| 502 / | HD | CATALYST, SOLID SORBENT, OR SUPPORT THEREFOR: PRODUCT OR PROCESS OF MAKING |
| 100 | DF | CATALYST OR PRECURSOR THEREFOR {12} |
| 202 | | .~ Boron or compound containing same {3} |
| 203 | DF | .~.~> Boron halide |
| 204 | DF | .~.~> And Group VI metal containing (i.e., Cr, Mo, W or Po) {2} |
| 207 | DF | .~.~> And Group VIII metal containing (i.e., iron or platinum group) |