 ml in the first round of the operation and 220 ml each in the second and subsequent rounds. This is because the treated carrier containing silica-aluminium or steatite contains the water corresponding to the amount of water absorption. Prior to the washing with water described above, the car- z rier containing silica-aluminium or steatite may be washed with an acidic aqueous solution such as of nitric acid, a basic aqueous solution such as of ammonia water, or an organic solvent such as an alcohol. When an aqueous nitric acid solution, for example, is used for this preparatory washing, it is commendable to repeat an operation of heating the carrier under normal pressure at 90°C. In this case, the catalyst which has undergone this operation must be washed with water. During this washing with water, however, the carrier is not always required to heat under normal pressure at 90°C. The means for washing the carrier containing silica-aluminium or steatite does not need to be particularly restricted. The carrier containing silica-aluminium or steatite may be washed by being heated in conjunction with a washing liquid or by being exposed to a reduced pressure or increased pressure. The catalyst which excels in catalytic qualities used for the acrylic acid production can be obtained by washing the carrier preferably with water as described above or using the carrier exhibiting specific resistance of not less than 10,000 Ω * cm (25°C) for the water after the treatment mentioned above. The catalyst used for producing acrylic acid according to this invention can be prepared in accordance with the method known to the art except that the carrier containing silica-aluminium or steatite described above is used instead. Specifically, the composition of catalyst, the method for preparation, the kind of carrier containing silica-aluminium or steatite and the method for supporting of a catalyst component on the carrier containing silica-aluminium or steatite may be each any of those known to the art. In the method for the preparation of the catalyst, the metal compounds to be used do not need to be limited to ammonium salts and nitrates but may be selected from among various oxides, carbonates, chlorides, sulfates, hydroxides, organic acid salts etc. The amount of the catalytic component to be supported is not particularly limited but is only required to be such that the produced catalyst permits effective production of acrylic acid by gas phase partial oxidation of acrolein. This amount, for example, is in the range of 1 - 200 wt. %, preferably 10 - 100 wt. %, based on the weight of the carrier for producing acrylic acid. The production of acrylic acid by the gas phase partial oxidation of acrolein or an acrolein-containing gas in the presence of the catalyst of this invention has no particular restriction. It can be effected by any of the methods which can be used for reactions of this kind and which are popularly known as usable therefor. The production, for example, only requires acrolein or an acrolein-containing gas to contact with the catalyst at a temperature in the range of 180 - 350°C, preferably 200 - 330°C, under normal pressure or by application of pressure. EXAMPLE Now, this invention will be described more specifically below with reference to examples. The conductivity was measured with a conductivity meter (available from Horiba K.K. in Japan as a type of "DS-12"). Example I-1 Three liters of a silica-alumina carrier (spheres, 3/16 inch in diameter, packing density 1.20 g/ml, and water absorption ratio 20%) was heated in three liters of purified water at 90°C for 30 minutes to wash. 676 g of Ammonium molybdate, 149 g of ammonium metavanadate, 215 g of ammonium paratungstate and 3,500 ml of water were mixed and heated with stirring to dissolve. Separately, 154 g of copper nitrate was dissolved in 200 ml of water while the water was heating and stirring. The two aqueous solutions consequently obtained were mixed and placed in a ceramic evaporation dish held on a water bath. The mixed aqueous solution and two liters of the washed carrier dried thoroughly at 120°C were together stirred in the dish and the catalyst component was supported on the carrier by means of evaporation and solidification. The resultant composite was heat-treated under a stream of air at 400°C for six hours to obtain a catalyst 1. The metal element composition of this catalyst excepting oxygen was as follows: Mo 12 V 4 W 2.5 Cu 2 In a conical beaker, 500 ml in inner volume (based an JIS R-3503), 300 ml of the remaining washed carrier was placed and dried at 120°C for two hours and the dried carrier and 292 ml [=(300 X 1.20 X 0.2) + 220] of purified water added thereto were heated under normal pressure at 90°C for 30 minutes. After treatment, the water was separated from the beaker and tested for conductivity. As a result, the water had a specific resistance of 16,300 Ω * cm (25°C). Example I-2 Three liters of the same carrier as used in Example I-1 and 3 liters of purified water added thereto were heated together at 90°C for 30 minutes to wash the carrier. After treatment, the water was separated from the beaker. Two liters of purified water were newly added in the same beaker and the above same treatment was repeated to wash the carrier. The procedure of Example I-1 was repeated except that the carrier washed twice was used instead to obtain a catalyst 2. The conductivity was measured in the same manner as used in Example I-1, and as a result, the water had a specific resistance of 23,100 Ω * cm (25°C). Example I-3 Three liters of the same carrier as used in Example I-1 and 3 liters of purified water added thereto were heated together at 90°C for 30 minutes to wash the carrier. After treatment, the water was separated from the beaker. Two liters of purified water were newly added in the same beaker and the above same treatment was repeated to wash the carrier. This operation was repeated once more. 676 g of Ammonium molybdate, 149 g of ammonium metavanadate, 215 g of ammonium paratungstate and 3,500 ml of water were mixed and heated with stirring to dissolve. Separately, 154 g of copper nitrate and 200 ml of