Regeneration of nickel-aluminum catalysts by polycarboxylic acid washing

Abstract

Abstract The method of regenerating a granular, foraminous nickelaluminum catalyst which has been activated by removing about 2-50 percent of the aluminum from a nickel-aluminum alloy originally containing about 25-60 percent by weight of nickel and about 4075 percent by weight of aluminum and which has lost activity through use as a fixed-bed catalyst in the preparation of butane1,4-diol by the continuous hydrogenation of an aqueous mixture containing about 30-80 percent by weight of water and diol selected from the group consisting of 2-butyne-1,4-diol and 2butene-1,4-diol at a temperature of about 60-150*C., a hydrogen pressure of about 100-400 atmospheres and a superficial gas velocity of at least about 0.5 foot per minute which comprises washing the catalyst with a wash medium consisting essentially of about 90-99 percent by weight of water and about 1-10 percent by weight of a polycarboxylic acid selected from the group consisting of citric and succinic acids. Such catalysts can be reactivated by first washing with the above polycarboxylic acid solution and then treating with a dilute aqueous alkali metal hydroxide solution, thereby removing additional aluminum from the alloy. Catalysts which have become fouled through use of an aqueous feed mixture containing dissolved calcium ions can be regenerated by washing the catalyst with the above polycarboxylic acid solution until the wash liquid no longer becomes saturated with calcium ions.

Inventors

• 👤 John Stuart Coates

Bibliographic Details