Hydroisomerization of pentane utilizing Pd exchanged mordenite

#An improved zeolite catalyst of high acidity for reactions such as the isomerization of normal hydrocarbons, and methods of making and using are taught. Other reactions for which highly acid catalysts are desireable are alkylation and cracking of hydrocarbons.

#U.S. Pat. Nos. 3,475,345; 3,324,188; and 3,190,939 teach the use of large port hydrogen exchanged mordenite as a catalyst for hydrocarbon isomerization. The first named patent discloses that strong, hot acid leaching followed by mild acid leaching, finally followed by ammonium exchange results in an improved isomerization catalyst as compared to mordenite in which one or more of the 3 steps of the treatment is omitted.

#The process of the present invention involves ammonium exchange of large port mordenite followed by mild acid treatment. Such treatment results in a catalyst more active and selective toward hydrocarbon isomerization than previously known mordenite catalysts. Incorporation of a noble metal into the catalyst further improves its selectively.

#The starting material in the following example was large port sodium mordenite, made according to the teaching of U.S. Pat. No. 3,436,174, in pelletized form bonded by a silicious bond. The 1/16" pellets contained 6.1% Na.sub.2 0, and the silica to alumina mole ratio was 10.5 to 1.

#The sodium zeolite was treated with 3 to 5 normal NH.sub.4 NO.sub.3 solutions until chemical analysis showed a constant 0.27% by weight of Na.sub.2 O (on an anhydrous basis). The product was washed free of NH.sub.4 NO.sub.3 solution by repeated washings with water. Two hundred grams of the washed product was treated by boiling for four hours in 400 ml. of 0.5 normal HC1. After washing free of acid, the product was found to contain 0.23% Na.sub.2 O, and had a silica to alumina ration of 10.7 to 1, after calcination for 24 hours at a maximum temperature of 550.degree. C.

#The testing procedure for isomerization employed a 1 to 1 volume mixture of the mordenite pellets with inert fused alumina aggregate. The process conditions were a temperature of the bed of 480.degree. F., pressure of 450 p.s.i.g., hydrogen to normal pentane feed mole ratio of 7/1 and weight hourly space velocity of 1.00 gram of normal C-5 per gram of catalyst per hour.