METHOD FOR PRODUCING CATALYSTS AND THEIR USE FOR THE GAS PHASE OXIDATION OF OLEFINS

• US 20100022796A1
• Filed: 12/06/2007
• Published: 01/28/2010
• Est. Priority Date: 12/13/2006
• Status: Active Grant

• Current Assignee: Wacker Chemie AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Original Assignee: Wacker Chemie AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Inventors: Heidenreich, Roland, Weis, Johann, Eberle, Hans-Jurgen
• Granted Patent: US 8,410,014 B2
• Time in Patent Office: Days
• US Class Current: 560/208
• CPC Class Codes: B01J 21/08 Silica
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 23/52 Gold
• CPC Class Codes: B01J 23/58 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/60 with zinc, cadmium or mercury
• CPC Class Codes: B01J 23/66 Silver or gold
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/638 more than 1.0 ml/g
• CPC Class Codes: B01J 37/0009 Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
• CPC Class Codes: B01J 37/0036 Grinding
• CPC Class Codes: B01J 37/0201 Impregnation
• CPC Class Codes: B01J 37/0205 in several steps
• CPC Class Codes: C07C 67/055 in the presence of platinum group metals or their compounds
• CPC Class Codes: C07C 69/01 Vinyl esters
• CPC Class Codes: C07C 69/15 Vinyl acetate

Abstract

Especially physically stable metal oxide catalyst supports are prepared by suspending a metal oxide in a continuous phase, activating by fine dispersion, coagulation to a viscoelastic mass, shaping, drying, and calcining. The catalyst support thus prepared may be treated with catalytic agents to produce supported catalysts for olefin oxidation.

Claims

1-40. -40. (canceled)

41. A process for producing catalysts for the gas-phase oxidation of olefins, which comprises the steps:

(1) optionally suspending at least one pyrogenic metal oxide in a liquid phase,

(2) converting the metal oxide into an active state in a continuous phase by producing a fine metal oxide dispersion by means of a dispersing apparatus and/or wet milling,

(3) coagulating the dispersion to give a viscoelastic mass,

(4) converting the viscoelastic mass into a shaped body,

(5) drying the shaped body,

(6) calcining the shaped body obtained in step (5),

(7) converting the shaped body into an active catalyst by application of one or more catalytically active compounds or one or more precursor compounds and/or one or more promoter compounds which can be converted in a subsequent step into one or more catalytically active compounds.

42. The process of claim 41, wherein one or more compounds from the group consisting of Si_xO_y, Al_xO_y, Ti_xO_y, Zr_xO_y, Ce_xO_y are used as pyrogenic metal oxide.

43. The process of claim 42, wherein SiO₂ is used as a pyrogenic metal oxide.

44. The process of claim 41, wherein the continuous phase comprises water.

45. The process of claim 41, wherein the activation is carried out in a frictional mill, an annular gap mill or a stirred ball mill.

46. The process of claim 41, wherein activation is carried out by means of one or more dispersing apparatuses selected from the group consisting of dissolvers, ultrasonic dispersers and planetary dissolvers.

47. The process of claim 41, wherein suspension of the metal oxide in the continuous phase is omitted and the addition of the metal oxide to the continuous phase is carried out during the activation step.

48. The process of claim 41, wherein the suspension is activated for a period of from 0.5 to 4 hours.

49. The process of claim 41, wherein one or more beads made of steel, glass, aluminium oxide, zirconium oxide, zirconium silicate, silicon carbide, or silicon nitride, are used as a milling media.

50. The process of claim 41, wherein the pH during suspension and during activation step is in the range of from 2.0 to 4.0.

51. The process of claim 50, wherein the pH is regulated by means of hydrochloric acid, nitric acid, ammonia, or an aqueous solution thereof.

52. The process of claim 41, wherein the solids content of the activated metal oxide dispersion is from 5 to 40% by weight.