water were mixed and heated with stirring to dissolve. The two aqueous solutions consequently obtained were mixed and evaporated and solidified while heating and stirring. The resultant blocks were dried in a drier at 120°C for five hours and then pulverized to about 100 meshes of a powder. In a centrifugal flow coating apparatus, 2 liters of the washed carrier thoroughly dried in advance at 120°C was placed and subsequently the aforementioned powder was thrown in together with distilled water as a binding agent while hot air at 90°C was blown in order to support the catalyst components on the carrier. The spherical particles thus obtained were heat-treated under a stream of air at 400°C far six hours to obtain a catalyst 3. The conductivity was measured in the same manner as used in Example I-1, and as a result, the water had a specific resistance of 24,700 Ω * cm (25°C) Example I-4 Three liters of the same carrier as used in Example I-1 and 3 liters of an aqueous nitric acid solution (2 mols/liter) added thereto were heated together under normal pressure at 90°C for 30 minutes to wash the carrier. After treatment, the nitric acid solution was separated from the beaker. Two liters of purified water were newly added in the same beaker and the above same treatment was repeated to wash the carrier. This operation was repeated once more. The procedure of Example I-1 was repeated except that the carrier washed mentioned above was used instead to obtain a catalyst 4. The conductivity was measured in the same manner as used in Example I-1, and as a result, the water had a specific resistance of 21, 600 Ω * cm (25°C). Comparative Example I-1 As for the raw carrier not washed as used in Example I-1, the conductivity was measured in the same manner as used in Example 1-1, and as a result, the water had a specific resistance of 8,500 Ω * cm (25°C). The procedure of Example I-1 was repeated except that the carrier not washed mentioned above was used instead to obtain a catalyst 5. Example I-5 Three liters of a steatite carrier (spheres, 3/16 inch in diameter, packing density 1.30 g/ml, and water absorption ratio 5%) and three liters of purified water were heated at 90°C for 30 minutes. Then, the water was separated and then the remaining carrier and 2 liters of newly added purified water were heated together at 90°C for 30 minutes to wash the carrier. This operation was repeated once more. The procedure of Example I-1 was repeated except that the washed carrier mentioned above was used instead to obtain a catalyst 6. In a conical beaker, 500 ml in inner volume, 300 ml of the remaining carrier was placed and dried at 120°C for two hours. Then, the dried carrier and 240 ml [=(300 x 1.30 x 0.05) +220] of purified water added thereto were heated together under normal pressure at 90°C for 30 minutes. After treatment, the water was separated from the beaker and tested for conductivity. As a result, the water had a specific resistance of 20,600 Ω * cm (25°C). Example I-6 Three liters of the same carrier as used in Example I-5 and 3 liters of ammonia water (ammonia content 29%) added thereto were heated together under normal pressure at 90°C for 30 minutes. Then, the ammonia water was removed and then the remaining carrier and 2 liters of newly added purified water were heated together at 90°C for 30 minutes to wash the carrier. This operation was repeated once more. The procedure of Example I-3 was repeated except that the washed carrier mentioned above was used instead to obtain a catalyst 7. The conductivity was measured in the same manner as used in Example I-5, and as a result, the water had a specific resistance of 13,300 Ω * cm (25°C). Comparative Example I-2 As for the raw carrier not washed as used in Example 1-5, the conductivity was measured in the same manner as used in Example I-5, and as a result, the water had a specific resistance of 7,900 Ω * cm (25°C). The procedure of Example I-1 was repeated except that the carrier not washed mentioned above was used instead to obtain a catalyst 8. Example I-7 (not according to the invention) Three liters of a titania-zirconia carrier (3/16-inch spheres, packing density 1.0 g/ml, and water absorption ratio 30%) was heated in three liters of purified water at 90°C for 30 minutes to wash. Then, the water was separated and then the remaining carrier and 2 liters of newly added purified water were heated together at 90°C for 30 minutes to wash the carrier. This operation was repeated once more. The procedure of Example I-1 was repeated except that the washed carrier mentioned above was used instead to obtain a catalyst 9. In a conical beaker, 500 ml in inner volume, 300 ml of the washed carrier was placed and dried at 120°C for two hours. Then, the dried carrier and 310 ml [= (300 x 1.0 x 0.3) + 220] of purified water added thereto were heated together under normal pressure at 90°C for 30 minutes. After treatment, the water was separated from the beaker and tested for conductivity. As a result, the water had a specific resistance of 11,900 Ω * cm (25°C). Comparative Example I-3 As for the raw carrier not washed as used in Example I-7, the conductivity was measured in the same manner as used in Example I-7, and as a result, the water had a specific resistance of 9,000 Ω * cm (25°C). The procedure of Example I-1 was repeated except that the carrier not washed mentioned above was used instead to obtain a catalyst 10. Example I-8 In a U-shaped stainless steel tube, 25 mm in inside diameter, 500 ml of each catalyst (catalyst 1 - catalyst 10) obtained in Examples I-1 to I-7 and Comparative Examples I-1 to I-3 respectively was loaded, a reaction gas of the following composition was then introduced to the catalyst bed at a space velocity (SV) of 2,000 Hr -1 and allowed to react: Acrolein 5 vol. % Air 25 vol. % Steam 20 vol. % Nitrogen 50 vol. % The results are shown in Table I-1. Example I-9 The catalysts (catalyst 1 and catalyst 5) obtained in Example I-1 and Comparative Example I-1 respectively were each made to react under the conditions described in Example I-8. This reaction was carried out continuously for 4,000 hours. The results are shown in Table I-2.

