Zeolite-catalyzed ring-shift isomerization of sym-octahydrophenanthrene and conformational isomerization of cis-decahydronaphthalene

✍ Scribed by Chunshan Song; Kimberly Moffatt

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 647 KB
• Volume: 2
• Category: Article
• ISSN: 0927-6513
• DOI: 10.1016/0927-6513(94)00023-9

✦ Synopsis

This paper reports on two zeolite-catalyzed isomerization reactions of polycyclic hydrocarbons. The first is the transformation of 1 2 3 4 5 6 7 8-octahydrophenanthrene (sym-OHP) to 1 2 3 4 5 6 7 S-octahydroanthracene

(sym-,,,*,33 ,,,33>)

OHAn), which we call ring-shift isomerization. Among the Y zeolites and mordenites tested, a proton-form mordenite (HML8) with relatively lower SiOZ/Al,03 ratio afforded a higher yield of sym-OHAn with a higher sym-OHAn/sym-OHP ratio. The best selectivities towards sym-OHAn with HML8 at 250°C are 89-91% at 58-59% conversion of sym-OHP in decalin and in mesitylene solvents. The second is the conversion of cis-decahydronaphthalene (cis-DeHN) to trans-DeHN, which may be called conformational isomerization. For this reaction, a La ion-exchanged Y zeolite (LaHY) displayed the best selectivity with a trans-DeHN/cis-DeHN ratio of over 10 at 250°C.