502 / | HD | CATALYST, SOLID SORBENT, OR SUPPORT THEREFOR: PRODUCT OR PROCESS OF MAKING |
100 | DF | CATALYST OR PRECURSOR THEREFOR {12} |
300 | DF | .~ Metal, metal oxide or metal hydroxide {10} |
305 | DF | .~.~ Of Group VI (i.e., Cr, Mo, W or Po) {8} |
323 | .~.~.~ And Group III metal containing (i.e., Sc, Y, Al, Ga, In or Tl) |