Shaped channeled catalyst

DETAILED DESCRIPTION The shaped catalysts of this invention are generally cylindrically shaped, having longitudinal channels in the surface of the cylinder which extend radially toward the central region of the cylinder.
The cross-section of the channeled cylinder can be circular, elliptical, or even irregularly shaped.
Protrusions are defined between the longitudinally extending channels.
In order to reduce the probability of interlocking between adjacent catalyst particles, it is important that the protrusions have larger maximum widths than the channels.
For example, a ratio of the maximum width of the protrusions to the maximum width of the channels can be from about 1.
05 to 20; preferably, from about 1.
2 to 3.
The width of the channel and of the protrusions is measured in a direction perpendicular to a line extending from the central axis of the cylindrical shape.
In the case of cylinders having irregular or non-circular cross-sections, the central axis is defined as the axis passing through the center of the smallest circle which circumscribes the cross-sectional area.
Preferably, the maximum widths of the distal portion of the protrusions are larger than the external widths of the channels.
By external width, it is meant the width of the channel at the surface of the cylindrical shape farthest from the axis.
The ratio of the maximum width of the distal one-half or one-fourth (by radial length) of the protrusions to the external width of the channels should be in the range of 1.
05 to 20, preferably in the range of 1.
2 to 3.
The width and the depth of the channels are determined by the required catalyst strength and the desired liquid hold-up time for reactants.
Deeper channels result in increased liquid hold-up time and decreased strength.
Wider channels result in decreased liquid hold-up time and decreased strength.
The catalyst of this invention can be easily prepared by extruding a catalyst mixture by conventional methods through an appropriately shaped die.
The extrudate may be cut or broken to provide the desired catalyst length