Extruded Titania-Based Materials Comprising One or More Acids or Prepared Using One or More Acids

Abstract

Porous, extruded titania-based materials further comprising one or more acids and/or prepared using one or more acids, Fischer-tropsch catalysts comprising them, uses of the foregoing, processes for making and using the same and products obtained from such processes.

Claims

1. A porous, extruded titania-based material further comprising one or more acids.

2. A porous, extruded titania-based material according to claim 1, in the form of symmetrical cylinders, dilobes, trilobes, quadralobes or hollow cylinders.

3. A porous, extruded titania-based material according to claim 1, having a crush strength of greater than 3.0 lbf.

4. A porous, extruded titania-based material according to claim 1, wherein the one or more acids comprises propionic acid, malic acid, oxalic acid, valeric acid, carbonic acid, formic acid, citric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, sulphuric acid and mixtures thereof.

5. A porous, extruded titania-based material according to claim 1, comprising mesopores and macropores.

6. A porous, extruded titania-based material according to claim 5, wherein the mesopores have a pore diameter of 2 to 50 nm.

7. A porous, extruded titania-based material according to claim 5, wherein the macropores have a pore diameter of greater than 50 nm.

8. A porous, extruded titania-based material according to claim 5, wherein the total pore volume is at least 0.30 ml/g.

9. A porous, extruded titania-based material according to claim 5, wherein the surface area is at least 30 m.sup.2/g.

10. A process for the preparation of a porous, extruded titania-based material having a crush strength greater than 3.0 lbf, said process comprising: a) mixing titanium dioxide and one or more acids, and optionally a liquid extrusion medium, to form a homogenous paste; b) extruding the paste to form an extrudate; and c) drying and/or calcining the extrudate.

11. A process according to claim 10 wherein the one or more acids comprises propionic acid, malic acid, oxalic acid, valeric acid, carbonic acid, formic acid, citric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, sulphuric acid and mixtures thereof.

12. A porous, extruded titania-based material obtainable by the process of claim 10.

13. A process for the preparation of a porous, extruded titania-based material comprising mesopores and macropores and having a crush strength greater than 3.0 lbf, said process comprising: a) mixing titanium dioxide and one or more porogens to form a homogenous mixture; b) adding of one or more acids, and optionally a liquid extrusion medium, to the homogenous mixture, and mixing to form a homogenous paste; c) extruding the paste to form an extrudate; and d) drying and/or calcining the extrudate at a temperature sufficient to decompose the one or more porogens.

14. A process according to claim 13, wherein the one or more acids comprises propionic acid, malic acid, oxalic acid, valeric acid, carbonic acid, formic acid, citric acid, acetic acid, nitric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, sulphuric acid and mixtures thereof.

15. A process according to claim 13, wherein the one or more porogen comprises cellulose or a derivative thereof, such as methyl cellulose, ethyl cellulose and ethyl methyl cellulose; alginic acid or a derivative thereof, such as ammonium alginate, sodium alginate and calcium alginate; latex or polyvinyl chloride.

16. A process according to claim 13, wherein the weight ratio of titanium dioxide to porogen is from 1:0.1 to 1:1.0.

17. A porous, extruded titania-based material obtainable by a process according to claim 13.

18-32. (canceled)

33. A porous, extruded titania-based material according to claim 5, wherein the mesopores have a pore diameter of 25 to 40 nm.

34. A porous, extruded titania-based material according to claim 5, wherein the macropores have a pore diameter of 100 to 850 nm.

35. A porous, extruded titania-based material according to claim 5, wherein the total pore volume is at least 0.30 ml/g, and the surface area is at least 30 m.sup.2/g.

Description

EXAMPLES

Comparative Example 1

Titania Extrudate Formed with Distilled Water

[0097] Titanium dioxide (BASF P25) was mixed in a mechanical mixer (Vinci MX 0.4) with sufficient distilled water to form an extrudable paste, for example at a water to titanium mass ratio of 0.66 g/g. The resultant paste was extruded through a die with an array of 1/16 inch circular orifices using a mechanical extruder (Vinci VTE1) to obtain extrudates with cylindrical shape.

[0098] The extrudates were air dried for one hour, then dried at a temperature of between 100 and 120 C. overnight, followed by calcination in air flow at 500 C. for four hours, via a ramp of 2 C./min.

[0099] The mechanical strength of the extrudates was analysed using a Varian Benchsaver V200 Tablet Hardness Tester. 50 particles were analysed in each test, and the mean value was calculated.

[0100] The surface area of the extrudates was estimated using the BET model to the nitrogen adsorption branch of the isotherms collected at 77K on a Quadrasorb SI unit (Quantachrome).

[0101] The physical properties of the extrudates were as follows:

[0102] Geometry: 1/16 inch diameter cylinder

[0103] Crush strength: 4.7 lbf

[0104] BET surface area: 51 m.sup.2/g

Example 1

Titania Extrudate Prepared Using 1.0 Mol/L Nitric Acid

[0105] The procedure of Comparative Example 1 was repeated, with the exception that the distilled water was replaced by a 1.0 mol/L aqueous solution of nitric acid.

[0106] The physical properties of the extrudates of Example 1 were determined as set out in Comparative Example 1, and the results are as follows:

[0107] Geometry: 1/16 inch diameter cylinder

[0108] Crash strength: 13.7 lbf

[0109] BET surface area: 42 m.sup.2/g

[0110] Compared with the pure titania extrudates prepared in Comparative Example 1, the extrudates of Example 1 prepared using 1.0 mol/L nitric acid exhibited substantially higher mechanical strength.

[0111] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as 40 mm is intended to mean about 40 mm.

[0112] Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0113] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope and spirit of this invention.