of the catalyst of this invention a suitable porous catalyst support is first impregnated with an aqueous solution of a water soluble copper salt e g cupric nitrate trihydrate cupric chloride anhydrous or dihydrate cupric acetate cupric sulfate or cupric bromide and the like impregnation techniques known in the art may be employed to impregnate the copper salt preferably the impregnation can be accomplished by the 34 incipient wetness 34 method wherein an amount of copper compound solution used for the impregnation is from about 95 to about 100 percent of the absorptive capacity of the support material the concentration of the solution is such that the amount of elemental copper in the impregnated solution is equal to a predetermined amount within the range for example of about 0 3 to about 5 0 preferably about 0 5 to about 3 0 grams liter of catalyst the catalyst support material is composed of particles having any of various regular or irregular shapes such as spheres tablets cylinders rings stars or other shapes and may have dimensions such as diameter length or width of about 1 to about 10 mm preferably about 3 to 9 mm spheres having a diameter of about 4 to about 8 mm are preferred the support material may be composed of any suitable porous substance e g silica alumina silica alumina titania zirconia silicates aluminosilicates titanates spinel silicon.