| 585 / | HD | CHEMISTRY OF HYDROCARBON COMPOUNDS |
| 800 | DF | PURIFICATION, SEPARATION, OR RECOVERY {7} |
| 833 | DF | .~ By addition of extraneous agent, e.g., solvent, etc. {15} |
| 856 | | .~.~ S containing {2} |
| 857 | DF | .~.~.~> S dioxide, sulfolane, or sulfolene |
| 858 | DF | .~.~.~> Sulfuric acid {1} |