53. The process of claim 41, wherein coagulation of the metal oxide dispersion is achieved by adjusting the pH, further addition of one or more metal oxides, or a combination thereof.

54. The process of claim 41, wherein coagulation of the metal oxide dispersion containing the activated metal oxide is achieved by adjusting the pH to a value in the range from 4 to 10.

55. The process of claim 41, wherein coagulation of the metal oxide dispersion containing the activated metal oxide is carried out by further addition of one or more metal oxides.

56. The process of claim 41, wherein shaping is carried out by extrusion, tableting, or pressing.

57. The process of claim 41, wherein the shaped bodies have the shape of rings, pellets, cylinders, wagon wheels or spheres.

58. The process of claim 41, wherein the shaped bodies are dried at temperatures in the range from 25°

C. to 200°

C.

59. The process of claim 41, wherein calcining is carried out under an air atmosphere, with the oxygen content optionally varied, and a further gas optionally being added to the air.

60. The process of claim 41, wherein calcining is carried out at a temperature in the range from 500°

C. to 1250°

C.

61. The process of claim 41, wherein the shaped catalyst bodies formed have a BET surface area in the range from 30 m²/g to 500 m²/g.

62. The process of claim 41, wherein the addition of one or more promoter compounds is carried out in a separate step after at least partial conversion of the shaped bodies into a catalyst by addition of a catalytic component or precursor thereof.

63. The process of claim 41, wherein application of one or more promoter compounds is carried out separately in a process step preceding or following the application of one or more catalytically active compounds or one or more precursor thereof.

64. The process of claim 41, wherein the shaped bodies are coated with one or more of catalytic systems selected from the group consisting of Pd/Au/alkali metal compounds, Pd/Cd/alkali metal compounds and Pd/Ba/alkali metal compounds.

65. The process of claim 64, wherein system components are applied by means of impregnation, spraying, vapour deposition, dipping, precipitation of Pd and/or Au and/or Cd and/or Ba metal compounds on the support, reduction of the reducible metal compounds applied to the support, washing to remove any chloride present, and impregnation with alkali metal acetate or alkali metal compounds, in an appropriate order.

66. The process of claim 65, wherein potassium compounds are used as alkali metal compounds.

67. The process of claim 41, wherein one or more noble metal compounds are applied in one step or in a plurality of successive steps, and one or more steps selected from the group consisting of intermediate drying, calcination, and reduction are optionally carried out between these steps.

68. The process of claim 41, wherein chloride present on the support is removed by thorough washing before and/or after reduction of the noble metal compounds.

69. The process of claim 68, wherein washing of the catalyst is carried out by means of water or a basic aqueous solution having a pH of >

7.

70. The process of claim 41, wherein the catalyst comprises, based on the weight of the support used, one or more components from the group consisting of from 0.1 to 5.0% by weight of palladium, from 0.2 to 3.5% by weight of gold, from 0.1 to 3.5% by weight of cadmium, from 0.1 to 3.5% by weight of barium and from 0.5 to 15% by weight of potassium.

71. The process of claim 41, wherein a noble metal concentration is constant within the support body.

72. The process of claim 41, wherein a noble metal concentration decreases from the accessible outer surface in the direction of the interior of the support.

73. The process of claim 41, wherein the sum of all impurities in the catalyst is less than 400 ppm.

74. A catalyst prepared by the process of claim 41.

75. The catalyst of claim 74, wherein the shaped body has a sum of impurities of all other metals, carbon, phosphorus, and sulphur, of less than 400 ppm.

76. In a process for a chemical reaction, wherein the improvement comprises employing a catalyst of claim 74 as a catalyst in the chemical reaction.

77. A process for a catalyzed oxidation for preparing unsaturated esters from olefins and/or organic acids, comprising contacting an oxidizable substrate with a supported catalyst of claim 74.

78. The process of claim 77, which is a process for the production of vinyl acetate monomer.

79. The process of claim 77, which is a process for the acetoxylation of olefins.