Claims: A method for the production of acrylic acid, characterized by effecting gas phase partial oxidation of acrolein or acrolein containing gas with molecular oxygen or a molecular oxygen containing gas in the presence of a catalyst comprising an inert carrier containing silica-alumina or steatite and a catalytically active component supported thereon, the catalytically active component containing an oxide or a complex oxide of a metal element composition represented by the formula 1: Mo a V b W c Cu d X e Y f Z g O h wherein Mo represents molybdenum, V vanadium, W tungsten, Cu copper, X at least one element selected from the group consisting of zirconium, titanium, and cerium, Y at least one element selected from the group consisting of magnesium, calcium, strontium, and barium, Z at least one element selected from the group consisting of niobium, antimony, tin, tellurium, phosphorus, cobalt, nickel, chromium, manganese, zinc, and bismuth, O oxygen, and b = 1 - 14, 0 < c ≤ 12, 0 < d ≤ 6, e = 0 - 10, f = 0 - 3, g = 0 - 10, and h the numerical value to be determined by the state of partial oxidation of the component elements where a = 12, characterized by the carrier fulfilling the condition that: the water after being used in the following treatment exhibits specific resistance of not less than 10,000 Ω cm (25°C) treatment: in a conical beaker having an inner volume of 500 ml, 300 ml of a given carrier is placed and dried at 120°C for two hours and then the dried carrier and (amount of water absorption + 220) ml of purified water added thereto are heated together under normal pressure at 90°C for 30 minutes, wherein the amount of water absorption is represented by: Amount of water absorption = A/B wherein A = 300 (ml) x packing density (g/ml) x water absorption ratio (% by weight)/ 100 and B = density of water (g/ml). A method for preparing a catalyst for gas phase partial oxidation of acrolein, the catalyst comprising an inert carrier containing silica-alumina or steatite and a catalytically active component supported thereon, the catalytically active component containing an oxide or a complex oxide of a metal element composition represented by the formula 1: Mo a V b W c Cu d X e Y f Z g O h wherein Mo represents molybdenum, V vanadium, W tungsten, Cu copper, X at least one element selected from the group consisting of zirconium, titanium, and cerium, Y at least one element selected from the group consisting of magnesium, calcium, strontium, and barium, Z at least one element selected from the group consisting of niobium, antimony, tin, tellurium, phosphorus, cobalt, nickel, chromium, manganese, zinc, and bismuth, O oxygen, and b = 1 - 14, 0 < c ≤ 12, 0 < d ≤ 6, e = 0 - 10, f = 0 - 3, g = 0 - 10, and h the numerical value to be determined by the state of partial oxidation of the component elements where a = 12, washing the carrier by placing 300 ml of the carrier in a conical beaker having an inner volume of 500 ml, drying at 120°C for two hours, adding (amount of water absorption + 220) ml of purified water thereto, wherein the amount of water absorption is represented by: amount of water absorption = A/B wherein A = 300 (ml) x packing density (g/ml) x water absorption ratio (% by weight)/100 and B = density of water (g/ml), heating together under normal pressure at 90°C for 30 minutes, and eventually repeating this above treatment, the water after being used in the following treatment exhibiting a specific resistance of not less than 10,000 Ω cm (25°C), and depositing the catalytically active component on the carrier.

Inventors: KIYOOKA YASUSHI, NAKAMURA DAISUKE, OKUNO MASAAKI, TAKAHASHI TSUKASA, TANIMOTO MICHIO, YUNOKI HIROMI, KIYOOKA, YASUSHI, NAKAMURA, DAISUKE, OKUNO, MASAAKI, TAKAHASHI, TSUKASA, TANIMOTO, MICHIO, YUNOKI, HIROMI, Kiyooka, Yasushi, Nippon Shokubai Hamadashataku, Okuno, Masaaki, Life Court Kitano 305, Yunoki, Hiromi, Nippon Shokubai Hamadashataku
Applicants: NIPPON CATALYTIC CHEM IND, NIPPON SHOKUBAI CO., LTD.
Application year: 1999
Main classification: B01J23
IPC codes: B01J37, B01J35, B01J23, C07C51