GB716235A - Improvements in and relating to catalysts - Google Patents

Abstract

Substantially spherical catalytic bodies, adapted for use in a continuous chemical process involving a liquid phase and a static bed, are prepared by mixing an adjuvant and a particulate material to obtain a plastic mass, dividing the plastic mass into pieces and moulding the pieces into approximate spheres of diameter 1/16 -\ba3/4 inch (preferably 1/8 -\ba3/8 inch) by means of two surfaces between which there is relative movement, and then heating the spheres to a moderate temperature. Catalytic substances may be present in the particulate material or may be introduced in solution or suspension in a liquid adjuvant such as water, a solution of sugar or gum, a volatile organic liquid, or a mineral oil; grease or petroleum may also be used as the adjuvant. Alternatively catalytic material may be applied to the spheres after moulding and heating. The plastic mass may be extruded into cylinders, cut into pieces and then rolled between two corrugated surfaces or between two rubber band conveyers moving in opposite directions at different speeds, the upper band having a lateral reciprocating motion. Specified catalytic materials are aqueous gels of aluminium or ferric hydroxide, tungstic oxide or sulphide, and a mixture of kieselguhr and phosphoric acid. In an example, boron phosphate formed by reacting orthophosphoric acid and boric acid, is ground, made into a paste with water formed into spheres and dried. The Provisional Specification refers to forming the spheres by granulation in a mixer, or by adding graphite and pelleting by means of tools having hemispherical concave tips. The preparation of mullite spheres according to Specification 715,882 is disclaimed. Specifications 220,649, [Class 1 (i)], 340,239 and 608,849, [Group XIII], also are referred to.ALSO:Substantially spherical catalytic bodies are prepared by mixing an adjuvant and a particulate material to obtain a plastic mass, dividing the plastic mass into pieces and moulding the pieces into approximate spheres of diameter 1/16 -\ba3/4 inch (preferably 1/8 -\ba3/8 inch) by means of two surfaces between which there is relative movement, and then heating the spheres to a moderate temperature. Catalytic substances may be present in the particulate material or may be introduced in solution or suspension in a liquid adjuvent such as water, a solution of sugar or gum, a volatile organic liquid, or a mineral oil; grease or petrolatum may also be used as the adjuvant. Alternatively catalytic material may be applied to the spheres after moulding and heating. The plastic mass may be extruded into cylinders, cut into pieces, and then rolled between two corrugated surfaces or between two rubber band conveyers moving in opposite p directions at different speeds, the upper band having a lateral reciprocating motion. Specified catalytic materials are aqueous gels of aluminium or ferric hydroxide, tungstic oxide of sulphide, and a mixture of kieselghur and phosphoric acid. In an example boron phosphate, formed by reacting orthophosphoric acid and boric acid, is ground, made into a paste with water formed into spheres, and dried. The Provisional Specification refers to forming the spheres by granulation in a mixer, or by adding graphite and pelletting by means of tools having hemispherical concave tips. The preparation of mullite spheres according to Specification 715,882, [Group III], is disclaimed Specifications 220,649, [Class I (i)], 340,239, [Group III], and 608,849, [Group XII], also are referred to.